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Imported from libpng-1.0.9beta2.tar

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Glenn Randers-Pehrson
2000-11-18 18:19:14 -06:00
parent fbbb5ecb52
commit f5ed0e130c
70 changed files with 1269 additions and 1711 deletions
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libpng.3
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@@ -1,6 +1,6 @@
.TH LIBPNG 3 "January 16, 2001"
.TH LIBPNG 3 "November 19, 2000"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta10
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta2
.SH SYNOPSIS
\fI\fB
@@ -100,10 +100,6 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta10
\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
@@ -338,10 +334,6 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta10
\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
@@ -392,10 +384,6 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.9beta10
\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
@@ -759,7 +747,7 @@ 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 1.0.9beta10 - January 16, 2001
libpng version 1.0.9beta2 - November 19, 2000
Updated and distributed by Glenn Randers-Pehrson
<randeg@alum.rpi.edu>
Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
@@ -826,7 +814,7 @@ majority of the needs of its users.
Libpng uses zlib for its compression and decompression of PNG files.
Further information about zlib, and the latest version of zlib, can
be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
be found at the zlib home page, <ftp://ftp.freesoftware.com/pub/infozip/zlib/>.
The zlib compression utility is a general purpose utility that is
useful for more than PNG files, and can be used without libpng.
See the documentation delivered with zlib for more details.
@@ -1130,7 +1118,7 @@ row_pointers prior to calling png_read_png() with
row_pointers = png_malloc(png_ptr, height*sizeof(png_bytep));
for (int i=0; i<height, i++)
row_pointers[i]=png_malloc(png_ptr, width*pixel_size);
png_set_rows(png_ptr, info_ptr, &row_pointers);
png_set_rows(png_ptr, info_ptr, &row_pointers);
Alternatively you could allocate your image in one big block and define
row_pointers[i] to point into the proper places in your block.
@@ -1159,7 +1147,7 @@ in until png_read_end() has read the chunk data following the image.
png_get_IHDR(png_ptr, info_ptr, &width, &height,
&bit_depth, &color_type, &interlace_type,
&compression_type, &filter_method);
&compression_type, &filter_type);
width - holds the width of the image
in pixels (up to 2^31).
@@ -1187,18 +1175,15 @@ in until png_read_end() has read the chunk data following the image.
PNG_COLOR_MASK_COLOR
PNG_COLOR_MASK_ALPHA
filter_method - (must be PNG_FILTER_TYPE_BASE
for PNG 1.0, and can also be
PNG_INTRAPIXEL_DIFFERENCING if
the PNG datastream is embedded in
a MNG-1.0 datastream)
filter_type - (must be PNG_FILTER_TYPE_BASE
for PNG 1.0)
compression_type - (must be PNG_COMPRESSION_TYPE_BASE
for PNG 1.0)
interlace_type - (PNG_INTERLACE_NONE or
PNG_INTERLACE_ADAM7)
Any or all of interlace_type, compression_type, of
filter_method can be NULL if you are
not interested in their values.
filter_type can be NULL if you are not
interested in their values.
channels = png_get_channels(png_ptr, info_ptr);
channels - number of channels of info for the
@@ -1228,7 +1213,7 @@ in until png_read_end() has read the chunk data following the image.
info_ptr);
color_type = png_get_color_type(png_ptr,
info_ptr);
filter_method = png_get_filter_type(png_ptr,
filter_type = png_get_filter_type(png_ptr,
info_ptr);
compression_type = png_get_compression_type(png_ptr,
info_ptr);
@@ -1326,7 +1311,7 @@ into the info_ptr is returned for any complex types.
(empty string for unknown).
num_text - number of comments (same as num_comments;
you can put NULL here to avoid the duplication)
Note while png_set_text() will accept text, language, and
Note while png_set_text() will accept text, language, and
translated keywords that can be NULL pointers, the structure
returned by png_get_text will always contain regular
zero-terminated C strings. They might be empty strings but
@@ -1721,7 +1706,7 @@ histogram, it may not do as good a job.
if (png_get_valid(png_ptr, info_ptr,
PNG_INFO_PLTE))
{
png_uint_16p histogram;
png_color_16p histogram;
png_get_hIST(png_ptr, info_ptr,
&histogram);
@@ -2009,7 +1994,7 @@ application instead of by libpng, you can use
png_set_invalid(png_ptr, info_ptr, mask);
mask - identifies the chunks to be made invalid,
containing the logical OR of one or
more of
more of
PNG_INFO_gAMA, PNG_INFO_sBIT,
PNG_INFO_cHRM, PNG_INFO_PLTE,
PNG_INFO_tRNS, PNG_INFO_bKGD,
@@ -2301,11 +2286,10 @@ maximum possible compression at the expense of slower writing. If you
have no special needs in this area, let the library do what it wants by
not calling this function at all, as it has been tuned to deliver a good
speed/compression ratio. The second parameter to png_set_filter() is
the filter method, for which the only valid values are 0 (as of the
July 1999 PNG specification, version 1.2) or 64 (if you are writing
a PNG datastream that is to be embedded in a MNG datastream). The third
parameter is a flag that indicates which filter type(s) are to be tested
for each scanline. See the PNG specification for details on the specific filter
the filter method, for which the only valid value is '0' (as of the
July 1999 PNG specification, version 1.2). The third parameter is a
flag that indicates which filter type(s) are to be tested for each
scanline. See the PNG specification for details on the specific filter
types.
@@ -2326,9 +2310,6 @@ it should start out with all of the filters (to ensure that the previous
row of pixels will be stored in case it's needed later), and then add
and remove them after the start of compression.
If you are writing a PNG datastream that is to be embedded in a MNG
datastream, the second parameter can be either 0 or 64.
The png_set_compression_*() functions interface to the zlib compression
library, and should mostly be ignored unless you really know what you are
doing. The only generally useful call is png_set_compression_level()
@@ -2367,7 +2348,7 @@ Some of the more important parts of the png_info are:
png_set_IHDR(png_ptr, info_ptr, width, height,
bit_depth, color_type, interlace_type,
compression_type, filter_method)
compression_type, filter_type)
width - holds the width of the image
in pixels (up to 2^31).
height - holds the height of the image
@@ -2399,11 +2380,7 @@ Some of the more important parts of the png_info are:
PNG_INTERLACE_ADAM7
compression_type - (must be
PNG_COMPRESSION_TYPE_DEFAULT)
filter_method - (must be PNG_FILTER_TYPE_DEFAULT
or, if you are writing a PNG to
be embedded in a MNG datastream,
can also be
PNG_INTRAPIXEL_DIFFERENCING)
filter_type - (must be PNG_FILTER_TYPE_DEFAULT)
png_set_PLTE(png_ptr, info_ptr, palette,
num_palette);
@@ -3001,22 +2978,13 @@ For a more compact example of writing a PNG image, see the file example.c.
.SH V. Modifying/Customizing libpng:
There are three issues here. The first is changing how libpng does
There are two issues here. The first is changing how libpng does
standard things like memory allocation, input/output, and error handling.
The second deals with more complicated things like adding new chunks,
adding new transformations, and generally changing how libpng works.
Both of those are compile-time issues; that is, they are generally
determined at the time the code is written, and there is rarely a need
to provide the user with a means of changing them. The third is a
run-time issue: choosing between and/or tuning one or more alternate
versions of computationally intensive routines; specifically, optimized
assembly-language (and therefore compiler- and platform-dependent)
versions.
Memory allocation, input/output, and error handling
All of the memory allocation, input/output, and error handling in libpng
goes through callbacks that are user-settable. The default routines are
goes through callbacks that are user settable. The default routines are
in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change
these functions, call the appropriate png_set_*_fn() function.
@@ -3249,10 +3217,6 @@ structures appropriately for all of the filter types.
png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
filters);
The second parameter can also be PNG_INTRAPIXEL_DIFFERENCING
if you are writing a PNG to be embedded in a MNG
datastream. This parameter must be the 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 two ways - by telling it how
@@ -3364,33 +3328,7 @@ 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. 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.
Libpng can support some of these extensions. To enable them, use the
png_permit_mng_features() function:
feature_set = png_permit_mng_features(png_ptr, mask)
mask is a png_uint_32 containing the logical OR of the
features you want to enable. These include
PNG_FLAG_MNG_EMPTY_PLTE
PNG_FLAG_MNG_FILTER_64
PNG_ALL_MNG_FEATURES
feature_set is a png_32_uint that is the logical AND of
your mask with the set of MNG features that is
supported by the version of libpng that you are using.
It is an error to use this function when reading or writing a standalone
PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped
in a MNG datastream. As a minimum, it must have the MNG 8-byte signature
and the MHDR and MEND chunks. Libpng does not provide support for these
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 VI. 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
@@ -3439,15 +3377,15 @@ application:
png_uint_32 application_vn = PNG_LIBPNG_VER;
.SH VIII. Y2K Compliance in libpng
.SH VII. Y2K Compliance in libpng
January 16, 2001
November 19, 2000
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 1.0.9beta10 are Y2K compliant. It is my belief that earlier
upward through 1.0.9beta2 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
@@ -3588,7 +3526,7 @@ possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation.
Libpng version 1.0.9beta10 - January 16, 2001:
Libpng version 1.0.9beta2 - November 19, 2000:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Currently maintained by Glenn Randers-Pehrson (randeg@alum.rpi.edu).
@@ -3605,7 +3543,7 @@ 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 1.0.9beta10, January 16, 2001, are
libpng versions 1.0.7, July 1, 2000, through 1.0.9beta2, November 19, 2000, are
Copyright (c) 2000 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
@@ -3696,7 +3634,7 @@ certification mark of the Open Source Initiative.
Glenn Randers-Pehrson
randeg@alum.rpi.edu
January 16, 2001
November 19, 2000
.\" end of man page