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/* png.h - header file for PNG reference library * * libpng version 1.6.37 - April 14, 2019 * * Copyright (c) 2018-2019 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 1.6.37, April 2019: * Cosmin Truta * See also "Contributing Authors", below. */ /* * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE * ========================================= * * PNG Reference Library License version 2 * --------------------------------------- * * * Copyright (c) 1995-2019 The PNG Reference Library Authors. * * Copyright (c) 2018-2019 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] * ... * 1.6.37 16 10637 16.so.16.37[.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. * * DLLNUM will change each time there are forward or backward changes * in binary compatibility (e.g., when a new feature is added). * * 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 /* 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 "1.6.37" #define PNG_HEADER_VERSION_STRING " libpng version 1.6.37 - April 14, 2019\n" #define PNG_LIBPNG_VER_SONUM 16 #define PNG_LIBPNG_VER_DLLNUM 16 /* 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 37 /* This should be zero for a public release, or non-zero for a * development version. [Deprecated] */ #define PNG_LIBPNG_VER_BUILD 0 /* 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_STABLE /* 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 10637 /* 1.6.37 */ /* 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_37; /* 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 */ /* 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), PNGARG((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 INT_MAX >= 0x8000 /* else this might break */ #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 (ie 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). */ #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n)) /* 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 /* Write the PNG file signature. */ PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr)); /* Write a PNG chunk - size, type, (optional) data, CRC. */ PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep chunk_name, png_const_bytep data, size_t length)); /* Write the start of a PNG chunk - length and chunk name. */ PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr, png_const_bytep chunk_name, png_uint_32 length)); /* Write the data of a PNG chunk started with png_write_chunk_start(). */ PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr, png_const_bytep data, size_t length)); /* Finish a chunk started with png_write_chunk_start() (includes CRC). */ PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr)); /* Allocate and initialize the info structure */ PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr), PNG_ALLOCATED); /* DEPRECATED: this function allowed init structures to be created using the * default allocation method (typically malloc). Use is deprecated in 1.6.0 and * the API will be removed in the future. */ PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr, size_t png_info_struct_size), PNG_DEPRECATED); /* Writes all the PNG information before the image. */ PNG_EXPORT(20, void, png_write_info_before_PLTE, (png_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(21, void, png_write_info, (png_structrp png_ptr, png_const_inforp info_ptr)); #ifdef PNG_SEQUENTIAL_READ_SUPPORTED /* Read the information before the actual image data. */ PNG_EXPORT(22, void, png_read_info, (png_structrp png_ptr, png_inforp info_ptr)); #endif #ifdef PNG_TIME_RFC1123_SUPPORTED /* Convert to a US string format: there is no localization support in this * routine. The original implementation used a 29 character buffer in * png_struct, this will be removed in future versions. */ #if PNG_LIBPNG_VER < 10700 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */ PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr, png_const_timep ptime),PNG_DEPRECATED); #endif PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29], png_const_timep ptime)); #endif #ifdef PNG_CONVERT_tIME_SUPPORTED /* Convert from a struct tm to png_time */ PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime, const struct tm * ttime)); /* Convert from time_t to png_time. Uses gmtime() */ PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime)); #endif /* CONVERT_tIME */ #ifdef PNG_READ_EXPAND_SUPPORTED /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */ PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr)); PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr)); PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr)); PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr)); #endif #ifdef PNG_READ_EXPAND_16_SUPPORTED /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion * of a tRNS chunk if present. */ PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr)); #endif #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) /* Use blue, green, red order for pixels. */ PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr)); #endif #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED /* Expand the grayscale to 24-bit RGB if necessary. */ PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr)); #endif #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED /* Reduce RGB to grayscale. */ #define PNG_ERROR_ACTION_NONE 1 #define PNG_ERROR_ACTION_WARN 2 #define PNG_ERROR_ACTION_ERROR 3 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/ PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr, int error_action, double red, double green)) PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr, int error_action, png_fixed_point red, png_fixed_point green)) PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp png_ptr)); #endif #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth, png_colorp palette)); #endif #ifdef PNG_READ_ALPHA_MODE_SUPPORTED /* How the alpha channel is interpreted - this affects how the color channels * of a PNG file are returned to the calling application when an alpha channel, * or a tRNS chunk in a palette file, is present. * * This has no effect on the way pixels are written into a PNG output * datastream. The color samples in a PNG datastream are never premultiplied * with the alpha samples. * * The default is to return data according to the PNG specification: the alpha * channel is a linear measure of the contribution of the pixel to the * corresponding composited pixel, and the color channels are unassociated * (not premultiplied). The gamma encoded color channels must be scaled * according to the contribution and to do this it is necessary to undo * the encoding, scale the color values, perform the composition and re-encode * the values. This is the 'PNG' mode. * * The alternative is to 'associate' the alpha with the color information by * storing color channel values that have been scaled by the alpha. * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes * (the latter being the two common names for associated alpha color channels). * * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha * value is equal to the maximum value. * * The final choice is to gamma encode the alpha channel as well. This is * broken because, in practice, no implementation that uses this choice * correctly undoes the encoding before handling alpha composition. Use this * choice only if other serious errors in the software or hardware you use * mandate it; the typical serious error is for dark halos to appear around * opaque areas of the composited PNG image because of arithmetic overflow. * * The API function png_set_alpha_mode specifies which of these choices to use * with an enumerated 'mode' value and the gamma of the required output: */ #define PNG_ALPHA_PNG 0 /* according to the PNG standard */ #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */ #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */ #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */ #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */ #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */ PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode, double output_gamma)) PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr, int mode, png_fixed_point output_gamma)) #endif #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED) /* The output_gamma value is a screen gamma in libpng terminology: it expresses * how to decode the output values, not how they are encoded. */ #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */ #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */ #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */ #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */ #endif /* The following are examples of calls to png_set_alpha_mode to achieve the * required overall gamma correction and, where necessary, alpha * premultiplication. * * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); * This is the default libpng handling of the alpha channel - it is not * pre-multiplied into the color components. In addition the call states * that the output is for a sRGB system and causes all PNG files without gAMA * chunks to be assumed to be encoded using sRGB. * * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); * In this case the output is assumed to be something like an sRGB conformant * display preceded by a power-law lookup table of power 1.45. This is how * early Mac systems behaved. * * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR); * This is the classic Jim Blinn approach and will work in academic * environments where everything is done by the book. It has the shortcoming * of assuming that input PNG data with no gamma information is linear - this * is unlikely to be correct unless the PNG files where generated locally. * Most of the time the output precision will be so low as to show * significant banding in dark areas of the image. * * png_set_expand_16(pp); * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB); * This is a somewhat more realistic Jim Blinn inspired approach. PNG files * are assumed to have the sRGB encoding if not marked with a gamma value and * the output is always 16 bits per component. This permits accurate scaling * and processing of the data. If you know that your input PNG files were * generated locally you might need to replace PNG_DEFAULT_sRGB with the * correct value for your system. * * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB); * If you just need to composite the PNG image onto an existing background * and if you control the code that does this you can use the optimization * setting. In this case you just copy completely opaque pixels to the * output. For pixels that are not completely transparent (you just skip * those) you do the composition math using png_composite or png_composite_16 * below then encode the resultant 8-bit or 16-bit values to match the output * encoding. * * Other cases * If neither the PNG nor the standard linear encoding work for you because * of the software or hardware you use then you have a big problem. The PNG * case will probably result in halos around the image. The linear encoding * will probably result in a washed out, too bright, image (it's actually too * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably * substantially reduce the halos. Alternatively try: * * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB); * This option will also reduce the halos, but there will be slight dark * halos round the opaque parts of the image where the background is light. * In the OPTIMIZED mode the halos will be light halos where the background * is dark. Take your pick - the halos are unavoidable unless you can get * your hardware/software fixed! (The OPTIMIZED approach is slightly * faster.) * * When the default gamma of PNG files doesn't match the output gamma. * If you have PNG files with no gamma information png_set_alpha_mode allows * you to provide a default gamma, but it also sets the output gamma to the * matching value. If you know your PNG files have a gamma that doesn't * match the output you can take advantage of the fact that * png_set_alpha_mode always sets the output gamma but only sets the PNG * default if it is not already set: * * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); * The first call sets both the default and the output gamma values, the * second call overrides the output gamma without changing the default. This * is easier than achieving the same effect with png_set_gamma. You must use * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will * fire if more than one call to png_set_alpha_mode and png_set_background is * made in the same read operation, however multiple calls with PNG_ALPHA_PNG * are ignored. */ #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr)); #endif #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr)); #endif #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr)); #endif #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) /* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */ PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler, int flags)); /* The values of the PNG_FILLER_ defines should NOT be changed */ # define PNG_FILLER_BEFORE 0 # define PNG_FILLER_AFTER 1 /* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */ PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr, png_uint_32 filler, int flags)); #endif /* READ_FILLER || WRITE_FILLER */ #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) /* Swap bytes in 16-bit depth files. */ PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr)); #endif #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */ PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr)); #endif #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \ defined(PNG_WRITE_PACKSWAP_SUPPORTED) /* Swap packing order of pixels in bytes. */ PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr)); #endif #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) /* Converts files to legal bit depths. */ PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p true_bits)); #endif #if defined(PNG_READ_INTERLACING_SUPPORTED) || \ defined(PNG_WRITE_INTERLACING_SUPPORTED) /* Have the code handle the interlacing. Returns the number of passes. * MUST be called before png_read_update_info or png_start_read_image, * otherwise it will not have the desired effect. Note that it is still * necessary to call png_read_row or png_read_rows png_get_image_height * times for each pass. */ PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr)); #endif #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) /* Invert monochrome files */ PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr)); #endif #ifdef PNG_READ_BACKGROUND_SUPPORTED /* Handle alpha and tRNS by replacing with a background color. Prior to * libpng-1.5.4 this API must not be called before the PNG file header has been * read. Doing so will result in unexpected behavior and possible warnings or * errors if the PNG file contains a bKGD chunk. */ PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr, png_const_color_16p background_color, int background_gamma_code, int need_expand, double background_gamma)) PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr, png_const_color_16p background_color, int background_gamma_code, int need_expand, png_fixed_point background_gamma)) #endif #ifdef PNG_READ_BACKGROUND_SUPPORTED # define PNG_BACKGROUND_GAMMA_UNKNOWN 0 # define PNG_BACKGROUND_GAMMA_SCREEN 1 # define PNG_BACKGROUND_GAMMA_FILE 2 # define PNG_BACKGROUND_GAMMA_UNIQUE 3 #endif #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* Scale a 16-bit depth file down to 8-bit, accurately. */ PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr)); #endif #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED #define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */ /* Strip the second byte of information from a 16-bit depth file. */ PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr)); #endif #ifdef PNG_READ_QUANTIZE_SUPPORTED /* Turn on quantizing, and reduce the palette to the number of colors * available. */ PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr, png_colorp palette, int num_palette, int maximum_colors, png_const_uint_16p histogram, int full_quantize)); #endif #ifdef PNG_READ_GAMMA_SUPPORTED /* The threshold on gamma processing is configurable but hard-wired into the * library. The following is the floating point variant. */ #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001) /* Handle gamma correction. Screen_gamma=(display_exponent). * NOTE: this API simply sets the screen and file gamma values. It will * therefore override the value for gamma in a PNG file if it is called after * the file header has been read - use with care - call before reading the PNG * file for best results! * * These routines accept the same gamma values as png_set_alpha_mode (described * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either * API (floating point or fixed.) Notice, however, that the 'file_gamma' value * is the inverse of a 'screen gamma' value. */ PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr, double screen_gamma, double override_file_gamma)) PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr, png_fixed_point screen_gamma, png_fixed_point override_file_gamma)) #endif #ifdef PNG_WRITE_FLUSH_SUPPORTED /* Set how many lines between output flushes - 0 for no flushing */ PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows)); /* Flush the current PNG output buffer */ PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr)); #endif /* Optional update palette with requested transformations */ PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr)); /* Optional call to update the users info structure */ PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr, png_inforp info_ptr)); #ifdef PNG_SEQUENTIAL_READ_SUPPORTED /* Read one or more rows of image data. */ PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row, png_bytepp display_row, png_uint_32 num_rows)); #endif #ifdef PNG_SEQUENTIAL_READ_SUPPORTED /* Read a row of data. */ PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row, png_bytep display_row)); #endif #ifdef PNG_SEQUENTIAL_READ_SUPPORTED /* Read the whole image into memory at once. */ PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image)); #endif /* Write a row of image data */ PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr, png_const_bytep row)); /* Write a few rows of image data: (*row) is not written; however, the type * is declared as writeable to maintain compatibility with previous versions * of libpng and to allow the 'display_row' array from read_rows to be passed * unchanged to write_rows. */ PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row, png_uint_32 num_rows)); /* Write the image data */ PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image)); /* Write the end of the PNG file. */ PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr, png_inforp info_ptr)); #ifdef PNG_SEQUENTIAL_READ_SUPPORTED /* Read the end of the PNG file. */ PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr)); #endif /* Free any memory associated with the png_info_struct */ PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr, png_infopp info_ptr_ptr)); /* Free any memory associated with the png_struct and the png_info_structs */ PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr)); /* Free any memory associated with the png_struct and the png_info_structs */ PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)); /* Set the libpng method of handling chunk CRC errors */ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action, int ancil_action)); /* Values for png_set_crc_action() say how to handle CRC errors in * ancillary and critical chunks, and whether to use the data contained * therein. Note that it is impossible to "discard" data in a critical * chunk. For versions prior to 0.90, the action was always error/quit, * whereas in version 0.90 and later, the action for CRC errors in ancillary * chunks is warn/discard. These values should NOT be changed. * * value action:critical action:ancillary */ #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */ #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */ #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */ #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */ #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */ #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */ #ifdef PNG_WRITE_SUPPORTED /* These functions give the user control over the scan-line filtering in * libpng and the compression methods used by zlib. These functions are * mainly useful for testing, as the defaults should work with most users. * Those users who are tight on memory or want faster performance at the * expense of compression can modify them. See the compression library * header file (zlib.h) for an explination of the compression functions. */ /* Set the filtering method(s) used by libpng. Currently, the only valid * value for "method" is 0. */ PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method, int filters)); #endif /* WRITE */ /* Flags for png_set_filter() to say which filters to use. The flags * are chosen so that they don't conflict with real filter types * below, in case they are supplied instead of the #defined constants. * These values should NOT be changed. */ #define PNG_NO_FILTERS 0x00 #define PNG_FILTER_NONE 0x08 #define PNG_FILTER_SUB 0x10 #define PNG_FILTER_UP 0x20 #define PNG_FILTER_AVG 0x40 #define PNG_FILTER_PAETH 0x80 #define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP) #define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH) /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now. * These defines should NOT be changed. */ #define PNG_FILTER_VALUE_NONE 0 #define PNG_FILTER_VALUE_SUB 1 #define PNG_FILTER_VALUE_UP 2 #define PNG_FILTER_VALUE_AVG 3 #define PNG_FILTER_VALUE_PAETH 4 #define PNG_FILTER_VALUE_LAST 5 #ifdef PNG_WRITE_SUPPORTED #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */ PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr, int heuristic_method, int num_weights, png_const_doublep filter_weights, png_const_doublep filter_costs)) PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed, (png_structrp png_ptr, int heuristic_method, int num_weights, png_const_fixed_point_p filter_weights, png_const_fixed_point_p filter_costs)) #endif /* WRITE_WEIGHTED_FILTER */ /* 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 */ #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */ /* Set the library compression level. Currently, valid values range from * 0 - 9, corresponding directly to the zlib compression levels 0 - 9 * (0 - no compression, 9 - "maximal" compression). Note that tests have * shown that zlib compression levels 3-6 usually perform as well as level 9 * for PNG images, and do considerably fewer caclulations. In the future, * these values may not correspond directly to the zlib compression levels. */ #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr, int level)); PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr, int mem_level)); PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr, int strategy)); /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a * smaller value of window_bits if it can do so safely. */ PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr, int window_bits)); PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr, int method)); #endif /* WRITE_CUSTOMIZE_COMPRESSION */ #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED /* Also set zlib parameters for compressing non-IDAT chunks */ PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr, int level)); PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr, int mem_level)); PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr, int strategy)); /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a * smaller value of window_bits if it can do so safely. */ PNG_EXPORT(225, void, png_set_text_compression_window_bits, (png_structrp png_ptr, int window_bits)); PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr, int method)); #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ #endif /* WRITE */ /* These next functions are called for input/output, memory, and error * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c, * and call standard C I/O routines such as fread(), fwrite(), and * fprintf(). These functions can be made to use other I/O routines * at run time for those applications that need to handle I/O in a * different manner by calling png_set_???_fn(). See libpng-manual.txt for * more information. */ #ifdef PNG_STDIO_SUPPORTED /* Initialize the input/output for the PNG file to the default functions. */ PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp)); #endif /* Replace the (error and abort), and warning functions with user * supplied functions. If no messages are to be printed you must still * write and use replacement functions. The replacement error_fn should * still do a longjmp to the last setjmp location if you are using this * method of error handling. If error_fn or warning_fn is NULL, the * default function will be used. */ PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr, png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn)); /* Return the user pointer associated with the error functions */ PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr)); /* Replace the default data output functions with a user supplied one(s). * If buffered output is not used, then output_flush_fn can be set to NULL. * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time * output_flush_fn will be ignored (and thus can be NULL). * It is probably a mistake to use NULL for output_flush_fn if * write_data_fn is not also NULL unless you have built libpng with * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's * default flush function, which uses the standard *FILE structure, will * be used. */ PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)); /* Replace the default data input function with a user supplied one. */ PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr, png_rw_ptr read_data_fn)); /* Return the user pointer associated with the I/O functions */ PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr)); PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr, png_read_status_ptr read_row_fn)); PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr, png_write_status_ptr write_row_fn)); #ifdef PNG_USER_MEM_SUPPORTED /* Replace the default memory allocation functions with user supplied one(s). */ PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn)); /* Return the user pointer associated with the memory functions */ PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr)); #endif #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr, png_user_transform_ptr read_user_transform_fn)); #endif #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr, png_user_transform_ptr write_user_transform_fn)); #endif #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr, png_voidp user_transform_ptr, int user_transform_depth, int user_transform_channels)); /* Return the user pointer associated with the user transform functions */ PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr, (png_const_structrp png_ptr)); #endif #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED /* Return information about the row currently being processed. Note that these * APIs do not fail but will return unexpected results if called outside a user * transform callback. Also note that 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.) */ PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp)); PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp)); #endif #ifdef PNG_READ_USER_CHUNKS_SUPPORTED /* This callback is called only for *unknown* chunks. If * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known * chunks to be treated as unknown, however in this case the callback must do * any processing required by the chunk (e.g. by calling the appropriate * png_set_ APIs.) * * There is no write support - on write, by default, all the chunks in the * 'unknown' list are written in the specified position. * * The integer return from the callback function is interpreted thus: * * negative: An error occurred; png_chunk_error will be called. * zero: The chunk was not handled, the chunk will be saved. A critical * chunk will cause an error at this point unless it is to be saved. * positive: The chunk was handled, libpng will ignore/discard it. * * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about * how this behavior will change in libpng 1.7 */ PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr, png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn)); #endif #ifdef PNG_USER_CHUNKS_SUPPORTED PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr)); #endif #ifdef PNG_PROGRESSIVE_READ_SUPPORTED /* Sets the function callbacks for the push reader, and a pointer to a * user-defined structure available to the callback functions. */ PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr, png_voidp progressive_ptr, png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn)); /* Returns the user pointer associated with the push read functions */ PNG_EXPORT(91, png_voidp, png_get_progressive_ptr, (png_const_structrp png_ptr)); /* Function to be called when data becomes available */ PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr, png_inforp info_ptr, png_bytep buffer, size_t buffer_size)); /* A function which may be called *only* within png_process_data to stop the * processing of any more data. The function returns the number of bytes * remaining, excluding any that libpng has cached internally. A subsequent * call to png_process_data must supply these bytes again. If the argument * 'save' is set to true the routine will first save all the pending data and * will always return 0. */ PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save)); /* A function which may be called *only* outside (after) a call to * png_process_data. It returns the number of bytes of data to skip in the * input. Normally it will return 0, but if it returns a non-zero value the * application must skip than number of bytes of input data and pass the * following data to the next call to png_process_data. */ PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp)); /* Function that combines rows. 'new_row' is a flag that should come from * the callback and be non-NULL if anything needs to be done; the library * stores its own version of the new data internally and ignores the passed * in value. */ PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr, png_bytep old_row, png_const_bytep new_row)); #endif /* PROGRESSIVE_READ */ PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr, png_alloc_size_t size), PNG_ALLOCATED); /* Added at libpng version 1.4.0 */ PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr, png_alloc_size_t size), PNG_ALLOCATED); /* Added at libpng version 1.2.4 */ PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr, png_alloc_size_t size), PNG_ALLOCATED); /* Frees a pointer allocated by png_malloc() */ PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr)); /* Free data that was allocated internally */ PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 free_me, int num)); /* Reassign responsibility for freeing existing data, whether allocated * by libpng or by the application; this works on the png_info structure passed * in, it does not change the state for other png_info structures. * * It is unlikely that this function works correctly as of 1.6.0 and using it * may result either in memory leaks or double free of allocated data. */ PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr, png_inforp info_ptr, int freer, png_uint_32 mask)); /* Assignments for png_data_freer */ #define PNG_DESTROY_WILL_FREE_DATA 1 #define PNG_SET_WILL_FREE_DATA 1 #define PNG_USER_WILL_FREE_DATA 2 /* Flags for png_ptr->free_me and info_ptr->free_me */ #define PNG_FREE_HIST 0x0008U #define PNG_FREE_ICCP 0x0010U #define PNG_FREE_SPLT 0x0020U #define PNG_FREE_ROWS 0x0040U #define PNG_FREE_PCAL 0x0080U #define PNG_FREE_SCAL 0x0100U #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED # define PNG_FREE_UNKN 0x0200U #endif /* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */ #define PNG_FREE_PLTE 0x1000U #define PNG_FREE_TRNS 0x2000U #define PNG_FREE_TEXT 0x4000U #define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */ #define PNG_FREE_ALL 0xffffU #define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */ #ifdef PNG_USER_MEM_SUPPORTED PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr, png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED); PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr, png_voidp ptr), PNG_DEPRECATED); #endif #ifdef PNG_ERROR_TEXT_SUPPORTED /* Fatal error in PNG image of libpng - can't continue */ PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr, png_const_charp error_message), PNG_NORETURN); /* The same, but the chunk name is prepended to the error string. */ PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr, png_const_charp error_message), PNG_NORETURN); #else /* Fatal error in PNG image of libpng - can't continue */ PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN); # define png_error(s1,s2) png_err(s1) # define png_chunk_error(s1,s2) png_err(s1) #endif #ifdef PNG_WARNINGS_SUPPORTED /* Non-fatal error in libpng. Can continue, but may have a problem. */ PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr, png_const_charp warning_message)); /* Non-fatal error in libpng, chunk name is prepended to message. */ PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr, png_const_charp warning_message)); #else # define png_warning(s1,s2) ((void)(s1)) # define png_chunk_warning(s1,s2) ((void)(s1)) #endif #ifdef PNG_BENIGN_ERRORS_SUPPORTED /* Benign error in libpng. Can continue, but may have a problem. * User can choose whether to handle as a fatal error or as a warning. */ PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr, png_const_charp warning_message)); #ifdef PNG_READ_SUPPORTED /* Same, chunk name is prepended to message (only during read) */ PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr, png_const_charp warning_message)); #endif PNG_EXPORT(109, void, png_set_benign_errors, (png_structrp png_ptr, int allowed)); #else # ifdef PNG_ALLOW_BENIGN_ERRORS # define png_benign_error png_warning # define png_chunk_benign_error png_chunk_warning # else # define png_benign_error png_error # define png_chunk_benign_error png_chunk_error # endif #endif /* The png_set_<chunk> functions are for storing values in the png_info_struct. * Similarly, the png_get_<chunk> calls are used to read values from the * png_info_struct, either storing the parameters in the passed variables, or * setting pointers into the png_info_struct where the data is stored. The * png_get_<chunk> functions return a non-zero value if the data was available * in info_ptr, or return zero and do not change any of the parameters if the * data was not available. * * These functions should be used instead of directly accessing png_info * to avoid problems with future changes in the size and internal layout of * png_info_struct. */ /* Returns "flag" if chunk data is valid in info_ptr. */ PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_uint_32 flag)); /* Returns number of bytes needed to hold a transformed row. */ PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr, png_const_inforp info_ptr)); #ifdef PNG_INFO_IMAGE_SUPPORTED /* Returns row_pointers, which is an array of pointers to scanlines that was * returned from png_read_png(). */ PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Set row_pointers, which is an array of pointers to scanlines for use * by png_write_png(). */ PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr, png_inforp info_ptr, png_bytepp row_pointers)); #endif /* Returns number of color channels in image. */ PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr, png_const_inforp info_ptr)); #ifdef PNG_EASY_ACCESS_SUPPORTED /* Returns image width in pixels. */ PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image height in pixels. */ PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image bit_depth. */ PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image color_type. */ PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image filter_type. */ PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image interlace_type. */ PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image compression_type. */ PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns image resolution in pixels per meter, from pHYs chunk data. */ PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter, (png_const_structrp png_ptr, png_const_inforp info_ptr)); /* Returns pixel aspect ratio, computed from pHYs chunk data. */ PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio, (png_const_structrp png_ptr, png_const_inforp info_ptr)) PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr)) /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */ PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(128, png_int_32, png_get_x_offset_microns, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(129, png_int_32, png_get_y_offset_microns, (png_const_structrp png_ptr, png_const_inforp info_ptr)); #endif /* EASY_ACCESS */ #ifdef PNG_READ_SUPPORTED /* Returns pointer to signature string read from PNG header */ PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr, png_const_inforp info_ptr)); #endif #ifdef PNG_bKGD_SUPPORTED PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr, png_inforp info_ptr, png_color_16p *background)); #endif #ifdef PNG_bKGD_SUPPORTED PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_color_16p background)); #endif #ifdef PNG_cHRM_SUPPORTED PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr, png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x, double *red_y, double *green_x, double *green_y, double *blue_x, double *blue_y)) PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr, png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z, double *green_X, double *green_Y, double *green_Z, double *blue_X, double *blue_Y, double *blue_Z)) PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_fixed_point *int_white_x, png_fixed_point *int_white_y, png_fixed_point *int_red_x, png_fixed_point *int_red_y, png_fixed_point *int_green_x, png_fixed_point *int_green_y, png_fixed_point *int_blue_x, png_fixed_point *int_blue_y)) PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_fixed_point *int_red_X, png_fixed_point *int_red_Y, png_fixed_point *int_red_Z, png_fixed_point *int_green_X, png_fixed_point *int_green_Y, png_fixed_point *int_green_Z, png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y, png_fixed_point *int_blue_Z)) #endif #ifdef PNG_cHRM_SUPPORTED PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr, png_inforp info_ptr, double white_x, double white_y, double red_x, double red_y, double green_x, double green_y, double blue_x, double blue_y)) PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr, png_inforp info_ptr, double red_X, double red_Y, double red_Z, double green_X, double green_Y, double green_Z, double blue_X, double blue_Y, double blue_Z)) PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr, png_inforp info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y, png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x, png_fixed_point int_blue_y)) PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr, png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y, png_fixed_point int_red_Z, png_fixed_point int_green_X, png_fixed_point int_green_Y, png_fixed_point int_green_Z, png_fixed_point int_blue_X, png_fixed_point int_blue_Y, png_fixed_point int_blue_Z)) #endif #ifdef PNG_eXIf_SUPPORTED PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr, png_inforp info_ptr, png_bytep *exif)); PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr, png_inforp info_ptr, png_bytep exif)); PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif)); PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif)); #endif #ifdef PNG_gAMA_SUPPORTED PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr, png_const_inforp info_ptr, double *file_gamma)) PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_fixed_point *int_file_gamma)) #endif #ifdef PNG_gAMA_SUPPORTED PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma)) PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr, png_inforp info_ptr, png_fixed_point int_file_gamma)) #endif #ifdef PNG_hIST_SUPPORTED PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr, png_inforp info_ptr, png_uint_16p *hist)); PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_uint_16p hist)); #endif PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height, int *bit_depth, int *color_type, int *interlace_method, int *compression_method, int *filter_method)); PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, int color_type, int interlace_method, int compression_method, int filter_method)); #ifdef PNG_oFFs_SUPPORTED PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)); #endif #ifdef PNG_oFFs_SUPPORTED PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr, png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y, int unit_type)); #endif #ifdef PNG_pCAL_SUPPORTED PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr, png_inforp info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams, png_charp *units, png_charpp *params)); #endif #ifdef PNG_pCAL_SUPPORTED PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams, png_const_charp units, png_charpp params)); #endif #ifdef PNG_pHYs_SUPPORTED PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)); #endif #ifdef PNG_pHYs_SUPPORTED PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type)); #endif PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr, png_inforp info_ptr, png_colorp *palette, int *num_palette)); PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr, png_inforp info_ptr, png_const_colorp palette, int num_palette)); #ifdef PNG_sBIT_SUPPORTED PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr, png_inforp info_ptr, png_color_8p *sig_bit)); #endif #ifdef PNG_sBIT_SUPPORTED PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_color_8p sig_bit)); #endif #ifdef PNG_sRGB_SUPPORTED PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr, png_const_inforp info_ptr, int *file_srgb_intent)); #endif #ifdef PNG_sRGB_SUPPORTED PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)); PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)); #endif #ifdef PNG_iCCP_SUPPORTED PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr, png_inforp info_ptr, png_charpp name, int *compression_type, png_bytepp profile, png_uint_32 *proflen)); #endif #ifdef PNG_iCCP_SUPPORTED PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_charp name, int compression_type, png_const_bytep profile, png_uint_32 proflen)); #endif #ifdef PNG_sPLT_SUPPORTED PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr, png_inforp info_ptr, png_sPLT_tpp entries)); #endif #ifdef PNG_sPLT_SUPPORTED PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)); #endif #ifdef PNG_TEXT_SUPPORTED /* png_get_text also returns the number of text chunks in *num_text */ PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr, png_inforp info_ptr, png_textp *text_ptr, int *num_text)); #endif /* Note while png_set_text() will accept a structure whose text, * language, and translated keywords are NULL pointers, the structure * returned by png_get_text will always contain regular * zero-terminated C strings. They might be empty strings but * they will never be NULL pointers. */ #ifdef PNG_TEXT_SUPPORTED PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_textp text_ptr, int num_text)); #endif #ifdef PNG_tIME_SUPPORTED PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr, png_inforp info_ptr, png_timep *mod_time)); #endif #ifdef PNG_tIME_SUPPORTED PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_timep mod_time)); #endif #ifdef PNG_tRNS_SUPPORTED PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr, png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)); #endif #ifdef PNG_tRNS_SUPPORTED PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr, png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)); #endif #ifdef PNG_sCAL_SUPPORTED PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, double *width, double *height)) #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \ defined(PNG_FLOATING_POINT_SUPPORTED) /* NOTE: this API is currently implemented using floating point arithmetic, * consequently it can only be used on systems with floating point support. * In any case the range of values supported by png_fixed_point is small and it * is highly recommended that png_get_sCAL_s be used instead. */ PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, png_fixed_point *width, png_fixed_point *height)) #endif PNG_EXPORT(169, png_uint_32, png_get_sCAL_s, (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, png_charpp swidth, png_charpp sheight)); PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr, png_inforp info_ptr, int unit, double width, double height)) PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr, png_inforp info_ptr, int unit, png_fixed_point width, png_fixed_point height)) PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr, png_inforp info_ptr, int unit, png_const_charp swidth, png_const_charp sheight)); #endif /* sCAL */ #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED /* Provide the default handling for all unknown chunks or, optionally, for * specific unknown chunks. * * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was * ignored and the default was used, the per-chunk setting only had an effect on * write. If you wish to have chunk-specific handling on read in code that must * work on earlier versions you must use a user chunk callback to specify the * desired handling (keep or discard.) * * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The * parameter is interpreted as follows: * * READ: * PNG_HANDLE_CHUNK_AS_DEFAULT: * Known chunks: do normal libpng processing, do not keep the chunk (but * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED) * Unknown chunks: for a specific chunk use the global default, when used * as the default discard the chunk data. * PNG_HANDLE_CHUNK_NEVER: * Discard the chunk data. * PNG_HANDLE_CHUNK_IF_SAFE: * Keep the chunk data if the chunk is not critical else raise a chunk * error. * PNG_HANDLE_CHUNK_ALWAYS: * Keep the chunk data. * * If the chunk data is saved it can be retrieved using png_get_unknown_chunks, * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks * it simply resets the behavior to the libpng default. * * INTERACTION WITH USER CHUNK CALLBACKS: * The per-chunk handling is always used when there is a png_user_chunk_ptr * callback and the callback returns 0; the chunk is then always stored *unless* * it is critical and the per-chunk setting is other than ALWAYS. Notice that * the global default is *not* used in this case. (In effect the per-chunk * value is incremented to at least IF_SAFE.) * * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and * per-chunk defaults will be honored. If you want to preserve the current * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE * as the default - if you don't do this libpng 1.6 will issue a warning. * * If you want unhandled unknown chunks to be discarded in libpng 1.6 and * earlier simply return '1' (handled). * * PNG_HANDLE_AS_UNKNOWN_SUPPORTED: * If this is *not* set known chunks will always be handled by libpng and * will never be stored in the unknown chunk list. Known chunks listed to * png_set_keep_unknown_chunks will have no effect. If it is set then known * chunks listed with a keep other than AS_DEFAULT will *never* be processed * by libpng, in addition critical chunks must either be processed by the * callback or saved. * * The IHDR and IEND chunks must not be listed. Because this turns off the * default handling for chunks that would otherwise be recognized the * behavior of libpng transformations may well become incorrect! * * WRITE: * When writing chunks the options only apply to the chunks specified by * png_set_unknown_chunks (below), libpng will *always* write known chunks * required by png_set_ calls and will always write the core critical chunks * (as required for PLTE). * * Each chunk in the png_set_unknown_chunks list is looked up in the * png_set_keep_unknown_chunks list to find the keep setting, this is then * interpreted as follows: * * PNG_HANDLE_CHUNK_AS_DEFAULT: * Write safe-to-copy chunks and write other chunks if the global * default is set to _ALWAYS, otherwise don't write this chunk. * PNG_HANDLE_CHUNK_NEVER: * Do not write the chunk. * PNG_HANDLE_CHUNK_IF_SAFE: * Write the chunk if it is safe-to-copy, otherwise do not write it. * PNG_HANDLE_CHUNK_ALWAYS: * Write the chunk. * * Note that the default behavior is effectively the opposite of the read case - * in read unknown chunks are not stored by default, in write they are written * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different * - on write the safe-to-copy bit is checked, on read the critical bit is * checked and on read if the chunk is critical an error will be raised. * * num_chunks: * =========== * If num_chunks is positive, then the "keep" parameter specifies the manner * for handling only those chunks appearing in the chunk_list array, * otherwise the chunk list array is ignored. * * If num_chunks is 0 the "keep" parameter specifies the default behavior for * unknown chunks, as described above. * * If num_chunks is negative, then the "keep" parameter specifies the manner * for handling all unknown chunks plus all chunks recognized by libpng * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to * be processed by libpng. */ #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr, int keep, png_const_bytep chunk_list, int num_chunks)); #endif /* HANDLE_AS_UNKNOWN */ /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned; * the result is therefore true (non-zero) if special handling is required, * false for the default handling. */ PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr, png_const_bytep chunk_name)); #endif /* SET_UNKNOWN_CHUNKS */ #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr, png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)); /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added * unknowns to the location currently stored in the png_struct. This is * invariably the wrong value on write. To fix this call the following API * for each chunk in the list with the correct location. If you know your * code won't be compiled on earlier versions you can rely on * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing * the correct thing. */ PNG_EXPORT(175, void, png_set_unknown_chunk_location, (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location)); PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr, png_inforp info_ptr, png_unknown_chunkpp entries)); #endif /* Png_free_data() will turn off the "valid" flag for anything it frees. * If you need to turn it off for a chunk that your application has freed, * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); */ PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr, png_inforp info_ptr, int mask)); #ifdef PNG_INFO_IMAGE_SUPPORTED /* The "params" pointer is currently not used and is for future expansion. */ #ifdef PNG_SEQUENTIAL_READ_SUPPORTED PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr, int transforms, png_voidp params)); #endif #ifdef PNG_WRITE_SUPPORTED PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr, int transforms, png_voidp params)); #endif #endif PNG_EXPORT(180, png_const_charp, png_get_copyright, (png_const_structrp png_ptr)); PNG_EXPORT(181, png_const_charp, png_get_header_ver, (png_const_structrp png_ptr)); PNG_EXPORT(182, png_const_charp, png_get_header_version, (png_const_structrp png_ptr)); PNG_EXPORT(183, png_const_charp, png_get_libpng_ver, (png_const_structrp png_ptr)); #ifdef PNG_MNG_FEATURES_SUPPORTED PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr, png_uint_32 mng_features_permitted)); #endif /* For use in png_set_keep_unknown, added to version 1.2.6 */ #define PNG_HANDLE_CHUNK_AS_DEFAULT 0 #define PNG_HANDLE_CHUNK_NEVER 1 #define PNG_HANDLE_CHUNK_IF_SAFE 2 #define PNG_HANDLE_CHUNK_ALWAYS 3 #define PNG_HANDLE_CHUNK_LAST 4 /* Strip the prepended error numbers ("#nnn ") from error and warning * messages before passing them to the error or warning handler. */ #ifdef PNG_ERROR_NUMBERS_SUPPORTED PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr, png_uint_32 strip_mode)); #endif /* Added in libpng-1.2.6 */ #ifdef PNG_SET_USER_LIMITS_SUPPORTED PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max)); PNG_EXPORT(187, png_uint_32, png_get_user_width_max, (png_const_structrp png_ptr)); PNG_EXPORT(188, png_uint_32, png_get_user_height_max, (png_const_structrp png_ptr)); /* Added in libpng-1.4.0 */ PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)); PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max, (png_const_structrp png_ptr)); /* Added in libpng-1.4.1 */ PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr, png_alloc_size_t user_chunk_cache_max)); PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max, (png_const_structrp png_ptr)); #endif #if defined(PNG_INCH_CONVERSIONS_SUPPORTED) PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch, (png_const_structrp png_ptr, png_const_inforp info_ptr)); PNG_FP_EXPORT(196, float, png_get_x_offset_inches, (png_const_structrp png_ptr, png_const_inforp info_ptr)) #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr)) #endif PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr, png_const_inforp info_ptr)) #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed, (png_const_structrp png_ptr, png_const_inforp info_ptr)) #endif # ifdef PNG_pHYs_SUPPORTED PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr, png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)); # endif /* pHYs */ #endif /* INCH_CONVERSIONS */ /* Added in libpng-1.4.0 */ #ifdef PNG_IO_STATE_SUPPORTED PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr)); /* Removed from libpng 1.6; use png_get_io_chunk_type. */ PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr), PNG_DEPRECATED) PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type, (png_const_structrp png_ptr)); /* The flags returned by png_get_io_state() are the following: */ # define PNG_IO_NONE 0x0000 /* no I/O at this moment */ # define PNG_IO_READING 0x0001 /* currently reading */ # define PNG_IO_WRITING 0x0002 /* currently writing */ # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */ # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */ # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */ # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */ # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */ # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */ #endif /* IO_STATE */ /* Interlace support. The following macros are always defined so that if * libpng interlace handling is turned off the macros may be used to handle * interlaced images within the application. */ #define PNG_INTERLACE_ADAM7_PASSES 7 /* Two macros to return the first row and first column of the original, * full, image which appears in a given pass. 'pass' is in the range 0 * to 6 and the result is in the range 0 to 7. */ #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7) #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7) /* A macro to return the offset between pixels in the output row for a pair of * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that * follows. Note that ROW_OFFSET is the offset from one row to the next whereas * COL_OFFSET is from one column to the next, within a row. */ #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8) #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1)) /* Two macros to help evaluate the number of rows or columns in each * pass. This is expressed as a shift - effectively log2 of the number or * rows or columns in each 8x8 tile of the original image. */ #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3) #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3) /* Hence two macros to determine the number of rows or columns in a given * pass of an image given its height or width. In fact these macros may * return non-zero even though the sub-image is empty, because the other * dimension may be empty for a small image. */ #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\ -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass)) #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\ -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass)) /* For the reader row callbacks (both progressive and sequential) it is * necessary to find the row in the output image given a row in an interlaced * image, so two more macros: */ #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \ (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass)) #define PNG_COL_FROM_PASS_COL(x_in, pass) \ (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass)) /* Two macros which return a boolean (0 or 1) saying whether the given row * or column is in a particular pass. These use a common utility macro that * returns a mask for a given pass - the offset 'off' selects the row or * column version. The mask has the appropriate bit set for each column in * the tile. */ #define PNG_PASS_MASK(pass,off) ( \ ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \ ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0)) #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \ ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1) #define PNG_COL_IN_INTERLACE_PASS(x, pass) \ ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1) #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED /* With these routines we avoid an integer divide, which will be slower on * most machines. However, it does take more operations than the corresponding * divide method, so it may be slower on a few RISC systems. There are two * shifts (by 8 or 16 bits) and an addition, versus a single integer divide. * * Note that the rounding factors are NOT supposed to be the same! 128 and * 32768 are correct for the NODIV code; 127 and 32767 are correct for the * standard method. * * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ] */ /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */ # define png_composite(composite, fg, alpha, bg) \ { \ png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \ * (png_uint_16)(alpha) \ + (png_uint_16)(bg)*(png_uint_16)(255 \ - (png_uint_16)(alpha)) + 128); \ (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \ } # define png_composite_16(composite, fg, alpha, bg) \ { \ png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \ * (png_uint_32)(alpha) \ + (png_uint_32)(bg)*(65535 \ - (png_uint_32)(alpha)) + 32768); \ (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \ } #else /* Standard method using integer division */ # define png_composite(composite, fg, alpha, bg) \ (composite) = \ (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \ (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \ 127) / 255)) # define png_composite_16(composite, fg, alpha, bg) \ (composite) = \ (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \ (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \ 32767) / 65535)) #endif /* READ_COMPOSITE_NODIV */ #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf)); PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf)); PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf)); #endif PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr, png_const_bytep buf)); /* No png_get_int_16 -- may be added if there's a real need for it. */ /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */ #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i)); #endif #ifdef PNG_SAVE_INT_32_SUPPORTED PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i)); #endif /* Place a 16-bit number into a buffer in PNG byte order. * The parameter is declared unsigned int, not png_uint_16, * just to avoid potential problems on pre-ANSI C compilers. */ #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i)); /* No png_save_int_16 -- may be added if there's a real need for it. */ #endif #ifdef PNG_USE_READ_MACROS /* Inline macros to do direct reads of bytes from the input buffer. * The png_get_int_32() routine assumes we are using two's complement * format for negative values, which is almost certainly true. */ # define PNG_get_uint_32(buf) \ (((png_uint_32)(*(buf)) << 24) + \ ((png_uint_32)(*((buf) + 1)) << 16) + \ ((png_uint_32)(*((buf) + 2)) << 8) + \ ((png_uint_32)(*((buf) + 3)))) /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the * function) incorrectly returned a value of type png_uint_32. */ # define PNG_get_uint_16(buf) \ ((png_uint_16) \ (((unsigned int)(*(buf)) << 8) + \ ((unsigned int)(*((buf) + 1))))) # define PNG_get_int_32(buf) \ ((png_int_32)((*(buf) & 0x80) \ ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \ : (png_int_32)png_get_uint_32(buf))) /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h, * but defining a macro name prefixed with PNG_PREFIX. */ # ifndef PNG_PREFIX # define png_get_uint_32(buf) PNG_get_uint_32(buf) # define png_get_uint_16(buf) PNG_get_uint_16(buf) # define png_get_int_32(buf) PNG_get_int_32(buf) # endif #else # ifdef PNG_PREFIX /* No macros; revert to the (redefined) function */ # define PNG_get_uint_32 (png_get_uint_32) # define PNG_get_uint_16 (png_get_uint_16) # define PNG_get_int_32 (png_get_int_32) # endif #endif #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED PNG_EXPORT(242, void, png_set_check_for_invalid_index, (png_structrp png_ptr, int allowed)); # ifdef PNG_GET_PALETTE_MAX_SUPPORTED PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr, png_const_infop info_ptr)); # endif #endif /* CHECK_FOR_INVALID_INDEX */ /******************************************************************************* * Section 5: SIMPLIFIED API ******************************************************************************* * * Please read the documentation in libpng-manual.txt (TODO: write said * documentation) if you don't understand what follows. * * The simplified API hides the details of both libpng and the PNG file format * itself. It allows PNG files to be read into a very limited number of * in-memory bitmap formats or to be written from the same formats. If these * formats do not accommodate your needs then you can, and should, use the more * sophisticated APIs above - these support a wide variety of in-memory formats * and a wide variety of sophisticated transformations to those formats as well * as a wide variety of APIs to manipulate ancillary information. * * To read a PNG file using the simplified API: * * 1) Declare a 'png_image' structure (see below) on the stack, set the * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL * (this is REQUIRED, your program may crash if you don't do it.) * 2) Call the appropriate png_image_begin_read... function. * 3) Set the png_image 'format' member to the required sample format. * 4) Allocate a buffer for the image and, if required, the color-map. * 5) Call png_image_finish_read to read the image and, if required, the * color-map into your buffers. * * There are no restrictions on the format of the PNG input itself; all valid * color types, bit depths, and interlace methods are acceptable, and the * input image is transformed as necessary to the requested in-memory format * during the png_image_finish_read() step. The only caveat is that if you * request a color-mapped image from a PNG that is full-color or makes * complex use of an alpha channel the transformation is extremely lossy and the * result may look terrible. * * To write a PNG file using the simplified API: * * 1) Declare a 'png_image' structure on the stack and memset() it to all zero. * 2) Initialize the members of the structure that describe the image, setting * the 'format' member to the format of the image samples. * 3) Call the appropriate png_image_write... function with a pointer to the * image and, if necessary, the color-map to write the PNG data. * * png_image is a structure that describes the in-memory format of an image * when it is being read or defines the in-memory format of an image that you * need to write: */ #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) #define PNG_IMAGE_VERSION 1 typedef struct png_control *png_controlp; typedef struct { png_controlp opaque; /* Initialize to NULL, free with png_image_free */ png_uint_32 version; /* Set to PNG_IMAGE_VERSION */ png_uint_32 width; /* Image width in pixels (columns) */ png_uint_32 height; /* Image height in pixels (rows) */ png_uint_32 format; /* Image format as defined below */ png_uint_32 flags; /* A bit mask containing informational flags */ png_uint_32 colormap_entries; /* Number of entries in the color-map */ /* In the event of an error or warning the following field will be set to a * non-zero value and the 'message' field will contain a '\0' terminated * string with the libpng error or warning message. If both warnings and * an error were encountered, only the error is recorded. If there * are multiple warnings, only the first one is recorded. * * The upper 30 bits of this value are reserved, the low two bits contain * a value as follows: */ # define PNG_IMAGE_WARNING 1 # define PNG_IMAGE_ERROR 2 /* * The result is a two-bit code such that a value more than 1 indicates * a failure in the API just called: * * 0 - no warning or error * 1 - warning * 2 - error * 3 - error preceded by warning */ # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1) png_uint_32 warning_or_error; char message[64]; } png_image, *png_imagep; /* The samples of the image have one to four channels whose components have * original values in the range 0 to 1.0: * * 1: A single gray or luminance channel (G). * 2: A gray/luminance channel and an alpha channel (GA). * 3: Three red, green, blue color channels (RGB). * 4: Three color channels and an alpha channel (RGBA). * * The components are encoded in one of two ways: * * a) As a small integer, value 0..255, contained in a single byte. For the * alpha channel the original value is simply value/255. For the color or * luminance channels the value is encoded according to the sRGB specification * and matches the 8-bit format expected by typical display devices. * * The color/gray channels are not scaled (pre-multiplied) by the alpha * channel and are suitable for passing to color management software. * * b) As a value in the range 0..65535, contained in a 2-byte integer. All * channels can be converted to the original value by dividing by 65535; all * channels are linear. Color channels use the RGB encoding (RGB end-points) of * the sRGB specification. This encoding is identified by the * PNG_FORMAT_FLAG_LINEAR flag below. * * When the simplified API needs to convert between sRGB and linear colorspaces, * the actual sRGB transfer curve defined in the sRGB specification (see the * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2 * approximation used elsewhere in libpng. * * When an alpha channel is present it is expected to denote pixel coverage * of the color or luminance channels and is returned as an associated alpha * channel: the color/gray channels are scaled (pre-multiplied) by the alpha * value. * * The samples are either contained directly in the image data, between 1 and 8 * bytes per pixel according to the encoding, or are held in a color-map indexed * by bytes in the image data. In the case of a color-map the color-map entries * are individual samples, encoded as above, and the image data has one byte per * pixel to select the relevant sample from the color-map. */ /* PNG_FORMAT_* * * #defines to be used in png_image::format. Each #define identifies a * particular layout of sample data and, if present, alpha values. There are * separate defines for each of the two component encodings. * * A format is built up using single bit flag values. All combinations are * valid. Formats can be built up from the flag values or you can use one of * the predefined values below. When testing formats always use the FORMAT_FLAG * macros to test for individual features - future versions of the library may * add new flags. * * When reading or writing color-mapped images the format should be set to the * format of the entries in the color-map then png_image_{read,write}_colormap * called to read or write the color-map and set the format correctly for the * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly! * * NOTE: libpng can be built with particular features disabled. If you see * compiler errors because the definition of one of the following flags has been * compiled out it is because libpng does not have the required support. It is * possible, however, for the libpng configuration to enable the format on just * read or just write; in that case you may see an error at run time. You can * guard against this by checking for the definition of the appropriate * "_SUPPORTED" macro, one of: * * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED */ #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */ #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */ #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */ #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */ #ifdef PNG_FORMAT_BGR_SUPPORTED # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */ #endif #ifdef PNG_FORMAT_AFIRST_SUPPORTED # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */ #endif #define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */ /* Commonly used formats have predefined macros. * * First the single byte (sRGB) formats: */ #define PNG_FORMAT_GRAY 0 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST) #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR) #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA) #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST) #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA) #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST) /* Then the linear 2-byte formats. When naming these "Y" is used to * indicate a luminance (gray) channel. */ #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA) #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR) #define PNG_FORMAT_LINEAR_RGB_ALPHA \ (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA) /* With color-mapped formats the image data is one byte for each pixel, the byte * is an index into the color-map which is formatted as above. To obtain a * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP * to one of the above definitions, or you can use one of the definitions below. */ #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP) #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP) #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP) #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP) #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP) #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP) /* PNG_IMAGE macros * * These are convenience macros to derive information from a png_image * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the * actual image sample values - either the entries in the color-map or the * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values * for the pixels and will always return 1 for color-mapped formats. The * remaining macros return information about the rows in the image and the * complete image. * * NOTE: All the macros that take a png_image::format parameter are compile time * constants if the format parameter is, itself, a constant. Therefore these * macros can be used in array declarations and case labels where required. * Similarly the macros are also pre-processor constants (sizeof is not used) so * they can be used in #if tests. * * First the information about the samples. */ #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\ (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1) /* Return the total number of channels in a given format: 1..4 */ #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\ ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1) /* Return the size in bytes of a single component of a pixel or color-map * entry (as appropriate) in the image: 1 or 2. */ #define PNG_IMAGE_SAMPLE_SIZE(fmt)\ (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)) /* This is the size of the sample data for one sample. If the image is * color-mapped it is the size of one color-map entry (and image pixels are * one byte in size), otherwise it is the size of one image pixel. */ #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\ (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256) /* The maximum size of the color-map required by the format expressed in a * count of components. This can be used to compile-time allocate a * color-map: * * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)]; * * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)]; * * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the * information from one of the png_image_begin_read_ APIs and dynamically * allocate the required memory. */ /* Corresponding information about the pixels */ #define PNG_IMAGE_PIXEL_(test,fmt)\ (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt)) #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\ PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt) /* The number of separate channels (components) in a pixel; 1 for a * color-mapped image. */ #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\ PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt) /* The size, in bytes, of each component in a pixel; 1 for a color-mapped * image. */ #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt) /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */ /* Information about the whole row, or whole image */ #define PNG_IMAGE_ROW_STRIDE(image)\ (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width) /* Return the total number of components in a single row of the image; this * is the minimum 'row stride', the minimum count of components between each * row. For a color-mapped image this is the minimum number of bytes in a * row. * * WARNING: this macro overflows for some images with more than one component * and very large image widths. libpng will refuse to process an image where * this macro would overflow. */ #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\ (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride)) /* Return the size, in bytes, of an image buffer given a png_image and a row * stride - the number of components to leave space for in each row. * * WARNING: this macro overflows a 32-bit integer for some large PNG images, * libpng will refuse to process an image where such an overflow would occur. */ #define PNG_IMAGE_SIZE(image)\ PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image)) /* Return the size, in bytes, of the image in memory given just a png_image; * the row stride is the minimum stride required for the image. */ #define PNG_IMAGE_COLORMAP_SIZE(image)\ (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries) /* Return the size, in bytes, of the color-map of this image. If the image * format is not a color-map format this will return a size sufficient for * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if * you don't want to allocate a color-map in this case. */ /* PNG_IMAGE_FLAG_* * * Flags containing additional information about the image are held in the * 'flags' field of png_image. */ #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01 /* This indicates that the RGB values of the in-memory bitmap do not * correspond to the red, green and blue end-points defined by sRGB. */ #define PNG_IMAGE_FLAG_FAST 0x02 /* On write emphasise speed over compression; the resultant PNG file will be * larger but will be produced significantly faster, particular for large * images. Do not use this option for images which will be distributed, only * used it when producing intermediate files that will be read back in * repeatedly. For a typical 24-bit image the option will double the read * speed at the cost of increasing the image size by 25%, however for many * more compressible images the PNG file can be 10 times larger with only a * slight speed gain. */ #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04 /* On read if the image is a 16-bit per component image and there is no gAMA * or sRGB chunk assume that the components are sRGB encoded. Notice that * images output by the simplified API always have gamma information; setting * this flag only affects the interpretation of 16-bit images from an * external source. It is recommended that the application expose this flag * to the user; the user can normally easily recognize the difference between * linear and sRGB encoding. This flag has no effect on write - the data * passed to the write APIs must have the correct encoding (as defined * above.) * * If the flag is not set (the default) input 16-bit per component data is * assumed to be linear. * * NOTE: the flag can only be set after the png_image_begin_read_ call, * because that call initializes the 'flags' field. */ #ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* READ APIs * --------- * * The png_image passed to the read APIs must have been initialized by setting * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.) */ #ifdef PNG_STDIO_SUPPORTED PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image, const char *file_name)); /* The named file is opened for read and the image header is filled in * from the PNG header in the file. */ PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image, FILE* file)); /* The PNG header is read from the stdio FILE object. */ #endif /* STDIO */ PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image, png_const_voidp memory, size_t size)); /* The PNG header is read from the given memory buffer. */ PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image, png_const_colorp background, void *buffer, png_int_32 row_stride, void *colormap)); /* Finish reading the image into the supplied buffer and clean up the * png_image structure. * * row_stride is the step, in byte or 2-byte units as appropriate, * between adjacent rows. A positive stride indicates that the top-most row * is first in the buffer - the normal top-down arrangement. A negative * stride indicates that the bottom-most row is first in the buffer. * * background need only be supplied if an alpha channel must be removed from * a png_byte format and the removal is to be done by compositing on a solid * color; otherwise it may be NULL and any composition will be done directly * onto the buffer. The value is an sRGB color to use for the background, * for grayscale output the green channel is used. * * background must be supplied when an alpha channel must be removed from a * single byte color-mapped output format, in other words if: * * 1) The original format from png_image_begin_read_from_* had * PNG_FORMAT_FLAG_ALPHA set. * 2) The format set by the application does not. * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and * PNG_FORMAT_FLAG_LINEAR *not* set. * * For linear output removing the alpha channel is always done by compositing * on black and background is ignored. * * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE. * image->colormap_entries will be updated to the actual number of entries * written to the colormap; this may be less than the original value. */ PNG_EXPORT(238, void, png_image_free, (png_imagep image)); /* Free any data allocated by libpng in image->opaque, setting the pointer to * NULL. May be called at any time after the structure is initialized. */ #endif /* SIMPLIFIED_READ */ #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED /* WRITE APIS * ---------- * For write you must initialize a png_image structure to describe the image to * be written. To do this use memset to set the whole structure to 0 then * initialize fields describing your image. * * version: must be set to PNG_IMAGE_VERSION * opaque: must be initialized to NULL * width: image width in pixels * height: image height in rows * format: the format of the data (image and color-map) you wish to write * flags: set to 0 unless one of the defined flags applies; set * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB * values do not correspond to the colors in sRGB. * colormap_entries: set to the number of entries in the color-map (0 to 256) */ #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image, const char *file, int convert_to_8bit, const void *buffer, png_int_32 row_stride, const void *colormap)); /* Write the image to the named file. */ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file, int convert_to_8_bit, const void *buffer, png_int_32 row_stride, const void *colormap)); /* Write the image to the given (FILE*). */ #endif /* SIMPLIFIED_WRITE_STDIO */ /* With all write APIs if image is in one of the linear formats with 16-bit * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG * gamma encoded according to the sRGB specification, otherwise a 16-bit linear * encoded PNG file is written. * * With color-mapped data formats the colormap parameter point to a color-map * with at least image->colormap_entries encoded in the specified format. If * the format is linear the written PNG color-map will be converted to sRGB * regardless of the convert_to_8_bit flag. * * With all APIs row_stride is handled as in the read APIs - it is the spacing * from one row to the next in component sized units (1 or 2 bytes) and if * negative indicates a bottom-up row layout in the buffer. If row_stride is * zero, libpng will calculate it for you from the image width and number of * channels. * * Note that the write API does not support interlacing, sub-8-bit pixels or * most ancillary chunks. If you need to write text chunks (e.g. for copyright * notices) you need to use one of the other APIs. */ PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory, png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit, const void *buffer, png_int_32 row_stride, const void *colormap)); /* Write the image to the given memory buffer. The function both writes the * whole PNG data stream to *memory and updates *memory_bytes with the count * of bytes written. * * 'memory' may be NULL. In this case *memory_bytes is not read however on * success the number of bytes which would have been written will still be * stored in *memory_bytes. On failure *memory_bytes will contain 0. * * If 'memory' is not NULL it must point to memory[*memory_bytes] of * writeable memory. * * If the function returns success memory[*memory_bytes] (if 'memory' is not * NULL) contains the written PNG data. *memory_bytes will always be less * than or equal to the original value. * * If the function returns false and *memory_bytes was not changed an error * occurred during write. If *memory_bytes was changed, or is not 0 if * 'memory' was NULL, the write would have succeeded but for the memory * buffer being too small. *memory_bytes contains the required number of * bytes and will be bigger that the original value. */ #define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\ row_stride, colormap)\ png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\ row_stride, colormap) /* Return the amount of memory in 'size' required to compress this image. * The png_image structure 'image' must be filled in as in the above * function and must not be changed before the actual write call, the buffer * and all other parameters must also be identical to that in the final * write call. The 'size' variable need not be initialized. * * NOTE: the macro returns true/false, if false is returned 'size' will be * set to zero and the write failed and probably will fail if tried again. */ /* You can pre-allocate the buffer by making sure it is of sufficient size * regardless of the amount of compression achieved. The buffer size will * always be bigger than the original image and it will never be filled. The * following macros are provided to assist in allocating the buffer. */ #define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height) /* The number of uncompressed bytes in the PNG byte encoding of the image; * uncompressing the PNG IDAT data will give this number of bytes. * * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this * macro can because of the extra bytes used in the PNG byte encoding. You * need to avoid this macro if your image size approaches 2^30 in width or * height. The same goes for the remainder of these macros; they all produce * bigger numbers than the actual in-memory image size. */ #ifndef PNG_ZLIB_MAX_SIZE # define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U) /* An upper bound on the number of compressed bytes given 'b' uncompressed * bytes. This is based on deflateBounds() in zlib; different * implementations of zlib compression may conceivably produce more data so * if your zlib implementation is not zlib itself redefine this macro * appropriately. */ #endif #define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\ PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image)) /* An upper bound on the size of the data in the PNG IDAT chunks. */ #define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\ ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\ (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\ 12U+3U*(image).colormap_entries/*PLTE data*/+\ (((image).format&PNG_FORMAT_FLAG_ALPHA)?\ 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\ 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size)) /* A helper for the following macro; if your compiler cannot handle the * following macro use this one with the result of * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most * compilers should handle this just fine.) */ #define PNG_IMAGE_PNG_SIZE_MAX(image)\ PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image)) /* An upper bound on the total length of the PNG data stream for 'image'. * The result is of type png_alloc_size_t, on 32-bit systems this may * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will * run out of buffer space but return a corrected size which should work. */ #endif /* SIMPLIFIED_WRITE */ /******************************************************************************* * END OF SIMPLIFIED API ******************************************************************************/ #endif /* SIMPLIFIED_{READ|WRITE} */ /******************************************************************************* * Section 6: IMPLEMENTATION OPTIONS ******************************************************************************* * * Support for arbitrary implementation-specific optimizations. The API allows * particular options to be turned on or off. 'Option' is the number of the * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given * by the PNG_OPTION_ defines below. * * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions, * are detected at run time, however sometimes it may be impossible * to do this in user mode, in which case it is necessary to discover * the capabilities in an OS specific way. Such capabilities are * listed here when libpng has support for them and must be turned * ON by the application if present. * * SOFTWARE: sometimes software optimizations actually result in performance * decrease on some architectures or systems, or with some sets of * PNG images. 'Software' options allow such optimizations to be * selected at run time. */ #ifdef PNG_SET_OPTION_SUPPORTED #ifdef PNG_ARM_NEON_API_SUPPORTED # define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */ #endif #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */ #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */ #ifdef PNG_MIPS_MSA_API_SUPPORTED # define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */ #endif #define PNG_IGNORE_ADLER32 8 #ifdef PNG_POWERPC_VSX_API_SUPPORTED # define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions supported */ #endif #define PNG_OPTION_NEXT 12 /* Next option - numbers must be even */ /* Return values: NOTE: there are four values and 'off' is *not* zero */ #define PNG_OPTION_UNSET 0 /* Unset - defaults to off */ #define PNG_OPTION_INVALID 1 /* Option number out of range */ #define PNG_OPTION_OFF 2 #define PNG_OPTION_ON 3 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option, int onoff)); #endif /* SET_OPTION */ /******************************************************************************* * END OF HARDWARE AND SOFTWARE OPTIONS ******************************************************************************/ /* Maintainer: Put new public prototypes here ^, in libpng.3, in project * defs, and in scripts/symbols.def. */ /* The last ordinal number (this is the *last* one already used; the next * one to use is one more than this.) */ #ifdef PNG_EXPORT_LAST_ORDINAL PNG_EXPORT_LAST_ORDINAL(249); #endif #ifdef __cplusplus } #endif #endif /* PNG_VERSION_INFO_ONLY */ /* Do not put anything past this line */ #endif /* PNG_H */
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