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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] Version 1.6.0beta20 [March 21, 2012]
Changed chunk handler warnings into benign errors, incrementally load iCCP 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 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] Version 1.6.0beta20 [March 21, 2012]
Changed chunk handler warnings into benign errors, incrementally load iCCP 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 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit (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); sizeof profile_header);
size = (sizeof profile_header) + 12 * tag_count; size = (sizeof profile_header) + 12 * tag_count;
ret = png_inflate_read(png_ptr, local_buffer, ret = png_inflate_read(png_ptr, local_buffer,
sizeof local_buffer, &length, sizeof local_buffer, &length,
profile + (sizeof profile_header), &size, 0); 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) size = profile_length - (sizeof profile_header)
- 12 * tag_count; - 12 * tag_count;
ret = png_inflate_read(png_ptr, local_buffer, ret = png_inflate_read(png_ptr, local_buffer,
sizeof local_buffer, &length, sizeof local_buffer, &length,
profile + (sizeof profile_header) + 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) 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) if (ret != Z_STREAM_END)
png_chunk_warning(png_ptr, png_chunk_warning(png_ptr,
png_ptr->zstream.msg); 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)) if (png_crc_finish(png_ptr, length))
return; 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 */ /* Set the gAMA and cHRM information */
png_icc_set_gAMA_and_cHRM(png_ptr, png_icc_set_gAMA_and_cHRM(png_ptr,
&png_ptr->colorspace, keyword, profile, &png_ptr->colorspace, keyword, profile,
0/*prefer explicit gAMA/cHRM*/); 0/*prefer explicit gAMA/cHRM*/);
/* And steal the profile for info_ptr. */ /* Steal the profile for info_ptr. */
if (info_ptr != NULL) if (info_ptr != NULL)
{ {
png_free_data(png_ptr, info_ptr, png_free_data(png_ptr, info_ptr,