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1
2/* png.h - header file for PNG reference library
3 *
4 * libpng version 1.6.37 - April 14, 2019
5 *
6 * Copyright (c) 2018-2019 Cosmin Truta
7 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
8 * Copyright (c) 1996-1997 Andreas Dilger
9 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
10 *
11 * This code is released under the libpng license. (See LICENSE, below.)
12 *
13 * Authors and maintainers:
14 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
15 * libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
16 * libpng versions 0.97, January 1998, through 1.6.35, July 2018:
17 * Glenn Randers-Pehrson
18 * libpng versions 1.6.36, December 2018, through 1.6.37, April 2019:
19 * Cosmin Truta
20 * See also "Contributing Authors", below.
21 */
22
23/*
24 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
25 * =========================================
26 *
27 * PNG Reference Library License version 2
28 * ---------------------------------------
29 *
30 * * Copyright (c) 1995-2019 The PNG Reference Library Authors.
31 * * Copyright (c) 2018-2019 Cosmin Truta.
32 * * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
33 * * Copyright (c) 1996-1997 Andreas Dilger.
34 * * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
35 *
36 * The software is supplied "as is", without warranty of any kind,
37 * express or implied, including, without limitation, the warranties
38 * of merchantability, fitness for a particular purpose, title, and
39 * non-infringement. In no event shall the Copyright owners, or
40 * anyone distributing the software, be liable for any damages or
41 * other liability, whether in contract, tort or otherwise, arising
42 * from, out of, or in connection with the software, or the use or
43 * other dealings in the software, even if advised of the possibility
44 * of such damage.
45 *
46 * Permission is hereby granted to use, copy, modify, and distribute
47 * this software, or portions hereof, for any purpose, without fee,
48 * subject to the following restrictions:
49 *
50 * 1. The origin of this software must not be misrepresented; you
51 * must not claim that you wrote the original software. If you
52 * use this software in a product, an acknowledgment in the product
53 * documentation would be appreciated, but is not required.
54 *
55 * 2. Altered source versions must be plainly marked as such, and must
56 * not be misrepresented as being the original software.
57 *
58 * 3. This Copyright notice may not be removed or altered from any
59 * source or altered source distribution.
60 *
61 *
62 * PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
63 * -----------------------------------------------------------------------
64 *
65 * libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are
66 * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
67 * derived from libpng-1.0.6, and are distributed according to the same
68 * disclaimer and license as libpng-1.0.6 with the following individuals
69 * added to the list of Contributing Authors:
70 *
71 * Simon-Pierre Cadieux
72 * Eric S. Raymond
73 * Mans Rullgard
74 * Cosmin Truta
75 * Gilles Vollant
76 * James Yu
77 * Mandar Sahastrabuddhe
78 * Google Inc.
79 * Vadim Barkov
80 *
81 * and with the following additions to the disclaimer:
82 *
83 * There is no warranty against interference with your enjoyment of
84 * the library or against infringement. There is no warranty that our
85 * efforts or the library will fulfill any of your particular purposes
86 * or needs. This library is provided with all faults, and the entire
87 * risk of satisfactory quality, performance, accuracy, and effort is
88 * with the user.
89 *
90 * Some files in the "contrib" directory and some configure-generated
91 * files that are distributed with libpng have other copyright owners, and
92 * are released under other open source licenses.
93 *
94 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
95 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
96 * libpng-0.96, and are distributed according to the same disclaimer and
97 * license as libpng-0.96, with the following individuals added to the
98 * list of Contributing Authors:
99 *
100 * Tom Lane
101 * Glenn Randers-Pehrson
102 * Willem van Schaik
103 *
104 * libpng versions 0.89, June 1996, through 0.96, May 1997, are
105 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
106 * and are distributed according to the same disclaimer and license as
107 * libpng-0.88, with the following individuals added to the list of
108 * Contributing Authors:
109 *
110 * John Bowler
111 * Kevin Bracey
112 * Sam Bushell
113 * Magnus Holmgren
114 * Greg Roelofs
115 * Tom Tanner
116 *
117 * Some files in the "scripts" directory have other copyright owners,
118 * but are released under this license.
119 *
120 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
121 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
122 *
123 * For the purposes of this copyright and license, "Contributing Authors"
124 * is defined as the following set of individuals:
125 *
126 * Andreas Dilger
127 * Dave Martindale
128 * Guy Eric Schalnat
129 * Paul Schmidt
130 * Tim Wegner
131 *
132 * The PNG Reference Library is supplied "AS IS". The Contributing
133 * Authors and Group 42, Inc. disclaim all warranties, expressed or
134 * implied, including, without limitation, the warranties of
135 * merchantability and of fitness for any purpose. The Contributing
136 * Authors and Group 42, Inc. assume no liability for direct, indirect,
137 * incidental, special, exemplary, or consequential damages, which may
138 * result from the use of the PNG Reference Library, even if advised of
139 * the possibility of such damage.
140 *
141 * Permission is hereby granted to use, copy, modify, and distribute this
142 * source code, or portions hereof, for any purpose, without fee, subject
143 * to the following restrictions:
144 *
145 * 1. The origin of this source code must not be misrepresented.
146 *
147 * 2. Altered versions must be plainly marked as such and must not
148 * be misrepresented as being the original source.
149 *
150 * 3. This Copyright notice may not be removed or altered from any
151 * source or altered source distribution.
152 *
153 * The Contributing Authors and Group 42, Inc. specifically permit,
154 * without fee, and encourage the use of this source code as a component
155 * to supporting the PNG file format in commercial products. If you use
156 * this source code in a product, acknowledgment is not required but would
157 * be appreciated.
158 *
159 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
160 *
161 * TRADEMARK
162 * =========
163 *
164 * The name "libpng" has not been registered by the Copyright owners
165 * as a trademark in any jurisdiction. However, because libpng has
166 * been distributed and maintained world-wide, continually since 1995,
167 * the Copyright owners claim "common-law trademark protection" in any
168 * jurisdiction where common-law trademark is recognized.
169 */
170
171/*
172 * A "png_get_copyright" function is available, for convenient use in "about"
173 * boxes and the like:
174 *
175 * printf("%s", png_get_copyright(NULL));
176 *
177 * Also, the PNG logo (in PNG format, of course) is supplied in the
178 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
179 */
180
181/*
182 * The contributing authors would like to thank all those who helped
183 * with testing, bug fixes, and patience. This wouldn't have been
184 * possible without all of you.
185 *
186 * Thanks to Frank J. T. Wojcik for helping with the documentation.
187 */
188
189/* Note about libpng version numbers:
190 *
191 * Due to various miscommunications, unforeseen code incompatibilities
192 * and occasional factors outside the authors' control, version numbering
193 * on the library has not always been consistent and straightforward.
194 * The following table summarizes matters since version 0.89c, which was
195 * the first widely used release:
196 *
197 * source png.h png.h shared-lib
198 * version string int version
199 * ------- ------ ----- ----------
200 * 0.89c "1.0 beta 3" 0.89 89 1.0.89
201 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
202 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
203 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
204 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
205 * 0.97c 0.97 97 2.0.97
206 * 0.98 0.98 98 2.0.98
207 * 0.99 0.99 98 2.0.99
208 * 0.99a-m 0.99 99 2.0.99
209 * 1.00 1.00 100 2.1.0 [100 should be 10000]
210 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
211 * 1.0.1 png.h string is 10001 2.1.0
212 * 1.0.1a-e identical to the 10002 from here on, the shared library
213 * 1.0.2 source version) 10002 is 2.V where V is the source code
214 * 1.0.2a-b 10003 version, except as noted.
215 * 1.0.3 10003
216 * 1.0.3a-d 10004
217 * 1.0.4 10004
218 * 1.0.4a-f 10005
219 * 1.0.5 (+ 2 patches) 10005
220 * 1.0.5a-d 10006
221 * 1.0.5e-r 10100 (not source compatible)
222 * 1.0.5s-v 10006 (not binary compatible)
223 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
224 * 1.0.6d-f 10007 (still binary incompatible)
225 * 1.0.6g 10007
226 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
227 * 1.0.6i 10007 10.6i
228 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
229 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
230 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
231 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
232 * 1.0.7 1 10007 (still compatible)
233 * ...
234 * 1.0.69 10 10069 10.so.0.69[.0]
235 * ...
236 * 1.2.59 13 10259 12.so.0.59[.0]
237 * ...
238 * 1.4.20 14 10420 14.so.0.20[.0]
239 * ...
240 * 1.5.30 15 10530 15.so.15.30[.0]
241 * ...
242 * 1.6.37 16 10637 16.so.16.37[.0]
243 *
244 * Henceforth the source version will match the shared-library major and
245 * minor numbers; the shared-library major version number will be used for
246 * changes in backward compatibility, as it is intended.
247 * The PNG_LIBPNG_VER macro, which is not used within libpng but is
248 * available for applications, is an unsigned integer of the form XYYZZ
249 * corresponding to the source version X.Y.Z (leading zeros in Y and Z).
250 * Beta versions were given the previous public release number plus a
251 * letter, until version 1.0.6j; from then on they were given the upcoming
252 * public release number plus "betaNN" or "rcNN".
253 *
254 * Binary incompatibility exists only when applications make direct access
255 * to the info_ptr or png_ptr members through png.h, and the compiled
256 * application is loaded with a different version of the library.
257 *
258 * DLLNUM will change each time there are forward or backward changes
259 * in binary compatibility (e.g., when a new feature is added).
260 *
261 * See libpng.txt or libpng.3 for more information. The PNG specification
262 * is available as a W3C Recommendation and as an ISO/IEC Standard; see
263 * <https://www.w3.org/TR/2003/REC-PNG-20031110/>
264 */
265
266#ifndef PNG_H
267#define PNG_H
268
269/* This is not the place to learn how to use libpng. The file libpng-manual.txt
270 * describes how to use libpng, and the file example.c summarizes it
271 * with some code on which to build. This file is useful for looking
272 * at the actual function definitions and structure components. If that
273 * file has been stripped from your copy of libpng, you can find it at
274 * <http://www.libpng.org/pub/png/libpng-manual.txt>
275 *
276 * If you just need to read a PNG file and don't want to read the documentation
277 * skip to the end of this file and read the section entitled 'simplified API'.
278 */
279
280/* Version information for png.h - this should match the version in png.c */
281#define PNG_LIBPNG_VER_STRING "1.6.37"
282#define PNG_HEADER_VERSION_STRING " libpng version 1.6.37 - April 14, 2019\n"
283
284#define PNG_LIBPNG_VER_SONUM 16
285#define PNG_LIBPNG_VER_DLLNUM 16
286
287/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
288#define PNG_LIBPNG_VER_MAJOR 1
289#define PNG_LIBPNG_VER_MINOR 6
290#define PNG_LIBPNG_VER_RELEASE 37
291
292/* This should be zero for a public release, or non-zero for a
293 * development version. [Deprecated]
294 */
295#define PNG_LIBPNG_VER_BUILD 0
296
297/* Release Status */
298#define PNG_LIBPNG_BUILD_ALPHA 1
299#define PNG_LIBPNG_BUILD_BETA 2
300#define PNG_LIBPNG_BUILD_RC 3
301#define PNG_LIBPNG_BUILD_STABLE 4
302#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
303
304/* Release-Specific Flags */
305#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
306 PNG_LIBPNG_BUILD_STABLE only */
307#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
308 PNG_LIBPNG_BUILD_SPECIAL */
309#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
310 PNG_LIBPNG_BUILD_PRIVATE */
311
312#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
313
314/* Careful here. At one time, Guy wanted to use 082, but that
315 * would be octal. We must not include leading zeros.
316 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here
317 * (only version 1.0.0 was mis-numbered 100 instead of 10000).
318 * From version 1.0.1 it is:
319 * XXYYZZ, where XX=major, YY=minor, ZZ=release
320 */
321#define PNG_LIBPNG_VER 10637 /* 1.6.37 */
322
323/* Library configuration: these options cannot be changed after
324 * the library has been built.
325 */
326#ifndef PNGLCONF_H
327/* If pnglibconf.h is missing, you can
328 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
329 */
330# include "pnglibconf.h"
331#endif
332
333#ifndef PNG_VERSION_INFO_ONLY
334/* Machine specific configuration. */
335# include "pngconf.h"
336#endif
337
338/*
339 * Added at libpng-1.2.8
340 *
341 * Ref MSDN: Private as priority over Special
342 * VS_FF_PRIVATEBUILD File *was not* built using standard release
343 * procedures. If this value is given, the StringFileInfo block must
344 * contain a PrivateBuild string.
345 *
346 * VS_FF_SPECIALBUILD File *was* built by the original company using
347 * standard release procedures but is a variation of the standard
348 * file of the same version number. If this value is given, the
349 * StringFileInfo block must contain a SpecialBuild string.
350 */
351
352#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
353# define PNG_LIBPNG_BUILD_TYPE \
354 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
355#else
356# ifdef PNG_LIBPNG_SPECIALBUILD
357# define PNG_LIBPNG_BUILD_TYPE \
358 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
359# else
360# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
361# endif
362#endif
363
364#ifndef PNG_VERSION_INFO_ONLY
365
366/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
367#ifdef __cplusplus
368extern "C" {
369#endif /* __cplusplus */
370
371/* Version information for C files, stored in png.c. This had better match
372 * the version above.
373 */
374#define png_libpng_ver png_get_header_ver(NULL)
375
376/* This file is arranged in several sections:
377 *
378 * 1. [omitted]
379 * 2. Any configuration options that can be specified by for the application
380 * code when it is built. (Build time configuration is in pnglibconf.h)
381 * 3. Type definitions (base types are defined in pngconf.h), structure
382 * definitions.
383 * 4. Exported library functions.
384 * 5. Simplified API.
385 * 6. Implementation options.
386 *
387 * The library source code has additional files (principally pngpriv.h) that
388 * allow configuration of the library.
389 */
390
391/* Section 1: [omitted] */
392
393/* Section 2: run time configuration
394 * See pnglibconf.h for build time configuration
395 *
396 * Run time configuration allows the application to choose between
397 * implementations of certain arithmetic APIs. The default is set
398 * at build time and recorded in pnglibconf.h, but it is safe to
399 * override these (and only these) settings. Note that this won't
400 * change what the library does, only application code, and the
401 * settings can (and probably should) be made on a per-file basis
402 * by setting the #defines before including png.h
403 *
404 * Use macros to read integers from PNG data or use the exported
405 * functions?
406 * PNG_USE_READ_MACROS: use the macros (see below) Note that
407 * the macros evaluate their argument multiple times.
408 * PNG_NO_USE_READ_MACROS: call the relevant library function.
409 *
410 * Use the alternative algorithm for compositing alpha samples that
411 * does not use division?
412 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
413 * algorithm.
414 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
415 *
416 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
417 * false?
418 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
419 * APIs to png_warning.
420 * Otherwise the calls are mapped to png_error.
421 */
422
423/* Section 3: type definitions, including structures and compile time
424 * constants.
425 * See pngconf.h for base types that vary by machine/system
426 */
427
428/* This triggers a compiler error in png.c, if png.c and png.h
429 * do not agree upon the version number.
430 */
431typedef char* png_libpng_version_1_6_37;
432
433/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
434 *
435 * png_struct is the cache of information used while reading or writing a single
436 * PNG file. One of these is always required, although the simplified API
437 * (below) hides the creation and destruction of it.
438 */
439typedef struct png_struct_def png_struct;
440typedef const png_struct * png_const_structp;
441typedef png_struct * png_structp;
442typedef png_struct * * png_structpp;
443
444/* png_info contains information read from or to be written to a PNG file. One
445 * or more of these must exist while reading or creating a PNG file. The
446 * information is not used by libpng during read but is used to control what
447 * gets written when a PNG file is created. "png_get_" function calls read
448 * information during read and "png_set_" functions calls write information
449 * when creating a PNG.
450 * been moved into a separate header file that is not accessible to
451 * applications. Read libpng-manual.txt or libpng.3 for more info.
452 */
453typedef struct png_info_def png_info;
454typedef png_info * png_infop;
455typedef const png_info * png_const_infop;
456typedef png_info * * png_infopp;
457
458/* Types with names ending 'p' are pointer types. The corresponding types with
459 * names ending 'rp' are identical pointer types except that the pointer is
460 * marked 'restrict', which means that it is the only pointer to the object
461 * passed to the function. Applications should not use the 'restrict' types;
462 * it is always valid to pass 'p' to a pointer with a function argument of the
463 * corresponding 'rp' type. Different compilers have different rules with
464 * regard to type matching in the presence of 'restrict'. For backward
465 * compatibility libpng callbacks never have 'restrict' in their parameters and,
466 * consequentially, writing portable application code is extremely difficult if
467 * an attempt is made to use 'restrict'.
468 */
469typedef png_struct * PNG_RESTRICT png_structrp;
470typedef const png_struct * PNG_RESTRICT png_const_structrp;
471typedef png_info * PNG_RESTRICT png_inforp;
472typedef const png_info * PNG_RESTRICT png_const_inforp;
473
474/* Three color definitions. The order of the red, green, and blue, (and the
475 * exact size) is not important, although the size of the fields need to
476 * be png_byte or png_uint_16 (as defined below).
477 */
478typedef struct png_color_struct
479{
480 png_byte red;
481 png_byte green;
482 png_byte blue;
483} png_color;
484typedef png_color * png_colorp;
485typedef const png_color * png_const_colorp;
486typedef png_color * * png_colorpp;
487
488typedef struct png_color_16_struct
489{
490 png_byte index; /* used for palette files */
491 png_uint_16 red; /* for use in red green blue files */
492 png_uint_16 green;
493 png_uint_16 blue;
494 png_uint_16 gray; /* for use in grayscale files */
495} png_color_16;
496typedef png_color_16 * png_color_16p;
497typedef const png_color_16 * png_const_color_16p;
498typedef png_color_16 * * png_color_16pp;
499
500typedef struct png_color_8_struct
501{
502 png_byte red; /* for use in red green blue files */
503 png_byte green;
504 png_byte blue;
505 png_byte gray; /* for use in grayscale files */
506 png_byte alpha; /* for alpha channel files */
507} png_color_8;
508typedef png_color_8 * png_color_8p;
509typedef const png_color_8 * png_const_color_8p;
510typedef png_color_8 * * png_color_8pp;
511
512/*
513 * The following two structures are used for the in-core representation
514 * of sPLT chunks.
515 */
516typedef struct png_sPLT_entry_struct
517{
518 png_uint_16 red;
519 png_uint_16 green;
520 png_uint_16 blue;
521 png_uint_16 alpha;
522 png_uint_16 frequency;
523} png_sPLT_entry;
524typedef png_sPLT_entry * png_sPLT_entryp;
525typedef const png_sPLT_entry * png_const_sPLT_entryp;
526typedef png_sPLT_entry * * png_sPLT_entrypp;
527
528/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
529 * occupy the LSB of their respective members, and the MSB of each member
530 * is zero-filled. The frequency member always occupies the full 16 bits.
531 */
532
533typedef struct png_sPLT_struct
534{
535 png_charp name; /* palette name */
536 png_byte depth; /* depth of palette samples */
537 png_sPLT_entryp entries; /* palette entries */
538 png_int_32 nentries; /* number of palette entries */
539} png_sPLT_t;
540typedef png_sPLT_t * png_sPLT_tp;
541typedef const png_sPLT_t * png_const_sPLT_tp;
542typedef png_sPLT_t * * png_sPLT_tpp;
543
544#ifdef PNG_TEXT_SUPPORTED
545/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
546 * and whether that contents is compressed or not. The "key" field
547 * points to a regular zero-terminated C string. The "text" fields can be a
548 * regular C string, an empty string, or a NULL pointer.
549 * However, the structure returned by png_get_text() will always contain
550 * the "text" field as a regular zero-terminated C string (possibly
551 * empty), never a NULL pointer, so it can be safely used in printf() and
552 * other string-handling functions. Note that the "itxt_length", "lang", and
553 * "lang_key" members of the structure only exist when the library is built
554 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
555 * default without iTXt support. Also note that when iTXt *is* supported,
556 * the "lang" and "lang_key" fields contain NULL pointers when the
557 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
558 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
559 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
560 * which is always 0 or 1, or its "compression method" which is always 0.
561 */
562typedef struct png_text_struct
563{
564 int compression; /* compression value:
565 -1: tEXt, none
566 0: zTXt, deflate
567 1: iTXt, none
568 2: iTXt, deflate */
569 png_charp key; /* keyword, 1-79 character description of "text" */
570 png_charp text; /* comment, may be an empty string (ie "")
571 or a NULL pointer */
572 size_t text_length; /* length of the text string */
573 size_t itxt_length; /* length of the itxt string */
574 png_charp lang; /* language code, 0-79 characters
575 or a NULL pointer */
576 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
577 chars or a NULL pointer */
578} png_text;
579typedef png_text * png_textp;
580typedef const png_text * png_const_textp;
581typedef png_text * * png_textpp;
582#endif
583
584/* Supported compression types for text in PNG files (tEXt, and zTXt).
585 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
586#define PNG_TEXT_COMPRESSION_NONE_WR -3
587#define PNG_TEXT_COMPRESSION_zTXt_WR -2
588#define PNG_TEXT_COMPRESSION_NONE -1
589#define PNG_TEXT_COMPRESSION_zTXt 0
590#define PNG_ITXT_COMPRESSION_NONE 1
591#define PNG_ITXT_COMPRESSION_zTXt 2
592#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
593
594/* png_time is a way to hold the time in an machine independent way.
595 * Two conversions are provided, both from time_t and struct tm. There
596 * is no portable way to convert to either of these structures, as far
597 * as I know. If you know of a portable way, send it to me. As a side
598 * note - PNG has always been Year 2000 compliant!
599 */
600typedef struct png_time_struct
601{
602 png_uint_16 year; /* full year, as in, 1995 */
603 png_byte month; /* month of year, 1 - 12 */
604 png_byte day; /* day of month, 1 - 31 */
605 png_byte hour; /* hour of day, 0 - 23 */
606 png_byte minute; /* minute of hour, 0 - 59 */
607 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
608} png_time;
609typedef png_time * png_timep;
610typedef const png_time * png_const_timep;
611typedef png_time * * png_timepp;
612
613#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
614 defined(PNG_USER_CHUNKS_SUPPORTED)
615/* png_unknown_chunk is a structure to hold queued chunks for which there is
616 * no specific support. The idea is that we can use this to queue
617 * up private chunks for output even though the library doesn't actually
618 * know about their semantics.
619 *
620 * The data in the structure is set by libpng on read and used on write.
621 */
622typedef struct png_unknown_chunk_t
623{
624 png_byte name[5]; /* Textual chunk name with '\0' terminator */
625 png_byte *data; /* Data, should not be modified on read! */
626 size_t size;
627
628 /* On write 'location' must be set using the flag values listed below.
629 * Notice that on read it is set by libpng however the values stored have
630 * more bits set than are listed below. Always treat the value as a
631 * bitmask. On write set only one bit - setting multiple bits may cause the
632 * chunk to be written in multiple places.
633 */
634 png_byte location; /* mode of operation at read time */
635}
636png_unknown_chunk;
637
638typedef png_unknown_chunk * png_unknown_chunkp;
639typedef const png_unknown_chunk * png_const_unknown_chunkp;
640typedef png_unknown_chunk * * png_unknown_chunkpp;
641#endif
642
643/* Flag values for the unknown chunk location byte. */
644#define PNG_HAVE_IHDR 0x01
645#define PNG_HAVE_PLTE 0x02
646#define PNG_AFTER_IDAT 0x08
647
648/* Maximum positive integer used in PNG is (2^31)-1 */
649#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
650#define PNG_UINT_32_MAX ((png_uint_32)(-1))
651#define PNG_SIZE_MAX ((size_t)(-1))
652
653/* These are constants for fixed point values encoded in the
654 * PNG specification manner (x100000)
655 */
656#define PNG_FP_1 100000
657#define PNG_FP_HALF 50000
658#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
659#define PNG_FP_MIN (-PNG_FP_MAX)
660
661/* These describe the color_type field in png_info. */
662/* color type masks */
663#define PNG_COLOR_MASK_PALETTE 1
664#define PNG_COLOR_MASK_COLOR 2
665#define PNG_COLOR_MASK_ALPHA 4
666
667/* color types. Note that not all combinations are legal */
668#define PNG_COLOR_TYPE_GRAY 0
669#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
670#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
671#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
672#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
673/* aliases */
674#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
675#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
676
677/* This is for compression type. PNG 1.0-1.2 only define the single type. */
678#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
679#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
680
681/* This is for filter type. PNG 1.0-1.2 only define the single type. */
682#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
683#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
684#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
685
686/* These are for the interlacing type. These values should NOT be changed. */
687#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
688#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
689#define PNG_INTERLACE_LAST 2 /* Not a valid value */
690
691/* These are for the oFFs chunk. These values should NOT be changed. */
692#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
693#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
694#define PNG_OFFSET_LAST 2 /* Not a valid value */
695
696/* These are for the pCAL chunk. These values should NOT be changed. */
697#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
698#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
699#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
700#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
701#define PNG_EQUATION_LAST 4 /* Not a valid value */
702
703/* These are for the sCAL chunk. These values should NOT be changed. */
704#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
705#define PNG_SCALE_METER 1 /* meters per pixel */
706#define PNG_SCALE_RADIAN 2 /* radians per pixel */
707#define PNG_SCALE_LAST 3 /* Not a valid value */
708
709/* These are for the pHYs chunk. These values should NOT be changed. */
710#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
711#define PNG_RESOLUTION_METER 1 /* pixels/meter */
712#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
713
714/* These are for the sRGB chunk. These values should NOT be changed. */
715#define PNG_sRGB_INTENT_PERCEPTUAL 0
716#define PNG_sRGB_INTENT_RELATIVE 1
717#define PNG_sRGB_INTENT_SATURATION 2
718#define PNG_sRGB_INTENT_ABSOLUTE 3
719#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
720
721/* This is for text chunks */
722#define PNG_KEYWORD_MAX_LENGTH 79
723
724/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
725#define PNG_MAX_PALETTE_LENGTH 256
726
727/* These determine if an ancillary chunk's data has been successfully read
728 * from the PNG header, or if the application has filled in the corresponding
729 * data in the info_struct to be written into the output file. The values
730 * of the PNG_INFO_<chunk> defines should NOT be changed.
731 */
732#define PNG_INFO_gAMA 0x0001U
733#define PNG_INFO_sBIT 0x0002U
734#define PNG_INFO_cHRM 0x0004U
735#define PNG_INFO_PLTE 0x0008U
736#define PNG_INFO_tRNS 0x0010U
737#define PNG_INFO_bKGD 0x0020U
738#define PNG_INFO_hIST 0x0040U
739#define PNG_INFO_pHYs 0x0080U
740#define PNG_INFO_oFFs 0x0100U
741#define PNG_INFO_tIME 0x0200U
742#define PNG_INFO_pCAL 0x0400U
743#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
744#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
745#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
746#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
747#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
748#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
749
750/* This is used for the transformation routines, as some of them
751 * change these values for the row. It also should enable using
752 * the routines for other purposes.
753 */
754typedef struct png_row_info_struct
755{
756 png_uint_32 width; /* width of row */
757 size_t rowbytes; /* number of bytes in row */
758 png_byte color_type; /* color type of row */
759 png_byte bit_depth; /* bit depth of row */
760 png_byte channels; /* number of channels (1, 2, 3, or 4) */
761 png_byte pixel_depth; /* bits per pixel (depth * channels) */
762} png_row_info;
763
764typedef png_row_info * png_row_infop;
765typedef png_row_info * * png_row_infopp;
766
767/* These are the function types for the I/O functions and for the functions
768 * that allow the user to override the default I/O functions with his or her
769 * own. The png_error_ptr type should match that of user-supplied warning
770 * and error functions, while the png_rw_ptr type should match that of the
771 * user read/write data functions. Note that the 'write' function must not
772 * modify the buffer it is passed. The 'read' function, on the other hand, is
773 * expected to return the read data in the buffer.
774 */
775typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
776typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
777typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
778typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
779 int));
780typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
781 int));
782
783#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
784typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
785typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
786
787/* The following callback receives png_uint_32 row_number, int pass for the
788 * png_bytep data of the row. When transforming an interlaced image the
789 * row number is the row number within the sub-image of the interlace pass, so
790 * the value will increase to the height of the sub-image (not the full image)
791 * then reset to 0 for the next pass.
792 *
793 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
794 * find the output pixel (x,y) given an interlaced sub-image pixel
795 * (row,col,pass). (See below for these macros.)
796 */
797typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
798 png_uint_32, int));
799#endif
800
801#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
802 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
803typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
804 png_bytep));
805#endif
806
807#ifdef PNG_USER_CHUNKS_SUPPORTED
808typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
809 png_unknown_chunkp));
810#endif
811#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
812/* not used anywhere */
813/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
814#endif
815
816#ifdef PNG_SETJMP_SUPPORTED
817/* This must match the function definition in <setjmp.h>, and the application
818 * must include this before png.h to obtain the definition of jmp_buf. The
819 * function is required to be PNG_NORETURN, but this is not checked. If the
820 * function does return the application will crash via an abort() or similar
821 * system level call.
822 *
823 * If you get a warning here while building the library you may need to make
824 * changes to ensure that pnglibconf.h records the calling convention used by
825 * your compiler. This may be very difficult - try using a different compiler
826 * to build the library!
827 */
828PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
829#endif
830
831/* Transform masks for the high-level interface */
832#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
833#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
834#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
835#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
836#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
837#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
838#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
839#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
840#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
841#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
842#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
843#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
844#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
845/* Added to libpng-1.2.34 */
846#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
847#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
848/* Added to libpng-1.4.0 */
849#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
850/* Added to libpng-1.5.4 */
851#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
852#if INT_MAX >= 0x8000 /* else this might break */
853#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
854#endif
855
856/* Flags for MNG supported features */
857#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
858#define PNG_FLAG_MNG_FILTER_64 0x04
859#define PNG_ALL_MNG_FEATURES 0x05
860
861/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
862 * this allowed the zlib default functions to be used on Windows
863 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
864 * ignores the first argument) should be completely compatible with the
865 * following.
866 */
867typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
868 png_alloc_size_t));
869typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
870
871/* Section 4: exported functions
872 * Here are the function definitions most commonly used. This is not
873 * the place to find out how to use libpng. See libpng-manual.txt for the
874 * full explanation, see example.c for the summary. This just provides
875 * a simple one line description of the use of each function.
876 *
877 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
878 * pngconf.h and in the *.dfn files in the scripts directory.
879 *
880 * PNG_EXPORT(ordinal, type, name, (args));
881 *
882 * ordinal: ordinal that is used while building
883 * *.def files. The ordinal value is only
884 * relevant when preprocessing png.h with
885 * the *.dfn files for building symbol table
886 * entries, and are removed by pngconf.h.
887 * type: return type of the function
888 * name: function name
889 * args: function arguments, with types
890 *
891 * When we wish to append attributes to a function prototype we use
892 * the PNG_EXPORTA() macro instead.
893 *
894 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
895 *
896 * ordinal, type, name, and args: same as in PNG_EXPORT().
897 * attributes: function attributes
898 */
899
900/* Returns the version number of the library */
901PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
902
903/* Tell lib we have already handled the first <num_bytes> magic bytes.
904 * Handling more than 8 bytes from the beginning of the file is an error.
905 */
906PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
907
908/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
909 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
910 * signature, and non-zero otherwise. Having num_to_check == 0 or
911 * start > 7 will always fail (ie return non-zero).
912 */
913PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
914 size_t num_to_check));
915
916/* Simple signature checking function. This is the same as calling
917 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
918 */
919#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
920
921/* Allocate and initialize png_ptr struct for reading, and any other memory. */
922PNG_EXPORTA(4, png_structp, png_create_read_struct,
923 (png_const_charp user_png_ver, png_voidp error_ptr,
924 png_error_ptr error_fn, png_error_ptr warn_fn),
925 PNG_ALLOCATED);
926
927/* Allocate and initialize png_ptr struct for writing, and any other memory */
928PNG_EXPORTA(5, png_structp, png_create_write_struct,
929 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
930 png_error_ptr warn_fn),
931 PNG_ALLOCATED);
932
933PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
934 (png_const_structrp png_ptr));
935
936PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
937 size_t size));
938
939/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
940 * match up.
941 */
942#ifdef PNG_SETJMP_SUPPORTED
943/* This function returns the jmp_buf built in to *png_ptr. It must be
944 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
945 * unless the default error function is overridden in which case NULL is
946 * acceptable. The size of the jmp_buf is checked against the actual size
947 * allocated by the library - the call will return NULL on a mismatch
948 * indicating an ABI mismatch.
949 */
950PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
951 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
952# define png_jmpbuf(png_ptr) \
953 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
954#else
955# define png_jmpbuf(png_ptr) \
956 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
957#endif
958/* This function should be used by libpng applications in place of
959 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
960 * will use it; otherwise it will call PNG_ABORT(). This function was
961 * added in libpng-1.5.0.
962 */
963PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
964 PNG_NORETURN);
965
966#ifdef PNG_READ_SUPPORTED
967/* Reset the compression stream */
968PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
969#endif
970
971/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
972#ifdef PNG_USER_MEM_SUPPORTED
973PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
974 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
975 png_error_ptr warn_fn,
976 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
977 PNG_ALLOCATED);
978PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
979 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
980 png_error_ptr warn_fn,
981 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
982 PNG_ALLOCATED);
983#endif
984
985/* Write the PNG file signature. */
986PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
987
988/* Write a PNG chunk - size, type, (optional) data, CRC. */
989PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
990 chunk_name, png_const_bytep data, size_t length));
991
992/* Write the start of a PNG chunk - length and chunk name. */
993PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
994 png_const_bytep chunk_name, png_uint_32 length));
995
996/* Write the data of a PNG chunk started with png_write_chunk_start(). */
997PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
998 png_const_bytep data, size_t length));
999
1000/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1001PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1002
1003/* Allocate and initialize the info structure */
1004PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1005 PNG_ALLOCATED);
1006
1007/* DEPRECATED: this function allowed init structures to be created using the
1008 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1009 * the API will be removed in the future.
1010 */
1011PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1012 size_t png_info_struct_size), PNG_DEPRECATED);
1013
1014/* Writes all the PNG information before the image. */
1015PNG_EXPORT(20, void, png_write_info_before_PLTE,
1016 (png_structrp png_ptr, png_const_inforp info_ptr));
1017PNG_EXPORT(21, void, png_write_info,
1018 (png_structrp png_ptr, png_const_inforp info_ptr));
1019
1020#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1021/* Read the information before the actual image data. */
1022PNG_EXPORT(22, void, png_read_info,
1023 (png_structrp png_ptr, png_inforp info_ptr));
1024#endif
1025
1026#ifdef PNG_TIME_RFC1123_SUPPORTED
1027 /* Convert to a US string format: there is no localization support in this
1028 * routine. The original implementation used a 29 character buffer in
1029 * png_struct, this will be removed in future versions.
1030 */
1031#if PNG_LIBPNG_VER < 10700
1032/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1033PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1034 png_const_timep ptime),PNG_DEPRECATED);
1035#endif
1036PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1037 png_const_timep ptime));
1038#endif
1039
1040#ifdef PNG_CONVERT_tIME_SUPPORTED
1041/* Convert from a struct tm to png_time */
1042PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1043 const struct tm * ttime));
1044
1045/* Convert from time_t to png_time. Uses gmtime() */
1046PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1047#endif /* CONVERT_tIME */
1048
1049#ifdef PNG_READ_EXPAND_SUPPORTED
1050/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1051PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1052PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1053PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1054PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1055#endif
1056
1057#ifdef PNG_READ_EXPAND_16_SUPPORTED
1058/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1059 * of a tRNS chunk if present.
1060 */
1061PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1062#endif
1063
1064#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1065/* Use blue, green, red order for pixels. */
1066PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1067#endif
1068
1069#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1070/* Expand the grayscale to 24-bit RGB if necessary. */
1071PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1072#endif
1073
1074#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1075/* Reduce RGB to grayscale. */
1076#define PNG_ERROR_ACTION_NONE 1
1077#define PNG_ERROR_ACTION_WARN 2
1078#define PNG_ERROR_ACTION_ERROR 3
1079#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1080
1081PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1082 int error_action, double red, double green))
1083PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1084 int error_action, png_fixed_point red, png_fixed_point green))
1085
1086PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1087 png_ptr));
1088#endif
1089
1090#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1091PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1092 png_colorp palette));
1093#endif
1094
1095#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1096/* How the alpha channel is interpreted - this affects how the color channels
1097 * of a PNG file are returned to the calling application when an alpha channel,
1098 * or a tRNS chunk in a palette file, is present.
1099 *
1100 * This has no effect on the way pixels are written into a PNG output
1101 * datastream. The color samples in a PNG datastream are never premultiplied
1102 * with the alpha samples.
1103 *
1104 * The default is to return data according to the PNG specification: the alpha
1105 * channel is a linear measure of the contribution of the pixel to the
1106 * corresponding composited pixel, and the color channels are unassociated
1107 * (not premultiplied). The gamma encoded color channels must be scaled
1108 * according to the contribution and to do this it is necessary to undo
1109 * the encoding, scale the color values, perform the composition and re-encode
1110 * the values. This is the 'PNG' mode.
1111 *
1112 * The alternative is to 'associate' the alpha with the color information by
1113 * storing color channel values that have been scaled by the alpha.
1114 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1115 * (the latter being the two common names for associated alpha color channels).
1116 *
1117 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1118 * value is equal to the maximum value.
1119 *
1120 * The final choice is to gamma encode the alpha channel as well. This is
1121 * broken because, in practice, no implementation that uses this choice
1122 * correctly undoes the encoding before handling alpha composition. Use this
1123 * choice only if other serious errors in the software or hardware you use
1124 * mandate it; the typical serious error is for dark halos to appear around
1125 * opaque areas of the composited PNG image because of arithmetic overflow.
1126 *
1127 * The API function png_set_alpha_mode specifies which of these choices to use
1128 * with an enumerated 'mode' value and the gamma of the required output:
1129 */
1130#define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1131#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1132#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1133#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1134#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1135#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1136
1137PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1138 double output_gamma))
1139PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1140 int mode, png_fixed_point output_gamma))
1141#endif
1142
1143#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1144/* The output_gamma value is a screen gamma in libpng terminology: it expresses
1145 * how to decode the output values, not how they are encoded.
1146 */
1147#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1148#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1149#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1150#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1151#endif
1152
1153/* The following are examples of calls to png_set_alpha_mode to achieve the
1154 * required overall gamma correction and, where necessary, alpha
1155 * premultiplication.
1156 *
1157 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1158 * This is the default libpng handling of the alpha channel - it is not
1159 * pre-multiplied into the color components. In addition the call states
1160 * that the output is for a sRGB system and causes all PNG files without gAMA
1161 * chunks to be assumed to be encoded using sRGB.
1162 *
1163 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1164 * In this case the output is assumed to be something like an sRGB conformant
1165 * display preceded by a power-law lookup table of power 1.45. This is how
1166 * early Mac systems behaved.
1167 *
1168 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1169 * This is the classic Jim Blinn approach and will work in academic
1170 * environments where everything is done by the book. It has the shortcoming
1171 * of assuming that input PNG data with no gamma information is linear - this
1172 * is unlikely to be correct unless the PNG files where generated locally.
1173 * Most of the time the output precision will be so low as to show
1174 * significant banding in dark areas of the image.
1175 *
1176 * png_set_expand_16(pp);
1177 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1178 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1179 * are assumed to have the sRGB encoding if not marked with a gamma value and
1180 * the output is always 16 bits per component. This permits accurate scaling
1181 * and processing of the data. If you know that your input PNG files were
1182 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1183 * correct value for your system.
1184 *
1185 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1186 * If you just need to composite the PNG image onto an existing background
1187 * and if you control the code that does this you can use the optimization
1188 * setting. In this case you just copy completely opaque pixels to the
1189 * output. For pixels that are not completely transparent (you just skip
1190 * those) you do the composition math using png_composite or png_composite_16
1191 * below then encode the resultant 8-bit or 16-bit values to match the output
1192 * encoding.
1193 *
1194 * Other cases
1195 * If neither the PNG nor the standard linear encoding work for you because
1196 * of the software or hardware you use then you have a big problem. The PNG
1197 * case will probably result in halos around the image. The linear encoding
1198 * will probably result in a washed out, too bright, image (it's actually too
1199 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1200 * substantially reduce the halos. Alternatively try:
1201 *
1202 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1203 * This option will also reduce the halos, but there will be slight dark
1204 * halos round the opaque parts of the image where the background is light.
1205 * In the OPTIMIZED mode the halos will be light halos where the background
1206 * is dark. Take your pick - the halos are unavoidable unless you can get
1207 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1208 * faster.)
1209 *
1210 * When the default gamma of PNG files doesn't match the output gamma.
1211 * If you have PNG files with no gamma information png_set_alpha_mode allows
1212 * you to provide a default gamma, but it also sets the output gamma to the
1213 * matching value. If you know your PNG files have a gamma that doesn't
1214 * match the output you can take advantage of the fact that
1215 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1216 * default if it is not already set:
1217 *
1218 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1219 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1220 * The first call sets both the default and the output gamma values, the
1221 * second call overrides the output gamma without changing the default. This
1222 * is easier than achieving the same effect with png_set_gamma. You must use
1223 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1224 * fire if more than one call to png_set_alpha_mode and png_set_background is
1225 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1226 * are ignored.
1227 */
1228
1229#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1230PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1231#endif
1232
1233#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1234 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1235PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1236#endif
1237
1238#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1239 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1240PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1241#endif
1242
1243#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1244/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1245PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1246 int flags));
1247/* The values of the PNG_FILLER_ defines should NOT be changed */
1248# define PNG_FILLER_BEFORE 0
1249# define PNG_FILLER_AFTER 1
1250/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1251PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1252 png_uint_32 filler, int flags));
1253#endif /* READ_FILLER || WRITE_FILLER */
1254
1255#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1256/* Swap bytes in 16-bit depth files. */
1257PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1258#endif
1259
1260#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1261/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1262PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1263#endif
1264
1265#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1266 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1267/* Swap packing order of pixels in bytes. */
1268PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1269#endif
1270
1271#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1272/* Converts files to legal bit depths. */
1273PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1274 true_bits));
1275#endif
1276
1277#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1278 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1279/* Have the code handle the interlacing. Returns the number of passes.
1280 * MUST be called before png_read_update_info or png_start_read_image,
1281 * otherwise it will not have the desired effect. Note that it is still
1282 * necessary to call png_read_row or png_read_rows png_get_image_height
1283 * times for each pass.
1284*/
1285PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1286#endif
1287
1288#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1289/* Invert monochrome files */
1290PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1291#endif
1292
1293#ifdef PNG_READ_BACKGROUND_SUPPORTED
1294/* Handle alpha and tRNS by replacing with a background color. Prior to
1295 * libpng-1.5.4 this API must not be called before the PNG file header has been
1296 * read. Doing so will result in unexpected behavior and possible warnings or
1297 * errors if the PNG file contains a bKGD chunk.
1298 */
1299PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1300 png_const_color_16p background_color, int background_gamma_code,
1301 int need_expand, double background_gamma))
1302PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1303 png_const_color_16p background_color, int background_gamma_code,
1304 int need_expand, png_fixed_point background_gamma))
1305#endif
1306#ifdef PNG_READ_BACKGROUND_SUPPORTED
1307# define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1308# define PNG_BACKGROUND_GAMMA_SCREEN 1
1309# define PNG_BACKGROUND_GAMMA_FILE 2
1310# define PNG_BACKGROUND_GAMMA_UNIQUE 3
1311#endif
1312
1313#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1314/* Scale a 16-bit depth file down to 8-bit, accurately. */
1315PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1316#endif
1317
1318#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1319#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
1320/* Strip the second byte of information from a 16-bit depth file. */
1321PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1322#endif
1323
1324#ifdef PNG_READ_QUANTIZE_SUPPORTED
1325/* Turn on quantizing, and reduce the palette to the number of colors
1326 * available.
1327 */
1328PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1329 png_colorp palette, int num_palette, int maximum_colors,
1330 png_const_uint_16p histogram, int full_quantize));
1331#endif
1332
1333#ifdef PNG_READ_GAMMA_SUPPORTED
1334/* The threshold on gamma processing is configurable but hard-wired into the
1335 * library. The following is the floating point variant.
1336 */
1337#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1338
1339/* Handle gamma correction. Screen_gamma=(display_exponent).
1340 * NOTE: this API simply sets the screen and file gamma values. It will
1341 * therefore override the value for gamma in a PNG file if it is called after
1342 * the file header has been read - use with care - call before reading the PNG
1343 * file for best results!
1344 *
1345 * These routines accept the same gamma values as png_set_alpha_mode (described
1346 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1347 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1348 * is the inverse of a 'screen gamma' value.
1349 */
1350PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1351 double screen_gamma, double override_file_gamma))
1352PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1353 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1354#endif
1355
1356#ifdef PNG_WRITE_FLUSH_SUPPORTED
1357/* Set how many lines between output flushes - 0 for no flushing */
1358PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1359/* Flush the current PNG output buffer */
1360PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1361#endif
1362
1363/* Optional update palette with requested transformations */
1364PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1365
1366/* Optional call to update the users info structure */
1367PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1368 png_inforp info_ptr));
1369
1370#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1371/* Read one or more rows of image data. */
1372PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1373 png_bytepp display_row, png_uint_32 num_rows));
1374#endif
1375
1376#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1377/* Read a row of data. */
1378PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1379 png_bytep display_row));
1380#endif
1381
1382#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1383/* Read the whole image into memory at once. */
1384PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1385#endif
1386
1387/* Write a row of image data */
1388PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1389 png_const_bytep row));
1390
1391/* Write a few rows of image data: (*row) is not written; however, the type
1392 * is declared as writeable to maintain compatibility with previous versions
1393 * of libpng and to allow the 'display_row' array from read_rows to be passed
1394 * unchanged to write_rows.
1395 */
1396PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1397 png_uint_32 num_rows));
1398
1399/* Write the image data */
1400PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1401
1402/* Write the end of the PNG file. */
1403PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1404 png_inforp info_ptr));
1405
1406#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1407/* Read the end of the PNG file. */
1408PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1409#endif
1410
1411/* Free any memory associated with the png_info_struct */
1412PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1413 png_infopp info_ptr_ptr));
1414
1415/* Free any memory associated with the png_struct and the png_info_structs */
1416PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1417 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1418
1419/* Free any memory associated with the png_struct and the png_info_structs */
1420PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1421 png_infopp info_ptr_ptr));
1422
1423/* Set the libpng method of handling chunk CRC errors */
1424PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1425 int ancil_action));
1426
1427/* Values for png_set_crc_action() say how to handle CRC errors in
1428 * ancillary and critical chunks, and whether to use the data contained
1429 * therein. Note that it is impossible to "discard" data in a critical
1430 * chunk. For versions prior to 0.90, the action was always error/quit,
1431 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1432 * chunks is warn/discard. These values should NOT be changed.
1433 *
1434 * value action:critical action:ancillary
1435 */
1436#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1437#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1438#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1439#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1440#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1441#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1442
1443#ifdef PNG_WRITE_SUPPORTED
1444/* These functions give the user control over the scan-line filtering in
1445 * libpng and the compression methods used by zlib. These functions are
1446 * mainly useful for testing, as the defaults should work with most users.
1447 * Those users who are tight on memory or want faster performance at the
1448 * expense of compression can modify them. See the compression library
1449 * header file (zlib.h) for an explination of the compression functions.
1450 */
1451
1452/* Set the filtering method(s) used by libpng. Currently, the only valid
1453 * value for "method" is 0.
1454 */
1455PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1456 int filters));
1457#endif /* WRITE */
1458
1459/* Flags for png_set_filter() to say which filters to use. The flags
1460 * are chosen so that they don't conflict with real filter types
1461 * below, in case they are supplied instead of the #defined constants.
1462 * These values should NOT be changed.
1463 */
1464#define PNG_NO_FILTERS 0x00
1465#define PNG_FILTER_NONE 0x08
1466#define PNG_FILTER_SUB 0x10
1467#define PNG_FILTER_UP 0x20
1468#define PNG_FILTER_AVG 0x40
1469#define PNG_FILTER_PAETH 0x80
1470#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
1471#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
1472
1473/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1474 * These defines should NOT be changed.
1475 */
1476#define PNG_FILTER_VALUE_NONE 0
1477#define PNG_FILTER_VALUE_SUB 1
1478#define PNG_FILTER_VALUE_UP 2
1479#define PNG_FILTER_VALUE_AVG 3
1480#define PNG_FILTER_VALUE_PAETH 4
1481#define PNG_FILTER_VALUE_LAST 5
1482
1483#ifdef PNG_WRITE_SUPPORTED
1484#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1485PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1486 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1487 png_const_doublep filter_costs))
1488PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1489 (png_structrp png_ptr, int heuristic_method, int num_weights,
1490 png_const_fixed_point_p filter_weights,
1491 png_const_fixed_point_p filter_costs))
1492#endif /* WRITE_WEIGHTED_FILTER */
1493
1494/* The following are no longer used and will be removed from libpng-1.7: */
1495#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1496#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1497#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1498#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1499
1500/* Set the library compression level. Currently, valid values range from
1501 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1502 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1503 * shown that zlib compression levels 3-6 usually perform as well as level 9
1504 * for PNG images, and do considerably fewer caclulations. In the future,
1505 * these values may not correspond directly to the zlib compression levels.
1506 */
1507#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1508PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1509 int level));
1510
1511PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1512 int mem_level));
1513
1514PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1515 int strategy));
1516
1517/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1518 * smaller value of window_bits if it can do so safely.
1519 */
1520PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1521 int window_bits));
1522
1523PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1524 int method));
1525#endif /* WRITE_CUSTOMIZE_COMPRESSION */
1526
1527#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1528/* Also set zlib parameters for compressing non-IDAT chunks */
1529PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1530 int level));
1531
1532PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1533 int mem_level));
1534
1535PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1536 int strategy));
1537
1538/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1539 * smaller value of window_bits if it can do so safely.
1540 */
1541PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1542 (png_structrp png_ptr, int window_bits));
1543
1544PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1545 int method));
1546#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1547#endif /* WRITE */
1548
1549/* These next functions are called for input/output, memory, and error
1550 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1551 * and call standard C I/O routines such as fread(), fwrite(), and
1552 * fprintf(). These functions can be made to use other I/O routines
1553 * at run time for those applications that need to handle I/O in a
1554 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1555 * more information.
1556 */
1557
1558#ifdef PNG_STDIO_SUPPORTED
1559/* Initialize the input/output for the PNG file to the default functions. */
1560PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1561#endif
1562
1563/* Replace the (error and abort), and warning functions with user
1564 * supplied functions. If no messages are to be printed you must still
1565 * write and use replacement functions. The replacement error_fn should
1566 * still do a longjmp to the last setjmp location if you are using this
1567 * method of error handling. If error_fn or warning_fn is NULL, the
1568 * default function will be used.
1569 */
1570
1571PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1572 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1573
1574/* Return the user pointer associated with the error functions */
1575PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1576
1577/* Replace the default data output functions with a user supplied one(s).
1578 * If buffered output is not used, then output_flush_fn can be set to NULL.
1579 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1580 * output_flush_fn will be ignored (and thus can be NULL).
1581 * It is probably a mistake to use NULL for output_flush_fn if
1582 * write_data_fn is not also NULL unless you have built libpng with
1583 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1584 * default flush function, which uses the standard *FILE structure, will
1585 * be used.
1586 */
1587PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1588 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1589
1590/* Replace the default data input function with a user supplied one. */
1591PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1592 png_rw_ptr read_data_fn));
1593
1594/* Return the user pointer associated with the I/O functions */
1595PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1596
1597PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1598 png_read_status_ptr read_row_fn));
1599
1600PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1601 png_write_status_ptr write_row_fn));
1602
1603#ifdef PNG_USER_MEM_SUPPORTED
1604/* Replace the default memory allocation functions with user supplied one(s). */
1605PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1606 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1607/* Return the user pointer associated with the memory functions */
1608PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1609#endif
1610
1611#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1612PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1613 png_user_transform_ptr read_user_transform_fn));
1614#endif
1615
1616#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1617PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1618 png_user_transform_ptr write_user_transform_fn));
1619#endif
1620
1621#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1622PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1623 png_voidp user_transform_ptr, int user_transform_depth,
1624 int user_transform_channels));
1625/* Return the user pointer associated with the user transform functions */
1626PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1627 (png_const_structrp png_ptr));
1628#endif
1629
1630#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1631/* Return information about the row currently being processed. Note that these
1632 * APIs do not fail but will return unexpected results if called outside a user
1633 * transform callback. Also note that when transforming an interlaced image the
1634 * row number is the row number within the sub-image of the interlace pass, so
1635 * the value will increase to the height of the sub-image (not the full image)
1636 * then reset to 0 for the next pass.
1637 *
1638 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1639 * find the output pixel (x,y) given an interlaced sub-image pixel
1640 * (row,col,pass). (See below for these macros.)
1641 */
1642PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1643PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1644#endif
1645
1646#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1647/* This callback is called only for *unknown* chunks. If
1648 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1649 * chunks to be treated as unknown, however in this case the callback must do
1650 * any processing required by the chunk (e.g. by calling the appropriate
1651 * png_set_ APIs.)
1652 *
1653 * There is no write support - on write, by default, all the chunks in the
1654 * 'unknown' list are written in the specified position.
1655 *
1656 * The integer return from the callback function is interpreted thus:
1657 *
1658 * negative: An error occurred; png_chunk_error will be called.
1659 * zero: The chunk was not handled, the chunk will be saved. A critical
1660 * chunk will cause an error at this point unless it is to be saved.
1661 * positive: The chunk was handled, libpng will ignore/discard it.
1662 *
1663 * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about
1664 * how this behavior will change in libpng 1.7
1665 */
1666PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1667 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1668#endif
1669
1670#ifdef PNG_USER_CHUNKS_SUPPORTED
1671PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1672#endif
1673
1674#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1675/* Sets the function callbacks for the push reader, and a pointer to a
1676 * user-defined structure available to the callback functions.
1677 */
1678PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1679 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1680 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1681
1682/* Returns the user pointer associated with the push read functions */
1683PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1684 (png_const_structrp png_ptr));
1685
1686/* Function to be called when data becomes available */
1687PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1688 png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
1689
1690/* A function which may be called *only* within png_process_data to stop the
1691 * processing of any more data. The function returns the number of bytes
1692 * remaining, excluding any that libpng has cached internally. A subsequent
1693 * call to png_process_data must supply these bytes again. If the argument
1694 * 'save' is set to true the routine will first save all the pending data and
1695 * will always return 0.
1696 */
1697PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
1698
1699/* A function which may be called *only* outside (after) a call to
1700 * png_process_data. It returns the number of bytes of data to skip in the
1701 * input. Normally it will return 0, but if it returns a non-zero value the
1702 * application must skip than number of bytes of input data and pass the
1703 * following data to the next call to png_process_data.
1704 */
1705PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1706
1707/* Function that combines rows. 'new_row' is a flag that should come from
1708 * the callback and be non-NULL if anything needs to be done; the library
1709 * stores its own version of the new data internally and ignores the passed
1710 * in value.
1711 */
1712PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1713 png_bytep old_row, png_const_bytep new_row));
1714#endif /* PROGRESSIVE_READ */
1715
1716PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1717 png_alloc_size_t size), PNG_ALLOCATED);
1718/* Added at libpng version 1.4.0 */
1719PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1720 png_alloc_size_t size), PNG_ALLOCATED);
1721
1722/* Added at libpng version 1.2.4 */
1723PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1724 png_alloc_size_t size), PNG_ALLOCATED);
1725
1726/* Frees a pointer allocated by png_malloc() */
1727PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1728
1729/* Free data that was allocated internally */
1730PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1731 png_inforp info_ptr, png_uint_32 free_me, int num));
1732
1733/* Reassign responsibility for freeing existing data, whether allocated
1734 * by libpng or by the application; this works on the png_info structure passed
1735 * in, it does not change the state for other png_info structures.
1736 *
1737 * It is unlikely that this function works correctly as of 1.6.0 and using it
1738 * may result either in memory leaks or double free of allocated data.
1739 */
1740PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1741 png_inforp info_ptr, int freer, png_uint_32 mask));
1742
1743/* Assignments for png_data_freer */
1744#define PNG_DESTROY_WILL_FREE_DATA 1
1745#define PNG_SET_WILL_FREE_DATA 1
1746#define PNG_USER_WILL_FREE_DATA 2
1747/* Flags for png_ptr->free_me and info_ptr->free_me */
1748#define PNG_FREE_HIST 0x0008U
1749#define PNG_FREE_ICCP 0x0010U
1750#define PNG_FREE_SPLT 0x0020U
1751#define PNG_FREE_ROWS 0x0040U
1752#define PNG_FREE_PCAL 0x0080U
1753#define PNG_FREE_SCAL 0x0100U
1754#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1755# define PNG_FREE_UNKN 0x0200U
1756#endif
1757/* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */
1758#define PNG_FREE_PLTE 0x1000U
1759#define PNG_FREE_TRNS 0x2000U
1760#define PNG_FREE_TEXT 0x4000U
1761#define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
1762#define PNG_FREE_ALL 0xffffU
1763#define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1764
1765#ifdef PNG_USER_MEM_SUPPORTED
1766PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1767 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1768PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1769 png_voidp ptr), PNG_DEPRECATED);
1770#endif
1771
1772#ifdef PNG_ERROR_TEXT_SUPPORTED
1773/* Fatal error in PNG image of libpng - can't continue */
1774PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1775 png_const_charp error_message), PNG_NORETURN);
1776
1777/* The same, but the chunk name is prepended to the error string. */
1778PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1779 png_const_charp error_message), PNG_NORETURN);
1780
1781#else
1782/* Fatal error in PNG image of libpng - can't continue */
1783PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1784# define png_error(s1,s2) png_err(s1)
1785# define png_chunk_error(s1,s2) png_err(s1)
1786#endif
1787
1788#ifdef PNG_WARNINGS_SUPPORTED
1789/* Non-fatal error in libpng. Can continue, but may have a problem. */
1790PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1791 png_const_charp warning_message));
1792
1793/* Non-fatal error in libpng, chunk name is prepended to message. */
1794PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1795 png_const_charp warning_message));
1796#else
1797# define png_warning(s1,s2) ((void)(s1))
1798# define png_chunk_warning(s1,s2) ((void)(s1))
1799#endif
1800
1801#ifdef PNG_BENIGN_ERRORS_SUPPORTED
1802/* Benign error in libpng. Can continue, but may have a problem.
1803 * User can choose whether to handle as a fatal error or as a warning. */
1804PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1805 png_const_charp warning_message));
1806
1807#ifdef PNG_READ_SUPPORTED
1808/* Same, chunk name is prepended to message (only during read) */
1809PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1810 png_const_charp warning_message));
1811#endif
1812
1813PNG_EXPORT(109, void, png_set_benign_errors,
1814 (png_structrp png_ptr, int allowed));
1815#else
1816# ifdef PNG_ALLOW_BENIGN_ERRORS
1817# define png_benign_error png_warning
1818# define png_chunk_benign_error png_chunk_warning
1819# else
1820# define png_benign_error png_error
1821# define png_chunk_benign_error png_chunk_error
1822# endif
1823#endif
1824
1825/* The png_set_<chunk> functions are for storing values in the png_info_struct.
1826 * Similarly, the png_get_<chunk> calls are used to read values from the
1827 * png_info_struct, either storing the parameters in the passed variables, or
1828 * setting pointers into the png_info_struct where the data is stored. The
1829 * png_get_<chunk> functions return a non-zero value if the data was available
1830 * in info_ptr, or return zero and do not change any of the parameters if the
1831 * data was not available.
1832 *
1833 * These functions should be used instead of directly accessing png_info
1834 * to avoid problems with future changes in the size and internal layout of
1835 * png_info_struct.
1836 */
1837/* Returns "flag" if chunk data is valid in info_ptr. */
1838PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1839 png_const_inforp info_ptr, png_uint_32 flag));
1840
1841/* Returns number of bytes needed to hold a transformed row. */
1842PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1843 png_const_inforp info_ptr));
1844
1845#ifdef PNG_INFO_IMAGE_SUPPORTED
1846/* Returns row_pointers, which is an array of pointers to scanlines that was
1847 * returned from png_read_png().
1848 */
1849PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
1850 png_const_inforp info_ptr));
1851
1852/* Set row_pointers, which is an array of pointers to scanlines for use
1853 * by png_write_png().
1854 */
1855PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
1856 png_inforp info_ptr, png_bytepp row_pointers));
1857#endif
1858
1859/* Returns number of color channels in image. */
1860PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
1861 png_const_inforp info_ptr));
1862
1863#ifdef PNG_EASY_ACCESS_SUPPORTED
1864/* Returns image width in pixels. */
1865PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
1866 png_const_inforp info_ptr));
1867
1868/* Returns image height in pixels. */
1869PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
1870 png_const_inforp info_ptr));
1871
1872/* Returns image bit_depth. */
1873PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
1874 png_const_inforp info_ptr));
1875
1876/* Returns image color_type. */
1877PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
1878 png_const_inforp info_ptr));
1879
1880/* Returns image filter_type. */
1881PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
1882 png_const_inforp info_ptr));
1883
1884/* Returns image interlace_type. */
1885PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
1886 png_const_inforp info_ptr));
1887
1888/* Returns image compression_type. */
1889PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
1890 png_const_inforp info_ptr));
1891
1892/* Returns image resolution in pixels per meter, from pHYs chunk data. */
1893PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
1894 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1895PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
1896 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1897PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
1898 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1899
1900/* Returns pixel aspect ratio, computed from pHYs chunk data. */
1901PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
1902 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1903PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
1904 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1905
1906/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1907PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
1908 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1909PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
1910 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1911PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
1912 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1913PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
1914 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1915
1916#endif /* EASY_ACCESS */
1917
1918#ifdef PNG_READ_SUPPORTED
1919/* Returns pointer to signature string read from PNG header */
1920PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
1921 png_const_inforp info_ptr));
1922#endif
1923
1924#ifdef PNG_bKGD_SUPPORTED
1925PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
1926 png_inforp info_ptr, png_color_16p *background));
1927#endif
1928
1929#ifdef PNG_bKGD_SUPPORTED
1930PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
1931 png_inforp info_ptr, png_const_color_16p background));
1932#endif
1933
1934#ifdef PNG_cHRM_SUPPORTED
1935PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
1936 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
1937 double *red_y, double *green_x, double *green_y, double *blue_x,
1938 double *blue_y))
1939PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
1940 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
1941 double *green_X, double *green_Y, double *green_Z, double *blue_X,
1942 double *blue_Y, double *blue_Z))
1943PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
1944 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1945 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
1946 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
1947 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
1948 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
1949PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
1950 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1951 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
1952 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
1953 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
1954 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
1955 png_fixed_point *int_blue_Z))
1956#endif
1957
1958#ifdef PNG_cHRM_SUPPORTED
1959PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
1960 png_inforp info_ptr,
1961 double white_x, double white_y, double red_x, double red_y, double green_x,
1962 double green_y, double blue_x, double blue_y))
1963PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
1964 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
1965 double green_X, double green_Y, double green_Z, double blue_X,
1966 double blue_Y, double blue_Z))
1967PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
1968 png_inforp info_ptr, png_fixed_point int_white_x,
1969 png_fixed_point int_white_y, png_fixed_point int_red_x,
1970 png_fixed_point int_red_y, png_fixed_point int_green_x,
1971 png_fixed_point int_green_y, png_fixed_point int_blue_x,
1972 png_fixed_point int_blue_y))
1973PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
1974 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
1975 png_fixed_point int_red_Z, png_fixed_point int_green_X,
1976 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
1977 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
1978 png_fixed_point int_blue_Z))
1979#endif
1980
1981#ifdef PNG_eXIf_SUPPORTED
1982PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
1983 png_inforp info_ptr, png_bytep *exif));
1984PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr,
1985 png_inforp info_ptr, png_bytep exif));
1986
1987PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr,
1988 png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif));
1989PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr,
1990 png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif));
1991#endif
1992
1993#ifdef PNG_gAMA_SUPPORTED
1994PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
1995 png_const_inforp info_ptr, double *file_gamma))
1996PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
1997 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1998 png_fixed_point *int_file_gamma))
1999#endif
2000
2001#ifdef PNG_gAMA_SUPPORTED
2002PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2003 png_inforp info_ptr, double file_gamma))
2004PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2005 png_inforp info_ptr, png_fixed_point int_file_gamma))
2006#endif
2007
2008#ifdef PNG_hIST_SUPPORTED
2009PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2010 png_inforp info_ptr, png_uint_16p *hist));
2011PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2012 png_inforp info_ptr, png_const_uint_16p hist));
2013#endif
2014
2015PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2016 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2017 int *bit_depth, int *color_type, int *interlace_method,
2018 int *compression_method, int *filter_method));
2019
2020PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2021 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2022 int color_type, int interlace_method, int compression_method,
2023 int filter_method));
2024
2025#ifdef PNG_oFFs_SUPPORTED
2026PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2027 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2028 int *unit_type));
2029#endif
2030
2031#ifdef PNG_oFFs_SUPPORTED
2032PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2033 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2034 int unit_type));
2035#endif
2036
2037#ifdef PNG_pCAL_SUPPORTED
2038PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2039 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2040 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2041 png_charpp *params));
2042#endif
2043
2044#ifdef PNG_pCAL_SUPPORTED
2045PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2046 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2047 int type, int nparams, png_const_charp units, png_charpp params));
2048#endif
2049
2050#ifdef PNG_pHYs_SUPPORTED
2051PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2052 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2053 int *unit_type));
2054#endif
2055
2056#ifdef PNG_pHYs_SUPPORTED
2057PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2058 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2059#endif
2060
2061PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2062 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2063
2064PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2065 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2066
2067#ifdef PNG_sBIT_SUPPORTED
2068PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2069 png_inforp info_ptr, png_color_8p *sig_bit));
2070#endif
2071
2072#ifdef PNG_sBIT_SUPPORTED
2073PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2074 png_inforp info_ptr, png_const_color_8p sig_bit));
2075#endif
2076
2077#ifdef PNG_sRGB_SUPPORTED
2078PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2079 png_const_inforp info_ptr, int *file_srgb_intent));
2080#endif
2081
2082#ifdef PNG_sRGB_SUPPORTED
2083PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2084 png_inforp info_ptr, int srgb_intent));
2085PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2086 png_inforp info_ptr, int srgb_intent));
2087#endif
2088
2089#ifdef PNG_iCCP_SUPPORTED
2090PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2091 png_inforp info_ptr, png_charpp name, int *compression_type,
2092 png_bytepp profile, png_uint_32 *proflen));
2093#endif
2094
2095#ifdef PNG_iCCP_SUPPORTED
2096PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2097 png_inforp info_ptr, png_const_charp name, int compression_type,
2098 png_const_bytep profile, png_uint_32 proflen));
2099#endif
2100
2101#ifdef PNG_sPLT_SUPPORTED
2102PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2103 png_inforp info_ptr, png_sPLT_tpp entries));
2104#endif
2105
2106#ifdef PNG_sPLT_SUPPORTED
2107PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2108 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2109#endif
2110
2111#ifdef PNG_TEXT_SUPPORTED
2112/* png_get_text also returns the number of text chunks in *num_text */
2113PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2114 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2115#endif
2116
2117/* Note while png_set_text() will accept a structure whose text,
2118 * language, and translated keywords are NULL pointers, the structure
2119 * returned by png_get_text will always contain regular
2120 * zero-terminated C strings. They might be empty strings but
2121 * they will never be NULL pointers.
2122 */
2123
2124#ifdef PNG_TEXT_SUPPORTED
2125PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2126 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2127#endif
2128
2129#ifdef PNG_tIME_SUPPORTED
2130PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2131 png_inforp info_ptr, png_timep *mod_time));
2132#endif
2133
2134#ifdef PNG_tIME_SUPPORTED
2135PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2136 png_inforp info_ptr, png_const_timep mod_time));
2137#endif
2138
2139#ifdef PNG_tRNS_SUPPORTED
2140PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2141 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2142 png_color_16p *trans_color));
2143#endif
2144
2145#ifdef PNG_tRNS_SUPPORTED
2146PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2147 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2148 png_const_color_16p trans_color));
2149#endif
2150
2151#ifdef PNG_sCAL_SUPPORTED
2152PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2153 png_const_inforp info_ptr, int *unit, double *width, double *height))
2154#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2155 defined(PNG_FLOATING_POINT_SUPPORTED)
2156/* NOTE: this API is currently implemented using floating point arithmetic,
2157 * consequently it can only be used on systems with floating point support.
2158 * In any case the range of values supported by png_fixed_point is small and it
2159 * is highly recommended that png_get_sCAL_s be used instead.
2160 */
2161PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2162 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2163 png_fixed_point *width, png_fixed_point *height))
2164#endif
2165PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2166 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2167 png_charpp swidth, png_charpp sheight));
2168
2169PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2170 png_inforp info_ptr, int unit, double width, double height))
2171PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2172 png_inforp info_ptr, int unit, png_fixed_point width,
2173 png_fixed_point height))
2174PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2175 png_inforp info_ptr, int unit,
2176 png_const_charp swidth, png_const_charp sheight));
2177#endif /* sCAL */
2178
2179#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2180/* Provide the default handling for all unknown chunks or, optionally, for
2181 * specific unknown chunks.
2182 *
2183 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2184 * ignored and the default was used, the per-chunk setting only had an effect on
2185 * write. If you wish to have chunk-specific handling on read in code that must
2186 * work on earlier versions you must use a user chunk callback to specify the
2187 * desired handling (keep or discard.)
2188 *
2189 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2190 * parameter is interpreted as follows:
2191 *
2192 * READ:
2193 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2194 * Known chunks: do normal libpng processing, do not keep the chunk (but
2195 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2196 * Unknown chunks: for a specific chunk use the global default, when used
2197 * as the default discard the chunk data.
2198 * PNG_HANDLE_CHUNK_NEVER:
2199 * Discard the chunk data.
2200 * PNG_HANDLE_CHUNK_IF_SAFE:
2201 * Keep the chunk data if the chunk is not critical else raise a chunk
2202 * error.
2203 * PNG_HANDLE_CHUNK_ALWAYS:
2204 * Keep the chunk data.
2205 *
2206 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2207 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2208 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2209 * it simply resets the behavior to the libpng default.
2210 *
2211 * INTERACTION WITH USER CHUNK CALLBACKS:
2212 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2213 * callback and the callback returns 0; the chunk is then always stored *unless*
2214 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2215 * the global default is *not* used in this case. (In effect the per-chunk
2216 * value is incremented to at least IF_SAFE.)
2217 *
2218 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2219 * per-chunk defaults will be honored. If you want to preserve the current
2220 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2221 * as the default - if you don't do this libpng 1.6 will issue a warning.
2222 *
2223 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2224 * earlier simply return '1' (handled).
2225 *
2226 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2227 * If this is *not* set known chunks will always be handled by libpng and
2228 * will never be stored in the unknown chunk list. Known chunks listed to
2229 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2230 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2231 * by libpng, in addition critical chunks must either be processed by the
2232 * callback or saved.
2233 *
2234 * The IHDR and IEND chunks must not be listed. Because this turns off the
2235 * default handling for chunks that would otherwise be recognized the
2236 * behavior of libpng transformations may well become incorrect!
2237 *
2238 * WRITE:
2239 * When writing chunks the options only apply to the chunks specified by
2240 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2241 * required by png_set_ calls and will always write the core critical chunks
2242 * (as required for PLTE).
2243 *
2244 * Each chunk in the png_set_unknown_chunks list is looked up in the
2245 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2246 * interpreted as follows:
2247 *
2248 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2249 * Write safe-to-copy chunks and write other chunks if the global
2250 * default is set to _ALWAYS, otherwise don't write this chunk.
2251 * PNG_HANDLE_CHUNK_NEVER:
2252 * Do not write the chunk.
2253 * PNG_HANDLE_CHUNK_IF_SAFE:
2254 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2255 * PNG_HANDLE_CHUNK_ALWAYS:
2256 * Write the chunk.
2257 *
2258 * Note that the default behavior is effectively the opposite of the read case -
2259 * in read unknown chunks are not stored by default, in write they are written
2260 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2261 * - on write the safe-to-copy bit is checked, on read the critical bit is
2262 * checked and on read if the chunk is critical an error will be raised.
2263 *
2264 * num_chunks:
2265 * ===========
2266 * If num_chunks is positive, then the "keep" parameter specifies the manner
2267 * for handling only those chunks appearing in the chunk_list array,
2268 * otherwise the chunk list array is ignored.
2269 *
2270 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2271 * unknown chunks, as described above.
2272 *
2273 * If num_chunks is negative, then the "keep" parameter specifies the manner
2274 * for handling all unknown chunks plus all chunks recognized by libpng
2275 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2276 * be processed by libpng.
2277 */
2278#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2279PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2280 int keep, png_const_bytep chunk_list, int num_chunks));
2281#endif /* HANDLE_AS_UNKNOWN */
2282
2283/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2284 * the result is therefore true (non-zero) if special handling is required,
2285 * false for the default handling.
2286 */
2287PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2288 png_const_bytep chunk_name));
2289#endif /* SET_UNKNOWN_CHUNKS */
2290
2291#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2292PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2293 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2294 int num_unknowns));
2295 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2296 * unknowns to the location currently stored in the png_struct. This is
2297 * invariably the wrong value on write. To fix this call the following API
2298 * for each chunk in the list with the correct location. If you know your
2299 * code won't be compiled on earlier versions you can rely on
2300 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2301 * the correct thing.
2302 */
2303
2304PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2305 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2306
2307PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2308 png_inforp info_ptr, png_unknown_chunkpp entries));
2309#endif
2310
2311/* Png_free_data() will turn off the "valid" flag for anything it frees.
2312 * If you need to turn it off for a chunk that your application has freed,
2313 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2314 */
2315PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2316 png_inforp info_ptr, int mask));
2317
2318#ifdef PNG_INFO_IMAGE_SUPPORTED
2319/* The "params" pointer is currently not used and is for future expansion. */
2320#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2321PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2322 int transforms, png_voidp params));
2323#endif
2324#ifdef PNG_WRITE_SUPPORTED
2325PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2326 int transforms, png_voidp params));
2327#endif
2328#endif
2329
2330PNG_EXPORT(180, png_const_charp, png_get_copyright,
2331 (png_const_structrp png_ptr));
2332PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2333 (png_const_structrp png_ptr));
2334PNG_EXPORT(182, png_const_charp, png_get_header_version,
2335 (png_const_structrp png_ptr));
2336PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2337 (png_const_structrp png_ptr));
2338
2339#ifdef PNG_MNG_FEATURES_SUPPORTED
2340PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2341 png_uint_32 mng_features_permitted));
2342#endif
2343
2344/* For use in png_set_keep_unknown, added to version 1.2.6 */
2345#define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2346#define PNG_HANDLE_CHUNK_NEVER 1
2347#define PNG_HANDLE_CHUNK_IF_SAFE 2
2348#define PNG_HANDLE_CHUNK_ALWAYS 3
2349#define PNG_HANDLE_CHUNK_LAST 4
2350
2351/* Strip the prepended error numbers ("#nnn ") from error and warning
2352 * messages before passing them to the error or warning handler.
2353 */
2354#ifdef PNG_ERROR_NUMBERS_SUPPORTED
2355PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2356 png_uint_32 strip_mode));
2357#endif
2358
2359/* Added in libpng-1.2.6 */
2360#ifdef PNG_SET_USER_LIMITS_SUPPORTED
2361PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2362 png_uint_32 user_width_max, png_uint_32 user_height_max));
2363PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2364 (png_const_structrp png_ptr));
2365PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2366 (png_const_structrp png_ptr));
2367/* Added in libpng-1.4.0 */
2368PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2369 png_uint_32 user_chunk_cache_max));
2370PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2371 (png_const_structrp png_ptr));
2372/* Added in libpng-1.4.1 */
2373PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2374 png_alloc_size_t user_chunk_cache_max));
2375PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2376 (png_const_structrp png_ptr));
2377#endif
2378
2379#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2380PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2381 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2382
2383PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2384 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2385
2386PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2387 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2388
2389PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2390 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2391#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2392PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2393 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2394#endif
2395
2396PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2397 png_const_inforp info_ptr))
2398#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2399PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2400 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2401#endif
2402
2403# ifdef PNG_pHYs_SUPPORTED
2404PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2405 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2406 int *unit_type));
2407# endif /* pHYs */
2408#endif /* INCH_CONVERSIONS */
2409
2410/* Added in libpng-1.4.0 */
2411#ifdef PNG_IO_STATE_SUPPORTED
2412PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2413
2414/* Removed from libpng 1.6; use png_get_io_chunk_type. */
2415PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2416 PNG_DEPRECATED)
2417
2418PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2419 (png_const_structrp png_ptr));
2420
2421/* The flags returned by png_get_io_state() are the following: */
2422# define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2423# define PNG_IO_READING 0x0001 /* currently reading */
2424# define PNG_IO_WRITING 0x0002 /* currently writing */
2425# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2426# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2427# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2428# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2429# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2430# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2431#endif /* IO_STATE */
2432
2433/* Interlace support. The following macros are always defined so that if
2434 * libpng interlace handling is turned off the macros may be used to handle
2435 * interlaced images within the application.
2436 */
2437#define PNG_INTERLACE_ADAM7_PASSES 7
2438
2439/* Two macros to return the first row and first column of the original,
2440 * full, image which appears in a given pass. 'pass' is in the range 0
2441 * to 6 and the result is in the range 0 to 7.
2442 */
2443#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2444#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2445
2446/* A macro to return the offset between pixels in the output row for a pair of
2447 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2448 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2449 * COL_OFFSET is from one column to the next, within a row.
2450 */
2451#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2452#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2453
2454/* Two macros to help evaluate the number of rows or columns in each
2455 * pass. This is expressed as a shift - effectively log2 of the number or
2456 * rows or columns in each 8x8 tile of the original image.
2457 */
2458#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2459#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2460
2461/* Hence two macros to determine the number of rows or columns in a given
2462 * pass of an image given its height or width. In fact these macros may
2463 * return non-zero even though the sub-image is empty, because the other
2464 * dimension may be empty for a small image.
2465 */
2466#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2467 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2468#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2469 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2470
2471/* For the reader row callbacks (both progressive and sequential) it is
2472 * necessary to find the row in the output image given a row in an interlaced
2473 * image, so two more macros:
2474 */
2475#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2476 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2477#define PNG_COL_FROM_PASS_COL(x_in, pass) \
2478 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2479
2480/* Two macros which return a boolean (0 or 1) saying whether the given row
2481 * or column is in a particular pass. These use a common utility macro that
2482 * returns a mask for a given pass - the offset 'off' selects the row or
2483 * column version. The mask has the appropriate bit set for each column in
2484 * the tile.
2485 */
2486#define PNG_PASS_MASK(pass,off) ( \
2487 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2488 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2489
2490#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2491 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2492#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2493 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2494
2495#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2496/* With these routines we avoid an integer divide, which will be slower on
2497 * most machines. However, it does take more operations than the corresponding
2498 * divide method, so it may be slower on a few RISC systems. There are two
2499 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2500 *
2501 * Note that the rounding factors are NOT supposed to be the same! 128 and
2502 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2503 * standard method.
2504 *
2505 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2506 */
2507
2508 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2509
2510# define png_composite(composite, fg, alpha, bg) \
2511 { \
2512 png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2513 * (png_uint_16)(alpha) \
2514 + (png_uint_16)(bg)*(png_uint_16)(255 \
2515 - (png_uint_16)(alpha)) + 128); \
2516 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
2517 }
2518
2519# define png_composite_16(composite, fg, alpha, bg) \
2520 { \
2521 png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2522 * (png_uint_32)(alpha) \
2523 + (png_uint_32)(bg)*(65535 \
2524 - (png_uint_32)(alpha)) + 32768); \
2525 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
2526 }
2527
2528#else /* Standard method using integer division */
2529
2530# define png_composite(composite, fg, alpha, bg) \
2531 (composite) = \
2532 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2533 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2534 127) / 255))
2535
2536# define png_composite_16(composite, fg, alpha, bg) \
2537 (composite) = \
2538 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2539 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2540 32767) / 65535))
2541#endif /* READ_COMPOSITE_NODIV */
2542
2543#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2544PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2545PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2546PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2547#endif
2548
2549PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2550 png_const_bytep buf));
2551/* No png_get_int_16 -- may be added if there's a real need for it. */
2552
2553/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2554#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2555PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2556#endif
2557#ifdef PNG_SAVE_INT_32_SUPPORTED
2558PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2559#endif
2560
2561/* Place a 16-bit number into a buffer in PNG byte order.
2562 * The parameter is declared unsigned int, not png_uint_16,
2563 * just to avoid potential problems on pre-ANSI C compilers.
2564 */
2565#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2566PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2567/* No png_save_int_16 -- may be added if there's a real need for it. */
2568#endif
2569
2570#ifdef PNG_USE_READ_MACROS
2571/* Inline macros to do direct reads of bytes from the input buffer.
2572 * The png_get_int_32() routine assumes we are using two's complement
2573 * format for negative values, which is almost certainly true.
2574 */
2575# define PNG_get_uint_32(buf) \
2576 (((png_uint_32)(*(buf)) << 24) + \
2577 ((png_uint_32)(*((buf) + 1)) << 16) + \
2578 ((png_uint_32)(*((buf) + 2)) << 8) + \
2579 ((png_uint_32)(*((buf) + 3))))
2580
2581 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2582 * function) incorrectly returned a value of type png_uint_32.
2583 */
2584# define PNG_get_uint_16(buf) \
2585 ((png_uint_16) \
2586 (((unsigned int)(*(buf)) << 8) + \
2587 ((unsigned int)(*((buf) + 1)))))
2588
2589# define PNG_get_int_32(buf) \
2590 ((png_int_32)((*(buf) & 0x80) \
2591 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2592 : (png_int_32)png_get_uint_32(buf)))
2593
2594/* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2595 * but defining a macro name prefixed with PNG_PREFIX.
2596 */
2597# ifndef PNG_PREFIX
2598# define png_get_uint_32(buf) PNG_get_uint_32(buf)
2599# define png_get_uint_16(buf) PNG_get_uint_16(buf)
2600# define png_get_int_32(buf) PNG_get_int_32(buf)
2601# endif
2602#else
2603# ifdef PNG_PREFIX
2604 /* No macros; revert to the (redefined) function */
2605# define PNG_get_uint_32 (png_get_uint_32)
2606# define PNG_get_uint_16 (png_get_uint_16)
2607# define PNG_get_int_32 (png_get_int_32)
2608# endif
2609#endif
2610
2611#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2612PNG_EXPORT(242, void, png_set_check_for_invalid_index,
2613 (png_structrp png_ptr, int allowed));
2614# ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2615PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
2616 png_const_infop info_ptr));
2617# endif
2618#endif /* CHECK_FOR_INVALID_INDEX */
2619
2620/*******************************************************************************
2621 * Section 5: SIMPLIFIED API
2622 *******************************************************************************
2623 *
2624 * Please read the documentation in libpng-manual.txt (TODO: write said
2625 * documentation) if you don't understand what follows.
2626 *
2627 * The simplified API hides the details of both libpng and the PNG file format
2628 * itself. It allows PNG files to be read into a very limited number of
2629 * in-memory bitmap formats or to be written from the same formats. If these
2630 * formats do not accommodate your needs then you can, and should, use the more
2631 * sophisticated APIs above - these support a wide variety of in-memory formats
2632 * and a wide variety of sophisticated transformations to those formats as well
2633 * as a wide variety of APIs to manipulate ancillary information.
2634 *
2635 * To read a PNG file using the simplified API:
2636 *
2637 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2638 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2639 * (this is REQUIRED, your program may crash if you don't do it.)
2640 * 2) Call the appropriate png_image_begin_read... function.
2641 * 3) Set the png_image 'format' member to the required sample format.
2642 * 4) Allocate a buffer for the image and, if required, the color-map.
2643 * 5) Call png_image_finish_read to read the image and, if required, the
2644 * color-map into your buffers.
2645 *
2646 * There are no restrictions on the format of the PNG input itself; all valid
2647 * color types, bit depths, and interlace methods are acceptable, and the
2648 * input image is transformed as necessary to the requested in-memory format
2649 * during the png_image_finish_read() step. The only caveat is that if you
2650 * request a color-mapped image from a PNG that is full-color or makes
2651 * complex use of an alpha channel the transformation is extremely lossy and the
2652 * result may look terrible.
2653 *
2654 * To write a PNG file using the simplified API:
2655 *
2656 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2657 * 2) Initialize the members of the structure that describe the image, setting
2658 * the 'format' member to the format of the image samples.
2659 * 3) Call the appropriate png_image_write... function with a pointer to the
2660 * image and, if necessary, the color-map to write the PNG data.
2661 *
2662 * png_image is a structure that describes the in-memory format of an image
2663 * when it is being read or defines the in-memory format of an image that you
2664 * need to write:
2665 */
2666#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2667 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2668
2669#define PNG_IMAGE_VERSION 1
2670
2671typedef struct png_control *png_controlp;
2672typedef struct
2673{
2674 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2675 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2676 png_uint_32 width; /* Image width in pixels (columns) */
2677 png_uint_32 height; /* Image height in pixels (rows) */
2678 png_uint_32 format; /* Image format as defined below */
2679 png_uint_32 flags; /* A bit mask containing informational flags */
2680 png_uint_32 colormap_entries;
2681 /* Number of entries in the color-map */
2682
2683 /* In the event of an error or warning the following field will be set to a
2684 * non-zero value and the 'message' field will contain a '\0' terminated
2685 * string with the libpng error or warning message. If both warnings and
2686 * an error were encountered, only the error is recorded. If there
2687 * are multiple warnings, only the first one is recorded.
2688 *
2689 * The upper 30 bits of this value are reserved, the low two bits contain
2690 * a value as follows:
2691 */
2692# define PNG_IMAGE_WARNING 1
2693# define PNG_IMAGE_ERROR 2
2694 /*
2695 * The result is a two-bit code such that a value more than 1 indicates
2696 * a failure in the API just called:
2697 *
2698 * 0 - no warning or error
2699 * 1 - warning
2700 * 2 - error
2701 * 3 - error preceded by warning
2702 */
2703# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2704
2705 png_uint_32 warning_or_error;
2706
2707 char message[64];
2708} png_image, *png_imagep;
2709
2710/* The samples of the image have one to four channels whose components have
2711 * original values in the range 0 to 1.0:
2712 *
2713 * 1: A single gray or luminance channel (G).
2714 * 2: A gray/luminance channel and an alpha channel (GA).
2715 * 3: Three red, green, blue color channels (RGB).
2716 * 4: Three color channels and an alpha channel (RGBA).
2717 *
2718 * The components are encoded in one of two ways:
2719 *
2720 * a) As a small integer, value 0..255, contained in a single byte. For the
2721 * alpha channel the original value is simply value/255. For the color or
2722 * luminance channels the value is encoded according to the sRGB specification
2723 * and matches the 8-bit format expected by typical display devices.
2724 *
2725 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2726 * channel and are suitable for passing to color management software.
2727 *
2728 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2729 * channels can be converted to the original value by dividing by 65535; all
2730 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2731 * the sRGB specification. This encoding is identified by the
2732 * PNG_FORMAT_FLAG_LINEAR flag below.
2733 *
2734 * When the simplified API needs to convert between sRGB and linear colorspaces,
2735 * the actual sRGB transfer curve defined in the sRGB specification (see the
2736 * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2
2737 * approximation used elsewhere in libpng.
2738 *
2739 * When an alpha channel is present it is expected to denote pixel coverage
2740 * of the color or luminance channels and is returned as an associated alpha
2741 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2742 * value.
2743 *
2744 * The samples are either contained directly in the image data, between 1 and 8
2745 * bytes per pixel according to the encoding, or are held in a color-map indexed
2746 * by bytes in the image data. In the case of a color-map the color-map entries
2747 * are individual samples, encoded as above, and the image data has one byte per
2748 * pixel to select the relevant sample from the color-map.
2749 */
2750
2751/* PNG_FORMAT_*
2752 *
2753 * #defines to be used in png_image::format. Each #define identifies a
2754 * particular layout of sample data and, if present, alpha values. There are
2755 * separate defines for each of the two component encodings.
2756 *
2757 * A format is built up using single bit flag values. All combinations are
2758 * valid. Formats can be built up from the flag values or you can use one of
2759 * the predefined values below. When testing formats always use the FORMAT_FLAG
2760 * macros to test for individual features - future versions of the library may
2761 * add new flags.
2762 *
2763 * When reading or writing color-mapped images the format should be set to the
2764 * format of the entries in the color-map then png_image_{read,write}_colormap
2765 * called to read or write the color-map and set the format correctly for the
2766 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2767 *
2768 * NOTE: libpng can be built with particular features disabled. If you see
2769 * compiler errors because the definition of one of the following flags has been
2770 * compiled out it is because libpng does not have the required support. It is
2771 * possible, however, for the libpng configuration to enable the format on just
2772 * read or just write; in that case you may see an error at run time. You can
2773 * guard against this by checking for the definition of the appropriate
2774 * "_SUPPORTED" macro, one of:
2775 *
2776 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2777 */
2778#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2779#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2780#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2781#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2782
2783#ifdef PNG_FORMAT_BGR_SUPPORTED
2784# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2785#endif
2786
2787#ifdef PNG_FORMAT_AFIRST_SUPPORTED
2788# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2789#endif
2790
2791#define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */
2792
2793/* Commonly used formats have predefined macros.
2794 *
2795 * First the single byte (sRGB) formats:
2796 */
2797#define PNG_FORMAT_GRAY 0
2798#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2799#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2800#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2801#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2802#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2803#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2804#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2805#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2806
2807/* Then the linear 2-byte formats. When naming these "Y" is used to
2808 * indicate a luminance (gray) channel.
2809 */
2810#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2811#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2812#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2813#define PNG_FORMAT_LINEAR_RGB_ALPHA \
2814 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2815
2816/* With color-mapped formats the image data is one byte for each pixel, the byte
2817 * is an index into the color-map which is formatted as above. To obtain a
2818 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2819 * to one of the above definitions, or you can use one of the definitions below.
2820 */
2821#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2822#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2823#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2824#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2825#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2826#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2827
2828/* PNG_IMAGE macros
2829 *
2830 * These are convenience macros to derive information from a png_image
2831 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2832 * actual image sample values - either the entries in the color-map or the
2833 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2834 * for the pixels and will always return 1 for color-mapped formats. The
2835 * remaining macros return information about the rows in the image and the
2836 * complete image.
2837 *
2838 * NOTE: All the macros that take a png_image::format parameter are compile time
2839 * constants if the format parameter is, itself, a constant. Therefore these
2840 * macros can be used in array declarations and case labels where required.
2841 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2842 * they can be used in #if tests.
2843 *
2844 * First the information about the samples.
2845 */
2846#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2847 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2848 /* Return the total number of channels in a given format: 1..4 */
2849
2850#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2851 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2852 /* Return the size in bytes of a single component of a pixel or color-map
2853 * entry (as appropriate) in the image: 1 or 2.
2854 */
2855
2856#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2857 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2858 /* This is the size of the sample data for one sample. If the image is
2859 * color-mapped it is the size of one color-map entry (and image pixels are
2860 * one byte in size), otherwise it is the size of one image pixel.
2861 */
2862
2863#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2864 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2865 /* The maximum size of the color-map required by the format expressed in a
2866 * count of components. This can be used to compile-time allocate a
2867 * color-map:
2868 *
2869 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2870 *
2871 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2872 *
2873 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2874 * information from one of the png_image_begin_read_ APIs and dynamically
2875 * allocate the required memory.
2876 */
2877
2878/* Corresponding information about the pixels */
2879#define PNG_IMAGE_PIXEL_(test,fmt)\
2880 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2881
2882#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2883 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2884 /* The number of separate channels (components) in a pixel; 1 for a
2885 * color-mapped image.
2886 */
2887
2888#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2889 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2890 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2891 * image.
2892 */
2893
2894#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2895 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2896
2897/* Information about the whole row, or whole image */
2898#define PNG_IMAGE_ROW_STRIDE(image)\
2899 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2900 /* Return the total number of components in a single row of the image; this
2901 * is the minimum 'row stride', the minimum count of components between each
2902 * row. For a color-mapped image this is the minimum number of bytes in a
2903 * row.
2904 *
2905 * WARNING: this macro overflows for some images with more than one component
2906 * and very large image widths. libpng will refuse to process an image where
2907 * this macro would overflow.
2908 */
2909
2910#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2911 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2912 /* Return the size, in bytes, of an image buffer given a png_image and a row
2913 * stride - the number of components to leave space for in each row.
2914 *
2915 * WARNING: this macro overflows a 32-bit integer for some large PNG images,
2916 * libpng will refuse to process an image where such an overflow would occur.
2917 */
2918
2919#define PNG_IMAGE_SIZE(image)\
2920 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2921 /* Return the size, in bytes, of the image in memory given just a png_image;
2922 * the row stride is the minimum stride required for the image.
2923 */
2924
2925#define PNG_IMAGE_COLORMAP_SIZE(image)\
2926 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2927 /* Return the size, in bytes, of the color-map of this image. If the image
2928 * format is not a color-map format this will return a size sufficient for
2929 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2930 * you don't want to allocate a color-map in this case.
2931 */
2932
2933/* PNG_IMAGE_FLAG_*
2934 *
2935 * Flags containing additional information about the image are held in the
2936 * 'flags' field of png_image.
2937 */
2938#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2939 /* This indicates that the RGB values of the in-memory bitmap do not
2940 * correspond to the red, green and blue end-points defined by sRGB.
2941 */
2942
2943#define PNG_IMAGE_FLAG_FAST 0x02
2944 /* On write emphasise speed over compression; the resultant PNG file will be
2945 * larger but will be produced significantly faster, particular for large
2946 * images. Do not use this option for images which will be distributed, only
2947 * used it when producing intermediate files that will be read back in
2948 * repeatedly. For a typical 24-bit image the option will double the read
2949 * speed at the cost of increasing the image size by 25%, however for many
2950 * more compressible images the PNG file can be 10 times larger with only a
2951 * slight speed gain.
2952 */
2953
2954#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
2955 /* On read if the image is a 16-bit per component image and there is no gAMA
2956 * or sRGB chunk assume that the components are sRGB encoded. Notice that
2957 * images output by the simplified API always have gamma information; setting
2958 * this flag only affects the interpretation of 16-bit images from an
2959 * external source. It is recommended that the application expose this flag
2960 * to the user; the user can normally easily recognize the difference between
2961 * linear and sRGB encoding. This flag has no effect on write - the data
2962 * passed to the write APIs must have the correct encoding (as defined
2963 * above.)
2964 *
2965 * If the flag is not set (the default) input 16-bit per component data is
2966 * assumed to be linear.
2967 *
2968 * NOTE: the flag can only be set after the png_image_begin_read_ call,
2969 * because that call initializes the 'flags' field.
2970 */
2971
2972#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
2973/* READ APIs
2974 * ---------
2975 *
2976 * The png_image passed to the read APIs must have been initialized by setting
2977 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
2978 */
2979#ifdef PNG_STDIO_SUPPORTED
2980PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
2981 const char *file_name));
2982 /* The named file is opened for read and the image header is filled in
2983 * from the PNG header in the file.
2984 */
2985
2986PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
2987 FILE* file));
2988 /* The PNG header is read from the stdio FILE object. */
2989#endif /* STDIO */
2990
2991PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
2992 png_const_voidp memory, size_t size));
2993 /* The PNG header is read from the given memory buffer. */
2994
2995PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
2996 png_const_colorp background, void *buffer, png_int_32 row_stride,
2997 void *colormap));
2998 /* Finish reading the image into the supplied buffer and clean up the
2999 * png_image structure.
3000 *
3001 * row_stride is the step, in byte or 2-byte units as appropriate,
3002 * between adjacent rows. A positive stride indicates that the top-most row
3003 * is first in the buffer - the normal top-down arrangement. A negative
3004 * stride indicates that the bottom-most row is first in the buffer.
3005 *
3006 * background need only be supplied if an alpha channel must be removed from
3007 * a png_byte format and the removal is to be done by compositing on a solid
3008 * color; otherwise it may be NULL and any composition will be done directly
3009 * onto the buffer. The value is an sRGB color to use for the background,
3010 * for grayscale output the green channel is used.
3011 *
3012 * background must be supplied when an alpha channel must be removed from a
3013 * single byte color-mapped output format, in other words if:
3014 *
3015 * 1) The original format from png_image_begin_read_from_* had
3016 * PNG_FORMAT_FLAG_ALPHA set.
3017 * 2) The format set by the application does not.
3018 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3019 * PNG_FORMAT_FLAG_LINEAR *not* set.
3020 *
3021 * For linear output removing the alpha channel is always done by compositing
3022 * on black and background is ignored.
3023 *
3024 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3025 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3026 * image->colormap_entries will be updated to the actual number of entries
3027 * written to the colormap; this may be less than the original value.
3028 */
3029
3030PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3031 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3032 * NULL. May be called at any time after the structure is initialized.
3033 */
3034#endif /* SIMPLIFIED_READ */
3035
3036#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3037/* WRITE APIS
3038 * ----------
3039 * For write you must initialize a png_image structure to describe the image to
3040 * be written. To do this use memset to set the whole structure to 0 then
3041 * initialize fields describing your image.
3042 *
3043 * version: must be set to PNG_IMAGE_VERSION
3044 * opaque: must be initialized to NULL
3045 * width: image width in pixels
3046 * height: image height in rows
3047 * format: the format of the data (image and color-map) you wish to write
3048 * flags: set to 0 unless one of the defined flags applies; set
3049 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3050 * values do not correspond to the colors in sRGB.
3051 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3052 */
3053#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3054PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3055 const char *file, int convert_to_8bit, const void *buffer,
3056 png_int_32 row_stride, const void *colormap));
3057 /* Write the image to the named file. */
3058
3059PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3060 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3061 const void *colormap));
3062 /* Write the image to the given (FILE*). */
3063#endif /* SIMPLIFIED_WRITE_STDIO */
3064
3065/* With all write APIs if image is in one of the linear formats with 16-bit
3066 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3067 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3068 * encoded PNG file is written.
3069 *
3070 * With color-mapped data formats the colormap parameter point to a color-map
3071 * with at least image->colormap_entries encoded in the specified format. If
3072 * the format is linear the written PNG color-map will be converted to sRGB
3073 * regardless of the convert_to_8_bit flag.
3074 *
3075 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3076 * from one row to the next in component sized units (1 or 2 bytes) and if
3077 * negative indicates a bottom-up row layout in the buffer. If row_stride is
3078 * zero, libpng will calculate it for you from the image width and number of
3079 * channels.
3080 *
3081 * Note that the write API does not support interlacing, sub-8-bit pixels or
3082 * most ancillary chunks. If you need to write text chunks (e.g. for copyright
3083 * notices) you need to use one of the other APIs.
3084 */
3085
3086PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
3087 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
3088 const void *buffer, png_int_32 row_stride, const void *colormap));
3089 /* Write the image to the given memory buffer. The function both writes the
3090 * whole PNG data stream to *memory and updates *memory_bytes with the count
3091 * of bytes written.
3092 *
3093 * 'memory' may be NULL. In this case *memory_bytes is not read however on
3094 * success the number of bytes which would have been written will still be
3095 * stored in *memory_bytes. On failure *memory_bytes will contain 0.
3096 *
3097 * If 'memory' is not NULL it must point to memory[*memory_bytes] of
3098 * writeable memory.
3099 *
3100 * If the function returns success memory[*memory_bytes] (if 'memory' is not
3101 * NULL) contains the written PNG data. *memory_bytes will always be less
3102 * than or equal to the original value.
3103 *
3104 * If the function returns false and *memory_bytes was not changed an error
3105 * occurred during write. If *memory_bytes was changed, or is not 0 if
3106 * 'memory' was NULL, the write would have succeeded but for the memory
3107 * buffer being too small. *memory_bytes contains the required number of
3108 * bytes and will be bigger that the original value.
3109 */
3110
3111#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
3112 row_stride, colormap)\
3113 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
3114 row_stride, colormap)
3115 /* Return the amount of memory in 'size' required to compress this image.
3116 * The png_image structure 'image' must be filled in as in the above
3117 * function and must not be changed before the actual write call, the buffer
3118 * and all other parameters must also be identical to that in the final
3119 * write call. The 'size' variable need not be initialized.
3120 *
3121 * NOTE: the macro returns true/false, if false is returned 'size' will be
3122 * set to zero and the write failed and probably will fail if tried again.
3123 */
3124
3125/* You can pre-allocate the buffer by making sure it is of sufficient size
3126 * regardless of the amount of compression achieved. The buffer size will
3127 * always be bigger than the original image and it will never be filled. The
3128 * following macros are provided to assist in allocating the buffer.
3129 */
3130#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
3131 /* The number of uncompressed bytes in the PNG byte encoding of the image;
3132 * uncompressing the PNG IDAT data will give this number of bytes.
3133 *
3134 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
3135 * macro can because of the extra bytes used in the PNG byte encoding. You
3136 * need to avoid this macro if your image size approaches 2^30 in width or
3137 * height. The same goes for the remainder of these macros; they all produce
3138 * bigger numbers than the actual in-memory image size.
3139 */
3140#ifndef PNG_ZLIB_MAX_SIZE
3141# define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
3142 /* An upper bound on the number of compressed bytes given 'b' uncompressed
3143 * bytes. This is based on deflateBounds() in zlib; different
3144 * implementations of zlib compression may conceivably produce more data so
3145 * if your zlib implementation is not zlib itself redefine this macro
3146 * appropriately.
3147 */
3148#endif
3149
3150#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
3151 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
3152 /* An upper bound on the size of the data in the PNG IDAT chunks. */
3153
3154#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
3155 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
3156 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
3157 12U+3U*(image).colormap_entries/*PLTE data*/+\
3158 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
3159 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
3160 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
3161 /* A helper for the following macro; if your compiler cannot handle the
3162 * following macro use this one with the result of
3163 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
3164 * compilers should handle this just fine.)
3165 */
3166
3167#define PNG_IMAGE_PNG_SIZE_MAX(image)\
3168 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
3169 /* An upper bound on the total length of the PNG data stream for 'image'.
3170 * The result is of type png_alloc_size_t, on 32-bit systems this may
3171 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
3172 * run out of buffer space but return a corrected size which should work.
3173 */
3174#endif /* SIMPLIFIED_WRITE */
3175/*******************************************************************************
3176 * END OF SIMPLIFIED API
3177 ******************************************************************************/
3178#endif /* SIMPLIFIED_{READ|WRITE} */
3179
3180/*******************************************************************************
3181 * Section 6: IMPLEMENTATION OPTIONS
3182 *******************************************************************************
3183 *
3184 * Support for arbitrary implementation-specific optimizations. The API allows
3185 * particular options to be turned on or off. 'Option' is the number of the
3186 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3187 * by the PNG_OPTION_ defines below.
3188 *
3189 * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions,
3190 * are detected at run time, however sometimes it may be impossible
3191 * to do this in user mode, in which case it is necessary to discover
3192 * the capabilities in an OS specific way. Such capabilities are
3193 * listed here when libpng has support for them and must be turned
3194 * ON by the application if present.
3195 *
3196 * SOFTWARE: sometimes software optimizations actually result in performance
3197 * decrease on some architectures or systems, or with some sets of
3198 * PNG images. 'Software' options allow such optimizations to be
3199 * selected at run time.
3200 */
3201#ifdef PNG_SET_OPTION_SUPPORTED
3202#ifdef PNG_ARM_NEON_API_SUPPORTED
3203# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3204#endif
3205#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3206#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3207#ifdef PNG_MIPS_MSA_API_SUPPORTED
3208# define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */
3209#endif
3210#define PNG_IGNORE_ADLER32 8
3211#ifdef PNG_POWERPC_VSX_API_SUPPORTED
3212# define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions supported */
3213#endif
3214#define PNG_OPTION_NEXT 12 /* Next option - numbers must be even */
3215
3216/* Return values: NOTE: there are four values and 'off' is *not* zero */
3217#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3218#define PNG_OPTION_INVALID 1 /* Option number out of range */
3219#define PNG_OPTION_OFF 2
3220#define PNG_OPTION_ON 3
3221
3222PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3223 int onoff));
3224#endif /* SET_OPTION */
3225
3226/*******************************************************************************
3227 * END OF HARDWARE AND SOFTWARE OPTIONS
3228 ******************************************************************************/
3229
3230/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3231 * defs, and in scripts/symbols.def.
3232 */
3233
3234/* The last ordinal number (this is the *last* one already used; the next
3235 * one to use is one more than this.)
3236 */
3237#ifdef PNG_EXPORT_LAST_ORDINAL
3238 PNG_EXPORT_LAST_ORDINAL(249);
3239#endif
3240
3241#ifdef __cplusplus
3242}
3243#endif
3244
3245#endif /* PNG_VERSION_INFO_ONLY */
3246/* Do not put anything past this line */
3247#endif /* PNG_H */
3248

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