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Imported from libpng-1.2.0beta1.tar

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Glenn Randers-Pehrson
2001-05-06 05:34:26 -05:00
parent e68f5a361b
commit 1fd5fb33c2
56 changed files with 1093 additions and 826 deletions
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libpng.3
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@@ -1,6 +1,6 @@
.TH LIBPNG 3 "May 14, 2001"
.TH LIBPNG 3 "May 6, 2001"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
libpng \- Portable Network Graphics (PNG) Reference Library 1.2.0beta1
.SH SYNOPSIS
\fI\fB
@@ -100,6 +100,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
\fI\fB
\fBpng_uint_32 png_get_asm_flags (png_structp \fIpng_ptr\fP\fB);\fP
\fI\fB
\fBpng_byte png_get_bit_depth (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
\fI\fB
@@ -192,6 +196,18 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
\fI\fB
\fBpng_byte png_get_mmx_bitdepth_threshold (png_structp \fIpng_ptr\fP\fB);\fP
\fI\fB
\fBpng_uint_32 png_get_mmx_flagmask (int \fP\fIflag_select\fP\fB, int \fI*compilerID\fP\fB);\fP
\fI\fB
\fBpng_uint_32 png_get_mmx_rowbytes_threshold (png_structp \fIpng_ptr\fP\fB);\fP
\fI\fB
\fBpng_uint_32 png_get_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP
\fI\fB
@@ -334,6 +350,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
\fI\fB
\fBint png_mmx_support \fI(void\fP\fB);\fP
\fI\fB
\fBvoid png_permit_empty_plte (png_structp \fP\fIpng_ptr\fP\fB, int \fIempty_plte_permitted\fP\fB);\fP
\fI\fB
@@ -384,6 +404,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
\fI\fB
\fBpng_set_asm_flags (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIasm_flags\fP\fB);\fP
\fI\fB
\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
\fI\fB
@@ -512,6 +536,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
\fI\fB
\fBpng_set_mmx_thresholds (png_structp \fP\fIpng_ptr\fP\fB, png_byte \fP\fImmx_bitdepth_threshold\fP\fB, png_uint_32 \fImmx_rowbytes_threshold\fP\fB);\fP
\fI\fB
\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP
\fI\fB
@@ -604,6 +632,12 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.12beta1
\fI\fB
\fBvoid png_set_strip_error_numbers (png_structp \fIpng_ptr,
\fBpng_uint_32 \fIstrip_mode\fP\fB);\fP
\fI\fB
\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP
\fI\fB
@@ -747,7 +781,7 @@ 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 1.0.12beta1 - May 14, 2001
libpng version 1.2.0beta1 - May 6, 2001
Updated and distributed by Glenn Randers-Pehrson
<randeg@alum.rpi.edu>
Copyright (c) 1998-2001 Glenn Randers-Pehrson
@@ -2143,7 +2177,6 @@ png_infop info_ptr;
/* This function is called when each row of image
data is complete */
void
row_callback(png_structp png_ptr, png_bytep new_row,
png_uint_32 row_num, int pass)
@@ -3392,8 +3425,106 @@ When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
having level = 0 will be printed. There aren't any such statements in
this version of libpng, but if you insert some they will be printed.
.SH VI. Runtime optimization
.SH VI. MNG support
A new feature in libpng 1.2.0 is the ability to dynamically switch between
standard and optimized versions of some routines. Currently these are
limited to three computationally intensive tasks when reading PNG files:
decoding row filters, expanding interlacing, and combining interlaced or
transparent row data with previous row data. Currently the optimized
versions are available only for x86 (Intel, AMD, etc.) platforms with
MMX support, though this may change in future versions. (For example,
the non-MMX assembler optimizations for zlib might become similarly
runtime-selectable in future releases, in which case libpng could be
extended to support them. Alternatively, the compile-time choice of
floating-point versus integer routines for gamma correction might become
runtime-selectable.)
Because such optimizations tend to be very platform- and compiler-dependent,
both in how they are written and in how they perform, the new runtime code
in libpng has been written to allow programs to query, enable, and disable
either specific optimizations or all such optimizations. For example, to
enable all possible optimizations (bearing in mind that some "optimizations"
may actually run more slowly in rare cases):
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
png_uint_32 mask, flags;
flags = png_get_asm_flags(png_ptr);
mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
png_set_asm_flags(png_ptr, flags | mask);
#endif
To enable only optimizations relevant to reading PNGs, use PNG_SELECT_READ
by itself when calling png_get_asm_flagmask(); similarly for optimizing
only writing. To disable all optimizations:
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
flags = png_get_asm_flags(png_ptr);
mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
png_set_asm_flags(png_ptr, flags & ~mask);
#endif
To enable or disable only MMX-related features, use png_get_mmx_flagmask()
in place of png_get_asm_flagmask(). The mmx version takes one additional
parameter:
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
int selection = PNG_SELECT_READ | PNG_SELECT_WRITE;
int compilerID;
mask = png_get_mmx_flagmask(selection, &compilerID);
#endif
On return, compilerID will indicate which version of the MMX assembler
optimizations was compiled. Currently two flavors exist: Microsoft
Visual C++ (compilerID == 1) and GNU C (a.k.a. gcc/gas, compilerID == 2).
On non-x86 platforms or on systems compiled without MMX optimizations, a
value of -1 is used.
Note that both png_get_asm_flagmask() and png_get_mmx_flagmask() return
all valid, settable optimization bits for the version of the library that's
currently in use. In the case of shared (dynamically linked) libraries,
this may include optimizations that did not exist at the time the code was
written and compiled. It is also possible, of course, to enable only known,
specific optimizations; for example:
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
flags = PNG_ASM_FLAG_MMX_READ_COMBINE_ROW \
| PNG_ASM_FLAG_MMX_READ_INTERLACE \
| PNG_ASM_FLAG_MMX_READ_FILTER_SUB \
| PNG_ASM_FLAG_MMX_READ_FILTER_UP \
| PNG_ASM_FLAG_MMX_READ_FILTER_AVG \
| PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
png_set_asm_flags(png_ptr, flags);
#endif
This method would enable only the MMX read-optimizations available at the
time of libpng 1.2.0's release, regardless of whether a later version of
the DLL were actually being used. (Also note that these functions did not
exist in versions older than 1.2.0, so any attempt to run a dynamically
linked app on such an older version would fail.)
To determine whether the processor supports MMX instructions at all, use
the png_mmx_support() function:
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200)
mmxsupport = png_mmx_support();
#endif
It returns -1 if MMX support is not compiled into libpng, 0 if MMX code
is compiled but MMX is not supported by the processor, or 1 if MMX support
is fully available. Note that png_mmx_support(), png_get_mmx_flagmask(),
and png_get_asm_flagmask() all may be called without allocating and ini-
tializing any PNG structures (for example, as part of a usage screen or
"about" box).
For more extensive examples of runtime querying, enabling and disabling
of optimized features, see contrib/gregbook/readpng2.c in the libpng
source-code distribution.
.SH VII. MNG support
The MNG specification (available at http://www.libpng.org/pub/mng) allows
certain extensions to PNG for PNG images that are embedded in MNG datastreams.
@@ -3418,7 +3549,7 @@ or any other MNG chunks; your application must provide its own support for
them. You may wish to consider using libmng (available at
http://www.libmng.com) instead.
.SH VII. Changes to Libpng from version 0.88
.SH VIII. Changes to Libpng from version 0.88
It should be noted that versions of libpng later than 0.96 are not
distributed by the original libpng author, Guy Schalnat, nor by
@@ -3428,7 +3559,7 @@ of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are
still alive and well, but they have moved on to other things.
The old libpng functions png_read_init(), png_write_init(),
png_info_init(), png_read_destroy(), and png_write_destroy() have been
png_info_init(), png_read_destroy(), and png_write_destory() have been
moved to PNG_INTERNAL in version 0.95 to discourage their use. These
functions will be removed from libpng version 2.0.0.
@@ -3467,15 +3598,15 @@ application:
png_uint_32 application_vn = PNG_LIBPNG_VER;
.SH VIII. Y2K Compliance in libpng
.SH IX. Y2K Compliance in libpng
May 14, 2001
May 6, 2001
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.
This is your unofficial assurance that libpng from version 0.71 and
upward through 1.0.12beta1 are Y2K compliant. It is my belief that earlier
upward through 1.2.0beta1 are Y2K compliant. It is my belief that earlier
versions were also Y2K compliant.
Libpng only has three year fields. One is a 2-byte unsigned integer that
@@ -3587,7 +3718,8 @@ the first widely used release:
1.0.11beta1-3 1 10011 2.1.0.11beta1-3
1.0.11rc1 1 10011 2.1.0.11rc1
1.0.11 1 10011 2.1.0.11
1.0.12beta1 1 10012 2.1.0.12beta1
1.1.0a-f 1 10100 2.1.1.0 abandoned
1.2.0beta1 2 10200 2.1.2.0beta1
Henceforth the source version will match the shared-library minor
and patch numbers; the shared-library major version number will be
@@ -3645,7 +3777,7 @@ possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation.
Libpng version 1.0.12beta1 - May 14, 2001:
Libpng version 1.2.0beta1 - May 6, 2001:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Currently maintained by Glenn Randers-Pehrson (randeg@alum.rpi.edu).
@@ -3662,7 +3794,7 @@ included in the libpng distribution, the latter shall prevail.)
If you modify libpng you may insert additional notices immediately following
this sentence.
libpng versions 1.0.7, July 1, 2000, through 1.0.12beta1, May 14, 2001, are
libpng versions 1.0.7, July 1, 2000, through 1.2.0beta1, May 6, 2001, are
Copyright (c) 2000-2001 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
@@ -3754,7 +3886,7 @@ certification mark of the Open Source Initiative.
Glenn Randers-Pehrson
randeg@alum.rpi.edu
May 14, 2001
May 6, 2001
.\" end of man page