diff options
author | Patrick Scott <phanna@android.com> | 2009-07-22 11:50:02 -0400 |
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committer | Patrick Scott <phanna@android.com> | 2009-07-22 11:51:29 -0400 |
commit | a0bb96c34e65378853ee518bac502842d26c2d1a (patch) | |
tree | e5a1a570c92e2ef58a0d96cd3dfefbab796fb37e /pngrtran.c | |
parent | 4215dd1533c56e1a89ae6f1d6ea68677fac27fda (diff) | |
download | external_libpng-a0bb96c34e65378853ee518bac502842d26c2d1a.zip external_libpng-a0bb96c34e65378853ee518bac502842d26c2d1a.tar.gz external_libpng-a0bb96c34e65378853ee518bac502842d26c2d1a.tar.bz2 |
Update libpng to 1.2.38 to patch a minor security issue.
Diffstat (limited to 'pngrtran.c')
-rw-r--r-- | pngrtran.c | 408 |
1 files changed, 244 insertions, 164 deletions
@@ -1,12 +1,15 @@ /* pngrtran.c - transforms the data in a row for PNG readers * - * Last changed in libpng 1.2.35 [February 14, 2009] - * For conditions of distribution and use, see copyright notice in png.h + * Last changed in libpng 1.2.38 [July 16, 2009] * Copyright (c) 1998-2009 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * * This file contains functions optionally called by an application * in order to tell libpng how to handle data when reading a PNG. * Transformations that are used in both reading and writing are @@ -23,24 +26,29 @@ png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) { png_debug(1, "in png_set_crc_action"); /* Tell libpng how we react to CRC errors in critical chunks */ - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; switch (crit_action) { - case PNG_CRC_NO_CHANGE: /* leave setting as is */ + case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; - case PNG_CRC_WARN_USE: /* warn/use data */ + + case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE; break; - case PNG_CRC_QUIET_USE: /* quiet/use data */ + + case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE | PNG_FLAG_CRC_CRITICAL_IGNORE; break; - case PNG_CRC_WARN_DISCARD: /* not a valid action for critical data */ + + case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */ png_warning(png_ptr, "Can't discard critical data on CRC error."); - case PNG_CRC_ERROR_QUIT: /* error/quit */ + case PNG_CRC_ERROR_QUIT: /* Error/quit */ + case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; @@ -49,22 +57,27 @@ png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) switch (ancil_action) { - case PNG_CRC_NO_CHANGE: /* leave setting as is */ + case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; - case PNG_CRC_WARN_USE: /* warn/use data */ + + case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE; break; - case PNG_CRC_QUIET_USE: /* quiet/use data */ + + case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN; break; - case PNG_CRC_ERROR_QUIT: /* error/quit */ + + case PNG_CRC_ERROR_QUIT: /* Error/quit */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN; break; - case PNG_CRC_WARN_DISCARD: /* warn/discard data */ + + case PNG_CRC_WARN_DISCARD: /* Warn/discard data */ + case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; @@ -74,14 +87,15 @@ png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action) #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ defined(PNG_FLOATING_POINT_SUPPORTED) -/* handle alpha and tRNS via a background color */ +/* Handle alpha and tRNS via a background color */ void PNGAPI png_set_background(png_structp png_ptr, png_color_16p background_color, int background_gamma_code, int need_expand, double background_gamma) { png_debug(1, "in png_set_background"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN) { png_warning(png_ptr, "Application must supply a known background gamma"); @@ -98,12 +112,13 @@ png_set_background(png_structp png_ptr, #endif #if defined(PNG_READ_16_TO_8_SUPPORTED) -/* strip 16 bit depth files to 8 bit depth */ +/* Strip 16 bit depth files to 8 bit depth */ void PNGAPI png_set_strip_16(png_structp png_ptr) { png_debug(1, "in png_set_strip_16"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->transformations |= PNG_16_TO_8; } #endif @@ -113,7 +128,8 @@ void PNGAPI png_set_strip_alpha(png_structp png_ptr) { png_debug(1, "in png_set_strip_alpha"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->flags |= PNG_FLAG_STRIP_ALPHA; } #endif @@ -143,7 +159,8 @@ png_set_dither(png_structp png_ptr, png_colorp palette, int full_dither) { png_debug(1, "in png_set_dither"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->transformations |= PNG_DITHER; if (!full_dither) @@ -161,27 +178,29 @@ png_set_dither(png_structp png_ptr, png_colorp palette, if (histogram != NULL) { /* This is easy enough, just throw out the least used colors. - Perhaps not the best solution, but good enough. */ + * Perhaps not the best solution, but good enough. + */ int i; - /* initialize an array to sort colors */ + /* Initialize an array to sort colors */ png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); - /* initialize the dither_sort array */ + /* Initialize the dither_sort array */ for (i = 0; i < num_palette; i++) png_ptr->dither_sort[i] = (png_byte)i; /* Find the least used palette entries by starting a - bubble sort, and running it until we have sorted - out enough colors. Note that we don't care about - sorting all the colors, just finding which are - least used. */ + * bubble sort, and running it until we have sorted + * out enough colors. Note that we don't care about + * sorting all the colors, just finding which are + * least used. + */ for (i = num_palette - 1; i >= maximum_colors; i--) { - int done; /* to stop early if the list is pre-sorted */ + int done; /* To stop early if the list is pre-sorted */ int j; done = 1; @@ -202,13 +221,14 @@ png_set_dither(png_structp png_ptr, png_colorp palette, break; } - /* swap the palette around, and set up a table, if necessary */ + /* Swap the palette around, and set up a table, if necessary */ if (full_dither) { int j = num_palette; - /* put all the useful colors within the max, but don't - move the others */ + /* Put all the useful colors within the max, but don't + * move the others. + */ for (i = 0; i < maximum_colors; i++) { if ((int)png_ptr->dither_sort[i] >= maximum_colors) @@ -224,11 +244,12 @@ png_set_dither(png_structp png_ptr, png_colorp palette, { int j = num_palette; - /* move all the used colors inside the max limit, and - develop a translation table */ + /* Move all the used colors inside the max limit, and + * develop a translation table. + */ for (i = 0; i < maximum_colors; i++) { - /* only move the colors we need to */ + /* Only move the colors we need to */ if ((int)png_ptr->dither_sort[i] >= maximum_colors) { png_color tmp_color; @@ -240,20 +261,20 @@ png_set_dither(png_structp png_ptr, png_colorp palette, tmp_color = palette[j]; palette[j] = palette[i]; palette[i] = tmp_color; - /* indicate where the color went */ + /* Indicate where the color went */ png_ptr->dither_index[j] = (png_byte)i; png_ptr->dither_index[i] = (png_byte)j; } } - /* find closest color for those colors we are not using */ + /* Find closest color for those colors we are not using */ for (i = 0; i < num_palette; i++) { if ((int)png_ptr->dither_index[i] >= maximum_colors) { int min_d, k, min_k, d_index; - /* find the closest color to one we threw out */ + /* Find the closest color to one we threw out */ d_index = png_ptr->dither_index[i]; min_d = PNG_COLOR_DIST(palette[d_index], palette[0]); for (k = 1, min_k = 0; k < maximum_colors; k++) @@ -268,7 +289,7 @@ png_set_dither(png_structp png_ptr, png_colorp palette, min_k = k; } } - /* point to closest color */ + /* Point to closest color */ png_ptr->dither_index[i] = (png_byte)min_k; } } @@ -279,13 +300,13 @@ png_set_dither(png_structp png_ptr, png_colorp palette, else { /* This is much harder to do simply (and quickly). Perhaps - we need to go through a median cut routine, but those - don't always behave themselves with only a few colors - as input. So we will just find the closest two colors, - and throw out one of them (chosen somewhat randomly). - [We don't understand this at all, so if someone wants to - work on improving it, be our guest - AED, GRP] - */ + * we need to go through a median cut routine, but those + * don't always behave themselves with only a few colors + * as input. So we will just find the closest two colors, + * and throw out one of them (chosen somewhat randomly). + * [We don't understand this at all, so if someone wants to + * work on improving it, be our guest - AED, GRP] + */ int i; int max_d; int num_new_palette; @@ -294,13 +315,13 @@ png_set_dither(png_structp png_ptr, png_colorp palette, t = NULL; - /* initialize palette index arrays */ + /* Initialize palette index arrays */ png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette * png_sizeof(png_byte))); - /* initialize the sort array */ + /* Initialize the sort array */ for (i = 0; i < num_palette; i++) { png_ptr->index_to_palette[i] = (png_byte)i; @@ -313,14 +334,14 @@ png_set_dither(png_structp png_ptr, png_colorp palette, num_new_palette = num_palette; - /* initial wild guess at how far apart the farthest pixel - pair we will be eliminating will be. Larger - numbers mean more areas will be allocated, Smaller - numbers run the risk of not saving enough data, and - having to do this all over again. - - I have not done extensive checking on this number. - */ + /* Initial wild guess at how far apart the farthest pixel + * pair we will be eliminating will be. Larger + * numbers mean more areas will be allocated, Smaller + * numbers run the risk of not saving enough data, and + * having to do this all over again. + * + * I have not done extensive checking on this number. + */ max_d = 96; while (num_new_palette > maximum_colors) @@ -455,10 +476,8 @@ png_set_dither(png_structp png_ptr, png_colorp palette, int num_green = (1 << PNG_DITHER_GREEN_BITS); int num_blue = (1 << PNG_DITHER_BLUE_BITS); png_size_t num_entries = ((png_size_t)1 << total_bits); - png_ptr->palette_lookup = (png_bytep )png_malloc(png_ptr, (png_uint_32)(num_entries * png_sizeof(png_byte))); - png_memset(png_ptr->palette_lookup, 0, num_entries * png_sizeof(png_byte)); @@ -525,7 +544,8 @@ void PNGAPI png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma) { png_debug(1, "in png_set_gamma"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) || (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) || (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) @@ -544,7 +564,8 @@ void PNGAPI png_set_expand(png_structp png_ptr) { png_debug(1, "in png_set_expand"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } @@ -571,7 +592,8 @@ void PNGAPI png_set_palette_to_rgb(png_structp png_ptr) { png_debug(1, "in png_set_palette_to_rgb"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } @@ -582,7 +604,8 @@ void PNGAPI png_set_expand_gray_1_2_4_to_8(png_structp png_ptr) { png_debug(1, "in png_set_expand_gray_1_2_4_to_8"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->transformations |= PNG_EXPAND; png_ptr->flags &= ~PNG_FLAG_ROW_INIT; } @@ -595,7 +618,8 @@ void PNGAPI png_set_gray_1_2_4_to_8(png_structp png_ptr) { png_debug(1, "in png_set_gray_1_2_4_to_8"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); } #endif @@ -631,10 +655,11 @@ void PNGAPI png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red, double green) { - int red_fixed = (int)((float)red*100000.0 + 0.5); - int green_fixed = (int)((float)green*100000.0 + 0.5); - if (png_ptr == NULL) return; - png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed); + int red_fixed = (int)((float)red*100000.0 + 0.5); + int green_fixed = (int)((float)green*100000.0 + 0.5); + if (png_ptr == NULL) + return; + png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed); } #endif @@ -643,13 +668,16 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, png_fixed_point red, png_fixed_point green) { png_debug(1, "in png_set_rgb_to_gray"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; switch(error_action) { case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY; break; + case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; break; + case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; } if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) @@ -671,8 +699,8 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, } else if (red + green < 100000L) { - red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); - green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); + red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L); + green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L); } else { @@ -689,14 +717,15 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action, #endif #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ - defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \ - defined(PNG_LEGACY_SUPPORTED) + defined(PNG_LEGACY_SUPPORTED) || \ + defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) void PNGAPI png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr read_user_transform_fn) { png_debug(1, "in png_set_read_user_transform_fn"); - if (png_ptr == NULL) return; + if (png_ptr == NULL) + return; #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) png_ptr->transformations |= PNG_USER_TRANSFORM; png_ptr->read_user_transform_fn = read_user_transform_fn; @@ -729,8 +758,9 @@ png_init_read_transformations(png_structp png_ptr) #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) /* Detect gray background and attempt to enable optimization - * for gray --> RGB case */ - /* Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or + * for gray --> RGB case + * + * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or * RGB_ALPHA (in which case need_expand is superfluous anyway), the * background color might actually be gray yet not be flagged as such. * This is not a problem for the current code, which uses @@ -757,7 +787,7 @@ png_init_read_transformations(png_structp png_ptr) { if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */ { - /* expand background and tRNS chunks */ + /* Expand background and tRNS chunks */ switch (png_ptr->bit_depth) { case 1: @@ -771,6 +801,7 @@ png_init_read_transformations(png_structp png_ptr) = png_ptr->trans_values.blue = png_ptr->trans_values.gray; } break; + case 2: png_ptr->background.gray *= (png_uint_16)0x55; png_ptr->background.red = png_ptr->background.green @@ -782,6 +813,7 @@ png_init_read_transformations(png_structp png_ptr) = png_ptr->trans_values.blue = png_ptr->trans_values.gray; } break; + case 4: png_ptr->background.gray *= (png_uint_16)0x11; png_ptr->background.red = png_ptr->background.green @@ -793,7 +825,9 @@ png_init_read_transformations(png_structp png_ptr) = png_ptr->trans_values.blue = png_ptr->trans_values.gray; } break; + case 8: + case 16: png_ptr->background.red = png_ptr->background.green = png_ptr->background.blue = png_ptr->background.gray; @@ -816,8 +850,9 @@ png_init_read_transformations(png_structp png_ptr) if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) #endif { - /* invert the alpha channel (in tRNS) unless the pixels are - going to be expanded, in which case leave it for later */ + /* Invert the alpha channel (in tRNS) unless the pixels are + * going to be expanded, in which case leave it for later + */ int i, istop; istop=(int)png_ptr->num_trans; for (i=0; i<istop; i++) @@ -844,7 +879,7 @@ png_init_read_transformations(png_structp png_ptr) for (i=0; i<png_ptr->num_trans; i++) { if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff) - k=1; /* partial transparency is present */ + k=1; /* Partial transparency is present */ } if (k == 0) png_ptr->transformations &= ~PNG_GAMMA; @@ -859,8 +894,7 @@ png_init_read_transformations(png_structp png_ptr) { if (color_type == PNG_COLOR_TYPE_PALETTE) { - /* could skip if no transparency and - */ + /* Could skip if no transparency */ png_color back, back_1; png_colorp palette = png_ptr->palette; int num_palette = png_ptr->num_palette; @@ -885,10 +919,12 @@ png_init_read_transformations(png_structp png_ptr) g = (png_ptr->screen_gamma); gs = 1.0; break; + case PNG_BACKGROUND_GAMMA_FILE: g = 1.0 / (png_ptr->gamma); gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); break; + case PNG_BACKGROUND_GAMMA_UNIQUE: g = 1.0 / (png_ptr->background_gamma); gs = 1.0 / (png_ptr->background_gamma * @@ -977,10 +1013,12 @@ png_init_read_transformations(png_structp png_ptr) g = (png_ptr->screen_gamma); gs = 1.0; break; + case PNG_BACKGROUND_GAMMA_FILE: g = 1.0 / (png_ptr->gamma); gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); break; + case PNG_BACKGROUND_GAMMA_UNIQUE: g = 1.0 / (png_ptr->background_gamma); gs = 1.0 / (png_ptr->background_gamma * @@ -1022,7 +1060,7 @@ png_init_read_transformations(png_structp png_ptr) } } else - /* transformation does not include PNG_BACKGROUND */ + /* Transformation does not include PNG_BACKGROUND */ #endif /* PNG_READ_BACKGROUND_SUPPORTED */ if (color_type == PNG_COLOR_TYPE_PALETTE) { @@ -1142,10 +1180,6 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) { if (png_ptr->transformations & PNG_EXPAND_tRNS) info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; -#if 0 /* Removed from libpng-1.2.27 */ - else - info_ptr->color_type |= PNG_COLOR_MASK_COLOR; -#endif } if (info_ptr->bit_depth < 8) info_ptr->bit_depth = 8; @@ -1194,8 +1228,8 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) if (png_ptr->transformations & PNG_DITHER) { if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || - (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && - png_ptr->palette_lookup && info_ptr->bit_depth == 8) + (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && + png_ptr->palette_lookup && info_ptr->bit_depth == 8) { info_ptr->color_type = PNG_COLOR_TYPE_PALETTE; } @@ -1229,7 +1263,7 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr) (info_ptr->color_type == PNG_COLOR_TYPE_GRAY))) { info_ptr->channels++; - /* if adding a true alpha channel not just filler */ + /* If adding a true alpha channel not just filler */ #if !defined(PNG_1_0_X) if (png_ptr->transformations & PNG_ADD_ALPHA) info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; @@ -1284,7 +1318,8 @@ png_do_read_transformations(png_structp png_ptr) if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) /* Application has failed to call either png_read_start_image() * or png_read_update_info() after setting transforms that expand - * pixels. This check added to libpng-1.2.19 */ + * pixels. This check added to libpng-1.2.19 + */ #if (PNG_WARN_UNINITIALIZED_ROW==1) png_error(png_ptr, "Uninitialized row"); #else @@ -1337,39 +1372,41 @@ png_do_read_transformations(png_structp png_ptr) } #endif -/* -From Andreas Dilger e-mail to png-implement, 26 March 1998: - - In most cases, the "simple transparency" should be done prior to doing - gray-to-RGB, or you will have to test 3x as many bytes to check if a - pixel is transparent. You would also need to make sure that the - transparency information is upgraded to RGB. - - To summarize, the current flow is: - - Gray + simple transparency -> compare 1 or 2 gray bytes and composite - with background "in place" if transparent, - convert to RGB if necessary - - Gray + alpha -> composite with gray background and remove alpha bytes, - convert to RGB if necessary - - To support RGB backgrounds for gray images we need: - - Gray + simple transparency -> convert to RGB + simple transparency, compare - 3 or 6 bytes and composite with background - "in place" if transparent (3x compare/pixel - compared to doing composite with gray bkgrnd) - - Gray + alpha -> convert to RGB + alpha, composite with background and - remove alpha bytes (3x float operations/pixel - compared with composite on gray background) - - Greg's change will do this. The reason it wasn't done before is for - performance, as this increases the per-pixel operations. If we would check - in advance if the background was gray or RGB, and position the gray-to-RGB - transform appropriately, then it would save a lot of work/time. +/* From Andreas Dilger e-mail to png-implement, 26 March 1998: + * + * In most cases, the "simple transparency" should be done prior to doing + * gray-to-RGB, or you will have to test 3x as many bytes to check if a + * pixel is transparent. You would also need to make sure that the + * transparency information is upgraded to RGB. + * + * To summarize, the current flow is: + * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite + * with background "in place" if transparent, + * convert to RGB if necessary + * - Gray + alpha -> composite with gray background and remove alpha bytes, + * convert to RGB if necessary + * + * To support RGB backgrounds for gray images we need: + * - Gray + simple transparency -> convert to RGB + simple transparency, + * compare 3 or 6 bytes and composite with + * background "in place" if transparent + * (3x compare/pixel compared to doing + * composite with gray bkgrnd) + * - Gray + alpha -> convert to RGB + alpha, composite with background and + * remove alpha bytes (3x float + * operations/pixel compared with composite + * on gray background) + * + * Greg's change will do this. The reason it wasn't done before is for + * performance, as this increases the per-pixel operations. If we would check + * in advance if the background was gray or RGB, and position the gray-to-RGB + * transform appropriately, then it would save a lot of work/time. */ #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) - /* if gray -> RGB, do so now only if background is non-gray; else do later - * for performance reasons */ + /* If gray -> RGB, do so now only if background is non-gray; else do later + * for performance reasons + */ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); @@ -1394,14 +1431,14 @@ From Andreas Dilger e-mail to png-implement, 26 March 1998: #if defined(PNG_READ_GAMMA_SUPPORTED) if ((png_ptr->transformations & PNG_GAMMA) && #if defined(PNG_READ_BACKGROUND_SUPPORTED) - !((png_ptr->transformations & PNG_BACKGROUND) && - ((png_ptr->num_trans != 0) || - (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && + !((png_ptr->transformations & PNG_BACKGROUND) && + ((png_ptr->num_trans != 0) || + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && #endif - (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) + (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1, - png_ptr->gamma_table, png_ptr->gamma_16_table, - png_ptr->gamma_shift); + png_ptr->gamma_table, png_ptr->gamma_16_table, + png_ptr->gamma_shift); #endif #if defined(PNG_READ_16_TO_8_SUPPORTED) @@ -1446,7 +1483,7 @@ From Andreas Dilger e-mail to png-implement, 26 March 1998: #endif #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) - /* if gray -> RGB, do so now only if we did not do so above */ + /* If gray -> RGB, do so now only if we did not do so above */ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1); @@ -1477,16 +1514,16 @@ From Andreas Dilger e-mail to png-implement, 26 March 1998: if (png_ptr->transformations & PNG_USER_TRANSFORM) { if (png_ptr->read_user_transform_fn != NULL) - (*(png_ptr->read_user_transform_fn)) /* user read transform function */ - (png_ptr, /* png_ptr */ - &(png_ptr->row_info), /* row_info: */ - /* png_uint_32 width; width of row */ - /* png_uint_32 rowbytes; number of bytes in row */ - /* png_byte color_type; color type of pixels */ - /* png_byte bit_depth; bit depth of samples */ - /* png_byte channels; number of channels (1-4) */ - /* png_byte pixel_depth; bits per pixel (depth*channels) */ - png_ptr->row_buf + 1); /* start of pixel data for row */ + (*(png_ptr->read_user_transform_fn)) /* User read transform function */ + (png_ptr, /* png_ptr */ + &(png_ptr->row_info), /* row_info: */ + /* png_uint_32 width; width of row */ + /* png_uint_32 rowbytes; number of bytes in row */ + /* png_byte color_type; color type of pixels */ + /* png_byte bit_depth; bit depth of samples */ + /* png_byte channels; number of channels (1-4) */ + /* png_byte pixel_depth; bits per pixel (depth*channels) */ + png_ptr->row_buf + 1); /* start of pixel data for row */ #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) if (png_ptr->user_transform_depth) png_ptr->row_info.bit_depth = png_ptr->user_transform_depth; @@ -1544,6 +1581,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row) } break; } + case 2: { @@ -1565,6 +1603,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row) } break; } + case 4: { png_bytep sp = row + (png_size_t)((row_width - 1) >> 1); @@ -1656,6 +1695,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) } break; } + case 4: { png_bytep bp = row; @@ -1671,6 +1711,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) } break; } + case 8: { png_bytep bp = row; @@ -1683,6 +1724,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) } break; } + case 16: { png_bytep bp = row; @@ -1704,7 +1746,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits) #endif #if defined(PNG_READ_16_TO_8_SUPPORTED) -/* chop rows of bit depth 16 down to 8 */ +/* Chop rows of bit depth 16 down to 8 */ void /* PRIVATE */ png_do_chop(png_row_infop row_info, png_bytep row) { @@ -1728,14 +1770,17 @@ png_do_chop(png_row_infop row_info, png_bytep row) * * What the ideal calculation should be: * *dp = (((((png_uint_32)(*sp) << 8) | - * (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L; + * (png_uint_32)(*(sp + 1))) * 255 + 127) + * / (png_uint_32)65535L; * * GRR: no, I think this is what it really should be: * *dp = (((((png_uint_32)(*sp) << 8) | - * (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L; + * (png_uint_32)(*(sp + 1))) + 128L) + * / (png_uint_32)257L; * * GRR: here's the exact calculation with shifts: - * temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L; + * temp = (((png_uint_32)(*sp) << 8) | + * (png_uint_32)(*(sp + 1))) + 128L; * *dp = (temp - (temp >> 8)) >> 8; * * Approximate calculation with shift/add instead of multiply/divide: @@ -2125,7 +2170,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row, #endif #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED) -/* expand grayscale files to RGB, with or without alpha */ +/* Expand grayscale files to RGB, with or without alpha */ void /* PRIVATE */ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) { @@ -2208,7 +2253,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) #endif #if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) -/* reduce RGB files to grayscale, with or without alpha +/* Reduce RGB files to grayscale, with or without alpha * using the equation given in Poynton's ColorFAQ at * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008) * New link: @@ -2486,18 +2531,22 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette) num_palette = 2; color_inc = 0xff; break; + case 2: num_palette = 4; color_inc = 0x55; break; + case 4: num_palette = 16; color_inc = 0x11; break; + case 8: num_palette = 256; color_inc = 1; break; + default: num_palette = 0; color_inc = 0; @@ -2675,7 +2724,7 @@ png_correct_palette(png_structp png_ptr, png_colorp palette, } } } - else /* assume grayscale palette (what else could it be?) */ + else /* Assume grayscale palette (what else could it be?) */ { int i; @@ -2751,6 +2800,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case 2: { #if defined(PNG_READ_GAMMA_SUPPORTED) @@ -2807,6 +2857,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case 4: { #if defined(PNG_READ_GAMMA_SUPPORTED) @@ -2863,6 +2914,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case 8: { #if defined(PNG_READ_GAMMA_SUPPORTED) @@ -2895,6 +2947,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case 16: { #if defined(PNG_READ_GAMMA_SUPPORTED) @@ -2908,7 +2961,7 @@ png_do_background(png_row_infop row_info, png_bytep row, v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); if (v == trans_values->gray) { - /* background is already in screen gamma */ + /* Background is already in screen gamma */ *sp = (png_byte)((background->gray >> 8) & 0xff); *(sp + 1) = (png_byte)(background->gray & 0xff); } @@ -2941,6 +2994,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_RGB: { if (row_info->bit_depth == 8) @@ -2998,7 +3052,7 @@ png_do_background(png_row_infop row_info, png_bytep row, if (r == trans_values->red && g == trans_values->green && b == trans_values->blue) { - /* background is already in screen gamma */ + /* Background is already in screen gamma */ *sp = (png_byte)((background->red >> 8) & 0xff); *(sp + 1) = (png_byte)(background->red & 0xff); *(sp + 2) = (png_byte)((background->green >> 8) & 0xff); @@ -3045,6 +3099,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_GRAY_ALPHA: { if (row_info->bit_depth == 8) @@ -3065,7 +3120,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } else if (a == 0) { - /* background is already in screen gamma */ + /* Background is already in screen gamma */ *dp = (png_byte)background->gray; } else @@ -3132,7 +3187,7 @@ png_do_background(png_row_infop row_info, png_bytep row, else #endif { - /* background is already in screen gamma */ + /* Background is already in screen gamma */ *dp = (png_byte)((background->gray >> 8) & 0xff); *(dp + 1) = (png_byte)(background->gray & 0xff); } @@ -3187,6 +3242,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_RGB_ALPHA: { if (row_info->bit_depth == 8) @@ -3209,7 +3265,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } else if (a == 0) { - /* background is already in screen gamma */ + /* Background is already in screen gamma */ *dp = (png_byte)background->red; *(dp + 1) = (png_byte)background->green; *(dp + 2) = (png_byte)background->blue; @@ -3290,7 +3346,7 @@ png_do_background(png_row_infop row_info, png_bytep row, } else if (a == 0) { - /* background is already in screen gamma */ + /* Background is already in screen gamma */ *dp = (png_byte)((background->red >> 8) & 0xff); *(dp + 1) = (png_byte)(background->red & 0xff); *(dp + 2) = (png_byte)((background->green >> 8) & 0xff); @@ -3445,6 +3501,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_RGB_ALPHA: { if (row_info->bit_depth == 8) @@ -3482,6 +3539,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_GRAY_ALPHA: { if (row_info->bit_depth == 8) @@ -3506,6 +3564,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, } break; } + case PNG_COLOR_TYPE_GRAY: { if (row_info->bit_depth == 2) @@ -3526,6 +3585,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp++; } } + if (row_info->bit_depth == 4) { sp = row; @@ -3539,6 +3599,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp++; } } + else if (row_info->bit_depth == 8) { sp = row; @@ -3548,6 +3609,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row, sp++; } } + else if (row_info->bit_depth == 16) { sp = row; @@ -3613,6 +3675,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, } break; } + case 2: { sp = row + (png_size_t)((row_width - 1) >> 2); @@ -3634,6 +3697,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, } break; } + case 4: { sp = row + (png_size_t)((row_width - 1) >> 1); @@ -3698,6 +3762,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row, *dp-- = palette[*sp].red; sp--; } + row_info->bit_depth = 8; row_info->pixel_depth = 24; row_info->rowbytes = row_width * 3; @@ -3759,6 +3824,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, } break; } + case 2: { gray = (png_uint_16)((gray&0x03)*0x55); @@ -3782,6 +3848,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, } break; } + case 4: { gray = (png_uint_16)((gray&0x0f)*0x11); @@ -3805,6 +3872,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, break; } } + row_info->bit_depth = 8; row_info->pixel_depth = 8; row_info->rowbytes = row_width; @@ -3826,6 +3894,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, *dp-- = *sp--; } } + else if (row_info->bit_depth == 16) { png_byte gray_high = (gray >> 8) & 0xff; @@ -3848,6 +3917,7 @@ png_do_expand(png_row_infop row_info, png_bytep row, *dp-- = *sp--; } } + row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA; row_info->channels = 2; row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1); @@ -3945,13 +4015,13 @@ png_do_dither(png_row_infop row_info, png_bytep row, g = *sp++; b = *sp++; - /* this looks real messy, but the compiler will reduce - it down to a reasonable formula. For example, with - 5 bits per color, we get: - p = (((r >> 3) & 0x1f) << 10) | - (((g >> 3) & 0x1f) << 5) | - ((b >> 3) & 0x1f); - */ + /* This looks real messy, but the compiler will reduce + * it down to a reasonable formula. For example, with + * 5 bits per color, we get: + * p = (((r >> 3) & 0x1f) << 10) | + * (((g >> 3) & 0x1f) << 5) | + * ((b >> 3) & 0x1f); + */ p = (((r >> (8 - PNG_DITHER_RED_BITS)) & ((1 << PNG_DITHER_RED_BITS) - 1)) << (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) | @@ -4032,6 +4102,7 @@ png_build_gamma_table(png_structp png_ptr) if (png_ptr->screen_gamma > .000001) g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma); + else g = 1.0; @@ -4066,8 +4137,9 @@ png_build_gamma_table(png_structp png_ptr) if (png_ptr->screen_gamma > 0.000001) g = 1.0 / png_ptr->screen_gamma; + else - g = png_ptr->gamma; /* probably doing rgb_to_gray */ + g = png_ptr->gamma; /* Probably doing rgb_to_gray */ for (i = 0; i < 256; i++) { @@ -4088,8 +4160,10 @@ png_build_gamma_table(png_structp png_ptr) if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) { sig_bit = (int)png_ptr->sig_bit.red; + if ((int)png_ptr->sig_bit.green > sig_bit) sig_bit = png_ptr->sig_bit.green; + if ((int)png_ptr->sig_bit.blue > sig_bit) sig_bit = png_ptr->sig_bit.blue; } @@ -4100,6 +4174,7 @@ png_build_gamma_table(png_structp png_ptr) if (sig_bit > 0) shift = 16 - sig_bit; + else shift = 0; @@ -4111,6 +4186,7 @@ png_build_gamma_table(png_structp png_ptr) if (shift > 8) shift = 8; + if (shift < 0) shift = 0; @@ -4125,14 +4201,13 @@ png_build_gamma_table(png_structp png_ptr) png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr, (png_uint_32)(num * png_sizeof(png_uint_16p))); + png_memset(png_ptr->gamma_16_table, 0, num * png_sizeof(png_uint_16p)); if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND)) { double fin, fout; png_uint_32 last, max; - png_memset(png_ptr->gamma_16_table, 0, num * png_sizeof(png_uint_16p)); - for (i = 0; i < num; i++) { png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr, @@ -4169,6 +4244,7 @@ png_build_gamma_table(png_structp png_ptr) (png_uint_32)(256 * png_sizeof(png_uint_16))); ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4); + for (j = 0; j < 256; j++) { png_ptr->gamma_16_table[i][j] = @@ -4187,8 +4263,7 @@ png_build_gamma_table(png_structp png_ptr) png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr, (png_uint_32)(num * png_sizeof(png_uint_16p ))); - - png_memset(png_ptr->gamma_16_to_1, 0, num * png_sizeof(png_uint_16p)); + png_memset(png_ptr->gamma_16_to_1, 0, num * png_sizeof(png_uint_16p)); for (i = 0; i < num; i++) { @@ -4207,14 +4282,14 @@ png_build_gamma_table(png_structp png_ptr) if (png_ptr->screen_gamma > 0.000001) g = 1.0 / png_ptr->screen_gamma; + else - g = png_ptr->gamma; /* probably doing rgb_to_gray */ + g = png_ptr->gamma; /* Probably doing rgb_to_gray */ png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr, (png_uint_32)(num * png_sizeof(png_uint_16p))); - png_memset(png_ptr->gamma_16_from_1, 0, - num * png_sizeof(png_uint_16p)); + num * png_sizeof(png_uint_16p)); for (i = 0; i < num; i++) { @@ -4223,6 +4298,7 @@ png_build_gamma_table(png_structp png_ptr) ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4); + for (j = 0; j < 256; j++) { png_ptr->gamma_16_from_1[i][j] = @@ -4239,7 +4315,7 @@ png_build_gamma_table(png_structp png_ptr) #endif #if defined(PNG_MNG_FEATURES_SUPPORTED) -/* undoes intrapixel differencing */ +/* Undoes intrapixel differencing */ void /* PRIVATE */ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) { @@ -4259,8 +4335,10 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) if (row_info->color_type == PNG_COLOR_TYPE_RGB) bytes_per_pixel = 3; + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) bytes_per_pixel = 4; + else return; @@ -4277,8 +4355,10 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row) if (row_info->color_type == PNG_COLOR_TYPE_RGB) bytes_per_pixel = 6; + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) bytes_per_pixel = 8; + else return; |