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[devel] Renamed png_set_chop_16() to png_set_strip_16().

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This commit is contained in:
Glenn Randers-Pehrson 2011-06-17 20:04:17 -05:00
parent a7428d443c
commit ab63dd0892
11 changed files with 89 additions and 106 deletions
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18
ANNOUNCE
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@ -1,5 +1,5 @@
Libpng 1.5.4beta05 - June 16, 2011 Libpng 1.5.4beta04 - June 16, 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.
@ -9,20 +9,20 @@ Files available for download:
Source files with LF line endings (for Unix/Linux) and with a Source files with LF line endings (for Unix/Linux) and with a
"configure" script "configure" script
1.5.4beta05.tar.xz (LZMA-compressed, recommended) 1.5.4beta04.tar.xz (LZMA-compressed, recommended)
1.5.4beta05.tar.gz 1.5.4beta04.tar.gz
1.5.4beta05.tar.bz2 1.5.4beta04.tar.bz2
Source files with CRLF line endings (for Windows), without the Source files with CRLF line endings (for Windows), without the
"configure" script "configure" script
lp154b05.7z (LZMA-compressed, recommended) lp154b04.7z (LZMA-compressed, recommended)
lp154b05.zip lp154b04.zip
Other information: Other information:
1.5.4beta05-README.txt 1.5.4beta04-README.txt
1.5.4beta05-LICENSE.txt 1.5.4beta04-LICENSE.txt
Changes since the last public release (1.5.2): Changes since the last public release (1.5.2):
@ -220,8 +220,6 @@ Version 1.5.4beta04 [June 16, 2011]
not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built. not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8 Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
Version 1.5.4beta05 [June 16, 2011]
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
https://lists.sourceforge.net/lists/listinfo/png-mng-implement https://lists.sourceforge.net/lists/listinfo/png-mng-implement

2
CHANGES
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@ -3483,8 +3483,6 @@ Version 1.5.4beta04 [June 16, 2011]
not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built. not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8 Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
Version 1.5.4beta05 [June 16, 2011]
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
https://lists.sourceforge.net/lists/listinfo/png-mng-implement https://lists.sourceforge.net/lists/listinfo/png-mng-implement

4
example.c
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@ -192,9 +192,9 @@ void read_png(FILE *fp, unsigned int sig_read) /* File is already open */
* low byte. * low byte.
*/ */
#ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED #ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
png_set_strip_16(png_ptr); png_set_scale_16(png_ptr);
#else #else
png_set_chop_16(png_ptr); png_set_strip_16(png_ptr);
#endif #endif
/* Strip alpha bytes from the input data without combining with the /* Strip alpha bytes from the input data without combining with the

22
libpng-manual.txt
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@ -1,6 +1,6 @@
libpng-manual.txt - A description on how to use and modify libpng libpng-manual.txt - A description on how to use and modify libpng
libpng version 1.5.4beta05 - June 18, 2011 libpng version 1.5.4beta04 - June 16, 2011
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net> <glennrp at users.sourceforge.net>
Copyright (c) 1998-2011 Glenn Randers-Pehrson Copyright (c) 1998-2011 Glenn Randers-Pehrson
@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng
Based on: Based on:
libpng versions 0.97, January 1998, through 1.5.4beta05 - June 18, 2011 libpng versions 0.97, January 1998, through 1.5.4beta04 - June 16, 2011
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2011 Glenn Randers-Pehrson Copyright (c) 1998-2011 Glenn Randers-Pehrson
@ -847,8 +847,8 @@ interface or libpng API calls for the low level interface. For reference the
settings and API calls required are: settings and API calls required are:
8-bit values: 8-bit values:
PNG_TRANSFORM_SCALE_16 | PNG_EXPAND PNG_TRANSFORM_STRIP_16 | PNG_EXPAND
png_set_expand(png_ptr); png_set_scale_16(png_ptr); png_set_expand(png_ptr); png_set_strip_16(png_ptr);
If you must get exactly the same inaccurate results If you must get exactly the same inaccurate results
produced by default in versions prior to libpng-1.5.4, produced by default in versions prior to libpng-1.5.4,
@ -878,7 +878,7 @@ the entire image into memory, and (b) the input transformations
you want to do are limited to the following set: you want to do are limited to the following set:
PNG_TRANSFORM_IDENTITY No transformation PNG_TRANSFORM_IDENTITY No transformation
PNG_TRANSFORM_SCALE_16 Strip 16-bit samples to PNG_TRANSFORM_STRIP_16 Strip 16-bit samples to
8-bit 8-bit
PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
@ -1404,12 +1404,12 @@ byte, unless png_set_packing() is called. 8-bit RGB data will be stored
in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha() in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
is called to insert filler bytes, either before or after each RGB triplet. is called to insert filler bytes, either before or after each RGB triplet.
16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant 16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
byte of the color value first, unless png_set_scale_16() is called to byte of the color value first, unless png_set_strip_16() is called to
transform it to regular RGB RGB triplets, or png_set_filler() or transform it to regular RGB RGB triplets, or png_set_filler() or
png_set_add alpha() is called to insert filler bytes, either before or png_set_add alpha() is called to insert filler bytes, either before or
after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
be modified with be modified with
png_set_filler(), png_set_add_alpha(), or png_set_scale_16(). png_set_filler(), png_set_add_alpha(), or png_set_strip_16().
The following code transforms grayscale images of less than 8 to 8 bits, The following code transforms grayscale images of less than 8 to 8 bits,
changes paletted images to RGB, and adds a full alpha channel if there is changes paletted images to RGB, and adds a full alpha channel if there is
@ -1446,7 +1446,7 @@ PNG can have files with 16 bits per channel. If you only can handle
8 bits per channel, this will strip the pixels down to 8-bit. 8 bits per channel, this will strip the pixels down to 8-bit.
if (bit_depth == 16) if (bit_depth == 16)
png_set_scale_16(png_ptr); png_set_strip_16(png_ptr);
If you need to process the alpha channel on the image separately from the image If you need to process the alpha channel on the image separately from the image
data (for example if you convert it to a bitmap mask) it is possible to have data (for example if you convert it to a bitmap mask) it is possible to have
@ -4109,7 +4109,7 @@ reading 16-bit images, with none of the pixels being off-by-one any
longer (see Clause 13.12 of the PNG specification). If you must longer (see Clause 13.12 of the PNG specification). If you must
have exactly the same inaccurate results that libpng produced by have exactly the same inaccurate results that libpng produced by
default previously, then you can use the png_set_chop_16() API instead default previously, then you can use the png_set_chop_16() API instead
of png_set_scale_16(). of png_set_strip_16().
Prior to libpng-1.5.4, the png_set_user_limits() function could only be Prior to libpng-1.5.4, the png_set_user_limits() function could only be
used to reduce the width and height limits from the value of used to reduce the width and height limits from the value of
@ -4425,13 +4425,13 @@ Other rules can be inferred by inspecting the libpng source.
XIV. Y2K Compliance in libpng XIV. Y2K Compliance in libpng
June 18, 2011 June 16, 2011
Since the PNG Development group is an ad-hoc body, we can't make Since the PNG Development group is an ad-hoc body, we can't make
an official declaration. an official declaration.
This is your unofficial assurance that libpng from version 0.71 and This is your unofficial assurance that libpng from version 0.71 and
upward through 1.5.4beta05 are Y2K compliant. It is my belief that earlier upward through 1.5.4beta04 are Y2K compliant. It is my belief that earlier
versions were also Y2K compliant. versions were also Y2K compliant.
Libpng only has three year fields. One is a 2-byte unsigned integer that Libpng only has three year fields. One is a 2-byte unsigned integer that

34
libpng.3
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@ -1,6 +1,6 @@
.TH LIBPNG 3 "June 18, 2011" .TH LIBPNG 3 "June 16, 2011"
.SH NAME .SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.5.4beta05 libpng \- Portable Network Graphics (PNG) Reference Library 1.5.4beta04
.SH SYNOPSIS .SH SYNOPSIS
\fI\fB \fI\fB
@ -955,7 +955,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
.SH LIBPNG.TXT .SH LIBPNG.TXT
libpng-manual.txt - A description on how to use and modify libpng libpng-manual.txt - A description on how to use and modify libpng
libpng version 1.5.4beta05 - June 18, 2011 libpng version 1.5.4beta04 - June 16, 2011
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net> <glennrp at users.sourceforge.net>
Copyright (c) 1998-2011 Glenn Randers-Pehrson Copyright (c) 1998-2011 Glenn Randers-Pehrson
@ -966,7 +966,7 @@ libpng-manual.txt - A description on how to use and modify libpng
Based on: Based on:
libpng versions 0.97, January 1998, through 1.5.4beta05 - June 18, 2011 libpng versions 0.97, January 1998, through 1.5.4beta04 - June 16, 2011
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2011 Glenn Randers-Pehrson Copyright (c) 1998-2011 Glenn Randers-Pehrson
@ -1802,8 +1802,8 @@ interface or libpng API calls for the low level interface. For reference the
settings and API calls required are: settings and API calls required are:
8-bit values: 8-bit values:
PNG_TRANSFORM_SCALE_16 | PNG_EXPAND PNG_TRANSFORM_STRIP_16 | PNG_EXPAND
png_set_expand(png_ptr); png_set_scale_16(png_ptr); png_set_expand(png_ptr); png_set_strip_16(png_ptr);
If you must get exactly the same inaccurate results If you must get exactly the same inaccurate results
produced by default in versions prior to libpng-1.5.4, produced by default in versions prior to libpng-1.5.4,
@ -1833,7 +1833,7 @@ the entire image into memory, and (b) the input transformations
you want to do are limited to the following set: you want to do are limited to the following set:
PNG_TRANSFORM_IDENTITY No transformation PNG_TRANSFORM_IDENTITY No transformation
PNG_TRANSFORM_SCALE_16 Strip 16-bit samples to PNG_TRANSFORM_STRIP_16 Strip 16-bit samples to
8-bit 8-bit
PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
@ -2359,12 +2359,12 @@ byte, unless png_set_packing() is called. 8-bit RGB data will be stored
in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha() in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
is called to insert filler bytes, either before or after each RGB triplet. is called to insert filler bytes, either before or after each RGB triplet.
16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant 16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
byte of the color value first, unless png_set_scale_16() is called to byte of the color value first, unless png_set_strip_16() is called to
transform it to regular RGB RGB triplets, or png_set_filler() or transform it to regular RGB RGB triplets, or png_set_filler() or
png_set_add alpha() is called to insert filler bytes, either before or png_set_add alpha() is called to insert filler bytes, either before or
after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
be modified with be modified with
png_set_filler(), png_set_add_alpha(), or png_set_scale_16(). png_set_filler(), png_set_add_alpha(), or png_set_strip_16().
The following code transforms grayscale images of less than 8 to 8 bits, The following code transforms grayscale images of less than 8 to 8 bits,
changes paletted images to RGB, and adds a full alpha channel if there is changes paletted images to RGB, and adds a full alpha channel if there is
@ -2401,7 +2401,7 @@ PNG can have files with 16 bits per channel. If you only can handle
8 bits per channel, this will strip the pixels down to 8-bit. 8 bits per channel, this will strip the pixels down to 8-bit.
if (bit_depth == 16) if (bit_depth == 16)
png_set_scale_16(png_ptr); png_set_strip_16(png_ptr);
If you need to process the alpha channel on the image separately from the image If you need to process the alpha channel on the image separately from the image
data (for example if you convert it to a bitmap mask) it is possible to have data (for example if you convert it to a bitmap mask) it is possible to have
@ -5064,7 +5064,7 @@ reading 16-bit images, with none of the pixels being off-by-one any
longer (see Clause 13.12 of the PNG specification). If you must longer (see Clause 13.12 of the PNG specification). If you must
have exactly the same inaccurate results that libpng produced by have exactly the same inaccurate results that libpng produced by
default previously, then you can use the png_set_chop_16() API instead default previously, then you can use the png_set_chop_16() API instead
of png_set_scale_16(). of png_set_strip_16().
Prior to libpng-1.5.4, the png_set_user_limits() function could only be Prior to libpng-1.5.4, the png_set_user_limits() function could only be
used to reduce the width and height limits from the value of used to reduce the width and height limits from the value of
@ -5380,13 +5380,13 @@ Other rules can be inferred by inspecting the libpng source.
.SH XIV. Y2K Compliance in libpng .SH XIV. Y2K Compliance in libpng
June 18, 2011 June 16, 2011
Since the PNG Development group is an ad-hoc body, we can't make Since the PNG Development group is an ad-hoc body, we can't make
an official declaration. an official declaration.
This is your unofficial assurance that libpng from version 0.71 and This is your unofficial assurance that libpng from version 0.71 and
upward through 1.5.4beta05 are Y2K compliant. It is my belief that earlier upward through 1.5.4beta04 are Y2K compliant. It is my belief that earlier
versions were also Y2K compliant. versions were also Y2K compliant.
Libpng only has three year fields. One is a 2-byte unsigned integer that Libpng only has three year fields. One is a 2-byte unsigned integer that
@ -5579,7 +5579,7 @@ the first widely used release:
1.5.3rc01-02 15 10503 15.so.15.3[.0] 1.5.3rc01-02 15 10503 15.so.15.3[.0]
1.5.3beta11 15 10503 15.so.15.3[.0] 1.5.3beta11 15 10503 15.so.15.3[.0]
1.5.3 [omitted] 1.5.3 [omitted]
1.5.4beta01-05 15 10504 15.so.15.4[.0] 1.5.4beta01-03 15 10504 15.so.15.4[.0]
Henceforth the source version will match the shared-library minor Henceforth the source version will match the shared-library minor
and patch numbers; the shared-library major version number will be and patch numbers; the shared-library major version number will be
@ -5636,7 +5636,7 @@ possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation. Thanks to Frank J. T. Wojcik for helping with the documentation.
Libpng version 1.5.4beta05 - June 18, 2011: Libpng version 1.5.4beta04 - June 16, 2011:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
@ -5659,7 +5659,7 @@ this sentence.
This code is released under the libpng license. This code is released under the libpng license.
libpng versions 1.2.6, August 15, 2004, through 1.5.4beta05, June 18, 2011, are libpng versions 1.2.6, August 15, 2004, through 1.5.4beta04, June 16, 2011, are
Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.2.5 distributed according to the same disclaimer and license as libpng-1.2.5
with the following individual added to the list of Contributing Authors with the following individual added to the list of Contributing Authors
@ -5758,7 +5758,7 @@ certification mark of the Open Source Initiative.
Glenn Randers-Pehrson Glenn Randers-Pehrson
glennrp at users.sourceforge.net glennrp at users.sourceforge.net
June 18, 2011 June 16, 2011
.\" end of man page .\" end of man page

8
png.c
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@ -617,13 +617,13 @@ png_get_copyright(png_const_structp png_ptr)
#else #else
# ifdef __STDC__ # ifdef __STDC__
return PNG_STRING_NEWLINE \ return PNG_STRING_NEWLINE \
"libpng version 1.5.4beta05 - June 16, 2011" PNG_STRING_NEWLINE \ "libpng version 1.5.4beta05 - June 18, 2011" PNG_STRING_NEWLINE \
"Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ "Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
"Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
"Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
PNG_STRING_NEWLINE; PNG_STRING_NEWLINE;
# else # else
return "libpng version 1.5.4beta05 - June 16, 2011\ return "libpng version 1.5.4beta05 - June 18, 2011\
Copyright (c) 1998-2011 Glenn Randers-Pehrson\ Copyright (c) 1998-2011 Glenn Randers-Pehrson\
Copyright (c) 1996-1997 Andreas Dilger\ Copyright (c) 1996-1997 Andreas Dilger\
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."; Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@ -2369,7 +2369,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
else else
shift = 0; /* keep all 16 bits */ shift = 0; /* keep all 16 bits */
if (png_ptr->transformations & (PNG_16_TO_8 | PNG_CHOP_16_TO_8)) if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
{ {
/* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
* the significant bits in the *input* when the output will * the significant bits in the *input* when the output will
@ -2390,7 +2390,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
* 16-bit output because the 8-bit table assumes the result will be reduced * 16-bit output because the 8-bit table assumes the result will be reduced
* to 8 bits. * to 8 bits.
*/ */
if (png_ptr->transformations & (PNG_16_TO_8 | PNG_CHOP_16_TO_8)) if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8))
#endif #endif
png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift, png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
png_ptr->screen_gamma > 0 ? png_product2(png_ptr->gamma, png_ptr->screen_gamma > 0 ? png_product2(png_ptr->gamma,

7
png.h
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@ -902,7 +902,7 @@ PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */ #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
/* Added to libpng-1.5.4 */ /* Added to libpng-1.5.4 */
#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */ #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
#define PNG_TRANSFORM_CHOP_16 0x8000 /* read only */ #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
/* Flags for MNG supported features */ /* Flags for MNG supported features */
#define PNG_FLAG_MNG_EMPTY_PLTE 0x01 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
@ -1428,9 +1428,10 @@ PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structp png_ptr,
/* Scale a 16-bit depth file down to 8-bit, accurately. */ /* Scale a 16-bit depth file down to 8-bit, accurately. */
PNG_EXPORT(48, void, png_set_scale_16, (png_structp png_ptr)); PNG_EXPORT(48, void, png_set_scale_16, (png_structp png_ptr));
# endif # endif
# ifdef PNG_READ_CHOP_16_TO_8_SUPPORTED
# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
/* Strip the second byte of information from a 16-bit depth file. */ /* Strip the second byte of information from a 16-bit depth file. */
PNG_EXPORT(229, void, png_set_chop_16, (png_structp png_ptr)); PNG_EXPORT(229, void, png_set_strip_16, (png_structp png_ptr));
# endif # endif
#endif #endif

4
pngpriv.h
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@ -298,7 +298,7 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
#define PNG_ENCODE_ALPHA 0x800000L /* Added to libpng-1.5.4 */ #define PNG_ENCODE_ALPHA 0x800000L /* Added to libpng-1.5.4 */
#define PNG_ADD_ALPHA 0x1000000L /* Added to libpng-1.2.7 */ #define PNG_ADD_ALPHA 0x1000000L /* Added to libpng-1.2.7 */
#define PNG_EXPAND_tRNS 0x2000000L /* Added to libpng-1.2.9 */ #define PNG_EXPAND_tRNS 0x2000000L /* Added to libpng-1.2.9 */
#define PNG_CHOP_16_TO_8 0x4000000L #define PNG_SCALE_16_TO_8 0x4000000L
/* 0x8000000L unused */ /* 0x8000000L unused */
/* 0x10000000L unused */ /* 0x10000000L unused */
/* 0x20000000L unused */ /* 0x20000000L unused */
@ -824,7 +824,7 @@ PNG_EXTERN void png_do_scale_16_to_8 PNGARG((png_row_infop row_info,
png_bytep row)); png_bytep row));
#endif #endif
#ifdef PNG_READ_CHOP_16_TO_8_SUPPORTED #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info, PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info,
png_bytep row)); png_bytep row));
#endif #endif

8
pngread.c
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@ -1290,16 +1290,16 @@ png_read_png(png_structp png_ptr, png_infop info_ptr,
/* Tell libpng to strip 16-bit/color files down to 8 bits per color. /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
*/ */
# ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED # ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
if (transforms & PNG_TRANSFORM_STRIP_16) if (transforms & PNG_TRANSFORM_SCALE_16)
png_set_scale_16(png_ptr); png_set_scale_16(png_ptr);
# endif # endif
# ifdef PNG_READ_CHOP_16_TO_8_SUPPORTED # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
/* Added at libpng-1.5.4. "strip_16" produces the same result that it /* Added at libpng-1.5.4. "strip_16" produces the same result that it
* did in earlier versions, while "scale_16" is now more accurate. * did in earlier versions, while "scale_16" is now more accurate.
*/ */
else else
if (transforms & PNG_TRANSFORM_CHOP_16) if (transforms & PNG_TRANSFORM_STRIP_16)
png_set_chop_16(png_ptr); png_set_strip_16(png_ptr);
#endif #endif
#endif #endif

26
pngrtran.c
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@ -134,7 +134,7 @@ png_set_background(png_structp png_ptr,
#ifdef PNG_READ_16_TO_8_SUPPORTED #ifdef PNG_READ_16_TO_8_SUPPORTED
/* Scale 16-bit depth files to 8-bit depth */ /* Scale 16-bit depth files to 8-bit depth */
# ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
void PNGAPI void PNGAPI
png_set_scale_16(png_structp png_ptr) png_set_scale_16(png_structp png_ptr)
{ {
@ -143,26 +143,26 @@ png_set_scale_16(png_structp png_ptr)
if (png_ptr == NULL) if (png_ptr == NULL)
return; return;
png_ptr->transformations |= PNG_16_TO_8; png_ptr->transformations |= PNG_SCALE_16_TO_8;
# ifdef PNG_READ_CHOP_16_TO_8_SUPPORTED # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
png_ptr->transformations &= ~PNG_CHOP_16_TO_8; png_ptr->transformations &= ~PNG_16_TO_8;
# endif # endif
} }
# endif # endif
# ifdef PNG_READ_CHOP_16_TO_8_SUPPORTED # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
/* Chop 16-bit depth files to 8-bit depth */ /* Chop 16-bit depth files to 8-bit depth */
void PNGAPI void PNGAPI
png_set_chop_16(png_structp png_ptr) png_set_strip_16(png_structp png_ptr)
{ {
png_debug(1, "in png_set_chop_16"); png_debug(1, "in png_set_strip_16");
if (png_ptr == NULL) if (png_ptr == NULL)
return; return;
png_ptr->transformations |= PNG_CHOP_16_TO_8; png_ptr->transformations |= PNG_16_TO_8;
# ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
png_ptr->transformations &= ~PNG_16_TO_8; png_ptr->transformations &= ~PNG_SCALE_16_TO_8;
# endif # endif
} }
# endif # endif
@ -1334,7 +1334,7 @@ png_init_read_transformations(png_structp png_ptr)
* 6) PNG_GAMMA * 6) PNG_GAMMA
* 7) PNG_STRIP_ALPHA (if compose) * 7) PNG_STRIP_ALPHA (if compose)
* 8) PNG_ENCODE_ALPHA * 8) PNG_ENCODE_ALPHA
* 9) PNG_16_TO_8 or PNG_CHOP_16_TO_8 (strip16/chop16) * 9) PNG_16_TO_8 or PNG_SCALE_16_TO_8 (strip16/scale16)
* 10) PNG_QUANTIZE (converts to palette) * 10) PNG_QUANTIZE (converts to palette)
* 11) PNG_EXPAND_16 * 11) PNG_EXPAND_16
* 12) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY * 12) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
@ -1874,14 +1874,14 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
#ifdef PNG_READ_16_TO_8_SUPPORTED #ifdef PNG_READ_16_TO_8_SUPPORTED
#ifdef PNG_READ_16BIT_SUPPORTED #ifdef PNG_READ_16BIT_SUPPORTED
if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_CHOP_16_TO_8)) && if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) &&
(info_ptr->bit_depth == 16)) (info_ptr->bit_depth == 16))
info_ptr->bit_depth = 8; info_ptr->bit_depth = 8;
#else #else
/* Force chopping 16-bit input down to 8 */ /* Force chopping 16-bit input down to 8 */
if (info_ptr->bit_depth == 16) if (info_ptr->bit_depth == 16)
{ {
if (!(png_ptr->transformations & PNG_CHOP_16_TO_8)) if (!(png_ptr->transformations & PNG_SCALE_16_TO_8))
png_ptr->transformations |=PNG_16_TO_8; png_ptr->transformations |=PNG_16_TO_8;
info_ptr->bit_depth = 8; info_ptr->bit_depth = 8;
} }

46
pngvalid.c
View File

@ -5240,9 +5240,7 @@ IT(expand_16);
#define PT ITSTRUCT(expand_16) #define PT ITSTRUCT(expand_16)
#endif /* PNG_READ_EXPAND_16_SUPPORTED */ #endif /* PNG_READ_EXPAND_16_SUPPORTED */
#ifdef PNG_READ_16_TO_8_SUPPORTED #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
# if !defined(PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED) && \
!defined(PNG_READ_CHOP_16_TO_8_SUPPORTED) /* the default before 1.5.4 */
/* png_set_scale_16 */ /* png_set_scale_16 */
static void static void
image_transform_png_set_scale_16_set(PNG_CONST image_transform *this, image_transform_png_set_scale_16_set(PNG_CONST image_transform *this,
@ -5263,21 +5261,6 @@ image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this,
if (that->green_sBIT > 8) that->green_sBIT = 8; if (that->green_sBIT > 8) that->green_sBIT = 8;
if (that->blue_sBIT > 8) that->blue_sBIT = 8; if (that->blue_sBIT > 8) that->blue_sBIT = 8;
if (that->alpha_sBIT > 8) that->alpha_sBIT = 8; if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
/* The strip 16 algorithm drops the low 8 bits rather than calculating
* 1/257, so we need to adjust the permitted errors appropriately:
* Notice that this is only relevant prior to the addition of the
* png_set_chop_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
*/
{
PNG_CONST double d = (255-128.5)/65535;
that->rede += d;
that->greene += d;
that->bluee += d;
that->alphae += d;
}
# endif
} }
this->next->mod(this->next, that, pp, display); this->next->mod(this->next, that, pp, display);
@ -5300,18 +5283,18 @@ IT(scale_16);
#define PT ITSTRUCT(scale_16) #define PT ITSTRUCT(scale_16)
#endif #endif
#ifdef PNG_READ_CHOP_16_TO_8_SUPPORTED /* API added in 1.5.4 */ #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED /* the default before 1.5.4 */
/* png_set_chop_16 */ /* png_set_strip_16 */
static void static void
image_transform_png_set_chop_16_set(PNG_CONST image_transform *this, image_transform_png_set_strip_16(PNG_CONST image_transform *this,
transform_display *that, png_structp pp, png_infop pi) transform_display *that, png_structp pp, png_infop pi)
{ {
png_set_chop_16(pp); png_set_strip_16(pp);
this->next->set(this->next, that, pp, pi); this->next->set(this->next, that, pp, pi);
} }
static void static void
image_transform_png_set_chop_16_mod(PNG_CONST image_transform *this, image_transform_png_set_strip_16(PNG_CONST image_transform *this,
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
{ {
if (that->bit_depth == 16) if (that->bit_depth == 16)
@ -5322,8 +5305,11 @@ image_transform_png_set_chop_16_mod(PNG_CONST image_transform *this,
if (that->blue_sBIT > 8) that->blue_sBIT = 8; if (that->blue_sBIT > 8) that->blue_sBIT = 8;
if (that->alpha_sBIT > 8) that->alpha_sBIT = 8; if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
/* From 1.5.4 there is a separate API to do the low byte drop; see the # ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
* comments above for why this requires the following: /* The strip 16 algorithm drops the low 8 bits rather than calculating
* 1/257, so we need to adjust the permitted errors appropriately:
* Notice that this is only relevant prior to the addition of the
* png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
*/ */
{ {
PNG_CONST double d = (255-128.5)/65535; PNG_CONST double d = (255-128.5)/65535;
@ -5332,13 +5318,14 @@ image_transform_png_set_chop_16_mod(PNG_CONST image_transform *this,
that->bluee += d; that->bluee += d;
that->alphae += d; that->alphae += d;
} }
# endif
} }
this->next->mod(this->next, that, pp, display); this->next->mod(this->next, that, pp, display);
} }
static int static int
image_transform_png_set_chop_16_add(image_transform *this, image_transform_png_set_strip_16(image_transform *this,
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
{ {
UNUSED(colour_type) UNUSED(colour_type)
@ -5349,11 +5336,10 @@ image_transform_png_set_chop_16_add(image_transform *this,
return bit_depth > 8; return bit_depth > 8;
} }
IT(chop_16); IT(strip_16);
#undef PT #undef PT
#define PT ITSTRUCT(chop_16) #define PT ITSTRUCT(strip_16)
#endif /* PNG_READ_CHOP_16_TO_8_SUPPORTED, from libpng 1.5.4 */ #endif /* PNG_READ_STRIP_16_TO_8_SUPPORTED, from libpng 1.5.4 */
#endif /* PNG_READ_16_TO_8_SUPPORTED */
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
/* png_set_strip_alpha */ /* png_set_strip_alpha */