1
2/* png.h - header file for PNG reference library
3 *
4 * libpng version 1.6.22rc01, May 14, 2016
5 *
6 * Copyright (c) 1998-2002,2004,2006-2016 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 1.6.22rc01, May 14, 2016:
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 * Some files in the "contrib" directory and some configure-generated
29 * files that are distributed with libpng have other copyright owners and
30 * are released under other open source licenses.
31 *
32 * libpng versions 1.0.7, July 1, 2000 through 1.6.22rc01, May 14, 2016 are
33 * Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
34 * derived from libpng-1.0.6, and are distributed according to the same
35 * disclaimer and license as libpng-1.0.6 with the following individuals
36 * added to the list of Contributing Authors:
37 *
38 * Simon-Pierre Cadieux
39 * Eric S. Raymond
40 * Mans Rullgard
41 * Cosmin Truta
42 * Gilles Vollant
43 * James Yu
44 *
45 * and with the following additions to the disclaimer:
46 *
47 * There is no warranty against interference with your enjoyment of the
48 * library or against infringement. There is no warranty that our
49 * efforts or the library will fulfill any of your particular purposes
50 * or needs. This library is provided with all faults, and the entire
51 * risk of satisfactory quality, performance, accuracy, and effort is with
52 * the user.
53 *
54 * Some files in the "contrib" directory have other copyright owners and
55 * are released under other open source licenses.
56 *
57 *
58 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
59 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
60 * libpng-0.96, and are distributed according to the same disclaimer and
61 * license as libpng-0.96, with the following individuals added to the list
62 * of Contributing Authors:
63 *
64 * Tom Lane
65 * Glenn Randers-Pehrson
66 * Willem van Schaik
67 *
68 * Some files in the "scripts" directory have different copyright owners
69 * but are also released under this license.
70 *
71 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
72 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
73 * and are distributed according to the same disclaimer and license as
74 * libpng-0.88, with the following individuals added to the list of
75 * Contributing Authors:
76 *
77 * John Bowler
78 * Kevin Bracey
79 * Sam Bushell
80 * Magnus Holmgren
81 * Greg Roelofs
82 * Tom Tanner
83 *
84 * Some files in the "scripts" directory have other copyright owners
85 * but are released under this license.
86 *
87 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
88 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
89 *
90 * For the purposes of this copyright and license, "Contributing Authors"
91 * is defined as the following set of individuals:
92 *
93 * Andreas Dilger
94 * Dave Martindale
95 * Guy Eric Schalnat
96 * Paul Schmidt
97 * Tim Wegner
98 *
99 * The PNG Reference Library is supplied "AS IS". The Contributing Authors
100 * and Group 42, Inc. disclaim all warranties, expressed or implied,
101 * including, without limitation, the warranties of merchantability and of
102 * fitness for any purpose. The Contributing Authors and Group 42, Inc.
103 * assume no liability for direct, indirect, incidental, special, exemplary,
104 * or consequential damages, which may result from the use of the PNG
105 * Reference Library, even if advised of the possibility of such damage.
106 *
107 * Permission is hereby granted to use, copy, modify, and distribute this
108 * source code, or portions hereof, for any purpose, without fee, subject
109 * to the following restrictions:
110 *
111 * 1. The origin of this source code must not be misrepresented.
112 *
113 * 2. Altered versions must be plainly marked as such and must not
114 * be misrepresented as being the original source.
115 *
116 * 3. This Copyright notice may not be removed or altered from any
117 * source or altered source distribution.
118 *
119 * The Contributing Authors and Group 42, Inc. specifically permit, without
120 * fee, and encourage the use of this source code as a component to
121 * supporting the PNG file format in commercial products. If you use this
122 * source code in a product, acknowledgment is not required but would be
123 * appreciated.
124 *
125 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
126 *
127 * TRADEMARK:
128 *
129 * The name "libpng" has not been registered by the Copyright owner
130 * as a trademark in any jurisdiction. However, because libpng has
131 * been distributed and maintained world-wide, continually since 1995,
132 * the Copyright owner claims "common-law trademark protection" in any
133 * jurisdiction where common-law trademark is recognized.
134 *
135 * OSI CERTIFICATION:
136 *
137 * Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
138 * a certification mark of the Open Source Initiative. OSI has not addressed
139 * the additional disclaimers inserted at version 1.0.7.
140 *
141 * EXPORT CONTROL:
142 *
143 * The Copyright owner believes that the Export Control Classification
144 * Number (ECCN) for libpng is EAR99, which means not subject to export
145 * controls or International Traffic in Arms Regulations (ITAR) because
146 * it is open source, publicly available software, that does not contain
147 * any encryption software. See the EAR, paragraphs 734.3(b)(3) and
148 * 734.7(b).
149 */
150
151/*
152 * A "png_get_copyright" function is available, for convenient use in "about"
153 * boxes and the like:
154 *
155 * printf("%s", png_get_copyright(NULL));
156 *
157 * Also, the PNG logo (in PNG format, of course) is supplied in the
158 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
159 */
160
161/*
162 * The contributing authors would like to thank all those who helped
163 * with testing, bug fixes, and patience. This wouldn't have been
164 * possible without all of you.
165 *
166 * Thanks to Frank J. T. Wojcik for helping with the documentation.
167 */
168
169/* Note about libpng version numbers:
170 *
171 * Due to various miscommunications, unforeseen code incompatibilities
172 * and occasional factors outside the authors' control, version numbering
173 * on the library has not always been consistent and straightforward.
174 * The following table summarizes matters since version 0.89c, which was
175 * the first widely used release:
176 *
177 * source png.h png.h shared-lib
178 * version string int version
179 * ------- ------ ----- ----------
180 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
181 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
182 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
183 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
184 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
185 * 0.97c 0.97 97 2.0.97
186 * 0.98 0.98 98 2.0.98
187 * 0.99 0.99 98 2.0.99
188 * 0.99a-m 0.99 99 2.0.99
189 * 1.00 1.00 100 2.1.0 [100 should be 10000]
190 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
191 * 1.0.1 png.h string is 10001 2.1.0
192 * 1.0.1a-e identical to the 10002 from here on, the shared library
193 * 1.0.2 source version) 10002 is 2.V where V is the source code
194 * 1.0.2a-b 10003 version, except as noted.
195 * 1.0.3 10003
196 * 1.0.3a-d 10004
197 * 1.0.4 10004
198 * 1.0.4a-f 10005
199 * 1.0.5 (+ 2 patches) 10005
200 * 1.0.5a-d 10006
201 * 1.0.5e-r 10100 (not source compatible)
202 * 1.0.5s-v 10006 (not binary compatible)
203 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
204 * 1.0.6d-f 10007 (still binary incompatible)
205 * 1.0.6g 10007
206 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
207 * 1.0.6i 10007 10.6i
208 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
209 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
210 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
211 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
212 * 1.0.7 1 10007 (still compatible)
213 * ...
214 * 1.0.19 10 10019 10.so.0.19[.0]
215 * ...
216 * 1.2.56 13 10256 12.so.0.56[.0]
217 * ...
218 * 1.5.25 15 10525 15.so.15.25[.0]
219 * ...
220 * 1.6.22 16 10622 16.so.16.22[.0]
221 *
222 * Henceforth the source version will match the shared-library major
223 * and minor numbers; the shared-library major version number will be
224 * used for changes in backward compatibility, as it is intended. The
225 * PNG_LIBPNG_VER macro, which is not used within libpng but is available
226 * for applications, is an unsigned integer of the form xyyzz corresponding
227 * to the source version x.y.z (leading zeros in y and z). Beta versions
228 * were given the previous public release number plus a letter, until
229 * version 1.0.6j; from then on they were given the upcoming public
230 * release number plus "betaNN" or "rcNN".
231 *
232 * Binary incompatibility exists only when applications make direct access
233 * to the info_ptr or png_ptr members through png.h, and the compiled
234 * application is loaded with a different version of the library.
235 *
236 * DLLNUM will change each time there are forward or backward changes
237 * in binary compatibility (e.g., when a new feature is added).
238 *
239 * See libpng.txt or libpng.3 for more information. The PNG specification
240 * is available as a W3C Recommendation and as an ISO Specification,
241 * <http://www.w3.org/TR/2003/REC-PNG-20031110/
242 */
243
244/*
245 * Y2K compliance in libpng:
246 * =========================
247 *
248 * May 14, 2016
249 *
250 * Since the PNG Development group is an ad-hoc body, we can't make
251 * an official declaration.
252 *
253 * This is your unofficial assurance that libpng from version 0.71 and
254 * upward through 1.6.22rc01 are Y2K compliant. It is my belief that
255 * earlier versions were also Y2K compliant.
256 *
257 * Libpng only has two year fields. One is a 2-byte unsigned integer
258 * that will hold years up to 65535. The other, which is deprecated,
259 * holds the date in text format, and will hold years up to 9999.
260 *
261 * The integer is
262 * "png_uint_16 year" in png_time_struct.
263 *
264 * The string is
265 * "char time_buffer[29]" in png_struct. This is no longer used
266 * in libpng-1.6.x and will be removed from libpng-1.7.0.
267 *
268 * There are seven time-related functions:
269 * png.c: png_convert_to_rfc_1123_buffer() in png.c
270 * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
271 * png_convert_to_rfc_1152() in error prior to libpng-0.98)
272 * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
273 * png_convert_from_time_t() in pngwrite.c
274 * png_get_tIME() in pngget.c
275 * png_handle_tIME() in pngrutil.c, called in pngread.c
276 * png_set_tIME() in pngset.c
277 * png_write_tIME() in pngwutil.c, called in pngwrite.c
278 *
279 * All handle dates properly in a Y2K environment. The
280 * png_convert_from_time_t() function calls gmtime() to convert from system
281 * clock time, which returns (year - 1900), which we properly convert to
282 * the full 4-digit year. There is a possibility that libpng applications
283 * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
284 * function, or that they are incorrectly passing only a 2-digit year
285 * instead of "year - 1900" into the png_convert_from_struct_tm() function,
286 * but this is not under our control. The libpng documentation has always
287 * stated that it works with 4-digit years, and the APIs have been
288 * documented as such.
289 *
290 * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
291 * integer to hold the year, and can hold years as large as 65535.
292 *
293 * zlib, upon which libpng depends, is also Y2K compliant. It contains
294 * no date-related code.
295 *
296 * Glenn Randers-Pehrson
297 * libpng maintainer
298 * PNG Development Group
299 */
300
301#ifndef PNG_H
302#define PNG_H
303
304/* This is not the place to learn how to use libpng. The file libpng-manual.txt
305 * describes how to use libpng, and the file example.c summarizes it
306 * with some code on which to build. This file is useful for looking
307 * at the actual function definitions and structure components. If that
308 * file has been stripped from your copy of libpng, you can find it at
309 * <http://www.libpng.org/pub/png/libpng-manual.txt>
310 *
311 * If you just need to read a PNG file and don't want to read the documentation
312 * skip to the end of this file and read the section entitled 'simplified API'.
313 */
314
315/* Version information for png.h - this should match the version in png.c */
316#define PNG_LIBPNG_VER_STRING "1.6.22rc01"
317#define PNG_HEADER_VERSION_STRING \
318 " libpng version 1.6.22rc01 - May 14, 2016\n"
319
320#define PNG_LIBPNG_VER_SONUM 16
321#define PNG_LIBPNG_VER_DLLNUM 16
322
323/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
324#define PNG_LIBPNG_VER_MAJOR 1
325#define PNG_LIBPNG_VER_MINOR 6
326#define PNG_LIBPNG_VER_RELEASE 22
327
328/* This should match the numeric part of the final component of
329 * PNG_LIBPNG_VER_STRING, omitting any leading zero:
330 */
331
332#define PNG_LIBPNG_VER_BUILD 01
333
334/* Release Status */
335#define PNG_LIBPNG_BUILD_ALPHA 1
336#define PNG_LIBPNG_BUILD_BETA 2
337#define PNG_LIBPNG_BUILD_RC 3
338#define PNG_LIBPNG_BUILD_STABLE 4
339#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
340
341/* Release-Specific Flags */
342#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
343 PNG_LIBPNG_BUILD_STABLE only */
344#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
345 PNG_LIBPNG_BUILD_SPECIAL */
346#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
347 PNG_LIBPNG_BUILD_PRIVATE */
348
349#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_RC
350
351/* Careful here. At one time, Guy wanted to use 082, but that would be octal.
352 * We must not include leading zeros.
353 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
354 * version 1.0.0 was mis-numbered 100 instead of 10000). From
355 * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
356 */
357#define PNG_LIBPNG_VER 10622 /* 1.6.22 */
358
359/* Library configuration: these options cannot be changed after
360 * the library has been built.
361 */
362#ifndef PNGLCONF_H
363 /* If pnglibconf.h is missing, you can
364 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
365 */
366# include "pnglibconf.h"
367#endif
368
369#ifndef PNG_VERSION_INFO_ONLY
370 /* Machine specific configuration. */
371# include "pngconf.h"
372#endif
373
374/*
375 * Added at libpng-1.2.8
376 *
377 * Ref MSDN: Private as priority over Special
378 * VS_FF_PRIVATEBUILD File *was not* built using standard release
379 * procedures. If this value is given, the StringFileInfo block must
380 * contain a PrivateBuild string.
381 *
382 * VS_FF_SPECIALBUILD File *was* built by the original company using
383 * standard release procedures but is a variation of the standard
384 * file of the same version number. If this value is given, the
385 * StringFileInfo block must contain a SpecialBuild string.
386 */
387
388#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
389# define PNG_LIBPNG_BUILD_TYPE \
390 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
391#else
392# ifdef PNG_LIBPNG_SPECIALBUILD
393# define PNG_LIBPNG_BUILD_TYPE \
394 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
395# else
396# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
397# endif
398#endif
399
400#ifndef PNG_VERSION_INFO_ONLY
401
402/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
403#ifdef __cplusplus
404extern "C" {
405#endif /* __cplusplus */
406
407/* Version information for C files, stored in png.c. This had better match
408 * the version above.
409 */
410#define png_libpng_ver png_get_header_ver(NULL)
411
412/* This file is arranged in several sections:
413 *
414 * 1. [omitted]
415 * 2. Any configuration options that can be specified by for the application
416 * code when it is built. (Build time configuration is in pnglibconf.h)
417 * 3. Type definitions (base types are defined in pngconf.h), structure
418 * definitions.
419 * 4. Exported library functions.
420 * 5. Simplified API.
421 * 6. Implementation options.
422 *
423 * The library source code has additional files (principally pngpriv.h) that
424 * allow configuration of the library.
425 */
426
427/* Section 1: [omitted] */
428
429/* Section 2: run time configuration
430 * See pnglibconf.h for build time configuration
431 *
432 * Run time configuration allows the application to choose between
433 * implementations of certain arithmetic APIs. The default is set
434 * at build time and recorded in pnglibconf.h, but it is safe to
435 * override these (and only these) settings. Note that this won't
436 * change what the library does, only application code, and the
437 * settings can (and probably should) be made on a per-file basis
438 * by setting the #defines before including png.h
439 *
440 * Use macros to read integers from PNG data or use the exported
441 * functions?
442 * PNG_USE_READ_MACROS: use the macros (see below) Note that
443 * the macros evaluate their argument multiple times.
444 * PNG_NO_USE_READ_MACROS: call the relevant library function.
445 *
446 * Use the alternative algorithm for compositing alpha samples that
447 * does not use division?
448 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
449 * algorithm.
450 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
451 *
452 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
453 * false?
454 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
455 * APIs to png_warning.
456 * Otherwise the calls are mapped to png_error.
457 */
458
459/* Section 3: type definitions, including structures and compile time
460 * constants.
461 * See pngconf.h for base types that vary by machine/system
462 */
463
464/* This triggers a compiler error in png.c, if png.c and png.h
465 * do not agree upon the version number.
466 */
467typedef char* png_libpng_version_1_6_22rc01;
468
469/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
470 *
471 * png_struct is the cache of information used while reading or writing a single
472 * PNG file. One of these is always required, although the simplified API
473 * (below) hides the creation and destruction of it.
474 */
475typedef struct png_struct_def png_struct;
476typedef const png_struct * png_const_structp;
477typedef png_struct * png_structp;
478typedef png_struct * * png_structpp;
479
480/* png_info contains information read from or to be written to a PNG file. One
481 * or more of these must exist while reading or creating a PNG file. The
482 * information is not used by libpng during read but is used to control what
483 * gets written when a PNG file is created. "png_get_" function calls read
484 * information during read and "png_set_" functions calls write information
485 * when creating a PNG.
486 * been moved into a separate header file that is not accessible to
487 * applications. Read libpng-manual.txt or libpng.3 for more info.
488 */
489typedef struct png_info_def png_info;
490typedef png_info * png_infop;
491typedef const png_info * png_const_infop;
492typedef png_info * * png_infopp;
493
494/* Types with names ending 'p' are pointer types. The corresponding types with
495 * names ending 'rp' are identical pointer types except that the pointer is
496 * marked 'restrict', which means that it is the only pointer to the object
497 * passed to the function. Applications should not use the 'restrict' types;
498 * it is always valid to pass 'p' to a pointer with a function argument of the
499 * corresponding 'rp' type. Different compilers have different rules with
500 * regard to type matching in the presence of 'restrict'. For backward
501 * compatibility libpng callbacks never have 'restrict' in their parameters and,
502 * consequentially, writing portable application code is extremely difficult if
503 * an attempt is made to use 'restrict'.
504 */
505typedef png_struct * PNG_RESTRICT png_structrp;
506typedef const png_struct * PNG_RESTRICT png_const_structrp;
507typedef png_info * PNG_RESTRICT png_inforp;
508typedef const png_info * PNG_RESTRICT png_const_inforp;
509
510/* Three color definitions. The order of the red, green, and blue, (and the
511 * exact size) is not important, although the size of the fields need to
512 * be png_byte or png_uint_16 (as defined below).
513 */
514typedef struct png_color_struct
515{
516 png_byte red;
517 png_byte green;
518 png_byte blue;
519} png_color;
520typedef png_color * png_colorp;
521typedef const png_color * png_const_colorp;
522typedef png_color * * png_colorpp;
523
524typedef struct png_color_16_struct
525{
526 png_byte index; /* used for palette files */
527 png_uint_16 red; /* for use in red green blue files */
528 png_uint_16 green;
529 png_uint_16 blue;
530 png_uint_16 gray; /* for use in grayscale files */
531} png_color_16;
532typedef png_color_16 * png_color_16p;
533typedef const png_color_16 * png_const_color_16p;
534typedef png_color_16 * * png_color_16pp;
535
536typedef struct png_color_8_struct
537{
538 png_byte red; /* for use in red green blue files */
539 png_byte green;
540 png_byte blue;
541 png_byte gray; /* for use in grayscale files */
542 png_byte alpha; /* for alpha channel files */
543} png_color_8;
544typedef png_color_8 * png_color_8p;
545typedef const png_color_8 * png_const_color_8p;
546typedef png_color_8 * * png_color_8pp;
547
548/*
549 * The following two structures are used for the in-core representation
550 * of sPLT chunks.
551 */
552typedef struct png_sPLT_entry_struct
553{
554 png_uint_16 red;
555 png_uint_16 green;
556 png_uint_16 blue;
557 png_uint_16 alpha;
558 png_uint_16 frequency;
559} png_sPLT_entry;
560typedef png_sPLT_entry * png_sPLT_entryp;
561typedef const png_sPLT_entry * png_const_sPLT_entryp;
562typedef png_sPLT_entry * * png_sPLT_entrypp;
563
564/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
565 * occupy the LSB of their respective members, and the MSB of each member
566 * is zero-filled. The frequency member always occupies the full 16 bits.
567 */
568
569typedef struct png_sPLT_struct
570{
571 png_charp name; /* palette name */
572 png_byte depth; /* depth of palette samples */
573 png_sPLT_entryp entries; /* palette entries */
574 png_int_32 nentries; /* number of palette entries */
575} png_sPLT_t;
576typedef png_sPLT_t * png_sPLT_tp;
577typedef const png_sPLT_t * png_const_sPLT_tp;
578typedef png_sPLT_t * * png_sPLT_tpp;
579
580#ifdef PNG_TEXT_SUPPORTED
581/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
582 * and whether that contents is compressed or not. The "key" field
583 * points to a regular zero-terminated C string. The "text" fields can be a
584 * regular C string, an empty string, or a NULL pointer.
585 * However, the structure returned by png_get_text() will always contain
586 * the "text" field as a regular zero-terminated C string (possibly
587 * empty), never a NULL pointer, so it can be safely used in printf() and
588 * other string-handling functions. Note that the "itxt_length", "lang", and
589 * "lang_key" members of the structure only exist when the library is built
590 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
591 * default without iTXt support. Also note that when iTXt *is* supported,
592 * the "lang" and "lang_key" fields contain NULL pointers when the
593 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
594 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
595 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
596 * which is always 0 or 1, or its "compression method" which is always 0.
597 */
598typedef struct png_text_struct
599{
600 int compression; /* compression value:
601 -1: tEXt, none
602 0: zTXt, deflate
603 1: iTXt, none
604 2: iTXt, deflate */
605 png_charp key; /* keyword, 1-79 character description of "text" */
606 png_charp text; /* comment, may be an empty string (ie "")
607 or a NULL pointer */
608 png_size_t text_length; /* length of the text string */
609 png_size_t itxt_length; /* length of the itxt string */
610 png_charp lang; /* language code, 0-79 characters
611 or a NULL pointer */
612 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
613 chars or a NULL pointer */
614} png_text;
615typedef png_text * png_textp;
616typedef const png_text * png_const_textp;
617typedef png_text * * png_textpp;
618#endif
619
620/* Supported compression types for text in PNG files (tEXt, and zTXt).
621 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
622#define PNG_TEXT_COMPRESSION_NONE_WR -3
623#define PNG_TEXT_COMPRESSION_zTXt_WR -2
624#define PNG_TEXT_COMPRESSION_NONE -1
625#define PNG_TEXT_COMPRESSION_zTXt 0
626#define PNG_ITXT_COMPRESSION_NONE 1
627#define PNG_ITXT_COMPRESSION_zTXt 2
628#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
629
630/* png_time is a way to hold the time in an machine independent way.
631 * Two conversions are provided, both from time_t and struct tm. There
632 * is no portable way to convert to either of these structures, as far
633 * as I know. If you know of a portable way, send it to me. As a side
634 * note - PNG has always been Year 2000 compliant!
635 */
636typedef struct png_time_struct
637{
638 png_uint_16 year; /* full year, as in, 1995 */
639 png_byte month; /* month of year, 1 - 12 */
640 png_byte day; /* day of month, 1 - 31 */
641 png_byte hour; /* hour of day, 0 - 23 */
642 png_byte minute; /* minute of hour, 0 - 59 */
643 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
644} png_time;
645typedef png_time * png_timep;
646typedef const png_time * png_const_timep;
647typedef png_time * * png_timepp;
648
649#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
650 defined(PNG_USER_CHUNKS_SUPPORTED)
651/* png_unknown_chunk is a structure to hold queued chunks for which there is
652 * no specific support. The idea is that we can use this to queue
653 * up private chunks for output even though the library doesn't actually
654 * know about their semantics.
655 *
656 * The data in the structure is set by libpng on read and used on write.
657 */
658typedef struct png_unknown_chunk_t
659{
660 png_byte name[5]; /* Textual chunk name with '\0' terminator */
661 png_byte *data; /* Data, should not be modified on read! */
662 png_size_t size;
663
664 /* On write 'location' must be set using the flag values listed below.
665 * Notice that on read it is set by libpng however the values stored have
666 * more bits set than are listed below. Always treat the value as a
667 * bitmask. On write set only one bit - setting multiple bits may cause the
668 * chunk to be written in multiple places.
669 */
670 png_byte location; /* mode of operation at read time */
671}
672png_unknown_chunk;
673
674typedef png_unknown_chunk * png_unknown_chunkp;
675typedef const png_unknown_chunk * png_const_unknown_chunkp;
676typedef png_unknown_chunk * * png_unknown_chunkpp;
677#endif
678
679/* Flag values for the unknown chunk location byte. */
680#define PNG_HAVE_IHDR 0x01
681#define PNG_HAVE_PLTE 0x02
682#define PNG_AFTER_IDAT 0x08
683
684/* Maximum positive integer used in PNG is (2^31)-1 */
685#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
686#define PNG_UINT_32_MAX ((png_uint_32)(-1))
687#define PNG_SIZE_MAX ((png_size_t)(-1))
688
689/* These are constants for fixed point values encoded in the
690 * PNG specification manner (x100000)
691 */
692#define PNG_FP_1 100000
693#define PNG_FP_HALF 50000
694#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
695#define PNG_FP_MIN (-PNG_FP_MAX)
696
697/* These describe the color_type field in png_info. */
698/* color type masks */
699#define PNG_COLOR_MASK_PALETTE 1
700#define PNG_COLOR_MASK_COLOR 2
701#define PNG_COLOR_MASK_ALPHA 4
702
703/* color types. Note that not all combinations are legal */
704#define PNG_COLOR_TYPE_GRAY 0
705#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
706#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
707#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
708#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
709/* aliases */
710#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
711#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
712
713/* This is for compression type. PNG 1.0-1.2 only define the single type. */
714#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
715#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
716
717/* This is for filter type. PNG 1.0-1.2 only define the single type. */
718#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
719#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
720#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
721
722/* These are for the interlacing type. These values should NOT be changed. */
723#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
724#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
725#define PNG_INTERLACE_LAST 2 /* Not a valid value */
726
727/* These are for the oFFs chunk. These values should NOT be changed. */
728#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
729#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
730#define PNG_OFFSET_LAST 2 /* Not a valid value */
731
732/* These are for the pCAL chunk. These values should NOT be changed. */
733#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
734#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
735#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
736#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
737#define PNG_EQUATION_LAST 4 /* Not a valid value */
738
739/* These are for the sCAL chunk. These values should NOT be changed. */
740#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
741#define PNG_SCALE_METER 1 /* meters per pixel */
742#define PNG_SCALE_RADIAN 2 /* radians per pixel */
743#define PNG_SCALE_LAST 3 /* Not a valid value */
744
745/* These are for the pHYs chunk. These values should NOT be changed. */
746#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
747#define PNG_RESOLUTION_METER 1 /* pixels/meter */
748#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
749
750/* These are for the sRGB chunk. These values should NOT be changed. */
751#define PNG_sRGB_INTENT_PERCEPTUAL 0
752#define PNG_sRGB_INTENT_RELATIVE 1
753#define PNG_sRGB_INTENT_SATURATION 2
754#define PNG_sRGB_INTENT_ABSOLUTE 3
755#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
756
757/* This is for text chunks */
758#define PNG_KEYWORD_MAX_LENGTH 79
759
760/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
761#define PNG_MAX_PALETTE_LENGTH 256
762
763/* These determine if an ancillary chunk's data has been successfully read
764 * from the PNG header, or if the application has filled in the corresponding
765 * data in the info_struct to be written into the output file. The values
766 * of the PNG_INFO_<chunk> defines should NOT be changed.
767 */
768#define PNG_INFO_gAMA 0x0001U
769#define PNG_INFO_sBIT 0x0002U
770#define PNG_INFO_cHRM 0x0004U
771#define PNG_INFO_PLTE 0x0008U
772#define PNG_INFO_tRNS 0x0010U
773#define PNG_INFO_bKGD 0x0020U
774#define PNG_INFO_hIST 0x0040U
775#define PNG_INFO_pHYs 0x0080U
776#define PNG_INFO_oFFs 0x0100U
777#define PNG_INFO_tIME 0x0200U
778#define PNG_INFO_pCAL 0x0400U
779#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
780#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
781#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
782#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
783#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
784
785/* This is used for the transformation routines, as some of them
786 * change these values for the row. It also should enable using
787 * the routines for other purposes.
788 */
789typedef struct png_row_info_struct
790{
791 png_uint_32 width; /* width of row */
792 png_size_t rowbytes; /* number of bytes in row */
793 png_byte color_type; /* color type of row */
794 png_byte bit_depth; /* bit depth of row */
795 png_byte channels; /* number of channels (1, 2, 3, or 4) */
796 png_byte pixel_depth; /* bits per pixel (depth * channels) */
797} png_row_info;
798
799typedef png_row_info * png_row_infop;
800typedef png_row_info * * png_row_infopp;
801
802/* These are the function types for the I/O functions and for the functions
803 * that allow the user to override the default I/O functions with his or her
804 * own. The png_error_ptr type should match that of user-supplied warning
805 * and error functions, while the png_rw_ptr type should match that of the
806 * user read/write data functions. Note that the 'write' function must not
807 * modify the buffer it is passed. The 'read' function, on the other hand, is
808 * expected to return the read data in the buffer.
809 */
810typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
811typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
812typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
813typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
814 int));
815typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
816 int));
817
818#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
819typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
820typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
821
822/* The following callback receives png_uint_32 row_number, int pass for the
823 * png_bytep data of the row. When transforming an interlaced image the
824 * row number is the row number within the sub-image of the interlace pass, so
825 * the value will increase to the height of the sub-image (not the full image)
826 * then reset to 0 for the next pass.
827 *
828 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
829 * find the output pixel (x,y) given an interlaced sub-image pixel
830 * (row,col,pass). (See below for these macros.)
831 */
832typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
833 png_uint_32, int));
834#endif
835
836#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
837 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
838typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
839 png_bytep));
840#endif
841
842#ifdef PNG_USER_CHUNKS_SUPPORTED
843typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
844 png_unknown_chunkp));
845#endif
846#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
847/* not used anywhere */
848/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
849#endif
850
851#ifdef PNG_SETJMP_SUPPORTED
852/* This must match the function definition in <setjmp.h>, and the application
853 * must include this before png.h to obtain the definition of jmp_buf. The
854 * function is required to be PNG_NORETURN, but this is not checked. If the
855 * function does return the application will crash via an abort() or similar
856 * system level call.
857 *
858 * If you get a warning here while building the library you may need to make
859 * changes to ensure that pnglibconf.h records the calling convention used by
860 * your compiler. This may be very difficult - try using a different compiler
861 * to build the library!
862 */
863PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
864#endif
865
866/* Transform masks for the high-level interface */
867#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
868#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
869#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
870#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
871#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
872#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
873#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
874#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
875#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
876#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
877#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
878#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
879#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
880/* Added to libpng-1.2.34 */
881#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
882#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
883/* Added to libpng-1.4.0 */
884#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
885/* Added to libpng-1.5.4 */
886#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
887#if INT_MAX >= 0x8000 /* else this might break */
888#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
889#endif
890
891/* Flags for MNG supported features */
892#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
893#define PNG_FLAG_MNG_FILTER_64 0x04
894#define PNG_ALL_MNG_FEATURES 0x05
895
896/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
897 * this allowed the zlib default functions to be used on Windows
898 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
899 * ignores the first argument) should be completely compatible with the
900 * following.
901 */
902typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
903 png_alloc_size_t));
904typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
905
906/* Section 4: exported functions
907 * Here are the function definitions most commonly used. This is not
908 * the place to find out how to use libpng. See libpng-manual.txt for the
909 * full explanation, see example.c for the summary. This just provides
910 * a simple one line description of the use of each function.
911 *
912 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
913 * pngconf.h and in the *.dfn files in the scripts directory.
914 *
915 * PNG_EXPORT(ordinal, type, name, (args));
916 *
917 * ordinal: ordinal that is used while building
918 * *.def files. The ordinal value is only
919 * relevant when preprocessing png.h with
920 * the *.dfn files for building symbol table
921 * entries, and are removed by pngconf.h.
922 * type: return type of the function
923 * name: function name
924 * args: function arguments, with types
925 *
926 * When we wish to append attributes to a function prototype we use
927 * the PNG_EXPORTA() macro instead.
928 *
929 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
930 *
931 * ordinal, type, name, and args: same as in PNG_EXPORT().
932 * attributes: function attributes
933 */
934
935/* Returns the version number of the library */
936PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
937
938/* Tell lib we have already handled the first <num_bytes> magic bytes.
939 * Handling more than 8 bytes from the beginning of the file is an error.
940 */
941PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
942
943/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
944 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
945 * signature, and non-zero otherwise. Having num_to_check == 0 or
946 * start > 7 will always fail (ie return non-zero).
947 */
948PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
949 png_size_t num_to_check));
950
951/* Simple signature checking function. This is the same as calling
952 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
953 */
954#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
955
956/* Allocate and initialize png_ptr struct for reading, and any other memory. */
957PNG_EXPORTA(4, png_structp, png_create_read_struct,
958 (png_const_charp user_png_ver, png_voidp error_ptr,
959 png_error_ptr error_fn, png_error_ptr warn_fn),
960 PNG_ALLOCATED);
961
962/* Allocate and initialize png_ptr struct for writing, and any other memory */
963PNG_EXPORTA(5, png_structp, png_create_write_struct,
964 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
965 png_error_ptr warn_fn),
966 PNG_ALLOCATED);
967
968PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
969 (png_const_structrp png_ptr));
970
971PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
972 png_size_t size));
973
974/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
975 * match up.
976 */
977#ifdef PNG_SETJMP_SUPPORTED
978/* This function returns the jmp_buf built in to *png_ptr. It must be
979 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
980 * unless the default error function is overridden in which case NULL is
981 * acceptable. The size of the jmp_buf is checked against the actual size
982 * allocated by the library - the call will return NULL on a mismatch
983 * indicating an ABI mismatch.
984 */
985PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
986 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
987# define png_jmpbuf(png_ptr) \
988 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
989#else
990# define png_jmpbuf(png_ptr) \
991 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
992#endif
993/* This function should be used by libpng applications in place of
994 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
995 * will use it; otherwise it will call PNG_ABORT(). This function was
996 * added in libpng-1.5.0.
997 */
998PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
999 PNG_NORETURN);
1000
1001#ifdef PNG_READ_SUPPORTED
1002/* Reset the compression stream */
1003PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
1004#endif
1005
1006/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1007#ifdef PNG_USER_MEM_SUPPORTED
1008PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1009 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1010 png_error_ptr warn_fn,
1011 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1012 PNG_ALLOCATED);
1013PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1014 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1015 png_error_ptr warn_fn,
1016 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1017 PNG_ALLOCATED);
1018#endif
1019
1020/* Write the PNG file signature. */
1021PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
1022
1023/* Write a PNG chunk - size, type, (optional) data, CRC. */
1024PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
1025 chunk_name, png_const_bytep data, png_size_t length));
1026
1027/* Write the start of a PNG chunk - length and chunk name. */
1028PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1029 png_const_bytep chunk_name, png_uint_32 length));
1030
1031/* Write the data of a PNG chunk started with png_write_chunk_start(). */
1032PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1033 png_const_bytep data, png_size_t length));
1034
1035/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1036PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1037
1038/* Allocate and initialize the info structure */
1039PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1040 PNG_ALLOCATED);
1041
1042/* DEPRECATED: this function allowed init structures to be created using the
1043 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1044 * the API will be removed in the future.
1045 */
1046PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1047 png_size_t png_info_struct_size), PNG_DEPRECATED);
1048
1049/* Writes all the PNG information before the image. */
1050PNG_EXPORT(20, void, png_write_info_before_PLTE,
1051 (png_structrp png_ptr, png_const_inforp info_ptr));
1052PNG_EXPORT(21, void, png_write_info,
1053 (png_structrp png_ptr, png_const_inforp info_ptr));
1054
1055#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1056/* Read the information before the actual image data. */
1057PNG_EXPORT(22, void, png_read_info,
1058 (png_structrp png_ptr, png_inforp info_ptr));
1059#endif
1060
1061#ifdef PNG_TIME_RFC1123_SUPPORTED
1062 /* Convert to a US string format: there is no localization support in this
1063 * routine. The original implementation used a 29 character buffer in
1064 * png_struct, this will be removed in future versions.
1065 */
1066#if PNG_LIBPNG_VER < 10700
1067/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1068PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1069 png_const_timep ptime),PNG_DEPRECATED);
1070#endif
1071PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1072 png_const_timep ptime));
1073#endif
1074
1075#ifdef PNG_CONVERT_tIME_SUPPORTED
1076/* Convert from a struct tm to png_time */
1077PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1078 const struct tm * ttime));
1079
1080/* Convert from time_t to png_time. Uses gmtime() */
1081PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1082#endif /* CONVERT_tIME */
1083
1084#ifdef PNG_READ_EXPAND_SUPPORTED
1085/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1086PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1087PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1088PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1089PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1090#endif
1091
1092#ifdef PNG_READ_EXPAND_16_SUPPORTED
1093/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1094 * of a tRNS chunk if present.
1095 */
1096PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1097#endif
1098
1099#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1100/* Use blue, green, red order for pixels. */
1101PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1102#endif
1103
1104#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1105/* Expand the grayscale to 24-bit RGB if necessary. */
1106PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1107#endif
1108
1109#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1110/* Reduce RGB to grayscale. */
1111#define PNG_ERROR_ACTION_NONE 1
1112#define PNG_ERROR_ACTION_WARN 2
1113#define PNG_ERROR_ACTION_ERROR 3
1114#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1115
1116PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1117 int error_action, double red, double green))
1118PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1119 int error_action, png_fixed_point red, png_fixed_point green))
1120
1121PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1122 png_ptr));
1123#endif
1124
1125#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1126PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1127 png_colorp palette));
1128#endif
1129
1130#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1131/* How the alpha channel is interpreted - this affects how the color channels
1132 * of a PNG file are returned to the calling application when an alpha channel,
1133 * or a tRNS chunk in a palette file, is present.
1134 *
1135 * This has no effect on the way pixels are written into a PNG output
1136 * datastream. The color samples in a PNG datastream are never premultiplied
1137 * with the alpha samples.
1138 *
1139 * The default is to return data according to the PNG specification: the alpha
1140 * channel is a linear measure of the contribution of the pixel to the
1141 * corresponding composited pixel, and the color channels are unassociated
1142 * (not premultiplied). The gamma encoded color channels must be scaled
1143 * according to the contribution and to do this it is necessary to undo
1144 * the encoding, scale the color values, perform the composition and reencode
1145 * the values. This is the 'PNG' mode.
1146 *
1147 * The alternative is to 'associate' the alpha with the color information by
1148 * storing color channel values that have been scaled by the alpha.
1149 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1150 * (the latter being the two common names for associated alpha color channels).
1151 *
1152 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1153 * value is equal to the maximum value.
1154 *
1155 * The final choice is to gamma encode the alpha channel as well. This is
1156 * broken because, in practice, no implementation that uses this choice
1157 * correctly undoes the encoding before handling alpha composition. Use this
1158 * choice only if other serious errors in the software or hardware you use
1159 * mandate it; the typical serious error is for dark halos to appear around
1160 * opaque areas of the composited PNG image because of arithmetic overflow.
1161 *
1162 * The API function png_set_alpha_mode specifies which of these choices to use
1163 * with an enumerated 'mode' value and the gamma of the required output:
1164 */
1165#define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1166#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1167#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1168#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1169#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1170#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1171
1172PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1173 double output_gamma))
1174PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1175 int mode, png_fixed_point output_gamma))
1176#endif
1177
1178#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1179/* The output_gamma value is a screen gamma in libpng terminology: it expresses
1180 * how to decode the output values, not how they are encoded.
1181 */
1182#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1183#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1184#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1185#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1186#endif
1187
1188/* The following are examples of calls to png_set_alpha_mode to achieve the
1189 * required overall gamma correction and, where necessary, alpha
1190 * premultiplication.
1191 *
1192 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1193 * This is the default libpng handling of the alpha channel - it is not
1194 * pre-multiplied into the color components. In addition the call states
1195 * that the output is for a sRGB system and causes all PNG files without gAMA
1196 * chunks to be assumed to be encoded using sRGB.
1197 *
1198 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1199 * In this case the output is assumed to be something like an sRGB conformant
1200 * display preceeded by a power-law lookup table of power 1.45. This is how
1201 * early Mac systems behaved.
1202 *
1203 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1204 * This is the classic Jim Blinn approach and will work in academic
1205 * environments where everything is done by the book. It has the shortcoming
1206 * of assuming that input PNG data with no gamma information is linear - this
1207 * is unlikely to be correct unless the PNG files where generated locally.
1208 * Most of the time the output precision will be so low as to show
1209 * significant banding in dark areas of the image.
1210 *
1211 * png_set_expand_16(pp);
1212 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1213 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1214 * are assumed to have the sRGB encoding if not marked with a gamma value and
1215 * the output is always 16 bits per component. This permits accurate scaling
1216 * and processing of the data. If you know that your input PNG files were
1217 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1218 * correct value for your system.
1219 *
1220 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1221 * If you just need to composite the PNG image onto an existing background
1222 * and if you control the code that does this you can use the optimization
1223 * setting. In this case you just copy completely opaque pixels to the
1224 * output. For pixels that are not completely transparent (you just skip
1225 * those) you do the composition math using png_composite or png_composite_16
1226 * below then encode the resultant 8-bit or 16-bit values to match the output
1227 * encoding.
1228 *
1229 * Other cases
1230 * If neither the PNG nor the standard linear encoding work for you because
1231 * of the software or hardware you use then you have a big problem. The PNG
1232 * case will probably result in halos around the image. The linear encoding
1233 * will probably result in a washed out, too bright, image (it's actually too
1234 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1235 * substantially reduce the halos. Alternatively try:
1236 *
1237 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1238 * This option will also reduce the halos, but there will be slight dark
1239 * halos round the opaque parts of the image where the background is light.
1240 * In the OPTIMIZED mode the halos will be light halos where the background
1241 * is dark. Take your pick - the halos are unavoidable unless you can get
1242 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1243 * faster.)
1244 *
1245 * When the default gamma of PNG files doesn't match the output gamma.
1246 * If you have PNG files with no gamma information png_set_alpha_mode allows
1247 * you to provide a default gamma, but it also sets the ouput gamma to the
1248 * matching value. If you know your PNG files have a gamma that doesn't
1249 * match the output you can take advantage of the fact that
1250 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1251 * default if it is not already set:
1252 *
1253 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1254 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1255 * The first call sets both the default and the output gamma values, the
1256 * second call overrides the output gamma without changing the default. This
1257 * is easier than achieving the same effect with png_set_gamma. You must use
1258 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1259 * fire if more than one call to png_set_alpha_mode and png_set_background is
1260 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1261 * are ignored.
1262 */
1263
1264#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1265PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1266#endif
1267
1268#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1269 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1270PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1271#endif
1272
1273#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1274 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1275PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1276#endif
1277
1278#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1279/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1280PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1281 int flags));
1282/* The values of the PNG_FILLER_ defines should NOT be changed */
1283# define PNG_FILLER_BEFORE 0
1284# define PNG_FILLER_AFTER 1
1285/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1286PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1287 png_uint_32 filler, int flags));
1288#endif /* READ_FILLER || WRITE_FILLER */
1289
1290#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1291/* Swap bytes in 16-bit depth files. */
1292PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1293#endif
1294
1295#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1296/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1297PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1298#endif
1299
1300#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1301 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1302/* Swap packing order of pixels in bytes. */
1303PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1304#endif
1305
1306#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1307/* Converts files to legal bit depths. */
1308PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1309 true_bits));
1310#endif
1311
1312#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1313 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1314/* Have the code handle the interlacing. Returns the number of passes.
1315 * MUST be called before png_read_update_info or png_start_read_image,
1316 * otherwise it will not have the desired effect. Note that it is still
1317 * necessary to call png_read_row or png_read_rows png_get_image_height
1318 * times for each pass.
1319*/
1320PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1321#endif
1322
1323#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1324/* Invert monochrome files */
1325PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1326#endif
1327
1328#ifdef PNG_READ_BACKGROUND_SUPPORTED
1329/* Handle alpha and tRNS by replacing with a background color. Prior to
1330 * libpng-1.5.4 this API must not be called before the PNG file header has been
1331 * read. Doing so will result in unexpected behavior and possible warnings or
1332 * errors if the PNG file contains a bKGD chunk.
1333 */
1334PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1335 png_const_color_16p background_color, int background_gamma_code,
1336 int need_expand, double background_gamma))
1337PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1338 png_const_color_16p background_color, int background_gamma_code,
1339 int need_expand, png_fixed_point background_gamma))
1340#endif
1341#ifdef PNG_READ_BACKGROUND_SUPPORTED
1342# define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1343# define PNG_BACKGROUND_GAMMA_SCREEN 1
1344# define PNG_BACKGROUND_GAMMA_FILE 2
1345# define PNG_BACKGROUND_GAMMA_UNIQUE 3
1346#endif
1347
1348#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1349/* Scale a 16-bit depth file down to 8-bit, accurately. */
1350PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1351#endif
1352
1353#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1354#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
1355/* Strip the second byte of information from a 16-bit depth file. */
1356PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1357#endif
1358
1359#ifdef PNG_READ_QUANTIZE_SUPPORTED
1360/* Turn on quantizing, and reduce the palette to the number of colors
1361 * available.
1362 */
1363PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1364 png_colorp palette, int num_palette, int maximum_colors,
1365 png_const_uint_16p histogram, int full_quantize));
1366#endif
1367
1368#ifdef PNG_READ_GAMMA_SUPPORTED
1369/* The threshold on gamma processing is configurable but hard-wired into the
1370 * library. The following is the floating point variant.
1371 */
1372#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1373
1374/* Handle gamma correction. Screen_gamma=(display_exponent).
1375 * NOTE: this API simply sets the screen and file gamma values. It will
1376 * therefore override the value for gamma in a PNG file if it is called after
1377 * the file header has been read - use with care - call before reading the PNG
1378 * file for best results!
1379 *
1380 * These routines accept the same gamma values as png_set_alpha_mode (described
1381 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1382 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1383 * is the inverse of a 'screen gamma' value.
1384 */
1385PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1386 double screen_gamma, double override_file_gamma))
1387PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1388 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1389#endif
1390
1391#ifdef PNG_WRITE_FLUSH_SUPPORTED
1392/* Set how many lines between output flushes - 0 for no flushing */
1393PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1394/* Flush the current PNG output buffer */
1395PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1396#endif
1397
1398/* Optional update palette with requested transformations */
1399PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1400
1401/* Optional call to update the users info structure */
1402PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1403 png_inforp info_ptr));
1404
1405#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1406/* Read one or more rows of image data. */
1407PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1408 png_bytepp display_row, png_uint_32 num_rows));
1409#endif
1410
1411#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1412/* Read a row of data. */
1413PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1414 png_bytep display_row));
1415#endif
1416
1417#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1418/* Read the whole image into memory at once. */
1419PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1420#endif
1421
1422/* Write a row of image data */
1423PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1424 png_const_bytep row));
1425
1426/* Write a few rows of image data: (*row) is not written; however, the type
1427 * is declared as writeable to maintain compatibility with previous versions
1428 * of libpng and to allow the 'display_row' array from read_rows to be passed
1429 * unchanged to write_rows.
1430 */
1431PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1432 png_uint_32 num_rows));
1433
1434/* Write the image data */
1435PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1436
1437/* Write the end of the PNG file. */
1438PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1439 png_inforp info_ptr));
1440
1441#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1442/* Read the end of the PNG file. */
1443PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1444#endif
1445
1446/* Free any memory associated with the png_info_struct */
1447PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1448 png_infopp info_ptr_ptr));
1449
1450/* Free any memory associated with the png_struct and the png_info_structs */
1451PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1452 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1453
1454/* Free any memory associated with the png_struct and the png_info_structs */
1455PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1456 png_infopp info_ptr_ptr));
1457
1458/* Set the libpng method of handling chunk CRC errors */
1459PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1460 int ancil_action));
1461
1462/* Values for png_set_crc_action() say how to handle CRC errors in
1463 * ancillary and critical chunks, and whether to use the data contained
1464 * therein. Note that it is impossible to "discard" data in a critical
1465 * chunk. For versions prior to 0.90, the action was always error/quit,
1466 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1467 * chunks is warn/discard. These values should NOT be changed.
1468 *
1469 * value action:critical action:ancillary
1470 */
1471#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1472#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1473#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1474#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1475#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1476#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1477
1478#ifdef PNG_WRITE_SUPPORTED
1479/* These functions give the user control over the scan-line filtering in
1480 * libpng and the compression methods used by zlib. These functions are
1481 * mainly useful for testing, as the defaults should work with most users.
1482 * Those users who are tight on memory or want faster performance at the
1483 * expense of compression can modify them. See the compression library
1484 * header file (zlib.h) for an explination of the compression functions.
1485 */
1486
1487/* Set the filtering method(s) used by libpng. Currently, the only valid
1488 * value for "method" is 0.
1489 */
1490PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1491 int filters));
1492#endif /* WRITE */
1493
1494/* Flags for png_set_filter() to say which filters to use. The flags
1495 * are chosen so that they don't conflict with real filter types
1496 * below, in case they are supplied instead of the #defined constants.
1497 * These values should NOT be changed.
1498 */
1499#define PNG_NO_FILTERS 0x00
1500#define PNG_FILTER_NONE 0x08
1501#define PNG_FILTER_SUB 0x10
1502#define PNG_FILTER_UP 0x20
1503#define PNG_FILTER_AVG 0x40
1504#define PNG_FILTER_PAETH 0x80
1505#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
1506#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
1507
1508/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1509 * These defines should NOT be changed.
1510 */
1511#define PNG_FILTER_VALUE_NONE 0
1512#define PNG_FILTER_VALUE_SUB 1
1513#define PNG_FILTER_VALUE_UP 2
1514#define PNG_FILTER_VALUE_AVG 3
1515#define PNG_FILTER_VALUE_PAETH 4
1516#define PNG_FILTER_VALUE_LAST 5
1517
1518#ifdef PNG_WRITE_SUPPORTED
1519#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1520PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1521 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1522 png_const_doublep filter_costs))
1523PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1524 (png_structrp png_ptr, int heuristic_method, int num_weights,
1525 png_const_fixed_point_p filter_weights,
1526 png_const_fixed_point_p filter_costs))
1527#endif /* WRITE_WEIGHTED_FILTER */
1528
1529/* The following are no longer used and will be removed from libpng-1.7: */
1530#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1531#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1532#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1533#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1534
1535/* Set the library compression level. Currently, valid values range from
1536 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1537 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1538 * shown that zlib compression levels 3-6 usually perform as well as level 9
1539 * for PNG images, and do considerably fewer caclulations. In the future,
1540 * these values may not correspond directly to the zlib compression levels.
1541 */
1542#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1543PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1544 int level));
1545
1546PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1547 int mem_level));
1548
1549PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1550 int strategy));
1551
1552/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1553 * smaller value of window_bits if it can do so safely.
1554 */
1555PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1556 int window_bits));
1557
1558PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1559 int method));
1560#endif /* WRITE_CUSTOMIZE_COMPRESSION */
1561
1562#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1563/* Also set zlib parameters for compressing non-IDAT chunks */
1564PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1565 int level));
1566
1567PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1568 int mem_level));
1569
1570PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1571 int strategy));
1572
1573/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1574 * smaller value of window_bits if it can do so safely.
1575 */
1576PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1577 (png_structrp png_ptr, int window_bits));
1578
1579PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1580 int method));
1581#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1582#endif /* WRITE */
1583
1584/* These next functions are called for input/output, memory, and error
1585 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1586 * and call standard C I/O routines such as fread(), fwrite(), and
1587 * fprintf(). These functions can be made to use other I/O routines
1588 * at run time for those applications that need to handle I/O in a
1589 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1590 * more information.
1591 */
1592
1593#ifdef PNG_STDIO_SUPPORTED
1594/* Initialize the input/output for the PNG file to the default functions. */
1595PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1596#endif
1597
1598/* Replace the (error and abort), and warning functions with user
1599 * supplied functions. If no messages are to be printed you must still
1600 * write and use replacement functions. The replacement error_fn should
1601 * still do a longjmp to the last setjmp location if you are using this
1602 * method of error handling. If error_fn or warning_fn is NULL, the
1603 * default function will be used.
1604 */
1605
1606PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1607 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1608
1609/* Return the user pointer associated with the error functions */
1610PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1611
1612/* Replace the default data output functions with a user supplied one(s).
1613 * If buffered output is not used, then output_flush_fn can be set to NULL.
1614 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1615 * output_flush_fn will be ignored (and thus can be NULL).
1616 * It is probably a mistake to use NULL for output_flush_fn if
1617 * write_data_fn is not also NULL unless you have built libpng with
1618 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1619 * default flush function, which uses the standard *FILE structure, will
1620 * be used.
1621 */
1622PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1623 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1624
1625/* Replace the default data input function with a user supplied one. */
1626PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1627 png_rw_ptr read_data_fn));
1628
1629/* Return the user pointer associated with the I/O functions */
1630PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1631
1632PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1633 png_read_status_ptr read_row_fn));
1634
1635PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1636 png_write_status_ptr write_row_fn));
1637
1638#ifdef PNG_USER_MEM_SUPPORTED
1639/* Replace the default memory allocation functions with user supplied one(s). */
1640PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1641 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1642/* Return the user pointer associated with the memory functions */
1643PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1644#endif
1645
1646#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1647PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1648 png_user_transform_ptr read_user_transform_fn));
1649#endif
1650
1651#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1652PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1653 png_user_transform_ptr write_user_transform_fn));
1654#endif
1655
1656#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1657PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1658 png_voidp user_transform_ptr, int user_transform_depth,
1659 int user_transform_channels));
1660/* Return the user pointer associated with the user transform functions */
1661PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1662 (png_const_structrp png_ptr));
1663#endif
1664
1665#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1666/* Return information about the row currently being processed. Note that these
1667 * APIs do not fail but will return unexpected results if called outside a user
1668 * transform callback. Also note that when transforming an interlaced image the
1669 * row number is the row number within the sub-image of the interlace pass, so
1670 * the value will increase to the height of the sub-image (not the full image)
1671 * then reset to 0 for the next pass.
1672 *
1673 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1674 * find the output pixel (x,y) given an interlaced sub-image pixel
1675 * (row,col,pass). (See below for these macros.)
1676 */
1677PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1678PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1679#endif
1680
1681#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1682/* This callback is called only for *unknown* chunks. If
1683 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1684 * chunks to be treated as unknown, however in this case the callback must do
1685 * any processing required by the chunk (e.g. by calling the appropriate
1686 * png_set_ APIs.)
1687 *
1688 * There is no write support - on write, by default, all the chunks in the
1689 * 'unknown' list are written in the specified position.
1690 *
1691 * The integer return from the callback function is interpreted thus:
1692 *
1693 * negative: An error occurred; png_chunk_error will be called.
1694 * zero: The chunk was not handled, the chunk will be saved. A critical
1695 * chunk will cause an error at this point unless it is to be saved.
1696 * positive: The chunk was handled, libpng will ignore/discard it.
1697 *
1698 * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
1699 * how this behavior will change in libpng 1.7
1700 */
1701PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1702 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1703#endif
1704
1705#ifdef PNG_USER_CHUNKS_SUPPORTED
1706PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1707#endif
1708
1709#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1710/* Sets the function callbacks for the push reader, and a pointer to a
1711 * user-defined structure available to the callback functions.
1712 */
1713PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1714 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1715 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1716
1717/* Returns the user pointer associated with the push read functions */
1718PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1719 (png_const_structrp png_ptr));
1720
1721/* Function to be called when data becomes available */
1722PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1723 png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
1724
1725/* A function which may be called *only* within png_process_data to stop the
1726 * processing of any more data. The function returns the number of bytes
1727 * remaining, excluding any that libpng has cached internally. A subsequent
1728 * call to png_process_data must supply these bytes again. If the argument
1729 * 'save' is set to true the routine will first save all the pending data and
1730 * will always return 0.
1731 */
1732PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
1733
1734/* A function which may be called *only* outside (after) a call to
1735 * png_process_data. It returns the number of bytes of data to skip in the
1736 * input. Normally it will return 0, but if it returns a non-zero value the
1737 * application must skip than number of bytes of input data and pass the
1738 * following data to the next call to png_process_data.
1739 */
1740PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1741
1742/* Function that combines rows. 'new_row' is a flag that should come from
1743 * the callback and be non-NULL if anything needs to be done; the library
1744 * stores its own version of the new data internally and ignores the passed
1745 * in value.
1746 */
1747PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1748 png_bytep old_row, png_const_bytep new_row));
1749#endif /* PROGRESSIVE_READ */
1750
1751PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1752 png_alloc_size_t size), PNG_ALLOCATED);
1753/* Added at libpng version 1.4.0 */
1754PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1755 png_alloc_size_t size), PNG_ALLOCATED);
1756
1757/* Added at libpng version 1.2.4 */
1758PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1759 png_alloc_size_t size), PNG_ALLOCATED);
1760
1761/* Frees a pointer allocated by png_malloc() */
1762PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1763
1764/* Free data that was allocated internally */
1765PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1766 png_inforp info_ptr, png_uint_32 free_me, int num));
1767
1768/* Reassign responsibility for freeing existing data, whether allocated
1769 * by libpng or by the application; this works on the png_info structure passed
1770 * in, it does not change the state for other png_info structures.
1771 *
1772 * It is unlikely that this function works correctly as of 1.6.0 and using it
1773 * may result either in memory leaks or double free of allocated data.
1774 */
1775PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1776 png_inforp info_ptr, int freer, png_uint_32 mask));
1777
1778/* Assignments for png_data_freer */
1779#define PNG_DESTROY_WILL_FREE_DATA 1
1780#define PNG_SET_WILL_FREE_DATA 1
1781#define PNG_USER_WILL_FREE_DATA 2
1782/* Flags for png_ptr->free_me and info_ptr->free_me */
1783#define PNG_FREE_HIST 0x0008U
1784#define PNG_FREE_ICCP 0x0010U
1785#define PNG_FREE_SPLT 0x0020U
1786#define PNG_FREE_ROWS 0x0040U
1787#define PNG_FREE_PCAL 0x0080U
1788#define PNG_FREE_SCAL 0x0100U
1789#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1790# define PNG_FREE_UNKN 0x0200U
1791#endif
1792/* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */
1793#define PNG_FREE_PLTE 0x1000U
1794#define PNG_FREE_TRNS 0x2000U
1795#define PNG_FREE_TEXT 0x4000U
1796#define PNG_FREE_ALL 0x7fffU
1797#define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1798
1799#ifdef PNG_USER_MEM_SUPPORTED
1800PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1801 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1802PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1803 png_voidp ptr), PNG_DEPRECATED);
1804#endif
1805
1806#ifdef PNG_ERROR_TEXT_SUPPORTED
1807/* Fatal error in PNG image of libpng - can't continue */
1808PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1809 png_const_charp error_message), PNG_NORETURN);
1810
1811/* The same, but the chunk name is prepended to the error string. */
1812PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1813 png_const_charp error_message), PNG_NORETURN);
1814
1815#else
1816/* Fatal error in PNG image of libpng - can't continue */
1817PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1818# define png_error(s1,s2) png_err(s1)
1819# define png_chunk_error(s1,s2) png_err(s1)
1820#endif
1821
1822#ifdef PNG_WARNINGS_SUPPORTED
1823/* Non-fatal error in libpng. Can continue, but may have a problem. */
1824PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1825 png_const_charp warning_message));
1826
1827/* Non-fatal error in libpng, chunk name is prepended to message. */
1828PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1829 png_const_charp warning_message));
1830#else
1831# define png_warning(s1,s2) ((void)(s1))
1832# define png_chunk_warning(s1,s2) ((void)(s1))
1833#endif
1834
1835#ifdef PNG_BENIGN_ERRORS_SUPPORTED
1836/* Benign error in libpng. Can continue, but may have a problem.
1837 * User can choose whether to handle as a fatal error or as a warning. */
1838PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1839 png_const_charp warning_message));
1840
1841#ifdef PNG_READ_SUPPORTED
1842/* Same, chunk name is prepended to message (only during read) */
1843PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1844 png_const_charp warning_message));
1845#endif
1846
1847PNG_EXPORT(109, void, png_set_benign_errors,
1848 (png_structrp png_ptr, int allowed));
1849#else
1850# ifdef PNG_ALLOW_BENIGN_ERRORS
1851# define png_benign_error png_warning
1852# define png_chunk_benign_error png_chunk_warning
1853# else
1854# define png_benign_error png_error
1855# define png_chunk_benign_error png_chunk_error
1856# endif
1857#endif
1858
1859/* The png_set_<chunk> functions are for storing values in the png_info_struct.
1860 * Similarly, the png_get_<chunk> calls are used to read values from the
1861 * png_info_struct, either storing the parameters in the passed variables, or
1862 * setting pointers into the png_info_struct where the data is stored. The
1863 * png_get_<chunk> functions return a non-zero value if the data was available
1864 * in info_ptr, or return zero and do not change any of the parameters if the
1865 * data was not available.
1866 *
1867 * These functions should be used instead of directly accessing png_info
1868 * to avoid problems with future changes in the size and internal layout of
1869 * png_info_struct.
1870 */
1871/* Returns "flag" if chunk data is valid in info_ptr. */
1872PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1873 png_const_inforp info_ptr, png_uint_32 flag));
1874
1875/* Returns number of bytes needed to hold a transformed row. */
1876PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1877 png_const_inforp info_ptr));
1878
1879#ifdef PNG_INFO_IMAGE_SUPPORTED
1880/* Returns row_pointers, which is an array of pointers to scanlines that was
1881 * returned from png_read_png().
1882 */
1883PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
1884 png_const_inforp info_ptr));
1885
1886/* Set row_pointers, which is an array of pointers to scanlines for use
1887 * by png_write_png().
1888 */
1889PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
1890 png_inforp info_ptr, png_bytepp row_pointers));
1891#endif
1892
1893/* Returns number of color channels in image. */
1894PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
1895 png_const_inforp info_ptr));
1896
1897#ifdef PNG_EASY_ACCESS_SUPPORTED
1898/* Returns image width in pixels. */
1899PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
1900 png_const_inforp info_ptr));
1901
1902/* Returns image height in pixels. */
1903PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
1904 png_const_inforp info_ptr));
1905
1906/* Returns image bit_depth. */
1907PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
1908 png_const_inforp info_ptr));
1909
1910/* Returns image color_type. */
1911PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
1912 png_const_inforp info_ptr));
1913
1914/* Returns image filter_type. */
1915PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
1916 png_const_inforp info_ptr));
1917
1918/* Returns image interlace_type. */
1919PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
1920 png_const_inforp info_ptr));
1921
1922/* Returns image compression_type. */
1923PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
1924 png_const_inforp info_ptr));
1925
1926/* Returns image resolution in pixels per meter, from pHYs chunk data. */
1927PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
1928 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1929PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
1930 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1931PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
1932 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1933
1934/* Returns pixel aspect ratio, computed from pHYs chunk data. */
1935PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
1936 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1937PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
1938 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1939
1940/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1941PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
1942 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1943PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
1944 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1945PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
1946 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1947PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
1948 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1949
1950#endif /* EASY_ACCESS */
1951
1952#ifdef PNG_READ_SUPPORTED
1953/* Returns pointer to signature string read from PNG header */
1954PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
1955 png_const_inforp info_ptr));
1956#endif
1957
1958#ifdef PNG_bKGD_SUPPORTED
1959PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
1960 png_inforp info_ptr, png_color_16p *background));
1961#endif
1962
1963#ifdef PNG_bKGD_SUPPORTED
1964PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
1965 png_inforp info_ptr, png_const_color_16p background));
1966#endif
1967
1968#ifdef PNG_cHRM_SUPPORTED
1969PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
1970 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
1971 double *red_y, double *green_x, double *green_y, double *blue_x,
1972 double *blue_y))
1973PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
1974 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
1975 double *green_X, double *green_Y, double *green_Z, double *blue_X,
1976 double *blue_Y, double *blue_Z))
1977PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
1978 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1979 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
1980 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
1981 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
1982 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
1983PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
1984 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1985 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
1986 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
1987 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
1988 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
1989 png_fixed_point *int_blue_Z))
1990#endif
1991
1992#ifdef PNG_cHRM_SUPPORTED
1993PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
1994 png_inforp info_ptr,
1995 double white_x, double white_y, double red_x, double red_y, double green_x,
1996 double green_y, double blue_x, double blue_y))
1997PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
1998 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
1999 double green_X, double green_Y, double green_Z, double blue_X,
2000 double blue_Y, double blue_Z))
2001PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
2002 png_inforp info_ptr, png_fixed_point int_white_x,
2003 png_fixed_point int_white_y, png_fixed_point int_red_x,
2004 png_fixed_point int_red_y, png_fixed_point int_green_x,
2005 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2006 png_fixed_point int_blue_y))
2007PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
2008 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
2009 png_fixed_point int_red_Z, png_fixed_point int_green_X,
2010 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
2011 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
2012 png_fixed_point int_blue_Z))
2013#endif
2014
2015#ifdef PNG_gAMA_SUPPORTED
2016PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
2017 png_const_inforp info_ptr, double *file_gamma))
2018PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2019 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2020 png_fixed_point *int_file_gamma))
2021#endif
2022
2023#ifdef PNG_gAMA_SUPPORTED
2024PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2025 png_inforp info_ptr, double file_gamma))
2026PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2027 png_inforp info_ptr, png_fixed_point int_file_gamma))
2028#endif
2029
2030#ifdef PNG_hIST_SUPPORTED
2031PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2032 png_inforp info_ptr, png_uint_16p *hist));
2033#endif
2034
2035#ifdef PNG_hIST_SUPPORTED
2036PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2037 png_inforp info_ptr, png_const_uint_16p hist));
2038#endif
2039
2040PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2041 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2042 int *bit_depth, int *color_type, int *interlace_method,
2043 int *compression_method, int *filter_method));
2044
2045PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2046 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2047 int color_type, int interlace_method, int compression_method,
2048 int filter_method));
2049
2050#ifdef PNG_oFFs_SUPPORTED
2051PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2052 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2053 int *unit_type));
2054#endif
2055
2056#ifdef PNG_oFFs_SUPPORTED
2057PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2058 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2059 int unit_type));
2060#endif
2061
2062#ifdef PNG_pCAL_SUPPORTED
2063PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2064 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2065 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2066 png_charpp *params));
2067#endif
2068
2069#ifdef PNG_pCAL_SUPPORTED
2070PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2071 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2072 int type, int nparams, png_const_charp units, png_charpp params));
2073#endif
2074
2075#ifdef PNG_pHYs_SUPPORTED
2076PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2077 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2078 int *unit_type));
2079#endif
2080
2081#ifdef PNG_pHYs_SUPPORTED
2082PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2083 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2084#endif
2085
2086PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2087 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2088
2089PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2090 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2091
2092#ifdef PNG_sBIT_SUPPORTED
2093PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2094 png_inforp info_ptr, png_color_8p *sig_bit));
2095#endif
2096
2097#ifdef PNG_sBIT_SUPPORTED
2098PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2099 png_inforp info_ptr, png_const_color_8p sig_bit));
2100#endif
2101
2102#ifdef PNG_sRGB_SUPPORTED
2103PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2104 png_const_inforp info_ptr, int *file_srgb_intent));
2105#endif
2106
2107#ifdef PNG_sRGB_SUPPORTED
2108PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2109 png_inforp info_ptr, int srgb_intent));
2110PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2111 png_inforp info_ptr, int srgb_intent));
2112#endif
2113
2114#ifdef PNG_iCCP_SUPPORTED
2115PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2116 png_inforp info_ptr, png_charpp name, int *compression_type,
2117 png_bytepp profile, png_uint_32 *proflen));
2118#endif
2119
2120#ifdef PNG_iCCP_SUPPORTED
2121PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2122 png_inforp info_ptr, png_const_charp name, int compression_type,
2123 png_const_bytep profile, png_uint_32 proflen));
2124#endif
2125
2126#ifdef PNG_sPLT_SUPPORTED
2127PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2128 png_inforp info_ptr, png_sPLT_tpp entries));
2129#endif
2130
2131#ifdef PNG_sPLT_SUPPORTED
2132PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2133 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2134#endif
2135
2136#ifdef PNG_TEXT_SUPPORTED
2137/* png_get_text also returns the number of text chunks in *num_text */
2138PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2139 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2140#endif
2141
2142/* Note while png_set_text() will accept a structure whose text,
2143 * language, and translated keywords are NULL pointers, the structure
2144 * returned by png_get_text will always contain regular
2145 * zero-terminated C strings. They might be empty strings but
2146 * they will never be NULL pointers.
2147 */
2148
2149#ifdef PNG_TEXT_SUPPORTED
2150PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2151 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2152#endif
2153
2154#ifdef PNG_tIME_SUPPORTED
2155PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2156 png_inforp info_ptr, png_timep *mod_time));
2157#endif
2158
2159#ifdef PNG_tIME_SUPPORTED
2160PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2161 png_inforp info_ptr, png_const_timep mod_time));
2162#endif
2163
2164#ifdef PNG_tRNS_SUPPORTED
2165PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2166 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2167 png_color_16p *trans_color));
2168#endif
2169
2170#ifdef PNG_tRNS_SUPPORTED
2171PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2172 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2173 png_const_color_16p trans_color));
2174#endif
2175
2176#ifdef PNG_sCAL_SUPPORTED
2177PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2178 png_const_inforp info_ptr, int *unit, double *width, double *height))
2179#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2180 defined(PNG_FLOATING_POINT_SUPPORTED)
2181/* NOTE: this API is currently implemented using floating point arithmetic,
2182 * consequently it can only be used on systems with floating point support.
2183 * In any case the range of values supported by png_fixed_point is small and it
2184 * is highly recommended that png_get_sCAL_s be used instead.
2185 */
2186PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2187 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2188 png_fixed_point *width, png_fixed_point *height))
2189#endif
2190PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2191 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2192 png_charpp swidth, png_charpp sheight));
2193
2194PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2195 png_inforp info_ptr, int unit, double width, double height))
2196PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2197 png_inforp info_ptr, int unit, png_fixed_point width,
2198 png_fixed_point height))
2199PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2200 png_inforp info_ptr, int unit,
2201 png_const_charp swidth, png_const_charp sheight));
2202#endif /* sCAL */
2203
2204#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2205/* Provide the default handling for all unknown chunks or, optionally, for
2206 * specific unknown chunks.
2207 *
2208 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2209 * ignored and the default was used, the per-chunk setting only had an effect on
2210 * write. If you wish to have chunk-specific handling on read in code that must
2211 * work on earlier versions you must use a user chunk callback to specify the
2212 * desired handling (keep or discard.)
2213 *
2214 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2215 * parameter is interpreted as follows:
2216 *
2217 * READ:
2218 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2219 * Known chunks: do normal libpng processing, do not keep the chunk (but
2220 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2221 * Unknown chunks: for a specific chunk use the global default, when used
2222 * as the default discard the chunk data.
2223 * PNG_HANDLE_CHUNK_NEVER:
2224 * Discard the chunk data.
2225 * PNG_HANDLE_CHUNK_IF_SAFE:
2226 * Keep the chunk data if the chunk is not critical else raise a chunk
2227 * error.
2228 * PNG_HANDLE_CHUNK_ALWAYS:
2229 * Keep the chunk data.
2230 *
2231 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2232 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2233 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2234 * it simply resets the behavior to the libpng default.
2235 *
2236 * INTERACTION WTIH USER CHUNK CALLBACKS:
2237 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2238 * callback and the callback returns 0; the chunk is then always stored *unless*
2239 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2240 * the global default is *not* used in this case. (In effect the per-chunk
2241 * value is incremented to at least IF_SAFE.)
2242 *
2243 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2244 * per-chunk defaults will be honored. If you want to preserve the current
2245 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2246 * as the default - if you don't do this libpng 1.6 will issue a warning.
2247 *
2248 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2249 * earlier simply return '1' (handled).
2250 *
2251 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2252 * If this is *not* set known chunks will always be handled by libpng and
2253 * will never be stored in the unknown chunk list. Known chunks listed to
2254 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2255 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2256 * by libpng, in addition critical chunks must either be processed by the
2257 * callback or saved.
2258 *
2259 * The IHDR and IEND chunks must not be listed. Because this turns off the
2260 * default handling for chunks that would otherwise be recognized the
2261 * behavior of libpng transformations may well become incorrect!
2262 *
2263 * WRITE:
2264 * When writing chunks the options only apply to the chunks specified by
2265 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2266 * required by png_set_ calls and will always write the core critical chunks
2267 * (as required for PLTE).
2268 *
2269 * Each chunk in the png_set_unknown_chunks list is looked up in the
2270 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2271 * interpreted as follows:
2272 *
2273 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2274 * Write safe-to-copy chunks and write other chunks if the global
2275 * default is set to _ALWAYS, otherwise don't write this chunk.
2276 * PNG_HANDLE_CHUNK_NEVER:
2277 * Do not write the chunk.
2278 * PNG_HANDLE_CHUNK_IF_SAFE:
2279 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2280 * PNG_HANDLE_CHUNK_ALWAYS:
2281 * Write the chunk.
2282 *
2283 * Note that the default behavior is effectively the opposite of the read case -
2284 * in read unknown chunks are not stored by default, in write they are written
2285 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2286 * - on write the safe-to-copy bit is checked, on read the critical bit is
2287 * checked and on read if the chunk is critical an error will be raised.
2288 *
2289 * num_chunks:
2290 * ===========
2291 * If num_chunks is positive, then the "keep" parameter specifies the manner
2292 * for handling only those chunks appearing in the chunk_list array,
2293 * otherwise the chunk list array is ignored.
2294 *
2295 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2296 * unknown chunks, as described above.
2297 *
2298 * If num_chunks is negative, then the "keep" parameter specifies the manner
2299 * for handling all unknown chunks plus all chunks recognized by libpng
2300 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2301 * be processed by libpng.
2302 */
2303PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2304 int keep, png_const_bytep chunk_list, int num_chunks));
2305
2306/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2307 * the result is therefore true (non-zero) if special handling is required,
2308 * false for the default handling.
2309 */
2310PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2311 png_const_bytep chunk_name));
2312#endif
2313
2314#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2315PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2316 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2317 int num_unknowns));
2318 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2319 * unknowns to the location currently stored in the png_struct. This is
2320 * invariably the wrong value on write. To fix this call the following API
2321 * for each chunk in the list with the correct location. If you know your
2322 * code won't be compiled on earlier versions you can rely on
2323 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2324 * the correct thing.
2325 */
2326
2327PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2328 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2329
2330PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2331 png_inforp info_ptr, png_unknown_chunkpp entries));
2332#endif
2333
2334/* Png_free_data() will turn off the "valid" flag for anything it frees.
2335 * If you need to turn it off for a chunk that your application has freed,
2336 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2337 */
2338PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2339 png_inforp info_ptr, int mask));
2340
2341#ifdef PNG_INFO_IMAGE_SUPPORTED
2342/* The "params" pointer is currently not used and is for future expansion. */
2343#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2344PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2345 int transforms, png_voidp params));
2346#endif
2347#ifdef PNG_WRITE_SUPPORTED
2348PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2349 int transforms, png_voidp params));
2350#endif
2351#endif
2352
2353PNG_EXPORT(180, png_const_charp, png_get_copyright,
2354 (png_const_structrp png_ptr));
2355PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2356 (png_const_structrp png_ptr));
2357PNG_EXPORT(182, png_const_charp, png_get_header_version,
2358 (png_const_structrp png_ptr));
2359PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2360 (png_const_structrp png_ptr));
2361
2362#ifdef PNG_MNG_FEATURES_SUPPORTED
2363PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2364 png_uint_32 mng_features_permitted));
2365#endif
2366
2367/* For use in png_set_keep_unknown, added to version 1.2.6 */
2368#define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2369#define PNG_HANDLE_CHUNK_NEVER 1
2370#define PNG_HANDLE_CHUNK_IF_SAFE 2
2371#define PNG_HANDLE_CHUNK_ALWAYS 3
2372#define PNG_HANDLE_CHUNK_LAST 4
2373
2374/* Strip the prepended error numbers ("#nnn ") from error and warning
2375 * messages before passing them to the error or warning handler.
2376 */
2377#ifdef PNG_ERROR_NUMBERS_SUPPORTED
2378PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2379 png_uint_32 strip_mode));
2380#endif
2381
2382/* Added in libpng-1.2.6 */
2383#ifdef PNG_SET_USER_LIMITS_SUPPORTED
2384PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2385 png_uint_32 user_width_max, png_uint_32 user_height_max));
2386PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2387 (png_const_structrp png_ptr));
2388PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2389 (png_const_structrp png_ptr));
2390/* Added in libpng-1.4.0 */
2391PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2392 png_uint_32 user_chunk_cache_max));
2393PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2394 (png_const_structrp png_ptr));
2395/* Added in libpng-1.4.1 */
2396PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2397 png_alloc_size_t user_chunk_cache_max));
2398PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2399 (png_const_structrp png_ptr));
2400#endif
2401
2402#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2403PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2404 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2405
2406PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2407 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2408
2409PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2410 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2411
2412PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2413 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2414#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2415PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2416 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2417#endif
2418
2419PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2420 png_const_inforp info_ptr))
2421#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2422PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2423 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2424#endif
2425
2426# ifdef PNG_pHYs_SUPPORTED
2427PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2428 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2429 int *unit_type));
2430# endif /* pHYs */
2431#endif /* INCH_CONVERSIONS */
2432
2433/* Added in libpng-1.4.0 */
2434#ifdef PNG_IO_STATE_SUPPORTED
2435PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2436
2437/* Removed from libpng 1.6; use png_get_io_chunk_type. */
2438PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2439 PNG_DEPRECATED)
2440
2441PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2442 (png_const_structrp png_ptr));
2443
2444/* The flags returned by png_get_io_state() are the following: */
2445# define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2446# define PNG_IO_READING 0x0001 /* currently reading */
2447# define PNG_IO_WRITING 0x0002 /* currently writing */
2448# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2449# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2450# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2451# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2452# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2453# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2454#endif /* IO_STATE */
2455
2456/* Interlace support. The following macros are always defined so that if
2457 * libpng interlace handling is turned off the macros may be used to handle
2458 * interlaced images within the application.
2459 */
2460#define PNG_INTERLACE_ADAM7_PASSES 7
2461
2462/* Two macros to return the first row and first column of the original,
2463 * full, image which appears in a given pass. 'pass' is in the range 0
2464 * to 6 and the result is in the range 0 to 7.
2465 */
2466#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2467#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2468
2469/* A macro to return the offset between pixels in the output row for a pair of
2470 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2471 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2472 * COL_OFFSET is from one column to the next, within a row.
2473 */
2474#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2475#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2476
2477/* Two macros to help evaluate the number of rows or columns in each
2478 * pass. This is expressed as a shift - effectively log2 of the number or
2479 * rows or columns in each 8x8 tile of the original image.
2480 */
2481#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2482#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2483
2484/* Hence two macros to determine the number of rows or columns in a given
2485 * pass of an image given its height or width. In fact these macros may
2486 * return non-zero even though the sub-image is empty, because the other
2487 * dimension may be empty for a small image.
2488 */
2489#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2490 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2491#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2492 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2493
2494/* For the reader row callbacks (both progressive and sequential) it is
2495 * necessary to find the row in the output image given a row in an interlaced
2496 * image, so two more macros:
2497 */
2498#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2499 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2500#define PNG_COL_FROM_PASS_COL(x_in, pass) \
2501 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2502
2503/* Two macros which return a boolean (0 or 1) saying whether the given row
2504 * or column is in a particular pass. These use a common utility macro that
2505 * returns a mask for a given pass - the offset 'off' selects the row or
2506 * column version. The mask has the appropriate bit set for each column in
2507 * the tile.
2508 */
2509#define PNG_PASS_MASK(pass,off) ( \
2510 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2511 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2512
2513#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2514 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2515#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2516 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2517
2518#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2519/* With these routines we avoid an integer divide, which will be slower on
2520 * most machines. However, it does take more operations than the corresponding
2521 * divide method, so it may be slower on a few RISC systems. There are two
2522 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2523 *
2524 * Note that the rounding factors are NOT supposed to be the same! 128 and
2525 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2526 * standard method.
2527 *
2528 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2529 */
2530
2531 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2532
2533# define png_composite(composite, fg, alpha, bg) \
2534 { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2535 * (png_uint_16)(alpha) \
2536 + (png_uint_16)(bg)*(png_uint_16)(255 \
2537 - (png_uint_16)(alpha)) + 128); \
2538 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); }
2539
2540# define png_composite_16(composite, fg, alpha, bg) \
2541 { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2542 * (png_uint_32)(alpha) \
2543 + (png_uint_32)(bg)*(65535 \
2544 - (png_uint_32)(alpha)) + 32768); \
2545 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); }
2546
2547#else /* Standard method using integer division */
2548
2549# define png_composite(composite, fg, alpha, bg) \
2550 (composite) = \
2551 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2552 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2553 127) / 255))
2554
2555# define png_composite_16(composite, fg, alpha, bg) \
2556 (composite) = \
2557 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2558 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2559 32767) / 65535))
2560#endif /* READ_COMPOSITE_NODIV */
2561
2562#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2563PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2564PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2565PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2566#endif
2567
2568PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2569 png_const_bytep buf));
2570/* No png_get_int_16 -- may be added if there's a real need for it. */
2571
2572/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2573#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2574PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2575#endif
2576#ifdef PNG_SAVE_INT_32_SUPPORTED
2577PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2578#endif
2579
2580/* Place a 16-bit number into a buffer in PNG byte order.
2581 * The parameter is declared unsigned int, not png_uint_16,
2582 * just to avoid potential problems on pre-ANSI C compilers.
2583 */
2584#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2585PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2586/* No png_save_int_16 -- may be added if there's a real need for it. */
2587#endif
2588
2589#ifdef PNG_USE_READ_MACROS
2590/* Inline macros to do direct reads of bytes from the input buffer.
2591 * The png_get_int_32() routine assumes we are using two's complement
2592 * format for negative values, which is almost certainly true.
2593 */
2594# define PNG_get_uint_32(buf) \
2595 (((png_uint_32)(*(buf)) << 24) + \
2596 ((png_uint_32)(*((buf) + 1)) << 16) + \
2597 ((png_uint_32)(*((buf) + 2)) << 8) + \
2598 ((png_uint_32)(*((buf) + 3))))
2599
2600 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2601 * function) incorrectly returned a value of type png_uint_32.
2602 */
2603# define PNG_get_uint_16(buf) \
2604 ((png_uint_16) \
2605 (((unsigned int)(*(buf)) << 8) + \
2606 ((unsigned int)(*((buf) + 1)))))
2607
2608# define PNG_get_int_32(buf) \
2609 ((png_int_32)((*(buf) & 0x80) \
2610 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2611 : (png_int_32)png_get_uint_32(buf)))
2612
2613 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2614 * but defining a macro name prefixed with PNG_PREFIX.
2615 */
2616# ifndef PNG_PREFIX
2617# define png_get_uint_32(buf) PNG_get_uint_32(buf)
2618# define png_get_uint_16(buf) PNG_get_uint_16(buf)
2619# define png_get_int_32(buf) PNG_get_int_32(buf)
2620# endif
2621#else
2622# ifdef PNG_PREFIX
2623 /* No macros; revert to the (redefined) function */
2624# define PNG_get_uint_32 (png_get_uint_32)
2625# define PNG_get_uint_16 (png_get_uint_16)
2626# define PNG_get_int_32 (png_get_int_32)
2627# endif
2628#endif
2629
2630#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2631PNG_EXPORT(242, void, png_set_check_for_invalid_index,
2632 (png_structrp png_ptr, int allowed));
2633# ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2634PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
2635 png_const_infop info_ptr));
2636# endif
2637#endif /* CHECK_FOR_INVALID_INDEX */
2638
2639/*******************************************************************************
2640 * Section 5: SIMPLIFIED API
2641 *******************************************************************************
2642 *
2643 * Please read the documentation in libpng-manual.txt (TODO: write said
2644 * documentation) if you don't understand what follows.
2645 *
2646 * The simplified API hides the details of both libpng and the PNG file format
2647 * itself. It allows PNG files to be read into a very limited number of
2648 * in-memory bitmap formats or to be written from the same formats. If these
2649 * formats do not accomodate your needs then you can, and should, use the more
2650 * sophisticated APIs above - these support a wide variety of in-memory formats
2651 * and a wide variety of sophisticated transformations to those formats as well
2652 * as a wide variety of APIs to manipulate ancillary information.
2653 *
2654 * To read a PNG file using the simplified API:
2655 *
2656 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2657 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2658 * (this is REQUIRED, your program may crash if you don't do it.)
2659 * 2) Call the appropriate png_image_begin_read... function.
2660 * 3) Set the png_image 'format' member to the required sample format.
2661 * 4) Allocate a buffer for the image and, if required, the color-map.
2662 * 5) Call png_image_finish_read to read the image and, if required, the
2663 * color-map into your buffers.
2664 *
2665 * There are no restrictions on the format of the PNG input itself; all valid
2666 * color types, bit depths, and interlace methods are acceptable, and the
2667 * input image is transformed as necessary to the requested in-memory format
2668 * during the png_image_finish_read() step. The only caveat is that if you
2669 * request a color-mapped image from a PNG that is full-color or makes
2670 * complex use of an alpha channel the transformation is extremely lossy and the
2671 * result may look terrible.
2672 *
2673 * To write a PNG file using the simplified API:
2674 *
2675 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2676 * 2) Initialize the members of the structure that describe the image, setting
2677 * the 'format' member to the format of the image samples.
2678 * 3) Call the appropriate png_image_write... function with a pointer to the
2679 * image and, if necessary, the color-map to write the PNG data.
2680 *
2681 * png_image is a structure that describes the in-memory format of an image
2682 * when it is being read or defines the in-memory format of an image that you
2683 * need to write:
2684 */
2685#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2686 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2687
2688#define PNG_IMAGE_VERSION 1
2689
2690typedef struct png_control *png_controlp;
2691typedef struct
2692{
2693 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2694 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2695 png_uint_32 width; /* Image width in pixels (columns) */
2696 png_uint_32 height; /* Image height in pixels (rows) */
2697 png_uint_32 format; /* Image format as defined below */
2698 png_uint_32 flags; /* A bit mask containing informational flags */
2699 png_uint_32 colormap_entries;
2700 /* Number of entries in the color-map */
2701
2702 /* In the event of an error or warning the following field will be set to a
2703 * non-zero value and the 'message' field will contain a '\0' terminated
2704 * string with the libpng error or warning message. If both warnings and
2705 * an error were encountered, only the error is recorded. If there
2706 * are multiple warnings, only the first one is recorded.
2707 *
2708 * The upper 30 bits of this value are reserved, the low two bits contain
2709 * a value as follows:
2710 */
2711# define PNG_IMAGE_WARNING 1
2712# define PNG_IMAGE_ERROR 2
2713 /*
2714 * The result is a two-bit code such that a value more than 1 indicates
2715 * a failure in the API just called:
2716 *
2717 * 0 - no warning or error
2718 * 1 - warning
2719 * 2 - error
2720 * 3 - error preceded by warning
2721 */
2722# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2723
2724 png_uint_32 warning_or_error;
2725
2726 char message[64];
2727} png_image, *png_imagep;
2728
2729/* The samples of the image have one to four channels whose components have
2730 * original values in the range 0 to 1.0:
2731 *
2732 * 1: A single gray or luminance channel (G).
2733 * 2: A gray/luminance channel and an alpha channel (GA).
2734 * 3: Three red, green, blue color channels (RGB).
2735 * 4: Three color channels and an alpha channel (RGBA).
2736 *
2737 * The components are encoded in one of two ways:
2738 *
2739 * a) As a small integer, value 0..255, contained in a single byte. For the
2740 * alpha channel the original value is simply value/255. For the color or
2741 * luminance channels the value is encoded according to the sRGB specification
2742 * and matches the 8-bit format expected by typical display devices.
2743 *
2744 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2745 * channel and are suitable for passing to color management software.
2746 *
2747 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2748 * channels can be converted to the original value by dividing by 65535; all
2749 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2750 * the sRGB specification. This encoding is identified by the
2751 * PNG_FORMAT_FLAG_LINEAR flag below.
2752 *
2753 * When the simplified API needs to convert between sRGB and linear colorspaces,
2754 * the actual sRGB transfer curve defined in the sRGB specification (see the
2755 * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
2756 * approximation used elsewhere in libpng.
2757 *
2758 * When an alpha channel is present it is expected to denote pixel coverage
2759 * of the color or luminance channels and is returned as an associated alpha
2760 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2761 * value.
2762 *
2763 * The samples are either contained directly in the image data, between 1 and 8
2764 * bytes per pixel according to the encoding, or are held in a color-map indexed
2765 * by bytes in the image data. In the case of a color-map the color-map entries
2766 * are individual samples, encoded as above, and the image data has one byte per
2767 * pixel to select the relevant sample from the color-map.
2768 */
2769
2770/* PNG_FORMAT_*
2771 *
2772 * #defines to be used in png_image::format. Each #define identifies a
2773 * particular layout of sample data and, if present, alpha values. There are
2774 * separate defines for each of the two component encodings.
2775 *
2776 * A format is built up using single bit flag values. All combinations are
2777 * valid. Formats can be built up from the flag values or you can use one of
2778 * the predefined values below. When testing formats always use the FORMAT_FLAG
2779 * macros to test for individual features - future versions of the library may
2780 * add new flags.
2781 *
2782 * When reading or writing color-mapped images the format should be set to the
2783 * format of the entries in the color-map then png_image_{read,write}_colormap
2784 * called to read or write the color-map and set the format correctly for the
2785 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2786 *
2787 * NOTE: libpng can be built with particular features disabled. If you see
2788 * compiler errors because the definition of one of the following flags has been
2789 * compiled out it is because libpng does not have the required support. It is
2790 * possible, however, for the libpng configuration to enable the format on just
2791 * read or just write; in that case you may see an error at run time. You can
2792 * guard against this by checking for the definition of the appropriate
2793 * "_SUPPORTED" macro, one of:
2794 *
2795 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2796 */
2797#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2798#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2799#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2800#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2801
2802#ifdef PNG_FORMAT_BGR_SUPPORTED
2803# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2804#endif
2805
2806#ifdef PNG_FORMAT_AFIRST_SUPPORTED
2807# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2808#endif
2809
2810/* Commonly used formats have predefined macros.
2811 *
2812 * First the single byte (sRGB) formats:
2813 */
2814#define PNG_FORMAT_GRAY 0
2815#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2816#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2817#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2818#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2819#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2820#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2821#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2822#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2823
2824/* Then the linear 2-byte formats. When naming these "Y" is used to
2825 * indicate a luminance (gray) channel.
2826 */
2827#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2828#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2829#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2830#define PNG_FORMAT_LINEAR_RGB_ALPHA \
2831 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2832
2833/* With color-mapped formats the image data is one byte for each pixel, the byte
2834 * is an index into the color-map which is formatted as above. To obtain a
2835 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2836 * to one of the above definitions, or you can use one of the definitions below.
2837 */
2838#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2839#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2840#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2841#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2842#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2843#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2844
2845/* PNG_IMAGE macros
2846 *
2847 * These are convenience macros to derive information from a png_image
2848 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2849 * actual image sample values - either the entries in the color-map or the
2850 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2851 * for the pixels and will always return 1 for color-mapped formats. The
2852 * remaining macros return information about the rows in the image and the
2853 * complete image.
2854 *
2855 * NOTE: All the macros that take a png_image::format parameter are compile time
2856 * constants if the format parameter is, itself, a constant. Therefore these
2857 * macros can be used in array declarations and case labels where required.
2858 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2859 * they can be used in #if tests.
2860 *
2861 * First the information about the samples.
2862 */
2863#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2864 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2865 /* Return the total number of channels in a given format: 1..4 */
2866
2867#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2868 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2869 /* Return the size in bytes of a single component of a pixel or color-map
2870 * entry (as appropriate) in the image: 1 or 2.
2871 */
2872
2873#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2874 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2875 /* This is the size of the sample data for one sample. If the image is
2876 * color-mapped it is the size of one color-map entry (and image pixels are
2877 * one byte in size), otherwise it is the size of one image pixel.
2878 */
2879
2880#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2881 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2882 /* The maximum size of the color-map required by the format expressed in a
2883 * count of components. This can be used to compile-time allocate a
2884 * color-map:
2885 *
2886 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2887 *
2888 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2889 *
2890 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2891 * information from one of the png_image_begin_read_ APIs and dynamically
2892 * allocate the required memory.
2893 */
2894
2895/* Corresponding information about the pixels */
2896#define PNG_IMAGE_PIXEL_(test,fmt)\
2897 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2898
2899#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2900 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2901 /* The number of separate channels (components) in a pixel; 1 for a
2902 * color-mapped image.
2903 */
2904
2905#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2906 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2907 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2908 * image.
2909 */
2910
2911#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2912 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2913
2914/* Information about the whole row, or whole image */
2915#define PNG_IMAGE_ROW_STRIDE(image)\
2916 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2917 /* Return the total number of components in a single row of the image; this
2918 * is the minimum 'row stride', the minimum count of components between each
2919 * row. For a color-mapped image this is the minimum number of bytes in a
2920 * row.
2921 *
2922 * WARNING: this macro overflows for some images with more than one component
2923 * and very large image widths. libpng will refuse to process an image where
2924 * this macro would overflow.
2925 */
2926
2927#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2928 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2929 /* Return the size, in bytes, of an image buffer given a png_image and a row
2930 * stride - the number of components to leave space for in each row.
2931 *
2932 * WARNING: this macro overflows a 32-bit integer for some large PNG images,
2933 * libpng will refuse to process an image where such an overflow would occur.
2934 */
2935
2936#define PNG_IMAGE_SIZE(image)\
2937 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2938 /* Return the size, in bytes, of the image in memory given just a png_image;
2939 * the row stride is the minimum stride required for the image.
2940 */
2941
2942#define PNG_IMAGE_COLORMAP_SIZE(image)\
2943 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2944 /* Return the size, in bytes, of the color-map of this image. If the image
2945 * format is not a color-map format this will return a size sufficient for
2946 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2947 * you don't want to allocate a color-map in this case.
2948 */
2949
2950/* PNG_IMAGE_FLAG_*
2951 *
2952 * Flags containing additional information about the image are held in the
2953 * 'flags' field of png_image.
2954 */
2955#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2956 /* This indicates the the RGB values of the in-memory bitmap do not
2957 * correspond to the red, green and blue end-points defined by sRGB.
2958 */
2959
2960#define PNG_IMAGE_FLAG_FAST 0x02
2961 /* On write emphasise speed over compression; the resultant PNG file will be
2962 * larger but will be produced significantly faster, particular for large
2963 * images. Do not use this option for images which will be distributed, only
2964 * used it when producing intermediate files that will be read back in
2965 * repeatedly. For a typical 24-bit image the option will double the read
2966 * speed at the cost of increasing the image size by 25%, however for many
2967 * more compressible images the PNG file can be 10 times larger with only a
2968 * slight speed gain.
2969 */
2970
2971#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
2972 /* On read if the image is a 16-bit per component image and there is no gAMA
2973 * or sRGB chunk assume that the components are sRGB encoded. Notice that
2974 * images output by the simplified API always have gamma information; setting
2975 * this flag only affects the interpretation of 16-bit images from an
2976 * external source. It is recommended that the application expose this flag
2977 * to the user; the user can normally easily recognize the difference between
2978 * linear and sRGB encoding. This flag has no effect on write - the data
2979 * passed to the write APIs must have the correct encoding (as defined
2980 * above.)
2981 *
2982 * If the flag is not set (the default) input 16-bit per component data is
2983 * assumed to be linear.
2984 *
2985 * NOTE: the flag can only be set after the png_image_begin_read_ call,
2986 * because that call initializes the 'flags' field.
2987 */
2988
2989#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
2990/* READ APIs
2991 * ---------
2992 *
2993 * The png_image passed to the read APIs must have been initialized by setting
2994 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
2995 */
2996#ifdef PNG_STDIO_SUPPORTED
2997PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
2998 const char *file_name));
2999 /* The named file is opened for read and the image header is filled in
3000 * from the PNG header in the file.
3001 */
3002
3003PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
3004 FILE* file));
3005 /* The PNG header is read from the stdio FILE object. */
3006#endif /* STDIO */
3007
3008PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
3009 png_const_voidp memory, png_size_t size));
3010 /* The PNG header is read from the given memory buffer. */
3011
3012PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
3013 png_const_colorp background, void *buffer, png_int_32 row_stride,
3014 void *colormap));
3015 /* Finish reading the image into the supplied buffer and clean up the
3016 * png_image structure.
3017 *
3018 * row_stride is the step, in byte or 2-byte units as appropriate,
3019 * between adjacent rows. A positive stride indicates that the top-most row
3020 * is first in the buffer - the normal top-down arrangement. A negative
3021 * stride indicates that the bottom-most row is first in the buffer.
3022 *
3023 * background need only be supplied if an alpha channel must be removed from
3024 * a png_byte format and the removal is to be done by compositing on a solid
3025 * color; otherwise it may be NULL and any composition will be done directly
3026 * onto the buffer. The value is an sRGB color to use for the background,
3027 * for grayscale output the green channel is used.
3028 *
3029 * background must be supplied when an alpha channel must be removed from a
3030 * single byte color-mapped output format, in other words if:
3031 *
3032 * 1) The original format from png_image_begin_read_from_* had
3033 * PNG_FORMAT_FLAG_ALPHA set.
3034 * 2) The format set by the application does not.
3035 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3036 * PNG_FORMAT_FLAG_LINEAR *not* set.
3037 *
3038 * For linear output removing the alpha channel is always done by compositing
3039 * on black and background is ignored.
3040 *
3041 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3042 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3043 * image->colormap_entries will be updated to the actual number of entries
3044 * written to the colormap; this may be less than the original value.
3045 */
3046
3047PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3048 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3049 * NULL. May be called at any time after the structure is initialized.
3050 */
3051#endif /* SIMPLIFIED_READ */
3052
3053#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3054/* WRITE APIS
3055 * ----------
3056 * For write you must initialize a png_image structure to describe the image to
3057 * be written. To do this use memset to set the whole structure to 0 then
3058 * initialize fields describing your image.
3059 *
3060 * version: must be set to PNG_IMAGE_VERSION
3061 * opaque: must be initialized to NULL
3062 * width: image width in pixels
3063 * height: image height in rows
3064 * format: the format of the data (image and color-map) you wish to write
3065 * flags: set to 0 unless one of the defined flags applies; set
3066 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3067 * values do not correspond to the colors in sRGB.
3068 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3069 */
3070#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3071PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3072 const char *file, int convert_to_8bit, const void *buffer,
3073 png_int_32 row_stride, const void *colormap));
3074 /* Write the image to the named file. */
3075
3076PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3077 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3078 const void *colormap));
3079 /* Write the image to the given (FILE*). */
3080#endif /* SIMPLIFIED_WRITE_STDIO */
3081
3082/* With all write APIs if image is in one of the linear formats with 16-bit
3083 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3084 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3085 * encoded PNG file is written.
3086 *
3087 * With color-mapped data formats the colormap parameter point to a color-map
3088 * with at least image->colormap_entries encoded in the specified format. If
3089 * the format is linear the written PNG color-map will be converted to sRGB
3090 * regardless of the convert_to_8_bit flag.
3091 *
3092 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3093 * from one row to the next in component sized units (1 or 2 bytes) and if
3094 * negative indicates a bottom-up row layout in the buffer. If row_stride is
3095 * zero, libpng will calculate it for you from the image width and number of
3096 * channels.
3097 *
3098 * Note that the write API does not support interlacing, sub-8-bit pixels or
3099 * most ancillary chunks. If you need to write text chunks (e.g. for copyright
3100 * notices) you need to use one of the other APIs.
3101 */
3102
3103PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
3104 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
3105 const void *buffer, png_int_32 row_stride, const void *colormap));
3106 /* Write the image to the given memory buffer. The function both writes the
3107 * whole PNG data stream to *memory and updates *memory_bytes with the count
3108 * of bytes written.
3109 *
3110 * 'memory' may be NULL. In this case *memory_bytes is not read however on
3111 * success the number of bytes which would have been written will still be
3112 * stored in *memory_bytes. On failure *memory_bytes will contain 0.
3113 *
3114 * If 'memory' is not NULL it must point to memory[*memory_bytes] of
3115 * writeable memory.
3116 *
3117 * If the function returns success memory[*memory_bytes] (if 'memory' is not
3118 * NULL) contains the written PNG data. *memory_bytes will always be less
3119 * than or equal to the original value.
3120 *
3121 * If the function returns false and *memory_bytes was not changed an error
3122 * occured during write. If *memory_bytes was changed, or is not 0 if
3123 * 'memory' was NULL, the write would have succeeded but for the memory
3124 * buffer being too small. *memory_bytes contains the required number of
3125 * bytes and will be bigger that the original value.
3126 */
3127
3128#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
3129 row_stride, colormap)\
3130 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
3131 row_stride, colormap)
3132 /* Return the amount of memory in 'size' required to compress this image.
3133 * The png_image structure 'image' must be filled in as in the above
3134 * function and must not be changed before the actual write call, the buffer
3135 * and all other parameters must also be identical to that in the final
3136 * write call. The 'size' variable need not be initialized.
3137 *
3138 * NOTE: the macro returns true/false, if false is returned 'size' will be
3139 * set to zero and the write failed and probably will fail if tried again.
3140 */
3141
3142/* You can pre-allocate the buffer by making sure it is of sufficient size
3143 * regardless of the amount of compression achieved. The buffer size will
3144 * always be bigger than the original image and it will never be filled. The
3145 * following macros are provided to assist in allocating the buffer.
3146 */
3147#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
3148 /* The number of uncompressed bytes in the PNG byte encoding of the image;
3149 * uncompressing the PNG IDAT data will give this number of bytes.
3150 *
3151 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
3152 * macro can because of the extra bytes used in the PNG byte encoding. You
3153 * need to avoid this macro if your image size approaches 2^30 in width or
3154 * height. The same goes for the remainder of these macros; they all produce
3155 * bigger numbers than the actual in-memory image size.
3156 */
3157#ifndef PNG_ZLIB_MAX_SIZE
3158# define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
3159 /* An upper bound on the number of compressed bytes given 'b' uncompressed
3160 * bytes. This is based on deflateBounds() in zlib; different
3161 * implementations of zlib compression may conceivably produce more data so
3162 * if your zlib implementation is not zlib itself redefine this macro
3163 * appropriately.
3164 */
3165#endif
3166
3167#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
3168 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
3169 /* An upper bound on the size of the data in the PNG IDAT chunks. */
3170
3171#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
3172 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
3173 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
3174 12U+3U*(image).colormap_entries/*PLTE data*/+\
3175 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
3176 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
3177 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
3178 /* A helper for the following macro; if your compiler cannot handle the
3179 * following macro use this one with the result of
3180 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
3181 * compilers should handle this just fine.)
3182 */
3183
3184#define PNG_IMAGE_PNG_SIZE_MAX(image)\
3185 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
3186 /* An upper bound on the total length of the PNG data stream for 'image'.
3187 * The result is of type png_alloc_size_t, on 32-bit systems this may
3188 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
3189 * run out of buffer space but return a corrected size which should work.
3190 */
3191#endif /* SIMPLIFIED_WRITE */
3192/*******************************************************************************
3193 * END OF SIMPLIFIED API
3194 ******************************************************************************/
3195#endif /* SIMPLIFIED_{READ|WRITE} */
3196
3197/*******************************************************************************
3198 * Section 6: IMPLEMENTATION OPTIONS
3199 *******************************************************************************
3200 *
3201 * Support for arbitrary implementation-specific optimizations. The API allows
3202 * particular options to be turned on or off. 'Option' is the number of the
3203 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3204 * by the PNG_OPTION_ defines below.
3205 *
3206 * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
3207 * are detected at run time, however sometimes it may be impossible
3208 * to do this in user mode, in which case it is necessary to discover
3209 * the capabilities in an OS specific way. Such capabilities are
3210 * listed here when libpng has support for them and must be turned
3211 * ON by the application if present.
3212 *
3213 * SOFTWARE: sometimes software optimizations actually result in performance
3214 * decrease on some architectures or systems, or with some sets of
3215 * PNG images. 'Software' options allow such optimizations to be
3216 * selected at run time.
3217 */
3218#ifdef PNG_SET_OPTION_SUPPORTED
3219#ifdef PNG_ARM_NEON_API_SUPPORTED
3220# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3221#endif
3222#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3223#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3224#define PNG_OPTION_NEXT 6 /* Next option - numbers must be even */
3225
3226/* Return values: NOTE: there are four values and 'off' is *not* zero */
3227#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3228#define PNG_OPTION_INVALID 1 /* Option number out of range */
3229#define PNG_OPTION_OFF 2
3230#define PNG_OPTION_ON 3
3231
3232PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3233 int onoff));
3234#endif /* SET_OPTION */
3235
3236/*******************************************************************************
3237 * END OF HARDWARE AND SOFTWARE OPTIONS
3238 ******************************************************************************/
3239
3240/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3241 * defs, and in scripts/symbols.def.
3242 */
3243
3244/* The last ordinal number (this is the *last* one already used; the next
3245 * one to use is one more than this.)
3246 */
3247#ifdef PNG_EXPORT_LAST_ORDINAL
3248 PNG_EXPORT_LAST_ORDINAL(245);
3249#endif
3250
3251#ifdef __cplusplus
3252}
3253#endif
3254
3255#endif /* PNG_VERSION_INFO_ONLY */
3256/* Do not put anything past this line */
3257#endif /* PNG_H */
3258