/thirdparty/libpng/png.h
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1/* png.h - header file for PNG reference library 2 * 3 * libpng version 1.2.7 - September 12, 2004 4 * Copyright (c) 1998-2004 Glenn Randers-Pehrson 5 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) 6 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) 7 * 8 * Authors and maintainers: 9 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat 10 * libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger 11 * libpng versions 0.97, January 1998, through 1.2.7 - September 12, 2004: Glenn 12 * See also "Contributing Authors", below. 13 * 14 * Note about libpng version numbers: 15 * 16 * Due to various miscommunications, unforeseen code incompatibilities 17 * and occasional factors outside the authors' control, version numbering 18 * on the library has not always been consistent and straightforward. 19 * The following table summarizes matters since version 0.89c, which was 20 * the first widely used release: 21 * 22 * source png.h png.h shared-lib 23 * version string int version 24 * ------- ------ ----- ---------- 25 * 0.89c "1.0 beta 3" 0.89 89 1.0.89 26 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90] 27 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95] 28 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96] 29 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97] 30 * 0.97c 0.97 97 2.0.97 31 * 0.98 0.98 98 2.0.98 32 * 0.99 0.99 98 2.0.99 33 * 0.99a-m 0.99 99 2.0.99 34 * 1.00 1.00 100 2.1.0 [100 should be 10000] 35 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000] 36 * 1.0.1 png.h string is 10001 2.1.0 37 * 1.0.1a-e identical to the 10002 from here on, the shared library 38 * 1.0.2 source version) 10002 is 2.V where V is the source code 39 * 1.0.2a-b 10003 version, except as noted. 40 * 1.0.3 10003 41 * 1.0.3a-d 10004 42 * 1.0.4 10004 43 * 1.0.4a-f 10005 44 * 1.0.5 (+ 2 patches) 10005 45 * 1.0.5a-d 10006 46 * 1.0.5e-r 10100 (not source compatible) 47 * 1.0.5s-v 10006 (not binary compatible) 48 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible) 49 * 1.0.6d-f 10007 (still binary incompatible) 50 * 1.0.6g 10007 51 * 1.0.6h 10007 10.6h (testing xy.z so-numbering) 52 * 1.0.6i 10007 10.6i 53 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0) 54 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible) 55 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible) 56 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible) 57 * 1.0.7 1 10007 (still compatible) 58 * 1.0.8beta1-4 1 10008 2.1.0.8beta1-4 59 * 1.0.8rc1 1 10008 2.1.0.8rc1 60 * 1.0.8 1 10008 2.1.0.8 61 * 1.0.9beta1-6 1 10009 2.1.0.9beta1-6 62 * 1.0.9rc1 1 10009 2.1.0.9rc1 63 * 1.0.9beta7-10 1 10009 2.1.0.9beta7-10 64 * 1.0.9rc2 1 10009 2.1.0.9rc2 65 * 1.0.9 1 10009 2.1.0.9 66 * 1.0.10beta1 1 10010 2.1.0.10beta1 67 * 1.0.10rc1 1 10010 2.1.0.10rc1 68 * 1.0.10 1 10010 2.1.0.10 69 * 1.0.11beta1-3 1 10011 2.1.0.11beta1-3 70 * 1.0.11rc1 1 10011 2.1.0.11rc1 71 * 1.0.11 1 10011 2.1.0.11 72 * 1.0.12beta1-2 2 10012 2.1.0.12beta1-2 73 * 1.0.12rc1 2 10012 2.1.0.12rc1 74 * 1.0.12 2 10012 2.1.0.12 75 * 1.1.0a-f - 10100 2.1.1.0a-f (branch abandoned) 76 * 1.2.0beta1-2 2 10200 2.1.2.0beta1-2 77 * 1.2.0beta3-5 3 10200 3.1.2.0beta3-5 78 * 1.2.0rc1 3 10200 3.1.2.0rc1 79 * 1.2.0 3 10200 3.1.2.0 80 * 1.2.1beta1-4 3 10201 3.1.2.1beta1-4 81 * 1.2.1rc1-2 3 10201 3.1.2.1rc1-2 82 * 1.2.1 3 10201 3.1.2.1 83 * 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6 84 * 1.0.13beta1 10 10013 10.so.0.1.0.13beta1 85 * 1.0.13rc1 10 10013 10.so.0.1.0.13rc1 86 * 1.2.2rc1 12 10202 12.so.0.1.2.2rc1 87 * 1.0.13 10 10013 10.so.0.1.0.13 88 * 1.2.2 12 10202 12.so.0.1.2.2 89 * 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6 90 * 1.2.3 12 10203 12.so.0.1.2.3 91 * 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3 92 * 1.0.14rc1 13 10014 10.so.0.1.0.14rc1 93 * 1.2.4rc1 13 10204 12.so.0.1.2.4rc1 94 * 1.0.14 10 10014 10.so.0.1.0.14 95 * 1.2.4 13 10204 12.so.0.1.2.4 96 * 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2 97 * 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3 98 * 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3 99 * 1.0.15 10 10015 10.so.0.1.0.15 100 * 1.2.5 13 10205 12.so.0.1.2.5 101 * 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4 102 * 1.0.16 10 10016 10.so.0.1.0.16 103 * 1.2.6 13 10206 12.so.0.1.2.6 104 * 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2 105 * 1.0.17rc1 10 10017 12.so.0.1.0.17rc1 106 * 1.2.7rc1 13 10207 12.so.0.1.2.7rc1 107 * 1.0.17 10 10017 12.so.0.1.0.17 108 * 1.2.7 13 10207 12.so.0.1.2.7 109 * 110 * Henceforth the source version will match the shared-library major 111 * and minor numbers; the shared-library major version number will be 112 * used for changes in backward compatibility, as it is intended. The 113 * PNG_LIBPNG_VER macro, which is not used within libpng but is available 114 * for applications, is an unsigned integer of the form xyyzz corresponding 115 * to the source version x.y.z (leading zeros in y and z). Beta versions 116 * were given the previous public release number plus a letter, until 117 * version 1.0.6j; from then on they were given the upcoming public 118 * release number plus "betaNN" or "rcN". 119 * 120 * Binary incompatibility exists only when applications make direct access 121 * to the info_ptr or png_ptr members through png.h, and the compiled 122 * application is loaded with a different version of the library. 123 * 124 * DLLNUM will change each time there are forward or backward changes 125 * in binary compatibility (e.g., when a new feature is added). 126 * 127 * See libpng.txt or libpng.3 for more information. The PNG specification 128 * is available as a W3C Recommendation and as an ISO Specification, 129 * <http://www.w3.org/TR/2003/REC-PNG-20031110/ 130 */ 131 132/* 133 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE: 134 * 135 * If you modify libpng you may insert additional notices immediately following 136 * this sentence. 137 * 138 * libpng versions 1.2.6, August 15, 2004, through 1.2.7, September 12, 2004, are 139 * Copyright (c) 2004 Glenn Randers-Pehrson, and are 140 * distributed according to the same disclaimer and license as libpng-1.2.5 141 * with the following individual added to the list of Contributing Authors: 142 * 143 * Cosmin Truta 144 * 145 * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are 146 * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are 147 * distributed according to the same disclaimer and license as libpng-1.0.6 148 * with the following individuals added to the list of Contributing Authors: 149 * 150 * Simon-Pierre Cadieux 151 * Eric S. Raymond 152 * Gilles Vollant 153 * 154 * and with the following additions to the disclaimer: 155 * 156 * There is no warranty against interference with your enjoyment of the 157 * library or against infringement. There is no warranty that our 158 * efforts or the library will fulfill any of your particular purposes 159 * or needs. This library is provided with all faults, and the entire 160 * risk of satisfactory quality, performance, accuracy, and effort is with 161 * the user. 162 * 163 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are 164 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are 165 * distributed according to the same disclaimer and license as libpng-0.96, 166 * with the following individuals added to the list of Contributing Authors: 167 * 168 * Tom Lane 169 * Glenn Randers-Pehrson 170 * Willem van Schaik 171 * 172 * libpng versions 0.89, June 1996, through 0.96, May 1997, are 173 * Copyright (c) 1996, 1997 Andreas Dilger 174 * Distributed according to the same disclaimer and license as libpng-0.88, 175 * with the following individuals added to the list of Contributing Authors: 176 * 177 * John Bowler 178 * Kevin Bracey 179 * Sam Bushell 180 * Magnus Holmgren 181 * Greg Roelofs 182 * Tom Tanner 183 * 184 * libpng versions 0.5, May 1995, through 0.88, January 1996, are 185 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. 186 * 187 * For the purposes of this copyright and license, "Contributing Authors" 188 * is defined as the following set of individuals: 189 * 190 * Andreas Dilger 191 * Dave Martindale 192 * Guy Eric Schalnat 193 * Paul Schmidt 194 * Tim Wegner 195 * 196 * The PNG Reference Library is supplied "AS IS". The Contributing Authors 197 * and Group 42, Inc. disclaim all warranties, expressed or implied, 198 * including, without limitation, the warranties of merchantability and of 199 * fitness for any purpose. The Contributing Authors and Group 42, Inc. 200 * assume no liability for direct, indirect, incidental, special, exemplary, 201 * or consequential damages, which may result from the use of the PNG 202 * Reference Library, even if advised of the possibility of such damage. 203 * 204 * Permission is hereby granted to use, copy, modify, and distribute this 205 * source code, or portions hereof, for any purpose, without fee, subject 206 * to the following restrictions: 207 * 208 * 1. The origin of this source code must not be misrepresented. 209 * 210 * 2. Altered versions must be plainly marked as such and 211 * must not be misrepresented as being the original source. 212 * 213 * 3. This Copyright notice may not be removed or altered from 214 * any source or altered source distribution. 215 * 216 * The Contributing Authors and Group 42, Inc. specifically permit, without 217 * fee, and encourage the use of this source code as a component to 218 * supporting the PNG file format in commercial products. If you use this 219 * source code in a product, acknowledgment is not required but would be 220 * appreciated. 221 */ 222 223/* 224 * A "png_get_copyright" function is available, for convenient use in "about" 225 * boxes and the like: 226 * 227 * printf("%s",png_get_copyright(NULL)); 228 * 229 * Also, the PNG logo (in PNG format, of course) is supplied in the 230 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31). 231 */ 232 233/* 234 * Libpng is OSI Certified Open Source Software. OSI Certified is a 235 * certification mark of the Open Source Initiative. 236 */ 237 238/* 239 * The contributing authors would like to thank all those who helped 240 * with testing, bug fixes, and patience. This wouldn't have been 241 * possible without all of you. 242 * 243 * Thanks to Frank J. T. Wojcik for helping with the documentation. 244 */ 245 246/* 247 * Y2K compliance in libpng: 248 * ========================= 249 * 250 * September 12, 2004 251 * 252 * Since the PNG Development group is an ad-hoc body, we can't make 253 * an official declaration. 254 * 255 * This is your unofficial assurance that libpng from version 0.71 and 256 * upward through 1.2.7 are Y2K compliant. It is my belief that earlier 257 * versions were also Y2K compliant. 258 * 259 * Libpng only has three year fields. One is a 2-byte unsigned integer 260 * that will hold years up to 65535. The other two hold the date in text 261 * format, and will hold years up to 9999. 262 * 263 * The integer is 264 * "png_uint_16 year" in png_time_struct. 265 * 266 * The strings are 267 * "png_charp time_buffer" in png_struct and 268 * "near_time_buffer", which is a local character string in png.c. 269 * 270 * There are seven time-related functions: 271 * png.c: png_convert_to_rfc_1123() in png.c 272 * (formerly png_convert_to_rfc_1152() in error) 273 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c 274 * png_convert_from_time_t() in pngwrite.c 275 * png_get_tIME() in pngget.c 276 * png_handle_tIME() in pngrutil.c, called in pngread.c 277 * png_set_tIME() in pngset.c 278 * png_write_tIME() in pngwutil.c, called in pngwrite.c 279 * 280 * All handle dates properly in a Y2K environment. The 281 * png_convert_from_time_t() function calls gmtime() to convert from system 282 * clock time, which returns (year - 1900), which we properly convert to 283 * the full 4-digit year. There is a possibility that applications using 284 * libpng are not passing 4-digit years into the png_convert_to_rfc_1123() 285 * function, or that they are incorrectly passing only a 2-digit year 286 * instead of "year - 1900" into the png_convert_from_struct_tm() function, 287 * but this is not under our control. The libpng documentation has always 288 * stated that it works with 4-digit years, and the APIs have been 289 * documented as such. 290 * 291 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned 292 * integer to hold the year, and can hold years as large as 65535. 293 * 294 * zlib, upon which libpng depends, is also Y2K compliant. It contains 295 * no date-related code. 296 * 297 * Glenn Randers-Pehrson 298 * libpng maintainer 299 * PNG Development Group 300 */ 301 302#ifndef PNG_H 303#define PNG_H 304 305/* This is not the place to learn how to use libpng. The file libpng.txt 306 * describes how to use libpng, and the file example.c summarizes it 307 * with some code on which to build. This file is useful for looking 308 * at the actual function definitions and structure components. 309 */ 310 311/* Version information for png.h - this should match the version in png.c */ 312#define PNG_LIBPNG_VER_STRING "1.2.7" 313#define PNG_HEADER_VERSION_STRING \ 314 " libpng version 1.2.7 - September 12, 2004 (header)\n" 315 316#define PNG_LIBPNG_VER_SONUM 0 317#define PNG_LIBPNG_VER_DLLNUM %DLLNUM% 318 319/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */ 320#define PNG_LIBPNG_VER_MAJOR 1 321#define PNG_LIBPNG_VER_MINOR 2 322#define PNG_LIBPNG_VER_RELEASE 7 323/* This should match the numeric part of the final component of 324 * PNG_LIBPNG_VER_STRING, omitting any leading zero: */ 325 326#define PNG_LIBPNG_VER_BUILD 0 327 328#define PNG_LIBPNG_BUILD_ALPHA 1 329#define PNG_LIBPNG_BUILD_BETA 2 330#define PNG_LIBPNG_BUILD_RC 3 331#define PNG_LIBPNG_BUILD_STABLE 4 332#define PNG_LIBPNG_BUILD_TYPEMASK 7 333#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with STABLE only */ 334#define PNG_LIBPNG_BUILD_TYPE 4 335 336/* Careful here. At one time, Guy wanted to use 082, but that would be octal. 337 * We must not include leading zeros. 338 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only 339 * version 1.0.0 was mis-numbered 100 instead of 10000). From 340 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release */ 341#define PNG_LIBPNG_VER 10207 /* 1.2.7 */ 342 343#ifndef PNG_VERSION_INFO_ONLY 344 345/* include the compression library's header */ 346#include "zlib.h" 347 348/* include all user configurable info, including optional assembler routines */ 349#include "pngconf.h" 350 351/* Inhibit C++ name-mangling for libpng functions but not for system calls. */ 352#ifdef __cplusplus 353extern "C" { 354#endif /* __cplusplus */ 355 356/* This file is arranged in several sections. The first section contains 357 * structure and type definitions. The second section contains the external 358 * library functions, while the third has the internal library functions, 359 * which applications aren't expected to use directly. 360 */ 361 362#ifndef PNG_NO_TYPECAST_NULL 363#define int_p_NULL (int *)NULL 364#define png_bytep_NULL (png_bytep)NULL 365#define png_bytepp_NULL (png_bytepp)NULL 366#define png_doublep_NULL (png_doublep)NULL 367#define png_error_ptr_NULL (png_error_ptr)NULL 368#define png_flush_ptr_NULL (png_flush_ptr)NULL 369#define png_free_ptr_NULL (png_free_ptr)NULL 370#define png_infopp_NULL (png_infopp)NULL 371#define png_malloc_ptr_NULL (png_malloc_ptr)NULL 372#define png_read_status_ptr_NULL (png_read_status_ptr)NULL 373#define png_rw_ptr_NULL (png_rw_ptr)NULL 374#define png_structp_NULL (png_structp)NULL 375#define png_uint_16p_NULL (png_uint_16p)NULL 376#define png_voidp_NULL (png_voidp)NULL 377#define png_write_status_ptr_NULL (png_write_status_ptr)NULL 378#else 379#define int_p_NULL NULL 380#define png_bytep_NULL NULL 381#define png_bytepp_NULL NULL 382#define png_doublep_NULL NULL 383#define png_error_ptr_NULL NULL 384#define png_flush_ptr_NULL NULL 385#define png_free_ptr_NULL NULL 386#define png_infopp_NULL NULL 387#define png_malloc_ptr_NULL NULL 388#define png_read_status_ptr_NULL NULL 389#define png_rw_ptr_NULL NULL 390#define png_structp_NULL NULL 391#define png_uint_16p_NULL NULL 392#define png_voidp_NULL NULL 393#define png_write_status_ptr_NULL NULL 394#endif 395 396/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */ 397#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN) 398/* Version information for C files, stored in png.c. This had better match 399 * the version above. 400 */ 401#ifdef PNG_USE_GLOBAL_ARRAYS 402PNG_EXPORT_VAR (const char) png_libpng_ver[18]; 403 /* need room for 99.99.99beta99z */ 404#else 405#define png_libpng_ver png_get_header_ver(NULL) 406#endif 407 408#ifdef PNG_USE_GLOBAL_ARRAYS 409/* This was removed in version 1.0.5c */ 410/* Structures to facilitate easy interlacing. See png.c for more details */ 411PNG_EXPORT_VAR (const int FARDATA) png_pass_start[7]; 412PNG_EXPORT_VAR (const int FARDATA) png_pass_inc[7]; 413PNG_EXPORT_VAR (const int FARDATA) png_pass_ystart[7]; 414PNG_EXPORT_VAR (const int FARDATA) png_pass_yinc[7]; 415PNG_EXPORT_VAR (const int FARDATA) png_pass_mask[7]; 416PNG_EXPORT_VAR (const int FARDATA) png_pass_dsp_mask[7]; 417#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW 418PNG_EXPORT_VAR (const int FARDATA) png_pass_width[7]; 419#endif 420/* This isn't currently used. If you need it, see png.c for more details. 421PNG_EXPORT_VAR (const int FARDATA) png_pass_height[7]; 422*/ 423#endif 424 425#endif /* PNG_NO_EXTERN */ 426 427/* Three color definitions. The order of the red, green, and blue, (and the 428 * exact size) is not important, although the size of the fields need to 429 * be png_byte or png_uint_16 (as defined below). 430 */ 431typedef struct png_color_struct 432{ 433 png_byte red; 434 png_byte green; 435 png_byte blue; 436} png_color; 437typedef png_color FAR * png_colorp; 438typedef png_color FAR * FAR * png_colorpp; 439 440typedef struct png_color_16_struct 441{ 442 png_byte index; /* used for palette files */ 443 png_uint_16 red; /* for use in red green blue files */ 444 png_uint_16 green; 445 png_uint_16 blue; 446 png_uint_16 gray; /* for use in grayscale files */ 447} png_color_16; 448typedef png_color_16 FAR * png_color_16p; 449typedef png_color_16 FAR * FAR * png_color_16pp; 450 451typedef struct png_color_8_struct 452{ 453 png_byte red; /* for use in red green blue files */ 454 png_byte green; 455 png_byte blue; 456 png_byte gray; /* for use in grayscale files */ 457 png_byte alpha; /* for alpha channel files */ 458} png_color_8; 459typedef png_color_8 FAR * png_color_8p; 460typedef png_color_8 FAR * FAR * png_color_8pp; 461 462/* 463 * The following two structures are used for the in-core representation 464 * of sPLT chunks. 465 */ 466typedef struct png_sPLT_entry_struct 467{ 468 png_uint_16 red; 469 png_uint_16 green; 470 png_uint_16 blue; 471 png_uint_16 alpha; 472 png_uint_16 frequency; 473} png_sPLT_entry; 474typedef png_sPLT_entry FAR * png_sPLT_entryp; 475typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp; 476 477/* When the depth of the sPLT palette is 8 bits, the color and alpha samples 478 * occupy the LSB of their respective members, and the MSB of each member 479 * is zero-filled. The frequency member always occupies the full 16 bits. 480 */ 481 482typedef struct png_sPLT_struct 483{ 484 png_charp name; /* palette name */ 485 png_byte depth; /* depth of palette samples */ 486 png_sPLT_entryp entries; /* palette entries */ 487 png_int_32 nentries; /* number of palette entries */ 488} png_sPLT_t; 489typedef png_sPLT_t FAR * png_sPLT_tp; 490typedef png_sPLT_t FAR * FAR * png_sPLT_tpp; 491 492#ifdef PNG_TEXT_SUPPORTED 493/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file, 494 * and whether that contents is compressed or not. The "key" field 495 * points to a regular zero-terminated C string. The "text", "lang", and 496 * "lang_key" fields can be regular C strings, empty strings, or NULL pointers. 497 * However, the * structure returned by png_get_text() will always contain 498 * regular zero-terminated C strings (possibly empty), never NULL pointers, 499 * so they can be safely used in printf() and other string-handling functions. 500 */ 501typedef struct png_text_struct 502{ 503 int compression; /* compression value: 504 -1: tEXt, none 505 0: zTXt, deflate 506 1: iTXt, none 507 2: iTXt, deflate */ 508 png_charp key; /* keyword, 1-79 character description of "text" */ 509 png_charp text; /* comment, may be an empty string (ie "") 510 or a NULL pointer */ 511 png_size_t text_length; /* length of the text string */ 512#ifdef PNG_iTXt_SUPPORTED 513 png_size_t itxt_length; /* length of the itxt string */ 514 png_charp lang; /* language code, 0-79 characters 515 or a NULL pointer */ 516 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more 517 chars or a NULL pointer */ 518#endif 519} png_text; 520typedef png_text FAR * png_textp; 521typedef png_text FAR * FAR * png_textpp; 522#endif 523 524/* Supported compression types for text in PNG files (tEXt, and zTXt). 525 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */ 526#define PNG_TEXT_COMPRESSION_NONE_WR -3 527#define PNG_TEXT_COMPRESSION_zTXt_WR -2 528#define PNG_TEXT_COMPRESSION_NONE -1 529#define PNG_TEXT_COMPRESSION_zTXt 0 530#define PNG_ITXT_COMPRESSION_NONE 1 531#define PNG_ITXT_COMPRESSION_zTXt 2 532#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */ 533 534/* png_time is a way to hold the time in an machine independent way. 535 * Two conversions are provided, both from time_t and struct tm. There 536 * is no portable way to convert to either of these structures, as far 537 * as I know. If you know of a portable way, send it to me. As a side 538 * note - PNG has always been Year 2000 compliant! 539 */ 540typedef struct png_time_struct 541{ 542 png_uint_16 year; /* full year, as in, 1995 */ 543 png_byte month; /* month of year, 1 - 12 */ 544 png_byte day; /* day of month, 1 - 31 */ 545 png_byte hour; /* hour of day, 0 - 23 */ 546 png_byte minute; /* minute of hour, 0 - 59 */ 547 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */ 548} png_time; 549typedef png_time FAR * png_timep; 550typedef png_time FAR * FAR * png_timepp; 551 552#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) 553/* png_unknown_chunk is a structure to hold queued chunks for which there is 554 * no specific support. The idea is that we can use this to queue 555 * up private chunks for output even though the library doesn't actually 556 * know about their semantics. 557 */ 558typedef struct png_unknown_chunk_t 559{ 560 png_byte name[5]; 561 png_byte *data; 562 png_size_t size; 563 564 /* libpng-using applications should NOT directly modify this byte. */ 565 png_byte location; /* mode of operation at read time */ 566} 567png_unknown_chunk; 568typedef png_unknown_chunk FAR * png_unknown_chunkp; 569typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp; 570#endif 571 572/* png_info is a structure that holds the information in a PNG file so 573 * that the application can find out the characteristics of the image. 574 * If you are reading the file, this structure will tell you what is 575 * in the PNG file. If you are writing the file, fill in the information 576 * you want to put into the PNG file, then call png_write_info(). 577 * The names chosen should be very close to the PNG specification, so 578 * consult that document for information about the meaning of each field. 579 * 580 * With libpng < 0.95, it was only possible to directly set and read the 581 * the values in the png_info_struct, which meant that the contents and 582 * order of the values had to remain fixed. With libpng 0.95 and later, 583 * however, there are now functions that abstract the contents of 584 * png_info_struct from the application, so this makes it easier to use 585 * libpng with dynamic libraries, and even makes it possible to use 586 * libraries that don't have all of the libpng ancillary chunk-handing 587 * functionality. 588 * 589 * In any case, the order of the parameters in png_info_struct should NOT 590 * be changed for as long as possible to keep compatibility with applications 591 * that use the old direct-access method with png_info_struct. 592 * 593 * The following members may have allocated storage attached that should be 594 * cleaned up before the structure is discarded: palette, trans, text, 595 * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile, 596 * splt_palettes, scal_unit, row_pointers, and unknowns. By default, these 597 * are automatically freed when the info structure is deallocated, if they were 598 * allocated internally by libpng. This behavior can be changed by means 599 * of the png_data_freer() function. 600 * 601 * More allocation details: all the chunk-reading functions that 602 * change these members go through the corresponding png_set_* 603 * functions. A function to clear these members is available: see 604 * png_free_data(). The png_set_* functions do not depend on being 605 * able to point info structure members to any of the storage they are 606 * passed (they make their own copies), EXCEPT that the png_set_text 607 * functions use the same storage passed to them in the text_ptr or 608 * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns 609 * functions do not make their own copies. 610 */ 611typedef struct png_info_struct 612{ 613 /* the following are necessary for every PNG file */ 614 png_uint_32 width; /* width of image in pixels (from IHDR) */ 615 png_uint_32 height; /* height of image in pixels (from IHDR) */ 616 png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */ 617 png_uint_32 rowbytes; /* bytes needed to hold an untransformed row */ 618 png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */ 619 png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */ 620 png_uint_16 num_trans; /* number of transparent palette color (tRNS) */ 621 png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */ 622 png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */ 623 /* The following three should have been named *_method not *_type */ 624 png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */ 625 png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */ 626 png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */ 627 628 /* The following is informational only on read, and not used on writes. */ 629 png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */ 630 png_byte pixel_depth; /* number of bits per pixel */ 631 png_byte spare_byte; /* to align the data, and for future use */ 632 png_byte signature[8]; /* magic bytes read by libpng from start of file */ 633 634 /* The rest of the data is optional. If you are reading, check the 635 * valid field to see if the information in these are valid. If you 636 * are writing, set the valid field to those chunks you want written, 637 * and initialize the appropriate fields below. 638 */ 639 640#if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) 641 /* The gAMA chunk describes the gamma characteristics of the system 642 * on which the image was created, normally in the range [1.0, 2.5]. 643 * Data is valid if (valid & PNG_INFO_gAMA) is non-zero. 644 */ 645 float gamma; /* gamma value of image, if (valid & PNG_INFO_gAMA) */ 646#endif 647 648#if defined(PNG_sRGB_SUPPORTED) 649 /* GR-P, 0.96a */ 650 /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */ 651 png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */ 652#endif 653 654#if defined(PNG_TEXT_SUPPORTED) 655 /* The tEXt, and zTXt chunks contain human-readable textual data in 656 * uncompressed, compressed, and optionally compressed forms, respectively. 657 * The data in "text" is an array of pointers to uncompressed, 658 * null-terminated C strings. Each chunk has a keyword that describes the 659 * textual data contained in that chunk. Keywords are not required to be 660 * unique, and the text string may be empty. Any number of text chunks may 661 * be in an image. 662 */ 663 int num_text; /* number of comments read/to write */ 664 int max_text; /* current size of text array */ 665 png_textp text; /* array of comments read/to write */ 666#endif /* PNG_TEXT_SUPPORTED */ 667 668#if defined(PNG_tIME_SUPPORTED) 669 /* The tIME chunk holds the last time the displayed image data was 670 * modified. See the png_time struct for the contents of this struct. 671 */ 672 png_time mod_time; 673#endif 674 675#if defined(PNG_sBIT_SUPPORTED) 676 /* The sBIT chunk specifies the number of significant high-order bits 677 * in the pixel data. Values are in the range [1, bit_depth], and are 678 * only specified for the channels in the pixel data. The contents of 679 * the low-order bits is not specified. Data is valid if 680 * (valid & PNG_INFO_sBIT) is non-zero. 681 */ 682 png_color_8 sig_bit; /* significant bits in color channels */ 683#endif 684 685#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \ 686defined(PNG_READ_BACKGROUND_SUPPORTED) 687 /* The tRNS chunk supplies transparency data for paletted images and 688 * other image types that don't need a full alpha channel. There are 689 * "num_trans" transparency values for a paletted image, stored in the 690 * same order as the palette colors, starting from index 0. Values 691 * for the data are in the range [0, 255], ranging from fully transparent 692 * to fully opaque, respectively. For non-paletted images, there is a 693 * single color specified that should be treated as fully transparent. 694 * Data is valid if (valid & PNG_INFO_tRNS) is non-zero. 695 */ 696 png_bytep trans; /* transparent values for paletted image */ 697 png_color_16 trans_values; /* transparent color for non-palette image */ 698#endif 699 700#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) 701 /* The bKGD chunk gives the suggested image background color if the 702 * display program does not have its own background color and the image 703 * is needs to composited onto a background before display. The colors 704 * in "background" are normally in the same color space/depth as the 705 * pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero. 706 */ 707 png_color_16 background; 708#endif 709 710#if defined(PNG_oFFs_SUPPORTED) 711 /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards 712 * and downwards from the top-left corner of the display, page, or other 713 * application-specific co-ordinate space. See the PNG_OFFSET_ defines 714 * below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero. 715 */ 716 png_int_32 x_offset; /* x offset on page */ 717 png_int_32 y_offset; /* y offset on page */ 718 png_byte offset_unit_type; /* offset units type */ 719#endif 720 721#if defined(PNG_pHYs_SUPPORTED) 722 /* The pHYs chunk gives the physical pixel density of the image for 723 * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_ 724 * defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero. 725 */ 726 png_uint_32 x_pixels_per_unit; /* horizontal pixel density */ 727 png_uint_32 y_pixels_per_unit; /* vertical pixel density */ 728 png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */ 729#endif 730 731#if defined(PNG_hIST_SUPPORTED) 732 /* The hIST chunk contains the relative frequency or importance of the 733 * various palette entries, so that a viewer can intelligently select a 734 * reduced-color palette, if required. Data is an array of "num_palette" 735 * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST) 736 * is non-zero. 737 */ 738 png_uint_16p hist; 739#endif 740 741#ifdef PNG_cHRM_SUPPORTED 742 /* The cHRM chunk describes the CIE color characteristics of the monitor 743 * on which the PNG was created. This data allows the viewer to do gamut 744 * mapping of the input image to ensure that the viewer sees the same 745 * colors in the image as the creator. Values are in the range 746 * [0.0, 0.8]. Data valid if (valid & PNG_INFO_cHRM) non-zero. 747 */ 748#ifdef PNG_FLOATING_POINT_SUPPORTED 749 float x_white; 750 float y_white; 751 float x_red; 752 float y_red; 753 float x_green; 754 float y_green; 755 float x_blue; 756 float y_blue; 757#endif 758#endif 759 760#if defined(PNG_pCAL_SUPPORTED) 761 /* The pCAL chunk describes a transformation between the stored pixel 762 * values and original physical data values used to create the image. 763 * The integer range [0, 2^bit_depth - 1] maps to the floating-point 764 * range given by [pcal_X0, pcal_X1], and are further transformed by a 765 * (possibly non-linear) transformation function given by "pcal_type" 766 * and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_ 767 * defines below, and the PNG-Group's PNG extensions document for a 768 * complete description of the transformations and how they should be 769 * implemented, and for a description of the ASCII parameter strings. 770 * Data values are valid if (valid & PNG_INFO_pCAL) non-zero. 771 */ 772 png_charp pcal_purpose; /* pCAL chunk description string */ 773 png_int_32 pcal_X0; /* minimum value */ 774 png_int_32 pcal_X1; /* maximum value */ 775 png_charp pcal_units; /* Latin-1 string giving physical units */ 776 png_charpp pcal_params; /* ASCII strings containing parameter values */ 777 png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */ 778 png_byte pcal_nparams; /* number of parameters given in pcal_params */ 779#endif 780 781/* New members added in libpng-1.0.6 */ 782#ifdef PNG_FREE_ME_SUPPORTED 783 png_uint_32 free_me; /* flags items libpng is responsible for freeing */ 784#endif 785 786#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) 787 /* storage for unknown chunks that the library doesn't recognize. */ 788 png_unknown_chunkp unknown_chunks; 789 png_size_t unknown_chunks_num; 790#endif 791 792#if defined(PNG_iCCP_SUPPORTED) 793 /* iCCP chunk data. */ 794 png_charp iccp_name; /* profile name */ 795 png_charp iccp_profile; /* International Color Consortium profile data */ 796 /* Note to maintainer: should be png_bytep */ 797 png_uint_32 iccp_proflen; /* ICC profile data length */ 798 png_byte iccp_compression; /* Always zero */ 799#endif 800 801#if defined(PNG_sPLT_SUPPORTED) 802 /* data on sPLT chunks (there may be more than one). */ 803 png_sPLT_tp splt_palettes; 804 png_uint_32 splt_palettes_num; 805#endif 806 807#if defined(PNG_sCAL_SUPPORTED) 808 /* The sCAL chunk describes the actual physical dimensions of the 809 * subject matter of the graphic. The chunk contains a unit specification 810 * a byte value, and two ASCII strings representing floating-point 811 * values. The values are width and height corresponsing to one pixel 812 * in the image. This external representation is converted to double 813 * here. Data values are valid if (valid & PNG_INFO_sCAL) is non-zero. 814 */ 815 png_byte scal_unit; /* unit of physical scale */ 816#ifdef PNG_FLOATING_POINT_SUPPORTED 817 double scal_pixel_width; /* width of one pixel */ 818 double scal_pixel_height; /* height of one pixel */ 819#endif 820#ifdef PNG_FIXED_POINT_SUPPORTED 821 png_charp scal_s_width; /* string containing height */ 822 png_charp scal_s_height; /* string containing width */ 823#endif 824#endif 825 826#if defined(PNG_INFO_IMAGE_SUPPORTED) 827 /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) non-zero */ 828 /* Data valid if (valid & PNG_INFO_IDAT) non-zero */ 829 png_bytepp row_pointers; /* the image bits */ 830#endif 831 832#if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED) 833 png_fixed_point int_gamma; /* gamma of image, if (valid & PNG_INFO_gAMA) */ 834#endif 835 836#if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED) 837 png_fixed_point int_x_white; 838 png_fixed_point int_y_white; 839 png_fixed_point int_x_red; 840 png_fixed_point int_y_red; 841 png_fixed_point int_x_green; 842 png_fixed_point int_y_green; 843 png_fixed_point int_x_blue; 844 png_fixed_point int_y_blue; 845#endif 846 847} png_info; 848 849typedef png_info FAR * png_infop; 850typedef png_info FAR * FAR * png_infopp; 851 852/* Maximum positive integer used in PNG is (2^31)-1 */ 853#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL) 854#define PNG_UINT_32_MAX (~((png_uint_32)0)) 855#define PNG_SIZE_MAX (~((png_size_t)0)) 856/* PNG_MAX_UINT is deprecated; use PNG_UINT_31_MAX instead. */ 857#define PNG_MAX_UINT PNG_UINT_31_MAX 858 859/* These describe the color_type field in png_info. */ 860/* color type masks */ 861#define PNG_COLOR_MASK_PALETTE 1 862#define PNG_COLOR_MASK_COLOR 2 863#define PNG_COLOR_MASK_ALPHA 4 864 865/* color types. Note that not all combinations are legal */ 866#define PNG_COLOR_TYPE_GRAY 0 867#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE) 868#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR) 869#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA) 870#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA) 871/* aliases */ 872#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA 873#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA 874 875/* This is for compression type. PNG 1.0-1.2 only define the single type. */ 876#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */ 877#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE 878 879/* This is for filter type. PNG 1.0-1.2 only define the single type. */ 880#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */ 881#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */ 882#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE 883 884/* These are for the interlacing type. These values should NOT be changed. */ 885#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */ 886#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */ 887#define PNG_INTERLACE_LAST 2 /* Not a valid value */ 888 889/* These are for the oFFs chunk. These values should NOT be changed. */ 890#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */ 891#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */ 892#define PNG_OFFSET_LAST 2 /* Not a valid value */ 893 894/* These are for the pCAL chunk. These values should NOT be changed. */ 895#define PNG_EQUATION_LINEAR 0 /* Linear transformation */ 896#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */ 897#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */ 898#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */ 899#define PNG_EQUATION_LAST 4 /* Not a valid value */ 900 901/* These are for the sCAL chunk. These values should NOT be changed. */ 902#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */ 903#define PNG_SCALE_METER 1 /* meters per pixel */ 904#define PNG_SCALE_RADIAN 2 /* radians per pixel */ 905#define PNG_SCALE_LAST 3 /* Not a valid value */ 906 907/* These are for the pHYs chunk. These values should NOT be changed. */ 908#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */ 909#define PNG_RESOLUTION_METER 1 /* pixels/meter */ 910#define PNG_RESOLUTION_LAST 2 /* Not a valid value */ 911 912/* These are for the sRGB chunk. These values should NOT be changed. */ 913#define PNG_sRGB_INTENT_PERCEPTUAL 0 914#define PNG_sRGB_INTENT_RELATIVE 1 915#define PNG_sRGB_INTENT_SATURATION 2 916#define PNG_sRGB_INTENT_ABSOLUTE 3 917#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */ 918 919/* This is for text chunks */ 920#define PNG_KEYWORD_MAX_LENGTH 79 921 922/* Maximum number of entries in PLTE/sPLT/tRNS arrays */ 923#define PNG_MAX_PALETTE_LENGTH 256 924 925/* These determine if an ancillary chunk's data has been successfully read 926 * from the PNG header, or if the application has filled in the corresponding 927 * data in the info_struct to be written into the output file. The values 928 * of the PNG_INFO_<chunk> defines should NOT be changed. 929 */ 930#define PNG_INFO_gAMA 0x0001 931#define PNG_INFO_sBIT 0x0002 932#define PNG_INFO_cHRM 0x0004 933#define PNG_INFO_PLTE 0x0008 934#define PNG_INFO_tRNS 0x0010 935#define PNG_INFO_bKGD 0x0020 936#define PNG_INFO_hIST 0x0040 937#define PNG_INFO_pHYs 0x0080 938#define PNG_INFO_oFFs 0x0100 939#define PNG_INFO_tIME 0x0200 940#define PNG_INFO_pCAL 0x0400 941#define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */ 942#define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */ 943#define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */ 944#define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */ 945#define PNG_INFO_IDAT 0x8000L /* ESR, 1.0.6 */ 946 947/* This is used for the transformation routines, as some of them 948 * change these values for the row. It also should enable using 949 * the routines for other purposes. 950 */ 951typedef struct png_row_info_struct 952{ 953 png_uint_32 width; /* width of row */ 954 png_uint_32 rowbytes; /* number of bytes in row */ 955 png_byte color_type; /* color type of row */ 956 png_byte bit_depth; /* bit depth of row */ 957 png_byte channels; /* number of channels (1, 2, 3, or 4) */ 958 png_byte pixel_depth; /* bits per pixel (depth * channels) */ 959} png_row_info; 960 961typedef png_row_info FAR * png_row_infop; 962typedef png_row_info FAR * FAR * png_row_infopp; 963 964/* These are the function types for the I/O functions and for the functions 965 * that allow the user to override the default I/O functions with his or her 966 * own. The png_error_ptr type should match that of user-supplied warning 967 * and error functions, while the png_rw_ptr type should match that of the 968 * user read/write data functions. 969 */ 970typedef struct png_struct_def png_struct; 971typedef png_struct FAR * png_structp; 972 973typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp)); 974typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t)); 975typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp)); 976typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32, 977 int)); 978typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32, 979 int)); 980 981#ifdef PNG_PROGRESSIVE_READ_SUPPORTED 982typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp, png_infop)); 983typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop)); 984typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep, 985 png_uint_32, int)); 986#endif 987 988#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ 989 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \ 990 defined(PNG_LEGACY_SUPPORTED) 991typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp, 992 png_row_infop, png_bytep)); 993#endif 994 995#if defined(PNG_USER_CHUNKS_SUPPORTED) 996typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp)); 997#endif 998#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) 999typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp)); 1000#endif 1001 1002/* Transform masks for the high-level interface */ 1003#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */ 1004#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */ 1005#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */ 1006#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */ 1007#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */ 1008#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */ 1009#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */ 1010#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */ 1011#define PNG_TRANSFORM_BGR 0x0080 /* read and write */ 1012#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */ 1013#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */ 1014#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */ 1015#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* WRITE only */ 1016 1017/* Flags for MNG supported features */ 1018#define PNG_FLAG_MNG_EMPTY_PLTE 0x01 1019#define PNG_FLAG_MNG_FILTER_64 0x04 1020#define PNG_ALL_MNG_FEATURES 0x05 1021 1022typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t)); 1023typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp)); 1024 1025/* The structure that holds the information to read and write PNG files. 1026 * The only people who need to care about what is inside of this are the 1027 * people who will be modifying the library for their own special needs. 1028 * It should NOT be accessed directly by an application, except to store 1029 * the jmp_buf. 1030 */ 1031 1032struct png_struct_def 1033{ 1034#ifdef PNG_SETJMP_SUPPORTED 1035 jmp_buf jmpbuf; /* used in png_error */ 1036#endif 1037 png_error_ptr error_fn; /* function for printing errors and aborting */ 1038 png_error_ptr warning_fn; /* function for printing warnings */ 1039 png_voidp error_ptr; /* user supplied struct for error functions */ 1040 png_rw_ptr write_data_fn; /* function for writing output data */ 1041 png_rw_ptr read_data_fn; /* function for reading input data */ 1042 png_voidp io_ptr; /* ptr to application struct for I/O functions */ 1043 1044#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) 1045 png_user_transform_ptr read_user_transform_fn; /* user read transform */ 1046#endif 1047 1048#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) 1049 png_user_transform_ptr write_user_transform_fn; /* user write transform */ 1050#endif 1051 1052/* These were added in libpng-1.0.2 */ 1053#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) 1054#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ 1055 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) 1056 png_voidp user_transform_ptr; /* user supplied struct for user transform */ 1057 png_byte user_transform_depth; /* bit depth of user transformed pixels */ 1058 png_byte user_transform_channels; /* channels in user transformed pixels */ 1059#endif 1060#endif 1061 1062 png_uint_32 mode; /* tells us where we are in the PNG file */ 1063 png_uint_32 flags; /* flags indicating various things to libpng */ 1064 png_uint_32 transformations; /* which transformations to perform */ 1065 1066 z_stream zstream; /* pointer to decompression structure (below) */ 1067 png_bytep zbuf; /* buffer for zlib */ 1068 png_size_t zbuf_size; /* size of zbuf */ 1069 int zlib_level; /* holds zlib compression level */ 1070 int zlib_method; /* holds zlib compression method */ 1071 int zlib_window_bits; /* holds zlib compression window bits */ 1072 int zlib_mem_level; /* holds zlib compression memory level */ 1073 int zlib_strategy; /* holds zlib compression strategy */ 1074 1075 png_uint_32 width; /* width of image in pixels */ 1076 png_uint_32 height; /* height of image in pixels */ 1077 png_uint_32 num_rows; /* number of rows in current pass */ 1078 png_uint_32 usr_width; /* width of row at start of write */ 1079 png_uint_32 rowbytes; /* size of row in bytes */ 1080 png_uint_32 irowbytes; /* size of current interlaced row in bytes */ 1081 png_uint_32 iwidth; /* width of current interlaced row in pixels */ 1082 png_uint_32 row_number; /* current row in interlace pass */ 1083 png_bytep prev_row; /* buffer to save previous (unfiltered) row */ 1084 png_bytep row_buf; /* buffer to save current (unfiltered) row */ 1085 png_bytep sub_row; /* buffer to save "sub" row when filtering */ 1086 png_bytep up_row; /* buffer to save "up" row when filtering */ 1087 png_bytep avg_row; /* buffer to save "avg" row when filtering */ 1088 png_bytep paeth_row; /* buffer to save "Paeth" row when filtering */ 1089 png_row_info row_info; /* used for transformation routines */ 1090 1091 png_uint_32 idat_size; /* current IDAT size for read */ 1092 png_uint_32 crc; /* current chunk CRC value */ 1093 png_colorp palette; /* palette from the input file */ 1094 png_uint_16 num_palette; /* number of color entries in palette */ 1095 png_uint_16 num_trans; /* number of transparency values */ 1096 png_byte chunk_name[5]; /* null-terminated name of current chunk */ 1097 png_byte compression; /* file compression type (always 0) */ 1098 png_byte filter; /* file filter …
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