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diff --git a/contrib/gregbook/README b/contrib/gregbook/README new file mode 100644 index 0000000..cb6e525 --- /dev/null +++ b/contrib/gregbook/README @@ -0,0 +1,186 @@ + =========================== + 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. |