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[devel] Fixed a problem in png_do_expand_palette() exposed by optimization in

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1.5.3beta06
  Also removed a spurious (totally unused and confusing) member from png_info.
  The palette expand optimization prevented expansion to an intermediate RGBA
    form if tRNS was present but alpha was marked to be stripped; this exposed
    a check for tRNS in png_do_expand_palette() which is inconsistent with the
    code elsewhere in libpng.
This commit is contained in:
John Bowler 2011-06-14 23:01:07 -05:00 committed by Glenn Randers-Pehrson
parent 06a9684cfa
commit cd3b0cc4d9
4 changed files with 31 additions and 18 deletions
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11
ANNOUNCE
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@ -1,5 +1,5 @@
Libpng 1.5.4beta03 - June 14, 2011 Libpng 1.5.4beta03 - June 15, 2011
This is not intended to be a public release. It will be replaced This is not intended to be a public release. It will be replaced
within a few weeks by a public version or by another test version. within a few weeks by a public version or by another test version.
@ -202,7 +202,14 @@ Version 1.5.4beta02 [June 14, 2011]
called. called.
Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
Version 1.5.4beta03 [June 14, 2011] Version 1.5.4beta03 [June 15, 2011]
Fixed a problem in png_do_expand_palette() exposed by optimization in
1.5.3beta06
Also removed a spurious (totally unused and confusing) member from png_info.
The palette expand optimization prevented expansion to an intermediate RGBA
form if tRNS was present but alpha was marked to be stripped; this exposed
a check for tRNS in png_do_expand_palette() which is inconsistent with the
code elsewhere in libpng.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net: Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
(subscription required; visit (subscription required; visit

9
CHANGES
View File

@ -3465,7 +3465,14 @@ Version 1.5.4beta02 [June 14, 2011]
called. called.
Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
Version 1.5.4beta03 [June 14, 2011] Version 1.5.4beta03 [June 15, 2011]
Fixed a problem in png_do_expand_palette() exposed by optimization in
1.5.3beta06
Also removed a spurious (totally unused and confusing) member from png_info.
The palette expand optimization prevented expansion to an intermediate RGBA
form if tRNS was present but alpha was marked to be stripped; this exposed
a check for tRNS in png_do_expand_palette() which is inconsistent with the
code elsewhere in libpng.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit (subscription required; visit

1
pnginfo.h
View File

@ -138,7 +138,6 @@ defined(PNG_READ_BACKGROUND_SUPPORTED)
* single color specified that should be treated as fully transparent. * single color specified that should be treated as fully transparent.
* Data is valid if (valid & PNG_INFO_tRNS) is non-zero. * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
*/ */
png_bytep trans; /* alpha values for paletted image */
png_bytep trans_alpha; /* alpha values for paletted image */ png_bytep trans_alpha; /* alpha values for paletted image */
png_color_16 trans_color; /* transparent color for non-palette image */ png_color_16 trans_color; /* transparent color for non-palette image */
#endif #endif

28
pngrtran.c
View File

@ -4464,7 +4464,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
if (row_info->bit_depth == 8) if (row_info->bit_depth == 8)
{ {
{ {
if (trans_alpha != NULL) if (num_trans > 0)
{ {
sp = row + (png_size_t)row_width - 1; sp = row + (png_size_t)row_width - 1;
dp = row + (png_size_t)(row_width << 2) - 1; dp = row + (png_size_t)(row_width << 2) - 1;
@ -4518,7 +4518,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
*/ */
void /* PRIVATE */ void /* PRIVATE */
png_do_expand(png_row_infop row_info, png_bytep row, png_do_expand(png_row_infop row_info, png_bytep row,
png_const_color_16p trans_value) png_const_color_16p trans_color)
{ {
int shift, value; int shift, value;
png_bytep sp, dp; png_bytep sp, dp;
@ -4530,7 +4530,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
{ {
if (row_info->color_type == PNG_COLOR_TYPE_GRAY) if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
{ {
png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0); png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0);
if (row_info->bit_depth < 8) if (row_info->bit_depth < 8)
{ {
@ -4622,7 +4622,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
row_info->rowbytes = row_width; row_info->rowbytes = row_width;
} }
if (trans_value != NULL) if (trans_color != NULL)
{ {
if (row_info->bit_depth == 8) if (row_info->bit_depth == 8)
{ {
@ -4674,13 +4674,13 @@ png_do_expand(png_row_infop row_info, png_bytep row,
row_width); row_width);
} }
} }
else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value) else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
{ {
if (row_info->bit_depth == 8) if (row_info->bit_depth == 8)
{ {
png_byte red = (png_byte)(trans_value->red & 0xff); png_byte red = (png_byte)(trans_color->red & 0xff);
png_byte green = (png_byte)(trans_value->green & 0xff); png_byte green = (png_byte)(trans_color->green & 0xff);
png_byte blue = (png_byte)(trans_value->blue & 0xff); png_byte blue = (png_byte)(trans_color->blue & 0xff);
sp = row + (png_size_t)row_info->rowbytes - 1; sp = row + (png_size_t)row_info->rowbytes - 1;
dp = row + (png_size_t)(row_width << 2) - 1; dp = row + (png_size_t)(row_width << 2) - 1;
for (i = 0; i < row_width; i++) for (i = 0; i < row_width; i++)
@ -4698,12 +4698,12 @@ png_do_expand(png_row_infop row_info, png_bytep row,
} }
else if (row_info->bit_depth == 16) else if (row_info->bit_depth == 16)
{ {
png_byte red_high = (png_byte)((trans_value->red >> 8) & 0xff); png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
png_byte green_high = (png_byte)((trans_value->green >> 8) & 0xff); png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
png_byte blue_high = (png_byte)((trans_value->blue >> 8) & 0xff); png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
png_byte red_low = (png_byte)(trans_value->red & 0xff); png_byte red_low = (png_byte)(trans_color->red & 0xff);
png_byte green_low = (png_byte)(trans_value->green & 0xff); png_byte green_low = (png_byte)(trans_color->green & 0xff);
png_byte blue_low = (png_byte)(trans_value->blue & 0xff); png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
sp = row + row_info->rowbytes - 1; sp = row + row_info->rowbytes - 1;
dp = row + (png_size_t)(row_width << 3) - 1; dp = row + (png_size_t)(row_width << 3) - 1;
for (i = 0; i < row_width; i++) for (i = 0; i < row_width; i++)