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[libpng16] Recognize known sRGB ICC profiles while reading and handle them as

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if the sRGB chunk had appeared instead.
This commit is contained in:
Glenn Randers-Pehrson 2012-03-21 09:18:15 -05:00
parent b11b31aea2
commit 8fbd60ded2
3 changed files with 53 additions and 1 deletions
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2
ANNOUNCE
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@ -341,6 +341,8 @@ Version 1.6.0beta19 [March 18,2012]
Version 1.6.0beta20 [March 21, 2012]
Changed chunk handler warnings into benign errors, incrementally load iCCP
Recognize known sRGB ICC profiles while reading and handle them as if the
sRGB chunk had appeared instead.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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2
CHANGES
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@ -4092,6 +4092,8 @@ Version 1.6.0beta19 [March 18, 2012]
Version 1.6.0beta20 [March 21, 2012]
Changed chunk handler warnings into benign errors, incrementally load iCCP
Recognize known sRGB ICC profiles while reading and handle them as if the
sRGB chunk had appeared instead.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

50
pngrutil.c
View File

@ -1436,6 +1436,7 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
sizeof profile_header);
size = (sizeof profile_header) + 12 * tag_count;
ret = png_inflate_read(png_ptr, local_buffer,
sizeof local_buffer, &length,
profile + (sizeof profile_header), &size, 0);
@ -1451,6 +1452,7 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
*/
size = profile_length - (sizeof profile_header)
- 12 * tag_count;
ret = png_inflate_read(png_ptr, local_buffer,
sizeof local_buffer, &length,
profile + (sizeof profile_header) +
@ -1458,6 +1460,24 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
if (size == 0)
{
int
icheck;
/* Known sRGB profiles:
* 0: not a known sRGB profile
* 1: HP-Microsoft sRGB v2
* 2: ICC sRGB v4 perceptual
* 3: ICC sRGB v2 perceptual
* no black-compensation
*/
png_uint_32 check_crc[4] = {0,
0xf29e526dUL, 0xbbef7812UL,
0x427ebb21UL},
check_len[4] = {0, 3144, 60960,
3052};
if (ret != Z_STREAM_END)
png_chunk_warning(png_ptr,
png_ptr->zstream.msg);
@ -1475,12 +1495,40 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
if (png_crc_finish(png_ptr, length))
return;
/* See if it's a known sRGB profile. */
for (icheck=3; icheck > 0; icheck--)
{
if (profile_length == check_len[icheck])
{
png_uint_32 profile_crc = crc32(0,
profile, profile_length);
if (profile_crc ==
check_crc[icheck])
{
(void)png_colorspace_set_sRGB(
png_ptr,
&png_ptr->colorspace,
PNG_sRGB_INTENT_PERCEPTUAL,
0);
png_colorspace_sync(png_ptr,
info_ptr);
png_free(png_ptr, profile);
return;
}
}
}
/* Set the gAMA and cHRM information */
png_icc_set_gAMA_and_cHRM(png_ptr,
&png_ptr->colorspace, keyword, profile,
0/*prefer explicit gAMA/cHRM*/);
/* And steal the profile for info_ptr. */
/* Steal the profile for info_ptr. */
if (info_ptr != NULL)
{
png_free_data(png_ptr, info_ptr,