Update libpng to 1.2.38 to patch a minor security issue.
diff --git a/pngrtran.c b/pngrtran.c
index a916f54..d7e6b4a 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -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_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 @@
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 @@
#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 @@
#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 @@
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 @@
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 @@
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 @@
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 @@
{
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 @@
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 @@
min_k = k;
}
}
- /* point to closest color */
+ /* Point to closest color */
png_ptr->dither_index[i] = (png_byte)min_k;
}
}
@@ -279,13 +300,13 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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_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 @@
}
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 @@
#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 @@
#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 @@
{
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_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_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_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 @@
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 @@
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 @@
{
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 @@
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 @@
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 @@
}
}
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 @@
{
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 @@
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 @@
(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 @@
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 @@
}
#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 @@
#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 @@
#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 @@
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 @@
}
break;
}
+
case 2:
{
@@ -1565,6 +1603,7 @@
}
break;
}
+
case 4:
{
png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
@@ -1656,6 +1695,7 @@
}
break;
}
+
case 4:
{
png_bytep bp = row;
@@ -1671,6 +1711,7 @@
}
break;
}
+
case 8:
{
png_bytep bp = row;
@@ -1683,6 +1724,7 @@
}
break;
}
+
case 16:
{
png_bytep bp = row;
@@ -1704,7 +1746,7 @@
#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 @@
*
* 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 @@
#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 @@
#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 @@
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 @@
}
}
}
- else /* assume grayscale palette (what else could it be?) */
+ else /* Assume grayscale palette (what else could it be?) */
{
int i;
@@ -2751,6 +2800,7 @@
}
break;
}
+
case 2:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2807,6 +2857,7 @@
}
break;
}
+
case 4:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2863,6 +2914,7 @@
}
break;
}
+
case 8:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2895,6 +2947,7 @@
}
break;
}
+
case 16:
{
#if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2908,7 +2961,7 @@
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 @@
}
break;
}
+
case PNG_COLOR_TYPE_RGB:
{
if (row_info->bit_depth == 8)
@@ -2998,7 +3052,7 @@
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 @@
}
break;
}
+
case PNG_COLOR_TYPE_GRAY_ALPHA:
{
if (row_info->bit_depth == 8)
@@ -3065,7 +3120,7 @@
}
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 @@
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 @@
}
break;
}
+
case PNG_COLOR_TYPE_RGB_ALPHA:
{
if (row_info->bit_depth == 8)
@@ -3209,7 +3265,7 @@
}
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 @@
}
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 @@
}
break;
}
+
case PNG_COLOR_TYPE_RGB_ALPHA:
{
if (row_info->bit_depth == 8)
@@ -3482,6 +3539,7 @@
}
break;
}
+
case PNG_COLOR_TYPE_GRAY_ALPHA:
{
if (row_info->bit_depth == 8)
@@ -3506,6 +3564,7 @@
}
break;
}
+
case PNG_COLOR_TYPE_GRAY:
{
if (row_info->bit_depth == 2)
@@ -3526,6 +3585,7 @@
sp++;
}
}
+
if (row_info->bit_depth == 4)
{
sp = row;
@@ -3539,6 +3599,7 @@
sp++;
}
}
+
else if (row_info->bit_depth == 8)
{
sp = row;
@@ -3548,6 +3609,7 @@
sp++;
}
}
+
else if (row_info->bit_depth == 16)
{
sp = row;
@@ -3613,6 +3675,7 @@
}
break;
}
+
case 2:
{
sp = row + (png_size_t)((row_width - 1) >> 2);
@@ -3634,6 +3697,7 @@
}
break;
}
+
case 4:
{
sp = row + (png_size_t)((row_width - 1) >> 1);
@@ -3698,6 +3762,7 @@
*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 @@
}
break;
}
+
case 2:
{
gray = (png_uint_16)((gray&0x03)*0x55);
@@ -3782,6 +3848,7 @@
}
break;
}
+
case 4:
{
gray = (png_uint_16)((gray&0x0f)*0x11);
@@ -3805,6 +3872,7 @@
break;
}
}
+
row_info->bit_depth = 8;
row_info->pixel_depth = 8;
row_info->rowbytes = row_width;
@@ -3826,6 +3894,7 @@
*dp-- = *sp--;
}
}
+
else if (row_info->bit_depth == 16)
{
png_byte gray_high = (gray >> 8) & 0xff;
@@ -3848,6 +3917,7 @@
*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 @@
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 @@
if (png_ptr->screen_gamma > .000001)
g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+
else
g = 1.0;
@@ -4066,8 +4137,9 @@
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 @@
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 @@
if (sig_bit > 0)
shift = 16 - sig_bit;
+
else
shift = 0;
@@ -4111,6 +4186,7 @@
if (shift > 8)
shift = 8;
+
if (shift < 0)
shift = 0;
@@ -4125,14 +4201,13 @@
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_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_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 @@
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 @@
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 @@
#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 @@
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 @@
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;