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png.h
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/* png.h - header file for PNG reference library
*
* libpng version 1.6.47.git
*
* Copyright (c) 2018-2025 Cosmin Truta
* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
* Copyright (c) 1996-1997 Andreas Dilger
* Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
*
* This code is released under the libpng license. (See LICENSE, below.)
*
* Authors and maintainers:
* libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
* libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
* libpng versions 0.97, January 1998, through 1.6.35, July 2018:
* Glenn Randers-Pehrson
* libpng versions 1.6.36, December 2018, through 1.6.46, January 2025:
* Cosmin Truta
* See also "Contributing Authors", below.
*/
/*
* COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
* =========================================
*
* PNG Reference Library License version 2
* ---------------------------------------
*
* * Copyright (c) 1995-2025 The PNG Reference Library Authors.
* * Copyright (c) 2018-2025 Cosmin Truta.
* * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
* * Copyright (c) 1996-1997 Andreas Dilger.
* * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
*
* The software is supplied "as is", without warranty of any kind,
* express or implied, including, without limitation, the warranties
* of merchantability, fitness for a particular purpose, title, and
* non-infringement. In no event shall the Copyright owners, or
* anyone distributing the software, be liable for any damages or
* other liability, whether in contract, tort or otherwise, arising
* from, out of, or in connection with the software, or the use or
* other dealings in the software, even if advised of the possibility
* of such damage.
*
* Permission is hereby granted to use, copy, modify, and distribute
* this software, or portions hereof, for any purpose, without fee,
* subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you
* must not claim that you wrote the original software. If you
* use this software in a product, an acknowledgment in the product
* documentation would be appreciated, but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must
* not be misrepresented as being the original software.
*
* 3. This Copyright notice may not be removed or altered from any
* source or altered source distribution.
*
*
* PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
* -----------------------------------------------------------------------
*
* libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
* Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
* derived from libpng-1.0.6, 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
* Mans Rullgard
* Cosmin Truta
* Gilles Vollant
* James Yu
* Mandar Sahastrabuddhe
* Google Inc.
* Vadim Barkov
*
* 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.
*
* Some files in the "contrib" directory and some configure-generated
* files that are distributed with libpng have other copyright owners, and
* are released under other open source licenses.
*
* libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
* Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
* libpng-0.96, 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, are derived from libpng-0.88,
* 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
* Kevin Bracey
* Sam Bushell
* Magnus Holmgren
* Greg Roelofs
* Tom Tanner
*
* Some files in the "scripts" directory have other copyright owners,
* but are released under this license.
*
* 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.
*
* END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
*
* TRADEMARK
* =========
*
* The name "libpng" has not been registered by the Copyright owners
* as a trademark in any jurisdiction. However, because libpng has
* been distributed and maintained world-wide, continually since 1995,
* the Copyright owners claim "common-law trademark protection" in any
* jurisdiction where common-law trademark is recognized.
*/
/*
* 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).
*/
/*
* The contributing authors would like to thank all those who helped
* with testing, bug fixes, and patience. This wouldn't have been
* possible without all of you.
*
* Thanks to Frank J. T. Wojcik for helping with the documentation.
*/
/* Note about libpng version numbers:
*
* Due to various miscommunications, unforeseen code incompatibilities
* and occasional factors outside the authors' control, version numbering
* on the library has not always been consistent and straightforward.
* The following table summarizes matters since version 0.89c, which was
* the first widely used release:
*
* source png.h png.h shared-lib
* version string int version
* ------- ------ ----- ----------
* 0.89c "1.0 beta 3" 0.89 89 1.0.89
* 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
* 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
* 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
* 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
* 0.97c 0.97 97 2.0.97
* 0.98 0.98 98 2.0.98
* 0.99 0.99 98 2.0.99
* 0.99a-m 0.99 99 2.0.99
* 1.00 1.00 100 2.1.0 [100 should be 10000]
* 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
* 1.0.1 png.h string is 10001 2.1.0
* 1.0.1a-e identical to the 10002 from here on, the shared library
* 1.0.2 source version) 10002 is 2.V where V is the source code
* 1.0.2a-b 10003 version, except as noted.
* 1.0.3 10003
* 1.0.3a-d 10004
* 1.0.4 10004
* 1.0.4a-f 10005
* 1.0.5 (+ 2 patches) 10005
* 1.0.5a-d 10006
* 1.0.5e-r 10100 (not source compatible)
* 1.0.5s-v 10006 (not binary compatible)
* 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
* 1.0.6d-f 10007 (still binary incompatible)
* 1.0.6g 10007
* 1.0.6h 10007 10.6h (testing xy.z so-numbering)
* 1.0.6i 10007 10.6i
* 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
* 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
* 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
* 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
* 1.0.7 1 10007 (still compatible)
* ...
* 1.0.69 10 10069 10.so.0.69[.0]
* ...
* 1.2.59 13 10259 12.so.0.59[.0]
* ...
* 1.4.20 14 10420 14.so.0.20[.0]
* ...
* 1.5.30 15 10530 15.so.15.30[.0]
* ...
* 1.6.46 16 10646 16.so.16.46[.0]
*
* Henceforth the source version will match the shared-library major and
* minor numbers; the shared-library major version number will be used for
* changes in backward compatibility, as it is intended.
* The PNG_LIBPNG_VER macro, which is not used within libpng but is
* available for applications, is an unsigned integer of the form XYYZZ
* corresponding to the source version X.Y.Z (leading zeros in Y and Z).
* Beta versions were given the previous public release number plus a
* letter, until version 1.0.6j; from then on they were given the upcoming
* public release number plus "betaNN" or "rcNN".
*
* Binary incompatibility exists only when applications make direct access
* to the info_ptr or png_ptr members through png.h, and the compiled
* application is loaded with a different version of the library.
*
* See libpng.txt or libpng.3 for more information. The PNG specification
* is available as a W3C Recommendation and as an ISO/IEC Standard; see
* <https://www.w3.org/TR/2003/REC-PNG-20031110/>
*/
#ifndef PNG_H
#define PNG_H
#ifdef _DEBUG
#define PNG_DEBUG 1
#endif
/* This is not the place to learn how to use libpng. The file libpng-manual.txt
* describes how to use libpng, and the file example.c summarizes it
* with some code on which to build. This file is useful for looking
* at the actual function definitions and structure components. If that
* file has been stripped from your copy of libpng, you can find it at
* <http://www.libpng.org/pub/png/libpng-manual.txt>
*
* If you just need to read a PNG file and don't want to read the documentation
* skip to the end of this file and read the section entitled 'simplified API'.
*/
/* Version information for png.h - this should match the version in png.c */
#define PNG_LIBPNG_VER_STRING "1.6.47.git"
#define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
/* The versions of shared library builds should stay in sync, going forward */
#define PNG_LIBPNG_VER_SHAREDLIB 16
#define PNG_LIBPNG_VER_SONUM PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
#define PNG_LIBPNG_VER_DLLNUM PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
#define PNG_LIBPNG_VER_MAJOR 1
#define PNG_LIBPNG_VER_MINOR 6
#define PNG_LIBPNG_VER_RELEASE 47
/* This should be zero for a public release, or non-zero for a
* development version.
*/
#define PNG_LIBPNG_VER_BUILD 1
/* Release Status */
#define PNG_LIBPNG_BUILD_ALPHA 1
#define PNG_LIBPNG_BUILD_BETA 2
#define PNG_LIBPNG_BUILD_RC 3
#define PNG_LIBPNG_BUILD_STABLE 4
#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
/* Release-Specific Flags */
#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
PNG_LIBPNG_BUILD_STABLE only */
#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
PNG_LIBPNG_BUILD_SPECIAL */
#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
PNG_LIBPNG_BUILD_PRIVATE */
#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
/* Careful here. At one time, Guy wanted to use 082, but that
* would be octal. We must not include leading zeros.
* Versions 0.7 through 1.0.0 were in the range 0 to 100 here
* (only version 1.0.0 was mis-numbered 100 instead of 10000).
* From version 1.0.1 it is:
* XXYYZZ, where XX=major, YY=minor, ZZ=release
*/
#define PNG_LIBPNG_VER 10647 /* 1.6.47.git */
/* Library configuration: these options cannot be changed after
* the library has been built.
*/
#ifndef PNGLCONF_H
/* If pnglibconf.h is missing, you can
* copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
*/
# include "pnglibconf.h"
#endif
#ifndef PNG_VERSION_INFO_ONLY
/* Machine specific configuration. */
# include "pngconf.h"
#endif
/*
* Added at libpng-1.2.8
*
* Ref MSDN: Private as priority over Special
* VS_FF_PRIVATEBUILD File *was not* built using standard release
* procedures. If this value is given, the StringFileInfo block must
* contain a PrivateBuild string.
*
* VS_FF_SPECIALBUILD File *was* built by the original company using
* standard release procedures but is a variation of the standard
* file of the same version number. If this value is given, the
* StringFileInfo block must contain a SpecialBuild string.
*/
#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
# define PNG_LIBPNG_BUILD_TYPE \
(PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
#else
# ifdef PNG_LIBPNG_SPECIALBUILD
# define PNG_LIBPNG_BUILD_TYPE \
(PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
# else
# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
# endif
#endif
#ifndef PNG_VERSION_INFO_ONLY
/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/* Version information for C files, stored in png.c. This had better match
* the version above.
*/
#define png_libpng_ver png_get_header_ver(NULL)
/* This file is arranged in several sections:
*
* 1. [omitted]
* 2. Any configuration options that can be specified by for the application
* code when it is built. (Build time configuration is in pnglibconf.h)
* 3. Type definitions (base types are defined in pngconf.h), structure
* definitions.
* 4. Exported library functions.
* 5. Simplified API.
* 6. Implementation options.
*
* The library source code has additional files (principally pngpriv.h) that
* allow configuration of the library.
*/
/* Section 1: [omitted] */
/* Section 2: run time configuration
* See pnglibconf.h for build time configuration
*
* Run time configuration allows the application to choose between
* implementations of certain arithmetic APIs. The default is set
* at build time and recorded in pnglibconf.h, but it is safe to
* override these (and only these) settings. Note that this won't
* change what the library does, only application code, and the
* settings can (and probably should) be made on a per-file basis
* by setting the #defines before including png.h
*
* Use macros to read integers from PNG data or use the exported
* functions?
* PNG_USE_READ_MACROS: use the macros (see below) Note that
* the macros evaluate their argument multiple times.
* PNG_NO_USE_READ_MACROS: call the relevant library function.
*
* Use the alternative algorithm for compositing alpha samples that
* does not use division?
* PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
* algorithm.
* PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
*
* How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
* false?
* PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
* APIs to png_warning.
* Otherwise the calls are mapped to png_error.
*/
/* Section 3: type definitions, including structures and compile time
* constants.
* See pngconf.h for base types that vary by machine/system
*/
/* This triggers a compiler error in png.c, if png.c and png.h
* do not agree upon the version number.
*/
typedef char* png_libpng_version_1_6_47_git;
/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
*
* png_struct is the cache of information used while reading or writing a single
* PNG file. One of these is always required, although the simplified API
* (below) hides the creation and destruction of it.
*/
typedef struct png_struct_def png_struct;
typedef const png_struct * png_const_structp;
typedef png_struct * png_structp;
typedef png_struct * * png_structpp;
/* png_info contains information read from or to be written to a PNG file. One
* or more of these must exist while reading or creating a PNG file. The
* information is not used by libpng during read but is used to control what
* gets written when a PNG file is created. "png_get_" function calls read
* information during read and "png_set_" functions calls write information
* when creating a PNG.
* been moved into a separate header file that is not accessible to
* applications. Read libpng-manual.txt or libpng.3 for more info.
*/
typedef struct png_info_def png_info;
typedef png_info * png_infop;
typedef const png_info * png_const_infop;
typedef png_info * * png_infopp;
/* Types with names ending 'p' are pointer types. The corresponding types with
* names ending 'rp' are identical pointer types except that the pointer is
* marked 'restrict', which means that it is the only pointer to the object
* passed to the function. Applications should not use the 'restrict' types;
* it is always valid to pass 'p' to a pointer with a function argument of the
* corresponding 'rp' type. Different compilers have different rules with
* regard to type matching in the presence of 'restrict'. For backward
* compatibility libpng callbacks never have 'restrict' in their parameters and,
* consequentially, writing portable application code is extremely difficult if
* an attempt is made to use 'restrict'.
*/
typedef png_struct * PNG_RESTRICT png_structrp;
typedef const png_struct * PNG_RESTRICT png_const_structrp;
typedef png_info * PNG_RESTRICT png_inforp;
typedef const png_info * PNG_RESTRICT png_const_inforp;
/* Three color definitions. The order of the red, green, and blue, (and the
* exact size) is not important, although the size of the fields need to
* be png_byte or png_uint_16 (as defined below).
*/
typedef struct png_color_struct
{
png_byte red;
png_byte green;
png_byte blue;
} png_color;
typedef png_color * png_colorp;
typedef const png_color * png_const_colorp;
typedef png_color * * png_colorpp;
typedef struct png_color_16_struct
{
png_byte index; /* used for palette files */
png_uint_16 red; /* for use in red green blue files */
png_uint_16 green;
png_uint_16 blue;
png_uint_16 gray; /* for use in grayscale files */
} png_color_16;
typedef png_color_16 * png_color_16p;
typedef const png_color_16 * png_const_color_16p;
typedef png_color_16 * * png_color_16pp;
typedef struct png_color_8_struct
{
png_byte red; /* for use in red green blue files */
png_byte green;
png_byte blue;
png_byte gray; /* for use in grayscale files */
png_byte alpha; /* for alpha channel files */
} png_color_8;
typedef png_color_8 * png_color_8p;
typedef const png_color_8 * png_const_color_8p;
typedef png_color_8 * * png_color_8pp;
/*
* The following two structures are used for the in-core representation
* of sPLT chunks.
*/
typedef struct png_sPLT_entry_struct
{
png_uint_16 red;
png_uint_16 green;
png_uint_16 blue;
png_uint_16 alpha;
png_uint_16 frequency;
} png_sPLT_entry;
typedef png_sPLT_entry * png_sPLT_entryp;
typedef const png_sPLT_entry * png_const_sPLT_entryp;
typedef png_sPLT_entry * * png_sPLT_entrypp;
/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
* occupy the LSB of their respective members, and the MSB of each member
* is zero-filled. The frequency member always occupies the full 16 bits.
*/
typedef struct png_sPLT_struct
{
png_charp name; /* palette name */
png_byte depth; /* depth of palette samples */
png_sPLT_entryp entries; /* palette entries */
png_int_32 nentries; /* number of palette entries */
} png_sPLT_t;
typedef png_sPLT_t * png_sPLT_tp;
typedef const png_sPLT_t * png_const_sPLT_tp;
typedef png_sPLT_t * * png_sPLT_tpp;
#ifdef PNG_TEXT_SUPPORTED
/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
* and whether that contents is compressed or not. The "key" field
* points to a regular zero-terminated C string. The "text" fields can be a
* regular C string, an empty string, or a NULL pointer.
* However, the structure returned by png_get_text() will always contain
* the "text" field as a regular zero-terminated C string (possibly
* empty), never a NULL pointer, so it can be safely used in printf() and
* other string-handling functions. Note that the "itxt_length", "lang", and
* "lang_key" members of the structure only exist when the library is built
* with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
* default without iTXt support. Also note that when iTXt *is* supported,
* the "lang" and "lang_key" fields contain NULL pointers when the
* "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
* PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
* same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
* which is always 0 or 1, or its "compression method" which is always 0.
*/
typedef struct png_text_struct
{
int compression; /* compression value:
-1: tEXt, none
0: zTXt, deflate
1: iTXt, none
2: iTXt, deflate */
png_charp key; /* keyword, 1-79 character description of "text" */
png_charp text; /* comment, may be an empty string (ie "")
or a NULL pointer */
size_t text_length; /* length of the text string */
size_t itxt_length; /* length of the itxt string */
png_charp lang; /* language code, 0-79 characters
or a NULL pointer */
png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
chars or a NULL pointer */
} png_text;
typedef png_text * png_textp;
typedef const png_text * png_const_textp;
typedef png_text * * png_textpp;
#endif
/* Supported compression types for text in PNG files (tEXt, and zTXt).
* The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
#define PNG_TEXT_COMPRESSION_NONE_WR -3
#define PNG_TEXT_COMPRESSION_zTXt_WR -2
#define PNG_TEXT_COMPRESSION_NONE -1
#define PNG_TEXT_COMPRESSION_zTXt 0
#define PNG_ITXT_COMPRESSION_NONE 1
#define PNG_ITXT_COMPRESSION_zTXt 2
#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
/* png_time is a way to hold the time in an machine independent way.
* Two conversions are provided, both from time_t and struct tm. There
* is no portable way to convert to either of these structures, as far
* as I know. If you know of a portable way, send it to me. As a side
* note - PNG has always been Year 2000 compliant!
*/
typedef struct png_time_struct
{
png_uint_16 year; /* full year, as in, 1995 */
png_byte month; /* month of year, 1 - 12 */
png_byte day; /* day of month, 1 - 31 */
png_byte hour; /* hour of day, 0 - 23 */
png_byte minute; /* minute of hour, 0 - 59 */
png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
} png_time;
typedef png_time * png_timep;
typedef const png_time * png_const_timep;
typedef png_time * * png_timepp;
#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
defined(PNG_USER_CHUNKS_SUPPORTED)
/* png_unknown_chunk is a structure to hold queued chunks for which there is
* no specific support. The idea is that we can use this to queue
* up private chunks for output even though the library doesn't actually
* know about their semantics.
*
* The data in the structure is set by libpng on read and used on write.
*/
typedef struct png_unknown_chunk_t
{
png_byte name[5]; /* Textual chunk name with '\0' terminator */
png_byte *data; /* Data, should not be modified on read! */
size_t size;
/* On write 'location' must be set using the flag values listed below.
* Notice that on read it is set by libpng however the values stored have
* more bits set than are listed below. Always treat the value as a
* bitmask. On write set only one bit - setting multiple bits may cause the
* chunk to be written in multiple places.
*/
png_byte location; /* mode of operation at read time */
}
png_unknown_chunk;
typedef png_unknown_chunk * png_unknown_chunkp;
typedef const png_unknown_chunk * png_const_unknown_chunkp;
typedef png_unknown_chunk * * png_unknown_chunkpp;
#endif
/* Flag values for the unknown chunk location byte. */
#define PNG_HAVE_IHDR 0x01
#define PNG_HAVE_PLTE 0x02
#define PNG_AFTER_IDAT 0x08
/* Maximum positive integer used in PNG is (2^31)-1 */
#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
#define PNG_UINT_32_MAX ((png_uint_32)(-1))
#define PNG_SIZE_MAX ((size_t)(-1))
/* These are constants for fixed point values encoded in the
* PNG specification manner (x100000)
*/
#define PNG_FP_1 100000
#define PNG_FP_HALF 50000
#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
#define PNG_FP_MIN (-PNG_FP_MAX)
/* These describe the color_type field in png_info. */
/* color type masks */
#define PNG_COLOR_MASK_PALETTE 1
#define PNG_COLOR_MASK_COLOR 2
#define PNG_COLOR_MASK_ALPHA 4
/* color types. Note that not all combinations are legal */
#define PNG_COLOR_TYPE_GRAY 0
#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
/* aliases */
#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
/* This is for compression type. PNG 1.0-1.2 only define the single type. */
#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
/* This is for filter type. PNG 1.0-1.2 only define the single type. */
#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
/* These are for the interlacing type. These values should NOT be changed. */
#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
#define PNG_INTERLACE_LAST 2 /* Not a valid value */
/* These are for the oFFs chunk. These values should NOT be changed. */
#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
#define PNG_OFFSET_LAST 2 /* Not a valid value */
/* These are for the pCAL chunk. These values should NOT be changed. */
#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
#define PNG_EQUATION_LAST 4 /* Not a valid value */
/* These are for the sCAL chunk. These values should NOT be changed. */
#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
#define PNG_SCALE_METER 1 /* meters per pixel */
#define PNG_SCALE_RADIAN 2 /* radians per pixel */
#define PNG_SCALE_LAST 3 /* Not a valid value */
/* These are for the pHYs chunk. These values should NOT be changed. */
#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
#define PNG_RESOLUTION_METER 1 /* pixels/meter */
#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
/* These are for the sRGB chunk. These values should NOT be changed. */
#define PNG_sRGB_INTENT_PERCEPTUAL 0
#define PNG_sRGB_INTENT_RELATIVE 1
#define PNG_sRGB_INTENT_SATURATION 2
#define PNG_sRGB_INTENT_ABSOLUTE 3
#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
/* This is for text chunks */
#define PNG_KEYWORD_MAX_LENGTH 79
/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
#define PNG_MAX_PALETTE_LENGTH 256
/* These determine if an ancillary chunk's data has been successfully read
* from the PNG header, or if the application has filled in the corresponding
* data in the info_struct to be written into the output file. The values
* of the PNG_INFO_<chunk> defines should NOT be changed.
*/
#define PNG_INFO_gAMA 0x0001U
#define PNG_INFO_sBIT 0x0002U
#define PNG_INFO_cHRM 0x0004U
#define PNG_INFO_PLTE 0x0008U
#define PNG_INFO_tRNS 0x0010U
#define PNG_INFO_bKGD 0x0020U
#define PNG_INFO_hIST 0x0040U
#define PNG_INFO_pHYs 0x0080U
#define PNG_INFO_oFFs 0x0100U
#define PNG_INFO_tIME 0x0200U
#define PNG_INFO_pCAL 0x0400U
#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
#define PNG_INFO_cICP 0x20000U /* PNGv3: 1.6.45 */
#define PNG_INFO_cLLI 0x40000U /* PNGv3: 1.6.45 */
#define PNG_INFO_mDCV 0x80000U /* PNGv3: 1.6.45 */
/* APNG: these chunks are stored as unknown, these flags are never set
* however they are provided as a convenience for implementors of APNG and
* avoids any merge conflicts.
*
* Private chunks: these chunk names violate the chunk name recommendations
* because the chunk definitions have no signature and because the private
* chunks with these names have been reserved. Private definitions should
* avoid them.
*/
#define PNG_INFO_acTL 0x100000U /* PNGv3: 1.6.45: unknown */
#define PNG_INFO_fcTL 0x200000U /* PNGv3: 1.6.45: unknown */
#define PNG_INFO_fdAT 0x400000U /* PNGv3: 1.6.45: unknown */
/* This is used for the transformation routines, as some of them
* change these values for the row. It also should enable using
* the routines for other purposes.
*/
typedef struct png_row_info_struct
{
png_uint_32 width; /* width of row */
size_t rowbytes; /* number of bytes in row */
png_byte color_type; /* color type of row */
png_byte bit_depth; /* bit depth of row */
png_byte channels; /* number of channels (1, 2, 3, or 4) */
png_byte pixel_depth; /* bits per pixel (depth * channels) */
} png_row_info;
typedef png_row_info * png_row_infop;
typedef png_row_info * * png_row_infopp;
/* These are the function types for the I/O functions and for the functions
* that allow the user to override the default I/O functions with his or her
* own. The png_error_ptr type should match that of user-supplied warning
* and error functions, while the png_rw_ptr type should match that of the
* user read/write data functions. Note that the 'write' function must not
* modify the buffer it is passed. The 'read' function, on the other hand, is
* expected to return the read data in the buffer.
*/
typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
int));
typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
int));
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
/* The following callback receives png_uint_32 row_number, int pass for the
* png_bytep data of the row. When transforming an interlaced image the
* row number is the row number within the sub-image of the interlace pass, so
* the value will increase to the height of the sub-image (not the full image)
* then reset to 0 for the next pass.
*
* Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
* find the output pixel (x,y) given an interlaced sub-image pixel
* (row,col,pass). (See below for these macros.)
*/
typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
png_uint_32, int));
#endif
#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
png_bytep));
#endif
#ifdef PNG_USER_CHUNKS_SUPPORTED
typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
png_unknown_chunkp));
#endif
#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
/* not used anywhere */
/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
#endif
#ifdef PNG_SETJMP_SUPPORTED
/* This must match the function definition in <setjmp.h>, and the application
* must include this before png.h to obtain the definition of jmp_buf. The
* function is required to be PNG_NORETURN, but this is not checked. If the
* function does return the application will crash via an abort() or similar
* system level call.
*
* If you get a warning here while building the library you may need to make
* changes to ensure that pnglibconf.h records the calling convention used by
* your compiler. This may be very difficult - try using a different compiler
* to build the library!
*/
PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), (jmp_buf, int), typedef);
#endif
/* Transform masks for the high-level interface */
#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
/* Added to libpng-1.2.34 */
#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
/* Added to libpng-1.4.0 */
#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
/* Added to libpng-1.5.4 */
#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
#if ~0U > 0xffffU /* or else this might break on a 16-bit machine */
#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
#endif
/* Flags for MNG supported features */
#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
#define PNG_FLAG_MNG_FILTER_64 0x04
#define PNG_ALL_MNG_FEATURES 0x05
/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
* this allowed the zlib default functions to be used on Windows
* platforms. In 1.5 the zlib default malloc (which just calls malloc and
* ignores the first argument) should be completely compatible with the
* following.
*/
typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
png_alloc_size_t));
typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
/* Section 4: exported functions
* Here are the function definitions most commonly used. This is not
* the place to find out how to use libpng. See libpng-manual.txt for the
* full explanation, see example.c for the summary. This just provides
* a simple one line description of the use of each function.
*
* The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
* pngconf.h and in the *.dfn files in the scripts directory.
*
* PNG_EXPORT(ordinal, type, name, (args));
*
* ordinal: ordinal that is used while building
* *.def files. The ordinal value is only
* relevant when preprocessing png.h with
* the *.dfn files for building symbol table
* entries, and are removed by pngconf.h.
* type: return type of the function
* name: function name
* args: function arguments, with types
*
* When we wish to append attributes to a function prototype we use
* the PNG_EXPORTA() macro instead.
*
* PNG_EXPORTA(ordinal, type, name, (args), attributes);
*
* ordinal, type, name, and args: same as in PNG_EXPORT().
* attributes: function attributes
*/
/* Returns the version number of the library */
PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
/* Tell lib we have already handled the first <num_bytes> magic bytes.
* Handling more than 8 bytes from the beginning of the file is an error.
*/
PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
* PNG file. Returns zero if the supplied bytes match the 8-byte PNG
* signature, and non-zero otherwise. Having num_to_check == 0 or
* start > 7 will always fail (i.e. return non-zero).
*/
PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
size_t num_to_check));
/* Simple signature checking function. This is the same as calling
* png_check_sig(sig, n) := (png_sig_cmp(sig, 0, n) == 0).
*/
#define png_check_sig(sig, n) (png_sig_cmp((sig), 0, (n)) == 0) /* DEPRECATED */
/* Allocate and initialize png_ptr struct for reading, and any other memory. */
PNG_EXPORTA(4, png_structp, png_create_read_struct,
(png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn),
PNG_ALLOCATED);
/* Allocate and initialize png_ptr struct for writing, and any other memory */
PNG_EXPORTA(5, png_structp, png_create_write_struct,
(png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
png_error_ptr warn_fn),
PNG_ALLOCATED);
PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
(png_const_structrp png_ptr));
PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
size_t size));
/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
* match up.
*/
#ifdef PNG_SETJMP_SUPPORTED
/* This function returns the jmp_buf built in to *png_ptr. It must be
* supplied with an appropriate 'longjmp' function to use on that jmp_buf
* unless the default error function is overridden in which case NULL is
* acceptable. The size of the jmp_buf is checked against the actual size
* allocated by the library - the call will return NULL on a mismatch
* indicating an ABI mismatch.
*/
PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
# define png_jmpbuf(png_ptr) \
(*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
#else
# define png_jmpbuf(png_ptr) \
(LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
#endif
/* This function should be used by libpng applications in place of
* longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
* will use it; otherwise it will call PNG_ABORT(). This function was
* added in libpng-1.5.0.
*/
PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
PNG_NORETURN);
#ifdef PNG_READ_SUPPORTED
/* Reset the compression stream */
PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
#endif
/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
#ifdef PNG_USER_MEM_SUPPORTED
PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
(png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
png_error_ptr warn_fn,
png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
PNG_ALLOCATED);
PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
(png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
png_error_ptr warn_fn,
png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
PNG_ALLOCATED);
#endif