auto import from //depot/cupcake/@135843

21 files changed, 0 insertions, 8842 deletions

diff --git a/contrib/gregbook/COPYING b/contrib/gregbook/COPYING
deleted file mode 100644
index d60c31a..0000000
--- a/contrib/gregbook/COPYING
+++ /dev/null
@@ -1,340 +0,0 @@
-		    GNU GENERAL PUBLIC LICENSE
-		       Version 2, June 1991
-
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.
-     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-			    Preamble
-
-  The licenses for most software are designed to take away your
-freedom to share and change it.  By contrast, the GNU General Public
-License is intended to guarantee your freedom to share and change free
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-Foundation's software and to any other program whose authors commit to
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-the GNU Library General Public License instead.)  You can apply it to
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-
-		    GNU GENERAL PUBLIC LICENSE
-   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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-  0. This License applies to any program or other work which contains
-a notice placed by the copyright holder saying it may be distributed
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-
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-either of that version or of any later version published by the Free
-Software Foundation.  If the Program does not specify a version number of
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-  10. If you wish to incorporate parts of the Program into other free
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-			    NO WARRANTY
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-  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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-  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
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-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
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-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-
-		     END OF TERMS AND CONDITIONS
-
-	    How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
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-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
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-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
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-Also add information on how to contact you by electronic and paper mail.
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-    Gnomovision version 69, Copyright (C) year  name of author
-    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
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-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, the commands you use may
-be called something other than `show w' and `show c'; they could even be
-mouse-clicks or menu items--whatever suits your program.
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-You should also get your employer (if you work as a programmer) or your
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-
-  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-  `Gnomovision' (which makes passes at compilers) written by James Hacker.
-
-  <signature of Ty Coon>, 1 April 1989
-  Ty Coon, President of Vice
-
-This General Public License does not permit incorporating your program into
-proprietary programs.  If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library.  If this is what you want to do, use the GNU Library General
-Public License instead of this License.
diff --git a/contrib/gregbook/LICENSE b/contrib/gregbook/LICENSE
deleted file mode 100644
index d956717..0000000
--- a/contrib/gregbook/LICENSE
+++ /dev/null
@@ -1,50 +0,0 @@
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------
diff --git a/contrib/gregbook/Makefile.mingw32 b/contrib/gregbook/Makefile.mingw32
deleted file mode 100644
index e70a59a..0000000
--- a/contrib/gregbook/Makefile.mingw32
+++ /dev/null
@@ -1,130 +0,0 @@
-# Sample makefile for rpng-win / rpng2-win / wpng using mingw32-gcc and make.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a DOS-prompt window via:
-#
-#	make -f Makefile.mingw32
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are in subdirectories at the same level as the current subdirectory
-# (as indicated by the PNGDIR and ZDIR macros below).  It makes no assumptions
-# at all about the mingw32 installation tree (W32DIR).  Edit as appropriate.
-#
-# Note that the names of the dynamic and static libpng and zlib libraries
-# used below may change in later releases of the libraries.  This makefile
-# builds both statically and dynamically linked executables by default.
-# (You need only one set, but for testing it can be handy to have both.)
-
-
-# macros --------------------------------------------------------------------
-
-#PNGDIR = ../..#		for libpng-x.y.z/contrib/gregbook builds
-PNGDIR = ../libpng-win32
-PNGINC = -I$(PNGDIR)
-PNGLIBd = $(PNGDIR)/libpng.dll.a	# dynamically linked
-PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
-
-#ZDIR = ../../../zlib-win32#	for libpng-x.y.z/contrib/gregbook builds
-ZDIR = ../zlib-win32
-ZINC = -I$(ZDIR)
-ZLIBd = $(ZDIR)/libzdll.a
-ZLIBs = $(ZDIR)/libz.a
-
-# change this to be the path where mingw32 installs its stuff:
-W32DIR =
-#W32DIR = /usr/local/cross-tools/i386-mingw32msvc
-W32INC = -I$(W32DIR)/include
-W32LIB = $(W32DIR)/lib/libuser32.a $(W32DIR)/lib/libgdi32.a
-
-CC = gcc
-#CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
-LD = $(CC)
-RM = rm -f
-CFLAGS = -O -Wall $(INCS) $(MINGW_CCFLAGS)
-# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
-LDFLAGS = $(MINGW_LDFLAGS)
-O = .o
-E = .exe
-
-INCS = $(PNGINC) $(ZINC) $(W32INC)
-RLIBSd = $(PNGLIBd) $(ZLIBd) $(W32LIB) -lm
-RLIBSs = $(PNGLIBs) $(ZLIBs) $(W32LIB) -lm
-WLIBSd = $(PNGLIBd) $(ZLIBd)
-WLIBSs = $(PNGLIBs) $(ZLIBs)
-
-RPNG   = rpng-win
-RPNG2  = rpng2-win
-WPNG   = wpng
-
-ROBJSd  = $(RPNG)$(O) readpng.pic$(O)
-ROBJS2d = $(RPNG2)$(O) readpng2.pic$(O)
-WOBJSd  = $(WPNG)$(O) writepng.pic$(O)
-
-RPNGs  = $(RPNG)-static
-RPNG2s = $(RPNG2)-static
-WPNGs  = $(WPNG)-static
-
-ROBJSs  = $(RPNG)$(O) readpng$(O)
-ROBJS2s = $(RPNG2)$(O) readpng2$(O)
-WOBJSs  = $(WPNG)$(O) writepng$(O)
-
-STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
-DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-%.pic$(O): %.c
-	$(CC) -c $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNGs)$(E): $(ROBJSs)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJSs) $(RLIBSs)
-
-$(RPNG)$(E): $(ROBJSd)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJSd) $(RLIBSd)
-
-$(RPNG2s)$(E): $(ROBJS2s)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2s) $(RLIBSs)
-
-$(RPNG2)$(E): $(ROBJS2d)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2d) $(RLIBSd)
-
-$(WPNGs)$(E): $(WOBJSs)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJSs) $(WLIBSs)
-
-$(WPNG)$(E): $(WOBJSd)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJSd) $(WLIBSd)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O) readpng.pic$(O):	readpng.c readpng.h
-readpng2$(O) readpng2.pic$(O):	readpng2.c readpng2.h
-writepng$(O) writepng.pic$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES)
-	$(RM) $(ROBJSs) $(ROBJS2s) $(WOBJSs)
-	$(RM) $(ROBJSd) $(ROBJS2d) $(WOBJSd)
diff --git a/contrib/gregbook/Makefile.sgi b/contrib/gregbook/Makefile.sgi
deleted file mode 100644
index e3ca6ce..0000000
--- a/contrib/gregbook/Makefile.sgi
+++ /dev/null
@@ -1,104 +0,0 @@
-# Sample makefile for rpng-x / rpng2-x / wpng for SGI using cc and make.
-# Greg Roelofs
-# Last modified:  7 March 2002
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
-#	and family, too.  (Not that this is a blatant plug or anything.)
-#
-# Invoke this makefile from a shell prompt in the usual way; for example:
-#
-#	make -f Makefile.sgi
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are both installed in /usr/local/{include,lib} (as indicated by the
-# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
-# the PNGINC, PNGLIB, ZINC and ZLIB lines.
-#
-# This makefile builds dynamically linked executables (against libpng and zlib,
-# that is), but that can be changed by uncommenting the appropriate PNGLIB and
-# ZLIB lines.
-
-
-# macros --------------------------------------------------------------------
-
-PNGINC = -I/usr/local/include/libpng12
-PNGLIB = -L/usr/local/lib -lpng12	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng12.a # statically linked against libpng
-# or:
-#PNGINC = -I../..
-#PNGLIB = -L../.. -lpng
-#PNGLIB = ../../libpng.a
-
-ZINC = -I/usr/local/include
-ZLIB = -L/usr/local/lib -lz		# dynamically linked against zlib
-#ZLIB = /usr/local/lib/libz.a		# statically linked against zlib
-#ZINC = -I../zlib
-#ZLIB = -L../zlib -lz
-#ZLIB = ../../../zlib/libz.a
-
-XINC = -I/usr/include/X11		# old-style, stock X distributions
-XLIB = -L/usr/lib/X11 -lX11
-#XINC = -I/usr/openwin/include    	# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-#XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
-#XLIB = -L/usr/X11R6/lib -lX11
-
-INCS = $(PNGINC) $(ZINC) $(XINC)
-RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
-WLIBS = $(PNGLIB) $(ZLIB)
-
-CC = cc
-LD = cc
-RM = rm -f
-# ABI must be the same as that used to build libpng.
-ABI=
-CFLAGS = $(ABI) -O -fullwarn $(INCS)
-LDFLAGS = $(ABI)
-O = .o
-E =
-
-RPNG  = rpng-x
-RPNG2 = rpng2-x
-WPNG  = wpng
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/contrib/gregbook/Makefile.unx b/contrib/gregbook/Makefile.unx
deleted file mode 100644
index 7ff65bf..0000000
--- a/contrib/gregbook/Makefile.unx
+++ /dev/null
@@ -1,132 +0,0 @@
-# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a shell prompt in the usual way; for example:
-#
-#	make -f Makefile.unx
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are installed in /usr/local/{include,lib} or as otherwise indicated by
-# the PNG* and Z* macros below.  Edit as appropriate--choose only ONE each of
-# the PNGINC, PNGLIBd, PNGLIBs, ZINC, ZLIBd and ZLIBs lines.
-#
-# This makefile builds both dynamically and statically linked executables
-# (against libpng and zlib, that is), but that can be changed by modifying
-# the "EXES =" line.  (You need only one set, but for testing it can be handy
-# to have both.)
-
-
-# macros --------------------------------------------------------------------
-
-#PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng12
-#PNGLIBd = -L$(PNGDIR) -lpng12 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng12.a # statically linked, installed libpng
-# or:
-PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
-#PNGDIR = ../libpng
-PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng12	# dynamically linked
-PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
-
-ZDIR = /usr/local/lib
-#ZDIR = /usr/lib64
-ZINC = -I/usr/local/include
-ZLIBd = -L$(ZDIR) -lz			# dynamically linked against zlib
-ZLIBs = $(ZDIR)/libz.a			# statically linked against zlib
-# or:
-#ZDIR = ../zlib
-#ZINC = -I$(ZDIR)
-#ZLIBd = -Wl,-rpath,$(ZDIR) -L$(ZDIR) -lz  # -rpath allows in-place testing
-#ZLIBs = $(ZDIR)/libz.a
-
-#XINC = -I/usr/include			# old-style, stock X distributions
-#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
-#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
-XLIB = -L/usr/X11R6/lib -lX11
-#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
-
-INCS = $(PNGINC) $(ZINC) $(XINC)
-RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
-RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
-WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs)
-
-CC = gcc
-LD = gcc
-RM = rm -f
-CFLAGS = -O -Wall $(INCS) -DFEATURE_LOOP
-# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
-LDFLAGS =
-O = .o
-E =
-
-RPNG   = rpng-x
-RPNG2  = rpng2-x
-WPNG   = wpng
-
-RPNGs  = $(RPNG)-static
-RPNG2s = $(RPNG2)-static
-WPNGs  = $(WPNG)-static
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
-DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNGs)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSs)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSd)
-
-$(RPNG2s)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSs)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSd)
-
-$(WPNGs)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSs)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSd)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/contrib/gregbook/Makefile.w32 b/contrib/gregbook/Makefile.w32
deleted file mode 100644
index 3c08085..0000000
--- a/contrib/gregbook/Makefile.w32
+++ /dev/null
@@ -1,113 +0,0 @@
-# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a DOS prompt window via:
-#
-#	%devstudio%\vc\bin\vcvars32.bat
-#	nmake -nologo -f Makefile.w32
-#
-# where %devstudio% is the installation directory for MSVC / DevStudio.  If
-# you get "environment out of space" errors, create a desktop shortcut with
-# "c:\windows\command.com /e:4096" as the program command line and set the
-# working directory to this directory.  Then double-click to open the new
-# DOS-prompt window with a bigger environment and retry the commands above.
-# 
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are in subdirectories at the same level as the current subdirectory
-# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
-#
-# Note that the names of the dynamic and static libpng and zlib libraries
-# used below may change in later releases of the libraries.  This makefile
-# builds statically linked executables, but that can be changed by uncom-
-# menting the appropriate PNGLIB and ZLIB lines.
-
-!include <ntwin32.mak>
-
-
-# macros --------------------------------------------------------------------
-
-PNGPATH = ../libpng
-PNGINC = -I$(PNGPATH)
-#PNGLIB = $(PNGPATH)/pngdll.lib
-PNGLIB = $(PNGPATH)/libpng.lib
-
-ZPATH = ../zlib
-ZINC = -I$(ZPATH)
-#ZLIB = $(ZPATH)/zlibdll.lib
-ZLIB = $(ZPATH)/zlibstat.lib
-
-WINLIBS = -defaultlib:user32.lib gdi32.lib
-# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
-
-INCS = $(PNGINC) $(ZINC)
-RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
-WLIBS = $(PNGLIB) $(ZLIB)
-
-CC = cl
-LD = link
-RM = del
-CFLAGS = -nologo -O -W3 $(INCS) $(cvars)
-# [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
-# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
-O = .obj
-E = .exe
-
-RLDFLAGS = -nologo -subsystem:windows
-WLDFLAGS = -nologo
-
-RPNG  = rpng-win
-RPNG2 = rpng2-win
-WPNG  = wpng
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-#	ideally we could just do this:
-#	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
-#	...but the Windows "DEL" command is none too bright, so:
-	$(RM) r*$(E)
-	$(RM) w*$(E)
-	$(RM) r*$(O)
-	$(RM) w*$(O)
diff --git a/contrib/gregbook/README b/contrib/gregbook/README
deleted file mode 100644
index cb6e525..0000000
--- a/contrib/gregbook/README
+++ /dev/null
@@ -1,186 +0,0 @@
-                     ===========================
-                      PNG: The Definitive Guide
-                     ===========================
-
-                             Source Code
-
-Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
-cross-platform demo programs that show how to use the libpng reference
-library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
-a very simple example that that shows how a standard file-viewer might use
-libpng, while the second is designed to process streaming data and shows
-how a web browser might be written.  wpng is a simple command-line program
-that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
-of PBMPLUS/NetPBM) and converts them to PNG.
-
-The source code for all three demo programs currently compiles under
-Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
-zinser@decus.de, for making the necessary changes for OpenVMS and for
-providing an appropriate build script.)  Build instructions can be found
-below.
-
-Files:
-
-   README             this file
-   LICENSE            terms of distribution and reuse (BSD-like or GNU GPL)
-   COPYING            GNU General Public License (GPL)
-
-   Makefile.unx       Unix makefile
-   Makefile.w32       Windows (MSVC) makefile
-   makevms.com        OpenVMS build script
-
-   rpng-win.c         Windows front end for the basic viewer
-   rpng-x.c           X Window System (Unix, OpenVMS) front end
-   readpng.c          generic back end for the basic viewer
-   readpng.h          header file for the basic viewer
-
-   rpng2-win.c        Windows front end for the progressive viewer
-   rpng2-x.c          X front end for the progressive viewer
-   readpng2.c         generic back end for the progressive viewer
-   readpng2.h         header file for the progressive viewer
-
-   wpng.c             generic (text) front end for the converter
-   writepng.c         generic back end for the converter
-   writepng.h         header file for the converter
-
-   toucan.png         transparent PNG for testing (by Stefan Schneider)
-
-Note that, although the programs are designed to be functional, their
-primary purpose is to illustrate how to use libpng to add PNG support to
-other programs.  As such, their user interfaces are crude and definitely
-are not intended for everyday use.
-
-Please see http://www.libpng.org/pub/png/pngbook.html for further infor-
-mation and links to the latest version of the source code, and Chapters
-13-15 of the book for detailed discussion of the three programs.
-
-Greg Roelofs
-http://pobox.com/~newt/greg_contact.html
-16 March 2008
-
-
-BUILD INSTRUCTIONS
-
- - Prerequisites (in order of compilation):
-
-      - zlib		http://zlib.net/
-      - libpng		http://www.libpng.org/pub/png/libpng.html
-      - pngbook		http://www.libpng.org/pub/png/book/sources.html
-
-     The pngbook demo programs are explicitly designed to demonstrate proper
-     coding techniques for using the libpng reference library.  As a result,
-     you need to download and build both zlib (on which libpng depends) and
-     libpng.  A common build setup is to place the zlib, libpng and pngbook
-     subdirectory trees ("folders") in the same parent directory.  Then the
-     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
-     and similarly for the pngbook build.
-
-     Note that all three packages are designed to be built from a command
-     line by default; those who wish to use a graphical or other integrated
-     development environments are on their own.
-
-
- - Unix:
-
-     Unpack the latest pngbook sources (which should correspond to this
-     README file) into a directory and change into that directory.
-
-     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
-     appropriately (possibly also the X* variables if necessary).
-
-     make
-
-     There is no "install" target, so copy the three executables somewhere
-     in your path or run them from the current directory.  All three will
-     print a basic usage screen when run without any command-line arguments;
-     see the book for more details.
-
-
- - Windows:
-
-     Unpack the latest pngbook sources (which should correspond to this
-     README file) into a folder, open a "DOS shell" or "command prompt"
-     or equivalent command-line window, and cd into the folder where you
-     unpacked the source code.
-
-     For MSVC, set up the necessary environment variables by invoking
- 
-        %devstudio%\vc\bin\vcvars32.bat
-
-     where where %devstudio% is the installation directory for MSVC /
-     DevStudio.  If you get "environment out of space" errors under 95/98,
-     create a desktop shortcut with "c:\windows\command.com /e:4096" as
-     the program command line and set the working directory to the pngbook
-     directory.  Then double-click to open the new DOS-prompt window with
-     a bigger environment and retry the commands above.
-
-     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
-     appropriately (possibly also the "INC" and "LIB" variables if needed).
-     Note that the names of the dynamic and static libpng and zlib libraries
-     used in the makefile may change in later releases of the libraries.
-     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
-     This makefile therefore builds statically linked executables, but if
-     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
-     and ZLIB lines will build dynamically linked executables instead.
-
-     Do the build by typing
-
-        nmake
-
-     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
-     and wpng.exe.  Copy them somewhere in your PATH or run them from the
-     current folder.  Like the Unix versions, the two windowed programs
-     (rpng and rpng2) now display a usage screen in a console window when
-     invoked without command-line arguments; this is new behavior as of
-     the June 2001 release.  Note that the programs use the Unix-style "-"
-     character to specify options, instead of the more common DOS/Windows
-     "/" character.  (For example:  "rpng2-win -bgpat 4 foo.png", not
-     "rpng2-win /bgpat 4 foo.png")
-
-
- - OpenVMS:
-
-     Unpack the pngbook sources into a subdirectory and change into that
-     subdirectory.
-
-     Edit makevms.com appropriately, specifically the zpath and pngpath
-     variables.
-
-     @makevms
-
-     To run the programs, they probably first need to be set up as "foreign
-     symbols," with "disk" and "dir" set appropriately:
-
-     $ rpng  == "$disk:[dir]rpng-x.exe"
-     $ rpng2 == "$disk:[dir]rpng2-x.exe"
-     $ wpng  == "$disk:[dir]wpng.exe"
-
-     All three will print a basic usage screen when run without any command-
-     line arguments; see the book for more details.  Note that the options
-     style is Unix-like, i.e., preceded by "-" rather than "/".
-
-
-RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
-
-     rpng is a simple PNG viewer that can display transparent PNGs with a
-     specified background color; for example,
-
-	rpng -bgcolor #ff0000 toucan.png
-
-     would display the image with a red background.  rpng2 is a progressive
-     viewer that simulates a web browser in some respects; it can display
-     images against either a background color or a dynamically generated
-     background image.  For example:
-
-	rpng2 -bgpat 16 toucan.png
-
-     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
-     format (.pgm or .ppm) to PNG; for example,
-
-	wpng -time < toucan-notrans.ppm > toucan-notrans.png
-
-     would convert the specified PPM file (using redirection) to PNG, auto-
-     matically setting the PNG modification-time chunk.
-
-     All options can be abbreviated to the shortest unique value; for example,
-     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.
diff --git a/contrib/gregbook/makevms.com b/contrib/gregbook/makevms.com
deleted file mode 100644
index bd37dc0..0000000
--- a/contrib/gregbook/makevms.com
+++ /dev/null
@@ -1,132 +0,0 @@
-$!------------------------------------------------------------------------------
-$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
-$!
-$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
-$! for standalone pngbook source distribution.
-$!
-$!
-$!    Set locations where zlib and libpng sources live.
-$!
-$ zpath   = ""
-$ pngpath = ""
-$!
-$ if f$search("[---.zlib]zlib.h").nes."" then zpath = "[---.zlib]"
-$ if f$search("[--]png.h").nes."" then pngpath = "[--]"
-$!
-$ if f$search("[-.zlib]zlib.h").nes."" then zpath = "[-.zlib]"
-$ if f$search("[-.libpng]png.h").nes."" then pngpath = "[-.libpng]"
-$!
-$ if zpath .eqs. ""
-$ then
-$   write sys$output "zlib include not found. Exiting..."
-$   exit 2
-$ endif 
-$!
-$ if pngpath .eqs. ""
-$ then
-$   write sys$output "libpng include not found. Exiting..."
-$   exit 2
-$ endif 
-$!
-$!    Look for the compiler used.
-$!
-$ ccopt="/include=(''zpath',''pngpath')"
-$ if f$getsyi("HW_MODEL").ge.1024
-$ then
-$  ccopt = "/prefix=all"+ccopt
-$  comp  = "__decc__=1"
-$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$ else
-$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
-$   then
-$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
-$     then
-$      comp  = "__gcc__=1"
-$      CC :== GCC
-$     else
-$      comp = "__vaxc__=1"
-$     endif
-$   else
-$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
-$    ccopt = "/decc/prefix=all"+ccopt
-$    comp  = "__decc__=1"
-$  endif
-$ endif
-$ open/write lopt lib.opt
-$ write lopt "''pngpath'libpng.olb/lib"
-$ write lopt "''zpath'libz.olb/lib"
-$ close lopt
-$ open/write xopt x11.opt
-$ write xopt "sys$library:decw$xlibshr.exe/share"
-$ close xopt
-$!
-$!    Build 'em.
-$!
-$ write sys$output "Compiling PNG book programs ..."
-$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
-	readpng.c readpng.h
-$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
-	readpng2.c readpng2.h
-$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
-	writepng.c writepng.h
-$   write sys$output "Building rpng-x..."
-$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
-	rpng-x.c readpng.h
-$   call make rpng-x.exe -
-	"LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
-	rpng-x.obj readpng.obj
-$   write sys$output "Building rpng2-x..."
-$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
-	rpng2-x.c readpng2.h
-$   call make rpng2-x.exe -
-	"LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
-	rpng2-x.obj readpng2.obj
-$   write sys$output "Building wpng..."
-$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
-	wpng.c writepng.h
-$   call make wpng.exe -
-	"LINK wpng,writepng,lib.opt/opt" -
-	wpng.obj writepng.obj
-$ exit
-$!
-$!
-$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
-$ V = 'F$Verify(0)
-$! P1 = What we are trying to make
-$! P2 = Command to make it
-$! P3 - P8  What it depends on
-$
-$ If F$Search(P1) .Eqs. "" Then Goto Makeit
-$ Time = F$CvTime(F$File(P1,"RDT"))
-$arg=3
-$Loop:
-$       Argument = P'arg
-$       If Argument .Eqs. "" Then Goto Exit
-$       El=0
-$Loop2:
-$       File = F$Element(El," ",Argument)
-$       If File .Eqs. " " Then Goto Endl
-$       AFile = ""
-$Loop3:
-$       OFile = AFile
-$       AFile = F$Search(File)
-$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
-$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
-$       Goto Loop3
-$NextEL:
-$       El = El + 1
-$       Goto Loop2
-$EndL:
-$ arg=arg+1
-$ If arg .Le. 8 Then Goto Loop
-$ Goto Exit
-$
-$Makeit:
-$ VV=F$VERIFY(0)
-$ write sys$output P2
-$ 'P2
-$ VV='F$Verify(VV)
-$Exit:
-$ If V Then Set Verify
-$ENDSUBROUTINE
diff --git a/contrib/gregbook/readpng.c b/contrib/gregbook/readpng.c
deleted file mode 100644
index d87f6c7..0000000
--- a/contrib/gregbook/readpng.c
+++ /dev/null
@@ -1,304 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readpng.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "png.h"        /* libpng header; includes zlib.h */
-#include "readpng.h"    /* typedefs, common macros, public prototypes */
-
-/* future versions of libpng will provide this macro: */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
-#endif
-
-
-static png_structp png_ptr = NULL;
-static png_infop info_ptr = NULL;
-
-png_uint_32  width, height;
-int  bit_depth, color_type;
-uch  *image_data = NULL;
-
-
-void readpng_version_info(void)
-{
-    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
-      PNG_LIBPNG_VER_STRING, png_libpng_ver);
-    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
-      ZLIB_VERSION, zlib_version);
-}
-
-
-/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
-{
-    uch sig[8];
-
-
-    /* first do a quick check that the file really is a PNG image; could
-     * have used slightly more general png_sig_cmp() function instead */
-
-    fread(sig, 1, 8, infile);
-    if (!png_check_sig(sig, 8))
-        return 1;   /* bad signature */
-
-
-    /* could pass pointers to user-defined error handlers instead of NULLs: */
-
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* we could create a second info struct here (end_info), but it's only
-     * useful if we want to keep pre- and post-IDAT chunk info separated
-     * (mainly for PNG-aware image editors and converters) */
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-    png_init_io(png_ptr, infile);
-    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
-
-    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
-
-
-    /* alternatively, could make separate calls to png_get_image_width(),
-     * etc., but want bit_depth and color_type for later [don't care about
-     * compression_type and filter_type => NULLs] */
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-      NULL, NULL, NULL);
-    *pWidth = width;
-    *pHeight = height;
-
-
-    /* OK, that's all we need for now; return happy */
-
-    return 0;
-}
-
-
-
-
-/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
-
-int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
-{
-    png_color_16p pBackground;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
-        return 1;
-
-    /* it is not obvious from the libpng documentation, but this function
-     * takes a pointer to a pointer, and it always returns valid red, green
-     * and blue values, regardless of color_type: */
-
-    png_get_bKGD(png_ptr, info_ptr, &pBackground);
-
-
-    /* however, it always returns the raw bKGD data, regardless of any
-     * bit-depth transformations, so check depth and adjust if necessary */
-
-    if (bit_depth == 16) {
-        *red   = pBackground->red   >> 8;
-        *green = pBackground->green >> 8;
-        *blue  = pBackground->blue  >> 8;
-    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-        if (bit_depth == 1)
-            *red = *green = *blue = pBackground->gray? 255 : 0;
-        else if (bit_depth == 2)
-            *red = *green = *blue = (255/3) * pBackground->gray;
-        else /* bit_depth == 4 */
-            *red = *green = *blue = (255/15) * pBackground->gray;
-    } else {
-        *red   = (uch)pBackground->red;
-        *green = (uch)pBackground->green;
-        *blue  = (uch)pBackground->blue;
-    }
-
-    return 0;
-}
-
-
-
-
-/* display_exponent == LUT_exponent * CRT_exponent */
-
-uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
-{
-    double  gamma;
-    png_uint_32  i, rowbytes;
-    png_bytepp  row_pointers = NULL;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return NULL;
-    }
-
-
-    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
-     * transparency chunks to full alpha channel; strip 16-bit-per-sample
-     * images to 8 bits per sample; and convert grayscale to RGB[A] */
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_expand(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-        png_set_expand(png_ptr);
-    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-        png_set_expand(png_ptr);
-    if (bit_depth == 16)
-        png_set_strip_16(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-        png_set_gray_to_rgb(png_ptr);
-
-
-    /* unlike the example in the libpng documentation, we have *no* idea where
-     * this file may have come from--so if it doesn't have a file gamma, don't
-     * do any correction ("do no harm") */
-
-    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
-        png_set_gamma(png_ptr, display_exponent, gamma);
-
-
-    /* all transformations have been registered; now update info_ptr data,
-     * get rowbytes and channels, and allocate image memory */
-
-    png_read_update_info(png_ptr, info_ptr);
-
-    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
-    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
-
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return NULL;
-    }
-    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        free(image_data);
-        image_data = NULL;
-        return NULL;
-    }
-
-    Trace((stderr, "readpng_get_image:  channels = %d, rowbytes = %ld, height = %ld\n", *pChannels, rowbytes, height));
-
-
-    /* set the individual row_pointers to point at the correct offsets */
-
-    for (i = 0;  i < height;  ++i)
-        row_pointers[i] = image_data + i*rowbytes;
-
-
-    /* now we can go ahead and just read the whole image */
-
-    png_read_image(png_ptr, row_pointers);
-
-
-    /* and we're done!  (png_read_end() can be omitted if no processing of
-     * post-IDAT text/time/etc. is desired) */
-
-    free(row_pointers);
-    row_pointers = NULL;
-
-    png_read_end(png_ptr, NULL);
-
-    return image_data;
-}
-
-
-void readpng_cleanup(int free_image_data)
-{
-    if (free_image_data && image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (png_ptr && info_ptr) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        png_ptr = NULL;
-        info_ptr = NULL;
-    }
-}
diff --git a/contrib/gregbook/readpng.h b/contrib/gregbook/readpng.h
deleted file mode 100644
index fad9fe3..0000000
--- a/contrib/gregbook/readpng.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readpng.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-
-/* prototypes for public functions in readpng.c */
-
-void readpng_version_info(void);
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
-
-int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
-
-uch *readpng_get_image(double display_exponent, int *pChannels,
-                       ulg *pRowbytes);
-
-void readpng_cleanup(int free_image_data);
diff --git a/contrib/gregbook/readpng2.c b/contrib/gregbook/readpng2.c
deleted file mode 100644
index 9215042..0000000
--- a/contrib/gregbook/readpng2.c
+++ /dev/null
@@ -1,645 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                 readpng2.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-
-#include <stdlib.h>     /* for exit() prototype */
-
-#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
-#include "readpng2.h"   /* typedefs, common macros, public prototypes */
-
-
-/* local prototypes */
-
-static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
-static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
-                                 png_uint_32 row_num, int pass);
-static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
-static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
-
-
-
-
-void readpng2_version_info(void)
-{
-#if defined(PNG_ASSEMBLER_CODE_SUPPORTED) && \
-    (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__)) && \
-    defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
-    /*
-     * WARNING:  This preprocessor approach means that the following code
-     *           cannot be used with a libpng DLL older than 1.2.0--the
-     *           compiled-in symbols for the new functions will not exist.
-     *           (Could use dlopen() and dlsym() on Unix and corresponding
-     *           calls for Windows, but not portable...)
-     */
-    {
-        int mmxsupport = png_mmx_support();
-        if (mmxsupport < 0)
-            fprintf(stderr, "   Compiled with libpng %s; using libpng %s "
-              "without MMX support.\n", PNG_LIBPNG_VER_STRING, png_libpng_ver);
-        else {
-            int compilerID;
-            png_uint_32 mmx_mask = png_get_mmx_flagmask(
-              PNG_SELECT_READ | PNG_SELECT_WRITE, &compilerID);
-
-            fprintf(stderr, "   Compiled with libpng %s; using libpng %s "
-              "with MMX support\n   (%s version).", PNG_LIBPNG_VER_STRING,
-              png_libpng_ver, compilerID == 1? "MSVC++" :
-              (compilerID == 2? "GNU C" : "unknown"));
-            fprintf(stderr, "  Processor (x86%s) %s MMX instructions.\n",
-#if defined(__x86_64__)
-              "_64",
-#else
-              "",
-#endif
-              mmxsupport? "supports" : "does not support");
-            if (mmxsupport > 0) {
-                int num_optims = 0;
-
-                fprintf(stderr,
-                  "      Potential MMX optimizations supported by libpng:\n");
-                if (mmx_mask & PNG_ASM_FLAG_MMX_READ_FILTER_SUB)
-                    ++num_optims;
-                if (mmx_mask & PNG_ASM_FLAG_MMX_READ_FILTER_UP)
-                    ++num_optims;
-                if (mmx_mask & PNG_ASM_FLAG_MMX_READ_FILTER_AVG)
-                    ++num_optims;
-                if (mmx_mask & PNG_ASM_FLAG_MMX_READ_FILTER_PAETH)
-                    ++num_optims;
-                if (num_optims)
-                    fprintf(stderr,
-                      "         decoding %s row filters (reading)\n",
-                      (num_optims == 4)? "all non-trivial" : "some");
-                if (mmx_mask & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW) {
-                    fprintf(stderr, "         combining rows (reading)\n");
-                    ++num_optims;
-                }
-                if (mmx_mask & PNG_ASM_FLAG_MMX_READ_INTERLACE) {
-                    fprintf(stderr,
-                      "         expanding interlacing (reading)\n");
-                    ++num_optims;
-                }
-                mmx_mask &= ~( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \
-                             | PNG_ASM_FLAG_MMX_READ_INTERLACE    \
-                             | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
-                             | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
-                             | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
-                             | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH );
-                if (mmx_mask) {
-                    fprintf(stderr, "         other (unknown)\n");
-                    ++num_optims;
-                }
-                if (num_optims == 0)
-                    fprintf(stderr, "         (none)\n");
-            }
-        }
-    }
-#else
-    fprintf(stderr, "   Compiled with libpng %s; using libpng %s "
-      "without MMX support.\n", PNG_LIBPNG_VER_STRING, png_libpng_ver);
-#endif
-
-    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
-      ZLIB_VERSION, zlib_version);
-}
-
-
-
-
-int readpng2_check_sig(uch *sig, int num)
-{
-    return png_check_sig(sig, num);
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
-
-int readpng2_init(mainprog_info *mainprog_ptr)
-{
-    png_structp  png_ptr;       /* note:  temporary variables! */
-    png_infop  info_ptr;
-
-
-    /* could also replace libpng warning-handler (final NULL), but no need: */
-
-    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
-      readpng2_error_handler, NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* we could create a second info struct here (end_info), but it's only
-     * useful if we want to keep pre- and post-IDAT chunk info separated
-     * (mainly for PNG-aware image editors and converters) */
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function, unless an alternate error handler was installed--
-     * but compatible error handlers must either use longjmp() themselves
-     * (as in this program) or exit immediately, so here we are: */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
-    /* prepare the reader to ignore all recognized chunks whose data won't be
-     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
-     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
-    {
-        /* These byte strings were copied from png.h.  If a future libpng
-         * version recognizes more chunks, add them to this list.  If a
-         * future version of readpng2.c recognizes more chunks, delete them
-         * from this list. */
-        static const png_byte chunks_to_ignore[] = {
-             99,  72,  82,  77, '\0',  /* cHRM */
-            104,  73,  83,  84, '\0',  /* hIST */
-            105,  67,  67,  80, '\0',  /* iCCP */
-            105,  84,  88, 116, '\0',  /* iTXt */
-            111,  70,  70, 115, '\0',  /* oFFs */
-            112,  67,  65,  76, '\0',  /* pCAL */
-            112,  72,  89, 115, '\0',  /* pHYs */
-            115,  66,  73,  84, '\0',  /* sBIT */
-            115,  67,  65,  76, '\0',  /* sCAL */
-            115,  80,  76,  84, '\0',  /* sPLT */
-            115,  84,  69,  82, '\0',  /* sTER */
-            116,  69,  88, 116, '\0',  /* tEXt */
-            116,  73,  77,  69, '\0',  /* tIME */
-            122,  84,  88, 116, '\0'   /* zTXt */
-        };
-
-        png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */,
-          chunks_to_ignore, sizeof(chunks_to_ignore)/5);
-    }
-#endif /* PNG_UNKNOWN_CHUNKS_SUPPORTED */
-
-
-    /* instead of doing png_init_io() here, now we set up our callback
-     * functions for progressive decoding */
-
-    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
-      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
-
-
-    /*
-     * may as well enable or disable MMX routines here, if supported;
-     *
-     * to enable all:  mask = png_get_mmx_flagmask (
-     *                   PNG_SELECT_READ | PNG_SELECT_WRITE, &compilerID);
-     *                 flags = png_get_asm_flags (png_ptr);
-     *                 flags |= mask;
-     *                 png_set_asm_flags (png_ptr, flags);
-     *
-     * to disable all:  mask = png_get_mmx_flagmask (
-     *                   PNG_SELECT_READ | PNG_SELECT_WRITE, &compilerID);
-     *                  flags = png_get_asm_flags (png_ptr);
-     *                  flags &= ~mask;
-     *                  png_set_asm_flags (png_ptr, flags);
-     */
-
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__)) && \
-    defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
-    /*
-     * WARNING:  This preprocessor approach means that the following code
-     *           cannot be used with a libpng DLL older than 1.2.0--the
-     *           compiled-in symbols for the new functions will not exist.
-     *           (Could use dlopen() and dlsym() on Unix and corresponding
-     *           calls for Windows, but not portable...)
-     */
-    {
-#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
-        png_uint_32 mmx_disable_mask = 0;
-        png_uint_32 asm_flags, mmx_mask;
-        int compilerID;
-
-        if (mainprog_ptr->nommxfilters)
-            mmx_disable_mask |= ( PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
-                                | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
-                                | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
-                                | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH );
-        if (mainprog_ptr->nommxcombine)
-            mmx_disable_mask |= PNG_ASM_FLAG_MMX_READ_COMBINE_ROW;
-        if (mainprog_ptr->nommxinterlace)
-            mmx_disable_mask |= PNG_ASM_FLAG_MMX_READ_INTERLACE;
-        asm_flags = png_get_asm_flags(png_ptr);
-        png_set_asm_flags(png_ptr, asm_flags & ~mmx_disable_mask);
-
-
-        /* Now query libpng's asm settings, just for yuks.  Note that this
-         * differs from the querying of its *potential* MMX capabilities
-         * in readpng2_version_info(); this is true runtime verification. */
-
-        asm_flags = png_get_asm_flags(png_ptr);
-        mmx_mask = png_get_mmx_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE,
-          &compilerID);
-        if (asm_flags & PNG_ASM_FLAG_MMX_SUPPORT_COMPILED)
-            fprintf(stderr,
-              "  MMX support (%s version) is compiled into libpng\n",
-              compilerID == 1? "MSVC++" :
-              (compilerID == 2? "GNU C" : "unknown"));
-        else
-            fprintf(stderr, "  MMX support is not compiled into libpng\n");
-        fprintf(stderr, "  MMX instructions are %ssupported by CPU\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU)? "" : "not ");
-        fprintf(stderr, "  MMX read support for combining rows is %sabled\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)? "en" : "dis");
-        fprintf(stderr,
-          "  MMX read support for expanding interlacing is %sabled\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_READ_INTERLACE)? "en" : "dis");
-        fprintf(stderr, "  MMX read support for \"sub\" filter is %sabled\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_SUB)? "en" : "dis");
-        fprintf(stderr, "  MMX read support for \"up\" filter is %sabled\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_UP)? "en" : "dis");
-        fprintf(stderr, "  MMX read support for \"avg\" filter is %sabled\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_AVG)? "en" : "dis");
-        fprintf(stderr, "  MMX read support for \"Paeth\" filter is %sabled\n",
-          (asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_PAETH)? "en" : "dis");
-        asm_flags &= (mmx_mask & ~( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \
-                                  | PNG_ASM_FLAG_MMX_READ_INTERLACE    \
-                                  | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
-                                  | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
-                                  | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
-                                  | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ));
-        if (asm_flags)
-            fprintf(stderr,
-              "  additional MMX support is also enabled (0x%02lx)\n",
-              asm_flags);
-#else  /* !PNG_ASSEMBLER_CODE_SUPPORTED */
-        fprintf(stderr, "  MMX querying is disabled in libpng.\n");
-#endif /* ?PNG_ASSEMBLER_CODE_SUPPORTED */
-    }
-#endif
-
-
-    /* make sure we save our pointers for use in readpng2_decode_data() */
-
-    mainprog_ptr->png_ptr = png_ptr;
-    mainprog_ptr->info_ptr = info_ptr;
-
-
-    /* and that's all there is to initialization */
-
-    return 0;
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng (longjmp) problem */
-
-int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* hand off the next chunk of input data to libpng for decoding */
-
-    png_process_data(png_ptr, info_ptr, rawbuf, length);
-
-    return 0;
-}
-
-
-
-
-static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
-{
-    mainprog_info  *mainprog_ptr;
-    int  color_type, bit_depth;
-    double  gamma;
-
-
-    /* setjmp() doesn't make sense here, because we'd either have to exit(),
-     * longjmp() ourselves, or return control to libpng, which doesn't want
-     * to see us again.  By not doing anything here, libpng will instead jump
-     * to readpng2_decode_data(), which can return an error value to the main
-     * program. */
-
-
-    /* retrieve the pointer to our special-purpose struct, using the png_ptr
-     * that libpng passed back to us (i.e., not a global this time--there's
-     * no real difference for a single image, but for a multithreaded browser
-     * decoding several PNG images at the same time, one needs to avoid mixing
-     * up different images' structs) */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-    if (mainprog_ptr == NULL) {         /* we be hosed */
-        fprintf(stderr,
-          "readpng2 error:  main struct not recoverable in info_callback.\n");
-        fflush(stderr);
-        return;
-        /*
-         * Alternatively, we could call our error-handler just like libpng
-         * does, which would effectively terminate the program.  Since this
-         * can only happen if png_ptr gets redirected somewhere odd or the
-         * main PNG struct gets wiped, we're probably toast anyway.  (If
-         * png_ptr itself is NULL, we would not have been called.)
-         */
-    }
-
-
-    /* this is just like in the non-progressive case */
-
-    png_get_IHDR(png_ptr, info_ptr, &mainprog_ptr->width,
-      &mainprog_ptr->height, &bit_depth, &color_type, NULL, NULL, NULL);
-
-
-    /* since we know we've read all of the PNG file's "header" (i.e., up
-     * to IDAT), we can check for a background color here */
-
-    if (mainprog_ptr->need_bgcolor &&
-        png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
-    {
-        png_color_16p pBackground;
-
-        /* it is not obvious from the libpng documentation, but this function
-         * takes a pointer to a pointer, and it always returns valid red,
-         * green and blue values, regardless of color_type: */
-        png_get_bKGD(png_ptr, info_ptr, &pBackground);
-
-        /* however, it always returns the raw bKGD data, regardless of any
-         * bit-depth transformations, so check depth and adjust if necessary */
-        if (bit_depth == 16) {
-            mainprog_ptr->bg_red   = pBackground->red   >> 8;
-            mainprog_ptr->bg_green = pBackground->green >> 8;
-            mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
-        } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-            if (bit_depth == 1)
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                  mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
-            else if (bit_depth == 2)
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                  mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
-            else /* bit_depth == 4 */
-                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                  mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
-        } else {
-            mainprog_ptr->bg_red   = (uch)pBackground->red;
-            mainprog_ptr->bg_green = (uch)pBackground->green;
-            mainprog_ptr->bg_blue  = (uch)pBackground->blue;
-        }
-    }
-
-
-    /* as before, let libpng expand palette images to RGB, low-bit-depth
-     * grayscale images to 8 bits, transparency chunks to full alpha channel;
-     * strip 16-bit-per-sample images to 8 bits per sample; and convert
-     * grayscale to RGB[A] */
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_expand(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-        png_set_expand(png_ptr);
-    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-        png_set_expand(png_ptr);
-    if (bit_depth == 16)
-        png_set_strip_16(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-        png_set_gray_to_rgb(png_ptr);
-
-
-    /* Unlike the basic viewer, which was designed to operate on local files,
-     * this program is intended to simulate a web browser--even though we
-     * actually read from a local file, too.  But because we are pretending
-     * that most of the images originate on the Internet, we follow the recom-
-     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
-     * chunk) as existing in the sRGB color space.  That is, we assume that
-     * such images have a file gamma of 0.45455, which corresponds to a PC-like
-     * display system.  This change in assumptions will have no effect on a
-     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
-     * identity lookup table, it will darken unlabelled images, which effec-
-     * tively favors images from PC-like systems over those originating on
-     * the local platform.  Note that mainprog_ptr->display_exponent is the
-     * "gamma" value for the entire display system, i.e., the product of
-     * LUT_exponent and CRT_exponent. */
-
-    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
-        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
-    else
-        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
-
-
-    /* we'll let libpng expand interlaced images, too */
-
-    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
-
-
-    /* all transformations have been registered; now update info_ptr data and
-     * then get rowbytes and channels */
-
-    png_read_update_info(png_ptr, info_ptr);
-
-    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
-    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
-
-
-    /* Call the main program to allocate memory for the image buffer and
-     * initialize windows and whatnot.  (The old-style function-pointer
-     * invocation is used for compatibility with a few supposedly ANSI
-     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
-
-    (*mainprog_ptr->mainprog_init)();
-
-
-    /* and that takes care of initialization */
-
-    return;
-}
-
-
-
-
-
-static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
-                                  png_uint_32 row_num, int pass)
-{
-    mainprog_info  *mainprog_ptr;
-
-
-    /* first check whether the row differs from the previous pass; if not,
-     * nothing to combine or display */
-
-    if (!new_row)
-        return;
-
-
-    /* retrieve the pointer to our special-purpose struct so we can access
-     * the old rows and image-display callback function */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-
-    /* save the pass number for optional use by the front end */
-
-    mainprog_ptr->pass = pass;
-
-
-    /* have libpng either combine the new row data with the existing row data
-     * from previous passes (if interlaced) or else just copy the new row
-     * into the main program's image buffer */
-
-    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
-      new_row);
-
-
-    /* finally, call the display routine in the main program with the number
-     * of the row we just updated */
-
-    (*mainprog_ptr->mainprog_display_row)(row_num);
-
-
-    /* and we're ready for more */
-
-    return;
-}
-
-
-
-
-
-static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
-{
-    mainprog_info  *mainprog_ptr;
-
-
-    /* retrieve the pointer to our special-purpose struct */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-
-    /* let the main program know that it should flush any buffered image
-     * data to the display now and set a "done" flag or whatever, but note
-     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
-     * NOT call readpng2_cleanup() either here or in the finish_display()
-     * routine; wait until control returns to the main program via
-     * readpng2_decode_data() */
-
-    (*mainprog_ptr->mainprog_finish_display)();
-
-
-    /* all done */
-
-    return;
-}
-
-
-
-
-
-void readpng2_cleanup(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-    if (png_ptr && info_ptr)
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
-    mainprog_ptr->png_ptr = NULL;
-    mainprog_ptr->info_ptr = NULL;
-}
-
-
-
-
-
-static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
-{
-    mainprog_info  *mainprog_ptr;
-
-    /* This function, aside from the extra step of retrieving the "error
-     * pointer" (below) and the fact that it exists within the application
-     * rather than within libpng, is essentially identical to libpng's
-     * default error handler.  The second point is critical:  since both
-     * setjmp() and longjmp() are called from the same code, they are
-     * guaranteed to have compatible notions of how big a jmp_buf is,
-     * regardless of whether _BSD_SOURCE or anything else has (or has not)
-     * been defined. */
-
-    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
-    fflush(stderr);
-
-    mainprog_ptr = png_get_error_ptr(png_ptr);
-    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
-        fprintf(stderr,
-          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
-        fflush(stderr);
-        exit(99);
-    }
-
-    longjmp(mainprog_ptr->jmpbuf, 1);
-}
diff --git a/contrib/gregbook/readpng2.h b/contrib/gregbook/readpng2.h
deleted file mode 100644
index fbfffb4..0000000
--- a/contrib/gregbook/readpng2.h
+++ /dev/null
@@ -1,121 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                 readpng2.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-enum rpng2_states {
-    kPreInit = 0,
-    kWindowInit,
-    kDone
-};
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-typedef struct _mainprog_info {
-    double display_exponent;
-    ulg width;
-    ulg height;
-    void *png_ptr;
-    void *info_ptr;
-    void (*mainprog_init)(void);
-    void (*mainprog_display_row)(ulg row_num);
-    void (*mainprog_finish_display)(void);
-    uch *image_data;
-    uch **row_pointers;
-    jmp_buf jmpbuf;
-    int passes;              /* not used */
-    int pass;
-    int rowbytes;
-    int channels;
-    int need_bgcolor;
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-    int nommxfilters;
-    int nommxcombine;
-    int nommxinterlace;
-#endif
-    int state;
-    uch bg_red;
-    uch bg_green;
-    uch bg_blue;
-} mainprog_info;
-
-
-/* prototypes for public functions in readpng2.c */
-
-void readpng2_version_info(void);
-
-int readpng2_check_sig(uch *sig, int num);
-
-int readpng2_init(mainprog_info *mainprog_ptr);
-
-int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
-
-void readpng2_cleanup(mainprog_info *mainprog_ptr);
diff --git a/contrib/gregbook/readppm.c b/contrib/gregbook/readppm.c
deleted file mode 100644
index be9a56d..0000000
--- a/contrib/gregbook/readppm.c
+++ /dev/null
@@ -1,179 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readppm.c
-
-  ---------------------------------------------------------------------------
-
-   This is a special-purpose replacement for readpng.c that allows binary
-   PPM files to be used in place of PNG images.
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "readpng.h"    /* typedefs, common macros, public prototypes */
-
-
-ulg  width, height;
-int  bit_depth, color_type, channels;
-uch  *image_data = NULL;
-FILE *saved_infile;
-
-
-void readpng_version_info()
-{
-    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
-}
-
-
-/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
-{
-    static uch ppmline[256];
-    int maxval;
-
-
-    saved_infile = infile;
-
-    fgets(ppmline, 256, infile);
-    if (ppmline[0] != 'P' || ppmline[1] != '6') {
-        fprintf(stderr, "ERROR:  not a PPM file\n");
-        return 1;
-    }
-    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
-    if (ppmline[1] == '6') {
-        color_type = 2;
-        channels = 3;
-    } else if (ppmline[1] == '8') {
-        color_type = 6;
-        channels = 4;
-    } else /* if (ppmline[1] == '5') */ {
-        color_type = 0;
-        channels = 1;
-    }
-
-    do {
-        fgets(ppmline, 256, infile);
-    } while (ppmline[0] == '#');
-    sscanf(ppmline, "%lu %lu", &width, &height);
-
-    do {
-        fgets(ppmline, 256, infile);
-    } while (ppmline[0] == '#');
-    sscanf(ppmline, "%d", &maxval);
-    if (maxval != 255) {
-        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
-        return 2;
-    }
-    bit_depth = 8;
-
-    *pWidth = width;
-    *pHeight = height;
-
-    return 0;
-}
-
-
-
-
-/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
-
-int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
-{
-    return 1;
-}
-
-
-
-
-/* display_exponent == LUT_exponent * CRT_exponent */
-
-uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
-{
-    ulg  rowbytes;
-
-
-    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
-     * transparency chunks to full alpha channel; strip 16-bit-per-sample
-     * images to 8 bits per sample; and convert grayscale to RGB[A] */
-
-    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
-
-    *pRowbytes = rowbytes = channels*width;
-    *pChannels = channels;
-
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-        return NULL;
-    }
-
-    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
-
-
-    /* now we can go ahead and just read the whole image */
-
-    fread(image_data, 1L, rowbytes*height, saved_infile);
-
-
-    return image_data;
-}
-
-
-void readpng_cleanup(int free_image_data)
-{
-    if (free_image_data && image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-}
diff --git a/contrib/gregbook/rpng-win.c b/contrib/gregbook/rpng-win.c
deleted file mode 100644
index 2020961..0000000
--- a/contrib/gregbook/rpng-win.c
+++ /dev/null
@@ -1,684 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                             rpng-win.c
-
-   This program decodes and displays PNG images, with gamma correction and
-   optionally with a user-specified background color (in case the image has
-   transparency).  It is very nearly the most basic PNG viewer possible.
-   This version is for 32-bit Windows; it may compile under 16-bit Windows
-   with a little tweaking (or maybe not).
-
-   to do:
-    - handle quoted command-line args (especially filenames with spaces)
-    - have minimum window width:  oh well
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.00:  initial public release
-    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
-              match; switched to png_jmpbuf() macro
-    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
-              command-line parsing bug
-    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed improper display of usage screen on PNG error(s)
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng-win"
-#define LONGNAME  "Simple PNG Viewer for Windows"
-#define VERSION   "2.01 of 16 March 2008"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <windows.h>
-#include <conio.h>      /* only for _getch() */
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-/* local prototypes */
-static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
-static int        rpng_win_display_image(void);
-static void       rpng_win_cleanup(void);
-LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
-
-
-static char titlebar[1024];
-static char *progname = PROGNAME;
-static char *appname = LONGNAME;
-static char *filename;
-static FILE *infile;
-
-static char *bgstr;
-static uch bg_red=0, bg_green=0, bg_blue=0;
-
-static double display_exponent;
-
-static ulg image_width, image_height, image_rowbytes;
-static int image_channels;
-static uch *image_data;
-
-/* Windows-specific variables */
-static ulg wimage_rowbytes;
-static uch *dib;
-static uch *wimage_data;
-static BITMAPINFOHEADER *bmih;
-
-static HWND global_hwnd;
-
-
-
-
-int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
-{
-    char *args[1024];                 /* arbitrary limit, but should suffice */
-    char *p, *q, **argv = args;
-    int argc = 0;
-    int rc, alen, flen;
-    int error = 0;
-    int have_bg = FALSE;
-    double LUT_exponent;              /* just the lookup table */
-    double CRT_exponent = 2.2;        /* just the monitor */
-    double default_display_exponent;  /* whole display system */
-    MSG msg;
-
-
-    filename = (char *)NULL;
-
-
-    /* First reenable console output, which normally goes to the bit bucket
-     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
-     * incantation. */
-
-    AllocConsole();
-    freopen("CONOUT$", "a", stderr);
-    freopen("CONOUT$", "a", stdout);
-
-
-    /* Next set the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities.  And
-     * yes, these ifdefs are completely wasted in a Windows program... */
-
-#if defined(NeXT)
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to get the
-     * "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        display_exponent = atof(p);
-    else
-        display_exponent = default_display_exponent;
-
-
-    /* Windows really hates command lines, so we have to set up our own argv.
-     * Note that we do NOT bother with quoted arguments here, so don't use
-     * filenames with spaces in 'em! */
-
-    argv[argc++] = PROGNAME;
-    p = cmd;
-    for (;;) {
-        if (*p == ' ')
-            while (*++p == ' ')
-                ;
-        /* now p points at the first non-space after some spaces */
-        if (*p == '\0')
-            break;    /* nothing after the spaces:  done */
-        argv[argc++] = q = p;
-        while (*q && *q != ' ')
-            ++q;
-        /* now q points at a space or the end of the string */
-        if (*q == '\0')
-            break;    /* last argv already terminated; quit */
-        *q = '\0';    /* change space to terminator */
-        p = q + 1;
-    }
-    argv[argc] = NULL;   /* terminate the argv array itself */
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                display_exponent = atof(*argv);
-                if (display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else
-                    have_bg = TRUE;
-            }
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-        int ch;
-
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images\n"
-          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
-          "Press Q or Esc to quit this usage screen.\n"
-          "\n", PROGNAME, default_display_exponent);
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
-            switch (rc) {
-                case 1:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] is not a PNG file: incorrect signature\n",
-                      filename);
-                    break;
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng_init() error\n");
-                    break;
-            }
-            ++error;
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-        int ch;
-
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-        exit(2);
-    } else {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-        fprintf(stderr,
-          "\n   [console window:  closing this window will terminate %s]\n\n",
-          PROGNAME);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* if the user didn't specify a background color on the command line,
-     * check for one in the PNG file--if not, the initialized values of 0
-     * (black) will be used */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        bg_red   = (uch)r;
-        bg_green = (uch)g;
-        bg_blue  = (uch)b;
-    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
-        readpng_cleanup(TRUE);
-        fprintf(stderr, PROGNAME
-          ":  libpng error while checking for background color\n");
-        exit(2);
-    }
-
-
-    /* do the basic Windows initialization stuff, make the window and fill it
-     * with the background color */
-
-    if (rpng_win_create_window(hInst, showmode))
-        exit(2);
-
-
-    /* decode the image, all at once */
-
-    Trace((stderr, "calling readpng_get_image()\n"))
-    image_data = readpng_get_image(display_exponent, &image_channels,
-      &image_rowbytes);
-    Trace((stderr, "done with readpng_get_image()\n"))
-
-
-    /* done with PNG file, so clean up to minimize memory usage (but do NOT
-     * nuke image_data!) */
-
-    readpng_cleanup(FALSE);
-    fclose(infile);
-
-    if (!image_data) {
-        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
-        exit(3);
-    }
-
-
-    /* display image (composite with background if requested) */
-
-    Trace((stderr, "calling rpng_win_display_image()\n"))
-    if (rpng_win_display_image()) {
-        free(image_data);
-        exit(4);
-    }
-    Trace((stderr, "done with rpng_win_display_image()\n"))
-
-
-    /* wait for the user to tell us when to quit */
-
-    printf(
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
-    fflush(stdout);
-
-    while (GetMessage(&msg, NULL, 0, 0)) {
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-    }
-
-
-    /* OK, we're done:  clean up all image and Windows resources and go away */
-
-    rpng_win_cleanup();
-
-    return msg.wParam;
-}
-
-
-
-
-
-static int rpng_win_create_window(HINSTANCE hInst, int showmode)
-{
-    uch *dest;
-    int extra_width, extra_height;
-    ulg i, j;
-    WNDCLASSEX wndclass;
-
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the display-specific version of the image (round up
-    to multiple of 4 for Windows DIB).
-  ---------------------------------------------------------------------------*/
-
-    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
-
-    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
-                              wimage_rowbytes*image_height)))
-    {
-        return 4;   /* fail */
-    }
-
-/*---------------------------------------------------------------------------
-    Initialize the DIB.  Negative height means to use top-down BMP ordering
-    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
-    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
-    directly => wimage_data begins immediately after BMP header.
-  ---------------------------------------------------------------------------*/
-
-    memset(dib, 0, sizeof(BITMAPINFOHEADER));
-    bmih = (BITMAPINFOHEADER *)dib;
-    bmih->biSize = sizeof(BITMAPINFOHEADER);
-    bmih->biWidth = image_width;
-    bmih->biHeight = -((long)image_height);
-    bmih->biPlanes = 1;
-    bmih->biBitCount = 24;
-    bmih->biCompression = 0;
-    wimage_data = dib + sizeof(BITMAPINFOHEADER);
-
-/*---------------------------------------------------------------------------
-    Fill in background color (black by default); data are in BGR order.
-  ---------------------------------------------------------------------------*/
-
-    for (j = 0;  j < image_height;  ++j) {
-        dest = wimage_data + j*wimage_rowbytes;
-        for (i = image_width;  i > 0;  --i) {
-            *dest++ = bg_blue;
-            *dest++ = bg_green;
-            *dest++ = bg_red;
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Set the window parameters.
-  ---------------------------------------------------------------------------*/
-
-    memset(&wndclass, 0, sizeof(wndclass));
-
-    wndclass.cbSize = sizeof(wndclass);
-    wndclass.style = CS_HREDRAW | CS_VREDRAW;
-    wndclass.lpfnWndProc = rpng_win_wndproc;
-    wndclass.hInstance = hInst;
-    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
-    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
-    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
-    wndclass.lpszMenuName = NULL;
-    wndclass.lpszClassName = progname;
-    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
-
-    RegisterClassEx(&wndclass);
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
-                      GetSystemMetrics(SM_CXDLGFRAME));
-    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
-                      GetSystemMetrics(SM_CYDLGFRAME)) +
-                      GetSystemMetrics(SM_CYCAPTION);
-
-    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
-      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
-      image_height+extra_height, NULL, NULL, hInst, NULL);
-
-    ShowWindow(global_hwnd, showmode);
-    UpdateWindow(global_hwnd);
-
-    return 0;
-
-} /* end function rpng_win_create_window() */
-
-
-
-
-
-static int rpng_win_display_image()
-{
-    uch *src, *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow;
-    RECT rect;
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      image_channels))
-    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
-      image_width, image_rowbytes, wimage_rowbytes))
-
-
-/*---------------------------------------------------------------------------
-    Blast image data to buffer.  This whole routine takes place before the
-    message loop begins, so there's no real point in any pseudo-progressive
-    display...
-  ---------------------------------------------------------------------------*/
-
-    for (lastrow = row = 0;  row < image_height;  ++row) {
-        src = image_data + row*image_rowbytes;
-        dest = wimage_data + row*wimage_rowbytes;
-        if (image_channels == 3) {
-            for (i = image_width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                *dest++ = b;
-                *dest++ = g;   /* note reverse order */
-                *dest++ = r;
-            }
-        } else /* if (image_channels == 4) */ {
-            for (i = image_width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (a == 255) {
-                    *dest++ = b;
-                    *dest++ = g;
-                    *dest++ = r;
-                } else if (a == 0) {
-                    *dest++ = bg_blue;
-                    *dest++ = bg_green;
-                    *dest++ = bg_red;
-                } else {
-                    /* this macro (copied from png.h) composites the
-                     * foreground and background values and puts the
-                     * result into the first argument; there are no
-                     * side effects with the first argument */
-                    alpha_composite(*dest++, b, a, bg_blue);
-                    alpha_composite(*dest++, g, a, bg_green);
-                    alpha_composite(*dest++, r, a, bg_red);
-                }
-            }
-        }
-        /* display after every 16 lines */
-        if (((row+1) & 0xf) == 0) {
-            rect.left = 0L;
-            rect.top = (LONG)lastrow;
-            rect.right = (LONG)image_width;      /* possibly off by one? */
-            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
-            InvalidateRect(global_hwnd, &rect, FALSE);
-            UpdateWindow(global_hwnd);     /* similar to XFlush() */
-            lastrow = row + 1;
-        }
-    }
-
-    Trace((stderr, "calling final image-flush routine\n"))
-    if (lastrow < image_height) {
-        rect.left = 0L;
-        rect.top = (LONG)lastrow;
-        rect.right = (LONG)image_width;      /* possibly off by one? */
-        rect.bottom = (LONG)image_height;    /* possibly off by one? */
-        InvalidateRect(global_hwnd, &rect, FALSE);
-        UpdateWindow(global_hwnd);     /* similar to XFlush() */
-    }
-
-/*
-    last param determines whether or not background is wiped before paint
-    InvalidateRect(global_hwnd, NULL, TRUE);
-    UpdateWindow(global_hwnd);
- */
-
-    return 0;
-}
-
-
-
-
-
-static void rpng_win_cleanup()
-{
-    if (image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (dib) {
-        free(dib);
-        dib = NULL;
-    }
-}
-
-
-
-
-
-LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
-{
-    HDC         hdc;
-    PAINTSTRUCT ps;
-    int rc;
-
-    switch (iMsg) {
-        case WM_CREATE:
-            /* one-time processing here, if any */
-            return 0;
-
-        case WM_PAINT:
-            hdc = BeginPaint(hwnd, &ps);
-                    /*                    dest                          */
-            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
-                    /*                    source                        */
-                                    0, 0, image_width, image_height,
-                                    wimage_data, (BITMAPINFO *)bmih,
-                    /*              iUsage: no clue                     */
-                                    0, SRCCOPY);
-            EndPaint(hwnd, &ps);
-            return 0;
-
-        /* wait for the user to tell us when to quit */
-        case WM_CHAR:
-            switch (wP) {      /* only need one, so ignore repeat count */
-                case 'q':
-                case 'Q':
-                case 0x1B:     /* Esc key */
-                    PostQuitMessage(0);
-            }
-            return 0;
-
-        case WM_LBUTTONDOWN:   /* another way of quitting */
-        case WM_DESTROY:
-            PostQuitMessage(0);
-            return 0;
-    }
-
-    return DefWindowProc(hwnd, iMsg, wP, lP);
-}
diff --git a/contrib/gregbook/rpng-x.c b/contrib/gregbook/rpng-x.c
deleted file mode 100644
index 0a98170..0000000
--- a/contrib/gregbook/rpng-x.c
+++ /dev/null
@@ -1,904 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                               rpng-x.c
-
-   This program decodes and displays PNG images, with gamma correction and
-   optionally with a user-specified background color (in case the image has
-   transparency).  It is very nearly the most basic PNG viewer possible.
-   This version is for the X Window System (tested by author under Unix and
-   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
-
-   to do:
-    - 8-bit (colormapped) X support
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
-              match; switched to png_jmpbuf() macro
-    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
-    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
-              command-line parsing bug
-    - 1.12:  fixed some small X memory leaks (thanks to François Petitjean)
-    - 1.13:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
-    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed improper display of usage screen on PNG error(s)
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng-x"
-#define LONGNAME  "Simple PNG Viewer for X"
-#define VERSION   "2.01 of 16 March 2008"
-#define RESNAME   "rpng"	/* our X resource application name */
-#define RESCLASS  "Rpng"	/* our X resource class name */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <X11/Xlib.h>
-#include <X11/Xutil.h>
-#include <X11/Xos.h>
-#include <X11/keysym.h>
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-#include "readpng.h"   /* typedefs, common macros, readpng prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-/* local prototypes */
-static int  rpng_x_create_window(void);
-static int  rpng_x_display_image(void);
-static void rpng_x_cleanup(void);
-static int  rpng_x_msb(ulg u32val);
-
-
-static char titlebar[1024], *window_name = titlebar;
-static char *appname = LONGNAME;
-static char *icon_name = PROGNAME;
-static char *res_name = RESNAME;
-static char *res_class = RESCLASS;
-static char *filename;
-static FILE *infile;
-
-static char *bgstr;
-static uch bg_red=0, bg_green=0, bg_blue=0;
-
-static double display_exponent;
-
-static ulg image_width, image_height, image_rowbytes;
-static int image_channels;
-static uch *image_data;
-
-/* X-specific variables */
-static char *displayname;
-static XImage *ximage;
-static Display *display;
-static int depth;
-static Visual *visual;
-static XVisualInfo *visual_list;
-static int RShift, GShift, BShift;
-static ulg RMask, GMask, BMask;
-static Window window;
-static GC gc;
-static Colormap colormap;
-
-static int have_nondefault_visual = FALSE;
-static int have_colormap = FALSE;
-static int have_window = FALSE;
-static int have_gc = FALSE;
-/*
-ulg numcolors=0, pixels[256];
-ush reds[256], greens[256], blues[256];
- */
-
-
-
-
-int main(int argc, char **argv)
-{
-#ifdef sgi
-    char tmpline[80];
-#endif
-    char *p;
-    int rc, alen, flen;
-    int error = 0;
-    int have_bg = FALSE;
-    double LUT_exponent;               /* just the lookup table */
-    double CRT_exponent = 2.2;         /* just the monitor */
-    double default_display_exponent;   /* whole display system */
-    XEvent e;
-    KeySym k;
-
-
-    displayname = (char *)NULL;
-    filename = (char *)NULL;
-
-
-    /* First set the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities. */
-
-#if defined(NeXT)
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to get the
-     * "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        display_exponent = atof(p);
-    else
-        display_exponent = default_display_exponent;
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-display", 2)) {
-            if (!*++argv)
-                ++error;
-            else
-                displayname = *argv;
-        } else if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                display_exponent = atof(*argv);
-                if (display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error; 
-                else 
-                    have_bg = TRUE;
-            }
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-        readpng_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
-          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images\n"
-          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME, default_display_exponent);
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
-            switch (rc) {
-                case 1:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] is not a PNG file: incorrect signature\n",
-                      filename);
-                    break;
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng_init() error\n");
-                    break;
-            }
-            ++error;
-        } else {
-            display = XOpenDisplay(displayname);
-            if (!display) {
-                readpng_cleanup(TRUE);
-                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
-                  displayname? displayname : "default");
-                ++error;
-            }
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-        exit(2);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* if the user didn't specify a background color on the command line,
-     * check for one in the PNG file--if not, the initialized values of 0
-     * (black) will be used */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        bg_red   = (uch)r;
-        bg_green = (uch)g;
-        bg_blue  = (uch)b;
-    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
-        readpng_cleanup(TRUE);
-        fprintf(stderr, PROGNAME
-          ":  libpng error while checking for background color\n");
-        exit(2);
-    }
-
-
-    /* do the basic X initialization stuff, make the window and fill it
-     * with the background color */
-
-    if (rpng_x_create_window())
-        exit(2);
-
-
-    /* decode the image, all at once */
-
-    Trace((stderr, "calling readpng_get_image()\n"))
-    image_data = readpng_get_image(display_exponent, &image_channels,
-      &image_rowbytes);
-    Trace((stderr, "done with readpng_get_image()\n"))
-
-
-    /* done with PNG file, so clean up to minimize memory usage (but do NOT
-     * nuke image_data!) */
-
-    readpng_cleanup(FALSE);
-    fclose(infile);
-
-    if (!image_data) {
-        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
-        exit(3);
-    }
-
-
-    /* display image (composite with background if requested) */
-
-    Trace((stderr, "calling rpng_x_display_image()\n"))
-    if (rpng_x_display_image()) {
-        free(image_data);
-        exit(4);
-    }
-    Trace((stderr, "done with rpng_x_display_image()\n"))
-
-
-    /* wait for the user to tell us when to quit */
-
-    printf(
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
-    fflush(stdout);
-
-    do
-        XNextEvent(display, &e);
-    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
-           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
-             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
-
-
-    /* OK, we're done:  clean up all image and X resources and go away */
-
-    rpng_x_cleanup();
-
-    return 0;
-}
-
-
-
-
-
-static int rpng_x_create_window(void)
-{
-    uch *xdata;
-    int need_colormap = FALSE;
-    int screen, pad;
-    ulg bg_pixel = 0L;
-    ulg attrmask;
-    Window root;
-    XEvent e;
-    XGCValues gcvalues;
-    XSetWindowAttributes attr;
-    XTextProperty windowName, *pWindowName = &windowName;
-    XTextProperty iconName, *pIconName = &iconName;
-    XVisualInfo visual_info;
-    XSizeHints *size_hints;
-    XWMHints *wm_hints;
-    XClassHint *class_hints;
-
-
-    screen = DefaultScreen(display);
-    depth = DisplayPlanes(display, screen);
-    root = RootWindow(display, screen);
-
-#ifdef DEBUG
-    XSynchronize(display, True);
-#endif
-
-#if 0
-/* GRR:  add 8-bit support */
-    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
-        fprintf(stderr,
-          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
-          depth);
-        return 2;
-    }
-
-    XMatchVisualInfo(display, screen, depth,
-      (depth == 8)? PseudoColor : TrueColor, &visual_info);
-    visual = visual_info.visual;
-#else
-    if (depth != 16 && depth != 24 && depth != 32) {
-        int visuals_matched = 0;
-
-        Trace((stderr, "default depth is %d:  checking other visuals\n",
-          depth))
-
-        /* 24-bit first */
-        visual_info.screen = screen;
-        visual_info.depth = 24;
-        visual_list = XGetVisualInfo(display,
-          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
-        if (visuals_matched == 0) {
-/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
-            fprintf(stderr, "default screen depth %d not supported, and no"
-              " 24-bit visuals found\n", depth);
-            return 2;
-        }
-        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
-          visuals_matched))
-        visual = visual_list[0].visual;
-        depth = visual_list[0].depth;
-/*
-        colormap_size = visual_list[0].colormap_size;
-        visual_class = visual->class;
-        visualID = XVisualIDFromVisual(visual);
- */
-        have_nondefault_visual = TRUE;
-        need_colormap = TRUE;
-    } else {
-        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
-        visual = visual_info.visual;
-    }
-#endif
-
-    RMask = visual->red_mask;
-    GMask = visual->green_mask;
-    BMask = visual->blue_mask;
-
-/* GRR:  add/check 8-bit support */
-    if (depth == 8 || need_colormap) {
-        colormap = XCreateColormap(display, root, visual, AllocNone);
-        if (!colormap) {
-            fprintf(stderr, "XCreateColormap() failed\n");
-            return 2;
-        }
-        have_colormap = TRUE;
-    }
-    if (depth == 15 || depth == 16) {
-        RShift = 15 - rpng_x_msb(RMask);    /* these are right-shifts */
-        GShift = 15 - rpng_x_msb(GMask);
-        BShift = 15 - rpng_x_msb(BMask);
-    } else if (depth > 16) {
-#define NO_24BIT_MASKS
-#ifdef NO_24BIT_MASKS
-        RShift = rpng_x_msb(RMask) - 7;     /* these are left-shifts */
-        GShift = rpng_x_msb(GMask) - 7;
-        BShift = rpng_x_msb(BMask) - 7;
-#else
-        RShift = 7 - rpng_x_msb(RMask);     /* these are right-shifts, too */
-        GShift = 7 - rpng_x_msb(GMask);
-        BShift = 7 - rpng_x_msb(BMask);
-#endif
-    }
-    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
-        fprintf(stderr, "rpng internal logic error:  negative X shift(s)!\n");
-        return 2;
-    }
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    attr.backing_store = Always;
-    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
-    attrmask = CWBackingStore | CWEventMask;
-    if (have_nondefault_visual) {
-        attr.colormap = colormap;
-        attr.background_pixel = 0;
-        attr.border_pixel = 1;
-        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
-    }
-
-    window = XCreateWindow(display, root, 0, 0, image_width, image_height, 0,
-      depth, InputOutput, visual, attrmask, &attr);
-
-    if (window == None) {
-        fprintf(stderr, "XCreateWindow() failed\n");
-        return 2;
-    } else
-        have_window = TRUE;
-
-    if (depth == 8)
-        XSetWindowColormap(display, window, colormap);
-
-    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
-        pWindowName = NULL;
-    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
-        pIconName = NULL;
-
-    /* OK if any hints allocation fails; XSetWMProperties() allows NULLs */
-
-    if ((size_hints = XAllocSizeHints()) != NULL) {
-        /* window will not be resizable */
-        size_hints->flags = PMinSize | PMaxSize;
-        size_hints->min_width = size_hints->max_width = (int)image_width;
-        size_hints->min_height = size_hints->max_height = (int)image_height;
-    }
-
-    if ((wm_hints = XAllocWMHints()) != NULL) {
-        wm_hints->initial_state = NormalState;
-        wm_hints->input = True;
-     /* wm_hints->icon_pixmap = icon_pixmap; */
-        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
-    }
-
-    if ((class_hints = XAllocClassHint()) != NULL) {
-        class_hints->res_name = res_name;
-        class_hints->res_class = res_class;
-    }
-
-    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
-      size_hints, wm_hints, class_hints);
-
-    /* various properties and hints no longer needed; free memory */
-    if (pWindowName)
-       XFree(pWindowName->value);
-    if (pIconName)
-       XFree(pIconName->value);
-    if (size_hints)
-        XFree(size_hints);
-    if (wm_hints)
-       XFree(wm_hints);
-    if (class_hints)
-       XFree(class_hints);
-
-    XMapWindow(display, window);
-
-    gc = XCreateGC(display, window, 0, &gcvalues);
-    have_gc = TRUE;
-
-/*---------------------------------------------------------------------------
-    Fill window with the specified background color.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        bg_pixel = ((ulg)bg_red   << RShift) |
-                   ((ulg)bg_green << GShift) |
-                   ((ulg)bg_blue  << BShift);
-    } else if (depth == 16) {
-        bg_pixel = ((((ulg)bg_red   << 8) >> RShift) & RMask) |
-                   ((((ulg)bg_green << 8) >> GShift) & GMask) |
-                   ((((ulg)bg_blue  << 8) >> BShift) & BMask);
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    XSetForeground(display, gc, bg_pixel);
-    XFillRectangle(display, window, gc, 0, 0, image_width, image_height);
-
-/*---------------------------------------------------------------------------
-    Wait for first Expose event to do any drawing, then flush.
-  ---------------------------------------------------------------------------*/
-
-    do
-        XNextEvent(display, &e);
-    while (e.type != Expose || e.xexpose.count);
-
-    XFlush(display);
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the X- and display-specific version of the image.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        xdata = (uch *)malloc(4*image_width*image_height);
-        pad = 32;
-    } else if (depth == 16) {
-        xdata = (uch *)malloc(2*image_width*image_height);
-        pad = 16;
-    } else /* depth == 8 */ {
-        xdata = (uch *)malloc(image_width*image_height);
-        pad = 8;
-    }
-
-    if (!xdata) {
-        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
-        return 4;
-    }
-
-    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
-      (char *)xdata, image_width, image_height, pad, 0);
-
-    if (!ximage) {
-        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
-        free(xdata);
-        return 3;
-    }
-
-    /* to avoid testing the byte order every pixel (or doubling the size of
-     * the drawing routine with a giant if-test), we arbitrarily set the byte
-     * order to MSBFirst and let Xlib worry about inverting things on little-
-     * endian machines (like Linux/x86, old VAXen, etc.)--this is not the most
-     * efficient approach (the giant if-test would be better), but in the
-     * interest of clarity, we take the easy way out... */
-
-    ximage->byte_order = MSBFirst;
-
-    return 0;
-
-} /* end function rpng_x_create_window() */
-
-
-
-
-
-static int rpng_x_display_image(void)
-{
-    uch *src;
-    char *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow = 0;
-    ulg pixel;
-    int ximage_rowbytes = ximage->bytes_per_line;
-/*  int bpp = ximage->bits_per_pixel;  */
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      image_channels))
-    Trace((stderr, "   (width = %ld, rowbytes = %ld, ximage_rowbytes = %d)\n",
-      image_width, image_rowbytes, ximage_rowbytes))
-    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
-    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
-      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-
-        for (lastrow = row = 0;  row < image_height;  ++row) {
-            src = image_data + row*image_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (image_channels == 3) {
-                for (i = image_width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-#ifdef NO_24BIT_MASKS
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    /* GRR BUG:  this assumes bpp == 32, but may be 24: */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-#else
-                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
-                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
-                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
-                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-#endif
-                }
-            } else /* if (image_channels == 4) */ {
-                for (i = image_width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (a == 255) {
-                        red   = r;
-                        green = g;
-                        blue  = b;
-                    } else if (a == 0) {
-                        red   = bg_red;
-                        green = bg_green;
-                        blue  = bg_blue;
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result into the
-                         * first argument */
-                        alpha_composite(red,   r, a, bg_red);
-                        alpha_composite(green, g, a, bg_green);
-                        alpha_composite(blue,  b, a, bg_blue);
-                    }
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, image_width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        for (lastrow = row = 0;  row < image_height;  ++row) {
-            src = image_data + row*image_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (image_channels == 3) {
-                for (i = image_width;  i > 0;  --i) {
-                    red   = ((ush)(*src) << 8);
-                    ++src;
-                    green = ((ush)(*src) << 8);
-                    ++src;
-                    blue  = ((ush)(*src) << 8);
-                    ++src;
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            } else /* if (image_channels == 4) */ {
-                for (i = image_width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (a == 255) {
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    } else if (a == 0) {
-                        red   = ((ush)bg_red   << 8);
-                        green = ((ush)bg_green << 8);
-                        blue  = ((ush)bg_blue  << 8);
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result back into
-                         * the first argument (== fg byte here:  safe) */
-                        alpha_composite(r, r, a, bg_red);
-                        alpha_composite(g, g, a, bg_green);
-                        alpha_composite(b, b, a, bg_blue);
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    }
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, image_width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    Trace((stderr, "calling final XPutImage()\n"))
-    if (lastrow < image_height) {
-        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-          (int)lastrow, image_width, image_height-lastrow);
-        XFlush(display);
-    }
-
-    return 0;
-}
-
-
-
-
-static void rpng_x_cleanup(void)
-{
-    if (image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (ximage) {
-        if (ximage->data) {
-            free(ximage->data);           /* we allocated it, so we free it */
-            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
-        }
-        XDestroyImage(ximage);
-        ximage = NULL;
-    }
-
-    if (have_gc)
-        XFreeGC(display, gc);
-
-    if (have_window)
-        XDestroyWindow(display, window);
-
-    if (have_colormap)
-        XFreeColormap(display, colormap);
-
-    if (have_nondefault_visual)
-        XFree(visual_list);
-}
-
-
-
-
-
-static int rpng_x_msb(ulg u32val)
-{
-    int i;
-
-    for (i = 31;  i >= 0;  --i) {
-        if (u32val & 0x80000000L)
-            break;
-        u32val <<= 1;
-    }
-    return i;
-}
diff --git a/contrib/gregbook/rpng2-win.c b/contrib/gregbook/rpng2-win.c
deleted file mode 100644
index 9f7ad78..0000000
--- a/contrib/gregbook/rpng2-win.c
+++ /dev/null
@@ -1,1225 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                rpng2-win.c
-
-   This program decodes and displays PNG files progressively, as if it were
-   a web browser (though the front end is only set up to read from files).
-   It supports gamma correction, user-specified background colors, and user-
-   specified background patterns (for transparent images).  This version is
-   for 32-bit Windows; it may compile under 16-bit Windows with a little
-   tweaking (or maybe not).  Thanks to Adam Costello and Pieter S. van der
-   Meulen for the "diamond" and "radial waves" patterns, respectively.
-
-   to do (someday, maybe):
-    - handle quoted command-line args (especially filenames with spaces)
-    - finish resizable checkerboard-gradient (sizes 4-128?)
-    - use %.1023s to simplify truncation of title-bar string?
-    - have minimum window width:  oh well
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  fixed cut-and-paste error in usage screen (oops...)
-    - 1.03:  modified to allow abbreviated options
-    - 1.04:  removed bogus extra argument from usage fprintf() [Glenn R-P?];
-              fixed command-line parsing bug
-    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
-    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
-    - 1.21:  made minor tweak to usage screen to fit within 25-line console
-    - 1.22:  added AMD64/EM64T support (__x86_64__)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed 64-bit typo in readpng2.c
-    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
-              unexpected-EOF and file-read-error cases
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng2-win"
-#define LONGNAME  "Progressive PNG Viewer for Windows"
-#define VERSION   "2.02 of 16 March 2008"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <setjmp.h>    /* for jmpbuf declaration in readpng2.h */
-#include <time.h>
-#include <math.h>      /* only for PvdM background code */
-#include <windows.h>
-#include <conio.h>     /* only for _getch() */
-
-/* all for PvdM background code: */
-#ifndef PI
-#  define PI             3.141592653589793238
-#endif
-#define PI_2             (PI*0.5)
-#define INV_PI_360       (360.0 / PI)
-#define MAX(a,b)         (a>b?a:b)
-#define MIN(a,b)         (a<b?a:b)
-#define CLIP(a,min,max)  MAX(min,MIN((a),max))
-#define ABS(a)           ((a)<0?-(a):(a))
-#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
-#define ROUNDF(f)        ((int)(f + 0.5))
-
-#define rgb1_max   bg_freq
-#define rgb1_min   bg_gray
-#define rgb2_max   bg_bsat
-#define rgb2_min   bg_brot
-
-/* #define DEBUG */     /* this enables the Trace() macros */
-
-#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
-                          *  block size corresponds roughly to a download
-                          *  speed 10% faster than theoretical 33.6K maximum
-                          *  (assuming 8 data bits, 1 stop bit and no other
-                          *  overhead) */
-
-/* local prototypes */
-static void       rpng2_win_init(void);
-static int        rpng2_win_create_window(void);
-static int        rpng2_win_load_bg_image(void);
-static void       rpng2_win_display_row(ulg row);
-static void       rpng2_win_finish_display(void);
-static void       rpng2_win_cleanup(void);
-LRESULT CALLBACK  rpng2_win_wndproc(HWND, UINT, WPARAM, LPARAM);
-
-
-static char titlebar[1024];
-static char *progname = PROGNAME;
-static char *appname = LONGNAME;
-static char *filename;
-static FILE *infile;
-
-static mainprog_info rpng2_info;
-
-static uch inbuf[INBUFSIZE];
-static int incount;
-
-static int pat = 6;         /* must be less than num_bgpat */
-static int bg_image = 0;
-static int bgscale = 16;
-static ulg bg_rowbytes;
-static uch *bg_data;
-
-static struct rgb_color {
-    uch r, g, b;
-} rgb[] = {
-    {  0,   0,   0},    /*  0:  black */
-    {255, 255, 255},    /*  1:  white */
-    {173, 132,  57},    /*  2:  tan */
-    { 64, 132,   0},    /*  3:  medium green */
-    {189, 117,   1},    /*  4:  gold */
-    {253, 249,   1},    /*  5:  yellow */
-    {  0,   0, 255},    /*  6:  blue */
-    {  0,   0, 120},    /*  7:  medium blue */
-    {255,   0, 255},    /*  8:  magenta */
-    { 64,   0,  64},    /*  9:  dark magenta */
-    {255,   0,   0},    /* 10:  red */
-    { 64,   0,   0},    /* 11:  dark red */
-    {255, 127,   0},    /* 12:  orange */
-    {192,  96,   0},    /* 13:  darker orange */
-    { 24,  60,   0},    /* 14:  dark green-yellow */
-    { 85, 125, 200}     /* 15:  ice blue */
-};
-/* not used for now, but should be for error-checking:
-static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
- */
-
-/*
-    This whole struct is a fairly cheesy way to keep the number of
-    command-line options to a minimum.  The radial-waves background
-    type is a particularly poor fit to the integer elements of the
-    struct...but a few macros and a little fixed-point math will do
-    wonders for ya.
-
-    type bits:
-       F E D C B A 9 8 7 6 5 4 3 2 1 0
-                             | | | | |
-                             | | +-+-+-- 0 = sharp-edged checkerboard
-                             | |         1 = soft diamonds
-                             | |         2 = radial waves
-                             | |       3-7 = undefined
-                             | +-- gradient #2 inverted?
-                             +-- alternating columns inverted?
- */
-static struct background_pattern {
-    ush type;
-    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
-    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
-} bg[] = {
-    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
-    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
-    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
-    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
-    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
-    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
-    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
-    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
-    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
-    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
-    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
-    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
-    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
-    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
-    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
-    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
-};
-static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
-
-
-/* Windows-specific global variables (could go in struct, but messy...) */
-static ulg wimage_rowbytes;
-static uch *dib;
-static uch *wimage_data;
-static BITMAPINFOHEADER *bmih;
-
-static HWND global_hwnd;
-static HINSTANCE global_hInst;
-static int global_showmode;
-
-
-
-
-int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
-{
-    char *args[1024];                 /* arbitrary limit, but should suffice */
-    char **argv = args;
-    char *p, *q, *bgstr = NULL;
-    int argc = 0;
-    int rc, alen, flen;
-    int error = 0;
-    int timing = FALSE;
-    int have_bg = FALSE;
-    double LUT_exponent;              /* just the lookup table */
-    double CRT_exponent = 2.2;        /* just the monitor */
-    double default_display_exponent;  /* whole display system */
-    MSG msg;
-
-
-    /* First initialize a few things, just to be sure--memset takes care of
-     * default background color (black), booleans (FALSE), pointers (NULL),
-     * etc. */
-
-    global_hInst = hInst;
-    global_showmode = showmode;
-    filename = (char *)NULL;
-    memset(&rpng2_info, 0, sizeof(mainprog_info));
-
-
-    /* Next reenable console output, which normally goes to the bit bucket
-     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
-     * incantation. */
-
-    AllocConsole();
-    freopen("CONOUT$", "a", stderr);
-    freopen("CONOUT$", "a", stdout);
-
-
-    /* Set the default value for our display-system exponent, i.e., the
-     * product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities.  And
-     * yes, these ifdefs are completely wasted in a Windows program... */
-
-#if defined(NeXT)
-    /* third-party utilities can modify the default LUT exponent */
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to
-     * get the "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        rpng2_info.display_exponent = atof(p);
-    else
-        rpng2_info.display_exponent = default_display_exponent;
-
-
-    /* Windows really hates command lines, so we have to set up our own argv.
-     * Note that we do NOT bother with quoted arguments here, so don't use
-     * filenames with spaces in 'em! */
-
-    argv[argc++] = PROGNAME;
-    p = cmd;
-    for (;;) {
-        if (*p == ' ')
-            while (*++p == ' ')
-                ;
-        /* now p points at the first non-space after some spaces */
-        if (*p == '\0')
-            break;    /* nothing after the spaces:  done */
-        argv[argc++] = q = p;
-        while (*q && *q != ' ')
-            ++q;
-        /* now q points at a space or the end of the string */
-        if (*q == '\0')
-            break;    /* last argv already terminated; quit */
-        *q = '\0';    /* change space to terminator */
-        p = q + 1;
-    }
-    argv[argc] = NULL;   /* terminate the argv array itself */
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                rpng2_info.display_exponent = atof(*argv);
-                if (rpng2_info.display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else {
-                    have_bg = TRUE;
-                    bg_image = FALSE;
-                }
-            }
-        } else if (!strncmp(*argv, "-bgpat", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                pat = atoi(*argv) - 1;
-                if (pat < 0 || pat >= num_bgpat)
-                    ++error;
-                else {
-                    bg_image = TRUE;
-                    have_bg = FALSE;
-                }
-            }
-        } else if (!strncmp(*argv, "-timing", 2)) {
-            timing = TRUE;
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-        } else if (!strncmp(*argv, "-nommxfilters", 7)) {
-            rpng2_info.nommxfilters = TRUE;
-        } else if (!strncmp(*argv, "-nommxcombine", 7)) {
-            rpng2_info.nommxcombine = TRUE;
-        } else if (!strncmp(*argv, "-nommxinterlace", 7)) {
-            rpng2_info.nommxinterlace = TRUE;
-        } else if (!strcmp(*argv, "-nommx")) {
-            rpng2_info.nommxfilters = TRUE;
-            rpng2_info.nommxcombine = TRUE;
-            rpng2_info.nommxinterlace = TRUE;
-#endif
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-        int ch;
-
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng2_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-gamma exp] [-bgcolor bg | -bgpat pat] [-timing]\n"
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-          "        %*s [[-nommxfilters] [-nommxcombine] [-nommxinterlace] | -nommx]\n"
-#endif
-          "        %*s file.png\n\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images; overrides -bgpat option\n"
-          "    pat \tdesired background pattern number (1-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor option\n"
-          "    -timing\tenables delay for every block read, to simulate modem\n"
-          "\t\t  download of image (~36 Kbps)\n"
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-          "    -nommx*\tdisable optimized MMX routines for decoding row filters,\n"
-          "\t\t  combining rows, and expanding interlacing, respectively\n"
-#endif
-          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
-          "Press Q or Esc to quit this usage screen. ",
-          PROGNAME,
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-          (int)strlen(PROGNAME), " ",
-#endif
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat);
-        fflush(stderr);
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
-            fprintf(stderr, PROGNAME
-              ":  [%s] is not a PNG file: incorrect signature\n",
-              filename);
-            ++error;
-        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
-            switch (rc) {
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng2_init() error\n");
-                    break;
-            }
-            ++error;
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-        int ch;
-
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-        exit(2);
-    } else {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-        fprintf(stderr,
-          "\n   [console window:  closing this window will terminate %s]\n\n",
-          PROGNAME);
-        fflush(stderr);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* set some final rpng2_info variables before entering main data loop */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        rpng2_info.bg_red   = (uch)r;
-        rpng2_info.bg_green = (uch)g;
-        rpng2_info.bg_blue  = (uch)b;
-    } else
-        rpng2_info.need_bgcolor = TRUE;
-
-    rpng2_info.state = kPreInit;
-    rpng2_info.mainprog_init = rpng2_win_init;
-    rpng2_info.mainprog_display_row = rpng2_win_display_row;
-    rpng2_info.mainprog_finish_display = rpng2_win_finish_display;
-
-
-    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
-     * the loop to deal with our first buffer of data (read in above to verify
-     * that the file is a PNG image), then loop through the file and continue
-     * calling the same routine to handle each chunk of data.  It in turn
-     * passes the data to libpng, which will invoke one or more of our call-
-     * backs as decoded data become available.  We optionally call Sleep() for
-     * one second per iteration to simulate downloading the image via an analog
-     * modem. */
-
-    for (;;) {
-        Trace((stderr, "about to call readpng2_decode_data()\n"))
-        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
-            ++error;
-        Trace((stderr, "done with readpng2_decode_data()\n"))
-
-        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
-            if (rpng2_info.state == kDone) {
-                Trace((stderr, "done decoding PNG image\n"))
-            } else if (ferror(infile)) {
-                fprintf(stderr, PROGNAME
-                  ":  error while reading PNG image file\n");
-                exit(3);
-            } else if (feof(infile)) {
-                fprintf(stderr, PROGNAME ":  end of file reached "
-                  "(unexpectedly) while reading PNG image file\n");
-                exit(3);
-            } else /* if (error) */ {
-                // will print error message below
-            }
-            break;
-        }
-
-        if (timing)
-            Sleep(1000L);
-
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-    }
-
-
-    /* clean up PNG stuff and report any decoding errors */
-
-    fclose(infile);
-    Trace((stderr, "about to call readpng2_cleanup()\n"))
-    readpng2_cleanup(&rpng2_info);
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
-        exit(3);
-    }
-
-
-    /* wait for the user to tell us when to quit */
-
-    while (GetMessage(&msg, NULL, 0, 0)) {
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-    }
-
-
-    /* we're done:  clean up all image and Windows resources and go away */
-
-    Trace((stderr, "about to call rpng2_win_cleanup()\n"))
-    rpng2_win_cleanup();
-
-    return msg.wParam;
-}
-
-
-
-
-
-/* this function is called by readpng2_info_callback() in readpng2.c, which
- * in turn is called by libpng after all of the pre-IDAT chunks have been
- * read and processed--i.e., we now have enough info to finish initializing */
-
-static void rpng2_win_init()
-{
-    ulg i;
-    ulg rowbytes = rpng2_info.rowbytes;
-
-    Trace((stderr, "beginning rpng2_win_init()\n"))
-    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
-    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
-    Trace((stderr, "  height = %ld\n", rpng2_info.height))
-
-    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
-    if (!rpng2_info.image_data) {
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
-    if (!rpng2_info.row_pointers) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    for (i = 0;  i < rpng2_info.height;  ++i)
-        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
-
-/*---------------------------------------------------------------------------
-    Do the basic Windows initialization stuff, make the window, and fill it
-    with the user-specified, file-specified or default background color.
-  ---------------------------------------------------------------------------*/
-
-    if (rpng2_win_create_window()) {
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    rpng2_info.state = kWindowInit;
-}
-
-
-
-
-
-static int rpng2_win_create_window()
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *dest;
-    int extra_width, extra_height;
-    ulg i, j;
-    WNDCLASSEX wndclass;
-    RECT rect;
-
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the display-specific version of the image (round up
-    to multiple of 4 for Windows DIB).
-  ---------------------------------------------------------------------------*/
-
-    wimage_rowbytes = ((3*rpng2_info.width + 3L) >> 2) << 2;
-
-    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
-                              wimage_rowbytes*rpng2_info.height)))
-    {
-        return 4;   /* fail */
-    }
-
-/*---------------------------------------------------------------------------
-    Initialize the DIB.  Negative height means to use top-down BMP ordering
-    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
-    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
-    directly => wimage_data begins immediately after BMP header.
-  ---------------------------------------------------------------------------*/
-
-    memset(dib, 0, sizeof(BITMAPINFOHEADER));
-    bmih = (BITMAPINFOHEADER *)dib;
-    bmih->biSize = sizeof(BITMAPINFOHEADER);
-    bmih->biWidth = rpng2_info.width;
-    bmih->biHeight = -((long)rpng2_info.height);
-    bmih->biPlanes = 1;
-    bmih->biBitCount = 24;
-    bmih->biCompression = 0;
-    wimage_data = dib + sizeof(BITMAPINFOHEADER);
-
-/*---------------------------------------------------------------------------
-    Fill window with the specified background color (default is black), but
-    defer loading faked "background image" until window is displayed (may be
-    slow to compute).  Data are in BGR order.
-  ---------------------------------------------------------------------------*/
-
-    if (bg_image) {   /* just fill with black for now */
-        memset(wimage_data, 0, wimage_rowbytes*rpng2_info.height);
-    } else {
-        for (j = 0;  j < rpng2_info.height;  ++j) {
-            dest = wimage_data + j*wimage_rowbytes;
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                *dest++ = bg_blue;
-                *dest++ = bg_green;
-                *dest++ = bg_red;
-            }
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Set the window parameters.
-  ---------------------------------------------------------------------------*/
-
-    memset(&wndclass, 0, sizeof(wndclass));
-
-    wndclass.cbSize = sizeof(wndclass);
-    wndclass.style = CS_HREDRAW | CS_VREDRAW;
-    wndclass.lpfnWndProc = rpng2_win_wndproc;
-    wndclass.hInstance = global_hInst;
-    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
-    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
-    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
-    wndclass.lpszMenuName = NULL;
-    wndclass.lpszClassName = progname;
-    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
-
-    RegisterClassEx(&wndclass);
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
-                      GetSystemMetrics(SM_CXDLGFRAME));
-    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
-                      GetSystemMetrics(SM_CYDLGFRAME)) +
-                      GetSystemMetrics(SM_CYCAPTION);
-
-    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
-      CW_USEDEFAULT, CW_USEDEFAULT, rpng2_info.width+extra_width,
-      rpng2_info.height+extra_height, NULL, NULL, global_hInst, NULL);
-
-    ShowWindow(global_hwnd, global_showmode);
-    UpdateWindow(global_hwnd);
-
-/*---------------------------------------------------------------------------
-    Now compute the background image and display it.  If it fails (memory
-    allocation), revert to a plain background color.
-  ---------------------------------------------------------------------------*/
-
-    if (bg_image) {
-        static const char *msg = "Computing background image...";
-        int x, y, len = strlen(msg);
-        HDC hdc = GetDC(global_hwnd);
-        TEXTMETRIC tm;
-
-        GetTextMetrics(hdc, &tm);
-        x = (rpng2_info.width - len*tm.tmAveCharWidth)/2;
-        y = (rpng2_info.height - tm.tmHeight)/2;
-        SetBkMode(hdc, TRANSPARENT);
-        SetTextColor(hdc, GetSysColor(COLOR_HIGHLIGHTTEXT));
-        /* this can still begin out of bounds even if x is positive (???): */
-        TextOut(hdc, ((x < 0)? 0 : x), ((y < 0)? 0 : y), msg, len);
-        ReleaseDC(global_hwnd, hdc);
-
-        rpng2_win_load_bg_image();   /* resets bg_image if fails */
-    }
-
-    if (!bg_image) {
-        for (j = 0;  j < rpng2_info.height;  ++j) {
-            dest = wimage_data + j*wimage_rowbytes;
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                *dest++ = bg_blue;
-                *dest++ = bg_green;
-                *dest++ = bg_red;
-            }
-        }
-    }
-
-    rect.left = 0L;
-    rect.top = 0L;
-    rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
-    rect.bottom = (LONG)rpng2_info.height;     /* possibly off by one? */
-    InvalidateRect(global_hwnd, &rect, FALSE);
-    UpdateWindow(global_hwnd);                 /* similar to XFlush() */
-
-    return 0;
-
-} /* end function rpng2_win_create_window() */
-
-
-
-
-
-static int rpng2_win_load_bg_image()
-{
-    uch *src, *dest;
-    uch r1, r2, g1, g2, b1, b2;
-    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
-    int k, hmax, max;
-    int xidx, yidx, yidx_max = (bgscale-1);
-    int even_odd_vert, even_odd_horiz, even_odd;
-    int invert_gradient2 = (bg[pat].type & 0x08);
-    int invert_column;
-    ulg i, row;
-
-/*---------------------------------------------------------------------------
-    Allocate buffer for fake background image to be used with transparent
-    images; if this fails, revert to plain background color.
-  ---------------------------------------------------------------------------*/
-
-    bg_rowbytes = 3 * rpng2_info.width;
-    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
-    if (!bg_data) {
-        fprintf(stderr, PROGNAME
-          ":  unable to allocate memory for background image\n");
-        bg_image = 0;
-        return 1;
-    }
-
-/*---------------------------------------------------------------------------
-    Vertical gradients (ramps) in NxN squares, alternating direction and
-    colors (N == bgscale).
-  ---------------------------------------------------------------------------*/
-
-    if ((bg[pat].type & 0x07) == 0) {
-        uch r1_min  = rgb[bg[pat].rgb1_min].r;
-        uch g1_min  = rgb[bg[pat].rgb1_min].g;
-        uch b1_min  = rgb[bg[pat].rgb1_min].b;
-        uch r2_min  = rgb[bg[pat].rgb2_min].r;
-        uch g2_min  = rgb[bg[pat].rgb2_min].g;
-        uch b2_min  = rgb[bg[pat].rgb2_min].b;
-        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
-        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
-        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
-        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
-        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
-        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = row % bgscale;
-            even_odd_vert = (row / bgscale) & 1;
-
-            r1 = r1_min + (r1_diff * yidx) / yidx_max;
-            g1 = g1_min + (g1_diff * yidx) / yidx_max;
-            b1 = b1_min + (b1_diff * yidx) / yidx_max;
-            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
-            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
-            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
-
-            r2 = r2_min + (r2_diff * yidx) / yidx_max;
-            g2 = g2_min + (g2_diff * yidx) / yidx_max;
-            b2 = b2_min + (b2_diff * yidx) / yidx_max;
-            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
-            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
-            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
-
-            dest = bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                even_odd_horiz = (i / bgscale) & 1;
-                even_odd = even_odd_vert ^ even_odd_horiz;
-                invert_column =
-                  (even_odd_horiz && (bg[pat].type & 0x10));
-                if (even_odd == 0) {         /* gradient #1 */
-                    if (invert_column) {
-                        *dest++ = r1_inv;
-                        *dest++ = g1_inv;
-                        *dest++ = b1_inv;
-                    } else {
-                        *dest++ = r1;
-                        *dest++ = g1;
-                        *dest++ = b1;
-                    }
-                } else {                     /* gradient #2 */
-                    if ((invert_column && invert_gradient2) ||
-                        (!invert_column && !invert_gradient2))
-                    {
-                        *dest++ = r2;        /* not inverted or */
-                        *dest++ = g2;        /*  doubly inverted */
-                        *dest++ = b2;
-                    } else {
-                        *dest++ = r2_inv;
-                        *dest++ = g2_inv;    /* singly inverted */
-                        *dest++ = b2_inv;
-                    }
-                }
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
-    M. Costello.
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 1) {
-
-        hmax = (bgscale-1)/2;   /* half the max weight of a color */
-        max = 2*hmax;           /* the max weight of a color */
-
-        r1 = rgb[bg[pat].rgb1_max].r;
-        g1 = rgb[bg[pat].rgb1_max].g;
-        b1 = rgb[bg[pat].rgb1_max].b;
-        r2 = rgb[bg[pat].rgb2_max].r;
-        g2 = rgb[bg[pat].rgb2_max].g;
-        b2 = rgb[bg[pat].rgb2_max].b;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = row % bgscale;
-            if (yidx > hmax)
-                yidx = bgscale-1 - yidx;
-            dest = bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                xidx = i % bgscale;
-                if (xidx > hmax)
-                    xidx = bgscale-1 - xidx;
-                k = xidx + yidx;
-                *dest++ = (k*r1 + (max-k)*r2) / max;
-                *dest++ = (k*g1 + (max-k)*g2) / max;
-                *dest++ = (k*b1 + (max-k)*b2) / max;
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
-    soids will equal bgscale?].  This one is slow but very cool.  Code con-
-    tributed by Pieter S. van der Meulen (originally in Smalltalk).
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 2) {
-        uch ch;
-        int ii, x, y, hw, hh, grayspot;
-        double freq, rotate, saturate, gray, intensity;
-        double angle=0.0, aoffset=0.0, maxDist, dist;
-        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
-
-        fprintf(stderr, "%s:  computing radial background...",
-          PROGNAME);
-        fflush(stderr);
-
-        hh = rpng2_info.height / 2;
-        hw = rpng2_info.width / 2;
-
-        /* variables for radial waves:
-         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
-         *   freq:  number of color beams originating from the center
-         *   grayspot:  size of the graying center area (anti-alias)
-         *   rotate:  rotation of the beams as a function of radius
-         *   saturate:  saturation of beams' shape azimuthally
-         */
-        angle = CLIP(angle, 0.0, 360.0);
-        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
-        freq = MAX((double)bg[pat].bg_freq, 0.0);
-        saturate = (double)bg[pat].bg_bsat * 0.1;
-        rotate = (double)bg[pat].bg_brot * 0.1;
-        gray = 0.0;
-        intensity = 0.0;
-        maxDist = (double)((hw*hw) + (hh*hh));
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            y = row - hh;
-            dest = bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                x = i - hw;
-                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
-                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
-                gray = MIN(1.0, gray);
-                dist = (double)((x*x) + (y*y)) / maxDist;
-                intensity = cos((angle+(rotate*dist*PI)) * freq) *
-                  gray * saturate;
-                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
-                hue = (angle + PI) * INV_PI_360 + aoffset;
-                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
-                s = MIN(MAX(s,0.0), 1.0);
-                v = MIN(MAX(intensity,0.0), 1.0);
-
-                if (s == 0.0) {
-                    ch = (uch)(v * 255.0);
-                    *dest++ = ch;
-                    *dest++ = ch;
-                    *dest++ = ch;
-                } else {
-                    if ((hue < 0.0) || (hue >= 360.0))
-                        hue -= (((int)(hue / 360.0)) * 360.0);
-                    hue /= 60.0;
-                    ii = (int)hue;
-                    f = hue - (double)ii;
-                    p = (1.0 - s) * v;
-                    q = (1.0 - (s * f)) * v;
-                    t = (1.0 - (s * (1.0 - f))) * v;
-                    if      (ii == 0) { red = v; green = t; blue = p; }
-                    else if (ii == 1) { red = q; green = v; blue = p; }
-                    else if (ii == 2) { red = p; green = v; blue = t; }
-                    else if (ii == 3) { red = p; green = q; blue = v; }
-                    else if (ii == 4) { red = t; green = p; blue = v; }
-                    else if (ii == 5) { red = v; green = p; blue = q; }
-                    *dest++ = (uch)(red * 255.0);
-                    *dest++ = (uch)(green * 255.0);
-                    *dest++ = (uch)(blue * 255.0);
-                }
-            }
-        }
-        fprintf(stderr, "done.\n");
-        fflush(stderr);
-    }
-
-/*---------------------------------------------------------------------------
-    Blast background image to display buffer before beginning PNG decode;
-    calling function will handle invalidation and UpdateWindow() call.
-  ---------------------------------------------------------------------------*/
-
-    for (row = 0;  row < rpng2_info.height;  ++row) {
-        src = bg_data + row*bg_rowbytes;
-        dest = wimage_data + row*wimage_rowbytes;
-        for (i = rpng2_info.width;  i > 0;  --i) {
-            r1 = *src++;
-            g1 = *src++;
-            b1 = *src++;
-            *dest++ = b1;
-            *dest++ = g1;   /* note reverse order */
-            *dest++ = r1;
-        }
-    }
-
-    return 0;
-
-} /* end function rpng2_win_load_bg_image() */
-
-
-
-
-
-static void rpng2_win_display_row(ulg row)
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *src, *src2=NULL, *dest;
-    uch r, g, b, a;
-    ulg i;
-    static int rows=0;
-    static ulg firstrow;
-
-/*---------------------------------------------------------------------------
-    rows and firstrow simply track how many rows (and which ones) have not
-    yet been displayed; alternatively, we could call InvalidateRect() for
-    every row and not bother with the records-keeping.
-  ---------------------------------------------------------------------------*/
-
-    Trace((stderr, "beginning rpng2_win_display_row()\n"))
-
-    if (rows == 0)
-        firstrow = row;   /* first row not yet displayed */
-
-    ++rows;   /* count of rows received but not yet displayed */
-
-/*---------------------------------------------------------------------------
-    Aside from the use of the rpng2_info struct and the lack of an outer
-    loop (over rows), this routine is identical to rpng_win_display_image()
-    in the non-progressive version of the program.
-  ---------------------------------------------------------------------------*/
-
-    src = rpng2_info.image_data + row*rpng2_info.rowbytes;
-    if (bg_image)
-        src2 = bg_data + row*bg_rowbytes;
-    dest = wimage_data + row*wimage_rowbytes;
-
-    if (rpng2_info.channels == 3) {
-        for (i = rpng2_info.width;  i > 0;  --i) {
-            r = *src++;
-            g = *src++;
-            b = *src++;
-            *dest++ = b;
-            *dest++ = g;   /* note reverse order */
-            *dest++ = r;
-        }
-    } else /* if (rpng2_info.channels == 4) */ {
-        for (i = rpng2_info.width;  i > 0;  --i) {
-            r = *src++;
-            g = *src++;
-            b = *src++;
-            a = *src++;
-            if (bg_image) {
-                bg_red   = *src2++;
-                bg_green = *src2++;
-                bg_blue  = *src2++;
-            }
-            if (a == 255) {
-                *dest++ = b;
-                *dest++ = g;
-                *dest++ = r;
-            } else if (a == 0) {
-                *dest++ = bg_blue;
-                *dest++ = bg_green;
-                *dest++ = bg_red;
-            } else {
-                /* this macro (copied from png.h) composites the
-                 * foreground and background values and puts the
-                 * result into the first argument; there are no
-                 * side effects with the first argument */
-                alpha_composite(*dest++, b, a, bg_blue);
-                alpha_composite(*dest++, g, a, bg_green);
-                alpha_composite(*dest++, r, a, bg_red);
-            }
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Display after every 16 rows or when on last row.  (Region may include
-    previously displayed lines due to interlacing--i.e., not contiguous.)
-  ---------------------------------------------------------------------------*/
-
-    if ((rows & 0xf) == 0 || row == rpng2_info.height-1) {
-        RECT rect;
-
-        rect.left = 0L;
-        rect.top = (LONG)firstrow;
-        rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
-        rect.bottom = (LONG)row + 1L;              /* possibly off by one? */
-        InvalidateRect(global_hwnd, &rect, FALSE);
-        UpdateWindow(global_hwnd);                 /* similar to XFlush() */
-        rows = 0;
-    }
-
-} /* end function rpng2_win_display_row() */
-
-
-
-
-
-static void rpng2_win_finish_display()
-{
-    Trace((stderr, "beginning rpng2_win_finish_display()\n"))
-
-    /* last row has already been displayed by rpng2_win_display_row(), so
-     * we have nothing to do here except set a flag and let the user know
-     * that the image is done */
-
-    rpng2_info.state = kDone;
-    printf(
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
-    fflush(stdout);
-}
-
-
-
-
-
-static void rpng2_win_cleanup()
-{
-    if (bg_image && bg_data) {
-        free(bg_data);
-        bg_data = NULL;
-    }
-
-    if (rpng2_info.image_data) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-    }
-
-    if (rpng2_info.row_pointers) {
-        free(rpng2_info.row_pointers);
-        rpng2_info.row_pointers = NULL;
-    }
-
-    if (dib) {
-        free(dib);
-        dib = NULL;
-    }
-}
-
-
-
-
-
-LRESULT CALLBACK rpng2_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
-{
-    HDC         hdc;
-    PAINTSTRUCT ps;
-    int rc;
-
-    switch (iMsg) {
-        case WM_CREATE:
-            /* one-time processing here, if any */
-            return 0;
-
-        case WM_PAINT:
-            hdc = BeginPaint(hwnd, &ps);
-            rc = StretchDIBits(hdc, 0, 0, rpng2_info.width, rpng2_info.height,
-                                    0, 0, rpng2_info.width, rpng2_info.height,
-                                    wimage_data, (BITMAPINFO *)bmih,
-                                    0, SRCCOPY);
-            EndPaint(hwnd, &ps);
-            return 0;
-
-        /* wait for the user to tell us when to quit */
-        case WM_CHAR:
-            switch (wP) {       /* only need one, so ignore repeat count */
-                case 'q':
-                case 'Q':
-                case 0x1B:      /* Esc key */
-                    PostQuitMessage(0);
-            }
-            return 0;
-
-        case WM_LBUTTONDOWN:    /* another way of quitting */
-        case WM_DESTROY:
-            PostQuitMessage(0);
-            return 0;
-    }
-
-    return DefWindowProc(hwnd, iMsg, wP, lP);
-}
diff --git a/contrib/gregbook/rpng2-x.c b/contrib/gregbook/rpng2-x.c
deleted file mode 100644
index 873af23..0000000
--- a/contrib/gregbook/rpng2-x.c
+++ /dev/null
@@ -1,2127 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                  rpng2-x.c
-
-   This program decodes and displays PNG files progressively, as if it were
-   a web browser (though the front end is only set up to read from files).
-   It supports gamma correction, user-specified background colors, and user-
-   specified background patterns (for transparent images).  This version is
-   for the X Window System (tested by the author under Unix and by Martin
-   Zinser under OpenVMS; may work under OS/2 with a little tweaking).
-
-   Thanks to Adam Costello and Pieter S. van der Meulen for the "diamond"
-   and "radial waves" patterns, respectively.
-
-   to do (someday, maybe):
-    - fix expose/redraw code:  don't draw entire row if only part exposed
-    - 8-bit (colormapped) X support
-    - finish resizable checkerboard-gradient (sizes 4-128?)
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options; fixed char/uchar mismatch
-    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
-    - 1.11:  added -usleep option for demos; fixed command-line parsing bug
-    - 1.12:  added -pause option for demos and testing
-    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
-    - 1.21:  fixed some small X memory leaks (thanks to François Petitjean)
-    - 1.22:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
-    - 1.23:  added -bgpat 0 mode (std white/gray checkerboard, 8x8 squares)
-    - 1.30:  added -loop option for -bgpat (ifdef FEATURE_LOOP); fixed bpp =
-              24; added support for X resources (thanks to Gerhard Niklasch)
-    - 1.31:  added code to skip unused chunks (thanks to Glenn Randers-Pehrson)
-    - 1.32:  added AMD64/EM64T support (__x86_64__); added basic expose/redraw
-              handling
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed 64-bit typo in readpng2.c; fixed -pause usage description
-    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
-              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
-              paste bugs
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng2-x"
-#define LONGNAME  "Progressive PNG Viewer for X"
-#define VERSION   "2.02 of 16 March 2008"
-#define RESNAME   "rpng2"	/* our X resource application name */
-#define RESCLASS  "Rpng"	/* our X resource class name */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <ctype.h>
-#include <string.h>
-#include <setjmp.h>       /* for jmpbuf declaration in readpng2.h */
-#include <time.h>
-#include <math.h>         /* only for PvdM background code */
-#include <X11/Xlib.h>
-#include <X11/Xutil.h>
-#include <X11/Xos.h>
-#include <X11/keysym.h>   /* defines XK_* macros */
-
-#ifdef VMS
-#  include <unistd.h>
-#endif
-
-/* all for PvdM background code: */
-#ifndef PI
-#  define PI             3.141592653589793238
-#endif
-#define PI_2             (PI*0.5)
-#define INV_PI_360       (360.0 / PI)
-#define MAX(a,b)         (a>b?a:b)
-#define MIN(a,b)         (a<b?a:b)
-#define CLIP(a,min,max)  MAX(min,MIN((a),max))
-#define ABS(a)           ((a)<0?-(a):(a))
-#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
-#define ROUNDF(f)        ((int)(f + 0.5))
-
-#define QUIT(e,k) ((e.type == ButtonPress && e.xbutton.button == Button1) ||  \
-                  (e.type == KeyPress &&   /*  v--- or 1 for shifted keys */  \
-                  ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape)))
-
-#define NO_24BIT_MASKS	/* undef case not fully written--only for redisplay() */
-
-#define rgb1_max   bg_freq
-#define rgb1_min   bg_gray
-#define rgb2_max   bg_bsat
-#define rgb2_min   bg_brot
-
-/* #define DEBUG */     /* this enables the Trace() macros */
-
-#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
-                          *  block size corresponds roughly to a download
-                          *  speed 10% faster than theoretical 33.6K maximum
-                          *  (assuming 8 data bits, 1 stop bit and no other
-                          *  overhead) */
-
-/* local prototypes */
-static void rpng2_x_init (void);
-static int  rpng2_x_create_window (void);
-static int  rpng2_x_load_bg_image (void);
-static void rpng2_x_display_row (ulg row);
-static void rpng2_x_finish_display (void);
-static void rpng2_x_redisplay_image (ulg startcol, ulg startrow,
-                                     ulg width, ulg height);
-#ifdef FEATURE_LOOP
-static void rpng2_x_reload_bg_image (void);
-static int  is_number (char *p);
-#endif
-static void rpng2_x_cleanup (void);
-static int  rpng2_x_msb (ulg u32val);
-
-
-static char titlebar[1024], *window_name = titlebar;
-static char *appname = LONGNAME;
-static char *icon_name = PROGNAME;
-static char *res_name = RESNAME;
-static char *res_class = RESCLASS;
-static char *filename;
-static FILE *infile;
-
-static mainprog_info rpng2_info;
-
-static uch inbuf[INBUFSIZE];
-static int incount;
-
-static int pat = 6;        /* must be less than num_bgpat */
-static int bg_image = 0;
-static int bgscale, bgscale_default = 16;
-static ulg bg_rowbytes;
-static uch *bg_data;
-
-int pause_after_pass = FALSE;
-int demo_timing = FALSE;
-ulg usleep_duration = 0L;
-
-static struct rgb_color {
-    uch r, g, b;
-} rgb[] = {
-    {  0,   0,   0},    /*  0:  black */
-    {255, 255, 255},    /*  1:  white */
-    {173, 132,  57},    /*  2:  tan */
-    { 64, 132,   0},    /*  3:  medium green */
-    {189, 117,   1},    /*  4:  gold */
-    {253, 249,   1},    /*  5:  yellow */
-    {  0,   0, 255},    /*  6:  blue */
-    {  0,   0, 120},    /*  7:  medium blue */
-    {255,   0, 255},    /*  8:  magenta */
-    { 64,   0,  64},    /*  9:  dark magenta */
-    {255,   0,   0},    /* 10:  red */
-    { 64,   0,   0},    /* 11:  dark red */
-    {255, 127,   0},    /* 12:  orange */
-    {192,  96,   0},    /* 13:  darker orange */
-    { 24,  60,   0},    /* 14:  dark green-yellow */
-    { 85, 125, 200},    /* 15:  ice blue */
-    {192, 192, 192}     /* 16:  Netscape/Mosaic gray */
-};
-/* not used for now, but should be for error-checking:
-static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
- */
-
-/*
-    This whole struct is a fairly cheesy way to keep the number of
-    command-line options to a minimum.  The radial-waves background
-    type is a particularly poor fit to the integer elements of the
-    struct...but a few macros and a little fixed-point math will do
-    wonders for ya.
-
-    type bits:
-       F E D C B A 9 8 7 6 5 4 3 2 1 0
-                             | | | | |
-                             | | +-+-+-- 0 = sharp-edged checkerboard
-                             | |         1 = soft diamonds
-                             | |         2 = radial waves
-                             | |       3-7 = undefined
-                             | +-- gradient #2 inverted?
-                             +-- alternating columns inverted?
- */
-static struct background_pattern {
-    ush type;
-    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
-    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
-} bg[] = {
-    {0,     1,1, 16,16},        /* checkered:  white vs. light gray (basic) */
-    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
-    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
-    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
-    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
-    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
-    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
-    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
-    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
-    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
-    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
-    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
-    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
-    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
-    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
-    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
-    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
-};
-static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
-
-
-/* X-specific variables */
-static char *displayname;
-static XImage *ximage;
-static Display *display;
-static int depth;
-static Visual *visual;
-static XVisualInfo *visual_list;
-static int RShift, GShift, BShift;
-static ulg RMask, GMask, BMask;
-static Window window;
-static GC gc;
-static Colormap colormap;
-
-static int have_nondefault_visual = FALSE;
-static int have_colormap = FALSE;
-static int have_window = FALSE;
-static int have_gc = FALSE;
-
-
-
-
-int main(int argc, char **argv)
-{
-#ifdef sgi
-    char tmpline[80];
-#endif
-    char *p, *bgstr = NULL;
-    int rc, alen, flen;
-    int error = 0;
-    int timing = FALSE;
-    int have_bg = FALSE;
-#ifdef FEATURE_LOOP
-    int loop = FALSE;
-    long loop_interval = -1;		/* seconds (100,000 max) */
-#endif
-    double LUT_exponent;                /* just the lookup table */
-    double CRT_exponent = 2.2;          /* just the monitor */
-    double default_display_exponent;    /* whole display system */
-    XEvent e;
-    KeySym k;
-
-
-    /* First initialize a few things, just to be sure--memset takes care of
-     * default background color (black), booleans (FALSE), pointers (NULL),
-     * etc. */
-
-    displayname = (char *)NULL;
-    filename = (char *)NULL;
-    memset(&rpng2_info, 0, sizeof(mainprog_info));
-
-
-    /* Set the default value for our display-system exponent, i.e., the
-     * product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities. */
-
-#if defined(NeXT)
-    /* third-party utilities can modify the default LUT exponent */
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to
-     * get the "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        rpng2_info.display_exponent = atof(p);
-    else
-        rpng2_info.display_exponent = default_display_exponent;
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-display", 2)) {
-            if (!*++argv)
-                ++error;
-            else
-                displayname = *argv;
-        } else if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                rpng2_info.display_exponent = atof(*argv);
-                if (rpng2_info.display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else {
-                    have_bg = TRUE;
-                    bg_image = FALSE;
-                }
-            }
-        } else if (!strncmp(*argv, "-bgpat", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                pat = atoi(*argv);
-                if (pat >= 0 && pat < num_bgpat) {
-                    bg_image = TRUE;
-                    have_bg = FALSE;
-                } else
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-usleep", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                usleep_duration = (ulg)atol(*argv);
-                demo_timing = TRUE;
-            }
-        } else if (!strncmp(*argv, "-pause", 2)) {
-            pause_after_pass = TRUE;
-        } else if (!strncmp(*argv, "-timing", 2)) {
-            timing = TRUE;
-#ifdef FEATURE_LOOP
-        } else if (!strncmp(*argv, "-loop", 2)) {
-            loop = TRUE;
-            if (!argv[1] || !is_number(argv[1]))
-                loop_interval = 2;
-            else {
-                ++argv;
-                loop_interval = atol(*argv);
-                if (loop_interval < 0)
-                    loop_interval = 2;
-                else if (loop_interval > 100000)   /* bit more than one day */
-                    loop_interval = 100000;
-            }
-#endif
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-        } else if (!strncmp(*argv, "-nommxfilters", 7)) {
-            rpng2_info.nommxfilters = TRUE;
-        } else if (!strncmp(*argv, "-nommxcombine", 7)) {
-            rpng2_info.nommxcombine = TRUE;
-        } else if (!strncmp(*argv, "-nommxinterlace", 7)) {
-            rpng2_info.nommxinterlace = TRUE;
-        } else if (!strcmp(*argv, "-nommx")) {
-            rpng2_info.nommxfilters = TRUE;
-            rpng2_info.nommxcombine = TRUE;
-            rpng2_info.nommxinterlace = TRUE;
-#endif
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng2_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-          "        %*s [[-nommxfilters] [-nommxcombine] [-nommxinterlace] | -nommx]\n"
-#endif
-#ifdef FEATURE_LOOP
-          "        %*s [-usleep dur | -timing] [-pause] [-loop [sec]] file.png\n\n"
-#else
-          "        %*s [-usleep dur | -timing] [-pause] file.png\n\n"
-#endif
-          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images; overrides -bgpat\n"
-          "    pat \tdesired background pattern number (0-%d); used with\n"
-          "\t\t  transparent images; overrides -bgcolor\n"
-#ifdef FEATURE_LOOP
-          "    -loop\tloops through background images after initial display\n"
-          "\t\t  is complete (depends on -bgpat)\n"
-          "    sec \tseconds to display each background image (default = 2)\n"
-#endif
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-          "    -nommx*\tdisable optimized MMX routines for decoding row filters,\n"
-          "\t\t  combining rows, and expanding interlacing, respectively\n"
-#endif
-          "    dur \tduration in microseconds to wait after displaying each\n"
-          "\t\t  row (for demo purposes)\n"
-          "    -timing\tenables delay for every block read, to simulate modem\n"
-          "\t\t  download of image (~36 Kbps)\n"
-          "    -pause\tpauses after displaying each pass until mouse clicked\n"
-          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
-          "is displayed) to quit.\n"
-          "\n", PROGNAME,
-#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__))
-          (int)strlen(PROGNAME), " ",
-#endif
-          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat-1);
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
-            fprintf(stderr, PROGNAME
-              ":  [%s] is not a PNG file: incorrect signature\n",
-              filename);
-            ++error;
-        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
-            switch (rc) {
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng2_init() error\n");
-                    break;
-            }
-            ++error;
-        } else {
-            Trace((stderr, "about to call XOpenDisplay()\n"))
-            display = XOpenDisplay(displayname);
-            if (!display) {
-                readpng2_cleanup(&rpng2_info);
-                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
-                  displayname? displayname : "default");
-                ++error;
-            }
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-        exit(2);
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* set some final rpng2_info variables before entering main data loop */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        rpng2_info.bg_red   = (uch)r;
-        rpng2_info.bg_green = (uch)g;
-        rpng2_info.bg_blue  = (uch)b;
-    } else
-        rpng2_info.need_bgcolor = TRUE;
-
-    rpng2_info.state = kPreInit;
-    rpng2_info.mainprog_init = rpng2_x_init;
-    rpng2_info.mainprog_display_row = rpng2_x_display_row;
-    rpng2_info.mainprog_finish_display = rpng2_x_finish_display;
-
-
-    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
-     * the loop to deal with our first buffer of data (read in above to verify
-     * that the file is a PNG image), then loop through the file and continue
-     * calling the same routine to handle each chunk of data.  It in turn
-     * passes the data to libpng, which will invoke one or more of our call-
-     * backs as decoded data become available.  We optionally call sleep() for
-     * one second per iteration to simulate downloading the image via an analog
-     * modem. */
-
-    for (;;) {
-        Trace((stderr, "about to call readpng2_decode_data()\n"))
-        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
-            ++error;
-        Trace((stderr, "done with readpng2_decode_data()\n"))
-
-        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
-            if (rpng2_info.state == kDone) {
-                Trace((stderr, "done decoding PNG image\n"))
-            } else if (ferror(infile)) {
-                fprintf(stderr, PROGNAME
-                  ":  error while reading PNG image file\n");
-                exit(3);
-            } else if (feof(infile)) {
-                fprintf(stderr, PROGNAME ":  end of file reached "
-                  "(unexpectedly) while reading PNG image file\n");
-                exit(3);
-            } else /* if (error) */ {
-                // will print error message below
-            }
-            break;
-        }
-
-        if (timing)
-            sleep(1);
-
-        incount = fread(inbuf, 1, INBUFSIZE, infile);
-    }
-
-
-    /* clean up PNG stuff and report any decoding errors */
-
-    fclose(infile);
-    Trace((stderr, "about to call readpng2_cleanup()\n"))
-    readpng2_cleanup(&rpng2_info);
-
-    if (error) {
-        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
-        exit(3);
-    }
-
-
-#ifdef FEATURE_LOOP
-
-    if (loop && bg_image) {
-        Trace((stderr, "entering -loop loop (FEATURE_LOOP)\n"))
-        for (;;) {
-            int i, use_sleep;
-            struct timeval now, then;
-
-            /* get current time and add loop_interval to get target time */
-            if (gettimeofday(&then, NULL) == 0) {
-                then.tv_sec += loop_interval;
-                use_sleep = FALSE;
-            } else
-                use_sleep = TRUE;
-
-            /* do quick check for a quit event but don't wait for it */
-            /* GRR BUG:  should also check for Expose events and redraw... */
-            if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask, &e))
-                if (QUIT(e,k))
-                    break;
-
-            /* generate next background image */
-            if (++pat >= num_bgpat)
-                pat = 0;
-            rpng2_x_reload_bg_image();
-
-            /* wait for timeout, using whatever means are available */
-            if (use_sleep || gettimeofday(&now, NULL) != 0) {
-                for (i = loop_interval;  i > 0;  --i) {
-                    sleep(1);
-                    /* GRR BUG:  also need to check for Expose (and redraw!) */
-                    if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask,
-                        &e) && QUIT(e,k))
-                        break;
-                }
-            } else {
-                /* Y2038 BUG! */
-                if (now.tv_sec < then.tv_sec ||
-                    (now.tv_sec == then.tv_sec && now.tv_usec < then.tv_usec))
-                {
-                    int quit = FALSE;
-                    long seconds_to_go = then.tv_sec - now.tv_sec;
-                    long usleep_usec;
-
-                    /* basically chew up most of remaining loop-interval with
-                     *  calls to sleep(1) interleaved with checks for quit
-                     *  events, but also recalc time-to-go periodically; when
-                     *  done, clean up any remaining time with usleep() call
-                     *  (could also use SIGALRM, but signals are a pain...) */
-                    while (seconds_to_go-- > 1) {
-                        int seconds_done = 0;
-
-                        for (i = seconds_to_go;  i > 0 && !quit;  --i) {
-                            sleep(1);
-                            /* GRR BUG:  need to check for Expose and redraw */
-                            if (XCheckMaskEvent(display, KeyPressMask |
-                                ButtonPressMask, &e) && QUIT(e,k))
-                                quit = TRUE;
-                            if (++seconds_done > 1000)
-                                break;   /* time to redo seconds_to_go meas. */
-                        }
-                        if (quit)
-                            break;
-
-                        /* OK, more than 1000 seconds since last check:
-                         *  correct the time-to-go measurement for drift */
-                        if (gettimeofday(&now, NULL) == 0) {
-                            if (now.tv_sec >= then.tv_sec)
-                                break;
-                            seconds_to_go = then.tv_sec - now.tv_sec;
-                        } else
-                            ++seconds_to_go;  /* restore what we subtracted */
-                    }
-                    if (quit)
-                        break;   /* breaks outer do-loop, skips redisplay */
-
-                    /* since difference between "now" and "then" is already
-                     *  eaten up to within a couple of seconds, don't need to
-                     *  worry about overflow--but might have overshot (neg.) */
-                    if (gettimeofday(&now, NULL) == 0) {
-                        usleep_usec = 1000000L*(then.tv_sec - now.tv_sec) +
-                          then.tv_usec - now.tv_usec;
-                        if (usleep_usec > 0)
-                            usleep((ulg)usleep_usec);
-                    }
-                }
-            }
-
-            /* composite image against new background and display (note that
-             *  we do not take into account the time spent doing this...) */
-            rpng2_x_redisplay_image (0, 0, rpng2_info.width, rpng2_info.height);
-        }
-
-    } else /* FALL THROUGH and do the normal thing */
-
-#endif /* FEATURE_LOOP */
-
-    /* wait for the user to tell us when to quit */
-
-    if (rpng2_info.state >= kWindowInit) {
-        Trace((stderr, "entering final wait-for-quit-event loop\n"))
-        do {
-            XNextEvent(display, &e);
-            if (e.type == Expose) {
-                XExposeEvent *ex = (XExposeEvent *)&e;
-                rpng2_x_redisplay_image (ex->x, ex->y, ex->width, ex->height);
-            }
-        } while (!QUIT(e,k));
-    } else {
-        fprintf(stderr, PROGNAME ":  init callback never called:  probable "
-          "libpng error while decoding PNG metadata\n");
-        exit(4);
-    }
-
-
-    /* we're done:  clean up all image and X resources and go away */
-
-    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
-    rpng2_x_cleanup();
-
-    return 0;
-}
-
-
-
-
-
-/* this function is called by readpng2_info_callback() in readpng2.c, which
- * in turn is called by libpng after all of the pre-IDAT chunks have been
- * read and processed--i.e., we now have enough info to finish initializing */
-
-static void rpng2_x_init(void)
-{
-    ulg i;
-    ulg rowbytes = rpng2_info.rowbytes;
-
-    Trace((stderr, "beginning rpng2_x_init()\n"))
-    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
-    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
-    Trace((stderr, "  height = %ld\n", rpng2_info.height))
-
-    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
-    if (!rpng2_info.image_data) {
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
-    if (!rpng2_info.row_pointers) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-        readpng2_cleanup(&rpng2_info);
-        return;
-    }
-
-    for (i = 0;  i < rpng2_info.height;  ++i)
-        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
-
-
-    /* do the basic X initialization stuff, make the window, and fill it with
-     * the user-specified, file-specified or default background color or
-     * pattern */
-
-    if (rpng2_x_create_window()) {
-
-        /* GRR TEMPORARY HACK:  this is fundamentally no different from cases
-         * above; libpng should longjmp() back to us when png_ptr goes away.
-         * If we/it segfault instead, seems like a libpng bug... */
-
-        /* we're here via libpng callback, so if window fails, clean and bail */
-        readpng2_cleanup(&rpng2_info);
-        rpng2_x_cleanup();
-        exit(2);
-    }
-
-    rpng2_info.state = kWindowInit;
-}
-
-
-
-
-
-static int rpng2_x_create_window(void)
-{
-    ulg bg_red   = rpng2_info.bg_red;
-    ulg bg_green = rpng2_info.bg_green;
-    ulg bg_blue  = rpng2_info.bg_blue;
-    ulg bg_pixel = 0L;
-    ulg attrmask;
-    int need_colormap = FALSE;
-    int screen, pad;
-    uch *xdata;
-    Window root;
-    XEvent e;
-    XGCValues gcvalues;
-    XSetWindowAttributes attr;
-    XTextProperty windowName, *pWindowName = &windowName;
-    XTextProperty iconName, *pIconName = &iconName;
-    XVisualInfo visual_info;
-    XSizeHints *size_hints;
-    XWMHints *wm_hints;
-    XClassHint *class_hints;
-
-
-    Trace((stderr, "beginning rpng2_x_create_window()\n"))
-
-    screen = DefaultScreen(display);
-    depth = DisplayPlanes(display, screen);
-    root = RootWindow(display, screen);
-
-#ifdef DEBUG
-    XSynchronize(display, True);
-#endif
-
-    if (depth != 16 && depth != 24 && depth != 32) {
-        int visuals_matched = 0;
-
-        Trace((stderr, "default depth is %d:  checking other visuals\n",
-          depth))
-
-        /* 24-bit first */
-        visual_info.screen = screen;
-        visual_info.depth = 24;
-        visual_list = XGetVisualInfo(display,
-          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
-        if (visuals_matched == 0) {
-/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
-            fprintf(stderr, "default screen depth %d not supported, and no"
-              " 24-bit visuals found\n", depth);
-            return 2;
-        }
-        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
-          visuals_matched))
-        visual = visual_list[0].visual;
-        depth = visual_list[0].depth;
-/*
-        colormap_size = visual_list[0].colormap_size;
-        visual_class = visual->class;
-        visualID = XVisualIDFromVisual(visual);
- */
-        have_nondefault_visual = TRUE;
-        need_colormap = TRUE;
-    } else {
-        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
-        visual = visual_info.visual;
-    }
-
-    RMask = visual->red_mask;
-    GMask = visual->green_mask;
-    BMask = visual->blue_mask;
-
-/* GRR:  add/check 8-bit support */
-    if (depth == 8 || need_colormap) {
-        colormap = XCreateColormap(display, root, visual, AllocNone);
-        if (!colormap) {
-            fprintf(stderr, "XCreateColormap() failed\n");
-            return 2;
-        }
-        have_colormap = TRUE;
-        if (depth == 8)
-            bg_image = FALSE;   /* gradient just wastes palette entries */
-    }
-    if (depth == 15 || depth == 16) {
-        RShift = 15 - rpng2_x_msb(RMask);    /* these are right-shifts */
-        GShift = 15 - rpng2_x_msb(GMask);
-        BShift = 15 - rpng2_x_msb(BMask);
-    } else if (depth > 16) {
-        RShift = rpng2_x_msb(RMask) - 7;     /* these are left-shifts */
-        GShift = rpng2_x_msb(GMask) - 7;
-        BShift = rpng2_x_msb(BMask) - 7;
-    }
-    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
-        fprintf(stderr, "rpng2 internal logic error:  negative X shift(s)!\n");
-        return 2;
-    }
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    attr.backing_store = Always;
-    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
-    attrmask = CWBackingStore | CWEventMask;
-    if (have_nondefault_visual) {
-        attr.colormap = colormap;
-        attr.background_pixel = 0;
-        attr.border_pixel = 1;
-        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
-    }
-
-    window = XCreateWindow(display, root, 0, 0, rpng2_info.width,
-      rpng2_info.height, 0, depth, InputOutput, visual, attrmask, &attr);
-
-    if (window == None) {
-        fprintf(stderr, "XCreateWindow() failed\n");
-        return 2;
-    } else
-        have_window = TRUE;
-
-    if (depth == 8)
-        XSetWindowColormap(display, window, colormap);
-
-    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
-        pWindowName = NULL;
-    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
-        pIconName = NULL;
-
-    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
-
-    if ((size_hints = XAllocSizeHints()) != NULL) {
-        /* window will not be resizable */
-        size_hints->flags = PMinSize | PMaxSize;
-        size_hints->min_width = size_hints->max_width = (int)rpng2_info.width;
-        size_hints->min_height = size_hints->max_height =
-          (int)rpng2_info.height;
-    }
-
-    if ((wm_hints = XAllocWMHints()) != NULL) {
-        wm_hints->initial_state = NormalState;
-        wm_hints->input = True;
-     /* wm_hints->icon_pixmap = icon_pixmap; */
-        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
-    }
-
-    if ((class_hints = XAllocClassHint()) != NULL) {
-        class_hints->res_name = res_name;
-        class_hints->res_class = res_class;
-    }
-
-    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
-      size_hints, wm_hints, class_hints);
-
-    /* various properties and hints no longer needed; free memory */
-    if (pWindowName)
-       XFree(pWindowName->value);
-    if (pIconName)
-       XFree(pIconName->value);
-    if (size_hints)
-        XFree(size_hints);
-    if (wm_hints)
-       XFree(wm_hints);
-    if (class_hints)
-       XFree(class_hints);
-
-    XMapWindow(display, window);
-
-    gc = XCreateGC(display, window, 0, &gcvalues);
-    have_gc = TRUE;
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the X- and display-specific version of the image.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        xdata = (uch *)malloc(4*rpng2_info.width*rpng2_info.height);
-        pad = 32;
-    } else if (depth == 16) {
-        xdata = (uch *)malloc(2*rpng2_info.width*rpng2_info.height);
-        pad = 16;
-    } else /* depth == 8 */ {
-        xdata = (uch *)malloc(rpng2_info.width*rpng2_info.height);
-        pad = 8;
-    }
-
-    if (!xdata) {
-        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
-        return 4;
-    }
-
-    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
-      (char *)xdata, rpng2_info.width, rpng2_info.height, pad, 0);
-
-    if (!ximage) {
-        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
-        free(xdata);
-        return 3;
-    }
-
-    /* to avoid testing the byte order every pixel (or doubling the size of
-     * the drawing routine with a giant if-test), we arbitrarily set the byte
-     * order to MSBFirst and let Xlib worry about inverting things on little-
-     * endian machines (e.g., Linux/x86, old VAXen, etc.)--this is not the
-     * most efficient approach (the giant if-test would be better), but in
-     * the interest of clarity, we'll take the easy way out... */
-
-    ximage->byte_order = MSBFirst;
-
-/*---------------------------------------------------------------------------
-    Fill window with the specified background color (default is black) or
-    faked "background image" (but latter is disabled if 8-bit; gradients
-    just waste palette entries).
-  ---------------------------------------------------------------------------*/
-
-    if (bg_image)
-        rpng2_x_load_bg_image();    /* resets bg_image if fails */
-
-    if (!bg_image) {
-        if (depth == 24 || depth == 32) {
-            bg_pixel = (bg_red   << RShift) |
-                       (bg_green << GShift) |
-                       (bg_blue  << BShift);
-        } else if (depth == 16) {
-            bg_pixel = (((bg_red   << 8) >> RShift) & RMask) |
-                       (((bg_green << 8) >> GShift) & GMask) |
-                       (((bg_blue  << 8) >> BShift) & BMask);
-        } else /* depth == 8 */ {
-
-            /* GRR:  add 8-bit support */
-
-        }
-        XSetForeground(display, gc, bg_pixel);
-        XFillRectangle(display, window, gc, 0, 0, rpng2_info.width,
-          rpng2_info.height);
-    }
-
-/*---------------------------------------------------------------------------
-    Wait for first Expose event to do any drawing, then flush and return.
-  ---------------------------------------------------------------------------*/
-
-    do
-        XNextEvent(display, &e);
-    while (e.type != Expose || e.xexpose.count);
-
-    XFlush(display);
-
-    return 0;
-
-} /* end function rpng2_x_create_window() */
-
-
-
-
-
-static int rpng2_x_load_bg_image(void)
-{
-    uch *src;
-    char *dest;
-    uch r1, r2, g1, g2, b1, b2;
-    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
-    int k, hmax, max;
-    int xidx, yidx, yidx_max;
-    int even_odd_vert, even_odd_horiz, even_odd;
-    int invert_gradient2 = (bg[pat].type & 0x08);
-    int invert_column;
-    int ximage_rowbytes = ximage->bytes_per_line;
-    ulg i, row;
-    ulg pixel;
-
-/*---------------------------------------------------------------------------
-    Allocate buffer for fake background image to be used with transparent
-    images; if this fails, revert to plain background color.
-  ---------------------------------------------------------------------------*/
-
-    bg_rowbytes = 3 * rpng2_info.width;
-    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
-    if (!bg_data) {
-        fprintf(stderr, PROGNAME
-          ":  unable to allocate memory for background image\n");
-        bg_image = 0;
-        return 1;
-    }
-
-    bgscale = (pat == 0)? 8 : bgscale_default;
-    yidx_max = bgscale - 1;
-
-/*---------------------------------------------------------------------------
-    Vertical gradients (ramps) in NxN squares, alternating direction and
-    colors (N == bgscale).
-  ---------------------------------------------------------------------------*/
-
-    if ((bg[pat].type & 0x07) == 0) {
-        uch r1_min  = rgb[bg[pat].rgb1_min].r;
-        uch g1_min  = rgb[bg[pat].rgb1_min].g;
-        uch b1_min  = rgb[bg[pat].rgb1_min].b;
-        uch r2_min  = rgb[bg[pat].rgb2_min].r;
-        uch g2_min  = rgb[bg[pat].rgb2_min].g;
-        uch b2_min  = rgb[bg[pat].rgb2_min].b;
-        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
-        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
-        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
-        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
-        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
-        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            even_odd_vert = (int)((row / bgscale) & 1);
-
-            r1 = r1_min + (r1_diff * yidx) / yidx_max;
-            g1 = g1_min + (g1_diff * yidx) / yidx_max;
-            b1 = b1_min + (b1_diff * yidx) / yidx_max;
-            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
-            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
-            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
-
-            r2 = r2_min + (r2_diff * yidx) / yidx_max;
-            g2 = g2_min + (g2_diff * yidx) / yidx_max;
-            b2 = b2_min + (b2_diff * yidx) / yidx_max;
-            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
-            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
-            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
-
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                even_odd_horiz = (int)((i / bgscale) & 1);
-                even_odd = even_odd_vert ^ even_odd_horiz;
-                invert_column =
-                  (even_odd_horiz && (bg[pat].type & 0x10));
-                if (even_odd == 0) {        /* gradient #1 */
-                    if (invert_column) {
-                        *dest++ = r1_inv;
-                        *dest++ = g1_inv;
-                        *dest++ = b1_inv;
-                    } else {
-                        *dest++ = r1;
-                        *dest++ = g1;
-                        *dest++ = b1;
-                    }
-                } else {                    /* gradient #2 */
-                    if ((invert_column && invert_gradient2) ||
-                        (!invert_column && !invert_gradient2))
-                    {
-                        *dest++ = r2;       /* not inverted or */
-                        *dest++ = g2;       /*  doubly inverted */
-                        *dest++ = b2;
-                    } else {
-                        *dest++ = r2_inv;
-                        *dest++ = g2_inv;   /* singly inverted */
-                        *dest++ = b2_inv;
-                    }
-                }
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
-    M. Costello.
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 1) {
-
-        hmax = (bgscale-1)/2;   /* half the max weight of a color */
-        max = 2*hmax;           /* the max weight of a color */
-
-        r1 = rgb[bg[pat].rgb1_max].r;
-        g1 = rgb[bg[pat].rgb1_max].g;
-        b1 = rgb[bg[pat].rgb1_max].b;
-        r2 = rgb[bg[pat].rgb2_max].r;
-        g2 = rgb[bg[pat].rgb2_max].g;
-        b2 = rgb[bg[pat].rgb2_max].b;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            if (yidx > hmax)
-                yidx = bgscale-1 - yidx;
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                xidx = (int)(i % bgscale);
-                if (xidx > hmax)
-                    xidx = bgscale-1 - xidx;
-                k = xidx + yidx;
-                *dest++ = (k*r1 + (max-k)*r2) / max;
-                *dest++ = (k*g1 + (max-k)*g2) / max;
-                *dest++ = (k*b1 + (max-k)*b2) / max;
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
-    soids will equal bgscale?].  This one is slow but very cool.  Code con-
-    tributed by Pieter S. van der Meulen (originally in Smalltalk).
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 2) {
-        uch ch;
-        int ii, x, y, hw, hh, grayspot;
-        double freq, rotate, saturate, gray, intensity;
-        double angle=0.0, aoffset=0.0, maxDist, dist;
-        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
-
-        fprintf(stderr, "%s:  computing radial background...",
-          PROGNAME);
-        fflush(stderr);
-
-        hh = (int)(rpng2_info.height / 2);
-        hw = (int)(rpng2_info.width / 2);
-
-        /* variables for radial waves:
-         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
-         *   freq:  number of color beams originating from the center
-         *   grayspot:  size of the graying center area (anti-alias)
-         *   rotate:  rotation of the beams as a function of radius
-         *   saturate:  saturation of beams' shape azimuthally
-         */
-        angle = CLIP(angle, 0.0, 360.0);
-        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
-        freq = MAX((double)bg[pat].bg_freq, 0.0);
-        saturate = (double)bg[pat].bg_bsat * 0.1;
-        rotate = (double)bg[pat].bg_brot * 0.1;
-        gray = 0.0;
-        intensity = 0.0;
-        maxDist = (double)((hw*hw) + (hh*hh));
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            y = (int)(row - hh);
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                x = (int)(i - hw);
-                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
-                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
-                gray = MIN(1.0, gray);
-                dist = (double)((x*x) + (y*y)) / maxDist;
-                intensity = cos((angle+(rotate*dist*PI)) * freq) *
-                  gray * saturate;
-                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
-                hue = (angle + PI) * INV_PI_360 + aoffset;
-                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
-                s = MIN(MAX(s,0.0), 1.0);
-                v = MIN(MAX(intensity,0.0), 1.0);
-
-                if (s == 0.0) {
-                    ch = (uch)(v * 255.0);
-                    *dest++ = ch;
-                    *dest++ = ch;
-                    *dest++ = ch;
-                } else {
-                    if ((hue < 0.0) || (hue >= 360.0))
-                        hue -= (((int)(hue / 360.0)) * 360.0);
-                    hue /= 60.0;
-                    ii = (int)hue;
-                    f = hue - (double)ii;
-                    p = (1.0 - s) * v;
-                    q = (1.0 - (s * f)) * v;
-                    t = (1.0 - (s * (1.0 - f))) * v;
-                    if      (ii == 0) { red = v; green = t; blue = p; }
-                    else if (ii == 1) { red = q; green = v; blue = p; }
-                    else if (ii == 2) { red = p; green = v; blue = t; }
-                    else if (ii == 3) { red = p; green = q; blue = v; }
-                    else if (ii == 4) { red = t; green = p; blue = v; }
-                    else if (ii == 5) { red = v; green = p; blue = q; }
-                    *dest++ = (uch)(red * 255.0);
-                    *dest++ = (uch)(green * 255.0);
-                    *dest++ = (uch)(blue * 255.0);
-                }
-            }
-        }
-        fprintf(stderr, "done.\n");
-        fflush(stderr);
-    }
-
-/*---------------------------------------------------------------------------
-    Blast background image to display buffer before beginning PNG decode.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-        int bpp = ximage->bits_per_pixel;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            src = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (bpp == 32) {	/* slightly optimized version */
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            } else {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
-                    /*           (probably need to use RShift, RMask, etc.) */
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            src = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                red   = ((ush)(*src) << 8);  ++src;
-                green = ((ush)(*src) << 8);  ++src;
-                blue  = ((ush)(*src) << 8);  ++src;
-                pixel = ((red   >> RShift) & RMask) |
-                        ((green >> GShift) & GMask) |
-                        ((blue  >> BShift) & BMask);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                *dest++ = (char)((pixel >>  8) & 0xff);
-                *dest++ = (char)( pixel        & 0xff);
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    XPutImage(display, window, gc, ximage, 0, 0, 0, 0, rpng2_info.width,
-      rpng2_info.height);
-
-    return 0;
-
-} /* end function rpng2_x_load_bg_image() */
-
-
-
-
-
-static void rpng2_x_display_row(ulg row)
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *src, *src2=NULL;
-    char *dest;
-    uch r, g, b, a;
-    int ximage_rowbytes = ximage->bytes_per_line;
-    ulg i, pixel;
-    static int rows=0, prevpass=(-1);
-    static ulg firstrow;
-
-/*---------------------------------------------------------------------------
-    rows and firstrow simply track how many rows (and which ones) have not
-    yet been displayed; alternatively, we could call XPutImage() for every
-    row and not bother with the records-keeping.
-  ---------------------------------------------------------------------------*/
-
-    Trace((stderr, "beginning rpng2_x_display_row()\n"))
-
-    if (rpng2_info.pass != prevpass) {
-        if (pause_after_pass && rpng2_info.pass > 0) {
-            XEvent e;
-            KeySym k;
-
-            fprintf(stderr,
-              "%s:  end of pass %d of 7; click in image window to continue\n",
-              PROGNAME, prevpass + 1);
-            do
-                XNextEvent(display, &e);
-            while (!QUIT(e,k));
-        }
-        fprintf(stderr, "%s:  pass %d of 7\r", PROGNAME, rpng2_info.pass + 1);
-        fflush(stderr);
-        prevpass = rpng2_info.pass;
-    }
-
-    if (rows == 0)
-        firstrow = row;   /* first row that is not yet displayed */
-
-    ++rows;   /* count of rows received but not yet displayed */
-
-/*---------------------------------------------------------------------------
-    Aside from the use of the rpng2_info struct, the lack of an outer loop
-    (over rows) and moving the XPutImage() call outside the "if (depth)"
-    tests, this routine is identical to rpng_x_display_image() in the non-
-    progressive version of the program.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-        int bpp = ximage->bits_per_pixel;
-
-        src = rpng2_info.image_data + row*rpng2_info.rowbytes;
-        if (bg_image)
-            src2 = bg_data + row*bg_rowbytes;
-        dest = ximage->data + row*ximage_rowbytes;
-        if (rpng2_info.channels == 3) {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                red   = *src++;
-                green = *src++;
-                blue  = *src++;
-                pixel = (red   << RShift) |
-                        (green << GShift) |
-                        (blue  << BShift);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                if (bpp == 32) {
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                } else {
-                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
-                    /*           (probably need to use RShift, RMask, etc.) */
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-        } else /* if (rpng2_info.channels == 4) */ {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (bg_image) {
-                    bg_red   = *src2++;
-                    bg_green = *src2++;
-                    bg_blue  = *src2++;
-                }
-                if (a == 255) {
-                    red   = r;
-                    green = g;
-                    blue  = b;
-                } else if (a == 0) {
-                    red   = bg_red;
-                    green = bg_green;
-                    blue  = bg_blue;
-                } else {
-                    /* this macro (from png.h) composites the foreground
-                     * and background values and puts the result into the
-                     * first argument */
-                    alpha_composite(red,   r, a, bg_red);
-                    alpha_composite(green, g, a, bg_green);
-                    alpha_composite(blue,  b, a, bg_blue);
-                }
-                pixel = (red   << RShift) |
-                        (green << GShift) |
-                        (blue  << BShift);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                if (bpp == 32) {
-                    *dest++ = (char)((pixel >> 24) & 0xff);
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                } else {
-                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
-                    /*           (probably need to use RShift, RMask, etc.) */
-                    *dest++ = (char)((pixel >> 16) & 0xff);
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        src = rpng2_info.row_pointers[row];
-        if (bg_image)
-            src2 = bg_data + row*bg_rowbytes;
-        dest = ximage->data + row*ximage_rowbytes;
-        if (rpng2_info.channels == 3) {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                red   = ((ush)(*src) << 8);
-                ++src;
-                green = ((ush)(*src) << 8);
-                ++src;
-                blue  = ((ush)(*src) << 8);
-                ++src;
-                pixel = ((red   >> RShift) & RMask) |
-                        ((green >> GShift) & GMask) |
-                        ((blue  >> BShift) & BMask);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                *dest++ = (char)((pixel >>  8) & 0xff);
-                *dest++ = (char)( pixel        & 0xff);
-            }
-        } else /* if (rpng2_info.channels == 4) */ {
-            for (i = rpng2_info.width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (bg_image) {
-                    bg_red   = *src2++;
-                    bg_green = *src2++;
-                    bg_blue  = *src2++;
-                }
-                if (a == 255) {
-                    red   = ((ush)r << 8);
-                    green = ((ush)g << 8);
-                    blue  = ((ush)b << 8);
-                } else if (a == 0) {
-                    red   = ((ush)bg_red   << 8);
-                    green = ((ush)bg_green << 8);
-                    blue  = ((ush)bg_blue  << 8);
-                } else {
-                    /* this macro (from png.h) composites the foreground
-                     * and background values and puts the result back into
-                     * the first argument (== fg byte here:  safe) */
-                    alpha_composite(r, r, a, bg_red);
-                    alpha_composite(g, g, a, bg_green);
-                    alpha_composite(b, b, a, bg_blue);
-                    red   = ((ush)r << 8);
-                    green = ((ush)g << 8);
-                    blue  = ((ush)b << 8);
-                }
-                pixel = ((red   >> RShift) & RMask) |
-                        ((green >> GShift) & GMask) |
-                        ((blue  >> BShift) & BMask);
-                /* recall that we set ximage->byte_order = MSBFirst above */
-                *dest++ = (char)((pixel >>  8) & 0xff);
-                *dest++ = (char)( pixel        & 0xff);
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-
-/*---------------------------------------------------------------------------
-    Display after every 16 rows or when on one of last two rows.  (Region
-    may include previously displayed lines due to interlacing--i.e., not
-    contiguous.  Also, second-to-last row is final one in interlaced images
-    with odd number of rows.)  For demos, flush (and delay) after every 16th
-    row so "sparse" passes don't go twice as fast.
-  ---------------------------------------------------------------------------*/
-
-    if (demo_timing && (row - firstrow >= 16 || row >= rpng2_info.height-2)) {
-        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
-          (int)firstrow, rpng2_info.width, row - firstrow + 1);
-        XFlush(display);
-        rows = 0;
-        usleep(usleep_duration);
-    } else
-    if (!demo_timing && ((rows & 0xf) == 0 || row >= rpng2_info.height-2)) {
-        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
-          (int)firstrow, rpng2_info.width, row - firstrow + 1);
-        XFlush(display);
-        rows = 0;
-    }
-
-}
-
-
-
-
-
-static void rpng2_x_finish_display(void)
-{
-    Trace((stderr, "beginning rpng2_x_finish_display()\n"))
-
-    /* last row has already been displayed by rpng2_x_display_row(), so we
-     * have nothing to do here except set a flag and let the user know that
-     * the image is done */
-
-    rpng2_info.state = kDone;
-    printf(
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
-    fflush(stdout);
-}
-
-
-
-
-
-static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
-                                    ulg width, ulg height)
-{
-    uch bg_red   = rpng2_info.bg_red;
-    uch bg_green = rpng2_info.bg_green;
-    uch bg_blue  = rpng2_info.bg_blue;
-    uch *src, *src2=NULL;
-    char *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow = 0;
-    ulg pixel;
-    int ximage_rowbytes = ximage->bytes_per_line;
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      rpng2_info.channels))
-    Trace((stderr, "   (width = %ld, rowbytes = %d, ximage_rowbytes = %d)\n",
-      rpng2_info.width, rpng2_info.rowbytes, ximage_rowbytes))
-    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
-    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
-      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
-
-/*---------------------------------------------------------------------------
-    Aside from the use of the rpng2_info struct and of src2 (for background
-    image), this routine is identical to rpng_x_display_image() in the non-
-    progressive version of the program--for the simple reason that redisplay
-    of the image against a new background happens after the image is fully
-    decoded and therefore is, by definition, non-progressive.
-  ---------------------------------------------------------------------------*/
-
-    if (depth == 24 || depth == 32) {
-        ulg red, green, blue;
-        int bpp = ximage->bits_per_pixel;
-
-        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
-            src = rpng2_info.image_data + row*rpng2_info.rowbytes;
-            if (bg_image)
-                src2 = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (rpng2_info.channels == 3) {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = *src++;
-                    green = *src++;
-                    blue  = *src++;
-#ifdef NO_24BIT_MASKS
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift, RMask, etc.) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#else
-                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
-                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
-                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
-                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* GRR BUG */
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift/RMask/etc. here, too) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#endif
-                }
-
-            } else /* if (rpng2_info.channels == 4) */ {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (bg_image) {
-                        bg_red   = *src2++;
-                        bg_green = *src2++;
-                        bg_blue  = *src2++;
-                    }
-                    if (a == 255) {
-                        red   = r;
-                        green = g;
-                        blue  = b;
-                    } else if (a == 0) {
-                        red   = bg_red;
-                        green = bg_green;
-                        blue  = bg_blue;
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result into the
-                         * first argument */
-                        alpha_composite(red,   r, a, bg_red);
-                        alpha_composite(green, g, a, bg_green);
-                        alpha_composite(blue,  b, a, bg_blue);
-                    }
-#ifdef NO_24BIT_MASKS
-                    pixel = (red   << RShift) |
-                            (green << GShift) |
-                            (blue  << BShift);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift, RMask, etc.) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#else
-                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
-                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
-                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
-                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    if (bpp == 32) {
-                        *dest++ = (char)((pixel >> 24) & 0xff);
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    } else {
-                        /* GRR BUG */
-                        /* this assumes bpp == 24 & bits are packed low */
-                        /* (probably need to use RShift/RMask/etc. here, too) */
-                        *dest++ = (char)((pixel >> 16) & 0xff);
-                        *dest++ = (char)((pixel >>  8) & 0xff);
-                        *dest++ = (char)( pixel        & 0xff);
-                    }
-#endif
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, rpng2_info.width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else if (depth == 16) {
-        ush red, green, blue;
-
-        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
-            src = rpng2_info.row_pointers[row];
-            if (bg_image)
-                src2 = bg_data + row*bg_rowbytes;
-            dest = ximage->data + row*ximage_rowbytes;
-            if (rpng2_info.channels == 3) {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    red   = ((ush)(*src) << 8);
-                    ++src;
-                    green = ((ush)(*src) << 8);
-                    ++src;
-                    blue  = ((ush)(*src) << 8);
-                    ++src;
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            } else /* if (rpng2_info.channels == 4) */ {
-                for (i = rpng2_info.width;  i > 0;  --i) {
-                    r = *src++;
-                    g = *src++;
-                    b = *src++;
-                    a = *src++;
-                    if (bg_image) {
-                        bg_red   = *src2++;
-                        bg_green = *src2++;
-                        bg_blue  = *src2++;
-                    }
-                    if (a == 255) {
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    } else if (a == 0) {
-                        red   = ((ush)bg_red   << 8);
-                        green = ((ush)bg_green << 8);
-                        blue  = ((ush)bg_blue  << 8);
-                    } else {
-                        /* this macro (from png.h) composites the foreground
-                         * and background values and puts the result back into
-                         * the first argument (== fg byte here:  safe) */
-                        alpha_composite(r, r, a, bg_red);
-                        alpha_composite(g, g, a, bg_green);
-                        alpha_composite(b, b, a, bg_blue);
-                        red   = ((ush)r << 8);
-                        green = ((ush)g << 8);
-                        blue  = ((ush)b << 8);
-                    }
-                    pixel = ((red   >> RShift) & RMask) |
-                            ((green >> GShift) & GMask) |
-                            ((blue  >> BShift) & BMask);
-                    /* recall that we set ximage->byte_order = MSBFirst above */
-                    *dest++ = (char)((pixel >>  8) & 0xff);
-                    *dest++ = (char)( pixel        & 0xff);
-                }
-            }
-            /* display after every 16 lines */
-            if (((row+1) & 0xf) == 0) {
-                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-                  (int)lastrow, rpng2_info.width, 16);
-                XFlush(display);
-                lastrow = row + 1;
-            }
-        }
-
-    } else /* depth == 8 */ {
-
-        /* GRR:  add 8-bit support */
-
-    }
-
-    Trace((stderr, "calling final XPutImage()\n"))
-    if (lastrow < startrow+height) {
-        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
-          (int)lastrow, rpng2_info.width, rpng2_info.height-lastrow);
-        XFlush(display);
-    }
-
-} /* end function rpng2_x_redisplay_image() */
-
-
-
-
-
-#ifdef FEATURE_LOOP
-
-static void rpng2_x_reload_bg_image(void)
-{
-    char *dest;
-    uch r1, r2, g1, g2, b1, b2;
-    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
-    int k, hmax, max;
-    int xidx, yidx, yidx_max;
-    int even_odd_vert, even_odd_horiz, even_odd;
-    int invert_gradient2 = (bg[pat].type & 0x08);
-    int invert_column;
-    ulg i, row;
-
-
-    bgscale = (pat == 0)? 8 : bgscale_default;
-    yidx_max = bgscale - 1;
-
-/*---------------------------------------------------------------------------
-    Vertical gradients (ramps) in NxN squares, alternating direction and
-    colors (N == bgscale).
-  ---------------------------------------------------------------------------*/
-
-    if ((bg[pat].type & 0x07) == 0) {
-        uch r1_min  = rgb[bg[pat].rgb1_min].r;
-        uch g1_min  = rgb[bg[pat].rgb1_min].g;
-        uch b1_min  = rgb[bg[pat].rgb1_min].b;
-        uch r2_min  = rgb[bg[pat].rgb2_min].r;
-        uch g2_min  = rgb[bg[pat].rgb2_min].g;
-        uch b2_min  = rgb[bg[pat].rgb2_min].b;
-        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
-        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
-        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
-        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
-        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
-        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            even_odd_vert = (int)((row / bgscale) & 1);
-
-            r1 = r1_min + (r1_diff * yidx) / yidx_max;
-            g1 = g1_min + (g1_diff * yidx) / yidx_max;
-            b1 = b1_min + (b1_diff * yidx) / yidx_max;
-            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
-            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
-            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
-
-            r2 = r2_min + (r2_diff * yidx) / yidx_max;
-            g2 = g2_min + (g2_diff * yidx) / yidx_max;
-            b2 = b2_min + (b2_diff * yidx) / yidx_max;
-            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
-            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
-            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
-
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                even_odd_horiz = (int)((i / bgscale) & 1);
-                even_odd = even_odd_vert ^ even_odd_horiz;
-                invert_column =
-                  (even_odd_horiz && (bg[pat].type & 0x10));
-                if (even_odd == 0) {        /* gradient #1 */
-                    if (invert_column) {
-                        *dest++ = r1_inv;
-                        *dest++ = g1_inv;
-                        *dest++ = b1_inv;
-                    } else {
-                        *dest++ = r1;
-                        *dest++ = g1;
-                        *dest++ = b1;
-                    }
-                } else {                    /* gradient #2 */
-                    if ((invert_column && invert_gradient2) ||
-                        (!invert_column && !invert_gradient2))
-                    {
-                        *dest++ = r2;       /* not inverted or */
-                        *dest++ = g2;       /*  doubly inverted */
-                        *dest++ = b2;
-                    } else {
-                        *dest++ = r2_inv;
-                        *dest++ = g2_inv;   /* singly inverted */
-                        *dest++ = b2_inv;
-                    }
-                }
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
-    M. Costello.
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 1) {
-
-        hmax = (bgscale-1)/2;   /* half the max weight of a color */
-        max = 2*hmax;           /* the max weight of a color */
-
-        r1 = rgb[bg[pat].rgb1_max].r;
-        g1 = rgb[bg[pat].rgb1_max].g;
-        b1 = rgb[bg[pat].rgb1_max].b;
-        r2 = rgb[bg[pat].rgb2_max].r;
-        g2 = rgb[bg[pat].rgb2_max].g;
-        b2 = rgb[bg[pat].rgb2_max].b;
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            yidx = (int)(row % bgscale);
-            if (yidx > hmax)
-                yidx = bgscale-1 - yidx;
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                xidx = (int)(i % bgscale);
-                if (xidx > hmax)
-                    xidx = bgscale-1 - xidx;
-                k = xidx + yidx;
-                *dest++ = (k*r1 + (max-k)*r2) / max;
-                *dest++ = (k*g1 + (max-k)*g2) / max;
-                *dest++ = (k*b1 + (max-k)*b2) / max;
-            }
-        }
-
-/*---------------------------------------------------------------------------
-    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
-    soids will equal bgscale?].  This one is slow but very cool.  Code con-
-    tributed by Pieter S. van der Meulen (originally in Smalltalk).
-  ---------------------------------------------------------------------------*/
-
-    } else if ((bg[pat].type & 0x07) == 2) {
-        uch ch;
-        int ii, x, y, hw, hh, grayspot;
-        double freq, rotate, saturate, gray, intensity;
-        double angle=0.0, aoffset=0.0, maxDist, dist;
-        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
-
-        hh = (int)(rpng2_info.height / 2);
-        hw = (int)(rpng2_info.width / 2);
-
-        /* variables for radial waves:
-         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
-         *   freq:  number of color beams originating from the center
-         *   grayspot:  size of the graying center area (anti-alias)
-         *   rotate:  rotation of the beams as a function of radius
-         *   saturate:  saturation of beams' shape azimuthally
-         */
-        angle = CLIP(angle, 0.0, 360.0);
-        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
-        freq = MAX((double)bg[pat].bg_freq, 0.0);
-        saturate = (double)bg[pat].bg_bsat * 0.1;
-        rotate = (double)bg[pat].bg_brot * 0.1;
-        gray = 0.0;
-        intensity = 0.0;
-        maxDist = (double)((hw*hw) + (hh*hh));
-
-        for (row = 0;  row < rpng2_info.height;  ++row) {
-            y = (int)(row - hh);
-            dest = (char *)bg_data + row*bg_rowbytes;
-            for (i = 0;  i < rpng2_info.width;  ++i) {
-                x = (int)(i - hw);
-                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
-                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
-                gray = MIN(1.0, gray);
-                dist = (double)((x*x) + (y*y)) / maxDist;
-                intensity = cos((angle+(rotate*dist*PI)) * freq) *
-                  gray * saturate;
-                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
-                hue = (angle + PI) * INV_PI_360 + aoffset;
-                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
-                s = MIN(MAX(s,0.0), 1.0);
-                v = MIN(MAX(intensity,0.0), 1.0);
-
-                if (s == 0.0) {
-                    ch = (uch)(v * 255.0);
-                    *dest++ = ch;
-                    *dest++ = ch;
-                    *dest++ = ch;
-                } else {
-                    if ((hue < 0.0) || (hue >= 360.0))
-                        hue -= (((int)(hue / 360.0)) * 360.0);
-                    hue /= 60.0;
-                    ii = (int)hue;
-                    f = hue - (double)ii;
-                    p = (1.0 - s) * v;
-                    q = (1.0 - (s * f)) * v;
-                    t = (1.0 - (s * (1.0 - f))) * v;
-                    if      (ii == 0) { red = v; green = t; blue = p; }
-                    else if (ii == 1) { red = q; green = v; blue = p; }
-                    else if (ii == 2) { red = p; green = v; blue = t; }
-                    else if (ii == 3) { red = p; green = q; blue = v; }
-                    else if (ii == 4) { red = t; green = p; blue = v; }
-                    else if (ii == 5) { red = v; green = p; blue = q; }
-                    *dest++ = (uch)(red * 255.0);
-                    *dest++ = (uch)(green * 255.0);
-                    *dest++ = (uch)(blue * 255.0);
-                }
-            }
-        }
-    }
-
-} /* end function rpng2_x_reload_bg_image() */
-
-
-
-
-
-static int is_number(char *p)
-{
-    while (*p) {
-        if (!isdigit(*p))
-            return FALSE;
-        ++p;
-    }
-    return TRUE;
-}
-
-#endif /* FEATURE_LOOP */
-
-
-
-
-
-static void rpng2_x_cleanup(void)
-{
-    if (bg_image && bg_data) {
-        free(bg_data);
-        bg_data = NULL;
-    }
-
-    if (rpng2_info.image_data) {
-        free(rpng2_info.image_data);
-        rpng2_info.image_data = NULL;
-    }
-
-    if (rpng2_info.row_pointers) {
-        free(rpng2_info.row_pointers);
-        rpng2_info.row_pointers = NULL;
-    }
-
-    if (ximage) {
-        if (ximage->data) {
-            free(ximage->data);           /* we allocated it, so we free it */
-            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
-        }
-        XDestroyImage(ximage);
-        ximage = NULL;
-    }
-
-    if (have_gc)
-        XFreeGC(display, gc);
-
-    if (have_window)
-        XDestroyWindow(display, window);
-
-    if (have_colormap)
-        XFreeColormap(display, colormap);
-
-    if (have_nondefault_visual)
-        XFree(visual_list);
-}
-
-
-
-
-
-static int rpng2_x_msb(ulg u32val)
-{
-    int i;
-
-    for (i = 31;  i >= 0;  --i) {
-        if (u32val & 0x80000000L)
-            break;
-        u32val <<= 1;
-    }
-    return i;
-}
diff --git a/contrib/gregbook/toucan.png b/contrib/gregbook/toucan.png
deleted file mode 100644
index 03960d4..0000000
--- a/contrib/gregbook/toucan.png
+++ /dev/null
diff --git a/contrib/gregbook/wpng.c b/contrib/gregbook/wpng.c
deleted file mode 100644
index a06e352..0000000
--- a/contrib/gregbook/wpng.c
+++ /dev/null
@@ -1,853 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   wpng - simple PNG-writing program                                 wpng.c
-
-   This program converts certain NetPBM binary files (grayscale and RGB,
-   maxval = 255) to PNG.  Non-interlaced PNGs are written progressively;
-   interlaced PNGs are read and written in one memory-intensive blast.
-
-   Thanks to Jean-loup Gailly for providing the necessary trick to read
-   interactive text from the keyboard while stdin is redirected.  Thanks
-   to Cosmin Truta for Cygwin fixes.
-
-   NOTE:  includes provisional support for PNM type "8" (portable alphamap)
-          images, presumed to be a 32-bit interleaved RGBA format; no pro-
-          vision for possible interleaved grayscale+alpha (16-bit) format.
-          THIS IS UNLIKELY TO BECOME AN OFFICIAL NETPBM ALPHA FORMAT!
-
-   to do:
-    - delete output file if quit before calling any writepng routines
-    - process backspace with -text option under DOS/Win? (currently get ^H)
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options
-    - 1.03:  removed extraneous character from usage screen; fixed bug in
-              command-line parsing
-    - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
-              (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
-    - 2.00:  dual-licensed (added GNU GPL)
-
-        [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
-         dose not work!  In order to do something useful I needed to redirect
-         both input and output, with cygwin and with bcc32 as well.  Under
-         Linux, the same wpng appears to work fine.  I don't know what is
-         the problem."]
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "wpng"
-#define VERSION   "2.00 of 2 June 2007"
-#define APPNAME   "Simple PGM/PPM/PAM to PNG Converter"
-
-#if defined(__MSDOS__) || defined(__OS2__)
-#  define DOS_OS2_W32
-#elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
-#  ifndef __GNUC__   /* treat Win32 native ports of gcc as Unix environments */
-#    define DOS_OS2_W32
-#  endif
-#endif
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <setjmp.h>     /* for jmpbuf declaration in writepng.h */
-#include <time.h>
-
-#ifdef DOS_OS2_W32
-#  include <io.h>       /* for isatty(), setmode() prototypes */
-#  include <fcntl.h>    /* O_BINARY for fdopen() without text translation */
-#  ifdef __EMX__
-#    ifndef getch
-#      define getch() _read_kbd(0, 1, 0)    /* need getche() */
-#    endif
-#  else /* !__EMX__ */
-#    ifdef __GO32__
-#      include <pc.h>
-#      define getch() getkey()  /* GRR:  need getche() */
-#    else
-#      include <conio.h>        /* for getche() console input */
-#    endif
-#  endif /* ?__EMX__ */
-#  define FGETS(buf,len,stream)  dos_kbd_gets(buf,len)
-#else
-#  include <unistd.h>           /* for isatty() prototype */
-#  define FGETS fgets
-#endif
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-/* #define FORBID_LATIN1_CTRL  :  this requires the user to re-enter any
-   text that includes control characters discouraged by the PNG spec; text
-   that includes an escape character (27) must be re-entered regardless */
-
-#include "writepng.h"   /* typedefs, common macros, writepng prototypes */
-
-
-
-/* local prototypes */
-
-static int  wpng_isvalid_latin1(uch *p, int len);
-static void wpng_cleanup(void);
-
-#ifdef DOS_OS2_W32
-   static char *dos_kbd_gets(char *buf, int len);
-#endif
-
-
-
-static mainprog_info wpng_info;   /* lone global */
-
-
-
-int main(int argc, char **argv)
-{
-#ifndef DOS_OS2_W32
-    FILE *keybd;
-#endif
-#ifdef sgi
-    FILE *tmpfile;      /* or we could just use keybd, since no overlap */
-    char tmpline[80];
-#endif
-    char *inname = NULL, outname[256];
-    char *p, pnmchar, pnmline[256];
-    char *bgstr, *textbuf = NULL;
-    ulg rowbytes;
-    int rc, len = 0;
-    int error = 0;
-    int text = FALSE;
-    int maxval;
-    double LUT_exponent;                /* just the lookup table */
-    double CRT_exponent = 2.2;          /* just the monitor */
-    double default_display_exponent;    /* whole display system */
-    double default_gamma = 0.0;
-
-
-    wpng_info.infile = NULL;
-    wpng_info.outfile = NULL;
-    wpng_info.image_data = NULL;
-    wpng_info.row_pointers = NULL;
-    wpng_info.filter = FALSE;
-    wpng_info.interlaced = FALSE;
-    wpng_info.have_bg = FALSE;
-    wpng_info.have_time = FALSE;
-    wpng_info.have_text = 0;
-    wpng_info.gamma = 0.0;
-
-
-    /* First get the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  If the PNM image
-     * looks correct on the user's display system, its file gamma is the
-     * inverse of this value.  (Note that this is not an exhaustive list
-     * of LUT values--e.g., OpenStep has a lot of weird ones--but it should
-     * cover 99% of the current possibilities.  This section must ensure
-     * that default_display_exponent is positive.) */
-
-#if defined(NeXT)
-    /* third-party utilities can modify the default LUT exponent */
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to
-     * get the "gamma" value, so we do it the hard way */
-    tmpfile = fopen("/etc/config/system.glGammaVal", "r");
-    if (tmpfile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, tmpfile);
-        fclose(tmpfile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL) {
-        double exponent = atof(p);
-
-        if (exponent > 0.0)
-            default_gamma = 1.0 / exponent;
-    }
-
-    if (default_gamma == 0.0)
-        default_gamma = 1.0 / default_display_exponent;
-
-
-    /* Now parse the command line for options and the PNM filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-i", 2)) {
-            wpng_info.interlaced = TRUE;
-        } else if (!strncmp(*argv, "-time", 3)) {
-            wpng_info.modtime = time(NULL);
-            wpng_info.have_time = TRUE;
-        } else if (!strncmp(*argv, "-text", 3)) {
-            text = TRUE;
-        } else if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                wpng_info.gamma = atof(*argv);
-                if (wpng_info.gamma <= 0.0)
-                    ++error;
-                else if (wpng_info.gamma > 1.01)
-                    fprintf(stderr, PROGNAME
-                      " warning:  file gammas are usually less than 1.0\n");
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 4)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else {
-                    unsigned r, g, b;  /* this way quiets compiler warnings */
-
-                    sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-                    wpng_info.bg_red   = (uch)r;
-                    wpng_info.bg_green = (uch)g;
-                    wpng_info.bg_blue  = (uch)b;
-                    wpng_info.have_bg = TRUE;
-                }
-            }
-        } else {
-            if (**argv != '-') {
-                inname = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-
-    /* open the input and output files, or register an error and abort */
-
-    if (!inname) {
-        if (isatty(0)) {
-            fprintf(stderr, PROGNAME
-              ":  must give input filename or provide image data via stdin\n");
-            ++error;
-        } else {
-#ifdef DOS_OS2_W32
-            /* some buggy C libraries require BOTH setmode() and fdopen(bin) */
-            setmode(fileno(stdin), O_BINARY);
-            setmode(fileno(stdout), O_BINARY);
-#endif
-            if ((wpng_info.infile = fdopen(fileno(stdin), "rb")) == NULL) {
-                fprintf(stderr, PROGNAME
-                  ":  unable to reopen stdin in binary mode\n");
-                ++error;
-            } else
-            if ((wpng_info.outfile = fdopen(fileno(stdout), "wb")) == NULL) {
-                fprintf(stderr, PROGNAME
-                  ":  unable to reopen stdout in binary mode\n");
-                fclose(wpng_info.infile);
-                ++error;
-            } else
-                wpng_info.filter = TRUE;
-        }
-    } else if ((len = strlen(inname)) > 250) {
-        fprintf(stderr, PROGNAME ":  input filename is too long [%d chars]\n",
-          len);
-        ++error;
-    } else if (!(wpng_info.infile = fopen(inname, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open input file [%s]\n", inname);
-        ++error;
-    }
-
-    if (!error) {
-        fgets(pnmline, 256, wpng_info.infile);
-        if (pnmline[0] != 'P' || ((pnmchar = pnmline[1]) != '5' &&
-            pnmchar != '6' && pnmchar != '8'))
-        {
-            fprintf(stderr, PROGNAME
-              ":  input file [%s] is not a binary PGM, PPM or PAM file\n",
-              inname);
-            ++error;
-        } else {
-            wpng_info.pnmtype = (int)(pnmchar - '0');
-            if (wpng_info.pnmtype != 8)
-                wpng_info.have_bg = FALSE;  /* no need for bg if opaque */
-            do {
-                fgets(pnmline, 256, wpng_info.infile);  /* lose any comments */
-            } while (pnmline[0] == '#');
-            sscanf(pnmline, "%ld %ld", &wpng_info.width, &wpng_info.height);
-            do {
-                fgets(pnmline, 256, wpng_info.infile);  /* more comment lines */
-            } while (pnmline[0] == '#');
-            sscanf(pnmline, "%d", &maxval);
-            if (wpng_info.width <= 0L || wpng_info.height <= 0L ||
-                maxval != 255)
-            {
-                fprintf(stderr, PROGNAME
-                  ":  only positive width/height, maxval == 255 allowed \n");
-                ++error;
-            }
-            wpng_info.sample_depth = 8;  /* <==> maxval 255 */
-
-            if (!wpng_info.filter) {
-                /* make outname from inname */
-                if ((p = strrchr(inname, '.')) == NULL ||
-                    (p - inname) != (len - 4))
-                {
-                    strcpy(outname, inname);
-                    strcpy(outname+len, ".png");
-                } else {
-                    len -= 4;
-                    strncpy(outname, inname, len);
-                    strcpy(outname+len, ".png");
-                }
-                /* check if outname already exists; if not, open */
-                if ((wpng_info.outfile = fopen(outname, "rb")) != NULL) {
-                    fprintf(stderr, PROGNAME ":  output file exists [%s]\n",
-                      outname);
-                    fclose(wpng_info.outfile);
-                    ++error;
-                } else if (!(wpng_info.outfile = fopen(outname, "wb"))) {
-                    fprintf(stderr, PROGNAME ":  can't open output file [%s]\n",
-                      outname);
-                    ++error;
-                }
-            }
-        }
-        if (error) {
-            fclose(wpng_info.infile);
-            wpng_info.infile = NULL;
-            if (wpng_info.filter) {
-                fclose(wpng_info.outfile);
-                wpng_info.outfile = NULL;
-            }
-        }
-    }
-
-
-    /* if we had any errors, print usage and die horrible death...arrr! */
-
-    if (error) {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, APPNAME);
-        writepng_version_info();
-        fprintf(stderr, "\n"
-"Usage:  %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] pnmfile\n"
-"or: ... | %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] | ...\n"
-         "    exp \ttransfer-function exponent (``gamma'') of the image in\n"
-         "\t\t  floating-point format (e.g., ``%.5f''); if image looks\n"
-         "\t\t  correct on given display system, image gamma is equal to\n"
-         "\t\t  inverse of display-system exponent, i.e., 1 / (LUT * CRT)\n"
-         "\t\t  (where LUT = lookup-table exponent and CRT = CRT exponent;\n"
-         "\t\t  first varies, second is usually 2.2, all are positive)\n"
-         "    bg  \tdesired background color for alpha-channel images, in\n"
-         "\t\t  7-character hex RGB format (e.g., ``#ff7700'' for orange:\n"
-         "\t\t  same as HTML colors)\n"
-         "    -text\tprompt interactively for text info (tEXt chunks)\n"
-         "    -time\tinclude a tIME chunk (last modification time)\n"
-         "    -interlace\twrite interlaced PNG image\n"
-         "\n"
-"pnmfile or stdin must be a binary PGM (`P5'), PPM (`P6') or (extremely\n"
-"unofficial and unsupported!) PAM (`P8') file.  Currently it is required\n"
-"to have maxval == 255 (i.e., no scaling).  If pnmfile is specified, it\n"
-"is converted to the corresponding PNG file with the same base name but a\n"
-"``.png'' extension; files read from stdin are converted and sent to stdout.\n"
-"The conversion is progressive (low memory usage) unless interlacing is\n"
-"requested; in that case the whole image will be buffered in memory and\n"
-"written in one call.\n"
-         "\n", PROGNAME, PROGNAME, default_gamma);
-        exit(1);
-    }
-
-
-    /* prepare the text buffers for libpng's use; note that even though
-     * PNG's png_text struct includes a length field, we don't have to fill
-     * it out */
-
-    if (text &&
-#ifndef DOS_OS2_W32
-        (keybd = fdopen(fileno(stderr), "r")) != NULL &&
-#endif
-        (textbuf = (char *)malloc((5 + 9)*75)) != NULL)
-    {
-        int i, valid, result;
-
-        fprintf(stderr,
-          "Enter text info (no more than 72 characters per line);\n");
-        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
-        /* note:  just <Enter> leaves len == 1 */
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_TITLE_OFFSET;
-            fprintf(stderr, "  Title: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.title = p;
-                wpng_info.have_text |= TEXT_TITLE;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_TITLE;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_TITLE;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_AUTHOR_OFFSET;
-            fprintf(stderr, "  Author: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.author = p;
-                wpng_info.have_text |= TEXT_AUTHOR;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_AUTHOR;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_AUTHOR;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_DESC_OFFSET;
-            fprintf(stderr, "  Description (up to 9 lines):\n");
-            for (i = 1;  i < 10;  ++i) {
-                fprintf(stderr, "    [%d] ", i);
-                fflush(stderr);
-                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
-                    p += len;   /* now points at NULL; char before is newline */
-                else
-                    break;
-            }
-            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
-                if (p[-1] == '\n') {
-                    p[-1] = '\0';
-                    --len;
-                }
-                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
-                wpng_info.have_text |= TEXT_DESC;
-                p = textbuf + TEXT_DESC_OFFSET;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_DESC;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_DESC;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_COPY_OFFSET;
-            fprintf(stderr, "  Copyright: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.copyright = p;
-                wpng_info.have_text |= TEXT_COPY;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_COPY;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_COPY;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_EMAIL_OFFSET;
-            fprintf(stderr, "  E-mail: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.email = p;
-                wpng_info.have_text |= TEXT_EMAIL;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_EMAIL;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_EMAIL;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-        do {
-            valid = TRUE;
-            p = textbuf + TEXT_URL_OFFSET;
-            fprintf(stderr, "  URL: ");
-            fflush(stderr);
-            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
-                if (p[len-1] == '\n')
-                    p[--len] = '\0';
-                wpng_info.url = p;
-                wpng_info.have_text |= TEXT_URL;
-                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
-                    fprintf(stderr, "    " PROGNAME " warning:  character code"
-                      " %u is %sdiscouraged by the PNG\n    specification "
-                      "[first occurrence was at character position #%d]\n",
-                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
-                      result+1);
-                    fflush(stderr);
-#ifdef FORBID_LATIN1_CTRL
-                    wpng_info.have_text &= ~TEXT_URL;
-                    valid = FALSE;
-#else
-                    if (p[result] == 27) {    /* escape character */
-                        wpng_info.have_text &= ~TEXT_URL;
-                        valid = FALSE;
-                    }
-#endif
-                }
-            }
-        } while (!valid);
-
-#ifndef DOS_OS2_W32
-        fclose(keybd);
-#endif
-
-    } else if (text) {
-        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
-        text = FALSE;
-        wpng_info.have_text = 0;
-    }
-
-
-    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */
-
-    if ((rc = writepng_init(&wpng_info)) != 0) {
-        switch (rc) {
-            case 2:
-                fprintf(stderr, PROGNAME
-                  ":  libpng initialization problem (longjmp)\n");
-                break;
-            case 4:
-                fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                break;
-            case 11:
-                fprintf(stderr, PROGNAME
-                  ":  internal logic error (unexpected PNM type)\n");
-                break;
-            default:
-                fprintf(stderr, PROGNAME
-                  ":  unknown writepng_init() error\n");
-                break;
-        }
-        exit(rc);
-    }
-
-
-    /* free textbuf, since it's a completely local variable and all text info
-     * has just been written to the PNG file */
-
-    if (text && textbuf) {
-        free(textbuf);
-        textbuf = NULL;
-    }
-
-
-    /* calculate rowbytes on basis of image type; note that this becomes much
-     * more complicated if we choose to support PBM type, ASCII PNM types, or
-     * 16-bit-per-sample binary data [currently not an official NetPBM type] */
-
-    if (wpng_info.pnmtype == 5)
-        rowbytes = wpng_info.width;
-    else if (wpng_info.pnmtype == 6)
-        rowbytes = wpng_info.width * 3;
-    else /* if (wpng_info.pnmtype == 8) */
-        rowbytes = wpng_info.width * 4;
-
-
-    /* read and write the image, either in its entirety (if writing interlaced
-     * PNG) or row by row (if non-interlaced) */
-
-    fprintf(stderr, "Encoding image data...\n");
-    fflush(stderr);
-
-    if (wpng_info.interlaced) {
-        long i;
-        ulg bytes;
-        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */
-
-        wpng_info.image_data = (uch *)malloc(image_bytes);
-        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
-        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
-            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(5);
-        }
-        for (i = 0;  i < wpng_info.height;  ++i)
-            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
-        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
-        if (bytes != image_bytes) {
-            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
-              image_bytes, bytes);
-            fprintf(stderr, "  (continuing anyway)\n");
-        }
-        if (writepng_encode_image(&wpng_info) != 0) {
-            fprintf(stderr, PROGNAME
-              ":  libpng problem (longjmp) while writing image data\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(2);
-        }
-
-    } else /* not interlaced:  write progressively (row by row) */ {
-        long j;
-        ulg bytes;
-
-        wpng_info.image_data = (uch *)malloc(rowbytes);
-        if (wpng_info.image_data == NULL) {
-            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(5);
-        }
-        error = 0;
-        for (j = wpng_info.height;  j > 0L;  --j) {
-            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
-            if (bytes != rowbytes) {
-                fprintf(stderr, PROGNAME
-                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
-                  bytes, wpng_info.height-j);
-                ++error;
-                break;
-            }
-            if (writepng_encode_row(&wpng_info) != 0) {
-                fprintf(stderr, PROGNAME
-                  ":  libpng problem (longjmp) while writing row %ld\n",
-                  wpng_info.height-j);
-                ++error;
-                break;
-            }
-        }
-        if (error) {
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(2);
-        }
-        if (writepng_encode_finish(&wpng_info) != 0) {
-            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
-            writepng_cleanup(&wpng_info);
-            wpng_cleanup();
-            exit(2);
-        }
-    }
-
-
-    /* OK, we're done (successfully):  clean up all resources and quit */
-
-    fprintf(stderr, "Done.\n");
-    fflush(stderr);
-
-    writepng_cleanup(&wpng_info);
-    wpng_cleanup();
-
-    return 0;
-}
-
-
-
-
-
-static int wpng_isvalid_latin1(uch *p, int len)
-{
-    int i, result = -1;
-
-    for (i = 0;  i < len;  ++i) {
-        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
-            continue;           /* character is completely OK */
-        if (result < 0 || (p[result] != 27 && p[i] == 27))
-            result = i;         /* mark location of first questionable one */
-    }                           /*  or of first escape character (bad) */
-
-    return result;
-}
-
-
-
-
-
-static void wpng_cleanup(void)
-{
-    if (wpng_info.outfile) {
-        fclose(wpng_info.outfile);
-        wpng_info.outfile = NULL;
-    }
-
-    if (wpng_info.infile) {
-        fclose(wpng_info.infile);
-        wpng_info.infile = NULL;
-    }
-
-    if (wpng_info.image_data) {
-        free(wpng_info.image_data);
-        wpng_info.image_data = NULL;
-    }
-
-    if (wpng_info.row_pointers) {
-        free(wpng_info.row_pointers);
-        wpng_info.row_pointers = NULL;
-    }
-}
-
-
-
-
-#ifdef DOS_OS2_W32
-
-static char *dos_kbd_gets(char *buf, int len)
-{
-    int ch, count=0;
-
-    do {
-        buf[count++] = ch = getche();
-    } while (ch != '\r' && count < len-1);
-
-    buf[count--] = '\0';        /* terminate string */
-    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
-        buf[count] = '\n';
-
-    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
-    fflush(stderr);
-
-    return buf;
-}
-
-#endif /* DOS_OS2_W32 */
diff --git a/contrib/gregbook/writepng.c b/contrib/gregbook/writepng.c
deleted file mode 100644
index e6d81ea..0000000
--- a/contrib/gregbook/writepng.c
+++ /dev/null
@@ -1,392 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   wpng - simple PNG-writing program                             writepng.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-
-#include <stdlib.h>     /* for exit() prototype */
-
-#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
-#include "writepng.h"   /* typedefs, common macros, public prototypes */
-
-
-/* local prototype */
-
-static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
-
-
-
-void writepng_version_info(void)
-{
-  fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
-    PNG_LIBPNG_VER_STRING, png_libpng_ver);
-  fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
-    ZLIB_VERSION, zlib_version);
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
- *  unexpected pnmtype; note that outfile might be stdout */
-
-int writepng_init(mainprog_info *mainprog_ptr)
-{
-    png_structp  png_ptr;       /* note:  temporary variables! */
-    png_infop  info_ptr;
-    int color_type, interlace_type;
-
-
-    /* could also replace libpng warning-handler (final NULL), but no need: */
-
-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
-      writepng_error_handler, NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_write_struct(&png_ptr, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* setjmp() must be called in every function that calls a PNG-writing
-     * libpng function, unless an alternate error handler was installed--
-     * but compatible error handlers must either use longjmp() themselves
-     * (as in this program) or exit immediately, so here we go: */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        return 2;
-    }
-
-
-    /* make sure outfile is (re)opened in BINARY mode */
-
-    png_init_io(png_ptr, mainprog_ptr->outfile);
-
-
-    /* set the compression levels--in general, always want to leave filtering
-     * turned on (except for palette images) and allow all of the filters,
-     * which is the default; want 32K zlib window, unless entire image buffer
-     * is 16K or smaller (unknown here)--also the default; usually want max
-     * compression (NOT the default); and remaining compression flags should
-     * be left alone */
-
-    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
-/*
-    >> this is default for no filtering; Z_FILTERED is default otherwise:
-    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
-    >> these are all defaults:
-    png_set_compression_mem_level(png_ptr, 8);
-    png_set_compression_window_bits(png_ptr, 15);
-    png_set_compression_method(png_ptr, 8);
- */
-
-
-    /* set the image parameters appropriately */
-
-    if (mainprog_ptr->pnmtype == 5)
-        color_type = PNG_COLOR_TYPE_GRAY;
-    else if (mainprog_ptr->pnmtype == 6)
-        color_type = PNG_COLOR_TYPE_RGB;
-    else if (mainprog_ptr->pnmtype == 8)
-        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-    else {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        return 11;
-    }
-
-    interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
-                                               PNG_INTERLACE_NONE;
-
-    png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
-      mainprog_ptr->sample_depth, color_type, interlace_type,
-      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
-
-    if (mainprog_ptr->gamma > 0.0)
-        png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
-
-    if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
-        png_color_16  background;
-
-        background.red = mainprog_ptr->bg_red;
-        background.green = mainprog_ptr->bg_green;
-        background.blue = mainprog_ptr->bg_blue;
-        png_set_bKGD(png_ptr, info_ptr, &background);
-    }
-
-    if (mainprog_ptr->have_time) {
-        png_time  modtime;
-
-        png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
-        png_set_tIME(png_ptr, info_ptr, &modtime);
-    }
-
-    if (mainprog_ptr->have_text) {
-        png_text  text[6];
-        int  num_text = 0;
-
-        if (mainprog_ptr->have_text & TEXT_TITLE) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Title";
-            text[num_text].text = mainprog_ptr->title;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_AUTHOR) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Author";
-            text[num_text].text = mainprog_ptr->author;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_DESC) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Description";
-            text[num_text].text = mainprog_ptr->desc;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_COPY) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "Copyright";
-            text[num_text].text = mainprog_ptr->copyright;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_EMAIL) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "E-mail";
-            text[num_text].text = mainprog_ptr->email;
-            ++num_text;
-        }
-        if (mainprog_ptr->have_text & TEXT_URL) {
-            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
-            text[num_text].key = "URL";
-            text[num_text].text = mainprog_ptr->url;
-            ++num_text;
-        }
-        png_set_text(png_ptr, info_ptr, text, num_text);
-    }
-
-
-    /* write all chunks up to (but not including) first IDAT */
-
-    png_write_info(png_ptr, info_ptr);
-
-
-    /* if we wanted to write any more text info *after* the image data, we
-     * would set up text struct(s) here and call png_set_text() again, with
-     * just the new data; png_set_tIME() could also go here, but it would
-     * have no effect since we already called it above (only one tIME chunk
-     * allowed) */
-
-
-    /* set up the transformations:  for now, just pack low-bit-depth pixels
-     * into bytes (one, two or four pixels per byte) */
-
-    png_set_packing(png_ptr);
-/*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
-
-
-    /* make sure we save our pointers for use in writepng_encode_image() */
-
-    mainprog_ptr->png_ptr = png_ptr;
-    mainprog_ptr->info_ptr = info_ptr;
-
-
-    /* OK, that's all we need to do for now; return happy */
-
-    return 0;
-}
-
-
-
-
-
-/* returns 0 for success, 2 for libpng (longjmp) problem */
-
-int writepng_encode_image(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* as always, setjmp() must be called in every function that calls a
-     * PNG-writing libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* and now we just write the whole image; libpng takes care of interlacing
-     * for us */
-
-    png_write_image(png_ptr, mainprog_ptr->row_pointers);
-
-
-    /* since that's it, we also close out the end of the PNG file now--if we
-     * had any text or time info to write after the IDATs, second argument
-     * would be info_ptr, but we optimize slightly by sending NULL pointer: */
-
-    png_write_end(png_ptr, NULL);
-
-    return 0;
-}
-
-
-
-
-
-/* returns 0 if succeeds, 2 if libpng problem */
-
-int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* as always, setjmp() must be called in every function that calls a
-     * PNG-writing libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* image_data points at our one row of image data */
-
-    png_write_row(png_ptr, mainprog_ptr->image_data);
-
-    return 0;
-}
-
-
-
-
-
-/* returns 0 if succeeds, 2 if libpng problem */
-
-int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* as always, setjmp() must be called in every function that calls a
-     * PNG-writing libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* close out PNG file; if we had any text or time info to write after
-     * the IDATs, second argument would be info_ptr: */
-
-    png_write_end(png_ptr, NULL);
-
-    return 0;
-}
-
-
-
-
-
-void writepng_cleanup(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-    if (png_ptr && info_ptr)
-        png_destroy_write_struct(&png_ptr, &info_ptr);
-}
-
-
-
-
-
-static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
-{
-    mainprog_info  *mainprog_ptr;
-
-    /* This function, aside from the extra step of retrieving the "error
-     * pointer" (below) and the fact that it exists within the application
-     * rather than within libpng, is essentially identical to libpng's
-     * default error handler.  The second point is critical:  since both
-     * setjmp() and longjmp() are called from the same code, they are
-     * guaranteed to have compatible notions of how big a jmp_buf is,
-     * regardless of whether _BSD_SOURCE or anything else has (or has not)
-     * been defined. */
-
-    fprintf(stderr, "writepng libpng error: %s\n", msg);
-    fflush(stderr);
-
-    mainprog_ptr = png_get_error_ptr(png_ptr);
-    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
-        fprintf(stderr,
-          "writepng severe error:  jmpbuf not recoverable; terminating.\n");
-        fflush(stderr);
-        exit(99);
-    }
-
-    longjmp(mainprog_ptr->jmpbuf, 1);
-}
diff --git a/contrib/gregbook/writepng.h b/contrib/gregbook/writepng.h
deleted file mode 100644
index 78b966b..0000000
--- a/contrib/gregbook/writepng.h
+++ /dev/null
@@ -1,133 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   wpng - simple PNG-writing program                             writepng.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-#define TEXT_TITLE    0x01
-#define TEXT_AUTHOR   0x02
-#define TEXT_DESC     0x04
-#define TEXT_COPY     0x08
-#define TEXT_EMAIL    0x10
-#define TEXT_URL      0x20
-
-#define TEXT_TITLE_OFFSET        0
-#define TEXT_AUTHOR_OFFSET      72
-#define TEXT_COPY_OFFSET     (2*72)
-#define TEXT_EMAIL_OFFSET    (3*72)
-#define TEXT_URL_OFFSET      (4*72)
-#define TEXT_DESC_OFFSET     (5*72)
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-typedef struct _mainprog_info {
-    double gamma;
-    long width;
-    long height;
-    time_t modtime;
-    FILE *infile;
-    FILE *outfile;
-    void *png_ptr;
-    void *info_ptr;
-    uch *image_data;
-    uch **row_pointers;
-    char *title;
-    char *author;
-    char *desc;
-    char *copyright;
-    char *email;
-    char *url;
-    int filter;    /* command-line-filter flag, not PNG row filter! */
-    int pnmtype;
-    int sample_depth;
-    int interlaced;
-    int have_bg;
-    int have_time;
-    int have_text;
-    jmp_buf jmpbuf;
-    uch bg_red;
-    uch bg_green;
-    uch bg_blue;
-} mainprog_info;
-
-
-/* prototypes for public functions in writepng.c */
-
-void writepng_version_info(void);
-
-int writepng_init(mainprog_info *mainprog_ptr);
-
-int writepng_encode_image(mainprog_info *mainprog_ptr);
-
-int writepng_encode_row(mainprog_info *mainprog_ptr);
-
-int writepng_encode_finish(mainprog_info *mainprog_ptr);
-
-void writepng_cleanup(mainprog_info *mainprog_ptr);