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[libpng12] Removed WRITE_WEIGHTED_FILTERED code, reformatted LICENSE.

This commit is contained in:
Glenn Randers-Pehrson 2015-07-13 13:36:29 -05:00
parent b9a5aee331
commit d5b51a49a9
8 changed files with 66 additions and 719 deletions
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5
ANNOUNCE
View File

@ -1,5 +1,5 @@
Libpng 1.2.54beta01 - May 15, 2015
Libpng 1.2.54beta01 - July 13, 2015
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.
@ -43,12 +43,13 @@ Other information:
Changes since the last public release (1.2.53):
version 1.2.54beta01 [May 15, 2015]
version 1.2.54beta01 [July 13, 2015]
Fix typecast in a png_debug2() statement in png_set_text_2() to
avoid a compiler warning in PNG_DEBUG builds.
Fixed printf formats in pngtest.c to avoid compiler warnings and a
Coverity warning in PNG_DEBUG builds.
Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c PNG_DEBUG builds.
Removed WRITE_WEIGHTED_FILTERED code.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

6
CHANGES
View File

@ -469,7 +469,7 @@ version 1.0.3d [September 4, 1999]
Added new png_expand functions to scripts/pngdef.pas and pngos2.def
Added a demo read_user_transform_fn that examines the row filters in pngtest.c
version 1.0.4 [September 24, 1999]
Version 1.0.4 [September 24, 1999, not distributed publicly]
Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
Made several minor corrections to pngtest.c
@ -493,6 +493,7 @@ version 1.0.4c [October 1, 1999]
Added a "png_check_version" function in png.c and pngtest.c that will generate
a helpful compiler error if an old png.h is found in the search path.
Changed type of png_user_transform_depth|channels from int to png_byte.
Added "Libpng is OSI Certified Open Source Software" statement to png.h
version 1.0.4d [October 6, 1999]
Changed 0.45 to 0.45455 in png_set_sRGB()
Removed unused PLTE entries from pngnow.png
@ -2857,12 +2858,13 @@ version 1.2.53rc02 [February 21, 2015]
versions 1.0.63 and 1.2.53 [February 26, 2015]
No changes.
version 1.2.54beta01 [May 15, 2015]
version 1.2.54beta01 [July 13, 2015]
Fixed typecast in a png_debug2() statement in png_set_text_2() to
avoid a compiler warning in PNG_DEBUG builds.
Fixed printf formats in pngtest.c to avoid compiler warnings and a
Coverity warning in PNG_DEBUG builds.
Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c PNG_DEBUG builds.
Removed WRITE_WEIGHTED_FILTERED code.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

46
LICENSE
View File

@ -10,20 +10,14 @@ this sentence.
This code is released under the libpng license.
libpng versions 1.2.6, August 15, 2004, through 1.2.54beta01, May 9, 2015, are
Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.2.5
with the following individual added to the list of Contributing Authors
Cosmin Truta
libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
libpng versions 1.0.7, July 1, 2000, through 1.2.54beta01, July 13, 2015, are
Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.0.6
with the following individuals added to the list of Contributing Authors
with the following individuals added to the list of Contributing Authors:
Simon-Pierre Cadieux
Eric S. Raymond
Cosmin Truta
Gilles Vollant
and with the following additions to the disclaimer:
@ -36,17 +30,17 @@ and with the following additions to the disclaimer:
the user.
libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-0.96,
with the following individuals added to the list of Contributing Authors:
Copyright (c) 1998-2000 Glenn Randers-Pehrson, and are distributed according
to the same disclaimer and license as libpng-0.96, with the following
individuals added to the list of Contributing Authors:
Tom Lane
Glenn Randers-Pehrson
Willem van Schaik
libpng versions 0.89, June 1996, through 0.96, May 1997, are
Copyright (c) 1996, 1997 Andreas Dilger
Distributed according to the same disclaimer and license as libpng-0.88,
Copyright (c) 1996-1997 Andreas Dilger, and are
distributed according to the same disclaimer and license as libpng-0.88,
with the following individuals added to the list of Contributing Authors:
John Bowler
@ -57,7 +51,7 @@ with the following individuals added to the list of Contributing Authors:
Tom Tanner
libpng versions 0.5, May 1995, through 0.88, January 1996, are
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
For the purposes of this copyright and license, "Contributing Authors"
is defined as the following set of individuals:
@ -80,13 +74,13 @@ Permission is hereby granted to use, copy, modify, and distribute this
source code, or portions hereof, for any purpose, without fee, subject
to the following restrictions:
1. The origin of this source code must not be misrepresented.
1. The origin of this source code must not be misrepresented.
2. Altered versions must be plainly marked as such and must not
be misrepresented as being the original source.
2. Altered versions must be plainly marked as such and must not
be misrepresented as being the original source.
3. This Copyright notice may not be removed or altered from any
source or altered source distribution.
3. This Copyright notice may not be removed or altered from any
source or altered source distribution.
The Contributing Authors and Group 42, Inc. specifically permit, without
fee, and encourage the use of this source code as a component to
@ -94,18 +88,18 @@ supporting the PNG file format in commercial products. If you use this
source code in a product, acknowledgment is not required but would be
appreciated.
A "png_get_copyright" function is available, for convenient use in "about"
boxes and the like:
printf("%s",png_get_copyright(NULL));
printf("%s", png_get_copyright(NULL));
Also, the PNG logo (in PNG format, of course) is supplied in the
files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a
certification mark of the Open Source Initiative.
Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
a certification mark of the Open Source Initiative. OSI has not addressed
the additional disclaimers inserted at version 1.0.7.
Glenn Randers-Pehrson
glennrp at users.sourceforge.net
May 9, 2015
July 13, 2015

41
libpng-1.2.54beta01.txt
View File

@ -1,6 +1,6 @@
libpng.txt - A description on how to use and modify libpng
libpng version 1.2.54beta01 - May 9, 2015
libpng version 1.2.54beta01 - July 13, 2015
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2014 Glenn Randers-Pehrson
@ -11,7 +11,7 @@ libpng.txt - A description on how to use and modify libpng
Based on:
libpng versions 0.97, January 1998, through 1.2.54beta01 - May 9, 2015
libpng versions 0.97, January 1998, through 1.2.54beta01 - July 13, 2015
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2014 Glenn Randers-Pehrson
@ -2757,41 +2757,6 @@ is called for the first time.)
same as the value of filter_method used
in png_set_IHDR().
It is also possible to influence how libpng chooses from among the
available filters. This is done in one or both of two ways - by
telling it how important it is to keep the same filter for successive
rows, and by telling it the relative computational costs of the filters.
double weights[3] = {1.5, 1.3, 1.1},
costs[PNG_FILTER_VALUE_LAST] =
{1.0, 1.3, 1.3, 1.5, 1.7};
png_set_filter_heuristics(png_ptr,
PNG_FILTER_HEURISTIC_WEIGHTED, 3,
weights, costs);
The weights are multiplying factors that indicate to libpng that the
row filter should be the same for successive rows unless another row filter
is that many times better than the previous filter. In the above example,
if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
"sum of absolute differences" 1.5 x 1.3 times higher than other filters
and still be chosen, while the NONE filter could have a sum 1.1 times
higher than other filters and still be chosen. Unspecified weights are
taken to be 1.0, and the specified weights should probably be declining
like those above in order to emphasize recent filters over older filters.
The filter costs specify for each filter type a relative decoding cost
to be considered when selecting row filters. This means that filters
with higher costs are less likely to be chosen over filters with lower
costs, unless their "sum of absolute differences" is that much smaller.
The costs do not necessarily reflect the exact computational speeds of
the various filters, since this would unduly influence the final image
size.
Note that the numbers above were invented purely for this example and
are given only to help explain the function usage. Little testing has
been done to find optimum values for either the costs or the weights.
Removing unwanted object code
There are a bunch of #define's in pngconf.h that control what parts of
@ -3183,7 +3148,7 @@ Other rules can be inferred by inspecting the libpng source.
XIII. Y2K Compliance in libpng
May 9, 2015
July 13, 2015
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.

147
libpng.3
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@ -1,4 +1,4 @@
.TH LIBPNG 3 "May 9, 2015"
.TH LIBPNG 3 "July 13, 2015"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.2.54beta01
.SH SYNOPSIS
@ -410,7 +410,7 @@ Following is a copy of the libpng.txt file that accompanies libpng.
.SH LIBPNG.TXT
libpng.txt - A description on how to use and modify libpng
libpng version 1.2.54beta01 - May 9, 2015
libpng version 1.2.54beta01 - July 13, 2015
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2014 Glenn Randers-Pehrson
@ -421,7 +421,7 @@ libpng.txt - A description on how to use and modify libpng
Based on:
libpng versions 0.97, January 1998, through 1.2.54beta01 - May 9, 2015
libpng versions 0.97, January 1998, through 1.2.54beta01 - July 13, 2015
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2014 Glenn Randers-Pehrson
@ -3167,41 +3167,6 @@ is called for the first time.)
same as the value of filter_method used
in png_set_IHDR().
It is also possible to influence how libpng chooses from among the
available filters. This is done in one or both of two ways - by
telling it how important it is to keep the same filter for successive
rows, and by telling it the relative computational costs of the filters.
double weights[3] = {1.5, 1.3, 1.1},
costs[PNG_FILTER_VALUE_LAST] =
{1.0, 1.3, 1.3, 1.5, 1.7};
png_set_filter_heuristics(png_ptr,
PNG_FILTER_HEURISTIC_WEIGHTED, 3,
weights, costs);
The weights are multiplying factors that indicate to libpng that the
row filter should be the same for successive rows unless another row filter
is that many times better than the previous filter. In the above example,
if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
"sum of absolute differences" 1.5 x 1.3 times higher than other filters
and still be chosen, while the NONE filter could have a sum 1.1 times
higher than other filters and still be chosen. Unspecified weights are
taken to be 1.0, and the specified weights should probably be declining
like those above in order to emphasize recent filters over older filters.
The filter costs specify for each filter type a relative decoding cost
to be considered when selecting row filters. This means that filters
with higher costs are less likely to be chosen over filters with lower
costs, unless their "sum of absolute differences" is that much smaller.
The costs do not necessarily reflect the exact computational speeds of
the various filters, since this would unduly influence the final image
size.
Note that the numbers above were invented purely for this example and
are given only to help explain the function usage. Little testing has
been done to find optimum values for either the costs or the weights.
.SS Removing unwanted object code
There are a bunch of #define's in pngconf.h that control what parts of
@ -3593,7 +3558,7 @@ Other rules can be inferred by inspecting the libpng source.
.SH XIII. Y2K Compliance in libpng
May 9, 2015
July 13, 2015
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.
@ -3990,7 +3955,7 @@ possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation.
Libpng version 1.2.54beta01 - May 9, 2015:
Libpng version 1.2.54beta01 - July 13, 2015:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
@ -4013,106 +3978,8 @@ this sentence.
This code is released under the libpng license.
libpng versions 1.2.6, August 15, 2004, through 1.2.54beta01, May 9, 2015, are
Copyright (c) 2004,2006-2015 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.2.5
with the following individual added to the list of Contributing Authors
Cosmin Truta
libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
libpng versions 1.0.7, July 1, 2000, through 1.2.54beta01, July 13, 2015, are
Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.0.6
with the following individuals added to the list of Contributing Authors
Simon-Pierre Cadieux
Eric S. Raymond
Gilles Vollant
and with the following additions to the disclaimer:
There is no warranty against interference with your
enjoyment of the library or against infringement.
There is no warranty that our efforts or the library
will fulfill any of your particular purposes or needs.
This library is provided with all faults, and the entire
risk of satisfactory quality, performance, accuracy, and
effort is with the user.
libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
Copyright (c) 1998, 1999 Glenn Randers-Pehrson
Distributed according to the same disclaimer and license as libpng-0.96,
with the following individuals added to the list of Contributing Authors:
Tom Lane
Glenn Randers-Pehrson
Willem van Schaik
libpng versions 0.89, June 1996, through 0.96, May 1997, are
Copyright (c) 1996, 1997 Andreas Dilger
Distributed according to the same disclaimer and license as libpng-0.88,
with the following individuals added to the list of Contributing Authors:
John Bowler
Kevin Bracey
Sam Bushell
Magnus Holmgren
Greg Roelofs
Tom Tanner
libpng versions 0.5, May 1995, through 0.88, January 1996, are
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
For the purposes of this copyright and license, "Contributing Authors"
is defined as the following set of individuals:
Andreas Dilger
Dave Martindale
Guy Eric Schalnat
Paul Schmidt
Tim Wegner
The PNG Reference Library is supplied "AS IS". The Contributing Authors
and Group 42, Inc. disclaim all warranties, expressed or implied,
including, without limitation, the warranties of merchantability and of
fitness for any purpose. The Contributing Authors and Group 42, Inc.
assume no liability for direct, indirect, incidental, special, exemplary,
or consequential damages, which may result from the use of the PNG
Reference Library, even if advised of the possibility of such damage.
Permission is hereby granted to use, copy, modify, and distribute this
source code, or portions hereof, for any purpose, without fee, subject
to the following restrictions:
1. The origin of this source code must not be misrepresented.
2. Altered versions must be plainly marked as such and
must not be misrepresented as being the original source.
3. This Copyright notice may not be removed or altered from
any source or altered source distribution.
The Contributing Authors and Group 42, Inc. specifically permit, without
fee, and encourage the use of this source code as a component to
supporting the PNG file format in commercial products. If you use this
source code in a product, acknowledgment is not required but would be
appreciated.
A "png_get_copyright" function is available, for convenient use in "about"
boxes and the like:
printf("%s",png_get_copyright(NULL));
Also, the PNG logo (in PNG format, of course) is supplied in the
files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a
certification mark of the Open Source Initiative.
Glenn Randers-Pehrson
glennrp at users.sourceforge.net
May 9, 2015
.\" end of man page

93
png.h
View File

@ -1,7 +1,7 @@
/* png.h - header file for PNG reference library
*
* libpng version 1.2.54beta01, May 9, 2015
* libpng version 1.2.54beta01, July 13, 2015
*
* Copyright (c) 1998-2015 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@ -12,7 +12,7 @@
* Authors and maintainers:
* libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
* libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
* libpng versions 0.97, January 1998, through 1.2.54beta01, May 9, 2015: Glenn
* libpng versions 0.97, January 1998, through 1.2.54beta01, July 13, 2015: Glenn
* See also "Contributing Authors", below.
*
* Note about libpng version numbers:
@ -330,20 +330,14 @@
*
* This code is released under the libpng license.
*
* libpng versions 1.2.6, August 15, 2004, through 1.2.54beta01, May 9, 2015, are
* Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
* distributed according to the same disclaimer and license as libpng-1.2.5
* with the following individual added to the list of Contributing Authors:
*
* Cosmin Truta
*
* libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
* Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
* libpng versions 1.0.7, July 1, 2000, through 1.2.54beta01, July 13, 2015, are
* Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, and are
* distributed according to the same disclaimer and license as libpng-1.0.6
* with the following individuals added to the list of Contributing Authors:
*
* Simon-Pierre Cadieux
* Eric S. Raymond
* Cosmin Truta
* Gilles Vollant
*
* and with the following additions to the disclaimer:
@ -356,17 +350,17 @@
* the user.
*
* libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
* Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
* distributed according to the same disclaimer and license as libpng-0.96,
* with the following individuals added to the list of Contributing Authors:
* Copyright (c) 1998-2000 Glenn Randers-Pehrson, and are distributed according
* to the same disclaimer and license as libpng-0.96, with the following
* individuals added to the list of Contributing Authors:
*
* Tom Lane
* Glenn Randers-Pehrson
* Willem van Schaik
*
* libpng versions 0.89, June 1996, through 0.96, May 1997, are
* Copyright (c) 1996, 1997 Andreas Dilger
* Distributed according to the same disclaimer and license as libpng-0.88,
* Copyright (c) 1996-1997 Andreas Dilger, and are
* distributed according to the same disclaimer and license as libpng-0.88,
* with the following individuals added to the list of Contributing Authors:
*
* John Bowler
@ -377,7 +371,7 @@
* Tom Tanner
*
* libpng versions 0.5, May 1995, through 0.88, January 1996, are
* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
* Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
*
* For the purposes of this copyright and license, "Contributing Authors"
* is defined as the following set of individuals:
@ -400,13 +394,13 @@
* source code, or portions hereof, for any purpose, without fee, subject
* to the following restrictions:
*
* 1. The origin of this source code must not be misrepresented.
* 1. The origin of this source code must not be misrepresented.
*
* 2. Altered versions must be plainly marked as such and
* must not be misrepresented as being the original source.
* 2. Altered versions must be plainly marked as such and must not
* be misrepresented as being the original source.
*
* 3. This Copyright notice may not be removed or altered from
* any source or altered source distribution.
* 3. This Copyright notice may not be removed or altered from any
* source or altered source distribution.
*
* The Contributing Authors and Group 42, Inc. specifically permit, without
* fee, and encourage the use of this source code as a component to
@ -419,15 +413,16 @@
* A "png_get_copyright" function is available, for convenient use in "about"
* boxes and the like:
*
* printf("%s",png_get_copyright(NULL));
* printf("%s", png_get_copyright(NULL));
*
* Also, the PNG logo (in PNG format, of course) is supplied in the
* files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
*/
/*
* Libpng is OSI Certified Open Source Software. OSI Certified is a
* certification mark of the Open Source Initiative.
* Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
* a certification mark of the Open Source Initiative. OSI has not addressed
* the additional disclaimers inserted at version 1.0.7.
*/
/*
@ -442,7 +437,7 @@
* Y2K compliance in libpng:
* =========================
*
* May 9, 2015
* July 13, 2015
*
* Since the PNG Development group is an ad-hoc body, we can't make
* an official declaration.
@ -506,7 +501,7 @@
/* Version information for png.h - this should match the version in png.c */
#define PNG_LIBPNG_VER_STRING "1.2.54beta01"
#define PNG_HEADER_VERSION_STRING \
" libpng version 1.2.54beta01 - May 9, 2015\n"
" libpng version 1.2.54beta01 - July 13, 2015\n"
#define PNG_LIBPNG_VER_SONUM 0
#define PNG_LIBPNG_VER_DLLNUM 13
@ -1460,16 +1455,6 @@ struct png_struct_def
png_uint_16p hist PNG_DEPSTRUCT; /* histogram */
#endif
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_byte heuristic_method PNG_DEPSTRUCT; /* heuristic for row filter selection */
png_byte num_prev_filters PNG_DEPSTRUCT; /* number of weights for previous rows */
png_bytep prev_filters PNG_DEPSTRUCT; /* filter type(s) of previous row(s) */
png_uint_16p filter_weights PNG_DEPSTRUCT; /* weight(s) for previous line(s) */
png_uint_16p inv_filter_weights PNG_DEPSTRUCT; /* 1/weight(s) for previous line(s) */
png_uint_16p filter_costs PNG_DEPSTRUCT; /* relative filter calculation cost */
png_uint_16p inv_filter_costs PNG_DEPSTRUCT; /* 1/relative filter calculation cost */
#endif
#ifdef PNG_TIME_RFC1123_SUPPORTED
png_charp time_buffer PNG_DEPSTRUCT; /* String to hold RFC 1123 time text */
#endif
@ -1985,35 +1970,7 @@ extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,
#define PNG_FILTER_VALUE_PAETH 4
#define PNG_FILTER_VALUE_LAST 5
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* EXPERIMENTAL */
/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
* defines, either the default (minimum-sum-of-absolute-differences), or
* the experimental method (weighted-minimum-sum-of-absolute-differences).
*
* Weights are factors >= 1.0, indicating how important it is to keep the
* filter type consistent between rows. Larger numbers mean the current
* filter is that many times as likely to be the same as the "num_weights"
* previous filters. This is cumulative for each previous row with a weight.
* There needs to be "num_weights" values in "filter_weights", or it can be
* NULL if the weights aren't being specified. Weights have no influence on
* the selection of the first row filter. Well chosen weights can (in theory)
* improve the compression for a given image.
*
* Costs are factors >= 1.0 indicating the relative decoding costs of a
* filter type. Higher costs indicate more decoding expense, and are
* therefore less likely to be selected over a filter with lower computational
* costs. There needs to be a value in "filter_costs" for each valid filter
* type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
* setting the costs. Costs try to improve the speed of decompression without
* unduly increasing the compressed image size.
*
* A negative weight or cost indicates the default value is to be used, and
* values in the range [0.0, 1.0) indicate the value is to remain unchanged.
* The default values for both weights and costs are currently 1.0, but may
* change if good general weighting/cost heuristics can be found. If both
* the weights and costs are set to 1.0, this degenerates the WEIGHTED method
* to the UNWEIGHTED method, but with added encoding time/computation.
*/
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* DEPRECATED */
#ifdef PNG_FLOATING_POINT_SUPPORTED
extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
int heuristic_method, int num_weights, png_doublep filter_weights,
@ -2021,9 +1978,7 @@ extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
#endif
#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
/* Heuristic used for row filter selection. These defines should NOT be
* changed.
*/
/* The following are no longer used and will be removed from libpng-1.7: */
#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */

133
pngwrite.c
View File

@ -584,11 +584,6 @@ png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,
png_flush_ptr_NULL);
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
1, png_doublep_NULL, png_doublep_NULL);
#endif
#ifdef PNG_SETJMP_SUPPORTED
/* Applications that neglect to set up their own setjmp() and then
* encounter a png_error() will longjmp here. Since the jmpbuf is
@ -731,10 +726,6 @@ png_write_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
(png_uint_32)png_ptr->zbuf_size);
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
1, png_doublep_NULL, png_doublep_NULL);
#endif
}
/* Write a few rows of image data. If the image is interlaced,
@ -1150,14 +1141,6 @@ png_write_destroy(png_structp png_ptr)
png_free(png_ptr, png_ptr->time_buffer);
#endif
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_free(png_ptr, png_ptr->prev_filters);
png_free(png_ptr, png_ptr->filter_weights);
png_free(png_ptr, png_ptr->inv_filter_weights);
png_free(png_ptr, png_ptr->filter_costs);
png_free(png_ptr, png_ptr->inv_filter_costs);
#endif
#ifdef PNG_SETJMP_SUPPORTED
/* Reset structure */
png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
@ -1310,117 +1293,11 @@ png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,
int num_weights, png_doublep filter_weights,
png_doublep filter_costs)
{
int i;
png_debug(1, "in png_set_filter_heuristics");
if (png_ptr == NULL)
return;
if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)
{
png_warning(png_ptr, "Unknown filter heuristic method");
return;
}
if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT)
{
heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
}
if (num_weights < 0 || filter_weights == NULL ||
heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
{
num_weights = 0;
}
png_ptr->num_prev_filters = (png_byte)num_weights;
png_ptr->heuristic_method = (png_byte)heuristic_method;
if (num_weights > 0)
{
if (png_ptr->prev_filters == NULL)
{
png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
(png_uint_32)(png_sizeof(png_byte) * num_weights));
/* To make sure that the weighting starts out fairly */
for (i = 0; i < num_weights; i++)
{
png_ptr->prev_filters[i] = 255;
}
}
if (png_ptr->filter_weights == NULL)
{
png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
(png_uint_32)(png_sizeof(png_uint_16) * num_weights));
png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
(png_uint_32)(png_sizeof(png_uint_16) * num_weights));
for (i = 0; i < num_weights; i++)
{
png_ptr->inv_filter_weights[i] =
png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
}
}
for (i = 0; i < num_weights; i++)
{
if (filter_weights[i] < 0.0)
{
png_ptr->inv_filter_weights[i] =
png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
}
else
{
png_ptr->inv_filter_weights[i] =
(png_uint_16)((double)PNG_WEIGHT_FACTOR*filter_weights[i]+0.5);
png_ptr->filter_weights[i] =
(png_uint_16)((double)PNG_WEIGHT_FACTOR/filter_weights[i]+0.5);
}
}
}
/* If, in the future, there are other filter methods, this would
* need to be based on png_ptr->filter.
*/
if (png_ptr->filter_costs == NULL)
{
png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
(png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
(png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
{
png_ptr->inv_filter_costs[i] =
png_ptr->filter_costs[i] = PNG_COST_FACTOR;
}
}
/* Here is where we set the relative costs of the different filters. We
* should take the desired compression level into account when setting
* the costs, so that Paeth, for instance, has a high relative cost at low
* compression levels, while it has a lower relative cost at higher
* compression settings. The filter types are in order of increasing
* relative cost, so it would be possible to do this with an algorithm.
*/
for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
{
if (filter_costs == NULL || filter_costs[i] < 0.0)
{
png_ptr->inv_filter_costs[i] =
png_ptr->filter_costs[i] = PNG_COST_FACTOR;
}
else if (filter_costs[i] >= 1.0)
{
png_ptr->inv_filter_costs[i] =
(png_uint_16)((double)PNG_COST_FACTOR / filter_costs[i] + 0.5);
png_ptr->filter_costs[i] =
(png_uint_16)((double)PNG_COST_FACTOR * filter_costs[i] + 0.5);
}
}
PNG_UNUSED(png_ptr)
PNG_UNUSED(heuristic_method)
PNG_UNUSED(num_weights)
PNG_UNUSED(filter_weights)
PNG_UNUSED(filter_costs)
}
#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */

314
pngwutil.c
View File

@ -2156,20 +2156,9 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
png_uint_32 mins, bpp;
png_byte filter_to_do = png_ptr->do_filter;
png_uint_32 row_bytes = row_info->rowbytes;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
int num_p_filters = (int)png_ptr->num_prev_filters;
#endif
png_debug(1, "in png_write_find_filter");
#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
{
/* These will never be selected so we need not test them. */
filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
}
#endif
/* Find out how many bytes offset each pixel is */
bpp = (row_info->pixel_depth + 7) >> 3;
@ -2219,41 +2208,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
sum += (v < 128) ? v : 256 - v;
}
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
png_uint_32 sumhi, sumlo;
int j;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
/* Reduce the sum if we match any of the previous rows */
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
{
sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
/* Factor in the cost of this filter (this is here for completeness,
* but it makes no sense to have a "cost" for the NONE filter, as
* it has the minimum possible computational cost - none).
*/
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
PNG_COST_SHIFT;
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
PNG_COST_SHIFT;
if (sumhi > PNG_HIMASK)
sum = PNG_MAXSUM;
else
sum = (sumhi << PNG_HISHIFT) + sumlo;
}
#endif
mins = sum;
}
@ -2283,41 +2237,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
png_uint_32 i;
int v;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
/* We temporarily increase the "minimum sum" by the factor we
* would reduce the sum of this filter, so that we can do the
* early exit comparison without scaling the sum each time.
*/
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
{
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
PNG_COST_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
PNG_COST_SHIFT;
if (lmhi > PNG_HIMASK)
lmins = PNG_MAXSUM;
else
lmins = (lmhi << PNG_HISHIFT) + lmlo;
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
i++, rp++, dp++)
{
@ -2336,37 +2255,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
break;
}
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
{
sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
PNG_COST_SHIFT;
sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
PNG_COST_SHIFT;
if (sumhi > PNG_HIMASK)
sum = PNG_MAXSUM;
else
sum = (sumhi << PNG_HISHIFT) + sumlo;
}
#endif
if (sum < mins)
{
mins = sum;
@ -2396,38 +2284,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
png_uint_32 i;
int v;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
{
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
PNG_COST_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
PNG_COST_SHIFT;
if (lmhi > PNG_HIMASK)
lmins = PNG_MAXSUM;
else
lmins = (lmhi << PNG_HISHIFT) + lmlo;
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
pp = prev_row + 1; i < row_bytes; i++)
{
@ -2439,37 +2295,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
break;
}
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
{
sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
PNG_COST_SHIFT;
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
PNG_COST_SHIFT;
if (sumhi > PNG_HIMASK)
sum = PNG_MAXSUM;
else
sum = (sumhi << PNG_HISHIFT) + sumlo;
}
#endif
if (sum < mins)
{
mins = sum;
@ -2502,37 +2327,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
png_uint_32 i;
int v;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
{
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
PNG_COST_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
PNG_COST_SHIFT;
if (lmhi > PNG_HIMASK)
lmins = PNG_MAXSUM;
else
lmins = (lmhi << PNG_HISHIFT) + lmlo;
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
pp = prev_row + 1; i < bpp; i++)
{
@ -2551,37 +2345,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
break;
}
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
{
sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
PNG_COST_SHIFT;
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
PNG_COST_SHIFT;
if (sumhi > PNG_HIMASK)
sum = PNG_MAXSUM;
else
sum = (sumhi << PNG_HISHIFT) + sumlo;
}
#endif
if (sum < mins)
{
mins = sum;
@ -2635,37 +2398,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
png_uint_32 i;
int v;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
{
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
PNG_COST_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
PNG_COST_SHIFT;
if (lmhi > PNG_HIMASK)
lmins = PNG_MAXSUM;
else
lmins = (lmhi << PNG_HISHIFT) + lmlo;
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
pp = prev_row + 1; i < bpp; i++)
{
@ -2716,37 +2448,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
break;
}
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < num_p_filters; j++)
{
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
{
sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
PNG_COST_SHIFT;
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
PNG_COST_SHIFT;
if (sumhi > PNG_HIMASK)
sum = PNG_MAXSUM;
else
sum = (sumhi << PNG_HISHIFT) + sumlo;
}
#endif
if (sum < mins)
{
best_row = png_ptr->paeth_row;
@ -2756,21 +2457,6 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
/* Do the actual writing of the filtered row data from the chosen filter. */
png_write_filtered_row(png_ptr, best_row);
#ifdef PNG_WRITE_FILTER_SUPPORTED
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
/* Save the type of filter we picked this time for future calculations */
if (png_ptr->num_prev_filters > 0)
{
int j;
for (j = 1; j < num_p_filters; j++)
{
png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
}
png_ptr->prev_filters[j] = best_row[0];
}
#endif
#endif /* PNG_WRITE_FILTER_SUPPORTED */
}