1 2 /* png.h - header file for PNG reference library 3 * 4 * libpng version 1.7.0beta90, August 28, 2017 5 * 6 * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson 7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) 8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) 9 * 10 * This code is released under the libpng license (See LICENSE, below) 11 * 12 * Authors and maintainers: 13 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat 14 * libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger 15 * libpng versions 0.97, January 1998, through 1.7.0beta90, August 28, 2017: 16 * Glenn Randers-Pehrson. 17 * See also "Contributing Authors", below. 18 */ 19 20 /* 21 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE: 22 * 23 * If you modify libpng you may insert additional notices immediately following 24 * this sentence. 25 * 26 * This code is released under the libpng license. 27 * 28 * libpng versions 1.0.7, July 1, 2000 through 1.7.0beta90, August 28, 2017 are 29 * Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are 30 * derived from libpng-1.0.6, and are distributed according to the same 31 * disclaimer and license as libpng-1.0.6 with the following individuals 32 * added to the list of Contributing Authors: 33 * 34 * Simon-Pierre Cadieux 35 * Eric S. Raymond 36 * Mans Rullgard 37 * Cosmin Truta 38 * Gilles Vollant 39 * James Yu 40 * 41 * and with the following additions to the disclaimer: 42 * 43 * There is no warranty against interference with your enjoyment of the 44 * library or against infringement. There is no warranty that our 45 * efforts or the library will fulfill any of your particular purposes 46 * or needs. This library is provided with all faults, and the entire 47 * risk of satisfactory quality, performance, accuracy, and effort is with 48 * the user. 49 * 50 * Some files in the "contrib" directory and some configure-generated 51 * files that are distributed with libpng have other copyright owners and 52 * are released under other open source licenses. 53 * 54 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are 55 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from 56 * libpng-0.96, and are distributed according to the same disclaimer and 57 * license as libpng-0.96, with the following individuals added to the list 58 * of Contributing Authors: 59 * 60 * Tom Lane 61 * Glenn Randers-Pehrson 62 * Willem van Schaik 63 * 64 * libpng versions 0.89, June 1996, through 0.96, May 1997, are 65 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88, 66 * and are distributed according to the same disclaimer and license as 67 * libpng-0.88, with the following individuals added to the list of 68 * Contributing Authors: 69 * 70 * John Bowler 71 * Kevin Bracey 72 * Sam Bushell 73 * Magnus Holmgren 74 * Greg Roelofs 75 * Tom Tanner 76 * 77 * Some files in the "scripts" directory have other copyright owners 78 * but are released under this license. 79 * 80 * libpng versions 0.5, May 1995, through 0.88, January 1996, are 81 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc. 82 * 83 * For the purposes of this copyright and license, "Contributing Authors" 84 * is defined as the following set of individuals: 85 * 86 * Andreas Dilger 87 * Dave Martindale 88 * Guy Eric Schalnat 89 * Paul Schmidt 90 * Tim Wegner 91 * 92 * The PNG Reference Library is supplied "AS IS". The Contributing Authors 93 * and Group 42, Inc. disclaim all warranties, expressed or implied, 94 * including, without limitation, the warranties of merchantability and of 95 * fitness for any purpose. The Contributing Authors and Group 42, Inc. 96 * assume no liability for direct, indirect, incidental, special, exemplary, 97 * or consequential damages, which may result from the use of the PNG 98 * Reference Library, even if advised of the possibility of such damage. 99 * 100 * Permission is hereby granted to use, copy, modify, and distribute this 101 * source code, or portions hereof, for any purpose, without fee, subject 102 * to the following restrictions: 103 * 104 * 1. The origin of this source code must not be misrepresented. 105 * 106 * 2. Altered versions must be plainly marked as such and must not 107 * be misrepresented as being the original source. 108 * 109 * 3. This Copyright notice may not be removed or altered from any 110 * source or altered source distribution. 111 * 112 * The Contributing Authors and Group 42, Inc. specifically permit, without 113 * fee, and encourage the use of this source code as a component to 114 * supporting the PNG file format in commercial products. If you use this 115 * source code in a product, acknowledgment is not required but would be 116 * appreciated. 117 * 118 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE. 119 * 120 * TRADEMARK: 121 * 122 * The name "libpng" has not been registered by the Copyright owner 123 * as a trademark in any jurisdiction. However, because libpng has 124 * been distributed and maintained world-wide, continually since 1995, 125 * the Copyright owner claims "common-law trademark protection" in any 126 * jurisdiction where common-law trademark is recognized. 127 * 128 * OSI CERTIFICATION: 129 * 130 * Libpng is OSI Certified Open Source Software. OSI Certified Open Source is 131 * a certification mark of the Open Source Initiative. OSI has not addressed 132 * the additional disclaimers inserted at version 1.0.7. 133 * 134 * EXPORT CONTROL: 135 * 136 * The Copyright owner believes that the Export Control Classification 137 * Number (ECCN) for libpng is EAR99, which means not subject to export 138 * controls or International Traffic in Arms Regulations (ITAR) because 139 * it is open source, publicly available software, that does not contain 140 * any encryption software. See the EAR, paragraphs 734.3(b)(3) and 141 * 734.7(b). 142 */ 143 144 /* 145 * A "png_get_copyright" function is available, for convenient use in "about" 146 * boxes and the like: 147 * 148 * printf("%s", png_get_copyright(NULL)); 149 * 150 * Also, the PNG logo (in PNG format, of course) is supplied in the 151 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31). 152 */ 153 154 /* 155 * The contributing authors would like to thank all those who helped 156 * with testing, bug fixes, and patience. This wouldn't have been 157 * possible without all of you. 158 * 159 * Thanks to Frank J. T. Wojcik for helping with the documentation. 160 */ 161 162 /* Note about libpng version numbers: 163 * 164 * Due to various miscommunications, unforeseen code incompatibilities 165 * and occasional factors outside the authors' control, version numbering 166 * on the library has not always been consistent and straightforward. 167 * The following table summarizes matters since version 0.89c, which was 168 * the first widely used release: 169 * 170 * source png.h png.h shared-lib 171 * version string int version 172 * ------- ------ ----- ---------- 173 * 0.89c "1.0 beta 3" 0.89 89 1.0.89 174 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90] 175 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95] 176 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96] 177 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97] 178 * 0.97c 0.97 97 2.0.97 179 * 0.98 0.98 98 2.0.98 180 * 0.99 0.99 98 2.0.99 181 * 0.99a-m 0.99 99 2.0.99 182 * 1.00 1.00 100 2.1.0 [100 should be 10000] 183 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000] 184 * 1.0.1 png.h string is 10001 2.1.0 185 * 1.0.1a-e identical to the 10002 from here on, the shared library 186 * 1.0.2 source version) 10002 is 2.V where V is the source code 187 * 1.0.2a-b 10003 version, except as noted. 188 * 1.0.3 10003 189 * 1.0.3a-d 10004 190 * 1.0.4 10004 191 * 1.0.4a-f 10005 192 * 1.0.5 (+ 2 patches) 10005 193 * 1.0.5a-d 10006 194 * 1.0.5e-r 10100 (not source compatible) 195 * 1.0.5s-v 10006 (not binary compatible) 196 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible) 197 * 1.0.6d-f 10007 (still binary incompatible) 198 * 1.0.6g 10007 199 * 1.0.6h 10007 10.6h (testing xy.z so-numbering) 200 * 1.0.6i 10007 10.6i 201 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0) 202 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible) 203 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible) 204 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible) 205 * 1.0.7 1 10007 (still compatible) 206 * ... 207 * 1.0.19 10 10019 10.so.0.19[.0] 208 * ... 209 * 1.2.56 13 10253 12.so.0.53[.0] 210 * ... 211 * 1.5.27 15 10523 15.so.15.23[.0] 212 * ... 213 * 1.6.22 16 10622 16.so.16.22[.0] 214 * ... 215 * 1.7.0alpha01-10 17 10700 17.so.17.0[.0] 216 * 1.7.0beta01-84 17 10700 17.so.17.0[.0] 217 * 218 * Henceforth the source version will match the shared-library major 219 * and minor numbers; the shared-library major version number will be 220 * used for changes in backward compatibility, as it is intended. The 221 * PNG_LIBPNG_VER macro, which is not used within libpng but is available 222 * for applications, is an unsigned integer of the form xyyzz corresponding 223 * to the source version x.y.z (leading zeros in y and z). Beta versions 224 * were given the previous public release number plus a letter, until 225 * version 1.0.6j; from then on they were given the upcoming public 226 * release number plus "betaNN" or "rcNN". 227 * 228 * Binary incompatibility exists only when applications make direct access 229 * to the info_ptr or png_ptr members through png.h, and the compiled 230 * application is loaded with a different version of the library. 231 * 232 * DLLNUM will change each time there are forward or backward changes 233 * in binary compatibility (e.g., when a new feature is added). 234 * 235 * See libpng.txt or libpng.3 for more information. The PNG specification 236 * is available as a W3C Recommendation and as an ISO Specification, 237 * <https://www.w3.org/TR/2003/REC-PNG-20031110/ 238 */ 239 240 /* 241 * Y2K compliance in libpng: 242 * ========================= 243 * 244 * August 28, 2017 245 * 246 * Since the PNG Development group is an ad-hoc body, we can't make 247 * an official declaration. 248 * 249 * This is your unofficial assurance that libpng from version 0.71 and 250 * upward through 1.7.0beta90 are Y2K compliant. It is my belief that 251 * earlier versions were also Y2K compliant. 252 * 253 * Libpng only has two year fields. One is a 2-byte unsigned integer 254 * that will hold years up to 65535. The other, which is deprecated, 255 * holds the date in text format, and will hold years up to 9999. 256 * 257 * The integer is 258 * "png_uint_16 year" in png_time_struct. 259 * 260 * The string is 261 * "char time_buffer[29]" in png_struct. This is no longer used 262 * in libpng-1.6.x and will be removed from libpng-1.7.0. 263 * 264 * There are seven time-related functions: 265 * png.c: png_convert_to_rfc_1123_buffer() in png.c 266 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and 267 * png_convert_to_rfc_1152() in error prior to libpng-0.98) 268 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c 269 * png_convert_from_time_t() in pngwrite.c 270 * png_get_tIME() in pngget.c 271 * png_handle_tIME() in pngrutil.c, called in pngread.c 272 * png_set_tIME() in pngset.c 273 * png_write_tIME() in pngwutil.c, called in pngwrite.c 274 * 275 * All handle dates properly in a Y2K environment. The 276 * png_convert_from_time_t() function calls gmtime() to convert from system 277 * clock time, which returns (year - 1900), which we properly convert to 278 * the full 4-digit year. There is a possibility that libpng applications 279 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer() 280 * function, or that they are incorrectly passing only a 2-digit year 281 * instead of "year - 1900" into the png_convert_from_struct_tm() function, 282 * but this is not under our control. The libpng documentation has always 283 * stated that it works with 4-digit years, and the APIs have been 284 * documented as such. 285 * 286 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned 287 * integer to hold the year, and can hold years as large as 65535. 288 * 289 * zlib, upon which libpng depends, is also Y2K compliant. It contains 290 * no date-related code. 291 * 292 * Glenn Randers-Pehrson 293 * libpng maintainer 294 * PNG Development Group 295 */ 296 297 #ifndef PNG_H 298 #define PNG_H 299 300 /* This is not the place to learn how to use libpng. The file libpng-manual.txt 301 * describes how to use libpng, and the file example.c summarizes it 302 * with some code on which to build. This file is useful for looking 303 * at the actual function definitions and structure components. If that 304 * file has been stripped from your copy of libpng, you can find it at 305 * <http://www.libpng.org/pub/png/libpng-manual.txt> 306 * 307 * If you just need to read a PNG file and don't want to read the documentation 308 * skip to the end of this file and read the section entitled 'simplified API'. 309 */ 310 311 /* Version information for png.h - this should match the version in png.c */ 312 #define PNG_LIBPNG_VER_STRING "1.7.0beta90" 313 #define PNG_HEADER_VERSION_STRING " libpng version 1.7.0beta90 - August 28, 2017\n" 314 315 #define PNG_LIBPNG_VER_SONUM 17 316 #define PNG_LIBPNG_VER_DLLNUM 17 317 318 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */ 319 #define PNG_LIBPNG_VER_MAJOR 1 320 #define PNG_LIBPNG_VER_MINOR 7 321 #define PNG_LIBPNG_VER_RELEASE 0 322 323 /* This should match the numeric part of the final component of 324 * PNG_LIBPNG_VER_STRING, omitting any leading zero: 325 */ 326 327 #define PNG_LIBPNG_VER_BUILD 90 328 329 /* Release Status */ 330 #define PNG_LIBPNG_BUILD_ALPHA 1 331 #define PNG_LIBPNG_BUILD_BETA 2 332 #define PNG_LIBPNG_BUILD_RC 3 333 #define PNG_LIBPNG_BUILD_STABLE 4 334 #define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7 335 336 /* Release-Specific Flags */ 337 #define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with 338 PNG_LIBPNG_BUILD_STABLE only */ 339 #define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with 340 PNG_LIBPNG_BUILD_SPECIAL */ 341 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with 342 PNG_LIBPNG_BUILD_PRIVATE */ 343 344 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA 345 346 /* Careful here. At one time, Guy wanted to use 082, but that would be octal. 347 * We must not include leading zeros. 348 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only 349 * version 1.0.0 was mis-numbered 100 instead of 10000). From 350 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release 351 */ 352 #define PNG_LIBPNG_VER 10700 /* 1.7.0 */ 353 354 /* Library configuration: these options cannot be changed after 355 * the library has been built. 356 */ 357 #ifndef PNGLCONF_H 358 /* If pnglibconf.h is missing, you can 359 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h 360 */ 361 # include "pnglibconf.h" 362 #endif 363 364 #ifndef PNG_VERSION_INFO_ONLY 365 /* Machine specific configuration. */ 366 # include "pngconf.h" 367 #endif 368 369 /* 370 * Added at libpng-1.2.8 371 * 372 * Ref MSDN: Private as priority over Special 373 * VS_FF_PRIVATEBUILD File *was not* built using standard release 374 * procedures. If this value is given, the StringFileInfo block must 375 * contain a PrivateBuild string. 376 * 377 * VS_FF_SPECIALBUILD File *was* built by the original company using 378 * standard release procedures but is a variation of the standard 379 * file of the same version number. If this value is given, the 380 * StringFileInfo block must contain a SpecialBuild string. 381 */ 382 383 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */ 384 # define PNG_LIBPNG_BUILD_TYPE \ 385 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE) 386 #else 387 # ifdef PNG_LIBPNG_SPECIALBUILD 388 # define PNG_LIBPNG_BUILD_TYPE \ 389 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL) 390 # else 391 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE) 392 # endif 393 #endif 394 395 #ifndef PNG_VERSION_INFO_ONLY 396 397 /* Version information for C files, stored in png.c. This had better match 398 * the version above. 399 */ 400 #define png_libpng_ver png_get_header_ver(NULL) 401 402 /* This file is arranged in several sections: 403 * 404 * 1. ISO-PNG constants and definitions; values defined by PNG and not specific 405 * to the libpng API. 406 * 2. Any configuration options that can be specified by for the application 407 * code when it is built. (Build time configuration is in pnglibconf.h) 408 * 3. Type definitions (base types are defined in pngconf.h), structure 409 * definitions. 410 * 4. Exported library functions. 411 * 5. Simplified API. 412 * 6. Implementation options 413 * 414 * The library source code has additional files (principally pngpriv.h) that 415 * allow configuration of the library. 416 */ 417 418 /* Section 1: ISO PNG constants and macros. */ 419 420 /* ISO-PNG defines byte encodings for 16 and 32-bit unsigned values and 32-bit 421 * signed values. The macros PNG_U16, PNG_U32 and PNG_S32 return values of type 422 * (png_uint_16), (png_uint_32) and (png_int_32) which are target machine 423 * specific representations of these values, using the types defined in 424 * pngconf.h. The macros take two or four byte values in the order in which 425 * they would occur in a PNG stream. 426 * 427 * These macros must return compile time constants if passed constant values - 428 * machine specific implementations are not permitted. These macros are used by 429 * default in the API functions/macros png_get_uint_16, png_get_uint_32, 430 * png_get_uint_31 and png_get_int_32 declared below: these functions or macros 431 * are the correct places for machine specific implementations (such as hardware 432 * specific instructions.) 433 * 434 * The macros defined here are generic and intended to give maximum flexibility 435 * in implementation to the compiler; only PNG_S32 contains a sequence point, 436 * there are no side effects and the expressions used permit the maximum 437 * parallelization (relevant because the four bytes may be loaded in parallel.) 438 */ 439 #define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2)) 440 441 #define PNG_U16(b1, b2) ((png_uint_16)/*SAFE*/PNG_u2(b1, b2)) 442 #define PNG_U32(b1, b2, b3, b4)\ 443 (((png_uint_32)/*SAFE*/PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4)) 444 445 /* ISO-PNG states that signed 32-bit values are stored in two's complement 446 * format. There is no guarantee that (png_int_32) is exactly 32 bits, so the 447 * following macro tests for a negative number and generates the machine format 448 * directly by portable arithmetic operations. The cost is that the argument 449 * 'b1' is evaluated twice. 450 * 451 * NOTE: the 0x7fffffffU BIC is there to ensure that potential overflow in the 452 * cast does not occur. This fixes the case where 1's complement machines could 453 * be forced into an overflow by an invalid value in the stream and, therefore, 454 * potentially raise an arithmetic exception; the invalid value is converted to 455 * 0 and any resultant problems will be caught later in the libpng checking. 456 */ 457 #define PNG_S32(b1, b2, b3, b4) ((b1) & 0x80\ 458 ? -(png_int_32)(((PNG_U32(b1, b2, b3, b4)^0xffffffffU)+1U)&0x7fffffffU)\ 459 : (png_int_32)PNG_U32(b1, b2, b3, b4)) 460 461 /* Constants for known chunk types. 462 * 463 * MAINTAINERS: If you need to add a chunk, define the name here. 464 * For historical reasons these constants have the form png_<name>; i.e. 465 * the prefix is lower case. Please use decimal values as the parameters to 466 * match the ISO PNG specification and to avoid relying on the C locale 467 * interpretation of character values. Please keep the list sorted. 468 * 469 * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk 470 * type. In fact the specification does not express chunk types this way, 471 * however using a 32-bit value means that the chunk type can be read from the 472 * stream using exactly the same code as used for a 32-bit unsigned value and 473 * can be examined far more efficiently (using one arithmetic compare). 474 * 475 * Prior to 1.5.6 the chunk type constants were expressed as C strings. The 476 * libpng API still uses strings for 'unknown' chunks and a macro, 477 * PNG_STRING_FROM_CHUNK, allows a string to be generated if required. Notice 478 * that for portable code numeric values must still be used; the string "IHDR" 479 * is not portable and neither is PNG_U32('I', 'H', 'D', 'R'). 480 * 481 * In 1.7.0 the definitions were made public in png.h to avoid having to 482 * duplicate the same definitions in application code. 483 * 484 * SOURCE: http://www.libpng.org/pub/png/spec/register/ 485 * "Register of PNG Public Chunks and Keywords, version 1.4.6" 486 * "Extensions to the PNG Specification, version 1.4.0" 487 */ 488 #define png_IDAT PNG_U32( 73, 68, 65, 84) 489 #define png_IEND PNG_U32( 73, 69, 78, 68) 490 #define png_IHDR PNG_U32( 73, 72, 68, 82) 491 #define png_PLTE PNG_U32( 80, 76, 84, 69) 492 #define png_bKGD PNG_U32( 98, 75, 71, 68) 493 #define png_cHRM PNG_U32( 99, 72, 82, 77) 494 #define png_dSIG PNG_U32(100, 83, 73, 71) /* separate spec */ 495 #define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */ 496 #define png_gAMA PNG_U32(103, 65, 77, 65) 497 #define png_gIFg PNG_U32(103, 73, 70, 103) 498 #define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */ 499 #define png_gIFx PNG_U32(103, 73, 70, 120) 500 #define png_hIST PNG_U32(104, 73, 83, 84) 501 #define png_iCCP PNG_U32(105, 67, 67, 80) 502 #define png_iTXt PNG_U32(105, 84, 88, 116) 503 #define png_oFFs PNG_U32(111, 70, 70, 115) 504 #define png_pCAL PNG_U32(112, 67, 65, 76) 505 #define png_pHYs PNG_U32(112, 72, 89, 115) 506 #define png_sBIT PNG_U32(115, 66, 73, 84) 507 #define png_sCAL PNG_U32(115, 67, 65, 76) 508 #define png_sPLT PNG_U32(115, 80, 76, 84) 509 #define png_sRGB PNG_U32(115, 82, 71, 66) 510 #define png_sTER PNG_U32(115, 84, 69, 82) 511 #define png_tEXt PNG_U32(116, 69, 88, 116) 512 #define png_tIME PNG_U32(116, 73, 77, 69) 513 #define png_tRNS PNG_U32(116, 82, 78, 83) 514 #define png_zTXt PNG_U32(122, 84, 88, 116) 515 516 /* The following will work on (signed char*) strings, whereas the PNG_U32 macro 517 * used directory would fail on top-bit-set values because of the sign 518 * extension. 519 */ 520 #define PNG_CHUNK_FROM_STRING(s)\ 521 PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3]) 522 523 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is 524 * signed and the argument is a (char[]) This macro will fail miserably on 525 * systems where (char) is more than 8 bits. 526 */ 527 #define PNG_STRING_FROM_CHUNK(s,c)\ 528 (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \ 529 ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\ 530 ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \ 531 ((char*)(s))[3]=(char)((c & 0xff))) 532 533 /* Do the same but terminate with a null character. */ 534 #define PNG_CSTRING_FROM_CHUNK(s,c)\ 535 (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0) 536 537 /* Test on flag values as defined in the spec (section 5.4): */ 538 #define PNG_CHUNK_ANCILLARY(c) (1 & ((c) >> 29)) 539 #define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c)) 540 #define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21)) 541 #define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13)) 542 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5)) 543 544 /* Section 2: run time configuration 545 * See pnglibconf.h for build time configuration 546 * 547 * Run time configuration allows the application to choose between 548 * implementations of certain arithmetic APIs. The default is set 549 * at build time and recorded in pnglibconf.h, but it is safe to 550 * override these (and only these) settings. Note that this won't 551 * change what the library does, only application code, and the 552 * settings can (and probably should) be made on a per-file basis 553 * by setting the #defines before including png.h 554 * 555 * Use macros to read integers from PNG data or use the exported 556 * functions? 557 * PNG_USE_READ_MACROS: use the macros (see below) Note that 558 * the macros evaluate their argument multiple times. 559 * PNG_NO_USE_READ_MACROS: call the relevant library function. 560 * 561 * Use the alternative algorithm for compositing alpha samples that 562 * does not use division? 563 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division' 564 * algorithm. 565 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm. 566 * 567 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is 568 * false? 569 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error 570 * APIs to png_warning. 571 * Otherwise the calls are mapped to png_error. 572 */ 573 574 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */ 575 #ifdef __cplusplus 576 extern "C" { 577 #endif /* __cplusplus */ 578 579 /* Section 3: type definitions, including structures and compile time 580 * constants. 581 * See pngconf.h for base types that vary by machine/system 582 */ 583 584 /* This triggers a compiler error in png.c, if png.c and png.h 585 * do not agree upon the version number. 586 */ 587 typedef char* png_libpng_version_1_7_0beta90; 588 589 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info. 590 * 591 * png_struct is the cache of information used while reading or writing a single 592 * PNG file. One of these is always required, although the simplified API 593 * (below) hides the creation and destruction of it. 594 */ 595 typedef struct png_struct_def png_struct; 596 typedef const png_struct * png_const_structp; 597 typedef png_struct * png_structp; 598 typedef png_struct * * png_structpp; 599 600 /* png_info contains information read from or to be written to a PNG file. One 601 * or more of these must exist while reading or creating a PNG file. The 602 * information is not used by libpng during read but is used to control what 603 * gets written when a PNG file is created. "png_get_" function calls read 604 * information during read and "png_set_" functions calls write information 605 * when creating a PNG. 606 * been moved into a separate header file that is not accessible to 607 * applications. Read libpng-manual.txt or libpng.3 for more info. 608 */ 609 typedef struct png_info_def png_info; 610 typedef png_info * png_infop; 611 typedef const png_info * png_const_infop; 612 typedef png_info * * png_infopp; 613 614 /* Types with names ending 'p' are pointer types. The corresponding types with 615 * names ending 'rp' are identical pointer types except that the pointer is 616 * marked 'restrict', which means that it is the only pointer to the object 617 * passed to the function. Applications should not use the 'restrict' types; 618 * it is always valid to pass 'p' to a pointer with a function argument of the 619 * corresponding 'rp' type. Different compilers have different rules with 620 * regard to type matching in the presence of 'restrict'. For backward 621 * compatibility libpng callbacks never have 'restrict' in their parameters and, 622 * consequentially, writing portable application code is extremely difficult if 623 * an attempt is made to use 'restrict'. 624 */ 625 typedef png_struct * PNG_RESTRICT png_structrp; 626 typedef const png_struct * PNG_RESTRICT png_const_structrp; 627 typedef png_info * PNG_RESTRICT png_inforp; 628 typedef const png_info * PNG_RESTRICT png_const_inforp; 629 630 /* Three color definitions. The order of the red, green, and blue, (and the 631 * exact size) is not important, although the size of the fields need to 632 * be png_byte or png_uint_16 (as defined below). 633 */ 634 typedef struct png_color_struct 635 { 636 png_byte red; 637 png_byte green; 638 png_byte blue; 639 } png_color; 640 typedef png_color * png_colorp; 641 typedef const png_color * png_const_colorp; 642 typedef png_color * * png_colorpp; 643 644 typedef struct png_color_16_struct 645 { 646 png_byte index; /* used for palette files */ 647 png_uint_16 red; /* for use in red green blue files */ 648 png_uint_16 green; 649 png_uint_16 blue; 650 png_uint_16 gray; /* for use in grayscale files */ 651 } png_color_16; 652 typedef png_color_16 * png_color_16p; 653 typedef const png_color_16 * png_const_color_16p; 654 typedef png_color_16 * * png_color_16pp; 655 656 typedef struct png_color_8_struct 657 { 658 png_byte red; /* for use in red green blue files */ 659 png_byte green; 660 png_byte blue; 661 png_byte gray; /* for use in grayscale files */ 662 png_byte alpha; /* for alpha channel files */ 663 } png_color_8; 664 typedef png_color_8 * png_color_8p; 665 typedef const png_color_8 * png_const_color_8p; 666 typedef png_color_8 * * png_color_8pp; 667 668 /* 669 * The following two structures are used for the in-core representation 670 * of sPLT chunks. 671 */ 672 typedef struct png_sPLT_entry_struct 673 { 674 png_uint_16 red; 675 png_uint_16 green; 676 png_uint_16 blue; 677 png_uint_16 alpha; 678 png_uint_16 frequency; 679 } png_sPLT_entry; 680 typedef png_sPLT_entry * png_sPLT_entryp; 681 typedef const png_sPLT_entry * png_const_sPLT_entryp; 682 typedef png_sPLT_entry * * png_sPLT_entrypp; 683 684 /* When the depth of the sPLT palette is 8 bits, the color and alpha samples 685 * occupy the LSB of their respective members, and the MSB of each member 686 * is zero-filled. The frequency member always occupies the full 16 bits. 687 */ 688 689 typedef struct png_sPLT_struct 690 { 691 png_charp name; /* palette name */ 692 png_byte depth; /* depth of palette samples */ 693 png_sPLT_entryp entries; /* palette entries */ 694 png_int_32 nentries; /* number of palette entries */ 695 } png_sPLT_t; 696 typedef png_sPLT_t * png_sPLT_tp; 697 typedef const png_sPLT_t * png_const_sPLT_tp; 698 typedef png_sPLT_t * * png_sPLT_tpp; 699 700 #ifdef PNG_TEXT_SUPPORTED 701 /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file, 702 * and whether that contents is compressed or not. The "key" field 703 * points to a regular zero-terminated C string. The "text" fields can be a 704 * regular C string, an empty string, or a NULL pointer. 705 * However, the structure returned by png_get_text() will always contain 706 * the "text" field as a regular zero-terminated C string (possibly 707 * empty), never a NULL pointer, so it can be safely used in printf() and 708 * other string-handling functions. Note that the "itxt_length", "lang", and 709 * "lang_key" members of the structure only exist when the library is built 710 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by 711 * default without iTXt support. Also note that when iTXt *is* supported, 712 * the "lang" and "lang_key" fields contain NULL pointers when the 713 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or 714 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the 715 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag" 716 * which is always 0 or 1, or its "compression method" which is always 0. 717 * 718 * The location field (added in libpng 1.7.0) records where the text chunk was 719 * found when png_get_text is used. When png_set_text is used the field in the 720 * structure passed in is ignored and, instead, the field is set to the current 721 * write position. 722 * 723 * Prior to 1.7.0 the write behavior was the same; the text fields were written 724 * (once) at the next write_info call, however the read mechanism did not record 725 * the chunk location so if an info_struct from read was passed to the write 726 * APIs the text chunks would all be written at the start (before PLTE). 727 */ 728 typedef struct png_text_struct 729 { 730 int compression; /* compression value: 731 -1: tEXt, none 732 0: zTXt, deflate 733 1: iTXt, none 734 2: iTXt, deflate */ 735 png_byte location; /* 1: PNG_HAVE_IHDR 736 2: PNG_HAVE_PLTE 737 8: PNG_AFTER_IDAT */ 738 png_charp key; /* keyword, 1-79 character description of "text" */ 739 png_charp text; /* comment, may be an empty string (ie "") 740 or a NULL pointer */ 741 size_t text_length; /* length of the text string */ 742 size_t itxt_length; /* length of the itxt string */ 743 png_charp lang; /* language code, 0-79 characters 744 or a NULL pointer */ 745 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more 746 chars or a NULL pointer */ 747 } png_text; 748 typedef png_text * png_textp; 749 typedef const png_text * png_const_textp; 750 typedef png_text * * png_textpp; 751 #endif 752 753 /* Supported compression types for text in PNG files (tEXt, and zTXt). 754 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */ 755 #ifdef PNG_OLD_COMPRESSION_CODES_SUPPORTED 756 /* These values were used to prevent double write of text chunks in versions 757 * prior to 1.7.0. They are never set now; if you need them #define the 758 * _SUPPORTED macro. 759 */ 760 #define PNG_TEXT_COMPRESSION_NONE_WR -3 761 #define PNG_TEXT_COMPRESSION_zTXt_WR -2 762 #endif /* OLD_COMPRESSION_CODES */ 763 #define PNG_TEXT_COMPRESSION_NONE -1 764 #define PNG_TEXT_COMPRESSION_zTXt 0 765 #define PNG_ITXT_COMPRESSION_NONE 1 766 #define PNG_ITXT_COMPRESSION_zTXt 2 767 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */ 768 769 /* png_time is a way to hold the time in an machine independent way. 770 * Two conversions are provided, both from time_t and struct tm. There 771 * is no portable way to convert to either of these structures, as far 772 * as I know. If you know of a portable way, send it to me. As a side 773 * note - PNG has always been Year 2000 compliant! 774 */ 775 typedef struct png_time_struct 776 { 777 png_uint_16 year; /* full year, as in, 1995 */ 778 png_byte month; /* month of year, 1 - 12 */ 779 png_byte day; /* day of month, 1 - 31 */ 780 png_byte hour; /* hour of day, 0 - 23 */ 781 png_byte minute; /* minute of hour, 0 - 59 */ 782 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */ 783 } png_time; 784 typedef png_time * png_timep; 785 typedef const png_time * png_const_timep; 786 typedef png_time * * png_timepp; 787 788 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\ 789 defined(PNG_USER_CHUNKS_SUPPORTED) 790 /* png_unknown_chunk is a structure to hold queued chunks for which there is 791 * no specific support. The idea is that we can use this to queue 792 * up private chunks for output even though the library doesn't actually 793 * know about their semantics. 794 * 795 * The data in the structure is set by libpng on read and used on write. 796 */ 797 typedef struct png_unknown_chunk_t 798 { 799 png_byte *data; /* Data, should not be modified on read! */ 800 png_uint_32 size; /* Size of data, must not exceed 0x7fffffff. 801 * API CHANGE 1.7.0: changed from 'size_t' 802 */ 803 png_byte name[5]; /* Textual chunk name with '\0' terminator */ 804 805 /* On write 'location' must be set using the flag values listed below. 806 * Notice that on read it is set by libpng however the values stored have 807 * more bits set than are listed below. Always treat the value as a 808 * bitmask. On write set only one bit - setting multiple bits may cause the 809 * chunk to be written in multiple places. 810 */ 811 png_byte location; /* mode of operation at read time */ 812 } 813 png_unknown_chunk; 814 815 typedef png_unknown_chunk * png_unknown_chunkp; 816 typedef const png_unknown_chunk * png_const_unknown_chunkp; 817 typedef png_unknown_chunk * * png_unknown_chunkpp; 818 #endif 819 820 /* Flag values for the chunk location byte. */ 821 #define PNG_HAVE_IHDR 0x01U 822 #define PNG_HAVE_PLTE 0x02U 823 #define PNG_AFTER_IDAT 0x08U 824 825 /* Maximum positive integer used in PNG is (2^31)-1 */ 826 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL) 827 #define PNG_UINT_32_MAX ((png_uint_32)(-1)) 828 #define PNG_SIZE_MAX ((size_t)(-1)) 829 830 /* These are constants for fixed point values encoded in the 831 * PNG specification manner (x100000) 832 */ 833 #define PNG_FP_1 100000 834 #define PNG_FP_HALF 50000 835 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL) 836 #define PNG_FP_MIN (-PNG_FP_MAX) 837 838 /* These describe the color_type field in png_info. */ 839 /* color type masks */ 840 #define PNG_COLOR_MASK_PALETTE 1U 841 #define PNG_COLOR_MASK_COLOR 2U 842 #define PNG_COLOR_MASK_ALPHA 4U 843 844 /* color types. Note that not all combinations are legal */ 845 #define PNG_COLOR_TYPE_GRAY 0U 846 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE) 847 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR) 848 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA) 849 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA) 850 /* aliases */ 851 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA 852 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA 853 854 /* This is for compression type. PNG 1.0-1.2 only define the single type. */ 855 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */ 856 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE 857 858 /* This is for filter method. PNG 1.0-1.2 only defines a single method. 859 * 860 * NOTE: CONFUSING NAME. The specification refers to a 'method', one of the 861 * defines below, and a 'type', one of the FILTER_VALUE defines. 862 * Historically libpng uses TYPE for 'method' and VALUE for 'type'. 863 */ 864 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */ 865 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */ 866 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE 867 868 /* Filter values defined for method '0' (PNG_FILTER_TYPE_BASE) in the PNG 869 * specification. 870 */ 871 #define PNG_FILTER_VALUE_NONE 0 872 #define PNG_FILTER_VALUE_SUB 1 873 #define PNG_FILTER_VALUE_UP 2 874 #define PNG_FILTER_VALUE_AVG 3 875 #define PNG_FILTER_VALUE_PAETH 4 876 #define PNG_FILTER_VALUE_LAST 5 /* Not a valid value */ 877 878 /* These are for the interlacing type. These values should NOT be changed. */ 879 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */ 880 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */ 881 #define PNG_INTERLACE_LAST 2 /* Not a valid value */ 882 883 /* These are for the oFFs chunk. These values should NOT be changed. */ 884 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */ 885 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */ 886 #define PNG_OFFSET_LAST 2 /* Not a valid value */ 887 888 /* These are for the pCAL chunk. These values should NOT be changed. */ 889 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */ 890 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */ 891 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */ 892 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */ 893 #define PNG_EQUATION_LAST 4 /* Not a valid value */ 894 895 /* These are for the sCAL chunk. These values should NOT be changed. */ 896 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */ 897 #define PNG_SCALE_METER 1 /* meters per pixel */ 898 #define PNG_SCALE_RADIAN 2 /* radians per pixel */ 899 #define PNG_SCALE_LAST 3 /* Not a valid value */ 900 901 /* These are for the pHYs chunk. These values should NOT be changed. */ 902 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */ 903 #define PNG_RESOLUTION_METER 1 /* pixels/meter */ 904 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */ 905 906 /* These are for the sRGB chunk. These values should NOT be changed. */ 907 #define PNG_sRGB_INTENT_PERCEPTUAL 0 908 #define PNG_sRGB_INTENT_RELATIVE 1 909 #define PNG_sRGB_INTENT_SATURATION 2 910 #define PNG_sRGB_INTENT_ABSOLUTE 3 911 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */ 912 913 /* This is for text chunks */ 914 #define PNG_KEYWORD_MAX_LENGTH 79 915 916 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */ 917 #define PNG_MAX_PALETTE_LENGTH 256 918 919 /* These determine if an ancillary chunk's data has been successfully read 920 * from the PNG header, or if the application has filled in the corresponding 921 * data in the info_struct to be written into the output file. The values 922 * of the PNG_INFO_<chunk> defines should NOT be changed. 923 */ 924 #define PNG_INFO_gAMA 0x0001U 925 #define PNG_INFO_sBIT 0x0002U 926 #define PNG_INFO_cHRM 0x0004U 927 #define PNG_INFO_PLTE 0x0008U 928 #define PNG_INFO_tRNS 0x0010U 929 #define PNG_INFO_bKGD 0x0020U 930 #define PNG_INFO_hIST 0x0040U 931 #define PNG_INFO_pHYs 0x0080U 932 #define PNG_INFO_oFFs 0x0100U 933 #define PNG_INFO_tIME 0x0200U 934 #define PNG_INFO_pCAL 0x0400U 935 #define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */ 936 #define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */ 937 #define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */ 938 #define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */ 939 #define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */ 940 941 /* This is used for the transformation routines, as some of them 942 * change these values for the row. It also should enable using 943 * the routines for other purposes. 944 */ 945 typedef struct png_row_info_struct 946 { 947 png_uint_32 width; /* width of row */ 948 size_t rowbytes; /* number of bytes in row */ 949 png_byte color_type; /* color type of row */ 950 png_byte bit_depth; /* bit depth of row */ 951 png_byte channels; /* number of channels (1, 2, 3, or 4) */ 952 png_byte pixel_depth; /* bits per pixel (depth * channels) */ 953 } png_row_info; 954 955 typedef png_row_info * png_row_infop; 956 typedef png_row_info * * png_row_infopp; 957 958 /* These are the function types for the I/O functions and for the functions 959 * that allow the user to override the default I/O functions with his or her 960 * own. The png_error_ptr type should match that of user-supplied warning 961 * and error functions, while the png_rw_ptr type should match that of the 962 * user read/write data functions. Note that the 'write' function must not 963 * modify the buffer it is passed. The 'read' function, on the other hand, is 964 * expected to return the read data in the buffer. 965 */ 966 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp)); 967 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t)); 968 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp)); 969 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32, 970 int)); 971 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32, 972 int)); 973 974 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED 975 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop)); 976 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop)); 977 978 /* WARNING: the API for this callback is poorly documented and produces 979 * unexpected results when dealing with interlaced images. For non-interlaced 980 * images the parameters are straightforward: 981 * 982 * next_row: a pointer to the transformed row read from the PNG input 983 * stream, it has png_get_image_width() pixels. 984 * row_y: the y ordinate of the image; 0..png_get_image_height()-1 985 * pass: 0 986 * 987 * For interlaced images if png_set_interlace_handling has been called (libpng 988 * does *not* call this itself) the parameters are the same except that the 989 * pass will be the pass in the range 0..6 (NOTE: one less than the PNG spec) 990 * and 'next_row' will be NULL if (and only if) the row does not contribute 991 * to the output in 'blocky' display mode. 992 * 993 * pass: 0..6 994 * 995 * If 'next_row' is not NULL it is necessary for the application to combine the 996 * pixels with the output. This can most easily be done by calling 997 * png_progressive_combine_row(). Note that the 'next_row' data cannot be 998 * changed; even though the value is passed to png_progressive_combine_row the 999 * pointer is not used, it is just a flag , if it is NULL nothing will happen. 1000 * 1001 * If png_set_interlace_handling has not been called the callback only gets 1002 * called for original PNG interlaced row: 1003 * 1004 * row_y: the y ordinate in the pass; 0..PNG_PASS_ROWS()-1 1005 * 1006 * What is more if PNG_PASS_COLS() is 0 the entire pass will be skipped. The 1007 * row data is not full width and there is no guarantee that the buffer passed 1008 * in 'next_row' is able to accomodate the full width of output pixels, however 1009 * 'next_row' will never be NULL. 1010 * 1011 * Use PNG_ROW_FROM_PASS_ROW(row_y, pass) and PNG_COL_FROM_PASS_COL(col, pass) 1012 * to find the output pixel (x,y) given an interlaced sub-image pixel 1013 * (row_y,col,pass). (See below for these macros.) 1014 * 1015 * Note that in this latter case if you want to do the 'blocky' display update 1016 * method you have to work out all the details yourself with regard to which 1017 * pixels to set for each row and whether to replicate it to the following 1018 * rows of the image. 1019 */ 1020 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, 1021 png_bytep next_row, png_uint_32 row_y, int pass)); 1022 #endif 1023 1024 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED 1025 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop, 1026 png_bytep)); 1027 #endif 1028 1029 #ifdef PNG_USER_CHUNKS_SUPPORTED 1030 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp, 1031 png_unknown_chunkp)); 1032 #endif 1033 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED 1034 /* not used anywhere */ 1035 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */ 1036 #endif 1037 1038 #ifdef PNG_SETJMP_SUPPORTED 1039 /* This must match the function definition in <setjmp.h>, and the application 1040 * must include this before png.h to obtain the definition of jmp_buf. The 1041 * function is required to be PNG_NORETURN, but this is not checked. If the 1042 * function does return the application will crash via an abort() or similar 1043 * system level call. 1044 * 1045 * If you get a warning here while building the library you may need to make 1046 * changes to ensure that pnglibconf.h records the calling convention used by 1047 * your compiler. This may be very difficult - try using a different compiler 1048 * to build the library! 1049 */ 1050 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef); 1051 #endif 1052 1053 /* Transform masks for the high-level interface */ 1054 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */ 1055 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */ 1056 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */ 1057 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */ 1058 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */ 1059 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */ 1060 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */ 1061 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */ 1062 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */ 1063 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */ 1064 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */ 1065 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */ 1066 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */ 1067 /* Added to libpng-1.2.34 */ 1068 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER 1069 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */ 1070 /* Added to libpng-1.4.0 */ 1071 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */ 1072 /* Added to libpng-1.5.4 */ 1073 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */ 1074 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */ 1075 1076 /* Flags for MNG supported features */ 1077 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01 1078 #define PNG_FLAG_MNG_FILTER_64 0x04 1079 #define PNG_ALL_MNG_FEATURES 0x05 1080 1081 /* NOTE: prior to 1.5 these functions had no 'API' style declaration, 1082 * this allowed the zlib default functions to be used on Windows 1083 * platforms. In 1.5 the zlib default malloc (which just calls malloc and 1084 * ignores the first argument) should be completely compatible with the 1085 * following. 1086 */ 1087 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp, 1088 png_alloc_size_t)); 1089 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp)); 1090 1091 /* Section 4: exported functions 1092 * Here are the function definitions most commonly used. This is not 1093 * the place to find out how to use libpng. See libpng-manual.txt for the 1094 * full explanation, see example.c for the summary. This just provides 1095 * a simple one line description of the use of each function. 1096 * 1097 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in 1098 * pngconf.h and in the *.dfn files in the scripts directory. 1099 * 1100 * PNG_EXPORT(ordinal, type, name, (args)); 1101 * 1102 * ordinal: ordinal that is used while building 1103 * *.def files. The ordinal value is only 1104 * relevant when preprocessing png.h with 1105 * the *.dfn files for building symbol table 1106 * entries, and are removed by pngconf.h. 1107 * type: return type of the function 1108 * name: function name 1109 * args: function arguments, with types 1110 * 1111 * When we wish to append attributes to a function prototype we use 1112 * the PNG_EXPORTA() macro instead. 1113 * 1114 * PNG_EXPORTA(ordinal, type, name, (args), attributes); 1115 * 1116 * ordinal, type, name, and args: same as in PNG_EXPORT(). 1117 * attributes: function attributes 1118 */ 1119 1120 /* Returns the version number of the library */ 1121 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void)); 1122 1123 /* Tell lib we have already handled the first <num_bytes> magic bytes. 1124 * Handling more than 8 bytes from the beginning of the file is an error. 1125 */ 1126 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes)); 1127 1128 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a 1129 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG 1130 * signature, and non-zero otherwise. Having num_to_check == 0 or 1131 * start > 7 will always fail (ie return non-zero). 1132 */ 1133 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start, 1134 size_t num_to_check)); 1135 1136 /* Simple signature checking function. This is the same as calling 1137 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n). 1138 */ 1139 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n)) 1140 1141 /* Allocate and initialize png_ptr struct for reading, and any other memory. */ 1142 PNG_EXPORTA(4, png_structp, png_create_read_struct, 1143 (png_const_charp user_png_ver, png_voidp error_ptr, 1144 png_error_ptr error_fn, png_error_ptr warn_fn), 1145 PNG_ALLOCATED); 1146 1147 /* Allocate and initialize png_ptr struct for writing, and any other memory */ 1148 PNG_EXPORTA(5, png_structp, png_create_write_struct, 1149 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, 1150 png_error_ptr warn_fn), 1151 PNG_ALLOCATED); 1152 1153 /* These APIs control the size of the buffer used for reading IDAT chunks in the 1154 * sequential read code and the size of the IDAT chunks produced when writing. 1155 * They have no effect on the progressive read code. In both read and write 1156 * cases it will be necessary to allocate at least this amount of buffer space. 1157 * The default value is PNG_IDAT_READ_SIZE on read and PNG_ZBUF_SIZE on write. 1158 * 1159 * The valid range is 1..0x7FFFFFFF on write and 1..max(uInt) on read, where 1160 * uInt is the type declared by zlib.h. On write setting the largest value will 1161 * typically cause the PNG image data to be written in one chunk; this gives the 1162 * smallest PNG and has little or no effect on applications that read the PNG. 1163 * 1164 * DEPRECATED: use png_set_IDAT_size on write and png_set_read_buffer_size on 1165 * read. 1166 */ 1167 PNG_EXPORTA(6, png_alloc_size_t, png_get_compression_buffer_size, 1168 (png_const_structrp png_ptr), PNG_DEPRECATED); 1169 PNG_EXPORTA(7, void, png_set_compression_buffer_size, (png_structrp png_ptr, 1170 png_alloc_size_t size), PNG_DEPRECATED); 1171 #define png_set_read_buffer_size(p,size) (png_setting((p),\ 1172 PNG_SR_COMPRESS_buffer_size, (size), 0)) 1173 /* The size of the buffer used while processing compressed data, both single 1174 * chunk data (zTXt, iTXt, iCCP) and IDAT data. With IDAT data in libpng 1.7 1175 * IDATs are read until the end or until the buffer is full; this means that 1176 * you can optimize the buffer size for the particular memory behavior of 1177 * your system and, possibly, your application. 1178 * 1179 * NOTE: the result (on success) is 0, which is actually an invalid value. 1180 * Retrieving the current value is not possible. 1181 */ 1182 1183 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp 1184 * match up. 1185 */ 1186 #ifdef PNG_SETJMP_SUPPORTED 1187 /* This function returns the jmp_buf built in to *png_ptr. It must be 1188 * supplied with an appropriate 'longjmp' function to use on that jmp_buf 1189 * unless the default error function is overridden in which case NULL is 1190 * acceptable. The size of the jmp_buf is checked against the actual size 1191 * allocated by the library - the call will return NULL on a mismatch 1192 * indicating an ABI mismatch. 1193 */ 1194 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr, 1195 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size)); 1196 # define png_jmpbuf(png_ptr) \ 1197 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf)))) 1198 #else 1199 # define png_jmpbuf(png_ptr) \ 1200 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP) 1201 #endif 1202 /* This function should be used by libpng applications in place of 1203 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it 1204 * will use it; otherwise it will call PNG_ABORT(). This function was 1205 * added in libpng-1.5.0. 1206 */ 1207 PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val), 1208 PNG_NORETURN); 1209 1210 #ifdef PNG_READ_SUPPORTED 1211 /* Reset the compression stream -- Removed from libpng-1.7.0 */ 1212 PNG_REMOVED(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED) 1213 #endif 1214 1215 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */ 1216 #ifdef PNG_USER_MEM_SUPPORTED 1217 PNG_EXPORTA(11, png_structp, png_create_read_struct_2, 1218 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, 1219 png_error_ptr warn_fn, 1220 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn), 1221 PNG_ALLOCATED); 1222 PNG_EXPORTA(12, png_structp, png_create_write_struct_2, 1223 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, 1224 png_error_ptr warn_fn, 1225 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn), 1226 PNG_ALLOCATED); 1227 #endif 1228 1229 /* Write the PNG file signature. */ 1230 PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr)); 1231 1232 /* Write a PNG chunk - size, type, (optional) data, CRC. */ 1233 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, 1234 png_const_bytep chunk_name, png_const_voidp data, size_t length)); 1235 1236 /* Write the start of a PNG chunk - length and chunk name. */ 1237 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr, 1238 png_const_bytep chunk_name, png_uint_32 length)); 1239 1240 /* Write the data of a PNG chunk started with png_write_chunk_start(). */ 1241 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr, 1242 png_const_voidp data, size_t length)); 1243 1244 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */ 1245 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr)); 1246 1247 /* Allocate and initialize the info structure */ 1248 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr), 1249 PNG_ALLOCATED); 1250 1251 /* Removed from libpng-1.7.0 */ 1252 PNG_REMOVED(19, void, png_info_init_3, (png_infopp info_ptr, 1253 size_t png_info_struct_size), PNG_DEPRECATED) 1254 1255 /* Writes all the PNG information before the image. */ 1256 PNG_EXPORT(20, void, png_write_info_before_PLTE, 1257 (png_structrp png_ptr, png_const_inforp info_ptr)); 1258 PNG_EXPORT(21, void, png_write_info, 1259 (png_structrp png_ptr, png_const_inforp info_ptr)); 1260 1261 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1262 /* Read the information before the actual image data. */ 1263 PNG_EXPORT(22, void, png_read_info, 1264 (png_structrp png_ptr, png_inforp info_ptr)); 1265 #endif 1266 1267 #ifdef PNG_TIME_RFC1123_SUPPORTED 1268 /* Convert to a US string format: there is no localization support in this 1269 * routine. The original implementation used a 29 character buffer in 1270 * png_struct, this has been removed (in libpng 1.7.0). 1271 */ 1272 PNG_REMOVED(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr, 1273 png_const_timep ptime),PNG_DEPRECATED) 1274 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29], 1275 png_const_timep ptime)); 1276 #endif 1277 1278 #ifdef PNG_CONVERT_tIME_SUPPORTED 1279 /* Convert from a struct tm to png_time */ 1280 PNG_EXPORT(24, PNG_DEPRECATED void, png_convert_from_struct_tm, 1281 (png_timep ptime, const struct tm * ttime)); 1282 1283 /* Convert from time_t to png_time. Uses gmtime() */ 1284 PNG_EXPORT(25, PNG_DEPRECATED void, png_convert_from_time_t, (png_timep ptime, 1285 time_t ttime)); 1286 #endif /* CONVERT_tIME */ 1287 1288 #ifdef PNG_READ_EXPAND_SUPPORTED 1289 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */ 1290 PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr)); 1291 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr)); 1292 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr)); 1293 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr)); 1294 #endif 1295 1296 #ifdef PNG_READ_EXPAND_16_SUPPORTED 1297 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion 1298 * of a tRNS chunk if present. 1299 */ 1300 PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr)); 1301 #endif 1302 1303 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) 1304 /* Use blue, green, red order for pixels. */ 1305 PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr)); 1306 #endif 1307 1308 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 1309 /* Expand the grayscale to 24-bit RGB if necessary. */ 1310 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr)); 1311 #endif 1312 1313 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED 1314 /* Reduce RGB to grayscale. */ 1315 #define PNG_ERROR_ACTION_NO_CHECK 0 1316 #define PNG_ERROR_ACTION_NONE 1 1317 #define PNG_ERROR_ACTION_WARN 2 1318 #define PNG_ERROR_ACTION_ERROR 3 1319 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/ 1320 1321 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr, 1322 int error_action, double red, double green)) 1323 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr, 1324 int error_action, png_fixed_point red, png_fixed_point green)) 1325 /* Convert RGB pixels to gray (CIE Y) values, the red and green value must be 1326 * less than or equal to 1, if either is negative a set of defaults 1327 * corresponding to the sRGB standard are used. 1328 * 1329 * The error action specifies whether to check for r==g==b in each pixel, if 1330 * it is 0 (PNG_ERROR_ACTION_NO_CHECK; added in libpng 1.7.0) no check will 1331 * be performed, otherwise a check is performed and the result can be 1332 * retrieved using png_get_rgb_to_gray_status (which just returns a 1333 * true if a non-gray pixel was encountered). 1334 * 1335 * Pass PNG_ERROR_ACTION_ERROR if you are confident that the image only 1336 * contains gray pixels (you have already checked); the check is still 1337 * performed but a very optimized code path is used for RGB to gray 1338 * convertion. 1339 * 1340 * If you want to extract a single channel pass PNG_FP_1 for the coefficient 1341 * for that channel and 0 for the rest (0 for both red and green to extract 1342 * blue). 1343 * 1344 * NOTE: the default coefficients used if negative values are passed for red 1345 * or green are based on the cHRM chunk if available, otherwise sRGB. The 1346 * calculation returns the Y (luminance value) corresponding to the white 1347 * point of the PNG. UNLESS THE WHITE POINT IS D50 THIS IS NOT A CIEXYZ Y 1348 * VALUE. It is the luminance of the pixel perceived by a viewer completely 1349 * adapted to the white point of the PNG, this may not be what you want 1350 * because to interpret it you have to also record the white point of the 1351 * PNG. To obtain CIEXYZ Y values read the cHRM chunk XYZ values and 1352 * chromatically adapt them to D50 1353 */ 1354 1355 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp 1356 png_ptr)); 1357 #endif 1358 1359 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED 1360 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth, 1361 png_colorp palette)); 1362 #endif 1363 1364 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED 1365 /* How the alpha channel is interpreted - this affects how the color channels 1366 * of a PNG file are returned to the calling application when an alpha channel, 1367 * or a tRNS chunk in a palette file, is present. 1368 * 1369 * This has no effect on the way pixels are written into a PNG output 1370 * datastream. The color samples in a PNG datastream are never premultiplied 1371 * with the alpha samples. 1372 * 1373 * The default is to return data according to the PNG specification: the alpha 1374 * channel is a linear measure of the contribution of the pixel to the 1375 * corresponding composited pixel, and the color channels are unassociated 1376 * (not premultiplied). The gamma encoded color channels must be scaled 1377 * according to the contribution and to do this it is necessary to undo 1378 * the encoding, scale the color values, perform the composition and reencode 1379 * the values. This is the 'PNG' mode. 1380 * 1381 * The alternative is to 'associate' the alpha with the color information by 1382 * storing color channel values that have been scaled by the alpha. 1383 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes 1384 * (the latter being the two common names for associated alpha color channels). 1385 * 1386 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha 1387 * value is equal to the maximum value. 1388 * 1389 * The final choice is to gamma encode the alpha channel as well. This is 1390 * broken because, in practice, no implementation that uses this choice 1391 * correctly undoes the encoding before handling alpha composition. Use this 1392 * choice only if other serious errors in the software or hardware you use 1393 * mandate it; the typical serious error is for dark halos to appear around 1394 * opaque areas of the composited PNG image because of arithmetic overflow. 1395 * 1396 * The API function png_set_alpha_mode specifies which of these choices to use 1397 * with an enumerated 'mode' value and the gamma of the required output: 1398 */ 1399 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */ 1400 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */ 1401 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */ 1402 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */ 1403 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */ 1404 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */ 1405 1406 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode, 1407 double output_gamma)) 1408 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr, 1409 int mode, png_fixed_point output_gamma)) 1410 #endif 1411 1412 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED) 1413 /* The output_gamma value is a screen gamma in libpng terminology: it expresses 1414 * how to decode the output values, not how they are encoded. 1415 */ 1416 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */ 1417 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */ 1418 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */ 1419 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */ 1420 #endif 1421 1422 /* The following are examples of calls to png_set_alpha_mode to achieve the 1423 * required overall gamma correction and, where necessary, alpha 1424 * premultiplication. 1425 * 1426 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); 1427 * This is the default libpng handling of the alpha channel - it is not 1428 * pre-multiplied into the color components. In addition the call states 1429 * that the output is for a sRGB system and causes all PNG files without gAMA 1430 * chunks to be assumed to be encoded using sRGB. 1431 * 1432 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); 1433 * In this case the output is assumed to be something like an sRGB conformant 1434 * display preceeded by a power-law lookup table of power 1.45. This is how 1435 * early Mac systems behaved. 1436 * 1437 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR); 1438 * This is the classic Jim Blinn approach and will work in academic 1439 * environments where everything is done by the book. It has the shortcoming 1440 * of assuming that input PNG data with no gamma information is linear - this 1441 * is unlikely to be correct unless the PNG files where generated locally. 1442 * Most of the time the output precision will be so low as to show 1443 * significant banding in dark areas of the image. 1444 * 1445 * png_set_expand_16(pp); 1446 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB); 1447 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files 1448 * are assumed to have the sRGB encoding if not marked with a gamma value and 1449 * the output is always 16 bits per component. This permits accurate scaling 1450 * and processing of the data. If you know that your input PNG files were 1451 * generated locally you might need to replace PNG_DEFAULT_sRGB with the 1452 * correct value for your system. 1453 * 1454 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB); 1455 * If you just need to composite the PNG image onto an existing background 1456 * and if you control the code that does this you can use the optimization 1457 * setting. In this case you just copy completely opaque pixels to the 1458 * output. For pixels that are not completely transparent (you just skip 1459 * those) you do the composition math using png_composite or png_composite_16 1460 * below then encode the resultant 8-bit or 16-bit values to match the output 1461 * encoding. 1462 * 1463 * Other cases 1464 * If neither the PNG nor the standard linear encoding work for you because 1465 * of the software or hardware you use then you have a big problem. The PNG 1466 * case will probably result in halos around the image. The linear encoding 1467 * will probably result in a washed out, too bright, image (it's actually too 1468 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably 1469 * substantially reduce the halos. Alternatively try: 1470 * 1471 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB); 1472 * This option will also reduce the halos, but there will be slight dark 1473 * halos round the opaque parts of the image where the background is light. 1474 * In the OPTIMIZED mode the halos will be light halos where the background 1475 * is dark. Take your pick - the halos are unavoidable unless you can get 1476 * your hardware/software fixed! (The OPTIMIZED approach is slightly 1477 * faster.) 1478 * 1479 * When the default gamma of PNG files doesn't match the output gamma. 1480 * If you have PNG files with no gamma information png_set_alpha_mode allows 1481 * you to provide a default gamma, but it also sets the ouput gamma to the 1482 * matching value. If you know your PNG files have a gamma that doesn't 1483 * match the output you can take advantage of the fact that 1484 * png_set_alpha_mode always sets the output gamma but only sets the PNG 1485 * default if it is not already set: 1486 * 1487 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); 1488 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); 1489 * The first call sets both the default and the output gamma values, the 1490 * second call overrides the output gamma without changing the default. This 1491 * is easier than achieving the same effect with png_set_gamma. You must use 1492 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will 1493 * fire if more than one call to png_set_alpha_mode and png_set_background is 1494 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG 1495 * are ignored. 1496 */ 1497 1498 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED 1499 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr)); 1500 #endif 1501 1502 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ 1503 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) 1504 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr)); 1505 #endif 1506 1507 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ 1508 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) 1509 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr)); 1510 #endif 1511 1512 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) 1513 /* Add a filler byte to 8-bit Gray or 24-bit RGB images. */ 1514 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler, 1515 int flags)); 1516 /* The values of the PNG_FILLER_ defines should NOT be changed */ 1517 # define PNG_FILLER_BEFORE 0 1518 # define PNG_FILLER_AFTER 1 1519 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */ 1520 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr, 1521 png_uint_32 filler, int flags)); 1522 #endif /* READ_FILLER || WRITE_FILLER */ 1523 1524 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) 1525 /* Swap bytes in 16-bit depth files. */ 1526 PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr)); 1527 #endif 1528 1529 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) 1530 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */ 1531 PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr)); 1532 #endif 1533 1534 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \ 1535 defined(PNG_WRITE_PACKSWAP_SUPPORTED) 1536 /* Swap packing order of pixels in bytes. */ 1537 PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr)); 1538 #endif 1539 1540 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) 1541 /* Converts files to legal bit depths. */ 1542 PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p 1543 true_bits)); 1544 #endif 1545 1546 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \ 1547 defined(PNG_WRITE_INTERLACING_SUPPORTED) 1548 /* Have the code handle the interlacing. Returns the number of passes. 1549 * MUST be called before png_read_update_info or png_start_read_image, 1550 * otherwise it will not have the desired effect. Note that it is still 1551 * necessary to call png_read_row or png_read_rows png_get_image_height 1552 * times for each pass. 1553 */ 1554 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr)); 1555 #endif 1556 1557 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) 1558 /* Invert monochrome files */ 1559 PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr)); 1560 #endif 1561 1562 #ifdef PNG_READ_BACKGROUND_SUPPORTED 1563 /* Handle alpha and tRNS by replacing with a background color. Prior to 1564 * libpng-1.5.4 this API must not be called before the PNG file header has been 1565 * read. Doing so will result in unexpected behavior and possible warnings or 1566 * errors if the PNG file contains a bKGD chunk. 1567 */ 1568 PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr, 1569 png_const_color_16p background_color, int background_gamma_code, 1570 int need_expand, double background_gamma)) 1571 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr, 1572 png_const_color_16p background_color, int background_gamma_code, 1573 int need_expand, png_fixed_point background_gamma)) 1574 #endif 1575 #ifdef PNG_READ_BACKGROUND_SUPPORTED 1576 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0 1577 # define PNG_BACKGROUND_GAMMA_SCREEN 1 1578 # define PNG_BACKGROUND_GAMMA_FILE 2 1579 # define PNG_BACKGROUND_GAMMA_UNIQUE 3 1580 #endif 1581 1582 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED 1583 /* Scale a 16-bit depth file down to 8-bit, accurately. */ 1584 PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr)); 1585 #endif 1586 1587 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED 1588 #define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */ 1589 /* Strip the second byte of information from a 16-bit depth file. */ 1590 PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr)); 1591 #endif 1592 1593 #ifdef PNG_READ_QUANTIZE_SUPPORTED 1594 /* Turn on quantizing, and reduce the palette to the number of colors 1595 * available. 1596 */ 1597 PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr, 1598 png_colorp palette, int num_palette, int maximum_colors, 1599 png_const_uint_16p histogram, int full_quantize)); 1600 #endif 1601 1602 #ifdef PNG_READ_GAMMA_SUPPORTED 1603 /* The threshold on gamma processing is configurable but hard-wired into the 1604 * library. The following is the floating point variant. 1605 */ 1606 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001) 1607 1608 /* Handle gamma correction. Screen_gamma=(display_exponent). 1609 * NOTE: this API simply sets the screen and file gamma values. It will 1610 * therefore override the value for gamma in a PNG file if it is called after 1611 * the file header has been read - use with care - call before reading the PNG 1612 * file for best results! 1613 * 1614 * These routines accept the same gamma values as png_set_alpha_mode (described 1615 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either 1616 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value 1617 * is the inverse of a 'screen gamma' value. 1618 */ 1619 PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr, 1620 double screen_gamma, double override_file_gamma)) 1621 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr, 1622 png_fixed_point screen_gamma, png_fixed_point override_file_gamma)) 1623 #endif 1624 1625 #ifdef PNG_WRITE_FLUSH_SUPPORTED 1626 PNG_REMOVED(51, void, png_set_flush, (png_structrp png_ptr, int nrows), 1627 PNG_EMPTY) 1628 #define png_set_flush(p,v) (png_setting((p), PNG_SW_FLUSH, 0, (v))) 1629 /* Set how many lines between output flushes - 0 for no flushing. The result 1630 * on success is always 0. 1631 */ 1632 1633 /* Flush the current PNG output buffer */ 1634 PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr)); 1635 #endif /* WRITE_FLUSH */ 1636 1637 /* Optional update palette with requested transformations */ 1638 PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr)); 1639 1640 /* Optional call to update the users info structure */ 1641 PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr, 1642 png_inforp info_ptr)); 1643 1644 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1645 /* Read one or more rows of image data. */ 1646 PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row, 1647 png_bytepp display_row, png_uint_32 num_rows)); 1648 #endif 1649 1650 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1651 /* Read a row of data. */ 1652 PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row, 1653 png_bytep display_row)); 1654 #endif 1655 1656 #ifdef PNG_READ_IMAGE_SUPPORTED 1657 /* Read the whole image into memory at once. */ 1658 PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image)); 1659 #endif 1660 1661 /* Write a row of image data */ 1662 PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr, 1663 png_const_bytep row)); 1664 1665 /* Write a few rows of image data: (*row) is not written; however, the type 1666 * is declared as writeable to maintain compatibility with previous versions 1667 * of libpng and to allow the 'display_row' array from read_rows to be passed 1668 * unchanged to write_rows. 1669 */ 1670 PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row, 1671 png_uint_32 num_rows)); 1672 1673 /* Write the image data */ 1674 PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image)); 1675 1676 /* Write the end of the PNG file. */ 1677 PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr, 1678 png_inforp info_ptr)); 1679 1680 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED 1681 /* Read the end of the PNG file. */ 1682 PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr)); 1683 #endif 1684 1685 /* Free any memory associated with the png_info_struct */ 1686 PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr, 1687 png_infopp info_ptr_ptr)); 1688 1689 /* Free any memory associated with the png_struct and the png_info_structs */ 1690 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr, 1691 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr)); 1692 1693 /* Free any memory associated with the png_struct and the png_info_structs */ 1694 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr, 1695 png_infopp info_ptr_ptr)); 1696 1697 /* Set the libpng method of handling chunk CRC errors on read */ 1698 PNG_REMOVED(66, void, png_set_crc_action, (png_structrp png_ptr, 1699 int crit_action, int ancil_action), PNG_EMPTY) 1700 #define png_set_crc_action(png_ptr, crit, ancil)\ 1701 (png_setting((png_ptr), PNG_SR_CRC_ACTION, (crit), (ancil))) 1702 1703 /* Values for png_set_crc_action() say how to handle CRC errors in 1704 * ancillary and critical chunks, and whether to use the data contained 1705 * therein. Note that it is impossible to "discard" data in a critical 1706 * chunk. For versions prior to 0.90, the action was always error/quit, 1707 * whereas in version 0.90 and later, the action for CRC errors in ancillary 1708 * chunks is warn/discard. These values should NOT be changed. 1709 * 1710 * value action:critical action:ancillary 1711 */ 1712 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */ 1713 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */ 1714 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */ 1715 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */ 1716 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */ 1717 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */ 1718 1719 /* Write image filtering and compression options. 1720 * 1721 * These settings just change the very low level encoding of a PNG. The changes 1722 * make no difference to the image or the meta-data stored in the PNG. The API 1723 * used to make these changes can be disabled in a very minimal configuration, 1724 * if it is your compiler will report undefined values when the APIs below are 1725 * used. 1726 * 1727 * Write settings defined here, in order of ease of use: 1728 * 1729 * 1) Write compression settings: whether to optimize the write and the PNG 1730 * that results for read speed, final PNG size, write speed or memory 1731 * usage. 1732 * 2) IDAT size: What size to make the IDAT chunks in the PNG. 1733 * 3) PNG row filters to consider when writing the PNG. 1734 * 4) Very low level control over the deflate compression (useful mainly for 1735 * programs that want to try every option to find which gives the smallest 1736 * PNG.) 1737 */ 1738 #ifdef PNG_WRITE_SUPPORTED 1739 /* (1) Write compression settings: */ 1740 #define png_set_compression(p, v) (png_setting((p), PNG_SW_COMPRESS_png_level,\ 1741 0, (v))) 1742 /* Control the write compression of all chunks. This affects five basic 1743 * pieces of behavior: 1744 * 1745 * 1) The size of the PNG produced. 1746 * 2) The amount of memory the write code takes to produce the PNG. 1747 * 3) The amount of time the write code takes to produce the PNG. 1748 * 4) The amount of memory required to read the resultant PNG. 1749 * 5) The amount of time required to read the resultant PNG. 1750 * 1751 * There is considerable interdependence between these variables. As a 1752 * result there are a limited number of options: 1753 */ 1754 # define PNG_COMPRESSION_LOW_MEMORY (1) 1755 /* Minimize the memory required both when reading (4) and writing (2) the 1756 * PNG. This results in a significantly larger PNG (which may itself have 1757 * the opposite effect of slowing down either read or write) however the 1758 * memory overhead is reduced and, apart from the extra time to read the 1759 * data, the read time is likely to be reduced too. 1760 * 1761 * Use this when both read and write will happen on a memory starved 1762 * (really, very low memory) system. Note that this sets a high deflate 1763 * compression setting because that does not affect zlib memory usage. 1764 */ 1765 # define PNG_COMPRESSION_HIGH_SPEED (2) 1766 /* Minimize the time to both read (5) and write (3) the PNG. This uses 1767 * slightly more memory on read and potentially significantly more on 1768 * write but is optimized for maximum speed in both cases. 1769 * 1770 * Use this when both read and write need to be fast and PNG size is not 1771 * likely to be an issue. An example would be if you are using PNG to 1772 * pass intermediate data between applications on the same machine. 1773 */ 1774 # define PNG_COMPRESSION_HIGH_READ_SPEED (3) 1775 /* Minimize the time to read (5) the PNG. This also reduces the amount 1776 * of memory on read, however some options which require more memory but 1777 * are likely to decrease PNG size, therefore improve read spead, are 1778 * used. 1779 * 1780 * This is one of the 'normal' options; options that are used when a 1781 * reasonably capable write machine is producing PNG files that will be 1782 * read many times. In this case the option is optimizing for speed on 1783 * read even if it increases the size of the PNG. 1784 */ 1785 # define PNG_COMPRESSION_LOW (4) 1786 /* This switches on options which do affect speed of both compression and 1787 * decompression, but biases the choice towards higher performance in both 1788 * cases. (So it is something of a compromise between all-out speed and 1789 * PNG compression). 1790 * 1791 * This is a good default to use in typical usages where PNG file size is 1792 * less of an issue than the overheads on reading a PNG file. 1793 * 1794 * Use this option when producing PNG files that are not expected to be 1795 * distributed widely or where read speed is more important than size. 1796 * This is also a good default for small images where the slight increase 1797 * in size of the compressed data doesn't change the file size much. 1798 */ 1799 # define PNG_COMPRESSION_MEDIUM (5) 1800 /* This is a compromise which switches on the options found most helpful 1801 * across a wide range of files without switching on the full range of 1802 * options which would decrease file size only a little while taking a lot 1803 * more time. PNG read memory (4) or time (5) is not a factor in the 1804 * choice of options; only write time (3). 1805 * 1806 * This is closest to the default used in prior versions of libpng. There 1807 * seems no logic to using it if the actual requirements are known and, 1808 * even if they aren't, it is probably better to guess 'LOW' or 'HIGH'. 1809 * 1810 * This is the normal libpng default. 1811 */ 1812 # define PNG_COMPRESSION_HIGH (6) 1813 /* This turns on everything which reduces file size on aggregate across a 1814 * large test set of files. It optimizes solely for the size of the 1815 * resultant PNG (1). 1816 * 1817 * This is a good default to use if file size is all important; it was the 1818 * stated original default in the PNG design, but the implementation of 1819 * libpng never used it. 1820 * 1821 * Use this setting in image authoring applications when writing the 1822 * finished image in PNG format. 1823 * 1824 * NOTE: several PNG file size optimizers exist (see the web-site 1825 * libpng.org). libpng does not perform the same functions as these 1826 * optimizers; libpng does not search for the best compression settings. 1827 * For this reason if you really want to minimize the size of the PNG files 1828 * produced use PNG_COMPRESSION_HIGH_SPEED then post-process the result 1829 * with one of the many PNG optimization programs. 1830 */ 1831 # define PNG_COMPRESSION_COMPAT (0) 1832 /* DEPRECATED: this is provided as a setting to aid transition of test 1833 * suites between major library versions (1.5 or 1.6 moving to 1.7). The 1834 * default settings change in 1.7 so, while the PNG files produced do not 1835 * change, their encoding does. Test systems that rely on constant 1836 * encoding can use this to verify that this is all that has changed. 1837 * 1838 * NOTE: the option will be removed at some point. It is difficult to 1839 * maintain and adds to libpng code size. 1840 * 1841 * NOTE: there are other changes in major and minor releases, such as 1842 * better ancillary chunk error handling, that also cause binary changes 1843 * to the PNG files libpng generates. Furthermore versions of libpng 1844 * prior to 1.7 included random data from uninitialized memory in the 1845 * image data under certain circumstances; this meant that earlier 1846 * versions were often not even consistent across two writes of the same 1847 * PNG file! 1848 */ 1849 1850 /* png_set_compression sets the default for all libpng compression operations. 1851 * While the setting is the same for all chunks it results in different 1852 * compression options for different chunks. The setting can be applied 1853 * separately to each class of chunks as follows: 1854 */ 1855 #define png_set_image_compression(p, v) (png_setting((p),\ 1856 PNG_SW_COMPRESS_png_level, png_IDAT, (v))) 1857 /* Control the compression of the image data (IDAT) chunks. */ 1858 1859 #define png_set_ICC_profile_compression(p, v) (png_setting((p),\ 1860 PNG_SW_COMPRESS_png_level, png_iCCP, (v))) 1861 /* Control the compression of ICC profiles (iCCP chunks.) */ 1862 1863 #define png_set_text_compression(p, v) (png_setting((p),\ 1864 PNG_SW_COMPRESS_png_level, png_zTXt, (v))) 1865 /* Control the compression of text (png_zTXt and png_iTXt) chunks. */ 1866 1867 /* (2) IDAT size: */ 1868 #define png_set_IDAT_size(p, v) (png_setting((p), PNG_SW_IDAT_size, (v), 0)) 1869 /* Set the maximum size of the IDAT chunks libpng writes. Valid values are 1870 * in the range 1U..0x7fffffffU, the default is 'PNG_ZBUF_SIZE' (a 1871 * historically confusing name) and this default *also* controls the size of 1872 * the buffer the read code uses when reading IDAT chunks. 1873 * 1874 * libpng has to buffer the data in the IDAT chunk before it writes any of 1875 * it, therefore this number directly controls that part of the memory 1876 * overhead while writing a PNG. There is a 12 byte per chunk overhead, so 1877 * the number also directly affects the size of the PNG. The number has no 1878 * significant effect (beyond the latter size effect) on the read code. 1879 */ 1880 #endif /* WRITE */ 1881 1882 /* These functions give the user control over the scan-line filtering in 1883 * libpng and the compression methods used by zlib. These functions are 1884 * mainly useful for testing, as the defaults should work with most users. 1885 * Those users who are tight on memory or want faster performance at the 1886 * expense of compression can modify them. See the compression library 1887 * header file (zlib.h) for an explination of the compression functions. 1888 */ 1889 1890 #ifdef PNG_WRITE_FILTER_SUPPORTED 1891 /* (3) PNG row filters to consider when writing the PNG. 1892 * 1893 * Control the filtering method(s) used by libpng for the write of subsequent 1894 * rows of the image. The argument is either a single filter value (one of the 1895 * PNG_FILTER_VALUE_ defines above), in which case that filter will be used on 1896 * following rows, or a mask of filter values (logical or of the PNG_FILTER_ 1897 * bit masks that follow PNG_FILTER_VALUE_*). Support for selection of a filter 1898 * from a mask with more than one bit set is dependent on 1899 * PNG_SELECT_FILTER_SUPPORTED, however support is the default configuration of 1900 * libpng. If support is not available the lowest bit set in the mask (the 1901 * lowest numbered filter) is used. 1902 * 1903 * The set of filters may be changed at any time, the new values will affect the 1904 * next row written. 1905 * 1906 * The 'method' must match that passed to png_set_IHDR; it cannot be changed and 1907 * is ignored in 1.7 and later. 1908 * 1909 * If multiple filters are enabled libpng will select one according to the 1910 * following rules: 1911 * 1912 * 1) On the first row of a pass UP is ignored if NONE is set and PAETH is 1913 * ignored if SUB is set; this is because these filter pairs are equivalent 1914 * when there is no previous row. 1915 * 1916 * 2) PNG_SELECT_FILTER_SUPPORTED: 1917 * If the PNG rows are long enough (have enough bytes) libpng will process a 1918 * row at a time; it will buffer the row if necessary. It uses a heuristic 1919 * based on the closeness of the filtered values to 0 to determine which 1920 * filter to use. 1921 * 1922 * 3) !PNG_SELECT_FILTER_SUPPORTED: 1923 * libpng selects the first filter in the list (there is no warning that this 1924 * will happen - check the #defines if you need to know.) 1925 * 1926 * The 'up', 'avg' and 'Paeth' filters require the previous image row to work. 1927 * If it is not available they are removed from the set of filters to try. The 1928 * first time the filter mask includes one of these filters libpng turns on 1929 * saving of the row. The filters do work on the first row of a pass, where 1930 * there is no previous row from the image. The PNG standard defines the 1931 * previous row as consisting of all 0 bytes in this case. That definition 1932 * causes the filters to have the following properties on the first row of a 1933 * pass: 1934 * 1935 * UP: The same as NONE (i.e. no filtering). 1936 * AVG: Uses the arithmetic (not modular arithmetc!) half of the preceding 1937 * pixel as the predictor. This is unique and not typically very 1938 * useful. 1939 * PAETH: The same as SUB. 1940 * 1941 * As a result with all versions of libpng if you want to use any of these 1942 * filters anywhere in the image you need only turn on one of them on the first 1943 * row of the image, or of a pass for interlaced images. For example if you 1944 * want to use 'sub' on the first row simply set 'sub'+'Paeth' in the mask; 1945 * libpng will automatically eliminate the Paeth algorithm from consideration 1946 * because it knows that 'sub' will rank equal or (if the filter byte is taken 1947 * into account) better. 1948 * 1949 * This approach is portable to earlier versions of libpng, however it may be 1950 * difficult to program. 1.7 allows you to directly specify whether or not to 1951 * retain the previous row. This is simpler and allows you to turn off previous 1952 * row retention if you want to. 1953 */ 1954 PNG_REMOVED(67, void, png_set_filter, (png_structrp png_ptr, int method, 1955 int filters), PNG_EMPTY) 1956 1957 #define png_set_filter(p, m, f) (png_setting((p), PNG_SW_COMPRESS_filters,\ 1958 (m), (f))) 1959 /* 'm' is the method and must be 0 (PNG_FILTER_TYPE_BASE) unless MNG 1960 * processing is supported (very unusual). 'f' is either a single value, 1961 * PNG_FILTER_VALUE_* below, or a combination of one or more PNG_FILTER_MASK 1962 * values. 1963 * 1964 * This sets the filter mask (or value) for the *next* row that is written. 1965 * It may be called at any time but does not have any effect until the next 1966 * row starts to be written. 1967 * 1968 * The return value is the mask that is set (or, with PNG_SF_GET, the 1969 * currently set mask). When PNG_SELECT_FILTER_SUPPORTED is not defined this 1970 * mask will have only one bit. 1971 * 1972 * NOTE: with PNG_SF_GET the result will be PNG_UNSET if png_set_filter has 1973 * not been called before and row writing has not started. 1974 */ 1975 1976 #define png_set_row_buffers(p, onoff) (png_setting((p),\ 1977 PNG_SW_COMPRESS_row_buffers, (onoff), 0)) 1978 /* If you intend to change the filter list after the first row using the 1979 * previous API call png_set_row_buffers(png_ptr, 1) if you intend to use UP, 1980 * AVG or Paeth filters. 1981 * 1982 * You can turn the buffering on and off dynamically, just as with 1983 * png_set_filter. 1984 * 1985 * The second argument should be 0 (off) or 1 (on). In the future it may be 1986 * used to control the maximum number of rows buffered. 1987 */ 1988 #endif /* WRITE_FILTER */ 1989 1990 /* The PNG_FILTER_VALUE_ definitions (the filter values from the base PNG spec) 1991 * are valid arguments to png_set_filter() if only a single filter is to be 1992 * used. If multiple filters are to be allowed (the default is to allow any of 1993 * them) then a combination of the following masks must be used and the low 1994 * three bits of the argument to png_set_filter must be 0. 1995 * 1996 * The resultant argument fits in a single byte in either case. 1997 */ 1998 #define PNG_FILTER_MASK(value) (0x08 << (value)) 1999 #define PNG_FILTER_NONE PNG_FILTER_MASK(PNG_FILTER_VALUE_NONE) 2000 #define PNG_FILTER_SUB PNG_FILTER_MASK(PNG_FILTER_VALUE_SUB) 2001 #define PNG_FILTER_UP PNG_FILTER_MASK(PNG_FILTER_VALUE_UP) 2002 #define PNG_FILTER_AVG PNG_FILTER_MASK(PNG_FILTER_VALUE_AVG) 2003 #define PNG_FILTER_PAETH PNG_FILTER_MASK(PNG_FILTER_VALUE_PAETH) 2004 2005 /* Then three convenience values. PNG_NO_FILTERS is the same as 2006 * PNG_FILTER_VALUE_NONE, but this is harmless because they mean the same thing. 2007 */ 2008 #define PNG_NO_FILTERS 0x00 2009 #define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP) 2010 #define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH) 2011 2012 #ifdef PNG_WRITE_SUPPORTED 2013 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */ 2014 PNG_REMOVED(68, void, png_set_filter_heuristics, 2015 (png_structrp png_ptr, int heuristic_method, int num_weights, 2016 png_const_doublep filter_weights, png_const_doublep filter_costs), 2017 PNG_DEPRECATED) 2018 PNG_REMOVED(209, void, png_set_filter_heuristics_fixed, 2019 (png_structrp png_ptr, int heuristic_method, int num_weights, 2020 png_const_fixed_point_p filter_weights, 2021 png_const_fixed_point_p filter_costs), 2022 PNG_DEPRECATED) 2023 /* Neither of these API calls did anything in libpng 1.6, however they were 2024 * not marked PNG_DEPRECATED, so they are converted to no-op function-like 2025 * macros here. (NOTE: the macro arguments are evaluated once each, this 2026 * will probably cause warnings with some compiler options: simply remove the 2027 * function call after ensuring that the arguments had no side effects.) 2028 */ 2029 #define png_set_filter_heuristics(p,m,w,fw,fc) ((void)(p,m,w,fw,fc)) 2030 #define png_set_filter_heuristics_fixed(p,m,w,fw,fc) ((void)(p,m,w,fw,fc)) 2031 #endif /* WRITE_WEIGHTED_FILTER */ 2032 2033 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED 2034 PNG_REMOVED(69, void, png_set_compression_level, (png_structrp png_ptr, 2035 int level), PNG_EMPTY) 2036 #define png_set_compression_level(p, v) (png_setting((p),\ 2037 PNG_SW_COMPRESS_zlib_level, png_IDAT, (v))) 2038 2039 PNG_REMOVED(70, void, png_set_compression_mem_level, (png_structrp png_ptr, 2040 int mem_level), PNG_EMPTY) 2041 #define png_set_compression_mem_level(p, v) (png_setting((p),\ 2042 PNG_SW_COMPRESS_memLevel, png_IDAT, (v))) 2043 2044 PNG_REMOVED(71, void, png_set_compression_strategy, (png_structrp png_ptr, 2045 int strategy), PNG_EMPTY) 2046 #define png_set_compression_strategy(p, v) (png_setting((p),\ 2047 PNG_SW_COMPRESS_strategy, png_IDAT, (v))) 2048 2049 PNG_REMOVED(72, void, png_set_compression_window_bits, (png_structrp png_ptr, 2050 int window_bits), PNG_EMPTY) 2051 #define png_set_compression_window_bits(p, v) (png_setting((p),\ 2052 PNG_SW_COMPRESS_windowBits, png_IDAT, (v))) 2053 2054 PNG_REMOVED(73, void, png_set_compression_method, (png_structrp png_ptr, 2055 int method), PNG_EMPTY) 2056 #define png_set_compression_method(p, v) (png_setting((p),\ 2057 PNG_SW_COMPRESS_method, png_IDAT, (v))) 2058 #endif /* WRITE_CUSTOMIZE_COMPRESSION */ 2059 2060 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED 2061 /* Also set zlib parameters for compressing non-IDAT chunks */ 2062 PNG_REMOVED(222, void, png_set_text_compression_level, (png_structrp png_ptr, 2063 int level), PNG_EMPTY) 2064 #define png_set_text_compression_level(p, v) (png_setting((p),\ 2065 PNG_SW_COMPRESS_zlib_level, png_zTXt, (v))) 2066 2067 PNG_REMOVED(223, void, png_set_text_compression_mem_level, 2068 (png_structrp png_ptr, int mem_level), PNG_EMPTY) 2069 #define png_set_text_compression_mem_level(p, v) (png_setting((p),\ 2070 PNG_SW_COMPRESS_memLevel, png_zTXt, (v))) 2071 2072 PNG_REMOVED(224, void, png_set_text_compression_strategy, (png_structrp png_ptr, 2073 int strategy), PNG_EMPTY) 2074 #define png_set_text_compression_strategy(p, v) (png_setting((p),\ 2075 PNG_SW_COMPRESS_strategy, png_zTXt, (v))) 2076 2077 PNG_REMOVED(225, void, png_set_text_compression_window_bits, 2078 (png_structrp png_ptr, int window_bits), PNG_EMPTY) 2079 #define png_set_text_compression_window_bits(p, v) (png_setting((p),\ 2080 PNG_SW_COMPRESS_windowBits, png_zTXt, (v))) 2081 2082 PNG_REMOVED(226, void, png_set_text_compression_method, (png_structrp png_ptr, 2083 int method), PNG_EMPTY) 2084 #define png_set_text_compression_method(p, v) (png_setting((p),\ 2085 PNG_SW_COMPRESS_method, png_zTXt, (v))) 2086 2087 /* NOTE: in versions of libpng prior to 1.7 iCCP compression was controlled by 2088 * the text settings, hence the controls were only available if 2089 * PNG_WRITE_CUSTOMIZIZE_ZTXT_COMPRESSION_SUPPORTED. In 1.7 the text settings 2090 * no longer affect iCCP compression, the following macros must be used (if 2091 * necessary): 2092 */ 2093 #define png_set_ICC_profile_compression_level(p, v) (png_setting((p),\ 2094 PNG_SW_COMPRESS_zlib_level, png_iCCP, (v))) 2095 #define png_set_ICC_profile_compression_mem_level(p, v) (png_setting((p),\ 2096 PNG_SW_COMPRESS_memLevel, png_iCCP, (v))) 2097 #define png_set_ICC_profile_compression_strategy(p, v) (png_setting((p),\ 2098 PNG_SW_COMPRESS_strategy, png_iCCP, (v))) 2099 #define png_set_ICC_profile_compression_window_bits(p, v) (png_setting((p),\ 2100 PNG_SW_COMPRESS_windowBits, png_iCCP, (v))) 2101 #define png_set_ICC_profile_compression_method(p, v) (png_setting((p),\ 2102 PNG_SW_COMPRESS_method, png_iCCP, (v))) 2103 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ 2104 #endif /* WRITE */ 2105 2106 /* These next functions are called for input/output, memory, and error 2107 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c, 2108 * and call standard C I/O routines such as fread(), fwrite(), and 2109 * fprintf(). These functions can be made to use other I/O routines 2110 * at run time for those applications that need to handle I/O in a 2111 * different manner by calling png_set_???_fn(). See libpng-manual.txt for 2112 * more information. 2113 */ 2114 2115 #ifdef PNG_STDIO_SUPPORTED 2116 /* Initialize the input/output for the PNG file to the default functions. */ 2117 PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp)); 2118 #endif 2119 2120 /* Replace the (error and abort), and warning functions with user 2121 * supplied functions. If no messages are to be printed you must still 2122 * write and use replacement functions. The replacement error_fn should 2123 * still do a longjmp to the last setjmp location if you are using this 2124 * method of error handling. If error_fn or warning_fn is NULL, the 2125 * default function will be used. 2126 */ 2127 2128 PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr, 2129 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn)); 2130 2131 /* Return the user pointer associated with the error functions */ 2132 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr)); 2133 2134 /* Replace the default data output functions with a user supplied one(s). 2135 * If buffered output is not used, then output_flush_fn can be set to NULL. 2136 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time 2137 * output_flush_fn will be ignored (and thus can be NULL). 2138 * It is probably a mistake to use NULL for output_flush_fn if 2139 * write_data_fn is not also NULL unless you have built libpng with 2140 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's 2141 * default flush function, which uses the standard *FILE structure, will 2142 * be used. 2143 */ 2144 PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr, 2145 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)); 2146 2147 /* Replace the default data input function with a user supplied one. */ 2148 PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr, 2149 png_rw_ptr read_data_fn)); 2150 2151 /* Return the user pointer associated with the I/O functions */ 2152 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr)); 2153 2154 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr, 2155 png_read_status_ptr read_row_fn)); 2156 2157 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr, 2158 png_write_status_ptr write_row_fn)); 2159 2160 #ifdef PNG_USER_MEM_SUPPORTED 2161 /* Replace the default memory allocation functions with user supplied one(s). */ 2162 PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr, 2163 png_malloc_ptr malloc_fn, png_free_ptr free_fn)); 2164 /* Return the user pointer associated with the memory functions */ 2165 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr)); 2166 #endif 2167 2168 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED 2169 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr, 2170 png_user_transform_ptr read_user_transform_fn)); 2171 #endif 2172 2173 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED 2174 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr, 2175 png_user_transform_ptr write_user_transform_fn)); 2176 #endif 2177 2178 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED 2179 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr, 2180 png_voidp user_transform_ptr, int user_transform_depth, 2181 int user_transform_channels)); 2182 /* Return the user pointer associated with the user transform functions */ 2183 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr, 2184 (png_const_structrp png_ptr)); 2185 #endif 2186 2187 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED 2188 /* Return information about the row currently being processed. Note that these 2189 * APIs do not fail but will return unexpected results if called outside a user 2190 * transform callback. Also note that when transforming an interlaced image the 2191 * row number is the row number within the sub-image of the interlace pass, so 2192 * the value will increase to the height of the sub-image (not the full image) 2193 * then reset to 0 for the next pass. 2194 * 2195 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to 2196 * find the output pixel (x,y) given an interlaced sub-image pixel 2197 * (row,col,pass). (See below for these macros.) 2198 */ 2199 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp)); 2200 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp)); 2201 #endif 2202 2203 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED 2204 /* This callback is called only for *unknown* chunks. If 2205 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known 2206 * chunks to be treated as unknown, however in this case the callback must do 2207 * any processing required by the chunk and this is not possible for any chunk 2208 * that affects the image reading (e.g. PLTE, tRNS). 2209 * 2210 * There is no write support - on write, by default, all the chunks in the 2211 * 'unknown' list are written in the specified position. 2212 * 2213 * The integer return from the callback function is interpreted thus: 2214 * 2215 * negative: An error occurred; png_chunk_error will be called. 2216 * zero: The chunk was not handled, the default unknown handling is used 2217 * (even if this was a chunk that would otherwise be known.) 2218 * NOTE: prior to libpng 1.7 handling values of 2219 * PNG_HANDLE_CHUNK_AS_DEFAULT and PNG_HANDLE_CHUNK_NEVER were 2220 * converted to PNG_HANDLE_CHUNK_IF_SAFE (libpng 1.6.0 warns if this 2221 * happens) so it was not possible to discard unknown chunk data if a 2222 * user callback was installed. 2223 * positive: The chunk was handled, libpng will ignore/discard it. 2224 * 2225 * WARNING: if this callback is set every chunk in the stream is temporarily 2226 * read into a memory buffer. This has potential performance implications, 2227 * particularly for small PNG images with large amounts of ancilliary 2228 * information. 2229 */ 2230 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr, 2231 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn)); 2232 #endif 2233 2234 #ifdef PNG_USER_CHUNKS_SUPPORTED 2235 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr)); 2236 #endif 2237 2238 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED 2239 /* Sets the function callbacks for the push reader, and a pointer to a 2240 * user-defined structure available to the callback functions. 2241 */ 2242 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr, 2243 png_voidp progressive_ptr, png_progressive_info_ptr info_fn, 2244 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn)); 2245 2246 /* Returns the user pointer associated with the push read functions */ 2247 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr, 2248 (png_const_structrp png_ptr)); 2249 2250 /* Function to be called when data becomes available */ 2251 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr, 2252 png_inforp info_ptr, png_bytep buffer, size_t buffer_size)); 2253 2254 /* A function which may be called *only* within png_process_data to stop the 2255 * processing of any more data. The function returns the number of bytes 2256 * remaining, excluding any that libpng has cached internally. A subsequent 2257 * call to png_process_data must supply these bytes again. If the argument 2258 * 'save' is set to true the routine will first save all the pending data and 2259 * will always return 0. 2260 */ 2261 PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save)); 2262 2263 /* A function which may be called *only* outside (after) a call to 2264 * png_process_data. It returns the number of bytes of data to skip in the 2265 * input. Normally it will return 0, but if it returns a non-zero value the 2266 * application must skip than number of bytes of input data and pass the 2267 * following data to the next call to png_process_data. 2268 */ 2269 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp)); 2270 2271 #ifdef PNG_READ_INTERLACING_SUPPORTED 2272 /* Function that combines rows. 'new_row' is a flag that should come from 2273 * the callback and be non-NULL if anything needs to be done; the library 2274 * stores its own version of the new data internally and ignores the passed 2275 * in value. 2276 */ 2277 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr, 2278 png_bytep old_row, png_const_bytep new_row)); 2279 #endif /* READ_INTERLACING */ 2280 #endif /* PROGRESSIVE_READ */ 2281 2282 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr, 2283 png_alloc_size_t size), PNG_ALLOCATED); 2284 /* Added at libpng version 1.4.0 */ 2285 PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr, 2286 png_alloc_size_t size), PNG_ALLOCATED); 2287 2288 /* Added at libpng version 1.2.4 */ 2289 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr, 2290 png_alloc_size_t size), PNG_ALLOCATED); 2291 2292 /* Frees a pointer allocated by png_malloc() */ 2293 PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr)); 2294 2295 /* Free data that was allocated internally */ 2296 PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr, 2297 png_inforp info_ptr, png_uint_32 free_me, int num)); 2298 2299 /* Reassign responsibility for freeing existing data, whether allocated 2300 * by libpng or by the application; this works on the png_info structure passed 2301 * in, it does not change the state for other png_info structures. 2302 * 2303 * It is unlikely that this function works correctly as of 1.6.0 and using it 2304 * may result either in memory leaks or double free of allocated data. It was 2305 * removed in libpng 1.7.0. 2306 */ 2307 PNG_REMOVED(99, void, png_data_freer, (png_const_structrp png_ptr, 2308 png_inforp info_ptr, int freer, png_uint_32 mask), PNG_DEPRECATED) 2309 2310 /* Flags for png_free_data */ 2311 #define PNG_FREE_HIST 0x0008U 2312 #define PNG_FREE_ICCP 0x0010U 2313 #define PNG_FREE_SPLT 0x0020U 2314 #define PNG_FREE_ROWS 0x0040U 2315 #define PNG_FREE_PCAL 0x0080U 2316 #define PNG_FREE_SCAL 0x0100U 2317 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 2318 # define PNG_FREE_UNKN 0x0200U 2319 #endif 2320 /* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */ 2321 #define PNG_FREE_PLTE 0x1000U 2322 #define PNG_FREE_TRNS 0x2000U 2323 #define PNG_FREE_TEXT 0x4000U 2324 #define PNG_FREE_ALL 0x7fffU 2325 #define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */ 2326 2327 #ifdef PNG_USER_MEM_SUPPORTED 2328 /* These were deprecated in libpng 1.6.0 and have been removed from libpng 2329 * 1.7.0; the functionality should be accessed by calling malloc or free 2330 * directly or, if png_error handling is required, calling png_malloc. 2331 */ 2332 PNG_REMOVED(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr, 2333 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED) 2334 PNG_REMOVED(101, void, png_free_default, (png_const_structrp png_ptr, 2335 png_voidp ptr), PNG_DEPRECATED) 2336 #endif 2337 2338 #ifdef PNG_ERROR_TEXT_SUPPORTED 2339 /* Fatal error in PNG image of libpng - can't continue */ 2340 PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr, 2341 png_const_charp error_message), PNG_NORETURN); 2342 #else 2343 /* Fatal error in PNG image of libpng - can't continue */ 2344 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN); 2345 # define png_error(s1,s2) png_err(s1) 2346 #endif 2347 2348 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED) 2349 /* The same, but the chunk name is prepended to the error string. */ 2350 PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr, 2351 png_const_charp error_message), PNG_NORETURN); 2352 #else 2353 # define png_chunk_error(s1,s2) png_error(s1,s2) 2354 #endif 2355 2356 #ifdef PNG_WARNINGS_SUPPORTED 2357 /* Non-fatal error in libpng. Can continue, but may have a problem. */ 2358 PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr, 2359 png_const_charp warning_message)); 2360 2361 /* Non-fatal error in libpng, chunk name is prepended to message. */ 2362 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr, 2363 png_const_charp warning_message)); 2364 #else 2365 # define png_warning(s1,s2) ((void)(s1)) 2366 # define png_chunk_warning(s1,s2) ((void)(s1)) 2367 #endif 2368 2369 #ifdef PNG_BENIGN_ERRORS_SUPPORTED 2370 /* Benign error in libpng. Can continue, but may have a problem. 2371 * User can choose whether to handle as a fatal error or as a warning. */ 2372 PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr, 2373 png_const_charp warning_message)); 2374 2375 #ifdef PNG_READ_SUPPORTED 2376 /* Same, chunk name is prepended to message (only during read) */ 2377 PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr, 2378 png_const_charp warning_message)); 2379 #endif 2380 2381 #define png_set_error_action(png_ptr, what, action)\ 2382 (png_setting((png_ptr), PNG_SRW_ERROR_HANDLING, (what), (action))) 2383 /* Control the handling of 'benign' errors; errors that can be handled in 2384 * some way. The action is one of the following values: 2385 */ 2386 #define PNG_IGNORE 0 /* ignore the error; no warning or error message */ 2387 #define PNG_WARN 1 /* call png_warning with an appropriate error message */ 2388 #define PNG_ERROR 2 /* call png_error with the error message */ 2389 /* 'what' is a list (bit mask) of the errors to set: */ 2390 #define PNG_BENIGN_ERRORS (1U) 2391 #define PNG_APP_WARNINGS (2U) 2392 #define PNG_APP_ERRORS (4U) 2393 #define PNG_IDAT_ERRORS (8U) 2394 #define PNG_SAFE_ERRORS (PNG_BENIGN_ERRORS+PNG_APP_WARNINGS+PNG_APP_ERRORS) 2395 #define PNG_ALL_ERRORS (PNG_SAFE_ERRORS+PNG_IDAT_ERRORS) 2396 2397 PNG_REMOVED(109, void, png_set_benign_errors, 2398 (png_structrp png_ptr, int allowed), PNG_EMPTY) 2399 #define png_set_benign_errors(png_ptr, allowed) (png_setting((png_ptr),\ 2400 PNG_SRW_ERROR_HANDLING, PNG_SAFE_ERRORS,\ 2401 (allowed) ? PNG_WARN : PNG_ERROR)) 2402 /* Turn all errors that can be handled into warnings, or turn them back into 2403 * errors if 'allowed' is false. 2404 */ 2405 2406 #else 2407 # ifdef PNG_ALLOW_BENIGN_ERRORS 2408 # define png_benign_error(pp,e) png_warning(pp,e) 2409 # define png_chunk_benign_error(pp,e) png_chunk_warning(pp,e) 2410 # else 2411 # define png_benign_error(pp,e) png_error(pp,e) 2412 # define png_chunk_benign_error(pp,e) png_chunk_error(pp,e) 2413 # endif 2414 #endif 2415 2416 /* The png_set_<chunk> functions are for storing values in the png_info_struct. 2417 * Similarly, the png_get_<chunk> calls are used to read values from the 2418 * png_info_struct, either storing the parameters in the passed variables, or 2419 * setting pointers into the png_info_struct where the data is stored. The 2420 * png_get_<chunk> functions return a non-zero value if the data was available 2421 * in info_ptr, or return zero and do not change any of the parameters if the 2422 * data was not available. 2423 * 2424 * These functions should be used instead of directly accessing png_info 2425 * to avoid problems with future changes in the size and internal layout of 2426 * png_info_struct. 2427 */ 2428 /* Returns "flag" if chunk data is valid in info_ptr. */ 2429 PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr, 2430 png_const_inforp info_ptr, png_uint_32 flag)); 2431 2432 /* Returns number of bytes needed to hold a transformed row. */ 2433 PNG_EXPORT(111, png_alloc_size_t, png_get_rowbytes, (png_const_structrp png_ptr, 2434 png_const_inforp info_ptr)); 2435 2436 #ifdef PNG_READ_PNG_SUPPORTED 2437 /* Returns row_pointers, which is an array of pointers to scanlines that was 2438 * returned from png_read_png(). 2439 */ 2440 PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr, 2441 png_const_inforp info_ptr)); 2442 #endif 2443 2444 #ifdef PNG_WRITE_PNG_SUPPORTED 2445 /* Set row_pointers, which is an array of pointers to scanlines for use 2446 * by png_write_png(). 2447 */ 2448 PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr, 2449 png_inforp info_ptr, png_bytepp row_pointers)); 2450 #endif 2451 2452 /* Returns number of color channels in image. */ 2453 PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr, 2454 png_const_inforp info_ptr)); 2455 2456 #ifdef PNG_EASY_ACCESS_SUPPORTED 2457 /* Returns image width in pixels. */ 2458 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr, 2459 png_const_inforp info_ptr)); 2460 2461 /* Returns image height in pixels. */ 2462 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr, 2463 png_const_inforp info_ptr)); 2464 2465 /* Returns image bit_depth. */ 2466 PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr, 2467 png_const_inforp info_ptr)); 2468 2469 /* Returns image color_type. */ 2470 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr, 2471 png_const_inforp info_ptr)); 2472 2473 /* Returns image filter_type. */ 2474 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr, 2475 png_const_inforp info_ptr)); 2476 2477 /* Returns image interlace_type. */ 2478 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr, 2479 png_const_inforp info_ptr)); 2480 2481 /* Returns image compression_type. */ 2482 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr, 2483 png_const_inforp info_ptr)); 2484 2485 /* Returns image resolution in pixels per meter, from pHYs chunk data. */ 2486 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter, 2487 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2488 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter, 2489 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2490 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter, 2491 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2492 2493 /* Returns pixel aspect ratio, computed from pHYs chunk data. */ 2494 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio, 2495 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 2496 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed, 2497 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 2498 2499 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */ 2500 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels, 2501 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2502 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels, 2503 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2504 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns, 2505 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2506 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns, 2507 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2508 2509 #endif /* EASY_ACCESS */ 2510 2511 #ifdef PNG_READ_SUPPORTED 2512 /* Returns pointer to signature string read from PNG header */ 2513 PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr, 2514 png_const_inforp info_ptr)); 2515 #endif 2516 2517 #ifdef PNG_bKGD_SUPPORTED 2518 PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr, 2519 png_inforp info_ptr, png_color_16p *background)); 2520 #endif 2521 2522 #ifdef PNG_bKGD_SUPPORTED 2523 PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr, 2524 png_inforp info_ptr, png_const_color_16p background)); 2525 #endif 2526 2527 #ifdef PNG_cHRM_SUPPORTED 2528 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr, 2529 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x, 2530 double *red_y, double *green_x, double *green_y, double *blue_x, 2531 double *blue_y)) 2532 PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr, 2533 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z, 2534 double *green_X, double *green_Y, double *green_Z, double *blue_X, 2535 double *blue_Y, double *blue_Z)) 2536 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed, 2537 (png_const_structrp png_ptr, png_const_inforp info_ptr, 2538 png_fixed_point *int_white_x, png_fixed_point *int_white_y, 2539 png_fixed_point *int_red_x, png_fixed_point *int_red_y, 2540 png_fixed_point *int_green_x, png_fixed_point *int_green_y, 2541 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y)) 2542 PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed, 2543 (png_const_structrp png_ptr, png_const_inforp info_ptr, 2544 png_fixed_point *int_red_X, png_fixed_point *int_red_Y, 2545 png_fixed_point *int_red_Z, png_fixed_point *int_green_X, 2546 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z, 2547 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y, 2548 png_fixed_point *int_blue_Z)) 2549 #endif 2550 2551 #ifdef PNG_cHRM_SUPPORTED 2552 PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr, 2553 png_inforp info_ptr, 2554 double white_x, double white_y, double red_x, double red_y, double green_x, 2555 double green_y, double blue_x, double blue_y)) 2556 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr, 2557 png_inforp info_ptr, double red_X, double red_Y, double red_Z, 2558 double green_X, double green_Y, double green_Z, double blue_X, 2559 double blue_Y, double blue_Z)) 2560 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr, 2561 png_inforp info_ptr, png_fixed_point int_white_x, 2562 png_fixed_point int_white_y, png_fixed_point int_red_x, 2563 png_fixed_point int_red_y, png_fixed_point int_green_x, 2564 png_fixed_point int_green_y, png_fixed_point int_blue_x, 2565 png_fixed_point int_blue_y)) 2566 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr, 2567 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y, 2568 png_fixed_point int_red_Z, png_fixed_point int_green_X, 2569 png_fixed_point int_green_Y, png_fixed_point int_green_Z, 2570 png_fixed_point int_blue_X, png_fixed_point int_blue_Y, 2571 png_fixed_point int_blue_Z)) 2572 #endif 2573 2574 #ifdef PNG_gAMA_SUPPORTED 2575 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr, 2576 png_const_inforp info_ptr, double *file_gamma)) 2577 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed, 2578 (png_const_structrp png_ptr, png_const_inforp info_ptr, 2579 png_fixed_point *int_file_gamma)) 2580 #endif 2581 2582 #ifdef PNG_gAMA_SUPPORTED 2583 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr, 2584 png_inforp info_ptr, double file_gamma)) 2585 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr, 2586 png_inforp info_ptr, png_fixed_point int_file_gamma)) 2587 #endif 2588 2589 #ifdef PNG_hIST_SUPPORTED 2590 PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr, 2591 png_inforp info_ptr, png_uint_16p *hist)); 2592 #endif 2593 2594 #ifdef PNG_hIST_SUPPORTED 2595 PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr, 2596 png_inforp info_ptr, png_const_uint_16p hist)); 2597 #endif 2598 2599 PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr, 2600 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height, 2601 int *bit_depth, int *color_type, int *interlace_method, 2602 int *compression_method, int *filter_method)); 2603 2604 PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr, 2605 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, 2606 int color_type, int interlace_method, int compression_method, 2607 int filter_method)); 2608 2609 #ifdef PNG_oFFs_SUPPORTED 2610 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr, 2611 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y, 2612 int *unit_type)); 2613 #endif 2614 2615 #ifdef PNG_oFFs_SUPPORTED 2616 PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr, 2617 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y, 2618 int unit_type)); 2619 #endif 2620 2621 #ifdef PNG_pCAL_SUPPORTED 2622 PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr, 2623 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0, 2624 png_int_32 *X1, int *type, int *nparams, png_charp *units, 2625 png_charpp *params)); 2626 #endif 2627 2628 #ifdef PNG_pCAL_SUPPORTED 2629 PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr, 2630 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1, 2631 int type, int nparams, png_const_charp units, png_charpp params)); 2632 #endif 2633 2634 #ifdef PNG_pHYs_SUPPORTED 2635 PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr, 2636 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, 2637 int *unit_type)); 2638 #endif 2639 2640 #ifdef PNG_pHYs_SUPPORTED 2641 PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr, 2642 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type)); 2643 #endif 2644 2645 PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr, 2646 png_inforp info_ptr, png_colorp *palette, int *num_palette)); 2647 2648 PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr, 2649 png_inforp info_ptr, png_const_colorp palette, int num_palette)); 2650 2651 #ifdef PNG_sBIT_SUPPORTED 2652 PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr, 2653 png_inforp info_ptr, png_color_8p *sig_bit)); 2654 #endif 2655 2656 #ifdef PNG_sBIT_SUPPORTED 2657 PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr, 2658 png_inforp info_ptr, png_const_color_8p sig_bit)); 2659 #endif 2660 2661 #ifdef PNG_sRGB_SUPPORTED 2662 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr, 2663 png_const_inforp info_ptr, int *file_srgb_intent)); 2664 #endif 2665 2666 #ifdef PNG_sRGB_SUPPORTED 2667 PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr, 2668 png_inforp info_ptr, int srgb_intent)); 2669 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr, 2670 png_inforp info_ptr, int srgb_intent)); 2671 #endif 2672 2673 #ifdef PNG_iCCP_SUPPORTED 2674 PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr, 2675 png_inforp info_ptr, png_charpp name, int *compression_type, 2676 png_bytepp profile, png_uint_32 *proflen)); 2677 #endif 2678 2679 #ifdef PNG_iCCP_SUPPORTED 2680 PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr, 2681 png_inforp info_ptr, png_const_charp name, int compression_type, 2682 png_const_bytep profile, png_uint_32 proflen)); 2683 #endif 2684 2685 #ifdef PNG_sPLT_SUPPORTED 2686 PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr, 2687 png_inforp info_ptr, png_sPLT_tpp entries)); 2688 #endif 2689 2690 #ifdef PNG_sPLT_SUPPORTED 2691 PNG_EXPORT(161, void, png_set_sPLT, (png_structrp png_ptr, 2692 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)); 2693 #endif 2694 2695 #ifdef PNG_TEXT_SUPPORTED 2696 /* png_get_text also returns the number of text chunks in *num_text */ 2697 PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr, 2698 png_inforp info_ptr, png_textp *text_ptr, int *num_text)); 2699 #endif 2700 2701 /* Note while png_set_text() will accept a structure whose text, 2702 * language, and translated keywords are NULL pointers, the structure 2703 * returned by png_get_text will always contain regular 2704 * zero-terminated C strings. They might be empty strings but 2705 * they will never be NULL pointers. 2706 */ 2707 2708 #ifdef PNG_TEXT_SUPPORTED 2709 PNG_EXPORT(163, void, png_set_text, (png_structrp png_ptr, 2710 png_inforp info_ptr, png_const_textp text_ptr, int num_text)); 2711 #endif 2712 2713 #ifdef PNG_tIME_SUPPORTED 2714 PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr, 2715 png_inforp info_ptr, png_timep *mod_time)); 2716 #endif 2717 2718 #ifdef PNG_tIME_SUPPORTED 2719 PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr, 2720 png_inforp info_ptr, png_const_timep mod_time)); 2721 #endif 2722 2723 #ifdef PNG_tRNS_SUPPORTED 2724 PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr, 2725 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans, 2726 png_color_16p *trans_color)); 2727 #endif 2728 2729 #ifdef PNG_tRNS_SUPPORTED 2730 PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr, 2731 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans, 2732 png_const_color_16p trans_color)); 2733 #endif 2734 2735 #ifdef PNG_sCAL_SUPPORTED 2736 #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED 2737 /* NOTE: these API are currently implemented using floating point arithmetic, 2738 * consequently they can only be used on systems with floating point support. 2739 * In any case the range of values supported by png_fixed_point is small and it 2740 * is highly recommended that png_get_sCAL_s be used instead. 2741 */ 2742 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr, 2743 png_const_inforp info_ptr, int *unit, double *width, double *height)) 2744 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed, 2745 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, 2746 png_fixed_point *width, png_fixed_point *height)) 2747 #endif 2748 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s, 2749 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, 2750 png_charpp swidth, png_charpp sheight)); 2751 2752 #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED 2753 /* This also requires internal floating point arithmetic support - i.e. it 2754 * requires a full math library, not just floating point handling. 2755 */ 2756 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr, 2757 png_inforp info_ptr, int unit, double width, double height)) 2758 #endif 2759 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr, 2760 png_inforp info_ptr, int unit, png_fixed_point width, 2761 png_fixed_point height)) 2762 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr, 2763 png_inforp info_ptr, int unit, 2764 png_const_charp swidth, png_const_charp sheight)); 2765 #endif /* sCAL */ 2766 2767 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 2768 /* Provide the default handling for all unknown chunks or, optionally, for 2769 * specific unknown chunks. 2770 * 2771 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was 2772 * ignored and the default was used, the per-chunk setting only had an effect on 2773 * write. If you wish to have chunk-specific handling on read in code that must 2774 * work on earlier versions you must use a user chunk callback to implement the 2775 * desired handling (keep or discard.) 2776 * 2777 * NOTE: prior to 1.7.0 when a user callback returned '0', indicating that the 2778 * chunk had not been handled, libpng would preserve it regardless of the 2779 * default or per-chunk settings. For compatibility with earlier versions 2780 * simply return '1' (handled) from the callback to discard the chunk. 2781 * 2782 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The 2783 * parameter is interpreted as follows: 2784 * 2785 * READ: 2786 * PNG_HANDLE_CHUNK_AS_DEFAULT: 2787 * Known chunks: do normal libpng processing, do not keep the chunk (but 2788 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED) 2789 * Unknown chunks: for a specific chunk use the global default, when used 2790 * as the default discard the chunk data. 2791 * PNG_HANDLE_CHUNK_NEVER: 2792 * Discard the chunk data. 2793 * PNG_HANDLE_CHUNK_IF_SAFE: 2794 * Keep the chunk data if the chunk is not critical else raise a chunk 2795 * error. 2796 * PNG_HANDLE_CHUNK_ALWAYS: 2797 * Keep the chunk data. 2798 * 2799 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks, 2800 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent 2801 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks 2802 * it simply resets the behavior to the libpng default. 2803 * 2804 * The per-chunk handling is always used when there is a png_user_chunk_ptr 2805 * callback and the callback returns 0; the chunk is then always stored *unless* 2806 * it is critical and the per-chunk setting is other than ALWAYS. Notice that 2807 * the global default is *not* used in this case. (In effect the per-chunk 2808 * value is incremented to at least IF_SAFE.) 2809 * 2810 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED: 2811 * If this is *not* set known chunks will always be handled by libpng and 2812 * will never be stored in the unknown chunk list. Known chunks listed to 2813 * png_set_keep_unknown_chunks will have no effect. If it is set then known 2814 * chunks listed with a keep other than AS_DEFAULT will *never* be processed 2815 * by libpng, in addition critical chunks must either be processed by the 2816 * callback or saved. 2817 * 2818 * The IHDR and IEND chunks must not be listed. Because this turns off the 2819 * default handling for chunks that would otherwise be recognized the 2820 * behavior of libpng transformations may well become incorrect! 2821 * 2822 * WRITE: 2823 * When writing chunks the options only apply to the chunks specified by 2824 * png_set_unknown_chunks (below), libpng will *always* write known chunks 2825 * required by png_set_ calls and will always write the core critical chunks 2826 * (as required for PLTE). 2827 * 2828 * Each chunk in the png_set_unknown_chunks list is looked up in the 2829 * png_set_keep_unknown_chunks list to find the keep setting, this is then 2830 * interpreted as follows: 2831 * 2832 * PNG_HANDLE_CHUNK_AS_DEFAULT: 2833 * Write safe-to-copy chunks and write other chunks if the global 2834 * default is set to _ALWAYS, otherwise don't write this chunk. 2835 * PNG_HANDLE_CHUNK_NEVER: 2836 * Do not write the chunk. 2837 * PNG_HANDLE_CHUNK_IF_SAFE: 2838 * Write the chunk if it is safe-to-copy, otherwise do not write it. 2839 * PNG_HANDLE_CHUNK_ALWAYS: 2840 * Write the chunk. 2841 * 2842 * Note that the default behavior is effectively the opposite of the read case - 2843 * in read unknown chunks are not stored by default, in write they are written 2844 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different 2845 * - on write the safe-to-copy bit is checked, on read the critical bit is 2846 * checked and on read if the chunk is critical an error will be raised. 2847 * 2848 * num_chunks: 2849 * =========== 2850 * If num_chunks is positive, then the "keep" parameter specifies the manner 2851 * for handling only those chunks appearing in the chunk_list array, 2852 * otherwise the chunk list array is ignored. 2853 * 2854 * If num_chunks is 0 the "keep" parameter specifies the default behavior for 2855 * unknown chunks, as described above. 2856 * 2857 * If num_chunks is negative, then the "keep" parameter specifies the manner 2858 * for handling all unknown chunks plus all chunks recognized by libpng 2859 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to 2860 * be processed by libpng. 2861 */ 2862 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 2863 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr, 2864 int keep, png_const_bytep chunk_list, int num_chunks)); 2865 #endif /* HANDLE_AS_UNKNOWN */ 2866 2867 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned; 2868 * the result is therefore true (non-zero) if special handling is required, 2869 * false for the default handling. 2870 */ 2871 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr, 2872 png_const_bytep chunk_name)); 2873 #endif /* SET_UNKNOWN_CHUNKS */ 2874 2875 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 2876 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_structrp png_ptr, 2877 png_inforp info_ptr, png_const_unknown_chunkp unknowns, 2878 int num_unknowns)); 2879 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added 2880 * unknowns to the location currently stored in the png_struct. This is 2881 * invariably the wrong value on write. To fix this call the following API 2882 * for each chunk in the list with the correct location. If you know your 2883 * code won't be compiled on earlier versions you can rely on 2884 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing 2885 * the correct thing. 2886 * 2887 * API CHANGE: in 1.7.0 this API will not work on read unless 2888 * PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED is set; it may be necessary to change 2889 * code to check the latter SUPPORTED flag. png_set_keep_unknown_chunks 2890 * will issue a warning if it is asked to save a chunk and there is no read 2891 * support. 2892 */ 2893 2894 PNG_EXPORT(175, void, png_set_unknown_chunk_location, 2895 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location)); 2896 2897 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr, 2898 png_inforp info_ptr, png_unknown_chunkpp entries)); 2899 #endif 2900 2901 /* Png_free_data() will turn off the "valid" flag for anything it frees. 2902 * If you need to turn it off for a chunk that your application has freed, 2903 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); 2904 */ 2905 PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr, 2906 png_inforp info_ptr, int mask)); 2907 2908 /* The "params" pointer is currently not used and is for future expansion. */ 2909 #ifdef PNG_READ_PNG_SUPPORTED 2910 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr, 2911 int transforms, png_voidp params)); 2912 #endif 2913 #ifdef PNG_WRITE_PNG_SUPPORTED 2914 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr, 2915 int transforms, png_voidp params)); 2916 #endif 2917 2918 PNG_EXPORT(180, png_const_charp, png_get_copyright, 2919 (png_const_structrp png_ptr)); 2920 PNG_EXPORT(181, png_const_charp, png_get_header_ver, 2921 (png_const_structrp png_ptr)); 2922 PNG_EXPORT(182, png_const_charp, png_get_header_version, 2923 (png_const_structrp png_ptr)); 2924 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver, 2925 (png_const_structrp png_ptr)); 2926 2927 #ifdef PNG_MNG_FEATURES_SUPPORTED 2928 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr, 2929 png_uint_32 mng_features_permitted)); 2930 #endif 2931 2932 /* For use in png_set_keep_unknown, added to version 1.2.6 */ 2933 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0 2934 #define PNG_HANDLE_CHUNK_NEVER 1 2935 #define PNG_HANDLE_CHUNK_IF_SAFE 2 2936 #define PNG_HANDLE_CHUNK_ALWAYS 3 2937 #define PNG_HANDLE_CHUNK_LAST 4 2938 2939 #ifdef PNG_ERROR_NUMBERS_SUPPORTED 2940 /* This was never implemented: */ 2941 PNG_REMOVED(185, void, png_set_strip_error_numbers, (png_structrp png_ptr, 2942 png_uint_32 strip_mode), PNG_EMPTY) 2943 #endif 2944 2945 /* Added in libpng-1.2.6 */ 2946 #ifdef PNG_SET_USER_LIMITS_SUPPORTED 2947 PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr, 2948 png_uint_32 user_width_max, png_uint_32 user_height_max)); 2949 PNG_EXPORT(187, png_uint_32, png_get_user_width_max, 2950 (png_const_structrp png_ptr)); 2951 PNG_EXPORT(188, png_uint_32, png_get_user_height_max, 2952 (png_const_structrp png_ptr)); 2953 /* Added in libpng-1.4.0 */ 2954 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr, 2955 png_uint_32 user_chunk_cache_max)); 2956 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max, 2957 (png_const_structrp png_ptr)); 2958 /* Added in libpng-1.4.1 */ 2959 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr, 2960 png_alloc_size_t user_chunk_cache_max)); 2961 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max, 2962 (png_const_structrp png_ptr)); 2963 #endif 2964 2965 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED) 2966 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch, 2967 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2968 2969 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch, 2970 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2971 2972 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch, 2973 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 2974 2975 PNG_FP_EXPORT(196, float, png_get_x_offset_inches, 2976 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 2977 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ 2978 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed, 2979 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 2980 #endif 2981 2982 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr, 2983 png_const_inforp info_ptr)) 2984 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ 2985 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed, 2986 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 2987 #endif 2988 2989 # ifdef PNG_pHYs_SUPPORTED 2990 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr, 2991 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, 2992 int *unit_type)); 2993 # endif /* pHYs */ 2994 #endif /* INCH_CONVERSIONS */ 2995 2996 /* Added in libpng-1.4.0 */ 2997 #ifdef PNG_IO_STATE_SUPPORTED 2998 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr)); 2999 3000 /* Removed from libpng 1.6; use png_get_io_chunk_type. */ 3001 PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr), 3002 PNG_DEPRECATED) 3003 3004 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type, 3005 (png_const_structrp png_ptr)); 3006 3007 /* The flags returned by png_get_io_state() are the following: */ 3008 # define PNG_IO_NONE 0x0000U /* no I/O at this moment */ 3009 # define PNG_IO_READING 0x0001U /* currently reading */ 3010 # define PNG_IO_WRITING 0x0002U /* currently writing */ 3011 # define PNG_IO_SIGNATURE 0x0010U /* currently at the file signature */ 3012 # define PNG_IO_CHUNK_HDR 0x0020U /* currently at the chunk header */ 3013 # define PNG_IO_CHUNK_DATA 0x0040U /* currently at the chunk data */ 3014 # define PNG_IO_CHUNK_CRC 0x0080U /* currently at the chunk crc */ 3015 # define PNG_IO_MASK_OP 0x000fU /* current operation: reading/writing */ 3016 # define PNG_IO_MASK_LOC 0x00f0U /* current location: sig/hdr/data/crc */ 3017 #endif /* IO_STATE */ 3018 3019 /* Interlace support. The following macros are always defined so that if 3020 * libpng interlace handling is turned off the macros may be used to handle 3021 * interlaced images within the application. 3022 */ 3023 #define PNG_INTERLACE_ADAM7_PASSES 7 3024 3025 /* Two macros to return the first row and first column of the original, 3026 * full, image which appears in a given pass. 'pass' is in the range 0 3027 * to 6 and the result is in the range 0 to 7. 3028 */ 3029 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7) 3030 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7) 3031 3032 /* A macro to return the offset between pixels in the output row for a pair of 3033 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that 3034 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas 3035 * COL_OFFSET is from one column to the next, within a row. 3036 */ 3037 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8) 3038 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1)) 3039 3040 /* Two macros to help evaluate the number of rows or columns in each 3041 * pass. This is expressed as a shift - effectively 3-log2 of the number or 3042 * rows or columns in each 8x8 tile of the original image. 3043 */ 3044 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3) 3045 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3) 3046 3047 /* Hence two macros to determine the number of rows or columns in a given 3048 * pass of an image given its height or width. In fact these macros may 3049 * return non-zero even though the sub-image is empty, because the other 3050 * dimension may be empty for a small image. 3051 */ 3052 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\ 3053 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass)) 3054 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\ 3055 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass)) 3056 3057 /* For the reader row callbacks (both progressive and sequential) it is 3058 * necessary to find the row in the output image given a row in an interlaced 3059 * image, so two more macros: 3060 */ 3061 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \ 3062 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass)) 3063 #define PNG_COL_FROM_PASS_COL(x_in, pass) \ 3064 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass)) 3065 3066 /* Two macros which return a boolean (0 or 1) saying whether the given row 3067 * or column is in a particular pass. These use a common utility macro that 3068 * returns a mask for a given pass - the offset 'off' selects the row or 3069 * column version. The mask has the appropriate bit set for each column in 3070 * the tile. 3071 */ 3072 #define PNG_PASS_MASK(pass,off) ( \ 3073 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \ 3074 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0)) 3075 3076 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \ 3077 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1) 3078 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \ 3079 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1) 3080 3081 /* Whether the pass is in the image at all, taking into account the full image 3082 * width and height, evaluates 'pass' lots of times, but width and height at 3083 * most once each. 3084 */ 3085 #define PNG_PASS_IN_IMAGE(width, height, pass)\ 3086 ((height) > PNG_PASS_START_ROW(pass) && (width) > PNG_PASS_START_COL(pass)) 3087 3088 /* A macro to find the last pass (in the range 0 to 6) given an image width and 3089 * height. Then two macros two find whether a given image row or column which 3090 * is present in the pass is the last row or column in the pass. Note that 3091 * these macros return 'true' for earlier rows or columns of the image that are 3092 * *not* in the pass. 3093 */ 3094 #define PNG_LAST_PASS(width, height) ((height) > 1 ? 6 : ((width) > 1 ? 5 : 0)) 3095 #define PNG_LAST_PASS_ROW(y, pass, height)\ 3096 ((y) + PNG_PASS_ROW_OFFSET(pass) >= (height)) 3097 #define PNG_LAST_PASS_COL(x, pass, width)\ 3098 ((x) + PNG_PASS_COL_OFFSET(pass) >= (width)) 3099 3100 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED 3101 /* With these routines we avoid an integer divide, which will be slower on 3102 * most machines. However, it does take more operations than the corresponding 3103 * divide method, so it may be slower on a few RISC systems. There are two 3104 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide. 3105 * 3106 * Note that the rounding factors are NOT supposed to be the same! 128 and 3107 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the 3108 * standard method. 3109 * 3110 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ] 3111 */ 3112 3113 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */ 3114 3115 # define png_composite(composite, fg, alpha, bg) \ 3116 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \ 3117 * (png_uint_16)(alpha) \ 3118 + (png_uint_16)(bg)*(png_uint_16)(255 \ 3119 - (png_uint_16)(alpha)) + 128); \ 3120 (composite) = (png_byte)((temp + (temp >> 8)) >> 8); } 3121 3122 # define png_composite_16(composite, fg, alpha, bg) \ 3123 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \ 3124 * (png_uint_32)(alpha) \ 3125 + (png_uint_32)(bg)*(65535 \ 3126 - (png_uint_32)(alpha)) + 32768); \ 3127 (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); } 3128 3129 #else /* Standard method using integer division */ 3130 3131 # define png_composite(composite, fg, alpha, bg) \ 3132 (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \ 3133 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \ 3134 127) / 255) 3135 3136 # define png_composite_16(composite, fg, alpha, bg) \ 3137 (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \ 3138 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \ 3139 32767) / 65535) 3140 #endif /* READ_COMPOSITE_NODIV */ 3141 3142 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED 3143 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf)); 3144 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf)); 3145 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf)); 3146 #endif 3147 3148 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr, 3149 png_const_bytep buf)); 3150 /* No png_get_int_16 -- may be added if there's a real need for it. */ 3151 3152 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */ 3153 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED 3154 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i)); 3155 3156 /* This becomes a macro in 1.7 because the old implementation was wrong; it 3157 * failed to do the cast. ANSI C requires the cast to convert a negative number 3158 * to the 2's complement form, so this just works: 3159 */ 3160 #define png_save_int_32(b, i) png_save_uint_32(b, i); 3161 #endif /* WRITE_INT_FUNCTIONS */ 3162 3163 /* Apps that used this will use the macro in 1.7. */ 3164 PNG_REMOVED(206, void, png_save_int_32, (png_bytep buf, png_int_32 i), 3165 PNG_DEPRECATED) 3166 3167 /* Place a 16-bit number into a buffer in PNG byte order. 3168 * The parameter is declared unsigned int, not png_uint_16, 3169 * just to avoid potential problems on pre-ANSI C compilers. 3170 */ 3171 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED 3172 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i)); 3173 /* No png_save_int_16 -- may be added if there's a real need for it. */ 3174 #endif 3175 3176 #ifdef PNG_USE_READ_MACROS 3177 /* Inline macros to do direct reads of bytes from the input buffer. 3178 */ 3179 # define PNG_B(ptr, offset) (((png_const_bytep)(ptr))[offset]) 3180 # define PNG_get_uint_32(buf) \ 3181 PNG_U32(PNG_B(buf,0), PNG_B(buf,1), PNG_B(buf,2), PNG_B(buf,3)) 3182 3183 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the 3184 * function) incorrectly returned a value of type png_uint_32. 3185 */ 3186 # define PNG_get_uint_16(buf) PNG_U16(PNG_B(buf,0), PNG_B(buf,1)) 3187 3188 # define PNG_get_int_32(buf) \ 3189 PNG_S32(PNG_B(buf,0), PNG_B(buf,1), PNG_B(buf,2), PNG_B(buf,3)) 3190 3191 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h, 3192 * but defining a macro name prefixed with PNG_PREFIX. 3193 */ 3194 # ifndef PNG_PREFIX 3195 # define png_get_uint_32(buf) PNG_get_uint_32(buf) 3196 # define png_get_uint_16(buf) PNG_get_uint_16(buf) 3197 # define png_get_int_32(buf) PNG_get_int_32(buf) 3198 # endif 3199 #else 3200 # ifdef PNG_PREFIX 3201 /* No macros; revert to the (redefined) function */ 3202 # define PNG_get_uint_32 (png_get_uint_32) 3203 # define PNG_get_uint_16 (png_get_uint_16) 3204 # define PNG_get_int_32 (png_get_int_32) 3205 # endif 3206 #endif 3207 3208 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED 3209 PNG_REMOVED(242, void, png_set_check_for_invalid_index, 3210 (png_structrp png_ptr, int enabled_if_greater_than_0), PNG_EMPTY) 3211 #define png_set_check_for_invalid_index(png_ptr, value)\ 3212 (png_setting((png_ptr), PNG_SRW_CHECK_FOR_INVALID_INDEX, 0, (value))) 3213 /* By default the check is enabled on both read and write when the number of 3214 * entries in the palette is less than the maximum required by the bit depth 3215 * of a palette image. 3216 * 3217 * Passing 1 to 'enabled' turns the check on in all cases. 3218 * Passing -1 turns it off and the PNG may have invalid palette index values. 3219 * Passing 0 restores the default. 3220 * 3221 * On read chunk (benign) error messages are only produced with the default 3222 * setting; it is assumed that when the check is turned on explicitly the 3223 * caller will call png_get_palette_max to check the result. 3224 * 3225 * The png_setting call returns 0. 3226 */ 3227 #endif /* CHECK_FOR_INVALID_INDEX */ 3228 #ifdef PNG_GET_PALETTE_MAX_SUPPORTED 3229 PNG_EXPORT(243, int, png_get_palette_max, (png_const_structrp png_ptr, 3230 png_const_inforp info_ptr)); 3231 /* The info_ptr is not used, it may be NULL in 1.7.0 (not in earlier 3232 * versions). If the information is not available because 3233 * png_set_check_for_invalid_index was not used to turn it on -1 is returned. 3234 * Valid results can only be obtained after the complete image has been read, 3235 * though it may be called at any time to get the result so far. 3236 */ 3237 #endif /* GET_PALETTE_MAX */ 3238 3239 /* Memory format options; these return information about the layout of the 3240 * transformed row using the Simplified API PNG_FORMAT_ values (see below for 3241 * the #defines). 3242 * 3243 * These are only relevant if read or write transforms are supported; these 3244 * may cause the memory format of pixel data to differ from that used in the 3245 * PNG file itself. Nevertheless the APIs are supported regardless of whether 3246 * transforms are applied; use these to consistently and safely determine the 3247 * layout of the image in memory. 3248 * 3249 * Some of the same information can be obtained from png_info, however this 3250 * does not record whether the byte or bit formats have been changed. 3251 */ 3252 PNG_EXPORT(246, unsigned int, png_memory_format, (png_structrp png_ptr)); 3253 /* The in-memory format as a bitmask of PNG_FORMAT_FLAG_ values. All the 3254 * flags listed below are used. If PNG_FORMAT_FLAG_INVALID is set the 3255 * following caveats apply to the interpretation of PNG_FORMAT_FLAG_LINEAR: 3256 * 3257 * The gamma may differ from the sRGB (!LINEAR) or 1.0 (LINEAR). Call 3258 * png_memory_gamma to find the correct value. 3259 * 3260 * The channel depth may differ from 8 (!LINEAR) or 16 (LINEAR). Call 3261 * png_memory_channel_depth to find the correct value. 3262 * 3263 * It is only valid to call these APIS *after* either png_read_update_info 3264 * or png_start_read_image on read or after the first row of an image has 3265 * been written on write. 3266 * 3267 * To find the number of channels in each pixel from the returned value, 3268 * 'fmt' use: 3269 * 3270 * PNG_FORMAT_CHANNELS(fmt) 3271 */ 3272 3273 PNG_EXPORT(247, unsigned int, png_memory_channel_depth, (png_structrp png_ptr)); 3274 /* The actual depth of each channel in the image, to determine the full pixel 3275 * depth (in bits) use: 3276 * 3277 * png_memory_channel_depth(pp) * PNG_FORMAT_CHANNELS(fmt) 3278 */ 3279 3280 #ifdef PNG_GAMMA_SUPPORTED 3281 PNG_EXPORT(248, png_fixed_point, png_memory_gamma, (png_structrp png_ptr)); 3282 /* The actual gamma of the image data, scaled by 100,000. This is the 3283 * encoding gamma, e.g. 1/2.2 for sRGB. If the gamma is unknown this will 3284 * return 0. 3285 * 3286 * On write this invariably returns 0; libpng does not change the gamma of 3287 * the data on write. 3288 * 3289 * Note that this is not always the exact inverse of the 'screen gamma' 3290 * passed to png_set_gamma; internal optimizations remove attempts to make 3291 * small changes to the gamma value. This function returns the actual 3292 * output value. 3293 */ 3294 #endif /* GAMMA */ 3295 3296 /******************************************************************************* 3297 * Section 5: SIMPLIFIED API 3298 ******************************************************************************* 3299 * 3300 * Please read the documentation in libpng-manual.txt (TODO: write said 3301 * documentation) if you don't understand what follows. 3302 * 3303 * The simplified API hides the details of both libpng and the PNG file format 3304 * itself. It allows PNG files to be read into a very limited number of 3305 * in-memory bitmap formats or to be written from the same formats. If these 3306 * formats do not accomodate your needs then you can, and should, use the more 3307 * sophisticated APIs above - these support a wide variety of in-memory formats 3308 * and a wide variety of sophisticated transformations to those formats as well 3309 * as a wide variety of APIs to manipulate ancillary information. 3310 * 3311 * To read a PNG file using the simplified API: 3312 * 3313 * 1) Declare a 'png_image' structure (see below) on the stack and set the 3314 * version field to PNG_IMAGE_VERSION. 3315 * 2) Call the appropriate png_image_begin_read... function. 3316 * 3) Set the png_image 'format' member to the required sample format. 3317 * 4) Allocate a buffer for the image and, if required, the color-map. 3318 * 5) Call png_image_finish_read to read the image and, if required, the 3319 * color-map into your buffers. 3320 * 3321 * There are no restrictions on the format of the PNG input itself; all valid 3322 * color types, bit depths, and interlace methods are acceptable, and the 3323 * input image is transformed as necessary to the requested in-memory format 3324 * during the png_image_finish_read() step. The only caveat is that if you 3325 * request a color-mapped image from a PNG that is full-color or makes 3326 * complex use of an alpha channel the transformation is extremely lossy and the 3327 * result may look terrible. 3328 * 3329 * To write a PNG file using the simplified API: 3330 * 3331 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero. 3332 * 2) Initialize the members of the structure that describe the image, setting 3333 * the 'format' member to the format of the image samples. 3334 * 3) Call the appropriate png_image_write... function with a pointer to the 3335 * image and, if necessary, the color-map to write the PNG data. 3336 * 3337 * png_image is a structure that describes the in-memory format of an image 3338 * when it is being read or defines the in-memory format of an image that you 3339 * need to write: 3340 */ 3341 #define PNG_IMAGE_VERSION 1 3342 3343 typedef struct png_control *png_controlp; 3344 typedef struct 3345 { 3346 png_controlp opaque; /* Initialize to NULL, free with png_image_free */ 3347 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */ 3348 png_uint_32 width; /* Image width in pixels (columns) */ 3349 png_uint_32 height; /* Image height in pixels (rows) */ 3350 png_uint_32 format; /* Image format as defined below */ 3351 png_uint_32 flags; /* A bit mask containing informational flags */ 3352 png_uint_32 colormap_entries; 3353 /* Number of entries in the color-map */ 3354 3355 /* In the event of an error or warning the following field will be set to a 3356 * non-zero value and the 'message' field will contain a '\0' terminated 3357 * string with the libpng error or warning message. If both warnings and 3358 * an error were encountered, only the error is recorded. If there 3359 * are multiple warnings, only the first one is recorded. 3360 * 3361 * The upper 30 bits of this value are reserved, the low two bits contain 3362 * a value as follows: 3363 */ 3364 # define PNG_IMAGE_WARNING 1 3365 # define PNG_IMAGE_ERROR 2 3366 /* 3367 * The result is a two-bit code such that a value more than 1 indicates 3368 * a failure in the API just called: 3369 * 3370 * 0 - no warning or error 3371 * 1 - warning 3372 * 2 - error 3373 * 3 - error preceded by warning 3374 */ 3375 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1) 3376 3377 png_uint_32 warning_or_error; 3378 3379 char message[64]; 3380 } png_image, *png_imagep; 3381 3382 /* The samples of the image have one to four channels whose components have 3383 * original values in the range 0 to 1.0: 3384 * 3385 * 1: A single gray or luminance channel (G). 3386 * 2: A gray/luminance channel and an alpha channel (GA). 3387 * 3: Three red, green, blue color channels (RGB). 3388 * 4: Three color channels and an alpha channel (RGBA). 3389 * 3390 * The components are encoded in one of two ways: 3391 * 3392 * a) As a small integer, value 0..255, contained in a single byte. For the 3393 * alpha channel the original value is simply value/255. For the color or 3394 * luminance channels the value is encoded according to the sRGB specification 3395 * and matches the 8-bit format expected by typical display devices. 3396 * 3397 * The color/gray channels are not scaled (pre-multiplied) by the alpha 3398 * channel and are suitable for passing to color management software. 3399 * 3400 * b) As a value in the range 0..65535, contained in a 2-byte integer. All 3401 * channels can be converted to the original value by dividing by 65535; all 3402 * channels are linear. Color channels use the RGB encoding (RGB end-points) of 3403 * the sRGB specification. This encoding is identified by the 3404 * PNG_FORMAT_FLAG_LINEAR flag below. 3405 * 3406 * When the simplified API needs to convert between sRGB and linear colorspaces, 3407 * the actual sRGB transfer curve defined in the sRGB specification (see the 3408 * article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2 3409 * approximation used elsewhere in libpng. 3410 * 3411 * When an alpha channel is present it is expected to denote pixel coverage 3412 * of the color or luminance channels and is returned as an associated alpha 3413 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha 3414 * value. 3415 * 3416 * The samples are either contained directly in the image data, between 1 and 8 3417 * bytes per pixel according to the encoding, or are held in a color-map indexed 3418 * by bytes in the image data. In the case of a color-map the color-map entries 3419 * are individual samples, encoded as above, and the image data has one byte per 3420 * pixel to select the relevant sample from the color-map. 3421 */ 3422 3423 /* PNG_FORMAT_* 3424 * 3425 * #defines to be used in png_image::format. Each #define identifies a 3426 * particular layout of sample data and, if present, alpha values. There are 3427 * separate defines for each of the two component encodings. 3428 * 3429 * A format is built up using single bit flag values. All combinations are 3430 * valid. Formats can be built up from the flag values or you can use one of 3431 * the predefined values below. When testing formats always use the FORMAT_FLAG 3432 * macros to test for individual features - future versions of the library may 3433 * add new flags. 3434 * 3435 * When reading or writing color-mapped images the format should be set to the 3436 * format of the entries in the color-map then png_image_{read,write}_colormap 3437 * called to read or write the color-map and set the format correctly for the 3438 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly! 3439 * 3440 * NOTE: libpng can be built with particular features disabled, if you see 3441 * compiler errors because the definition of one of the following flags has been 3442 * compiled out it is because libpng does not have the required support. It is 3443 * possible, however, for the libpng configuration to enable the format on just 3444 * read or just write; in that case you may see an error at run time. You can 3445 * guard against this by checking for the definition of the appropriate 3446 * "_SUPPORTED" macro, one of: 3447 * 3448 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED 3449 */ 3450 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */ 3451 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */ 3452 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2 byte channels else 1 byte */ 3453 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */ 3454 #define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */ 3455 #define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */ 3456 /* other bits RESERVED */ 3457 3458 /* The PNG color type value can be derived from a format which repesents a valid 3459 * PNG format using the following macro. Note that if any of the non-PNG 3460 * format elements are use, such as BGR or AFIRST, the color type value that 3461 * results does represent the number of channels in the format but may not 3462 * represent their order or encoding. 3463 * 3464 * NOTE: the format can encode illegal PNG formats, such as a colormap with 3465 * alpha or without color; these are legal simplified API formats which produce 3466 * data that cannot be represented as PNG regardless of channel order or 3467 * encoding. 3468 * 3469 * The macro below is the bit shift version, a multiplicative version which only 3470 * evaluates 'f' once is: 3471 * 3472 * ((((((((f) * 0x111) & 0x128) * 0x3) & 0x130) * 0x5) >> 6) & 0x7) 3473 */ 3474 #define PNG_COLOR_TYPE_FROM_FORMAT(f)\ 3475 ((((f) & (!((f) & PNG_FORMAT_FLAG_AFILLER))) << 2) |\ 3476 (((f) & PNG_FORMAT_FLAG_COLOR) ) |\ 3477 (((f) & PNG_FORMAT_FLAG_COLORMAP) >> 3)) 3478 3479 /* The inverse: note that PNG_FORMAT_FLAG_LINEAR is not set by this macro and 3480 * that there is no handling for a 'filler' channel, consequently the macro must 3481 * only be used on genuine PNG color types, not the result of png_get_color_type 3482 * after transforms have been applied to the original PNG data. 3483 */ 3484 #define PNG_FORMAT_FROM_COLOR_TYPE(c)\ 3485 ((((c) & PNG_COLOR_MASK_ALPHA) >> 2) |\ 3486 (((c) & PNG_COLOR_MASK_COLOR) ) |\ 3487 (((c) & PNG_COLOR_MASK_PALETTE) << 3)) 3488 3489 /* The following flags are not used by the simplified API but may be returned 3490 * by png_memory_format. Presence of any of these flags means that the values 3491 * in the image (in memory) cannot be handled 'normally'. 3492 */ 3493 #define PNG_FORMAT_FLAG_AFILLER 0x40U /* The 'alpha' channel is a filler: 3494 * PNG_FORMAT_FLAG_ALPHA is set however the value in the alpha channel 3495 * is not an alpha value and (therefore) cannot be used for alpha 3496 * computations, it is just a filler value. PNG_COLOR_TYPE_FROM_FORMAT 3497 * will return a color type *without* PNG_COLOR_MASK_ALPHA, however 3498 * PNG_FORMAT_CHANNELS will return the correct number, including the 3499 * filler channel. 3500 */ 3501 #define PNG_FORMAT_FLAG_SWAPPED 0x80U /* bytes or bits swapped: 3502 * When the bit depth is 16 this means that the bytes within the 3503 * components have been swapped, when the bit depth is less than 8 3504 * it means the pixels within the bytes have been swapped. It should 3505 * not be set for 8-bit compononents (it is meaningless). */ 3506 #define PNG_FORMAT_FLAG_RANGE 0x100U /* component range not 0..bit-depth: 3507 * Low-bit-depth grayscale components have been unpacked into bytes 3508 * without scaling, or RGB[A] pixels have been shifted back to the 3509 * significant-bit range from the sBIT chunk or channels (currently 3510 * alpha or gray) have been inverted. */ 3511 #define PNG_FORMAT_FLAG_INVALID 0x8000U /* Invalid simplified API channel depth: 3512 * For single channel grayscale and palette indexed image data PNG 3513 * supports bit depths of 1, 2 or 4 bits per pixel (and per channel) 3514 * packed into bytes. The simplified API macros will not work with 3515 * these formats (the simplified API always uses 8 or 16-bit channels). 3516 * In the simplified API 'linear' images always have 16-bit channels 3517 * and non-linear images are always sRGB encoded. If the INVALID flag 3518 * is set then this may not be true; it is necessary to check the 3519 * memory format bit-depth and gamma separately. 3520 */ 3521 3522 /* Commonly used formats have predefined macros. 3523 * 3524 * First the single byte (sRGB) formats: 3525 */ 3526 #define PNG_FORMAT_GRAY 0U 3527 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA 3528 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST) 3529 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR 3530 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR) 3531 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA) 3532 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST) 3533 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA) 3534 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST) 3535 3536 /* Then the linear 2-byte formats. When naming these "Y" is used to 3537 * indicate a luminance (gray) channel. 3538 */ 3539 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR 3540 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA) 3541 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR) 3542 #define PNG_FORMAT_LINEAR_RGB_ALPHA \ 3543 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA) 3544 3545 /* With color-mapped formats the image data is one byte for each pixel, the byte 3546 * is an index into the color-map which is formatted as above. To obtain a 3547 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP 3548 * to one of the above definitions, or you can use one of the definitions below. 3549 */ 3550 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP) 3551 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP) 3552 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP) 3553 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP) 3554 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP) 3555 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP) 3556 3557 /* PNG_IMAGE macros 3558 * 3559 * These are convenience macros to derive information from a png_image 3560 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the 3561 * actual image sample values - either the entries in the color-map or the 3562 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values 3563 * for the pixels and will always return 1 for color-mapped formats. The 3564 * remaining macros return information about the rows in the image and the 3565 * complete image. 3566 * 3567 * NOTE: All the macros that take a png_image::format parameter are compile time 3568 * constants if the format parameter is, itself, a constant. Therefore these 3569 * macros can be used in array declarations and case labels where required. 3570 * Similarly the macros are also pre-processor constants (sizeof is not used) so 3571 * they can be used in #if tests. 3572 * 3573 * First the information about the samples. 3574 */ 3575 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\ 3576 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1) 3577 /* Return the total number of channels in a given format: 1..4 */ 3578 3579 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\ 3580 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1) 3581 /* Return the size in bytes of a single component of a pixel or color-map 3582 * entry (as appropriate) in the image: 1 or 2. 3583 */ 3584 3585 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\ 3586 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)) 3587 /* This is the size of the sample data for one sample. If the image is 3588 * color-mapped it is the size of one color-map entry (and image pixels are 3589 * one byte in size), otherwise it is the size of one image pixel. 3590 */ 3591 3592 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\ 3593 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256) 3594 /* The maximum size of the color-map required by the format expressed in a 3595 * count of components. This can be used to compile-time allocate a 3596 * color-map: 3597 * 3598 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)]; 3599 * 3600 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)]; 3601 * 3602 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the 3603 * information from one of the png_image_begin_read_ APIs and dynamically 3604 * allocate the required memory. 3605 */ 3606 3607 /* Corresponding information about the pixels */ 3608 #define PNG_IMAGE_PIXEL_(test,fmt)\ 3609 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt)) 3610 3611 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\ 3612 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt) 3613 /* The number of separate channels (components) in a pixel; 1 for a 3614 * color-mapped image. 3615 */ 3616 3617 #define PNG_FORMAT_CHANNELS(fmt) PNG_IMAGE_PIXEL_CHANNELS(fmt) 3618 /* Synonym for the above for use with the result of png_get_memory_format. 3619 * This exists to avoid confusion with the PNG_IMAGE_ macros which do not 3620 * work on all possible results of png_get_memory_format. 3621 */ 3622 3623 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\ 3624 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt) 3625 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped 3626 * image. 3627 */ 3628 3629 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt) 3630 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */ 3631 3632 /* Information about the whole row, or whole image */ 3633 #define PNG_IMAGE_ROW_STRIDE(image)\ 3634 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (png_alloc_size_t)(image).width) 3635 /* Return the total number of components in a single row of the image; this 3636 * is the minimum 'row stride', the minimum count of components between each 3637 * row. For a color-mapped image this is the minimum number of bytes in a 3638 * row. 3639 * 3640 * WARNING: libpng 1.7: this macro now returns a png_alloc_size_t, previous 3641 * versions returned a png_uint_32 and could overflow for images that fit in 3642 * memory. This macro can still overflow, but if it does the row will not 3643 * fit in memory. The simplified API functions detect this and refuse to 3644 * handle the image. 3645 */ 3646 3647 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\ 3648 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride)) 3649 /* Return the size, in bytes, of an image buffer given a png_image and a row 3650 * stride - the number of components to leave space for in each row. 3651 * 3652 * WARNING: This is the total size of the image, for large images it will 3653 * overflow on a 32-bit system. In libpng 1.7 (but not before) it returns a 3654 * png_alloc_size_t which means that the result only overflows for 3655 * ridiculously large PNG files. libpng checks and will refuse to handle 3656 * such data (the PNG is probably invalid.) 3657 * 3658 * Take great care over the type of 'row_stride'; libpng assumes that the 3659 * type is png_alloc_size_t, as returned by PNG_IMAGE_ROW_STRIDE. You can 3660 * use any type you like but libpng only checks for overflow when the type is 3661 * png_alloc_size_t. In particular for png_uint_32 on a 64-bit system you 3662 * must do your own overflow checking. Cast row_stride as (png_alloc_size_t) 3663 * to avoid this (check for overflow before the cast of course!) 3664 */ 3665 3666 #define PNG_IMAGE_SIZE(image)\ 3667 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image)) 3668 /* Return the size, in bytes, of the image in memory given just a png_image; 3669 * the row stride is the minimum stride required for the image. 3670 */ 3671 3672 #define PNG_IMAGE_COLORMAP_SIZE(image)\ 3673 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries) 3674 /* Return the size, in bytes, of the color-map of this image. If the image 3675 * format is not a color-map format this will return a size sufficient for 3676 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if 3677 * you don't want to allocate a color-map in this case. 3678 */ 3679 3680 /* PNG_IMAGE_FLAG_* 3681 * 3682 * Flags containing additional information about the image are held in the 3683 * 'flags' field of png_image. 3684 */ 3685 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01 3686 /* This indicates the the RGB values of the in-memory bitmap do not 3687 * correspond to the red, green and blue end-points defined by sRGB. 3688 */ 3689 3690 #define PNG_IMAGE_FLAG_FAST 0x02 3691 /* On write emphasise speed over compression; the resultant PNG file will be 3692 * larger but will be produced significantly faster, particular for large 3693 * images. Do not use this option for images which will be distributed, only 3694 * used it when producing intermediate files that will be read back in 3695 * repeatedly. For a typical 24-bit image the option will double the read 3696 * speed at the cost of increasing the image size by 25%, however for many 3697 * more compressible images the PNG file can be 10 times larger with only a 3698 * slight speed gain. 3699 */ 3700 3701 #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04 3702 /* On read if the image is a 16-bit per component image and there is no gAMA 3703 * or sRGB chunk assume that the components are sRGB encoded. Notice that 3704 * images output by the simplified API always have gamma information; setting 3705 * this flag only affects the interpretation of 16-bit images from an 3706 * external source. It is recommended that the application expose this flag 3707 * to the user; the user can normally easily recognize the difference between 3708 * linear and sRGB encoding. This flag has no effect on write - the data 3709 * passed to the write APIs must have the correct encoding (as defined 3710 * above.) 3711 * 3712 * If the flag is not set (the default) input 16-bit per component data is 3713 * assumed to be linear. 3714 * 3715 * NOTE: the flag can only be set after the png_image_begin_read_ call, 3716 * because that call initializes the 'flags' field. 3717 */ 3718 3719 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED 3720 /* READ APIs 3721 * --------- 3722 * 3723 * The png_image passed to the read APIs must have been initialized by setting 3724 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.) 3725 */ 3726 #ifdef PNG_STDIO_SUPPORTED 3727 PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image, 3728 const char *file_name)); 3729 /* The named file is opened for read and the image header is filled in 3730 * from the PNG header in the file. 3731 */ 3732 3733 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image, 3734 FILE* file)); 3735 /* The PNG header is read from the stdio FILE object. */ 3736 #endif /* STDIO */ 3737 3738 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image, 3739 png_const_voidp memory, size_t size)); 3740 /* The PNG header is read from the given memory buffer. */ 3741 3742 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image, 3743 png_const_colorp background, void *buffer, ptrdiff_t row_stride, 3744 void *colormap)); 3745 /* Finish reading the image into the supplied buffer and clean up the 3746 * png_image structure. 3747 * 3748 * row_stride is the step, in byte or 2-byte units as appropriate, 3749 * between adjacent rows. A positive stride indicates that the top-most row 3750 * is first in the buffer - the normal top-down arrangement. A negative 3751 * stride indicates that the bottom-most row is first in the buffer. 3752 * 3753 * background need only be supplied if an alpha channel must be removed from 3754 * a png_byte format and the removal is to be done by compositing on a solid 3755 * color; otherwise it may be NULL and any composition will be done directly 3756 * onto the buffer. The value is an sRGB color to use for the background, 3757 * for grayscale output the green channel is used. 3758 * 3759 * background must be supplied when an alpha channel must be removed from a 3760 * single byte color-mapped output format, in other words if: 3761 * 3762 * 1) The original format from png_image_begin_read_from_* had 3763 * PNG_FORMAT_FLAG_ALPHA set. 3764 * 2) The format set by the application does not. 3765 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and 3766 * PNG_FORMAT_FLAG_LINEAR *not* set. 3767 * 3768 * For linear output removing the alpha channel is always done by compositing 3769 * on black and background is ignored. 3770 * 3771 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must 3772 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE. 3773 * image->colormap_entries will be updated to the actual number of entries 3774 * written to the colormap; this may be less than the original value. 3775 */ 3776 3777 PNG_EXPORT(238, void, png_image_free, (png_imagep image)); 3778 /* Free any data allocated by libpng in image->opaque, setting the pointer to 3779 * NULL. May be called at any time after the structure is initialized. 3780 */ 3781 #endif /* SIMPLIFIED_READ */ 3782 3783 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED 3784 /* WRITE APIS 3785 * ---------- 3786 * For write you must initialize a png_image structure to describe the image to 3787 * be written. To do this use memset to set the whole structure to 0 then 3788 * initialize fields describing your image. 3789 * 3790 * version: must be set to PNG_IMAGE_VERSION 3791 * opaque: must be initialized to NULL 3792 * width: image width in pixels 3793 * height: image height in rows 3794 * format: the format of the data (image and color-map) you wish to write 3795 * flags: set to 0 unless one of the defined flags applies; set 3796 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB 3797 * values do not correspond to the colors in sRGB. 3798 * colormap_entries: set to the number of entries in the color-map (0 to 256) 3799 */ 3800 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED 3801 PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image, 3802 const char *file, int convert_to_8bit, const void *buffer, 3803 ptrdiff_t row_stride, const void *colormap)); 3804 /* Write the image to the named file. */ 3805 3806 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file, 3807 int convert_to_8_bit, const void *buffer, ptrdiff_t row_stride, 3808 const void *colormap)); 3809 /* Write the image to the given (FILE*). */ 3810 #endif /* SIMPLIFIED_WRITE_STDIO */ 3811 3812 /* With all write APIs if image is in one of the linear formats with 16-bit 3813 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG 3814 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear 3815 * encoded PNG file is written. 3816 * 3817 * With color-mapped data formats the colormap parameter point to a color-map 3818 * with at least image->colormap_entries encoded in the specified format. If 3819 * the format is linear the written PNG color-map will be converted to sRGB 3820 * regardless of the convert_to_8_bit flag. 3821 * 3822 * With all APIs row_stride is handled as in the read APIs - it is the spacing 3823 * from one row to the next in component sized units (1 or 2 bytes) and if 3824 * negative indicates a bottom-up row layout in the buffer. If row_stride is 3825 * zero, libpng will calculate it for you from the image width and number of 3826 * channels. 3827 * 3828 * Note that the write API does not support interlacing, sub-8-bit pixels or 3829 * most ancillary chunks. If you need to write text chunks (e.g. for copyright 3830 * notices) you need to use one of the other APIs. 3831 */ 3832 3833 PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory, 3834 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit, 3835 const void *buffer, ptrdiff_t row_stride, const void *colormap)); 3836 /* Write the image to the given memory buffer. The function both writes the 3837 * whole PNG data stream to *memory and updates *memory_bytes with the count 3838 * of bytes written. 3839 * 3840 * 'memory' may be NULL. In this case *memory_bytes is not read however on 3841 * success the number of bytes which would have been written will still be 3842 * stored in *memory_bytes. On failure *memory_bytes will contain 0. 3843 * 3844 * If 'memory' is not NULL it must point to memory[*memory_bytes] of 3845 * writeable memory. 3846 * 3847 * If the function returns success memory[*memory_bytes] (if 'memory' is not 3848 * NULL) contains the written PNG data. *memory_bytes will always be less 3849 * than or equal to the original value. 3850 * 3851 * If the function returns false and *memory_bytes was not changed an error 3852 * occured during write. If *memory_bytes was changed, or is not 0 if 3853 * 'memory' was NULL, the write would have succeeded but for the memory 3854 * buffer being too small. *memory_bytes contains the required number of 3855 * bytes and will be bigger that the original value. 3856 */ 3857 3858 #define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\ 3859 row_stride, colormap)\ 3860 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\ 3861 row_stride, colormap) 3862 /* Return the amount of memory in 'size' required to compress this image. 3863 * The png_image structure 'image' must be filled in as in the above 3864 * function and must not be changed before the actual write call, the buffer 3865 * and all other parameters must also be identical to that in the final 3866 * write call. The 'size' variable need not be initialized. 3867 * 3868 * NOTE: the macro returns true/false, if false is returned 'size' will be 3869 * set to zero and the write failed and probably will fail if tried again. 3870 */ 3871 3872 /* You can pre-allocate the buffer by making sure it is of sufficient size 3873 * regardless of the amount of compression achieved. The buffer size will 3874 * always be bigger than the original image and it will never be filled. The 3875 * following macros are provided to assist in allocating the buffer. 3876 */ 3877 #define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height) 3878 /* The number of uncompressed bytes in the PNG byte encoding of the image; 3879 * uncompressing the PNG IDAT data will give this number of bytes. 3880 */ 3881 #ifndef PNG_ZLIB_MAX_SIZE 3882 # define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U) 3883 /* An upper bound on the number of compressed bytes given 'b' uncompressed 3884 * bytes. This is based on deflateBounds() in zlib; different 3885 * implementations of zlib compression may conceivably produce more data so 3886 * if your zlib implementation is not zlib itself redefine this macro 3887 * appropriately. 3888 */ 3889 #endif 3890 3891 #define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\ 3892 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image)) 3893 /* An upper bound on the size of the data in the PNG IDAT chunks. */ 3894 3895 #define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\ 3896 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\ 3897 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\ 3898 12U+3U*(image).colormap_entries/*PLTE data*/+\ 3899 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\ 3900 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\ 3901 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size)) 3902 /* A helper for the following macro; if your compiler cannot handle the 3903 * following macro use this one with the result of 3904 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most 3905 * compilers should handle this just fine.) 3906 */ 3907 3908 #define PNG_IMAGE_PNG_SIZE_MAX(image)\ 3909 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image)) 3910 /* An upper bound on the total length of the PNG data stream for 'image'. 3911 * The result is of type png_alloc_size_t, on 32-bit systems this may 3912 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will 3913 * run out of buffer space but return a corrected size which should work. 3914 * 3915 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this 3916 * macro can because of the extra bytes used in the PNG byte encoding. You 3917 * need to avoid this macro if your image size approaches the limit of your 3918 * system memory; typically the maximum value of size_t. Use the above 3919 * function call instead. 3920 */ 3921 #endif /* SIMPLIFIED_WRITE */ 3922 /******************************************************************************* 3923 * END OF SIMPLIFIED API 3924 ******************************************************************************/ 3925 3926 /******************************************************************************* 3927 * Section 6: IMPLEMENTATION OPTIONS 3928 ******************************************************************************* 3929 * 3930 * Change of options used during read and/or write. 3931 * 3932 * A number of internal options can (but do not need to be) changed to 3933 * fine tune the implementation. These options control such things as the 3934 * precise settings for compression, the accuracy of arithmetic used internally 3935 * for image processing operations (gamma transformations) and, in some cases, 3936 * the specific implementations (hardware or software optimizations.) 3937 * 3938 * To avoid API proliferation there is a single general API (new in 1.7) to do 3939 * this. When a particular option is not supported by the build in libpng an 3940 * attempt to set it will return a failure code but will be totally ignored 3941 * unless the PNG_SF_ERROR flag is set (see below). 3942 */ 3943 PNG_EXPORT(249, png_int_32, png_setting, (png_structrp png_ptr, 3944 png_uint_32 setting, png_uint_32 parameter, png_int_32 value)); 3945 /* Alter setting 'setting' using the values of 'parameter' and 'value'. The 3946 * result is either one of the following failure codes or a setting/parameter 3947 * specific result code. 3948 * 3949 * The failure codes match the POSIX 1003.1 <errno.h> values (section 2.5, 3950 * error numbers) with a preceding PNG_. (png_uint_32)result gives a number 3951 * in the range 0x80000001U to 0x8000000fU. 3952 */ 3953 # define PNG_EBADF (-0x7fffffff) /* read/write error */ 3954 /* An attempt was made to apply a read setting to a write structure or 3955 * vice versa. 3956 */ 3957 # define PNG_EINVAL (-0x7ffffffe) /* invalid argument */ 3958 /* 'png_ptr' was NULL or 'parameter' or 'value' is invalid for the given 3959 * setting. 3960 */ 3961 # define PNG_EDOM (-0x7ffffffd) /* out of range */ 3962 /* Either 'parameter' or 'value' is out of range for the given setting 3963 * (only returned when paramter or value are used and are numeric; for 3964 * flag values PNG_EINVAL will be returned.) 3965 */ 3966 # define PNG_ENOSYS (-0x7ffffff1) /* unsupported setting/param */ 3967 /* The setting was not recognized; typically this means that libpng was 3968 * built without the appropriate support. 3969 */ 3970 # define PNG_UNSUPPORTED_SETTING PNG_ENOSYS 3971 /* For backware compatibility with earlier libpng versions and 3972 * 'png_set_option' return codes. 3973 */ 3974 # define PNG_UNSET (-0x7ffffff0) /* NOT an erro code: no previous setting */ 3975 /* The setting was not (previously) set. Returned when there is no built 3976 * in default for a setting. Normally this means that the default will 3977 * depend on other settings or the PNG itself. 3978 */ 3979 /* Results larger (more positive) than PNG_ENOSYS are success codes (even if 3980 * negative). The value is interpreted as follows (as defined by the 3981 * setting): 3982 * 3983 * 1) A signed 31-bit number in the range -0x7fffffef to +0x7fffffff 3984 * 2) An unsigned 31 bit number in the range 0U to 0x7fffffffU 3985 * 3) An unsigned 32 bit bit set/flag value in the range 0U to 0xfffffffU 3986 * but excluding values in the range 0x80000000U to 0x80000000FU 3987 * encoded as follows: 3988 * 3989 * if (v <= 0x7fffffffU) 3990 * v 3991 * else if (v > 0x8000000FU) 3992 * -(png_int_32)-v 3993 * 3994 * The result can be converted by to the original (png_uint_32) simply 3995 * by casting it as such. 3996 */ 3997 # define PNG_FAILED(result) ((result) <= PNG_ENOSYS) 3998 /* The setting did not take; this includes both errors making the setting 3999 * (e.g. parameter or value errors) and unsupported settings. Check the 4000 * result code itself for more information. 4001 */ 4002 # define PNG_OK(result) ((result) > PNG_ENOSYS) 4003 /* The setting succeeded; the result is a return code which depends on the 4004 * particular setting. (E.g. it might be a return code or it might be the 4005 * previous value.) 4006 */ 4007 4008 /* SETTING VALUES (generic) 4009 * 4010 * These are flag values that are added to the setting definitions below to 4011 * simplify processing inside libpng and self-document the setting behavior. 4012 * All these values have the prefix PNG_SF_ 4013 */ 4014 #define PNG_SF_ERROR (0x80000000U) 4015 /* If this is set on the 'setting' argument to png_setting and a failure code 4016 * would otherwise be returned call png_error instead. This is a convenience 4017 * for applications that do not want to check the result code. It is never 4018 * set by default. The error string is cryptic. 4019 */ 4020 #define PNG_SF_GET (0x40000000U) 4021 /* Do not set the setting. With most settings this just allows for the 4022 * presence of support for the setting to be checked at run time; if the 4023 * setting is not support PNG_ENOSYS will be returned. 4024 * 4025 * With some settings checking of the parameter or value may be done, but 4026 * there is no guarantee, so always supply valid parameter and value. 4027 * 4028 * With some settings the current setting is returned. This is typically 4029 * only done when the default setting is configurable and not even always 4030 * then. If the setting does this it will document the behavior. 4031 */ 4032 #define PNG_SF_READ (0x20000000U) 4033 /* The setting may be applied to a read png_struct. If this is not set and 4034 * an attempt is made to apply the setting to a read struct 4035 * PNG_EBADF will be returned. 4036 */ 4037 #define PNG_SF_WRITE (0x10000000U) 4038 /* The setting may be applied to a write png_struct. If this is not set 4039 * and an attempt is made to apply the setting to a write struct 4040 * PNG_EBADF will be returned. 4041 */ 4042 4043 /*********************************** WRITE ************************************/ 4044 /* WRITE COMPRESSION SUPPORT 4045 * 4046 * These settings are normally accessed using the macros that are defined above; 4047 * the function-like macros replace the API calls present in previous versions 4048 * of libpng. 4049 * 4050 * 'setting' is as follows, 'parameter' is a chunk name; png_IDAT for IDAT 4051 * compression, png_iCCP for iCCP chunk compression png_zTXt for zTZt *and* iTXt 4052 * text chunk compression. Other values must not be used; they will result in 4053 * PNG_ENOSYS at present but may alter compression of new chunks in the future. 4054 * 4055 * The value is the new compression setting. The result is is the old 4056 * compression setting or an error code. Compression settings are documented 4057 * in text above describing the function-like macros. PNG_UNSET is returned 4058 * when the setting was not previously set; in this case the default may vary 4059 * according to the actual data (e.g. length, PNG format). 4060 * 4061 * 0 is valid as a parameter if PNG_SF_GET is set, in that case the current or 4062 * last setting is returned. 4063 */ 4064 #define PNG_SW_COMPRESS_zlib_level (PNG_SF_WRITE + 0U) 4065 #define PNG_SW_COMPRESS_windowBits (PNG_SF_WRITE + 1U) 4066 #define PNG_SW_COMPRESS_memLevel (PNG_SF_WRITE + 2U) 4067 #define PNG_SW_COMPRESS_strategy (PNG_SF_WRITE + 3U) 4068 #define PNG_SW_COMPRESS_png_level (PNG_SF_WRITE + 4U) 4069 #define PNG_SW_COMPRESS_method (PNG_SF_WRITE + 5U) 4070 4071 /* WRITE IDAT size. 4072 * 4073 * The size of the IDAT chunks that are written (the last may be smaller). 4074 */ 4075 #define PNG_SW_IDAT_size (PNG_SF_WRITE + 6U) 4076 4077 /* WRITE FILTER CONTROL 4078 * 4079 * These settings are used by png_set_filter and png_set_row_buffers to control 4080 * the filters used during compression. The 'filters' setting has two arguments 4081 * however the first is the filter method (or type) and must be 0 for PNG. 4082 * Standards based on PNG may define additional values, as with other base file 4083 * characteristics such as the compression type, however the result would not be 4084 * a PNG. 4085 */ 4086 #define PNG_SW_COMPRESS_filters (PNG_SF_WRITE + 7U) 4087 #define PNG_SW_COMPRESS_row_buffers (PNG_SF_WRITE + 8U) 4088 4089 /* WRITE ROW FLUSH CONTROL 4090 * 4091 * This sets the number of rows between flush calls. '0' was used to indicate 4092 * no flushing (before the end). The maximum number of rows in a PNG is 4093 * actually greater than the maximum of a 31-bit integer for interlaced images, 4094 * however this doesn't matter much; the number of rows was always declared as 4095 * 'int', so it is still passed in the 'value' argument. 4096 */ 4097 #define PNG_SW_FLUSH (PNG_SF_WRITE + 9U) 4098 4099 /*********************************** READ *************************************/ 4100 /* The size of the buffer used while reading IDAT chunks and, potentially, other 4101 * compressed chunks. 4102 */ 4103 #define PNG_SR_COMPRESS_buffer_size (PNG_SF_READ + 1U) 4104 /* Read compressed data buffer size, in 'parameter'. The result is 0. */ 4105 4106 #define PNG_SR_GAMMA_threshold (PNG_SF_READ + 2U) 4107 #define png_set_gamma_threshold(png_ptr, threshold)\ 4108 (png_setting((png_ptr), PNG_SR_GAMMA_threshold, (threshold), 0)) 4109 /* SETTING: threshold below which gamma correction is not done, the default 4110 * (set when the library is built) is PNG_GAMMA_THRESHOLD_FIXED, the 4111 * 'parameter' is a png_fixed_point number, the difference from PNG_FP_1 4112 * above which gamma correction will be performed. 4113 * 4114 * The value '153' is sufficient to maintain 1% accuracy in 16-bit linear 4115 * calculations over a 655:1 range; over the maximum range possible with the 4116 * 16-bit linear representation. Reasonable values are: 4117 * 4118 * 0: always do gamma correction, even if the gamma values are 4119 * identical. The only point to this is to avoid a bug in the 4120 * optimized (no gamma correction) code path, or for testing. 4121 * 2: always do gamma correction if there is any significant 4122 * difference. Notice that '1' will result in gamma correction in 4123 * many cases when the screen gamma is the inverse of the encoding 4124 * gamma because of inaccuracies in the representation of gamma. 4125 * 153: do gamma correction if it is needed to maintain the accuracy of 4126 * 16-bit linear calculations at 1% or below. 4127 * 216: maintain 1% accuracy over a 100:1 dynamic range in 16-bit linear 4128 * calculations. This matches the widely accepted numbers for human 4129 * perception of differences within an image, however that doesn't 4130 * mean that such high accuracy is required to avoid artefacts; such 4131 * accuracy (such a low number) is only required if versions of the 4132 * same image with and without gamma correction are to be compared 4133 * visually. 4134 * 5000: this is the default from libpng 1.6 and earlier. Using this 4135 * produces changes in image contrast that are visible when suitable 4136 * images are compared side-by-side however they are not obvious and 4137 * it is inconceivable that a user would notice the change unless 4138 * the user was very familiar with the image and the viewing 4139 * environment. 4140 * 4141 * Values between 216 and 5000 produce varying very small changes in image 4142 * contrast. Values above 10,000 (10%) produce noticeable increase or 4143 * decrease in contrast which will probably change how the image is 4144 * perceived. There is an internal limit on the maximum value which is 4145 * currently 65%; PNG_EDOM will be returned for higher values. 4146 * 4147 * The result is the value that was set. 4148 */ 4149 #if 0 /*NYI*/ 4150 #define PNG_SR_GAMMA_accuracy /*NYI*/ 4151 /* SETTING: controls the accuracy of the gamma calculations when the results 4152 * are cached. The default is PNG_DEFAULT_GAMMA_ACCURACY. The number is 100 4153 * times the number of bits, 'b', used in the internal tables when the input 4154 * is linear, permitted values are 0..1600 however '0' causes the caching to 4155 * be skipped entirely (so gives maximum accuracy with no caching!) 4156 * 4157 * The accuracy in the linear domain for a value 'a' is: 4158 * 4159 * +/-(.5/2^a) 4160 * 4161 * so for the default-default of 665 this means the accuracy is +/-0.5% and 4162 * this ensures that almost-equal input values do not differ by more than 1% 4163 * in the output, meeting the accepted requirement for human vision. 4164 * 4165 * The default value has no effect on input narrower than 16 bits. For n-bit 4166 * input the total table size is ((n-v)+1)*(2^v), where 'v' is a/gamma and 4167 * 'gamma' is the gamma encoding of the input: 4168 * 4169 * n a gamma 'v' table size 4170 * 8 6.65 .45455 14.6 256 4171 * 16 6.65 .45455 14.6 65536 4172 * 16 6.65 1.0 6.65 1280 4173 * 16 6 1.0 6 704 4174 * 16 5 1.0 5 384 4175 */ 4176 #endif /*NYI*/ 4177 4178 #define PNG_SR_CRC_ACTION (PNG_SF_READ + 4U) 4179 /* 'parameter' is what to do with critical chunks, 'value' is what to do with 4180 * ancillary ones when the CRC does not match on read. 0 is returned. See 4181 * png_set_crc_action for more information. 4182 */ 4183 4184 /*********************************** OPTIONS **********************************/ 4185 /* png_set_option is implemented via png_setting to provide API compatibility 4186 * with releases prior to 1.7.0 4187 */ 4188 /* HARDWARE OPTIMIZATIONS 4189 * 4190 * Normally hardware capabilites, such as the Intel SSE instructions, are 4191 * detected at run time, however sometimes it may be impossible to do this in 4192 * user mode, in which case it is necessary to discover the capabilities in an 4193 * OS specific way. Such capabilities are listed here when libpng has support 4194 * for them and must be turned ON by the application if present. Check 4195 * pnglibconf.h for options appropriate to your hardware. 4196 * 4197 * In general 'PNG_EXTENSIONS' controls hardware optimizations; these are not 4198 * supported parts of libpng and, if there are problems with them, bugs should 4199 * be ported to the implementers. Depending on the configuration it may not be 4200 * possible to disable extensions at run time. 4201 */ 4202 #define PNG_SRW_OPTION (PNG_SF_READ+PNG_SF_WRITE + 0U) 4203 #ifdef PNG_SET_OPTION_SUPPORTED 4204 PNG_REMOVED(244, int, png_set_option, (png_structrp png_ptr, int option, 4205 int onoff), PNG_EMPTY) 4206 4207 #define png_set_option(p, opt, onoff)\ 4208 (png_setting((p), PNG_SRW_OPTION, (opt), (onoff))) 4209 /* Pre 1.7 API; in 1.7 the result values have changed numerically but not by 4210 * name. For backward API compatibility this setting only returns one error 4211 * code, PNG_ENOSYS and that only for option numbers out of range, otherwise 4212 * if the option isn't supported PNG_OPTION_UNSET (PNG_UNSET) is returned. 4213 */ 4214 #endif /* SET_OPTION */ 4215 #define PNG_OPTION_UNSET PNG_UNSET /* Unset - defaults to off */ 4216 #define PNG_OPTION_INVALID PNG_ENOSYS /* Option number out of range */ 4217 #define PNG_OPTION_OFF 0 4218 #define PNG_OPTION_ON 1 4219 4220 /* Specific options: */ 4221 #define PNG_EXTENSIONS 0 /* HARDWARE: switch extensions on or off */ 4222 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */ 4223 #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */ 4224 #define PNG_OPTION_NEXT 6 /* Next option - numbers are even */ 4225 4226 #define PNG_SRW_CHECK_FOR_INVALID_INDEX (PNG_SF_READ+PNG_SF_WRITE + 1U) 4227 /* Turn the palette index check on or off; see 4228 * png_set_check_for_invalid_index above. 4229 */ 4230 4231 #define PNG_SRW_ERROR_HANDLING (PNG_SF_READ+PNG_SF_WRITE + 2U) 4232 /* Change the action on issues that can be handled. */ 4233 4234 /******************************************************************************* 4235 * END OF HARDWARE OPTIONS 4236 ******************************************************************************/ 4237 4238 /* The last ordinal number (this is the *last* one already used; the next 4239 * one to use is one more than this.) Maintainer, remember to add an entry to 4240 * scripts/symbols.def as well. 4241 */ 4242 #ifdef PNG_EXPORT_LAST_ORDINAL 4243 PNG_EXPORT_LAST_ORDINAL(249); 4244 #endif 4245 4246 #ifdef __cplusplus 4247 } 4248 #endif 4249 4250 #endif /* PNG_VERSION_INFO_ONLY */ 4251 /* Do not put anything past this line */ 4252 #endif /* PNG_H */ 4253