1
2/* png.h - header file for PNG reference library
3 *
4 * libpng version 1.6.34, September 29, 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 1.6.34, September 29, 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 1.6.34, September 29, 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 * Mandar Sahastrabuddhe
41 * Google Inc.
42 * Vadim Barkov
43 *
44 * and with the following additions to the disclaimer:
45 *
46 * There is no warranty against interference with your enjoyment of the
47 * library or against infringement. There is no warranty that our
48 * efforts or the library will fulfill any of your particular purposes
49 * or needs. This library is provided with all faults, and the entire
50 * risk of satisfactory quality, performance, accuracy, and effort is with
51 * the user.
52 *
53 * Some files in the "contrib" directory and some configure-generated
54 * files that are distributed with libpng have other copyright owners and
55 * are released under other open source licenses.
56 *
57 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
58 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
59 * libpng-0.96, and are distributed according to the same disclaimer and
60 * license as libpng-0.96, with the following individuals added to the list
61 * of Contributing Authors:
62 *
63 * Tom Lane
64 * Glenn Randers-Pehrson
65 * Willem van Schaik
66 *
67 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
68 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
69 * and are distributed according to the same disclaimer and license as
70 * libpng-0.88, with the following individuals added to the list of
71 * Contributing Authors:
72 *
73 * John Bowler
74 * Kevin Bracey
75 * Sam Bushell
76 * Magnus Holmgren
77 * Greg Roelofs
78 * Tom Tanner
79 *
80 * Some files in the "scripts" directory have other copyright owners
81 * but are released under this license.
82 *
83 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
84 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
85 *
86 * For the purposes of this copyright and license, "Contributing Authors"
87 * is defined as the following set of individuals:
88 *
89 * Andreas Dilger
90 * Dave Martindale
91 * Guy Eric Schalnat
92 * Paul Schmidt
93 * Tim Wegner
94 *
95 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
96 * and Group 42, Inc. disclaim all warranties, expressed or implied,
97 * including, without limitation, the warranties of merchantability and of
98 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
99 * assume no liability for direct, indirect, incidental, special, exemplary,
100 * or consequential damages, which may result from the use of the PNG
101 * Reference Library, even if advised of the possibility of such damage.
102 *
103 * Permission is hereby granted to use, copy, modify, and distribute this
104 * source code, or portions hereof, for any purpose, without fee, subject
105 * to the following restrictions:
106 *
107 * 1. The origin of this source code must not be misrepresented.
108 *
109 * 2. Altered versions must be plainly marked as such and must not
110 * be misrepresented as being the original source.
111 *
112 * 3. This Copyright notice may not be removed or altered from any
113 * source or altered source distribution.
114 *
115 * The Contributing Authors and Group 42, Inc. specifically permit, without
116 * fee, and encourage the use of this source code as a component to
117 * supporting the PNG file format in commercial products. If you use this
118 * source code in a product, acknowledgment is not required but would be
119 * appreciated.
120 *
121 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
122 *
123 * TRADEMARK:
124 *
125 * The name "libpng" has not been registered by the Copyright owner
126 * as a trademark in any jurisdiction. However, because libpng has
127 * been distributed and maintained world-wide, continually since 1995,
128 * the Copyright owner claims "common-law trademark protection" in any
129 * jurisdiction where common-law trademark is recognized.
130 *
131 * OSI CERTIFICATION:
132 *
133 * Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
134 * a certification mark of the Open Source Initiative. OSI has not addressed
135 * the additional disclaimers inserted at version 1.0.7.
136 *
137 * EXPORT CONTROL:
138 *
139 * The Copyright owner believes that the Export Control Classification
140 * Number (ECCN) for libpng is EAR99, which means not subject to export
141 * controls or International Traffic in Arms Regulations (ITAR) because
142 * it is open source, publicly available software, that does not contain
143 * any encryption software. See the EAR, paragraphs 734.3(b)(3) and
144 * 734.7(b).
145 */
146
147/*
148 * A "png_get_copyright" function is available, for convenient use in "about"
149 * boxes and the like:
150 *
151 * printf("%s", png_get_copyright(NULL));
152 *
153 * Also, the PNG logo (in PNG format, of course) is supplied in the
154 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
155 */
156
157/*
158 * The contributing authors would like to thank all those who helped
159 * with testing, bug fixes, and patience. This wouldn't have been
160 * possible without all of you.
161 *
162 * Thanks to Frank J. T. Wojcik for helping with the documentation.
163 */
164
165/* Note about libpng version numbers:
166 *
167 * Due to various miscommunications, unforeseen code incompatibilities
168 * and occasional factors outside the authors' control, version numbering
169 * on the library has not always been consistent and straightforward.
170 * The following table summarizes matters since version 0.89c, which was
171 * the first widely used release:
172 *
173 * source png.h png.h shared-lib
174 * version string int version
175 * ------- ------ ----- ----------
176 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
177 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
178 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
179 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
180 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
181 * 0.97c 0.97 97 2.0.97
182 * 0.98 0.98 98 2.0.98
183 * 0.99 0.99 98 2.0.99
184 * 0.99a-m 0.99 99 2.0.99
185 * 1.00 1.00 100 2.1.0 [100 should be 10000]
186 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
187 * 1.0.1 png.h string is 10001 2.1.0
188 * 1.0.1a-e identical to the 10002 from here on, the shared library
189 * 1.0.2 source version) 10002 is 2.V where V is the source code
190 * 1.0.2a-b 10003 version, except as noted.
191 * 1.0.3 10003
192 * 1.0.3a-d 10004
193 * 1.0.4 10004
194 * 1.0.4a-f 10005
195 * 1.0.5 (+ 2 patches) 10005
196 * 1.0.5a-d 10006
197 * 1.0.5e-r 10100 (not source compatible)
198 * 1.0.5s-v 10006 (not binary compatible)
199 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
200 * 1.0.6d-f 10007 (still binary incompatible)
201 * 1.0.6g 10007
202 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
203 * 1.0.6i 10007 10.6i
204 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
205 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
206 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
207 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
208 * 1.0.7 1 10007 (still compatible)
209 * ...
210 * 1.0.19 10 10019 10.so.0.19[.0]
211 * ...
212 * 1.2.59 13 10257 12.so.0.59[.0]
213 * ...
214 * 1.5.30 15 10527 15.so.15.30[.0]
215 * ...
216 * 1.6.34 16 10633 16.so.16.34[.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 * September 29, 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 1.6.34 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 "1.6.34"
313#define PNG_HEADER_VERSION_STRING " libpng version 1.6.34 - September 29, 2017\n"
314
315#define PNG_LIBPNG_VER_SONUM 16
316#define PNG_LIBPNG_VER_DLLNUM 16
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 6
321#define PNG_LIBPNG_VER_RELEASE 34
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 0
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_STABLE
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 10634 /* 1.6.34 */
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/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
398#ifdef __cplusplus
399extern "C" {
400#endif /* __cplusplus */
401
402/* Version information for C files, stored in png.c. This had better match
403 * the version above.
404 */
405#define png_libpng_ver png_get_header_ver(NULL)
406
407/* This file is arranged in several sections:
408 *
409 * 1. [omitted]
410 * 2. Any configuration options that can be specified by for the application
411 * code when it is built. (Build time configuration is in pnglibconf.h)
412 * 3. Type definitions (base types are defined in pngconf.h), structure
413 * definitions.
414 * 4. Exported library functions.
415 * 5. Simplified API.
416 * 6. Implementation options.
417 *
418 * The library source code has additional files (principally pngpriv.h) that
419 * allow configuration of the library.
420 */
421
422/* Section 1: [omitted] */
423
424/* Section 2: run time configuration
425 * See pnglibconf.h for build time configuration
426 *
427 * Run time configuration allows the application to choose between
428 * implementations of certain arithmetic APIs. The default is set
429 * at build time and recorded in pnglibconf.h, but it is safe to
430 * override these (and only these) settings. Note that this won't
431 * change what the library does, only application code, and the
432 * settings can (and probably should) be made on a per-file basis
433 * by setting the #defines before including png.h
434 *
435 * Use macros to read integers from PNG data or use the exported
436 * functions?
437 * PNG_USE_READ_MACROS: use the macros (see below) Note that
438 * the macros evaluate their argument multiple times.
439 * PNG_NO_USE_READ_MACROS: call the relevant library function.
440 *
441 * Use the alternative algorithm for compositing alpha samples that
442 * does not use division?
443 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
444 * algorithm.
445 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
446 *
447 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
448 * false?
449 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
450 * APIs to png_warning.
451 * Otherwise the calls are mapped to png_error.
452 */
453
454/* Section 3: type definitions, including structures and compile time
455 * constants.
456 * See pngconf.h for base types that vary by machine/system
457 */
458
459/* This triggers a compiler error in png.c, if png.c and png.h
460 * do not agree upon the version number.
461 */
462typedef char* png_libpng_version_1_6_34;
463
464/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
465 *
466 * png_struct is the cache of information used while reading or writing a single
467 * PNG file. One of these is always required, although the simplified API
468 * (below) hides the creation and destruction of it.
469 */
470typedef struct png_struct_def png_struct;
471typedef const png_struct * png_const_structp;
472typedef png_struct * png_structp;
473typedef png_struct * * png_structpp;
474
475/* png_info contains information read from or to be written to a PNG file. One
476 * or more of these must exist while reading or creating a PNG file. The
477 * information is not used by libpng during read but is used to control what
478 * gets written when a PNG file is created. "png_get_" function calls read
479 * information during read and "png_set_" functions calls write information
480 * when creating a PNG.
481 * been moved into a separate header file that is not accessible to
482 * applications. Read libpng-manual.txt or libpng.3 for more info.
483 */
484typedef struct png_info_def png_info;
485typedef png_info * png_infop;
486typedef const png_info * png_const_infop;
487typedef png_info * * png_infopp;
488
489/* Types with names ending 'p' are pointer types. The corresponding types with
490 * names ending 'rp' are identical pointer types except that the pointer is
491 * marked 'restrict', which means that it is the only pointer to the object
492 * passed to the function. Applications should not use the 'restrict' types;
493 * it is always valid to pass 'p' to a pointer with a function argument of the
494 * corresponding 'rp' type. Different compilers have different rules with
495 * regard to type matching in the presence of 'restrict'. For backward
496 * compatibility libpng callbacks never have 'restrict' in their parameters and,
497 * consequentially, writing portable application code is extremely difficult if
498 * an attempt is made to use 'restrict'.
499 */
500typedef png_struct * PNG_RESTRICT png_structrp;
501typedef const png_struct * PNG_RESTRICT png_const_structrp;
502typedef png_info * PNG_RESTRICT png_inforp;
503typedef const png_info * PNG_RESTRICT png_const_inforp;
504
505/* Three color definitions. The order of the red, green, and blue, (and the
506 * exact size) is not important, although the size of the fields need to
507 * be png_byte or png_uint_16 (as defined below).
508 */
509typedef struct png_color_struct
510{
511 png_byte red;
512 png_byte green;
513 png_byte blue;
514} png_color;
515typedef png_color * png_colorp;
516typedef const png_color * png_const_colorp;
517typedef png_color * * png_colorpp;
518
519typedef struct png_color_16_struct
520{
521 png_byte index; /* used for palette files */
522 png_uint_16 red; /* for use in red green blue files */
523 png_uint_16 green;
524 png_uint_16 blue;
525 png_uint_16 gray; /* for use in grayscale files */
526} png_color_16;
527typedef png_color_16 * png_color_16p;
528typedef const png_color_16 * png_const_color_16p;
529typedef png_color_16 * * png_color_16pp;
530
531typedef struct png_color_8_struct
532{
533 png_byte red; /* for use in red green blue files */
534 png_byte green;
535 png_byte blue;
536 png_byte gray; /* for use in grayscale files */
537 png_byte alpha; /* for alpha channel files */
538} png_color_8;
539typedef png_color_8 * png_color_8p;
540typedef const png_color_8 * png_const_color_8p;
541typedef png_color_8 * * png_color_8pp;
542
543/*
544 * The following two structures are used for the in-core representation
545 * of sPLT chunks.
546 */
547typedef struct png_sPLT_entry_struct
548{
549 png_uint_16 red;
550 png_uint_16 green;
551 png_uint_16 blue;
552 png_uint_16 alpha;
553 png_uint_16 frequency;
554} png_sPLT_entry;
555typedef png_sPLT_entry * png_sPLT_entryp;
556typedef const png_sPLT_entry * png_const_sPLT_entryp;
557typedef png_sPLT_entry * * png_sPLT_entrypp;
558
559/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
560 * occupy the LSB of their respective members, and the MSB of each member
561 * is zero-filled. The frequency member always occupies the full 16 bits.
562 */
563
564typedef struct png_sPLT_struct
565{
566 png_charp name; /* palette name */
567 png_byte depth; /* depth of palette samples */
568 png_sPLT_entryp entries; /* palette entries */
569 png_int_32 nentries; /* number of palette entries */
570} png_sPLT_t;
571typedef png_sPLT_t * png_sPLT_tp;
572typedef const png_sPLT_t * png_const_sPLT_tp;
573typedef png_sPLT_t * * png_sPLT_tpp;
574
575#ifdef PNG_TEXT_SUPPORTED
576/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
577 * and whether that contents is compressed or not. The "key" field
578 * points to a regular zero-terminated C string. The "text" fields can be a
579 * regular C string, an empty string, or a NULL pointer.
580 * However, the structure returned by png_get_text() will always contain
581 * the "text" field as a regular zero-terminated C string (possibly
582 * empty), never a NULL pointer, so it can be safely used in printf() and
583 * other string-handling functions. Note that the "itxt_length", "lang", and
584 * "lang_key" members of the structure only exist when the library is built
585 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
586 * default without iTXt support. Also note that when iTXt *is* supported,
587 * the "lang" and "lang_key" fields contain NULL pointers when the
588 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
589 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
590 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
591 * which is always 0 or 1, or its "compression method" which is always 0.
592 */
593typedef struct png_text_struct
594{
595 int compression; /* compression value:
596 -1: tEXt, none
597 0: zTXt, deflate
598 1: iTXt, none
599 2: iTXt, deflate */
600 png_charp key; /* keyword, 1-79 character description of "text" */
601 png_charp text; /* comment, may be an empty string (ie "")
602 or a NULL pointer */
603 png_size_t text_length; /* length of the text string */
604 png_size_t itxt_length; /* length of the itxt string */
605 png_charp lang; /* language code, 0-79 characters
606 or a NULL pointer */
607 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
608 chars or a NULL pointer */
609} png_text;
610typedef png_text * png_textp;
611typedef const png_text * png_const_textp;
612typedef png_text * * png_textpp;
613#endif
614
615/* Supported compression types for text in PNG files (tEXt, and zTXt).
616 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
617#define PNG_TEXT_COMPRESSION_NONE_WR -3
618#define PNG_TEXT_COMPRESSION_zTXt_WR -2
619#define PNG_TEXT_COMPRESSION_NONE -1
620#define PNG_TEXT_COMPRESSION_zTXt 0
621#define PNG_ITXT_COMPRESSION_NONE 1
622#define PNG_ITXT_COMPRESSION_zTXt 2
623#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
624
625/* png_time is a way to hold the time in an machine independent way.
626 * Two conversions are provided, both from time_t and struct tm. There
627 * is no portable way to convert to either of these structures, as far
628 * as I know. If you know of a portable way, send it to me. As a side
629 * note - PNG has always been Year 2000 compliant!
630 */
631typedef struct png_time_struct
632{
633 png_uint_16 year; /* full year, as in, 1995 */
634 png_byte month; /* month of year, 1 - 12 */
635 png_byte day; /* day of month, 1 - 31 */
636 png_byte hour; /* hour of day, 0 - 23 */
637 png_byte minute; /* minute of hour, 0 - 59 */
638 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
639} png_time;
640typedef png_time * png_timep;
641typedef const png_time * png_const_timep;
642typedef png_time * * png_timepp;
643
644#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
645 defined(PNG_USER_CHUNKS_SUPPORTED)
646/* png_unknown_chunk is a structure to hold queued chunks for which there is
647 * no specific support. The idea is that we can use this to queue
648 * up private chunks for output even though the library doesn't actually
649 * know about their semantics.
650 *
651 * The data in the structure is set by libpng on read and used on write.
652 */
653typedef struct png_unknown_chunk_t
654{
655 png_byte name[5]; /* Textual chunk name with '\0' terminator */
656 png_byte *data; /* Data, should not be modified on read! */
657 png_size_t size;
658
659 /* On write 'location' must be set using the flag values listed below.
660 * Notice that on read it is set by libpng however the values stored have
661 * more bits set than are listed below. Always treat the value as a
662 * bitmask. On write set only one bit - setting multiple bits may cause the
663 * chunk to be written in multiple places.
664 */
665 png_byte location; /* mode of operation at read time */
666}
667png_unknown_chunk;
668
669typedef png_unknown_chunk * png_unknown_chunkp;
670typedef const png_unknown_chunk * png_const_unknown_chunkp;
671typedef png_unknown_chunk * * png_unknown_chunkpp;
672#endif
673
674/* Flag values for the unknown chunk location byte. */
675#define PNG_HAVE_IHDR 0x01
676#define PNG_HAVE_PLTE 0x02
677#define PNG_AFTER_IDAT 0x08
678
679/* Maximum positive integer used in PNG is (2^31)-1 */
680#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
681#define PNG_UINT_32_MAX ((png_uint_32)(-1))
682#define PNG_SIZE_MAX ((png_size_t)(-1))
683
684/* These are constants for fixed point values encoded in the
685 * PNG specification manner (x100000)
686 */
687#define PNG_FP_1 100000
688#define PNG_FP_HALF 50000
689#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
690#define PNG_FP_MIN (-PNG_FP_MAX)
691
692/* These describe the color_type field in png_info. */
693/* color type masks */
694#define PNG_COLOR_MASK_PALETTE 1
695#define PNG_COLOR_MASK_COLOR 2
696#define PNG_COLOR_MASK_ALPHA 4
697
698/* color types. Note that not all combinations are legal */
699#define PNG_COLOR_TYPE_GRAY 0
700#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
701#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
702#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
703#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
704/* aliases */
705#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
706#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
707
708/* This is for compression type. PNG 1.0-1.2 only define the single type. */
709#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
710#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
711
712/* This is for filter type. PNG 1.0-1.2 only define the single type. */
713#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
714#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
715#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
716
717/* These are for the interlacing type. These values should NOT be changed. */
718#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
719#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
720#define PNG_INTERLACE_LAST 2 /* Not a valid value */
721
722/* These are for the oFFs chunk. These values should NOT be changed. */
723#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
724#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
725#define PNG_OFFSET_LAST 2 /* Not a valid value */
726
727/* These are for the pCAL chunk. These values should NOT be changed. */
728#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
729#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
730#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
731#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
732#define PNG_EQUATION_LAST 4 /* Not a valid value */
733
734/* These are for the sCAL chunk. These values should NOT be changed. */
735#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
736#define PNG_SCALE_METER 1 /* meters per pixel */
737#define PNG_SCALE_RADIAN 2 /* radians per pixel */
738#define PNG_SCALE_LAST 3 /* Not a valid value */
739
740/* These are for the pHYs chunk. These values should NOT be changed. */
741#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
742#define PNG_RESOLUTION_METER 1 /* pixels/meter */
743#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
744
745/* These are for the sRGB chunk. These values should NOT be changed. */
746#define PNG_sRGB_INTENT_PERCEPTUAL 0
747#define PNG_sRGB_INTENT_RELATIVE 1
748#define PNG_sRGB_INTENT_SATURATION 2
749#define PNG_sRGB_INTENT_ABSOLUTE 3
750#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
751
752/* This is for text chunks */
753#define PNG_KEYWORD_MAX_LENGTH 79
754
755/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
756#define PNG_MAX_PALETTE_LENGTH 256
757
758/* These determine if an ancillary chunk's data has been successfully read
759 * from the PNG header, or if the application has filled in the corresponding
760 * data in the info_struct to be written into the output file. The values
761 * of the PNG_INFO_<chunk> defines should NOT be changed.
762 */
763#define PNG_INFO_gAMA 0x0001U
764#define PNG_INFO_sBIT 0x0002U
765#define PNG_INFO_cHRM 0x0004U
766#define PNG_INFO_PLTE 0x0008U
767#define PNG_INFO_tRNS 0x0010U
768#define PNG_INFO_bKGD 0x0020U
769#define PNG_INFO_hIST 0x0040U
770#define PNG_INFO_pHYs 0x0080U
771#define PNG_INFO_oFFs 0x0100U
772#define PNG_INFO_tIME 0x0200U
773#define PNG_INFO_pCAL 0x0400U
774#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
775#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
776#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
777#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
778#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
779#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
780
781/* This is used for the transformation routines, as some of them
782 * change these values for the row. It also should enable using
783 * the routines for other purposes.
784 */
785typedef struct png_row_info_struct
786{
787 png_uint_32 width; /* width of row */
788 png_size_t rowbytes; /* number of bytes in row */
789 png_byte color_type; /* color type of row */
790 png_byte bit_depth; /* bit depth of row */
791 png_byte channels; /* number of channels (1, 2, 3, or 4) */
792 png_byte pixel_depth; /* bits per pixel (depth * channels) */
793} png_row_info;
794
795typedef png_row_info * png_row_infop;
796typedef png_row_info * * png_row_infopp;
797
798/* These are the function types for the I/O functions and for the functions
799 * that allow the user to override the default I/O functions with his or her
800 * own. The png_error_ptr type should match that of user-supplied warning
801 * and error functions, while the png_rw_ptr type should match that of the
802 * user read/write data functions. Note that the 'write' function must not
803 * modify the buffer it is passed. The 'read' function, on the other hand, is
804 * expected to return the read data in the buffer.
805 */
806typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
807typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
808typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
809typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
810 int));
811typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
812 int));
813
814#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
815typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
816typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
817
818/* The following callback receives png_uint_32 row_number, int pass for the
819 * png_bytep data of the row. When transforming an interlaced image the
820 * row number is the row number within the sub-image of the interlace pass, so
821 * the value will increase to the height of the sub-image (not the full image)
822 * then reset to 0 for the next pass.
823 *
824 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
825 * find the output pixel (x,y) given an interlaced sub-image pixel
826 * (row,col,pass). (See below for these macros.)
827 */
828typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
829 png_uint_32, int));
830#endif
831
832#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
833 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
834typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
835 png_bytep));
836#endif
837
838#ifdef PNG_USER_CHUNKS_SUPPORTED
839typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
840 png_unknown_chunkp));
841#endif
842#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
843/* not used anywhere */
844/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
845#endif
846
847#ifdef PNG_SETJMP_SUPPORTED
848/* This must match the function definition in <setjmp.h>, and the application
849 * must include this before png.h to obtain the definition of jmp_buf. The
850 * function is required to be PNG_NORETURN, but this is not checked. If the
851 * function does return the application will crash via an abort() or similar
852 * system level call.
853 *
854 * If you get a warning here while building the library you may need to make
855 * changes to ensure that pnglibconf.h records the calling convention used by
856 * your compiler. This may be very difficult - try using a different compiler
857 * to build the library!
858 */
859PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
860#endif
861
862/* Transform masks for the high-level interface */
863#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
864#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
865#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
866#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
867#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
868#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
869#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
870#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
871#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
872#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
873#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
874#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
875#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
876/* Added to libpng-1.2.34 */
877#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
878#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
879/* Added to libpng-1.4.0 */
880#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
881/* Added to libpng-1.5.4 */
882#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
883#if INT_MAX >= 0x8000 /* else this might break */
884#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
885#endif
886
887/* Flags for MNG supported features */
888#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
889#define PNG_FLAG_MNG_FILTER_64 0x04
890#define PNG_ALL_MNG_FEATURES 0x05
891
892/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
893 * this allowed the zlib default functions to be used on Windows
894 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
895 * ignores the first argument) should be completely compatible with the
896 * following.
897 */
898typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
899 png_alloc_size_t));
900typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
901
902/* Section 4: exported functions
903 * Here are the function definitions most commonly used. This is not
904 * the place to find out how to use libpng. See libpng-manual.txt for the
905 * full explanation, see example.c for the summary. This just provides
906 * a simple one line description of the use of each function.
907 *
908 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
909 * pngconf.h and in the *.dfn files in the scripts directory.
910 *
911 * PNG_EXPORT(ordinal, type, name, (args));
912 *
913 * ordinal: ordinal that is used while building
914 * *.def files. The ordinal value is only
915 * relevant when preprocessing png.h with
916 * the *.dfn files for building symbol table
917 * entries, and are removed by pngconf.h.
918 * type: return type of the function
919 * name: function name
920 * args: function arguments, with types
921 *
922 * When we wish to append attributes to a function prototype we use
923 * the PNG_EXPORTA() macro instead.
924 *
925 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
926 *
927 * ordinal, type, name, and args: same as in PNG_EXPORT().
928 * attributes: function attributes
929 */
930
931/* Returns the version number of the library */
932PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
933
934/* Tell lib we have already handled the first <num_bytes> magic bytes.
935 * Handling more than 8 bytes from the beginning of the file is an error.
936 */
937PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
938
939/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
940 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
941 * signature, and non-zero otherwise. Having num_to_check == 0 or
942 * start > 7 will always fail (ie return non-zero).
943 */
944PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
945 png_size_t num_to_check));
946
947/* Simple signature checking function. This is the same as calling
948 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
949 */
950#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
951
952/* Allocate and initialize png_ptr struct for reading, and any other memory. */
953PNG_EXPORTA(4, png_structp, png_create_read_struct,
954 (png_const_charp user_png_ver, png_voidp error_ptr,
955 png_error_ptr error_fn, png_error_ptr warn_fn),
956 PNG_ALLOCATED);
957
958/* Allocate and initialize png_ptr struct for writing, and any other memory */
959PNG_EXPORTA(5, png_structp, png_create_write_struct,
960 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
961 png_error_ptr warn_fn),
962 PNG_ALLOCATED);
963
964PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
965 (png_const_structrp png_ptr));
966
967PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
968 png_size_t size));
969
970/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
971 * match up.
972 */
973#ifdef PNG_SETJMP_SUPPORTED
974/* This function returns the jmp_buf built in to *png_ptr. It must be
975 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
976 * unless the default error function is overridden in which case NULL is
977 * acceptable. The size of the jmp_buf is checked against the actual size
978 * allocated by the library - the call will return NULL on a mismatch
979 * indicating an ABI mismatch.
980 */
981PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
982 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
983# define png_jmpbuf(png_ptr) \
984 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
985#else
986# define png_jmpbuf(png_ptr) \
987 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
988#endif
989/* This function should be used by libpng applications in place of
990 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
991 * will use it; otherwise it will call PNG_ABORT(). This function was
992 * added in libpng-1.5.0.
993 */
994PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
995 PNG_NORETURN);
996
997#ifdef PNG_READ_SUPPORTED
998/* Reset the compression stream */
999PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
1000#endif
1001
1002/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1003#ifdef PNG_USER_MEM_SUPPORTED
1004PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1005 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1006 png_error_ptr warn_fn,
1007 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1008 PNG_ALLOCATED);
1009PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1010 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1011 png_error_ptr warn_fn,
1012 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1013 PNG_ALLOCATED);
1014#endif
1015
1016/* Write the PNG file signature. */
1017PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
1018
1019/* Write a PNG chunk - size, type, (optional) data, CRC. */
1020PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
1021 chunk_name, png_const_bytep data, png_size_t length));
1022
1023/* Write the start of a PNG chunk - length and chunk name. */
1024PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1025 png_const_bytep chunk_name, png_uint_32 length));
1026
1027/* Write the data of a PNG chunk started with png_write_chunk_start(). */
1028PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1029 png_const_bytep data, png_size_t length));
1030
1031/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1032PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1033
1034/* Allocate and initialize the info structure */
1035PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1036 PNG_ALLOCATED);
1037
1038/* DEPRECATED: this function allowed init structures to be created using the
1039 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1040 * the API will be removed in the future.
1041 */
1042PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1043 png_size_t png_info_struct_size), PNG_DEPRECATED);
1044
1045/* Writes all the PNG information before the image. */
1046PNG_EXPORT(20, void, png_write_info_before_PLTE,
1047 (png_structrp png_ptr, png_const_inforp info_ptr));
1048PNG_EXPORT(21, void, png_write_info,
1049 (png_structrp png_ptr, png_const_inforp info_ptr));
1050
1051#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1052/* Read the information before the actual image data. */
1053PNG_EXPORT(22, void, png_read_info,
1054 (png_structrp png_ptr, png_inforp info_ptr));
1055#endif
1056
1057#ifdef PNG_TIME_RFC1123_SUPPORTED
1058 /* Convert to a US string format: there is no localization support in this
1059 * routine. The original implementation used a 29 character buffer in
1060 * png_struct, this will be removed in future versions.
1061 */
1062#if PNG_LIBPNG_VER < 10700
1063/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1064PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1065 png_const_timep ptime),PNG_DEPRECATED);
1066#endif
1067PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1068 png_const_timep ptime));
1069#endif
1070
1071#ifdef PNG_CONVERT_tIME_SUPPORTED
1072/* Convert from a struct tm to png_time */
1073PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1074 const struct tm * ttime));
1075
1076/* Convert from time_t to png_time. Uses gmtime() */
1077PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1078#endif /* CONVERT_tIME */
1079
1080#ifdef PNG_READ_EXPAND_SUPPORTED
1081/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1082PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1083PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1084PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1085PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1086#endif
1087
1088#ifdef PNG_READ_EXPAND_16_SUPPORTED
1089/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1090 * of a tRNS chunk if present.
1091 */
1092PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1093#endif
1094
1095#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1096/* Use blue, green, red order for pixels. */
1097PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1098#endif
1099
1100#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1101/* Expand the grayscale to 24-bit RGB if necessary. */
1102PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1103#endif
1104
1105#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1106/* Reduce RGB to grayscale. */
1107#define PNG_ERROR_ACTION_NONE 1
1108#define PNG_ERROR_ACTION_WARN 2
1109#define PNG_ERROR_ACTION_ERROR 3
1110#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1111
1112PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1113 int error_action, double red, double green))
1114PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1115 int error_action, png_fixed_point red, png_fixed_point green))
1116
1117PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1118 png_ptr));
1119#endif
1120
1121#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1122PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1123 png_colorp palette));
1124#endif
1125
1126#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1127/* How the alpha channel is interpreted - this affects how the color channels
1128 * of a PNG file are returned to the calling application when an alpha channel,
1129 * or a tRNS chunk in a palette file, is present.
1130 *
1131 * This has no effect on the way pixels are written into a PNG output
1132 * datastream. The color samples in a PNG datastream are never premultiplied
1133 * with the alpha samples.
1134 *
1135 * The default is to return data according to the PNG specification: the alpha
1136 * channel is a linear measure of the contribution of the pixel to the
1137 * corresponding composited pixel, and the color channels are unassociated
1138 * (not premultiplied). The gamma encoded color channels must be scaled
1139 * according to the contribution and to do this it is necessary to undo
1140 * the encoding, scale the color values, perform the composition and reencode
1141 * the values. This is the 'PNG' mode.
1142 *
1143 * The alternative is to 'associate' the alpha with the color information by
1144 * storing color channel values that have been scaled by the alpha.
1145 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1146 * (the latter being the two common names for associated alpha color channels).
1147 *
1148 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1149 * value is equal to the maximum value.
1150 *
1151 * The final choice is to gamma encode the alpha channel as well. This is
1152 * broken because, in practice, no implementation that uses this choice
1153 * correctly undoes the encoding before handling alpha composition. Use this
1154 * choice only if other serious errors in the software or hardware you use
1155 * mandate it; the typical serious error is for dark halos to appear around
1156 * opaque areas of the composited PNG image because of arithmetic overflow.
1157 *
1158 * The API function png_set_alpha_mode specifies which of these choices to use
1159 * with an enumerated 'mode' value and the gamma of the required output:
1160 */
1161#define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1162#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1163#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1164#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1165#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1166#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1167
1168PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1169 double output_gamma))
1170PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1171 int mode, png_fixed_point output_gamma))
1172#endif
1173
1174#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1175/* The output_gamma value is a screen gamma in libpng terminology: it expresses
1176 * how to decode the output values, not how they are encoded.
1177 */
1178#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1179#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1180#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1181#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1182#endif
1183
1184/* The following are examples of calls to png_set_alpha_mode to achieve the
1185 * required overall gamma correction and, where necessary, alpha
1186 * premultiplication.
1187 *
1188 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1189 * This is the default libpng handling of the alpha channel - it is not
1190 * pre-multiplied into the color components. In addition the call states
1191 * that the output is for a sRGB system and causes all PNG files without gAMA
1192 * chunks to be assumed to be encoded using sRGB.
1193 *
1194 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1195 * In this case the output is assumed to be something like an sRGB conformant
1196 * display preceeded by a power-law lookup table of power 1.45. This is how
1197 * early Mac systems behaved.
1198 *
1199 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1200 * This is the classic Jim Blinn approach and will work in academic
1201 * environments where everything is done by the book. It has the shortcoming
1202 * of assuming that input PNG data with no gamma information is linear - this
1203 * is unlikely to be correct unless the PNG files where generated locally.
1204 * Most of the time the output precision will be so low as to show
1205 * significant banding in dark areas of the image.
1206 *
1207 * png_set_expand_16(pp);
1208 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1209 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1210 * are assumed to have the sRGB encoding if not marked with a gamma value and
1211 * the output is always 16 bits per component. This permits accurate scaling
1212 * and processing of the data. If you know that your input PNG files were
1213 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1214 * correct value for your system.
1215 *
1216 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1217 * If you just need to composite the PNG image onto an existing background
1218 * and if you control the code that does this you can use the optimization
1219 * setting. In this case you just copy completely opaque pixels to the
1220 * output. For pixels that are not completely transparent (you just skip
1221 * those) you do the composition math using png_composite or png_composite_16
1222 * below then encode the resultant 8-bit or 16-bit values to match the output
1223 * encoding.
1224 *
1225 * Other cases
1226 * If neither the PNG nor the standard linear encoding work for you because
1227 * of the software or hardware you use then you have a big problem. The PNG
1228 * case will probably result in halos around the image. The linear encoding
1229 * will probably result in a washed out, too bright, image (it's actually too
1230 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1231 * substantially reduce the halos. Alternatively try:
1232 *
1233 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1234 * This option will also reduce the halos, but there will be slight dark
1235 * halos round the opaque parts of the image where the background is light.
1236 * In the OPTIMIZED mode the halos will be light halos where the background
1237 * is dark. Take your pick - the halos are unavoidable unless you can get
1238 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1239 * faster.)
1240 *
1241 * When the default gamma of PNG files doesn't match the output gamma.
1242 * If you have PNG files with no gamma information png_set_alpha_mode allows
1243 * you to provide a default gamma, but it also sets the ouput gamma to the
1244 * matching value. If you know your PNG files have a gamma that doesn't
1245 * match the output you can take advantage of the fact that
1246 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1247 * default if it is not already set:
1248 *
1249 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1250 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1251 * The first call sets both the default and the output gamma values, the
1252 * second call overrides the output gamma without changing the default. This
1253 * is easier than achieving the same effect with png_set_gamma. You must use
1254 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1255 * fire if more than one call to png_set_alpha_mode and png_set_background is
1256 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1257 * are ignored.
1258 */
1259
1260#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1261PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1262#endif
1263
1264#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1265 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1266PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1267#endif
1268
1269#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1270 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1271PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1272#endif
1273
1274#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1275/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1276PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1277 int flags));
1278/* The values of the PNG_FILLER_ defines should NOT be changed */
1279# define PNG_FILLER_BEFORE 0
1280# define PNG_FILLER_AFTER 1
1281/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1282PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1283 png_uint_32 filler, int flags));
1284#endif /* READ_FILLER || WRITE_FILLER */
1285
1286#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1287/* Swap bytes in 16-bit depth files. */
1288PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1289#endif
1290
1291#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1292/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1293PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1294#endif
1295
1296#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1297 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1298/* Swap packing order of pixels in bytes. */
1299PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1300#endif
1301
1302#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1303/* Converts files to legal bit depths. */
1304PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1305 true_bits));
1306#endif
1307
1308#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1309 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1310/* Have the code handle the interlacing. Returns the number of passes.
1311 * MUST be called before png_read_update_info or png_start_read_image,
1312 * otherwise it will not have the desired effect. Note that it is still
1313 * necessary to call png_read_row or png_read_rows png_get_image_height
1314 * times for each pass.
1315*/
1316PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1317#endif
1318
1319#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1320/* Invert monochrome files */
1321PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1322#endif
1323
1324#ifdef PNG_READ_BACKGROUND_SUPPORTED
1325/* Handle alpha and tRNS by replacing with a background color. Prior to
1326 * libpng-1.5.4 this API must not be called before the PNG file header has been
1327 * read. Doing so will result in unexpected behavior and possible warnings or
1328 * errors if the PNG file contains a bKGD chunk.
1329 */
1330PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1331 png_const_color_16p background_color, int background_gamma_code,
1332 int need_expand, double background_gamma))
1333PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1334 png_const_color_16p background_color, int background_gamma_code,
1335 int need_expand, png_fixed_point background_gamma))
1336#endif
1337#ifdef PNG_READ_BACKGROUND_SUPPORTED
1338# define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1339# define PNG_BACKGROUND_GAMMA_SCREEN 1
1340# define PNG_BACKGROUND_GAMMA_FILE 2
1341# define PNG_BACKGROUND_GAMMA_UNIQUE 3
1342#endif
1343
1344#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1345/* Scale a 16-bit depth file down to 8-bit, accurately. */
1346PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1347#endif
1348
1349#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1350#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
1351/* Strip the second byte of information from a 16-bit depth file. */
1352PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1353#endif
1354
1355#ifdef PNG_READ_QUANTIZE_SUPPORTED
1356/* Turn on quantizing, and reduce the palette to the number of colors
1357 * available.
1358 */
1359PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1360 png_colorp palette, int num_palette, int maximum_colors,
1361 png_const_uint_16p histogram, int full_quantize));
1362#endif
1363
1364#ifdef PNG_READ_GAMMA_SUPPORTED
1365/* The threshold on gamma processing is configurable but hard-wired into the
1366 * library. The following is the floating point variant.
1367 */
1368#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1369
1370/* Handle gamma correction. Screen_gamma=(display_exponent).
1371 * NOTE: this API simply sets the screen and file gamma values. It will
1372 * therefore override the value for gamma in a PNG file if it is called after
1373 * the file header has been read - use with care - call before reading the PNG
1374 * file for best results!
1375 *
1376 * These routines accept the same gamma values as png_set_alpha_mode (described
1377 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1378 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1379 * is the inverse of a 'screen gamma' value.
1380 */
1381PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1382 double screen_gamma, double override_file_gamma))
1383PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1384 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1385#endif
1386
1387#ifdef PNG_WRITE_FLUSH_SUPPORTED
1388/* Set how many lines between output flushes - 0 for no flushing */
1389PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1390/* Flush the current PNG output buffer */
1391PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1392#endif
1393
1394/* Optional update palette with requested transformations */
1395PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1396
1397/* Optional call to update the users info structure */
1398PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1399 png_inforp info_ptr));
1400
1401#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1402/* Read one or more rows of image data. */
1403PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1404 png_bytepp display_row, png_uint_32 num_rows));
1405#endif
1406
1407#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1408/* Read a row of data. */
1409PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1410 png_bytep display_row));
1411#endif
1412
1413#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1414/* Read the whole image into memory at once. */
1415PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1416#endif
1417
1418/* Write a row of image data */
1419PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1420 png_const_bytep row));
1421
1422/* Write a few rows of image data: (*row) is not written; however, the type
1423 * is declared as writeable to maintain compatibility with previous versions
1424 * of libpng and to allow the 'display_row' array from read_rows to be passed
1425 * unchanged to write_rows.
1426 */
1427PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1428 png_uint_32 num_rows));
1429
1430/* Write the image data */
1431PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1432
1433/* Write the end of the PNG file. */
1434PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1435 png_inforp info_ptr));
1436
1437#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1438/* Read the end of the PNG file. */
1439PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1440#endif
1441
1442/* Free any memory associated with the png_info_struct */
1443PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1444 png_infopp info_ptr_ptr));
1445
1446/* Free any memory associated with the png_struct and the png_info_structs */
1447PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1448 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1449
1450/* Free any memory associated with the png_struct and the png_info_structs */
1451PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1452 png_infopp info_ptr_ptr));
1453
1454/* Set the libpng method of handling chunk CRC errors */
1455PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1456 int ancil_action));
1457
1458/* Values for png_set_crc_action() say how to handle CRC errors in
1459 * ancillary and critical chunks, and whether to use the data contained
1460 * therein. Note that it is impossible to "discard" data in a critical
1461 * chunk. For versions prior to 0.90, the action was always error/quit,
1462 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1463 * chunks is warn/discard. These values should NOT be changed.
1464 *
1465 * value action:critical action:ancillary
1466 */
1467#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1468#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1469#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1470#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1471#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1472#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1473
1474#ifdef PNG_WRITE_SUPPORTED
1475/* These functions give the user control over the scan-line filtering in
1476 * libpng and the compression methods used by zlib. These functions are
1477 * mainly useful for testing, as the defaults should work with most users.
1478 * Those users who are tight on memory or want faster performance at the
1479 * expense of compression can modify them. See the compression library
1480 * header file (zlib.h) for an explination of the compression functions.
1481 */
1482
1483/* Set the filtering method(s) used by libpng. Currently, the only valid
1484 * value for "method" is 0.
1485 */
1486PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1487 int filters));
1488#endif /* WRITE */
1489
1490/* Flags for png_set_filter() to say which filters to use. The flags
1491 * are chosen so that they don't conflict with real filter types
1492 * below, in case they are supplied instead of the #defined constants.
1493 * These values should NOT be changed.
1494 */
1495#define PNG_NO_FILTERS 0x00
1496#define PNG_FILTER_NONE 0x08
1497#define PNG_FILTER_SUB 0x10
1498#define PNG_FILTER_UP 0x20
1499#define PNG_FILTER_AVG 0x40
1500#define PNG_FILTER_PAETH 0x80
1501#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
1502#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
1503
1504/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1505 * These defines should NOT be changed.
1506 */
1507#define PNG_FILTER_VALUE_NONE 0
1508#define PNG_FILTER_VALUE_SUB 1
1509#define PNG_FILTER_VALUE_UP 2
1510#define PNG_FILTER_VALUE_AVG 3
1511#define PNG_FILTER_VALUE_PAETH 4
1512#define PNG_FILTER_VALUE_LAST 5
1513
1514#ifdef PNG_WRITE_SUPPORTED
1515#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1516PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1517 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1518 png_const_doublep filter_costs))
1519PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1520 (png_structrp png_ptr, int heuristic_method, int num_weights,
1521 png_const_fixed_point_p filter_weights,
1522 png_const_fixed_point_p filter_costs))
1523#endif /* WRITE_WEIGHTED_FILTER */
1524
1525/* The following are no longer used and will be removed from libpng-1.7: */
1526#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1527#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1528#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1529#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1530
1531/* Set the library compression level. Currently, valid values range from
1532 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1533 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1534 * shown that zlib compression levels 3-6 usually perform as well as level 9
1535 * for PNG images, and do considerably fewer caclulations. In the future,
1536 * these values may not correspond directly to the zlib compression levels.
1537 */
1538#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1539PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1540 int level));
1541
1542PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1543 int mem_level));
1544
1545PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1546 int strategy));
1547
1548/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1549 * smaller value of window_bits if it can do so safely.
1550 */
1551PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1552 int window_bits));
1553
1554PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1555 int method));
1556#endif /* WRITE_CUSTOMIZE_COMPRESSION */
1557
1558#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1559/* Also set zlib parameters for compressing non-IDAT chunks */
1560PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1561 int level));
1562
1563PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1564 int mem_level));
1565
1566PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1567 int strategy));
1568
1569/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1570 * smaller value of window_bits if it can do so safely.
1571 */
1572PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1573 (png_structrp png_ptr, int window_bits));
1574
1575PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1576 int method));
1577#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1578#endif /* WRITE */
1579
1580/* These next functions are called for input/output, memory, and error
1581 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1582 * and call standard C I/O routines such as fread(), fwrite(), and
1583 * fprintf(). These functions can be made to use other I/O routines
1584 * at run time for those applications that need to handle I/O in a
1585 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1586 * more information.
1587 */
1588
1589#ifdef PNG_STDIO_SUPPORTED
1590/* Initialize the input/output for the PNG file to the default functions. */
1591PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1592#endif
1593
1594/* Replace the (error and abort), and warning functions with user
1595 * supplied functions. If no messages are to be printed you must still
1596 * write and use replacement functions. The replacement error_fn should
1597 * still do a longjmp to the last setjmp location if you are using this
1598 * method of error handling. If error_fn or warning_fn is NULL, the
1599 * default function will be used.
1600 */
1601
1602PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1603 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1604
1605/* Return the user pointer associated with the error functions */
1606PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1607
1608/* Replace the default data output functions with a user supplied one(s).
1609 * If buffered output is not used, then output_flush_fn can be set to NULL.
1610 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1611 * output_flush_fn will be ignored (and thus can be NULL).
1612 * It is probably a mistake to use NULL for output_flush_fn if
1613 * write_data_fn is not also NULL unless you have built libpng with
1614 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1615 * default flush function, which uses the standard *FILE structure, will
1616 * be used.
1617 */
1618PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1619 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1620
1621/* Replace the default data input function with a user supplied one. */
1622PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1623 png_rw_ptr read_data_fn));
1624
1625/* Return the user pointer associated with the I/O functions */
1626PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1627
1628PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1629 png_read_status_ptr read_row_fn));
1630
1631PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1632 png_write_status_ptr write_row_fn));
1633
1634#ifdef PNG_USER_MEM_SUPPORTED
1635/* Replace the default memory allocation functions with user supplied one(s). */
1636PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1637 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1638/* Return the user pointer associated with the memory functions */
1639PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1640#endif
1641
1642#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1643PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1644 png_user_transform_ptr read_user_transform_fn));
1645#endif
1646
1647#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1648PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1649 png_user_transform_ptr write_user_transform_fn));
1650#endif
1651
1652#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1653PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1654 png_voidp user_transform_ptr, int user_transform_depth,
1655 int user_transform_channels));
1656/* Return the user pointer associated with the user transform functions */
1657PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1658 (png_const_structrp png_ptr));
1659#endif
1660
1661#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1662/* Return information about the row currently being processed. Note that these
1663 * APIs do not fail but will return unexpected results if called outside a user
1664 * transform callback. Also note that when transforming an interlaced image the
1665 * row number is the row number within the sub-image of the interlace pass, so
1666 * the value will increase to the height of the sub-image (not the full image)
1667 * then reset to 0 for the next pass.
1668 *
1669 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1670 * find the output pixel (x,y) given an interlaced sub-image pixel
1671 * (row,col,pass). (See below for these macros.)
1672 */
1673PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1674PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1675#endif
1676
1677#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1678/* This callback is called only for *unknown* chunks. If
1679 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1680 * chunks to be treated as unknown, however in this case the callback must do
1681 * any processing required by the chunk (e.g. by calling the appropriate
1682 * png_set_ APIs.)
1683 *
1684 * There is no write support - on write, by default, all the chunks in the
1685 * 'unknown' list are written in the specified position.
1686 *
1687 * The integer return from the callback function is interpreted thus:
1688 *
1689 * negative: An error occurred; png_chunk_error will be called.
1690 * zero: The chunk was not handled, the chunk will be saved. A critical
1691 * chunk will cause an error at this point unless it is to be saved.
1692 * positive: The chunk was handled, libpng will ignore/discard it.
1693 *
1694 * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
1695 * how this behavior will change in libpng 1.7
1696 */
1697PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1698 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1699#endif
1700
1701#ifdef PNG_USER_CHUNKS_SUPPORTED
1702PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1703#endif
1704
1705#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1706/* Sets the function callbacks for the push reader, and a pointer to a
1707 * user-defined structure available to the callback functions.
1708 */
1709PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1710 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1711 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1712
1713/* Returns the user pointer associated with the push read functions */
1714PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1715 (png_const_structrp png_ptr));
1716
1717/* Function to be called when data becomes available */
1718PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1719 png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
1720
1721/* A function which may be called *only* within png_process_data to stop the
1722 * processing of any more data. The function returns the number of bytes
1723 * remaining, excluding any that libpng has cached internally. A subsequent
1724 * call to png_process_data must supply these bytes again. If the argument
1725 * 'save' is set to true the routine will first save all the pending data and
1726 * will always return 0.
1727 */
1728PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
1729
1730/* A function which may be called *only* outside (after) a call to
1731 * png_process_data. It returns the number of bytes of data to skip in the
1732 * input. Normally it will return 0, but if it returns a non-zero value the
1733 * application must skip than number of bytes of input data and pass the
1734 * following data to the next call to png_process_data.
1735 */
1736PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1737
1738/* Function that combines rows. 'new_row' is a flag that should come from
1739 * the callback and be non-NULL if anything needs to be done; the library
1740 * stores its own version of the new data internally and ignores the passed
1741 * in value.
1742 */
1743PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1744 png_bytep old_row, png_const_bytep new_row));
1745#endif /* PROGRESSIVE_READ */
1746
1747PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1748 png_alloc_size_t size), PNG_ALLOCATED);
1749/* Added at libpng version 1.4.0 */
1750PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1751 png_alloc_size_t size), PNG_ALLOCATED);
1752
1753/* Added at libpng version 1.2.4 */
1754PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1755 png_alloc_size_t size), PNG_ALLOCATED);
1756
1757/* Frees a pointer allocated by png_malloc() */
1758PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1759
1760/* Free data that was allocated internally */
1761PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1762 png_inforp info_ptr, png_uint_32 free_me, int num));
1763
1764/* Reassign responsibility for freeing existing data, whether allocated
1765 * by libpng or by the application; this works on the png_info structure passed
1766 * in, it does not change the state for other png_info structures.
1767 *
1768 * It is unlikely that this function works correctly as of 1.6.0 and using it
1769 * may result either in memory leaks or double free of allocated data.
1770 */
1771PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1772 png_inforp info_ptr, int freer, png_uint_32 mask));
1773
1774/* Assignments for png_data_freer */
1775#define PNG_DESTROY_WILL_FREE_DATA 1
1776#define PNG_SET_WILL_FREE_DATA 1
1777#define PNG_USER_WILL_FREE_DATA 2
1778/* Flags for png_ptr->free_me and info_ptr->free_me */
1779#define PNG_FREE_HIST 0x0008U
1780#define PNG_FREE_ICCP 0x0010U
1781#define PNG_FREE_SPLT 0x0020U
1782#define PNG_FREE_ROWS 0x0040U
1783#define PNG_FREE_PCAL 0x0080U
1784#define PNG_FREE_SCAL 0x0100U
1785#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1786# define PNG_FREE_UNKN 0x0200U
1787#endif
1788/* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */
1789#define PNG_FREE_PLTE 0x1000U
1790#define PNG_FREE_TRNS 0x2000U
1791#define PNG_FREE_TEXT 0x4000U
1792#define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
1793#define PNG_FREE_ALL 0xffffU
1794#define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1795
1796#ifdef PNG_USER_MEM_SUPPORTED
1797PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1798 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1799PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1800 png_voidp ptr), PNG_DEPRECATED);
1801#endif
1802
1803#ifdef PNG_ERROR_TEXT_SUPPORTED
1804/* Fatal error in PNG image of libpng - can't continue */
1805PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1806 png_const_charp error_message), PNG_NORETURN);
1807
1808/* The same, but the chunk name is prepended to the error string. */
1809PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1810 png_const_charp error_message), PNG_NORETURN);
1811
1812#else
1813/* Fatal error in PNG image of libpng - can't continue */
1814PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1815# define png_error(s1,s2) png_err(s1)
1816# define png_chunk_error(s1,s2) png_err(s1)
1817#endif
1818
1819#ifdef PNG_WARNINGS_SUPPORTED
1820/* Non-fatal error in libpng. Can continue, but may have a problem. */
1821PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1822 png_const_charp warning_message));
1823
1824/* Non-fatal error in libpng, chunk name is prepended to message. */
1825PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1826 png_const_charp warning_message));
1827#else
1828# define png_warning(s1,s2) ((void)(s1))
1829# define png_chunk_warning(s1,s2) ((void)(s1))
1830#endif
1831
1832#ifdef PNG_BENIGN_ERRORS_SUPPORTED
1833/* Benign error in libpng. Can continue, but may have a problem.
1834 * User can choose whether to handle as a fatal error or as a warning. */
1835PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1836 png_const_charp warning_message));
1837
1838#ifdef PNG_READ_SUPPORTED
1839/* Same, chunk name is prepended to message (only during read) */
1840PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1841 png_const_charp warning_message));
1842#endif
1843
1844PNG_EXPORT(109, void, png_set_benign_errors,
1845 (png_structrp png_ptr, int allowed));
1846#else
1847# ifdef PNG_ALLOW_BENIGN_ERRORS
1848# define png_benign_error png_warning
1849# define png_chunk_benign_error png_chunk_warning
1850# else
1851# define png_benign_error png_error
1852# define png_chunk_benign_error png_chunk_error
1853# endif
1854#endif
1855
1856/* The png_set_<chunk> functions are for storing values in the png_info_struct.
1857 * Similarly, the png_get_<chunk> calls are used to read values from the
1858 * png_info_struct, either storing the parameters in the passed variables, or
1859 * setting pointers into the png_info_struct where the data is stored. The
1860 * png_get_<chunk> functions return a non-zero value if the data was available
1861 * in info_ptr, or return zero and do not change any of the parameters if the
1862 * data was not available.
1863 *
1864 * These functions should be used instead of directly accessing png_info
1865 * to avoid problems with future changes in the size and internal layout of
1866 * png_info_struct.
1867 */
1868/* Returns "flag" if chunk data is valid in info_ptr. */
1869PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1870 png_const_inforp info_ptr, png_uint_32 flag));
1871
1872/* Returns number of bytes needed to hold a transformed row. */
1873PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1874 png_const_inforp info_ptr));
1875
1876#ifdef PNG_INFO_IMAGE_SUPPORTED
1877/* Returns row_pointers, which is an array of pointers to scanlines that was
1878 * returned from png_read_png().
1879 */
1880PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
1881 png_const_inforp info_ptr));
1882
1883/* Set row_pointers, which is an array of pointers to scanlines for use
1884 * by png_write_png().
1885 */
1886PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
1887 png_inforp info_ptr, png_bytepp row_pointers));
1888#endif
1889
1890/* Returns number of color channels in image. */
1891PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
1892 png_const_inforp info_ptr));
1893
1894#ifdef PNG_EASY_ACCESS_SUPPORTED
1895/* Returns image width in pixels. */
1896PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
1897 png_const_inforp info_ptr));
1898
1899/* Returns image height in pixels. */
1900PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
1901 png_const_inforp info_ptr));
1902
1903/* Returns image bit_depth. */
1904PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
1905 png_const_inforp info_ptr));
1906
1907/* Returns image color_type. */
1908PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
1909 png_const_inforp info_ptr));
1910
1911/* Returns image filter_type. */
1912PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
1913 png_const_inforp info_ptr));
1914
1915/* Returns image interlace_type. */
1916PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
1917 png_const_inforp info_ptr));
1918
1919/* Returns image compression_type. */
1920PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
1921 png_const_inforp info_ptr));
1922
1923/* Returns image resolution in pixels per meter, from pHYs chunk data. */
1924PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
1925 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1926PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
1927 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1928PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
1929 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1930
1931/* Returns pixel aspect ratio, computed from pHYs chunk data. */
1932PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
1933 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1934PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
1935 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1936
1937/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1938PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
1939 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1940PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
1941 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1942PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
1943 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1944PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
1945 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1946
1947#endif /* EASY_ACCESS */
1948
1949#ifdef PNG_READ_SUPPORTED
1950/* Returns pointer to signature string read from PNG header */
1951PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
1952 png_const_inforp info_ptr));
1953#endif
1954
1955#ifdef PNG_bKGD_SUPPORTED
1956PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
1957 png_inforp info_ptr, png_color_16p *background));
1958#endif
1959
1960#ifdef PNG_bKGD_SUPPORTED
1961PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
1962 png_inforp info_ptr, png_const_color_16p background));
1963#endif
1964
1965#ifdef PNG_cHRM_SUPPORTED
1966PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
1967 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
1968 double *red_y, double *green_x, double *green_y, double *blue_x,
1969 double *blue_y))
1970PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
1971 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
1972 double *green_X, double *green_Y, double *green_Z, double *blue_X,
1973 double *blue_Y, double *blue_Z))
1974PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
1975 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1976 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
1977 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
1978 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
1979 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
1980PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
1981 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1982 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
1983 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
1984 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
1985 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
1986 png_fixed_point *int_blue_Z))
1987#endif
1988
1989#ifdef PNG_cHRM_SUPPORTED
1990PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
1991 png_inforp info_ptr,
1992 double white_x, double white_y, double red_x, double red_y, double green_x,
1993 double green_y, double blue_x, double blue_y))
1994PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
1995 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
1996 double green_X, double green_Y, double green_Z, double blue_X,
1997 double blue_Y, double blue_Z))
1998PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
1999 png_inforp info_ptr, png_fixed_point int_white_x,
2000 png_fixed_point int_white_y, png_fixed_point int_red_x,
2001 png_fixed_point int_red_y, png_fixed_point int_green_x,
2002 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2003 png_fixed_point int_blue_y))
2004PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
2005 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
2006 png_fixed_point int_red_Z, png_fixed_point int_green_X,
2007 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
2008 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
2009 png_fixed_point int_blue_Z))
2010#endif
2011
2012#ifdef PNG_eXIf_SUPPORTED
2013PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
2014 png_inforp info_ptr, png_bytep *exif));
2015PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr,
2016 png_inforp info_ptr, const png_bytep exif));
2017
2018PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr,
2019 png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif));
2020PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr,
2021 png_inforp info_ptr, const png_uint_32 num_exif, const png_bytep exif));
2022#endif
2023
2024#ifdef PNG_gAMA_SUPPORTED
2025PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
2026 png_const_inforp info_ptr, double *file_gamma))
2027PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2028 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2029 png_fixed_point *int_file_gamma))
2030#endif
2031
2032#ifdef PNG_gAMA_SUPPORTED
2033PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2034 png_inforp info_ptr, double file_gamma))
2035PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2036 png_inforp info_ptr, png_fixed_point int_file_gamma))
2037#endif
2038
2039#ifdef PNG_hIST_SUPPORTED
2040PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2041 png_inforp info_ptr, png_uint_16p *hist));
2042PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2043 png_inforp info_ptr, png_const_uint_16p hist));
2044#endif
2045
2046PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2047 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2048 int *bit_depth, int *color_type, int *interlace_method,
2049 int *compression_method, int *filter_method));
2050
2051PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2052 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2053 int color_type, int interlace_method, int compression_method,
2054 int filter_method));
2055
2056#ifdef PNG_oFFs_SUPPORTED
2057PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2058 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2059 int *unit_type));
2060#endif
2061
2062#ifdef PNG_oFFs_SUPPORTED
2063PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2064 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2065 int unit_type));
2066#endif
2067
2068#ifdef PNG_pCAL_SUPPORTED
2069PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2070 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2071 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2072 png_charpp *params));
2073#endif
2074
2075#ifdef PNG_pCAL_SUPPORTED
2076PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2077 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2078 int type, int nparams, png_const_charp units, png_charpp params));
2079#endif
2080
2081#ifdef PNG_pHYs_SUPPORTED
2082PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2083 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2084 int *unit_type));
2085#endif
2086
2087#ifdef PNG_pHYs_SUPPORTED
2088PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2089 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2090#endif
2091
2092PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2093 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2094
2095PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2096 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2097
2098#ifdef PNG_sBIT_SUPPORTED
2099PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2100 png_inforp info_ptr, png_color_8p *sig_bit));
2101#endif
2102
2103#ifdef PNG_sBIT_SUPPORTED
2104PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2105 png_inforp info_ptr, png_const_color_8p sig_bit));
2106#endif
2107
2108#ifdef PNG_sRGB_SUPPORTED
2109PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2110 png_const_inforp info_ptr, int *file_srgb_intent));
2111#endif
2112
2113#ifdef PNG_sRGB_SUPPORTED
2114PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2115 png_inforp info_ptr, int srgb_intent));
2116PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2117 png_inforp info_ptr, int srgb_intent));
2118#endif
2119
2120#ifdef PNG_iCCP_SUPPORTED
2121PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2122 png_inforp info_ptr, png_charpp name, int *compression_type,
2123 png_bytepp profile, png_uint_32 *proflen));
2124#endif
2125
2126#ifdef PNG_iCCP_SUPPORTED
2127PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2128 png_inforp info_ptr, png_const_charp name, int compression_type,
2129 png_const_bytep profile, png_uint_32 proflen));
2130#endif
2131
2132#ifdef PNG_sPLT_SUPPORTED
2133PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2134 png_inforp info_ptr, png_sPLT_tpp entries));
2135#endif
2136
2137#ifdef PNG_sPLT_SUPPORTED
2138PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2139 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2140#endif
2141
2142#ifdef PNG_TEXT_SUPPORTED
2143/* png_get_text also returns the number of text chunks in *num_text */
2144PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2145 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2146#endif
2147
2148/* Note while png_set_text() will accept a structure whose text,
2149 * language, and translated keywords are NULL pointers, the structure
2150 * returned by png_get_text will always contain regular
2151 * zero-terminated C strings. They might be empty strings but
2152 * they will never be NULL pointers.
2153 */
2154
2155#ifdef PNG_TEXT_SUPPORTED
2156PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2157 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2158#endif
2159
2160#ifdef PNG_tIME_SUPPORTED
2161PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2162 png_inforp info_ptr, png_timep *mod_time));
2163#endif
2164
2165#ifdef PNG_tIME_SUPPORTED
2166PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2167 png_inforp info_ptr, png_const_timep mod_time));
2168#endif
2169
2170#ifdef PNG_tRNS_SUPPORTED
2171PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2172 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2173 png_color_16p *trans_color));
2174#endif
2175
2176#ifdef PNG_tRNS_SUPPORTED
2177PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2178 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2179 png_const_color_16p trans_color));
2180#endif
2181
2182#ifdef PNG_sCAL_SUPPORTED
2183PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2184 png_const_inforp info_ptr, int *unit, double *width, double *height))
2185#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2186 defined(PNG_FLOATING_POINT_SUPPORTED)
2187/* NOTE: this API is currently implemented using floating point arithmetic,
2188 * consequently it can only be used on systems with floating point support.
2189 * In any case the range of values supported by png_fixed_point is small and it
2190 * is highly recommended that png_get_sCAL_s be used instead.
2191 */
2192PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2193 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2194 png_fixed_point *width, png_fixed_point *height))
2195#endif
2196PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2197 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2198 png_charpp swidth, png_charpp sheight));
2199
2200PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2201 png_inforp info_ptr, int unit, double width, double height))
2202PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2203 png_inforp info_ptr, int unit, png_fixed_point width,
2204 png_fixed_point height))
2205PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2206 png_inforp info_ptr, int unit,
2207 png_const_charp swidth, png_const_charp sheight));
2208#endif /* sCAL */
2209
2210#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2211/* Provide the default handling for all unknown chunks or, optionally, for
2212 * specific unknown chunks.
2213 *
2214 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2215 * ignored and the default was used, the per-chunk setting only had an effect on
2216 * write. If you wish to have chunk-specific handling on read in code that must
2217 * work on earlier versions you must use a user chunk callback to specify the
2218 * desired handling (keep or discard.)
2219 *
2220 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2221 * parameter is interpreted as follows:
2222 *
2223 * READ:
2224 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2225 * Known chunks: do normal libpng processing, do not keep the chunk (but
2226 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2227 * Unknown chunks: for a specific chunk use the global default, when used
2228 * as the default discard the chunk data.
2229 * PNG_HANDLE_CHUNK_NEVER:
2230 * Discard the chunk data.
2231 * PNG_HANDLE_CHUNK_IF_SAFE:
2232 * Keep the chunk data if the chunk is not critical else raise a chunk
2233 * error.
2234 * PNG_HANDLE_CHUNK_ALWAYS:
2235 * Keep the chunk data.
2236 *
2237 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2238 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2239 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2240 * it simply resets the behavior to the libpng default.
2241 *
2242 * INTERACTION WTIH USER CHUNK CALLBACKS:
2243 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2244 * callback and the callback returns 0; the chunk is then always stored *unless*
2245 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2246 * the global default is *not* used in this case. (In effect the per-chunk
2247 * value is incremented to at least IF_SAFE.)
2248 *
2249 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2250 * per-chunk defaults will be honored. If you want to preserve the current
2251 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2252 * as the default - if you don't do this libpng 1.6 will issue a warning.
2253 *
2254 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2255 * earlier simply return '1' (handled).
2256 *
2257 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2258 * If this is *not* set known chunks will always be handled by libpng and
2259 * will never be stored in the unknown chunk list. Known chunks listed to
2260 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2261 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2262 * by libpng, in addition critical chunks must either be processed by the
2263 * callback or saved.
2264 *
2265 * The IHDR and IEND chunks must not be listed. Because this turns off the
2266 * default handling for chunks that would otherwise be recognized the
2267 * behavior of libpng transformations may well become incorrect!
2268 *
2269 * WRITE:
2270 * When writing chunks the options only apply to the chunks specified by
2271 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2272 * required by png_set_ calls and will always write the core critical chunks
2273 * (as required for PLTE).
2274 *
2275 * Each chunk in the png_set_unknown_chunks list is looked up in the
2276 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2277 * interpreted as follows:
2278 *
2279 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2280 * Write safe-to-copy chunks and write other chunks if the global
2281 * default is set to _ALWAYS, otherwise don't write this chunk.
2282 * PNG_HANDLE_CHUNK_NEVER:
2283 * Do not write the chunk.
2284 * PNG_HANDLE_CHUNK_IF_SAFE:
2285 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2286 * PNG_HANDLE_CHUNK_ALWAYS:
2287 * Write the chunk.
2288 *
2289 * Note that the default behavior is effectively the opposite of the read case -
2290 * in read unknown chunks are not stored by default, in write they are written
2291 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2292 * - on write the safe-to-copy bit is checked, on read the critical bit is
2293 * checked and on read if the chunk is critical an error will be raised.
2294 *
2295 * num_chunks:
2296 * ===========
2297 * If num_chunks is positive, then the "keep" parameter specifies the manner
2298 * for handling only those chunks appearing in the chunk_list array,
2299 * otherwise the chunk list array is ignored.
2300 *
2301 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2302 * unknown chunks, as described above.
2303 *
2304 * If num_chunks is negative, then the "keep" parameter specifies the manner
2305 * for handling all unknown chunks plus all chunks recognized by libpng
2306 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2307 * be processed by libpng.
2308 */
2309#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2310PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2311 int keep, png_const_bytep chunk_list, int num_chunks));
2312#endif /* HANDLE_AS_UNKNOWN */
2313
2314/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2315 * the result is therefore true (non-zero) if special handling is required,
2316 * false for the default handling.
2317 */
2318PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2319 png_const_bytep chunk_name));
2320#endif /* SET_UNKNOWN_CHUNKS */
2321
2322#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2323PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2324 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2325 int num_unknowns));
2326 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2327 * unknowns to the location currently stored in the png_struct. This is
2328 * invariably the wrong value on write. To fix this call the following API
2329 * for each chunk in the list with the correct location. If you know your
2330 * code won't be compiled on earlier versions you can rely on
2331 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2332 * the correct thing.
2333 */
2334
2335PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2336 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2337
2338PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2339 png_inforp info_ptr, png_unknown_chunkpp entries));
2340#endif
2341
2342/* Png_free_data() will turn off the "valid" flag for anything it frees.
2343 * If you need to turn it off for a chunk that your application has freed,
2344 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2345 */
2346PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2347 png_inforp info_ptr, int mask));
2348
2349#ifdef PNG_INFO_IMAGE_SUPPORTED
2350/* The "params" pointer is currently not used and is for future expansion. */
2351#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2352PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2353 int transforms, png_voidp params));
2354#endif
2355#ifdef PNG_WRITE_SUPPORTED
2356PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2357 int transforms, png_voidp params));
2358#endif
2359#endif
2360
2361PNG_EXPORT(180, png_const_charp, png_get_copyright,
2362 (png_const_structrp png_ptr));
2363PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2364 (png_const_structrp png_ptr));
2365PNG_EXPORT(182, png_const_charp, png_get_header_version,
2366 (png_const_structrp png_ptr));
2367PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2368 (png_const_structrp png_ptr));
2369
2370#ifdef PNG_MNG_FEATURES_SUPPORTED
2371PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2372 png_uint_32 mng_features_permitted));
2373#endif
2374
2375/* For use in png_set_keep_unknown, added to version 1.2.6 */
2376#define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2377#define PNG_HANDLE_CHUNK_NEVER 1
2378#define PNG_HANDLE_CHUNK_IF_SAFE 2
2379#define PNG_HANDLE_CHUNK_ALWAYS 3
2380#define PNG_HANDLE_CHUNK_LAST 4
2381
2382/* Strip the prepended error numbers ("#nnn ") from error and warning
2383 * messages before passing them to the error or warning handler.
2384 */
2385#ifdef PNG_ERROR_NUMBERS_SUPPORTED
2386PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2387 png_uint_32 strip_mode));
2388#endif
2389
2390/* Added in libpng-1.2.6 */
2391#ifdef PNG_SET_USER_LIMITS_SUPPORTED
2392PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2393 png_uint_32 user_width_max, png_uint_32 user_height_max));
2394PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2395 (png_const_structrp png_ptr));
2396PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2397 (png_const_structrp png_ptr));
2398/* Added in libpng-1.4.0 */
2399PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2400 png_uint_32 user_chunk_cache_max));
2401PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2402 (png_const_structrp png_ptr));
2403/* Added in libpng-1.4.1 */
2404PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2405 png_alloc_size_t user_chunk_cache_max));
2406PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2407 (png_const_structrp png_ptr));
2408#endif
2409
2410#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2411PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2412 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2413
2414PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2415 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2416
2417PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2418 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2419
2420PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2421 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2422#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2423PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2424 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2425#endif
2426
2427PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2428 png_const_inforp info_ptr))
2429#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2430PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2431 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2432#endif
2433
2434# ifdef PNG_pHYs_SUPPORTED
2435PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2436 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2437 int *unit_type));
2438# endif /* pHYs */
2439#endif /* INCH_CONVERSIONS */
2440
2441/* Added in libpng-1.4.0 */
2442#ifdef PNG_IO_STATE_SUPPORTED
2443PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2444
2445/* Removed from libpng 1.6; use png_get_io_chunk_type. */
2446PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2447 PNG_DEPRECATED)
2448
2449PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2450 (png_const_structrp png_ptr));
2451
2452/* The flags returned by png_get_io_state() are the following: */
2453# define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2454# define PNG_IO_READING 0x0001 /* currently reading */
2455# define PNG_IO_WRITING 0x0002 /* currently writing */
2456# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2457# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2458# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2459# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2460# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2461# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2462#endif /* IO_STATE */
2463
2464/* Interlace support. The following macros are always defined so that if
2465 * libpng interlace handling is turned off the macros may be used to handle
2466 * interlaced images within the application.
2467 */
2468#define PNG_INTERLACE_ADAM7_PASSES 7
2469
2470/* Two macros to return the first row and first column of the original,
2471 * full, image which appears in a given pass. 'pass' is in the range 0
2472 * to 6 and the result is in the range 0 to 7.
2473 */
2474#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2475#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2476
2477/* A macro to return the offset between pixels in the output row for a pair of
2478 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2479 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2480 * COL_OFFSET is from one column to the next, within a row.
2481 */
2482#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2483#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2484
2485/* Two macros to help evaluate the number of rows or columns in each
2486 * pass. This is expressed as a shift - effectively log2 of the number or
2487 * rows or columns in each 8x8 tile of the original image.
2488 */
2489#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2490#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2491
2492/* Hence two macros to determine the number of rows or columns in a given
2493 * pass of an image given its height or width. In fact these macros may
2494 * return non-zero even though the sub-image is empty, because the other
2495 * dimension may be empty for a small image.
2496 */
2497#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2498 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2499#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2500 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2501
2502/* For the reader row callbacks (both progressive and sequential) it is
2503 * necessary to find the row in the output image given a row in an interlaced
2504 * image, so two more macros:
2505 */
2506#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2507 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2508#define PNG_COL_FROM_PASS_COL(x_in, pass) \
2509 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2510
2511/* Two macros which return a boolean (0 or 1) saying whether the given row
2512 * or column is in a particular pass. These use a common utility macro that
2513 * returns a mask for a given pass - the offset 'off' selects the row or
2514 * column version. The mask has the appropriate bit set for each column in
2515 * the tile.
2516 */
2517#define PNG_PASS_MASK(pass,off) ( \
2518 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2519 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2520
2521#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2522 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2523#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2524 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2525
2526#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2527/* With these routines we avoid an integer divide, which will be slower on
2528 * most machines. However, it does take more operations than the corresponding
2529 * divide method, so it may be slower on a few RISC systems. There are two
2530 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2531 *
2532 * Note that the rounding factors are NOT supposed to be the same! 128 and
2533 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2534 * standard method.
2535 *
2536 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2537 */
2538
2539 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2540
2541# define png_composite(composite, fg, alpha, bg) \
2542 { \
2543 png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2544 * (png_uint_16)(alpha) \
2545 + (png_uint_16)(bg)*(png_uint_16)(255 \
2546 - (png_uint_16)(alpha)) + 128); \
2547 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
2548 }
2549
2550# define png_composite_16(composite, fg, alpha, bg) \
2551 { \
2552 png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2553 * (png_uint_32)(alpha) \
2554 + (png_uint_32)(bg)*(65535 \
2555 - (png_uint_32)(alpha)) + 32768); \
2556 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
2557 }
2558
2559#else /* Standard method using integer division */
2560
2561# define png_composite(composite, fg, alpha, bg) \
2562 (composite) = \
2563 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2564 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2565 127) / 255))
2566
2567# define png_composite_16(composite, fg, alpha, bg) \
2568 (composite) = \
2569 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2570 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2571 32767) / 65535))
2572#endif /* READ_COMPOSITE_NODIV */
2573
2574#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2575PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2576PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2577PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2578#endif
2579
2580PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2581 png_const_bytep buf));
2582/* No png_get_int_16 -- may be added if there's a real need for it. */
2583
2584/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2585#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2586PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2587#endif
2588#ifdef PNG_SAVE_INT_32_SUPPORTED
2589PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2590#endif
2591
2592/* Place a 16-bit number into a buffer in PNG byte order.
2593 * The parameter is declared unsigned int, not png_uint_16,
2594 * just to avoid potential problems on pre-ANSI C compilers.
2595 */
2596#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2597PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2598/* No png_save_int_16 -- may be added if there's a real need for it. */
2599#endif
2600
2601#ifdef PNG_USE_READ_MACROS
2602/* Inline macros to do direct reads of bytes from the input buffer.
2603 * The png_get_int_32() routine assumes we are using two's complement
2604 * format for negative values, which is almost certainly true.
2605 */
2606# define PNG_get_uint_32(buf) \
2607 (((png_uint_32)(*(buf)) << 24) + \
2608 ((png_uint_32)(*((buf) + 1)) << 16) + \
2609 ((png_uint_32)(*((buf) + 2)) << 8) + \
2610 ((png_uint_32)(*((buf) + 3))))
2611
2612 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2613 * function) incorrectly returned a value of type png_uint_32.
2614 */
2615# define PNG_get_uint_16(buf) \
2616 ((png_uint_16) \
2617 (((unsigned int)(*(buf)) << 8) + \
2618 ((unsigned int)(*((buf) + 1)))))
2619
2620# define PNG_get_int_32(buf) \
2621 ((png_int_32)((*(buf) & 0x80) \
2622 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2623 : (png_int_32)png_get_uint_32(buf)))
2624
2625/* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2626 * but defining a macro name prefixed with PNG_PREFIX.
2627 */
2628# ifndef PNG_PREFIX
2629# define png_get_uint_32(buf) PNG_get_uint_32(buf)
2630# define png_get_uint_16(buf) PNG_get_uint_16(buf)
2631# define png_get_int_32(buf) PNG_get_int_32(buf)
2632# endif
2633#else
2634# ifdef PNG_PREFIX
2635 /* No macros; revert to the (redefined) function */
2636# define PNG_get_uint_32 (png_get_uint_32)
2637# define PNG_get_uint_16 (png_get_uint_16)
2638# define PNG_get_int_32 (png_get_int_32)
2639# endif
2640#endif
2641
2642#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2643PNG_EXPORT(242, void, png_set_check_for_invalid_index,
2644 (png_structrp png_ptr, int allowed));
2645# ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2646PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
2647 png_const_infop info_ptr));
2648# endif
2649#endif /* CHECK_FOR_INVALID_INDEX */
2650
2651/*******************************************************************************
2652 * Section 5: SIMPLIFIED API
2653 *******************************************************************************
2654 *
2655 * Please read the documentation in libpng-manual.txt (TODO: write said
2656 * documentation) if you don't understand what follows.
2657 *
2658 * The simplified API hides the details of both libpng and the PNG file format
2659 * itself. It allows PNG files to be read into a very limited number of
2660 * in-memory bitmap formats or to be written from the same formats. If these
2661 * formats do not accomodate your needs then you can, and should, use the more
2662 * sophisticated APIs above - these support a wide variety of in-memory formats
2663 * and a wide variety of sophisticated transformations to those formats as well
2664 * as a wide variety of APIs to manipulate ancillary information.
2665 *
2666 * To read a PNG file using the simplified API:
2667 *
2668 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2669 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2670 * (this is REQUIRED, your program may crash if you don't do it.)
2671 * 2) Call the appropriate png_image_begin_read... function.
2672 * 3) Set the png_image 'format' member to the required sample format.
2673 * 4) Allocate a buffer for the image and, if required, the color-map.
2674 * 5) Call png_image_finish_read to read the image and, if required, the
2675 * color-map into your buffers.
2676 *
2677 * There are no restrictions on the format of the PNG input itself; all valid
2678 * color types, bit depths, and interlace methods are acceptable, and the
2679 * input image is transformed as necessary to the requested in-memory format
2680 * during the png_image_finish_read() step. The only caveat is that if you
2681 * request a color-mapped image from a PNG that is full-color or makes
2682 * complex use of an alpha channel the transformation is extremely lossy and the
2683 * result may look terrible.
2684 *
2685 * To write a PNG file using the simplified API:
2686 *
2687 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2688 * 2) Initialize the members of the structure that describe the image, setting
2689 * the 'format' member to the format of the image samples.
2690 * 3) Call the appropriate png_image_write... function with a pointer to the
2691 * image and, if necessary, the color-map to write the PNG data.
2692 *
2693 * png_image is a structure that describes the in-memory format of an image
2694 * when it is being read or defines the in-memory format of an image that you
2695 * need to write:
2696 */
2697#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2698 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2699
2700#define PNG_IMAGE_VERSION 1
2701
2702typedef struct png_control *png_controlp;
2703typedef struct
2704{
2705 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2706 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2707 png_uint_32 width; /* Image width in pixels (columns) */
2708 png_uint_32 height; /* Image height in pixels (rows) */
2709 png_uint_32 format; /* Image format as defined below */
2710 png_uint_32 flags; /* A bit mask containing informational flags */
2711 png_uint_32 colormap_entries;
2712 /* Number of entries in the color-map */
2713
2714 /* In the event of an error or warning the following field will be set to a
2715 * non-zero value and the 'message' field will contain a '\0' terminated
2716 * string with the libpng error or warning message. If both warnings and
2717 * an error were encountered, only the error is recorded. If there
2718 * are multiple warnings, only the first one is recorded.
2719 *
2720 * The upper 30 bits of this value are reserved, the low two bits contain
2721 * a value as follows:
2722 */
2723# define PNG_IMAGE_WARNING 1
2724# define PNG_IMAGE_ERROR 2
2725 /*
2726 * The result is a two-bit code such that a value more than 1 indicates
2727 * a failure in the API just called:
2728 *
2729 * 0 - no warning or error
2730 * 1 - warning
2731 * 2 - error
2732 * 3 - error preceded by warning
2733 */
2734# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2735
2736 png_uint_32 warning_or_error;
2737
2738 char message[64];
2739} png_image, *png_imagep;
2740
2741/* The samples of the image have one to four channels whose components have
2742 * original values in the range 0 to 1.0:
2743 *
2744 * 1: A single gray or luminance channel (G).
2745 * 2: A gray/luminance channel and an alpha channel (GA).
2746 * 3: Three red, green, blue color channels (RGB).
2747 * 4: Three color channels and an alpha channel (RGBA).
2748 *
2749 * The components are encoded in one of two ways:
2750 *
2751 * a) As a small integer, value 0..255, contained in a single byte. For the
2752 * alpha channel the original value is simply value/255. For the color or
2753 * luminance channels the value is encoded according to the sRGB specification
2754 * and matches the 8-bit format expected by typical display devices.
2755 *
2756 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2757 * channel and are suitable for passing to color management software.
2758 *
2759 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2760 * channels can be converted to the original value by dividing by 65535; all
2761 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2762 * the sRGB specification. This encoding is identified by the
2763 * PNG_FORMAT_FLAG_LINEAR flag below.
2764 *
2765 * When the simplified API needs to convert between sRGB and linear colorspaces,
2766 * the actual sRGB transfer curve defined in the sRGB specification (see the
2767 * article at https://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2768 * approximation used elsewhere in libpng.
2769 *
2770 * When an alpha channel is present it is expected to denote pixel coverage
2771 * of the color or luminance channels and is returned as an associated alpha
2772 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2773 * value.
2774 *
2775 * The samples are either contained directly in the image data, between 1 and 8
2776 * bytes per pixel according to the encoding, or are held in a color-map indexed
2777 * by bytes in the image data. In the case of a color-map the color-map entries
2778 * are individual samples, encoded as above, and the image data has one byte per
2779 * pixel to select the relevant sample from the color-map.
2780 */
2781
2782/* PNG_FORMAT_*
2783 *
2784 * #defines to be used in png_image::format. Each #define identifies a
2785 * particular layout of sample data and, if present, alpha values. There are
2786 * separate defines for each of the two component encodings.
2787 *
2788 * A format is built up using single bit flag values. All combinations are
2789 * valid. Formats can be built up from the flag values or you can use one of
2790 * the predefined values below. When testing formats always use the FORMAT_FLAG
2791 * macros to test for individual features - future versions of the library may
2792 * add new flags.
2793 *
2794 * When reading or writing color-mapped images the format should be set to the
2795 * format of the entries in the color-map then png_image_{read,write}_colormap
2796 * called to read or write the color-map and set the format correctly for the
2797 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2798 *
2799 * NOTE: libpng can be built with particular features disabled. If you see
2800 * compiler errors because the definition of one of the following flags has been
2801 * compiled out it is because libpng does not have the required support. It is
2802 * possible, however, for the libpng configuration to enable the format on just
2803 * read or just write; in that case you may see an error at run time. You can
2804 * guard against this by checking for the definition of the appropriate
2805 * "_SUPPORTED" macro, one of:
2806 *
2807 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2808 */
2809#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2810#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2811#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2812#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2813
2814#ifdef PNG_FORMAT_BGR_SUPPORTED
2815# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2816#endif
2817
2818#ifdef PNG_FORMAT_AFIRST_SUPPORTED
2819# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2820#endif
2821
2822#define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */
2823
2824/* Commonly used formats have predefined macros.
2825 *
2826 * First the single byte (sRGB) formats:
2827 */
2828#define PNG_FORMAT_GRAY 0
2829#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2830#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2831#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2832#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2833#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2834#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2835#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2836#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2837
2838/* Then the linear 2-byte formats. When naming these "Y" is used to
2839 * indicate a luminance (gray) channel.
2840 */
2841#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2842#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2843#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2844#define PNG_FORMAT_LINEAR_RGB_ALPHA \
2845 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2846
2847/* With color-mapped formats the image data is one byte for each pixel, the byte
2848 * is an index into the color-map which is formatted as above. To obtain a
2849 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2850 * to one of the above definitions, or you can use one of the definitions below.
2851 */
2852#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2853#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2854#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2855#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2856#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2857#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2858
2859/* PNG_IMAGE macros
2860 *
2861 * These are convenience macros to derive information from a png_image
2862 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2863 * actual image sample values - either the entries in the color-map or the
2864 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2865 * for the pixels and will always return 1 for color-mapped formats. The
2866 * remaining macros return information about the rows in the image and the
2867 * complete image.
2868 *
2869 * NOTE: All the macros that take a png_image::format parameter are compile time
2870 * constants if the format parameter is, itself, a constant. Therefore these
2871 * macros can be used in array declarations and case labels where required.
2872 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2873 * they can be used in #if tests.
2874 *
2875 * First the information about the samples.
2876 */
2877#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2878 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2879 /* Return the total number of channels in a given format: 1..4 */
2880
2881#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2882 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2883 /* Return the size in bytes of a single component of a pixel or color-map
2884 * entry (as appropriate) in the image: 1 or 2.
2885 */
2886
2887#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2888 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2889 /* This is the size of the sample data for one sample. If the image is
2890 * color-mapped it is the size of one color-map entry (and image pixels are
2891 * one byte in size), otherwise it is the size of one image pixel.
2892 */
2893
2894#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2895 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2896 /* The maximum size of the color-map required by the format expressed in a
2897 * count of components. This can be used to compile-time allocate a
2898 * color-map:
2899 *
2900 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2901 *
2902 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2903 *
2904 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2905 * information from one of the png_image_begin_read_ APIs and dynamically
2906 * allocate the required memory.
2907 */
2908
2909/* Corresponding information about the pixels */
2910#define PNG_IMAGE_PIXEL_(test,fmt)\
2911 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2912
2913#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2914 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2915 /* The number of separate channels (components) in a pixel; 1 for a
2916 * color-mapped image.
2917 */
2918
2919#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2920 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2921 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2922 * image.
2923 */
2924
2925#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2926 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2927
2928/* Information about the whole row, or whole image */
2929#define PNG_IMAGE_ROW_STRIDE(image)\
2930 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2931 /* Return the total number of components in a single row of the image; this
2932 * is the minimum 'row stride', the minimum count of components between each
2933 * row. For a color-mapped image this is the minimum number of bytes in a
2934 * row.
2935 *
2936 * WARNING: this macro overflows for some images with more than one component
2937 * and very large image widths. libpng will refuse to process an image where
2938 * this macro would overflow.
2939 */
2940
2941#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2942 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2943 /* Return the size, in bytes, of an image buffer given a png_image and a row
2944 * stride - the number of components to leave space for in each row.
2945 *
2946 * WARNING: this macro overflows a 32-bit integer for some large PNG images,
2947 * libpng will refuse to process an image where such an overflow would occur.
2948 */
2949
2950#define PNG_IMAGE_SIZE(image)\
2951 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2952 /* Return the size, in bytes, of the image in memory given just a png_image;
2953 * the row stride is the minimum stride required for the image.
2954 */
2955
2956#define PNG_IMAGE_COLORMAP_SIZE(image)\
2957 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2958 /* Return the size, in bytes, of the color-map of this image. If the image
2959 * format is not a color-map format this will return a size sufficient for
2960 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2961 * you don't want to allocate a color-map in this case.
2962 */
2963
2964/* PNG_IMAGE_FLAG_*
2965 *
2966 * Flags containing additional information about the image are held in the
2967 * 'flags' field of png_image.
2968 */
2969#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2970 /* This indicates the the RGB values of the in-memory bitmap do not
2971 * correspond to the red, green and blue end-points defined by sRGB.
2972 */
2973
2974#define PNG_IMAGE_FLAG_FAST 0x02
2975 /* On write emphasise speed over compression; the resultant PNG file will be
2976 * larger but will be produced significantly faster, particular for large
2977 * images. Do not use this option for images which will be distributed, only
2978 * used it when producing intermediate files that will be read back in
2979 * repeatedly. For a typical 24-bit image the option will double the read
2980 * speed at the cost of increasing the image size by 25%, however for many
2981 * more compressible images the PNG file can be 10 times larger with only a
2982 * slight speed gain.
2983 */
2984
2985#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
2986 /* On read if the image is a 16-bit per component image and there is no gAMA
2987 * or sRGB chunk assume that the components are sRGB encoded. Notice that
2988 * images output by the simplified API always have gamma information; setting
2989 * this flag only affects the interpretation of 16-bit images from an
2990 * external source. It is recommended that the application expose this flag
2991 * to the user; the user can normally easily recognize the difference between
2992 * linear and sRGB encoding. This flag has no effect on write - the data
2993 * passed to the write APIs must have the correct encoding (as defined
2994 * above.)
2995 *
2996 * If the flag is not set (the default) input 16-bit per component data is
2997 * assumed to be linear.
2998 *
2999 * NOTE: the flag can only be set after the png_image_begin_read_ call,
3000 * because that call initializes the 'flags' field.
3001 */
3002
3003#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
3004/* READ APIs
3005 * ---------
3006 *
3007 * The png_image passed to the read APIs must have been initialized by setting
3008 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
3009 */
3010#ifdef PNG_STDIO_SUPPORTED
3011PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
3012 const char *file_name));
3013 /* The named file is opened for read and the image header is filled in
3014 * from the PNG header in the file.
3015 */
3016
3017PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
3018 FILE* file));
3019 /* The PNG header is read from the stdio FILE object. */
3020#endif /* STDIO */
3021
3022PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
3023 png_const_voidp memory, png_size_t size));
3024 /* The PNG header is read from the given memory buffer. */
3025
3026PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
3027 png_const_colorp background, void *buffer, png_int_32 row_stride,
3028 void *colormap));
3029 /* Finish reading the image into the supplied buffer and clean up the
3030 * png_image structure.
3031 *
3032 * row_stride is the step, in byte or 2-byte units as appropriate,
3033 * between adjacent rows. A positive stride indicates that the top-most row
3034 * is first in the buffer - the normal top-down arrangement. A negative
3035 * stride indicates that the bottom-most row is first in the buffer.
3036 *
3037 * background need only be supplied if an alpha channel must be removed from
3038 * a png_byte format and the removal is to be done by compositing on a solid
3039 * color; otherwise it may be NULL and any composition will be done directly
3040 * onto the buffer. The value is an sRGB color to use for the background,
3041 * for grayscale output the green channel is used.
3042 *
3043 * background must be supplied when an alpha channel must be removed from a
3044 * single byte color-mapped output format, in other words if:
3045 *
3046 * 1) The original format from png_image_begin_read_from_* had
3047 * PNG_FORMAT_FLAG_ALPHA set.
3048 * 2) The format set by the application does not.
3049 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3050 * PNG_FORMAT_FLAG_LINEAR *not* set.
3051 *
3052 * For linear output removing the alpha channel is always done by compositing
3053 * on black and background is ignored.
3054 *
3055 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3056 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3057 * image->colormap_entries will be updated to the actual number of entries
3058 * written to the colormap; this may be less than the original value.
3059 */
3060
3061PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3062 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3063 * NULL. May be called at any time after the structure is initialized.
3064 */
3065#endif /* SIMPLIFIED_READ */
3066
3067#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3068/* WRITE APIS
3069 * ----------
3070 * For write you must initialize a png_image structure to describe the image to
3071 * be written. To do this use memset to set the whole structure to 0 then
3072 * initialize fields describing your image.
3073 *
3074 * version: must be set to PNG_IMAGE_VERSION
3075 * opaque: must be initialized to NULL
3076 * width: image width in pixels
3077 * height: image height in rows
3078 * format: the format of the data (image and color-map) you wish to write
3079 * flags: set to 0 unless one of the defined flags applies; set
3080 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3081 * values do not correspond to the colors in sRGB.
3082 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3083 */
3084#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3085PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3086 const char *file, int convert_to_8bit, const void *buffer,
3087 png_int_32 row_stride, const void *colormap));
3088 /* Write the image to the named file. */
3089
3090PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3091 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3092 const void *colormap));
3093 /* Write the image to the given (FILE*). */
3094#endif /* SIMPLIFIED_WRITE_STDIO */
3095
3096/* With all write APIs if image is in one of the linear formats with 16-bit
3097 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3098 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3099 * encoded PNG file is written.
3100 *
3101 * With color-mapped data formats the colormap parameter point to a color-map
3102 * with at least image->colormap_entries encoded in the specified format. If
3103 * the format is linear the written PNG color-map will be converted to sRGB
3104 * regardless of the convert_to_8_bit flag.
3105 *
3106 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3107 * from one row to the next in component sized units (1 or 2 bytes) and if
3108 * negative indicates a bottom-up row layout in the buffer. If row_stride is
3109 * zero, libpng will calculate it for you from the image width and number of
3110 * channels.
3111 *
3112 * Note that the write API does not support interlacing, sub-8-bit pixels or
3113 * most ancillary chunks. If you need to write text chunks (e.g. for copyright
3114 * notices) you need to use one of the other APIs.
3115 */
3116
3117PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
3118 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
3119 const void *buffer, png_int_32 row_stride, const void *colormap));
3120 /* Write the image to the given memory buffer. The function both writes the
3121 * whole PNG data stream to *memory and updates *memory_bytes with the count
3122 * of bytes written.
3123 *
3124 * 'memory' may be NULL. In this case *memory_bytes is not read however on
3125 * success the number of bytes which would have been written will still be
3126 * stored in *memory_bytes. On failure *memory_bytes will contain 0.
3127 *
3128 * If 'memory' is not NULL it must point to memory[*memory_bytes] of
3129 * writeable memory.
3130 *
3131 * If the function returns success memory[*memory_bytes] (if 'memory' is not
3132 * NULL) contains the written PNG data. *memory_bytes will always be less
3133 * than or equal to the original value.
3134 *
3135 * If the function returns false and *memory_bytes was not changed an error
3136 * occured during write. If *memory_bytes was changed, or is not 0 if
3137 * 'memory' was NULL, the write would have succeeded but for the memory
3138 * buffer being too small. *memory_bytes contains the required number of
3139 * bytes and will be bigger that the original value.
3140 */
3141
3142#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
3143 row_stride, colormap)\
3144 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
3145 row_stride, colormap)
3146 /* Return the amount of memory in 'size' required to compress this image.
3147 * The png_image structure 'image' must be filled in as in the above
3148 * function and must not be changed before the actual write call, the buffer
3149 * and all other parameters must also be identical to that in the final
3150 * write call. The 'size' variable need not be initialized.
3151 *
3152 * NOTE: the macro returns true/false, if false is returned 'size' will be
3153 * set to zero and the write failed and probably will fail if tried again.
3154 */
3155
3156/* You can pre-allocate the buffer by making sure it is of sufficient size
3157 * regardless of the amount of compression achieved. The buffer size will
3158 * always be bigger than the original image and it will never be filled. The
3159 * following macros are provided to assist in allocating the buffer.
3160 */
3161#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
3162 /* The number of uncompressed bytes in the PNG byte encoding of the image;
3163 * uncompressing the PNG IDAT data will give this number of bytes.
3164 *
3165 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
3166 * macro can because of the extra bytes used in the PNG byte encoding. You
3167 * need to avoid this macro if your image size approaches 2^30 in width or
3168 * height. The same goes for the remainder of these macros; they all produce
3169 * bigger numbers than the actual in-memory image size.
3170 */
3171#ifndef PNG_ZLIB_MAX_SIZE
3172# define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
3173 /* An upper bound on the number of compressed bytes given 'b' uncompressed
3174 * bytes. This is based on deflateBounds() in zlib; different
3175 * implementations of zlib compression may conceivably produce more data so
3176 * if your zlib implementation is not zlib itself redefine this macro
3177 * appropriately.
3178 */
3179#endif
3180
3181#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
3182 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
3183 /* An upper bound on the size of the data in the PNG IDAT chunks. */
3184
3185#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
3186 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
3187 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
3188 12U+3U*(image).colormap_entries/*PLTE data*/+\
3189 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
3190 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
3191 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
3192 /* A helper for the following macro; if your compiler cannot handle the
3193 * following macro use this one with the result of
3194 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
3195 * compilers should handle this just fine.)
3196 */
3197
3198#define PNG_IMAGE_PNG_SIZE_MAX(image)\
3199 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
3200 /* An upper bound on the total length of the PNG data stream for 'image'.
3201 * The result is of type png_alloc_size_t, on 32-bit systems this may
3202 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
3203 * run out of buffer space but return a corrected size which should work.
3204 */
3205#endif /* SIMPLIFIED_WRITE */
3206/*******************************************************************************
3207 * END OF SIMPLIFIED API
3208 ******************************************************************************/
3209#endif /* SIMPLIFIED_{READ|WRITE} */
3210
3211/*******************************************************************************
3212 * Section 6: IMPLEMENTATION OPTIONS
3213 *******************************************************************************
3214 *
3215 * Support for arbitrary implementation-specific optimizations. The API allows
3216 * particular options to be turned on or off. 'Option' is the number of the
3217 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3218 * by the PNG_OPTION_ defines below.
3219 *
3220 * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
3221 * are detected at run time, however sometimes it may be impossible
3222 * to do this in user mode, in which case it is necessary to discover
3223 * the capabilities in an OS specific way. Such capabilities are
3224 * listed here when libpng has support for them and must be turned
3225 * ON by the application if present.
3226 *
3227 * SOFTWARE: sometimes software optimizations actually result in performance
3228 * decrease on some architectures or systems, or with some sets of
3229 * PNG images. 'Software' options allow such optimizations to be
3230 * selected at run time.
3231 */
3232#ifdef PNG_SET_OPTION_SUPPORTED
3233#ifdef PNG_ARM_NEON_API_SUPPORTED
3234# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3235#endif
3236#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3237#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3238#ifdef PNG_MIPS_MSA_API_SUPPORTED
3239# define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */
3240#endif
3241#define PNG_IGNORE_ADLER32 8
3242#ifdef PNG_POWERPC_VSX_API_SUPPORTED
3243# define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions supported */
3244#endif
3245#define PNG_OPTION_NEXT 12 /* Next option - numbers must be even */
3246
3247/* Return values: NOTE: there are four values and 'off' is *not* zero */
3248#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3249#define PNG_OPTION_INVALID 1 /* Option number out of range */
3250#define PNG_OPTION_OFF 2
3251#define PNG_OPTION_ON 3
3252
3253PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3254 int onoff));
3255#endif /* SET_OPTION */
3256
3257/*******************************************************************************
3258 * END OF HARDWARE AND SOFTWARE OPTIONS
3259 ******************************************************************************/
3260
3261/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3262 * defs, and in scripts/symbols.def.
3263 */
3264
3265/* The last ordinal number (this is the *last* one already used; the next
3266 * one to use is one more than this.)
3267 */
3268#ifdef PNG_EXPORT_LAST_ORDINAL
3269 PNG_EXPORT_LAST_ORDINAL(249);
3270#endif
3271
3272#ifdef __cplusplus
3273}
3274#endif
3275
3276#endif /* PNG_VERSION_INFO_ONLY */
3277/* Do not put anything past this line */
3278#endif /* PNG_H */
3279