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[libpng16] Recognize known sRGB ICC profiles while reading and issue a warning

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about it, if PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED is defined.
This commit is contained in:
Glenn Randers-Pehrson
2012-03-28 10:58:01 -05:00
parent 13a87d9682
commit 48015617d3
5 changed files with 81 additions and 44 deletions
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4
ANNOUNCE
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@@ -341,8 +341,8 @@ Version 1.6.0beta19 [March 18,2012]
Version 1.6.0beta20 [March 28, 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.
Recognize known sRGB ICC profiles while reading and issue a warning about
it, if PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED is defined.
Added checksum-icc.c to contrib/tools
Send comments/corrections/commendations to png-mng-implement at lists.sf.net

4
CHANGES
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@@ -4092,8 +4092,8 @@ Version 1.6.0beta19 [March 18, 2012]
Version 1.6.0beta20 [March 28, 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.
Recognize known sRGB ICC profiles while reading and issue a warning about
it, if PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED is defined.
Added checksum-icc.c to contrib/tools
Send comments/corrections/commendations to png-mng-implement at lists.sf.net

111
pngrutil.c
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@@ -1314,6 +1314,67 @@ png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
#endif /* PNG_READ_sRGB_SUPPORTED */
#ifdef PNG_READ_iCCP_SUPPORTED
#ifdef PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
int /* PRIVATE */
png_compare_ICC_profile_with_sRGB(png_structrp png_ptr, png_bytep profile,
png_uint_32 length)
{
/* See if it's a known sRGB profile. If it is, return intent;
* if not, return -1.
*/
int
icheck;
/* Known sRGB profiles:
* 0: not a known sRGB profile
* 1: HP-Microsoft sRGB v2 perceptual
* 2: ICC sRGB v4 perceptual
* 3: ICC sRGB v2 perceptual
* no black-compensation
*/
typedef struct png_sRGB_check_struct
{
uLong crc;
uLong adler;
png_uint_32 check_len;
int intent;
} png_sRGB_check;
png_sRGB_check check[3] =
{
{ 0xf29e526dUL, 0x0398f3fcUL, 3144UL, 0 },
{ 0xbbef7812UL, 0x209c35d2UL, 60960UL, 0 },
{ 0x427ebb21UL, 0x4909e5e1UL, 3052UL, 0 }
};
if (png_ptr == NULL)
return -1;
for (icheck = 2; icheck >= 0; icheck--)
{
if (length == check[icheck].check_len)
{
uLong profile_adler = adler32(1, profile, length);
if (profile_adler == (uLong) check[icheck].adler)
{
uLong profile_crc = crc32(0, profile, length);
if (profile_crc == (uLong) check[icheck].crc)
return check[icheck].intent;
else
return -1;
}
}
}
return -1;
}
#endif
void /* PRIVATE */
png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
/* Note: this does not properly handle profiles that are > 64K under DOS */
@@ -1460,23 +1521,10 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
if (size == 0)
{
#ifdef PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
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};
intent;
#endif
if (ret != Z_STREAM_END)
png_chunk_warning(png_ptr,
@@ -1495,31 +1543,16 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
if (png_crc_finish(png_ptr, length))
return;
#ifdef PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
/* See if it's a known sRGB profile. */
intent =
png_compare_ICC_profile_with_sRGB(
png_ptr, profile, profile_length);
for (icheck=3; icheck > 0; icheck--)
{
if (profile_length == check_len[icheck])
{
uLong 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);
return;
}
}
}
if (intent >= 0)
png_chunk_warning(png_ptr,
"describes sRGB\n");
#endif
/* Set the gAMA and cHRM information */
png_icc_set_gAMA_and_cHRM(png_ptr,

3
scripts/pnglibconf.dfa
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@@ -650,6 +650,9 @@ option CHECK_FOR_INVALID_INDEX enables WRITE_CHECK_FOR_INVALID_INDEX
option READ_CHECK_FOR_INVALID_INDEX requires READ CHECK_FOR_INVALID_INDEX
option WRITE_CHECK_FOR_INVALID_INDEX requires WRITE CHECK_FOR_INVALID_INDEX
# added at libpng-1.6.0
option WARN_IF_iCCP_IS_sRGB requires READ iCCP
# Simplified API options (added at libpng-1.6.0)
# Read:
option SIMPLIFIED_READ requires SEQUENTIAL_READ READ_TRANSFORMS SETJMP

3
scripts/pnglibconf.h.prebuilt
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@@ -3,7 +3,7 @@
/* pnglibconf.h - library build configuration */
/* Libpng 1.6.0beta20 - March 21, 2012 */
/* Libpng 1.6.0beta20 - March 28, 2012 */
/* Copyright (c) 1998-2012 Glenn Randers-Pehrson */
@@ -138,6 +138,7 @@
#define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
#define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
#define PNG_SIMPLIFIED_WRITE_SUPPORTED
#define PNG_WARN_IF_iCCP_IS_sRGB_SUPPORTED
#define PNG_sPLT_SUPPORTED
#define PNG_sRGB_SUPPORTED
#define PNG_STDIO_SUPPORTED