1
2/* png.h - header file for PNG reference library
3 *
4 * libpng version 1.6.43
5 *
6 * Copyright (c) 2018-2024 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 1.6.43, February 2024:
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) 1995-2024 The PNG Reference Library Authors.
31 * * Copyright (c) 2018-2024 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 * 1.6.43 16 10643 16.so.16.43[.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 * See libpng.txt or libpng.3 for more information. The PNG specification
259 * is available as a W3C Recommendation and as an ISO/IEC Standard; see
260 * <https://www.w3.org/TR/2003/REC-PNG-20031110/>
261 */
262
263#ifndef PNG_H
264#define PNG_H
265
266/* This is not the place to learn how to use libpng. The file libpng-manual.txt
267 * describes how to use libpng, and the file example.c summarizes it
268 * with some code on which to build. This file is useful for looking
269 * at the actual function definitions and structure components. If that
270 * file has been stripped from your copy of libpng, you can find it at
271 * <http://www.libpng.org/pub/png/libpng-manual.txt>
272 *
273 * If you just need to read a PNG file and don't want to read the documentation
274 * skip to the end of this file and read the section entitled 'simplified API'.
275 */
276
277/* Version information for png.h - this should match the version in png.c */
278#define PNG_LIBPNG_VER_STRING "1.6.43"
279#define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
280
281/* The versions of shared library builds should stay in sync, going forward */
282#define PNG_LIBPNG_VER_SHAREDLIB 16
283#define PNG_LIBPNG_VER_SONUM PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
284#define PNG_LIBPNG_VER_DLLNUM PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
285
286/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
287#define PNG_LIBPNG_VER_MAJOR 1
288#define PNG_LIBPNG_VER_MINOR 6
289#define PNG_LIBPNG_VER_RELEASE 43
290
291/* This should be zero for a public release, or non-zero for a
292 * development version.
293 */
294#define PNG_LIBPNG_VER_BUILD 0
295
296/* Release Status */
297#define PNG_LIBPNG_BUILD_ALPHA 1
298#define PNG_LIBPNG_BUILD_BETA 2
299#define PNG_LIBPNG_BUILD_RC 3
300#define PNG_LIBPNG_BUILD_STABLE 4
301#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
302
303/* Release-Specific Flags */
304#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
305 PNG_LIBPNG_BUILD_STABLE only */
306#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
307 PNG_LIBPNG_BUILD_SPECIAL */
308#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
309 PNG_LIBPNG_BUILD_PRIVATE */
310
311#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
312
313/* Careful here. At one time, Guy wanted to use 082, but that
314 * would be octal. We must not include leading zeros.
315 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here
316 * (only version 1.0.0 was mis-numbered 100 instead of 10000).
317 * From version 1.0.1 it is:
318 * XXYYZZ, where XX=major, YY=minor, ZZ=release
319 */
320#define PNG_LIBPNG_VER 10643 /* 1.6.43 */
321
322/* Library configuration: these options cannot be changed after
323 * the library has been built.
324 */
325#ifndef PNGLCONF_H
326/* If pnglibconf.h is missing, you can
327 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
328 */
329# include "pnglibconf.h"
330#endif
331
332#ifndef PNG_VERSION_INFO_ONLY
333/* Machine specific configuration. */
334# include "pngconf.h"
335#endif
336
337/*
338 * Added at libpng-1.2.8
339 *
340 * Ref MSDN: Private as priority over Special
341 * VS_FF_PRIVATEBUILD File *was not* built using standard release
342 * procedures. If this value is given, the StringFileInfo block must
343 * contain a PrivateBuild string.
344 *
345 * VS_FF_SPECIALBUILD File *was* built by the original company using
346 * standard release procedures but is a variation of the standard
347 * file of the same version number. If this value is given, the
348 * StringFileInfo block must contain a SpecialBuild string.
349 */
350
351#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
352# define PNG_LIBPNG_BUILD_TYPE \
353 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
354#else
355# ifdef PNG_LIBPNG_SPECIALBUILD
356# define PNG_LIBPNG_BUILD_TYPE \
357 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
358# else
359# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
360# endif
361#endif
362
363#ifndef PNG_VERSION_INFO_ONLY
364
365/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
366#ifdef __cplusplus
367extern "C" {
368#endif /* __cplusplus */
369
370/* Version information for C files, stored in png.c. This had better match
371 * the version above.
372 */
373#define png_libpng_ver png_get_header_ver(NULL)
374
375/* This file is arranged in several sections:
376 *
377 * 1. [omitted]
378 * 2. Any configuration options that can be specified by for the application
379 * code when it is built. (Build time configuration is in pnglibconf.h)
380 * 3. Type definitions (base types are defined in pngconf.h), structure
381 * definitions.
382 * 4. Exported library functions.
383 * 5. Simplified API.
384 * 6. Implementation options.
385 *
386 * The library source code has additional files (principally pngpriv.h) that
387 * allow configuration of the library.
388 */
389
390/* Section 1: [omitted] */
391
392/* Section 2: run time configuration
393 * See pnglibconf.h for build time configuration
394 *
395 * Run time configuration allows the application to choose between
396 * implementations of certain arithmetic APIs. The default is set
397 * at build time and recorded in pnglibconf.h, but it is safe to
398 * override these (and only these) settings. Note that this won't
399 * change what the library does, only application code, and the
400 * settings can (and probably should) be made on a per-file basis
401 * by setting the #defines before including png.h
402 *
403 * Use macros to read integers from PNG data or use the exported
404 * functions?
405 * PNG_USE_READ_MACROS: use the macros (see below) Note that
406 * the macros evaluate their argument multiple times.
407 * PNG_NO_USE_READ_MACROS: call the relevant library function.
408 *
409 * Use the alternative algorithm for compositing alpha samples that
410 * does not use division?
411 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
412 * algorithm.
413 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
414 *
415 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
416 * false?
417 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
418 * APIs to png_warning.
419 * Otherwise the calls are mapped to png_error.
420 */
421
422/* Section 3: type definitions, including structures and compile time
423 * constants.
424 * See pngconf.h for base types that vary by machine/system
425 */
426
427/* This triggers a compiler error in png.c, if png.c and png.h
428 * do not agree upon the version number.
429 */
430typedef char* png_libpng_version_1_6_43;
431
432/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
433 *
434 * png_struct is the cache of information used while reading or writing a single
435 * PNG file. One of these is always required, although the simplified API
436 * (below) hides the creation and destruction of it.
437 */
438typedef struct png_struct_def png_struct;
439typedef const png_struct * png_const_structp;
440typedef png_struct * png_structp;
441typedef png_struct * * png_structpp;
442
443/* png_info contains information read from or to be written to a PNG file. One
444 * or more of these must exist while reading or creating a PNG file. The
445 * information is not used by libpng during read but is used to control what
446 * gets written when a PNG file is created. "png_get_" function calls read
447 * information during read and "png_set_" functions calls write information
448 * when creating a PNG.
449 * been moved into a separate header file that is not accessible to
450 * applications. Read libpng-manual.txt or libpng.3 for more info.
451 */
452typedef struct png_info_def png_info;
453typedef png_info * png_infop;
454typedef const png_info * png_const_infop;
455typedef png_info * * png_infopp;
456
457/* Types with names ending 'p' are pointer types. The corresponding types with
458 * names ending 'rp' are identical pointer types except that the pointer is
459 * marked 'restrict', which means that it is the only pointer to the object
460 * passed to the function. Applications should not use the 'restrict' types;
461 * it is always valid to pass 'p' to a pointer with a function argument of the
462 * corresponding 'rp' type. Different compilers have different rules with
463 * regard to type matching in the presence of 'restrict'. For backward
464 * compatibility libpng callbacks never have 'restrict' in their parameters and,
465 * consequentially, writing portable application code is extremely difficult if
466 * an attempt is made to use 'restrict'.
467 */
468typedef png_struct * PNG_RESTRICT png_structrp;
469typedef const png_struct * PNG_RESTRICT png_const_structrp;
470typedef png_info * PNG_RESTRICT png_inforp;
471typedef const png_info * PNG_RESTRICT png_const_inforp;
472
473/* Three color definitions. The order of the red, green, and blue, (and the
474 * exact size) is not important, although the size of the fields need to
475 * be png_byte or png_uint_16 (as defined below).
476 */
477typedef struct png_color_struct
478{
479 png_byte red;
480 png_byte green;
481 png_byte blue;
482} png_color;
483typedef png_color * png_colorp;
484typedef const png_color * png_const_colorp;
485typedef png_color * * png_colorpp;
486
487typedef struct png_color_16_struct
488{
489 png_byte index; /* used for palette files */
490 png_uint_16 red; /* for use in red green blue files */
491 png_uint_16 green;
492 png_uint_16 blue;
493 png_uint_16 gray; /* for use in grayscale files */
494} png_color_16;
495typedef png_color_16 * png_color_16p;
496typedef const png_color_16 * png_const_color_16p;
497typedef png_color_16 * * png_color_16pp;
498
499typedef struct png_color_8_struct
500{
501 png_byte red; /* for use in red green blue files */
502 png_byte green;
503 png_byte blue;
504 png_byte gray; /* for use in grayscale files */
505 png_byte alpha; /* for alpha channel files */
506} png_color_8;
507typedef png_color_8 * png_color_8p;
508typedef const png_color_8 * png_const_color_8p;
509typedef png_color_8 * * png_color_8pp;
510
511/*
512 * The following two structures are used for the in-core representation
513 * of sPLT chunks.
514 */
515typedef struct png_sPLT_entry_struct
516{
517 png_uint_16 red;
518 png_uint_16 green;
519 png_uint_16 blue;
520 png_uint_16 alpha;
521 png_uint_16 frequency;
522} png_sPLT_entry;
523typedef png_sPLT_entry * png_sPLT_entryp;
524typedef const png_sPLT_entry * png_const_sPLT_entryp;
525typedef png_sPLT_entry * * png_sPLT_entrypp;
526
527/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
528 * occupy the LSB of their respective members, and the MSB of each member
529 * is zero-filled. The frequency member always occupies the full 16 bits.
530 */
531
532typedef struct png_sPLT_struct
533{
534 png_charp name; /* palette name */
535 png_byte depth; /* depth of palette samples */
536 png_sPLT_entryp entries; /* palette entries */
537 png_int_32 nentries; /* number of palette entries */
538} png_sPLT_t;
539typedef png_sPLT_t * png_sPLT_tp;
540typedef const png_sPLT_t * png_const_sPLT_tp;
541typedef png_sPLT_t * * png_sPLT_tpp;
542
543#ifdef PNG_TEXT_SUPPORTED
544/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
545 * and whether that contents is compressed or not. The "key" field
546 * points to a regular zero-terminated C string. The "text" fields can be a
547 * regular C string, an empty string, or a NULL pointer.
548 * However, the structure returned by png_get_text() will always contain
549 * the "text" field as a regular zero-terminated C string (possibly
550 * empty), never a NULL pointer, so it can be safely used in printf() and
551 * other string-handling functions. Note that the "itxt_length", "lang", and
552 * "lang_key" members of the structure only exist when the library is built
553 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
554 * default without iTXt support. Also note that when iTXt *is* supported,
555 * the "lang" and "lang_key" fields contain NULL pointers when the
556 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
557 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
558 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
559 * which is always 0 or 1, or its "compression method" which is always 0.
560 */
561typedef struct png_text_struct
562{
563 int compression; /* compression value:
564 -1: tEXt, none
565 0: zTXt, deflate
566 1: iTXt, none
567 2: iTXt, deflate */
568 png_charp key; /* keyword, 1-79 character description of "text" */
569 png_charp text; /* comment, may be an empty string (ie "")
570 or a NULL pointer */
571 size_t text_length; /* length of the text string */
572 size_t itxt_length; /* length of the itxt string */
573 png_charp lang; /* language code, 0-79 characters
574 or a NULL pointer */
575 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
576 chars or a NULL pointer */
577} png_text;
578typedef png_text * png_textp;
579typedef const png_text * png_const_textp;
580typedef png_text * * png_textpp;
581#endif
582
583/* Supported compression types for text in PNG files (tEXt, and zTXt).
584 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
585#define PNG_TEXT_COMPRESSION_NONE_WR -3
586#define PNG_TEXT_COMPRESSION_zTXt_WR -2
587#define PNG_TEXT_COMPRESSION_NONE -1
588#define PNG_TEXT_COMPRESSION_zTXt 0
589#define PNG_ITXT_COMPRESSION_NONE 1
590#define PNG_ITXT_COMPRESSION_zTXt 2
591#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
592
593/* png_time is a way to hold the time in an machine independent way.
594 * Two conversions are provided, both from time_t and struct tm. There
595 * is no portable way to convert to either of these structures, as far
596 * as I know. If you know of a portable way, send it to me. As a side
597 * note - PNG has always been Year 2000 compliant!
598 */
599typedef struct png_time_struct
600{
601 png_uint_16 year; /* full year, as in, 1995 */
602 png_byte month; /* month of year, 1 - 12 */
603 png_byte day; /* day of month, 1 - 31 */
604 png_byte hour; /* hour of day, 0 - 23 */
605 png_byte minute; /* minute of hour, 0 - 59 */
606 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
607} png_time;
608typedef png_time * png_timep;
609typedef const png_time * png_const_timep;
610typedef png_time * * png_timepp;
611
612#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
613 defined(PNG_USER_CHUNKS_SUPPORTED)
614/* png_unknown_chunk is a structure to hold queued chunks for which there is
615 * no specific support. The idea is that we can use this to queue
616 * up private chunks for output even though the library doesn't actually
617 * know about their semantics.
618 *
619 * The data in the structure is set by libpng on read and used on write.
620 */
621typedef struct png_unknown_chunk_t
622{
623 png_byte name[5]; /* Textual chunk name with '\0' terminator */
624 png_byte *data; /* Data, should not be modified on read! */
625 size_t size;
626
627 /* On write 'location' must be set using the flag values listed below.
628 * Notice that on read it is set by libpng however the values stored have
629 * more bits set than are listed below. Always treat the value as a
630 * bitmask. On write set only one bit - setting multiple bits may cause the
631 * chunk to be written in multiple places.
632 */
633 png_byte location; /* mode of operation at read time */
634}
635png_unknown_chunk;
636
637typedef png_unknown_chunk * png_unknown_chunkp;
638typedef const png_unknown_chunk * png_const_unknown_chunkp;
639typedef png_unknown_chunk * * png_unknown_chunkpp;
640#endif
641
642/* Flag values for the unknown chunk location byte. */
643#define PNG_HAVE_IHDR 0x01
644#define PNG_HAVE_PLTE 0x02
645#define PNG_AFTER_IDAT 0x08
646
647/* Maximum positive integer used in PNG is (2^31)-1 */
648#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
649#define PNG_UINT_32_MAX ((png_uint_32)(-1))
650#define PNG_SIZE_MAX ((size_t)(-1))
651
652/* These are constants for fixed point values encoded in the
653 * PNG specification manner (x100000)
654 */
655#define PNG_FP_1 100000
656#define PNG_FP_HALF 50000
657#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
658#define PNG_FP_MIN (-PNG_FP_MAX)
659
660/* These describe the color_type field in png_info. */
661/* color type masks */
662#define PNG_COLOR_MASK_PALETTE 1
663#define PNG_COLOR_MASK_COLOR 2
664#define PNG_COLOR_MASK_ALPHA 4
665
666/* color types. Note that not all combinations are legal */
667#define PNG_COLOR_TYPE_GRAY 0
668#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
669#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
670#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
671#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
672/* aliases */
673#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
674#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
675
676/* This is for compression type. PNG 1.0-1.2 only define the single type. */
677#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
678#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
679
680/* This is for filter type. PNG 1.0-1.2 only define the single type. */
681#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
682#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
683#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
684
685/* These are for the interlacing type. These values should NOT be changed. */
686#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
687#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
688#define PNG_INTERLACE_LAST 2 /* Not a valid value */
689
690/* These are for the oFFs chunk. These values should NOT be changed. */
691#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
692#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
693#define PNG_OFFSET_LAST 2 /* Not a valid value */
694
695/* These are for the pCAL chunk. These values should NOT be changed. */
696#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
697#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
698#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
699#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
700#define PNG_EQUATION_LAST 4 /* Not a valid value */
701
702/* These are for the sCAL chunk. These values should NOT be changed. */
703#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
704#define PNG_SCALE_METER 1 /* meters per pixel */
705#define PNG_SCALE_RADIAN 2 /* radians per pixel */
706#define PNG_SCALE_LAST 3 /* Not a valid value */
707
708/* These are for the pHYs chunk. These values should NOT be changed. */
709#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
710#define PNG_RESOLUTION_METER 1 /* pixels/meter */
711#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
712
713/* These are for the sRGB chunk. These values should NOT be changed. */
714#define PNG_sRGB_INTENT_PERCEPTUAL 0
715#define PNG_sRGB_INTENT_RELATIVE 1
716#define PNG_sRGB_INTENT_SATURATION 2
717#define PNG_sRGB_INTENT_ABSOLUTE 3
718#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
719
720/* This is for text chunks */
721#define PNG_KEYWORD_MAX_LENGTH 79
722
723/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
724#define PNG_MAX_PALETTE_LENGTH 256
725
726/* These determine if an ancillary chunk's data has been successfully read
727 * from the PNG header, or if the application has filled in the corresponding
728 * data in the info_struct to be written into the output file. The values
729 * of the PNG_INFO_<chunk> defines should NOT be changed.
730 */
731#define PNG_INFO_gAMA 0x0001U
732#define PNG_INFO_sBIT 0x0002U
733#define PNG_INFO_cHRM 0x0004U
734#define PNG_INFO_PLTE 0x0008U
735#define PNG_INFO_tRNS 0x0010U
736#define PNG_INFO_bKGD 0x0020U
737#define PNG_INFO_hIST 0x0040U
738#define PNG_INFO_pHYs 0x0080U
739#define PNG_INFO_oFFs 0x0100U
740#define PNG_INFO_tIME 0x0200U
741#define PNG_INFO_pCAL 0x0400U
742#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
743#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
744#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
745#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
746#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
747#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
748
749/* This is used for the transformation routines, as some of them
750 * change these values for the row. It also should enable using
751 * the routines for other purposes.
752 */
753typedef struct png_row_info_struct
754{
755 png_uint_32 width; /* width of row */
756 size_t rowbytes; /* number of bytes in row */
757 png_byte color_type; /* color type of row */
758 png_byte bit_depth; /* bit depth of row */
759 png_byte channels; /* number of channels (1, 2, 3, or 4) */
760 png_byte pixel_depth; /* bits per pixel (depth * channels) */
761} png_row_info;
762
763typedef png_row_info * png_row_infop;
764typedef png_row_info * * png_row_infopp;
765
766/* These are the function types for the I/O functions and for the functions
767 * that allow the user to override the default I/O functions with his or her
768 * own. The png_error_ptr type should match that of user-supplied warning
769 * and error functions, while the png_rw_ptr type should match that of the
770 * user read/write data functions. Note that the 'write' function must not
771 * modify the buffer it is passed. The 'read' function, on the other hand, is
772 * expected to return the read data in the buffer.
773 */
774typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
775typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
776typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
777typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
778 int));
779typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
780 int));
781
782#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
783typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
784typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
785
786/* The following callback receives png_uint_32 row_number, int pass for the
787 * png_bytep data of the row. When transforming an interlaced image the
788 * row number is the row number within the sub-image of the interlace pass, so
789 * the value will increase to the height of the sub-image (not the full image)
790 * then reset to 0 for the next pass.
791 *
792 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
793 * find the output pixel (x,y) given an interlaced sub-image pixel
794 * (row,col,pass). (See below for these macros.)
795 */
796typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
797 png_uint_32, int));
798#endif
799
800#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
801 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
802typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
803 png_bytep));
804#endif
805
806#ifdef PNG_USER_CHUNKS_SUPPORTED
807typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
808 png_unknown_chunkp));
809#endif
810#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
811/* not used anywhere */
812/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
813#endif
814
815#ifdef PNG_SETJMP_SUPPORTED
816/* This must match the function definition in <setjmp.h>, and the application
817 * must include this before png.h to obtain the definition of jmp_buf. The
818 * function is required to be PNG_NORETURN, but this is not checked. If the
819 * function does return the application will crash via an abort() or similar
820 * system level call.
821 *
822 * If you get a warning here while building the library you may need to make
823 * changes to ensure that pnglibconf.h records the calling convention used by
824 * your compiler. This may be very difficult - try using a different compiler
825 * to build the library!
826 */
827PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
828#endif
829
830/* Transform masks for the high-level interface */
831#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
832#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
833#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
834#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
835#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
836#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
837#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
838#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
839#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
840#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
841#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
842#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
843#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
844/* Added to libpng-1.2.34 */
845#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
846#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
847/* Added to libpng-1.4.0 */
848#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
849/* Added to libpng-1.5.4 */
850#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
851#if ~0U > 0xffffU /* or else this might break on a 16-bit machine */
852#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
853#endif
854
855/* Flags for MNG supported features */
856#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
857#define PNG_FLAG_MNG_FILTER_64 0x04
858#define PNG_ALL_MNG_FEATURES 0x05
859
860/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
861 * this allowed the zlib default functions to be used on Windows
862 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
863 * ignores the first argument) should be completely compatible with the
864 * following.
865 */
866typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
867 png_alloc_size_t));
868typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
869
870/* Section 4: exported functions
871 * Here are the function definitions most commonly used. This is not
872 * the place to find out how to use libpng. See libpng-manual.txt for the
873 * full explanation, see example.c for the summary. This just provides
874 * a simple one line description of the use of each function.
875 *
876 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
877 * pngconf.h and in the *.dfn files in the scripts directory.
878 *
879 * PNG_EXPORT(ordinal, type, name, (args));
880 *
881 * ordinal: ordinal that is used while building
882 * *.def files. The ordinal value is only
883 * relevant when preprocessing png.h with
884 * the *.dfn files for building symbol table
885 * entries, and are removed by pngconf.h.
886 * type: return type of the function
887 * name: function name
888 * args: function arguments, with types
889 *
890 * When we wish to append attributes to a function prototype we use
891 * the PNG_EXPORTA() macro instead.
892 *
893 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
894 *
895 * ordinal, type, name, and args: same as in PNG_EXPORT().
896 * attributes: function attributes
897 */
898
899/* Returns the version number of the library */
900PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
901
902/* Tell lib we have already handled the first <num_bytes> magic bytes.
903 * Handling more than 8 bytes from the beginning of the file is an error.
904 */
905PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
906
907/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
908 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
909 * signature, and non-zero otherwise. Having num_to_check == 0 or
910 * start > 7 will always fail (i.e. return non-zero).
911 */
912PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
913 size_t num_to_check));
914
915/* Simple signature checking function. This is the same as calling
916 * png_check_sig(sig, n) := (png_sig_cmp(sig, 0, n) == 0).
917 */
918#define png_check_sig(sig, n) (png_sig_cmp((sig), 0, (n)) == 0) /* DEPRECATED */
919
920/* Allocate and initialize png_ptr struct for reading, and any other memory. */
921PNG_EXPORTA(4, png_structp, png_create_read_struct,
922 (png_const_charp user_png_ver, png_voidp error_ptr,
923 png_error_ptr error_fn, png_error_ptr warn_fn),
924 PNG_ALLOCATED);
925
926/* Allocate and initialize png_ptr struct for writing, and any other memory */
927PNG_EXPORTA(5, png_structp, png_create_write_struct,
928 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
929 png_error_ptr warn_fn),
930 PNG_ALLOCATED);
931
932PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
933 (png_const_structrp png_ptr));
934
935PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
936 size_t size));
937
938/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
939 * match up.
940 */
941#ifdef PNG_SETJMP_SUPPORTED
942/* This function returns the jmp_buf built in to *png_ptr. It must be
943 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
944 * unless the default error function is overridden in which case NULL is
945 * acceptable. The size of the jmp_buf is checked against the actual size
946 * allocated by the library - the call will return NULL on a mismatch
947 * indicating an ABI mismatch.
948 */
949PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
950 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
951# define png_jmpbuf(png_ptr) \
952 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
953#else
954# define png_jmpbuf(png_ptr) \
955 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
956#endif
957/* This function should be used by libpng applications in place of
958 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
959 * will use it; otherwise it will call PNG_ABORT(). This function was
960 * added in libpng-1.5.0.
961 */
962PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
963 PNG_NORETURN);
964
965#ifdef PNG_READ_SUPPORTED
966/* Reset the compression stream */
967PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
968#endif
969
970/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
971#ifdef PNG_USER_MEM_SUPPORTED
972PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
973 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
974 png_error_ptr warn_fn,
975 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
976 PNG_ALLOCATED);
977PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
978 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
979 png_error_ptr warn_fn,
980 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
981 PNG_ALLOCATED);
982#endif
983
984/* Write the PNG file signature. */
985PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
986
987/* Write a PNG chunk - size, type, (optional) data, CRC. */
988PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
989 chunk_name, png_const_bytep data, size_t length));
990
991/* Write the start of a PNG chunk - length and chunk name. */
992PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
993 png_const_bytep chunk_name, png_uint_32 length));
994
995/* Write the data of a PNG chunk started with png_write_chunk_start(). */
996PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
997 png_const_bytep data, size_t length));
998
999/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1000PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1001
1002/* Allocate and initialize the info structure */
1003PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1004 PNG_ALLOCATED);
1005
1006/* DEPRECATED: this function allowed init structures to be created using the
1007 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1008 * the API will be removed in the future.
1009 */
1010PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1011 size_t png_info_struct_size), PNG_DEPRECATED);
1012
1013/* Writes all the PNG information before the image. */
1014PNG_EXPORT(20, void, png_write_info_before_PLTE,
1015 (png_structrp png_ptr, png_const_inforp info_ptr));
1016PNG_EXPORT(21, void, png_write_info,
1017 (png_structrp png_ptr, png_const_inforp info_ptr));
1018
1019#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1020/* Read the information before the actual image data. */
1021PNG_EXPORT(22, void, png_read_info,
1022 (png_structrp png_ptr, png_inforp info_ptr));
1023#endif
1024
1025#ifdef PNG_TIME_RFC1123_SUPPORTED
1026 /* Convert to a US string format: there is no localization support in this
1027 * routine. The original implementation used a 29 character buffer in
1028 * png_struct, this will be removed in future versions.
1029 */
1030#if PNG_LIBPNG_VER < 10700
1031/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1032PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1033 png_const_timep ptime),PNG_DEPRECATED);
1034#endif
1035PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1036 png_const_timep ptime));
1037#endif
1038
1039#ifdef PNG_CONVERT_tIME_SUPPORTED
1040/* Convert from a struct tm to png_time */
1041PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1042 const struct tm * ttime));
1043
1044/* Convert from time_t to png_time. Uses gmtime() */
1045PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1046#endif /* CONVERT_tIME */
1047
1048#ifdef PNG_READ_EXPAND_SUPPORTED
1049/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1050PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1051PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1052PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1053PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1054#endif
1055
1056#ifdef PNG_READ_EXPAND_16_SUPPORTED
1057/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1058 * of a tRNS chunk if present.
1059 */
1060PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1061#endif
1062
1063#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1064/* Use blue, green, red order for pixels. */
1065PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1066#endif
1067
1068#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1069/* Expand the grayscale to 24-bit RGB if necessary. */
1070PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1071#endif
1072
1073#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1074/* Reduce RGB to grayscale. */
1075#define PNG_ERROR_ACTION_NONE 1
1076#define PNG_ERROR_ACTION_WARN 2
1077#define PNG_ERROR_ACTION_ERROR 3
1078#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1079
1080PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1081 int error_action, double red, double green))
1082PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1083 int error_action, png_fixed_point red, png_fixed_point green))
1084
1085PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1086 png_ptr));
1087#endif
1088
1089#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1090PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1091 png_colorp palette));
1092#endif
1093
1094#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1095/* How the alpha channel is interpreted - this affects how the color channels
1096 * of a PNG file are returned to the calling application when an alpha channel,
1097 * or a tRNS chunk in a palette file, is present.
1098 *
1099 * This has no effect on the way pixels are written into a PNG output
1100 * datastream. The color samples in a PNG datastream are never premultiplied
1101 * with the alpha samples.
1102 *
1103 * The default is to return data according to the PNG specification: the alpha
1104 * channel is a linear measure of the contribution of the pixel to the
1105 * corresponding composited pixel, and the color channels are unassociated
1106 * (not premultiplied). The gamma encoded color channels must be scaled
1107 * according to the contribution and to do this it is necessary to undo
1108 * the encoding, scale the color values, perform the composition and re-encode
1109 * the values. This is the 'PNG' mode.
1110 *
1111 * The alternative is to 'associate' the alpha with the color information by
1112 * storing color channel values that have been scaled by the alpha.
1113 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1114 * (the latter being the two common names for associated alpha color channels).
1115 *
1116 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1117 * value is equal to the maximum value.
1118 *
1119 * The final choice is to gamma encode the alpha channel as well. This is
1120 * broken because, in practice, no implementation that uses this choice
1121 * correctly undoes the encoding before handling alpha composition. Use this
1122 * choice only if other serious errors in the software or hardware you use
1123 * mandate it; the typical serious error is for dark halos to appear around
1124 * opaque areas of the composited PNG image because of arithmetic overflow.
1125 *
1126 * The API function png_set_alpha_mode specifies which of these choices to use
1127 * with an enumerated 'mode' value and the gamma of the required output:
1128 */
1129#define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1130#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1131#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1132#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1133#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1134#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1135
1136PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1137 double output_gamma))
1138PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1139 int mode, png_fixed_point output_gamma))
1140#endif
1141
1142#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1143/* The output_gamma value is a screen gamma in libpng terminology: it expresses
1144 * how to decode the output values, not how they are encoded.
1145 */
1146#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1147#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1148#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1149#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1150#endif
1151
1152/* The following are examples of calls to png_set_alpha_mode to achieve the
1153 * required overall gamma correction and, where necessary, alpha
1154 * premultiplication.
1155 *
1156 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1157 * This is the default libpng handling of the alpha channel - it is not
1158 * pre-multiplied into the color components. In addition the call states
1159 * that the output is for a sRGB system and causes all PNG files without gAMA
1160 * chunks to be assumed to be encoded using sRGB.
1161 *
1162 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1163 * In this case the output is assumed to be something like an sRGB conformant
1164 * display preceded by a power-law lookup table of power 1.45. This is how
1165 * early Mac systems behaved.
1166 *
1167 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1168 * This is the classic Jim Blinn approach and will work in academic
1169 * environments where everything is done by the book. It has the shortcoming
1170 * of assuming that input PNG data with no gamma information is linear - this
1171 * is unlikely to be correct unless the PNG files where generated locally.
1172 * Most of the time the output precision will be so low as to show
1173 * significant banding in dark areas of the image.
1174 *
1175 * png_set_expand_16(pp);
1176 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1177 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1178 * are assumed to have the sRGB encoding if not marked with a gamma value and
1179 * the output is always 16 bits per component. This permits accurate scaling
1180 * and processing of the data. If you know that your input PNG files were
1181 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1182 * correct value for your system.
1183 *
1184 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1185 * If you just need to composite the PNG image onto an existing background
1186 * and if you control the code that does this you can use the optimization
1187 * setting. In this case you just copy completely opaque pixels to the
1188 * output. For pixels that are not completely transparent (you just skip
1189 * those) you do the composition math using png_composite or png_composite_16
1190 * below then encode the resultant 8-bit or 16-bit values to match the output
1191 * encoding.
1192 *
1193 * Other cases
1194 * If neither the PNG nor the standard linear encoding work for you because
1195 * of the software or hardware you use then you have a big problem. The PNG
1196 * case will probably result in halos around the image. The linear encoding
1197 * will probably result in a washed out, too bright, image (it's actually too
1198 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1199 * substantially reduce the halos. Alternatively try:
1200 *
1201 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1202 * This option will also reduce the halos, but there will be slight dark
1203 * halos round the opaque parts of the image where the background is light.
1204 * In the OPTIMIZED mode the halos will be light halos where the background
1205 * is dark. Take your pick - the halos are unavoidable unless you can get
1206 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1207 * faster.)
1208 *
1209 * When the default gamma of PNG files doesn't match the output gamma.
1210 * If you have PNG files with no gamma information png_set_alpha_mode allows
1211 * you to provide a default gamma, but it also sets the output gamma to the
1212 * matching value. If you know your PNG files have a gamma that doesn't
1213 * match the output you can take advantage of the fact that
1214 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1215 * default if it is not already set:
1216 *
1217 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1218 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1219 * The first call sets both the default and the output gamma values, the
1220 * second call overrides the output gamma without changing the default. This
1221 * is easier than achieving the same effect with png_set_gamma. You must use
1222 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1223 * fire if more than one call to png_set_alpha_mode and png_set_background is
1224 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1225 * are ignored.
1226 */
1227
1228#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1229PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1230#endif
1231
1232#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1233 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1234PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1235#endif
1236
1237#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1238 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1239PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1240#endif
1241
1242#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1243/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1244PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1245 int flags));
1246/* The values of the PNG_FILLER_ defines should NOT be changed */
1247# define PNG_FILLER_BEFORE 0
1248# define PNG_FILLER_AFTER 1
1249/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1250PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1251 png_uint_32 filler, int flags));
1252#endif /* READ_FILLER || WRITE_FILLER */
1253
1254#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1255/* Swap bytes in 16-bit depth files. */
1256PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1257#endif
1258
1259#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1260/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1261PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1262#endif
1263
1264#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1265 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1266/* Swap packing order of pixels in bytes. */
1267PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1268#endif
1269
1270#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1271/* Converts files to legal bit depths. */
1272PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1273 true_bits));
1274#endif
1275
1276#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1277 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1278/* Have the code handle the interlacing. Returns the number of passes.
1279 * MUST be called before png_read_update_info or png_start_read_image,
1280 * otherwise it will not have the desired effect. Note that it is still
1281 * necessary to call png_read_row or png_read_rows png_get_image_height
1282 * times for each pass.
1283*/
1284PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1285#endif
1286
1287#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1288/* Invert monochrome files */
1289PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1290#endif
1291
1292#ifdef PNG_READ_BACKGROUND_SUPPORTED
1293/* Handle alpha and tRNS by replacing with a background color. Prior to
1294 * libpng-1.5.4 this API must not be called before the PNG file header has been
1295 * read. Doing so will result in unexpected behavior and possible warnings or
1296 * errors if the PNG file contains a bKGD chunk.
1297 */
1298PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1299 png_const_color_16p background_color, int background_gamma_code,
1300 int need_expand, double background_gamma))
1301PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1302 png_const_color_16p background_color, int background_gamma_code,
1303 int need_expand, png_fixed_point background_gamma))
1304#endif
1305#ifdef PNG_READ_BACKGROUND_SUPPORTED
1306# define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1307# define PNG_BACKGROUND_GAMMA_SCREEN 1
1308# define PNG_BACKGROUND_GAMMA_FILE 2
1309# define PNG_BACKGROUND_GAMMA_UNIQUE 3
1310#endif
1311
1312#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1313/* Scale a 16-bit depth file down to 8-bit, accurately. */
1314PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1315#endif
1316
1317#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1318#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
1319/* Strip the second byte of information from a 16-bit depth file. */
1320PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1321#endif
1322
1323#ifdef PNG_READ_QUANTIZE_SUPPORTED
1324/* Turn on quantizing, and reduce the palette to the number of colors
1325 * available.
1326 */
1327PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1328 png_colorp palette, int num_palette, int maximum_colors,
1329 png_const_uint_16p histogram, int full_quantize));
1330#endif
1331
1332#ifdef PNG_READ_GAMMA_SUPPORTED
1333/* The threshold on gamma processing is configurable but hard-wired into the
1334 * library. The following is the floating point variant.
1335 */
1336#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1337
1338/* Handle gamma correction. Screen_gamma=(display_exponent).
1339 * NOTE: this API simply sets the screen and file gamma values. It will
1340 * therefore override the value for gamma in a PNG file if it is called after
1341 * the file header has been read - use with care - call before reading the PNG
1342 * file for best results!
1343 *
1344 * These routines accept the same gamma values as png_set_alpha_mode (described
1345 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1346 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1347 * is the inverse of a 'screen gamma' value.
1348 */
1349PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1350 double screen_gamma, double override_file_gamma))
1351PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1352 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1353#endif
1354
1355#ifdef PNG_WRITE_FLUSH_SUPPORTED
1356/* Set how many lines between output flushes - 0 for no flushing */
1357PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1358/* Flush the current PNG output buffer */
1359PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1360#endif
1361
1362/* Optional update palette with requested transformations */
1363PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1364
1365/* Optional call to update the users info structure */
1366PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1367 png_inforp info_ptr));
1368
1369#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1370/* Read one or more rows of image data. */
1371PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1372 png_bytepp display_row, png_uint_32 num_rows));
1373#endif
1374
1375#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1376/* Read a row of data. */
1377PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1378 png_bytep display_row));
1379#endif
1380
1381#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1382/* Read the whole image into memory at once. */
1383PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1384#endif
1385
1386/* Write a row of image data */
1387PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1388 png_const_bytep row));
1389
1390/* Write a few rows of image data: (*row) is not written; however, the type
1391 * is declared as writeable to maintain compatibility with previous versions
1392 * of libpng and to allow the 'display_row' array from read_rows to be passed
1393 * unchanged to write_rows.
1394 */
1395PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1396 png_uint_32 num_rows));
1397
1398/* Write the image data */
1399PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1400
1401/* Write the end of the PNG file. */
1402PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1403 png_inforp info_ptr));
1404
1405#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1406/* Read the end of the PNG file. */
1407PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1408#endif
1409
1410/* Free any memory associated with the png_info_struct */
1411PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1412 png_infopp info_ptr_ptr));
1413
1414/* Free any memory associated with the png_struct and the png_info_structs */
1415PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1416 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1417
1418/* Free any memory associated with the png_struct and the png_info_structs */
1419PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1420 png_infopp info_ptr_ptr));
1421
1422/* Set the libpng method of handling chunk CRC errors */
1423PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1424 int ancil_action));
1425
1426/* Values for png_set_crc_action() say how to handle CRC errors in
1427 * ancillary and critical chunks, and whether to use the data contained
1428 * therein. Note that it is impossible to "discard" data in a critical
1429 * chunk. For versions prior to 0.90, the action was always error/quit,
1430 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1431 * chunks is warn/discard. These values should NOT be changed.
1432 *
1433 * value action:critical action:ancillary
1434 */
1435#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1436#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1437#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1438#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1439#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1440#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1441
1442#ifdef PNG_WRITE_SUPPORTED
1443/* These functions give the user control over the scan-line filtering in
1444 * libpng and the compression methods used by zlib. These functions are
1445 * mainly useful for testing, as the defaults should work with most users.
1446 * Those users who are tight on memory or want faster performance at the
1447 * expense of compression can modify them. See the compression library
1448 * header file (zlib.h) for an explanation of the compression functions.
1449 */
1450
1451/* Set the filtering method(s) used by libpng. Currently, the only valid
1452 * value for "method" is 0.
1453 */
1454PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1455 int filters));
1456#endif /* WRITE */
1457
1458/* Flags for png_set_filter() to say which filters to use. The flags
1459 * are chosen so that they don't conflict with real filter types
1460 * below, in case they are supplied instead of the #defined constants.
1461 * These values should NOT be changed.
1462 */
1463#define PNG_NO_FILTERS 0x00
1464#define PNG_FILTER_NONE 0x08
1465#define PNG_FILTER_SUB 0x10
1466#define PNG_FILTER_UP 0x20
1467#define PNG_FILTER_AVG 0x40
1468#define PNG_FILTER_PAETH 0x80
1469#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
1470#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
1471
1472/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1473 * These defines should NOT be changed.
1474 */
1475#define PNG_FILTER_VALUE_NONE 0
1476#define PNG_FILTER_VALUE_SUB 1
1477#define PNG_FILTER_VALUE_UP 2
1478#define PNG_FILTER_VALUE_AVG 3
1479#define PNG_FILTER_VALUE_PAETH 4
1480#define PNG_FILTER_VALUE_LAST 5
1481
1482#ifdef PNG_WRITE_SUPPORTED
1483#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1484PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1485 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1486 png_const_doublep filter_costs))
1487PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1488 (png_structrp png_ptr, int heuristic_method, int num_weights,
1489 png_const_fixed_point_p filter_weights,
1490 png_const_fixed_point_p filter_costs))
1491#endif /* WRITE_WEIGHTED_FILTER */
1492
1493/* The following are no longer used and will be removed from libpng-1.7: */
1494#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1495#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1496#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1497#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1498
1499/* Set the library compression level. Currently, valid values range from
1500 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1501 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1502 * shown that zlib compression levels 3-6 usually perform as well as level 9
1503 * for PNG images, and do considerably fewer calculations. In the future,
1504 * these values may not correspond directly to the zlib compression levels.
1505 */
1506#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1507PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1508 int level));
1509
1510PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1511 int mem_level));
1512
1513PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1514 int strategy));
1515
1516/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1517 * smaller value of window_bits if it can do so safely.
1518 */
1519PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1520 int window_bits));
1521
1522PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1523 int method));
1524#endif /* WRITE_CUSTOMIZE_COMPRESSION */
1525
1526#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1527/* Also set zlib parameters for compressing non-IDAT chunks */
1528PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1529 int level));
1530
1531PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1532 int mem_level));
1533
1534PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1535 int strategy));
1536
1537/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1538 * smaller value of window_bits if it can do so safely.
1539 */
1540PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1541 (png_structrp png_ptr, int window_bits));
1542
1543PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1544 int method));
1545#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1546#endif /* WRITE */
1547
1548/* These next functions are called for input/output, memory, and error
1549 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1550 * and call standard C I/O routines such as fread(), fwrite(), and
1551 * fprintf(). These functions can be made to use other I/O routines
1552 * at run time for those applications that need to handle I/O in a
1553 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1554 * more information.
1555 */
1556
1557#ifdef PNG_STDIO_SUPPORTED
1558/* Initialize the input/output for the PNG file to the default functions. */
1559PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1560#endif
1561
1562/* Replace the (error and abort), and warning functions with user
1563 * supplied functions. If no messages are to be printed you must still
1564 * write and use replacement functions. The replacement error_fn should
1565 * still do a longjmp to the last setjmp location if you are using this
1566 * method of error handling. If error_fn or warning_fn is NULL, the
1567 * default function will be used.
1568 */
1569
1570PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1571 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1572
1573/* Return the user pointer associated with the error functions */
1574PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1575
1576/* Replace the default data output functions with a user supplied one(s).
1577 * If buffered output is not used, then output_flush_fn can be set to NULL.
1578 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1579 * output_flush_fn will be ignored (and thus can be NULL).
1580 * It is probably a mistake to use NULL for output_flush_fn if
1581 * write_data_fn is not also NULL unless you have built libpng with
1582 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1583 * default flush function, which uses the standard *FILE structure, will
1584 * be used.
1585 */
1586PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1587 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1588
1589/* Replace the default data input function with a user supplied one. */
1590PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1591 png_rw_ptr read_data_fn));
1592
1593/* Return the user pointer associated with the I/O functions */
1594PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1595
1596PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1597 png_read_status_ptr read_row_fn));
1598
1599PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1600 png_write_status_ptr write_row_fn));
1601
1602#ifdef PNG_USER_MEM_SUPPORTED
1603/* Replace the default memory allocation functions with user supplied one(s). */
1604PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1605 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1606/* Return the user pointer associated with the memory functions */
1607PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1608#endif
1609
1610#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1611PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1612 png_user_transform_ptr read_user_transform_fn));
1613#endif
1614
1615#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1616PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1617 png_user_transform_ptr write_user_transform_fn));
1618#endif
1619
1620#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1621PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1622 png_voidp user_transform_ptr, int user_transform_depth,
1623 int user_transform_channels));
1624/* Return the user pointer associated with the user transform functions */
1625PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1626 (png_const_structrp png_ptr));
1627#endif
1628
1629#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1630/* Return information about the row currently being processed. Note that these
1631 * APIs do not fail but will return unexpected results if called outside a user
1632 * transform callback. Also note that when transforming an interlaced image the
1633 * row number is the row number within the sub-image of the interlace pass, so
1634 * the value will increase to the height of the sub-image (not the full image)
1635 * then reset to 0 for the next pass.
1636 *
1637 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1638 * find the output pixel (x,y) given an interlaced sub-image pixel
1639 * (row,col,pass). (See below for these macros.)
1640 */
1641PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1642PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1643#endif
1644
1645#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1646/* This callback is called only for *unknown* chunks. If
1647 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1648 * chunks to be treated as unknown, however in this case the callback must do
1649 * any processing required by the chunk (e.g. by calling the appropriate
1650 * png_set_ APIs.)
1651 *
1652 * There is no write support - on write, by default, all the chunks in the
1653 * 'unknown' list are written in the specified position.
1654 *
1655 * The integer return from the callback function is interpreted thus:
1656 *
1657 * negative: An error occurred; png_chunk_error will be called.
1658 * zero: The chunk was not handled, the chunk will be saved. A critical
1659 * chunk will cause an error at this point unless it is to be saved.
1660 * positive: The chunk was handled, libpng will ignore/discard it.
1661 *
1662 * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about
1663 * how this behavior will change in libpng 1.7
1664 */
1665PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1666 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1667#endif
1668
1669#ifdef PNG_USER_CHUNKS_SUPPORTED
1670PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1671#endif
1672
1673#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1674/* Sets the function callbacks for the push reader, and a pointer to a
1675 * user-defined structure available to the callback functions.
1676 */
1677PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1678 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1679 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1680
1681/* Returns the user pointer associated with the push read functions */
1682PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1683 (png_const_structrp png_ptr));
1684
1685/* Function to be called when data becomes available */
1686PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1687 png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
1688
1689/* A function which may be called *only* within png_process_data to stop the
1690 * processing of any more data. The function returns the number of bytes
1691 * remaining, excluding any that libpng has cached internally. A subsequent
1692 * call to png_process_data must supply these bytes again. If the argument
1693 * 'save' is set to true the routine will first save all the pending data and
1694 * will always return 0.
1695 */
1696PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
1697
1698/* A function which may be called *only* outside (after) a call to
1699 * png_process_data. It returns the number of bytes of data to skip in the
1700 * input. Normally it will return 0, but if it returns a non-zero value the
1701 * application must skip than number of bytes of input data and pass the
1702 * following data to the next call to png_process_data.
1703 */
1704PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1705
1706/* Function that combines rows. 'new_row' is a flag that should come from
1707 * the callback and be non-NULL if anything needs to be done; the library
1708 * stores its own version of the new data internally and ignores the passed
1709 * in value.
1710 */
1711PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1712 png_bytep old_row, png_const_bytep new_row));
1713#endif /* PROGRESSIVE_READ */
1714
1715PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1716 png_alloc_size_t size), PNG_ALLOCATED);
1717/* Added at libpng version 1.4.0 */
1718PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1719 png_alloc_size_t size), PNG_ALLOCATED);
1720
1721/* Added at libpng version 1.2.4 */
1722PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1723 png_alloc_size_t size), PNG_ALLOCATED);
1724
1725/* Frees a pointer allocated by png_malloc() */
1726PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1727
1728/* Free data that was allocated internally */
1729PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1730 png_inforp info_ptr, png_uint_32 free_me, int num));
1731
1732/* Reassign the responsibility for freeing existing data, whether allocated
1733 * by libpng or by the application; this works on the png_info structure passed
1734 * in, without changing the state for other png_info structures.
1735 */
1736PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1737 png_inforp info_ptr, int freer, png_uint_32 mask));
1738
1739/* Assignments for png_data_freer */
1740#define PNG_DESTROY_WILL_FREE_DATA 1
1741#define PNG_SET_WILL_FREE_DATA 1
1742#define PNG_USER_WILL_FREE_DATA 2
1743/* Flags for png_ptr->free_me and info_ptr->free_me */
1744#define PNG_FREE_HIST 0x0008U
1745#define PNG_FREE_ICCP 0x0010U
1746#define PNG_FREE_SPLT 0x0020U
1747#define PNG_FREE_ROWS 0x0040U
1748#define PNG_FREE_PCAL 0x0080U
1749#define PNG_FREE_SCAL 0x0100U
1750#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1751# define PNG_FREE_UNKN 0x0200U
1752#endif
1753/* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */
1754#define PNG_FREE_PLTE 0x1000U
1755#define PNG_FREE_TRNS 0x2000U
1756#define PNG_FREE_TEXT 0x4000U
1757#define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
1758#define PNG_FREE_ALL 0xffffU
1759#define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1760
1761#ifdef PNG_USER_MEM_SUPPORTED
1762PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1763 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1764PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1765 png_voidp ptr), PNG_DEPRECATED);
1766#endif
1767
1768#ifdef PNG_ERROR_TEXT_SUPPORTED
1769/* Fatal error in PNG image of libpng - can't continue */
1770PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1771 png_const_charp error_message), PNG_NORETURN);
1772
1773/* The same, but the chunk name is prepended to the error string. */
1774PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1775 png_const_charp error_message), PNG_NORETURN);
1776
1777#else
1778/* Fatal error in PNG image of libpng - can't continue */
1779PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1780# define png_error(s1,s2) png_err(s1)
1781# define png_chunk_error(s1,s2) png_err(s1)
1782#endif
1783
1784#ifdef PNG_WARNINGS_SUPPORTED
1785/* Non-fatal error in libpng. Can continue, but may have a problem. */
1786PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1787 png_const_charp warning_message));
1788
1789/* Non-fatal error in libpng, chunk name is prepended to message. */
1790PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1791 png_const_charp warning_message));
1792#else
1793# define png_warning(s1,s2) ((void)(s1))
1794# define png_chunk_warning(s1,s2) ((void)(s1))
1795#endif
1796
1797#ifdef PNG_BENIGN_ERRORS_SUPPORTED
1798/* Benign error in libpng. Can continue, but may have a problem.
1799 * User can choose whether to handle as a fatal error or as a warning. */
1800PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1801 png_const_charp warning_message));
1802
1803#ifdef PNG_READ_SUPPORTED
1804/* Same, chunk name is prepended to message (only during read) */
1805PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1806 png_const_charp warning_message));
1807#endif
1808
1809PNG_EXPORT(109, void, png_set_benign_errors,
1810 (png_structrp png_ptr, int allowed));
1811#else
1812# ifdef PNG_ALLOW_BENIGN_ERRORS
1813# define png_benign_error png_warning
1814# define png_chunk_benign_error png_chunk_warning
1815# else
1816# define png_benign_error png_error
1817# define png_chunk_benign_error png_chunk_error
1818# endif
1819#endif
1820
1821/* The png_set_<chunk> functions are for storing values in the png_info_struct.
1822 * Similarly, the png_get_<chunk> calls are used to read values from the
1823 * png_info_struct, either storing the parameters in the passed variables, or
1824 * setting pointers into the png_info_struct where the data is stored. The
1825 * png_get_<chunk> functions return a non-zero value if the data was available
1826 * in info_ptr, or return zero and do not change any of the parameters if the
1827 * data was not available.
1828 *
1829 * These functions should be used instead of directly accessing png_info
1830 * to avoid problems with future changes in the size and internal layout of
1831 * png_info_struct.
1832 */
1833/* Returns "flag" if chunk data is valid in info_ptr. */
1834PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1835 png_const_inforp info_ptr, png_uint_32 flag));
1836
1837/* Returns number of bytes needed to hold a transformed row. */
1838PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1839 png_const_inforp info_ptr));
1840
1841#ifdef PNG_INFO_IMAGE_SUPPORTED
1842/* Returns row_pointers, which is an array of pointers to scanlines that was
1843 * returned from png_read_png().
1844 */
1845PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
1846 png_const_inforp info_ptr));
1847
1848/* Set row_pointers, which is an array of pointers to scanlines for use
1849 * by png_write_png().
1850 */
1851PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
1852 png_inforp info_ptr, png_bytepp row_pointers));
1853#endif
1854
1855/* Returns number of color channels in image. */
1856PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
1857 png_const_inforp info_ptr));
1858
1859#ifdef PNG_EASY_ACCESS_SUPPORTED
1860/* Returns image width in pixels. */
1861PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
1862 png_const_inforp info_ptr));
1863
1864/* Returns image height in pixels. */
1865PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
1866 png_const_inforp info_ptr));
1867
1868/* Returns image bit_depth. */
1869PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
1870 png_const_inforp info_ptr));
1871
1872/* Returns image color_type. */
1873PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
1874 png_const_inforp info_ptr));
1875
1876/* Returns image filter_type. */
1877PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
1878 png_const_inforp info_ptr));
1879
1880/* Returns image interlace_type. */
1881PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
1882 png_const_inforp info_ptr));
1883
1884/* Returns image compression_type. */
1885PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
1886 png_const_inforp info_ptr));
1887
1888/* Returns image resolution in pixels per meter, from pHYs chunk data. */
1889PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
1890 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1891PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
1892 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1893PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
1894 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1895
1896/* Returns pixel aspect ratio, computed from pHYs chunk data. */
1897PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
1898 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1899PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
1900 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1901
1902/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1903PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
1904 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1905PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
1906 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1907PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
1908 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1909PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
1910 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1911
1912#endif /* EASY_ACCESS */
1913
1914#ifdef PNG_READ_SUPPORTED
1915/* Returns pointer to signature string read from PNG header */
1916PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
1917 png_const_inforp info_ptr));
1918#endif
1919
1920#ifdef PNG_bKGD_SUPPORTED
1921PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
1922 png_inforp info_ptr, png_color_16p *background));
1923#endif
1924
1925#ifdef PNG_bKGD_SUPPORTED
1926PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
1927 png_inforp info_ptr, png_const_color_16p background));
1928#endif
1929
1930#ifdef PNG_cHRM_SUPPORTED
1931PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
1932 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
1933 double *red_y, double *green_x, double *green_y, double *blue_x,
1934 double *blue_y))
1935PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
1936 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
1937 double *green_X, double *green_Y, double *green_Z, double *blue_X,
1938 double *blue_Y, double *blue_Z))
1939PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
1940 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1941 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
1942 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
1943 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
1944 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
1945PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
1946 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1947 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
1948 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
1949 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
1950 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
1951 png_fixed_point *int_blue_Z))
1952#endif
1953
1954#ifdef PNG_cHRM_SUPPORTED
1955PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
1956 png_inforp info_ptr,
1957 double white_x, double white_y, double red_x, double red_y, double green_x,
1958 double green_y, double blue_x, double blue_y))
1959PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
1960 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
1961 double green_X, double green_Y, double green_Z, double blue_X,
1962 double blue_Y, double blue_Z))
1963PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
1964 png_inforp info_ptr, png_fixed_point int_white_x,
1965 png_fixed_point int_white_y, png_fixed_point int_red_x,
1966 png_fixed_point int_red_y, png_fixed_point int_green_x,
1967 png_fixed_point int_green_y, png_fixed_point int_blue_x,
1968 png_fixed_point int_blue_y))
1969PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
1970 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
1971 png_fixed_point int_red_Z, png_fixed_point int_green_X,
1972 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
1973 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
1974 png_fixed_point int_blue_Z))
1975#endif
1976
1977#ifdef PNG_eXIf_SUPPORTED
1978PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
1979 png_inforp info_ptr, png_bytep *exif));
1980PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr,
1981 png_inforp info_ptr, png_bytep exif));
1982
1983PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr,
1984 png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif));
1985PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr,
1986 png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif));
1987#endif
1988
1989#ifdef PNG_gAMA_SUPPORTED
1990PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
1991 png_const_inforp info_ptr, double *file_gamma))
1992PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
1993 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1994 png_fixed_point *int_file_gamma))
1995#endif
1996
1997#ifdef PNG_gAMA_SUPPORTED
1998PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
1999 png_inforp info_ptr, double file_gamma))
2000PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2001 png_inforp info_ptr, png_fixed_point int_file_gamma))
2002#endif
2003
2004#ifdef PNG_hIST_SUPPORTED
2005PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2006 png_inforp info_ptr, png_uint_16p *hist));
2007PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2008 png_inforp info_ptr, png_const_uint_16p hist));
2009#endif
2010
2011PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2012 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2013 int *bit_depth, int *color_type, int *interlace_method,
2014 int *compression_method, int *filter_method));
2015
2016PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2017 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2018 int color_type, int interlace_method, int compression_method,
2019 int filter_method));
2020
2021#ifdef PNG_oFFs_SUPPORTED
2022PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2023 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2024 int *unit_type));
2025#endif
2026
2027#ifdef PNG_oFFs_SUPPORTED
2028PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2029 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2030 int unit_type));
2031#endif
2032
2033#ifdef PNG_pCAL_SUPPORTED
2034PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2035 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2036 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2037 png_charpp *params));
2038#endif
2039
2040#ifdef PNG_pCAL_SUPPORTED
2041PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2042 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2043 int type, int nparams, png_const_charp units, png_charpp params));
2044#endif
2045
2046#ifdef PNG_pHYs_SUPPORTED
2047PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2048 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2049 int *unit_type));
2050#endif
2051
2052#ifdef PNG_pHYs_SUPPORTED
2053PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2054 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2055#endif
2056
2057PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2058 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2059
2060PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2061 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2062
2063#ifdef PNG_sBIT_SUPPORTED
2064PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2065 png_inforp info_ptr, png_color_8p *sig_bit));
2066#endif
2067
2068#ifdef PNG_sBIT_SUPPORTED
2069PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2070 png_inforp info_ptr, png_const_color_8p sig_bit));
2071#endif
2072
2073#ifdef PNG_sRGB_SUPPORTED
2074PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2075 png_const_inforp info_ptr, int *file_srgb_intent));
2076#endif
2077
2078#ifdef PNG_sRGB_SUPPORTED
2079PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2080 png_inforp info_ptr, int srgb_intent));
2081PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2082 png_inforp info_ptr, int srgb_intent));
2083#endif
2084
2085#ifdef PNG_iCCP_SUPPORTED
2086PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2087 png_inforp info_ptr, png_charpp name, int *compression_type,
2088 png_bytepp profile, png_uint_32 *proflen));
2089#endif
2090
2091#ifdef PNG_iCCP_SUPPORTED
2092PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2093 png_inforp info_ptr, png_const_charp name, int compression_type,
2094 png_const_bytep profile, png_uint_32 proflen));
2095#endif
2096
2097#ifdef PNG_sPLT_SUPPORTED
2098PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2099 png_inforp info_ptr, png_sPLT_tpp entries));
2100#endif
2101
2102#ifdef PNG_sPLT_SUPPORTED
2103PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2104 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2105#endif
2106
2107#ifdef PNG_TEXT_SUPPORTED
2108/* png_get_text also returns the number of text chunks in *num_text */
2109PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2110 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2111#endif
2112
2113/* Note while png_set_text() will accept a structure whose text,
2114 * language, and translated keywords are NULL pointers, the structure
2115 * returned by png_get_text will always contain regular
2116 * zero-terminated C strings. They might be empty strings but
2117 * they will never be NULL pointers.
2118 */
2119
2120#ifdef PNG_TEXT_SUPPORTED
2121PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2122 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2123#endif
2124
2125#ifdef PNG_tIME_SUPPORTED
2126PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2127 png_inforp info_ptr, png_timep *mod_time));
2128#endif
2129
2130#ifdef PNG_tIME_SUPPORTED
2131PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2132 png_inforp info_ptr, png_const_timep mod_time));
2133#endif
2134
2135#ifdef PNG_tRNS_SUPPORTED
2136PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2137 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2138 png_color_16p *trans_color));
2139#endif
2140
2141#ifdef PNG_tRNS_SUPPORTED
2142PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2143 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2144 png_const_color_16p trans_color));
2145#endif
2146
2147#ifdef PNG_sCAL_SUPPORTED
2148PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2149 png_const_inforp info_ptr, int *unit, double *width, double *height))
2150#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2151 defined(PNG_FLOATING_POINT_SUPPORTED)
2152/* NOTE: this API is currently implemented using floating point arithmetic,
2153 * consequently it can only be used on systems with floating point support.
2154 * In any case the range of values supported by png_fixed_point is small and it
2155 * is highly recommended that png_get_sCAL_s be used instead.
2156 */
2157PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2158 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2159 png_fixed_point *width, png_fixed_point *height))
2160#endif
2161PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2162 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2163 png_charpp swidth, png_charpp sheight));
2164
2165PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2166 png_inforp info_ptr, int unit, double width, double height))
2167PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2168 png_inforp info_ptr, int unit, png_fixed_point width,
2169 png_fixed_point height))
2170PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2171 png_inforp info_ptr, int unit,
2172 png_const_charp swidth, png_const_charp sheight));
2173#endif /* sCAL */
2174
2175#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2176/* Provide the default handling for all unknown chunks or, optionally, for
2177 * specific unknown chunks.
2178 *
2179 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2180 * ignored and the default was used, the per-chunk setting only had an effect on
2181 * write. If you wish to have chunk-specific handling on read in code that must
2182 * work on earlier versions you must use a user chunk callback to specify the
2183 * desired handling (keep or discard.)
2184 *
2185 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2186 * parameter is interpreted as follows:
2187 *
2188 * READ:
2189 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2190 * Known chunks: do normal libpng processing, do not keep the chunk (but
2191 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2192 * Unknown chunks: for a specific chunk use the global default, when used
2193 * as the default discard the chunk data.
2194 * PNG_HANDLE_CHUNK_NEVER:
2195 * Discard the chunk data.
2196 * PNG_HANDLE_CHUNK_IF_SAFE:
2197 * Keep the chunk data if the chunk is not critical else raise a chunk
2198 * error.
2199 * PNG_HANDLE_CHUNK_ALWAYS:
2200 * Keep the chunk data.
2201 *
2202 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2203 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2204 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2205 * it simply resets the behavior to the libpng default.
2206 *
2207 * INTERACTION WITH USER CHUNK CALLBACKS:
2208 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2209 * callback and the callback returns 0; the chunk is then always stored *unless*
2210 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2211 * the global default is *not* used in this case. (In effect the per-chunk
2212 * value is incremented to at least IF_SAFE.)
2213 *
2214 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2215 * per-chunk defaults will be honored. If you want to preserve the current
2216 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2217 * as the default - if you don't do this libpng 1.6 will issue a warning.
2218 *
2219 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2220 * earlier simply return '1' (handled).
2221 *
2222 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2223 * If this is *not* set known chunks will always be handled by libpng and
2224 * will never be stored in the unknown chunk list. Known chunks listed to
2225 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2226 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2227 * by libpng, in addition critical chunks must either be processed by the
2228 * callback or saved.
2229 *
2230 * The IHDR and IEND chunks must not be listed. Because this turns off the
2231 * default handling for chunks that would otherwise be recognized the
2232 * behavior of libpng transformations may well become incorrect!
2233 *
2234 * WRITE:
2235 * When writing chunks the options only apply to the chunks specified by
2236 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2237 * required by png_set_ calls and will always write the core critical chunks
2238 * (as required for PLTE).
2239 *
2240 * Each chunk in the png_set_unknown_chunks list is looked up in the
2241 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2242 * interpreted as follows:
2243 *
2244 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2245 * Write safe-to-copy chunks and write other chunks if the global
2246 * default is set to _ALWAYS, otherwise don't write this chunk.
2247 * PNG_HANDLE_CHUNK_NEVER:
2248 * Do not write the chunk.
2249 * PNG_HANDLE_CHUNK_IF_SAFE:
2250 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2251 * PNG_HANDLE_CHUNK_ALWAYS:
2252 * Write the chunk.
2253 *
2254 * Note that the default behavior is effectively the opposite of the read case -
2255 * in read unknown chunks are not stored by default, in write they are written
2256 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2257 * - on write the safe-to-copy bit is checked, on read the critical bit is
2258 * checked and on read if the chunk is critical an error will be raised.
2259 *
2260 * num_chunks:
2261 * ===========
2262 * If num_chunks is positive, then the "keep" parameter specifies the manner
2263 * for handling only those chunks appearing in the chunk_list array,
2264 * otherwise the chunk list array is ignored.
2265 *
2266 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2267 * unknown chunks, as described above.
2268 *
2269 * If num_chunks is negative, then the "keep" parameter specifies the manner
2270 * for handling all unknown chunks plus all chunks recognized by libpng
2271 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2272 * be processed by libpng.
2273 */
2274#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2275PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2276 int keep, png_const_bytep chunk_list, int num_chunks));
2277#endif /* HANDLE_AS_UNKNOWN */
2278
2279/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2280 * the result is therefore true (non-zero) if special handling is required,
2281 * false for the default handling.
2282 */
2283PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2284 png_const_bytep chunk_name));
2285#endif /* SET_UNKNOWN_CHUNKS */
2286
2287#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2288PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2289 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2290 int num_unknowns));
2291 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2292 * unknowns to the location currently stored in the png_struct. This is
2293 * invariably the wrong value on write. To fix this call the following API
2294 * for each chunk in the list with the correct location. If you know your
2295 * code won't be compiled on earlier versions you can rely on
2296 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2297 * the correct thing.
2298 */
2299
2300PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2301 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2302
2303PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2304 png_inforp info_ptr, png_unknown_chunkpp entries));
2305#endif
2306
2307/* Png_free_data() will turn off the "valid" flag for anything it frees.
2308 * If you need to turn it off for a chunk that your application has freed,
2309 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2310 */
2311PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2312 png_inforp info_ptr, int mask));
2313
2314#ifdef PNG_INFO_IMAGE_SUPPORTED
2315/* The "params" pointer is currently not used and is for future expansion. */
2316#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2317PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2318 int transforms, png_voidp params));
2319#endif
2320#ifdef PNG_WRITE_SUPPORTED
2321PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2322 int transforms, png_voidp params));
2323#endif
2324#endif
2325
2326PNG_EXPORT(180, png_const_charp, png_get_copyright,
2327 (png_const_structrp png_ptr));
2328PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2329 (png_const_structrp png_ptr));
2330PNG_EXPORT(182, png_const_charp, png_get_header_version,
2331 (png_const_structrp png_ptr));
2332PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2333 (png_const_structrp png_ptr));
2334
2335#ifdef PNG_MNG_FEATURES_SUPPORTED
2336PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2337 png_uint_32 mng_features_permitted));
2338#endif
2339
2340/* For use in png_set_keep_unknown, added to version 1.2.6 */
2341#define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2342#define PNG_HANDLE_CHUNK_NEVER 1
2343#define PNG_HANDLE_CHUNK_IF_SAFE 2
2344#define PNG_HANDLE_CHUNK_ALWAYS 3
2345#define PNG_HANDLE_CHUNK_LAST 4
2346
2347/* Strip the prepended error numbers ("#nnn ") from error and warning
2348 * messages before passing them to the error or warning handler.
2349 */
2350#ifdef PNG_ERROR_NUMBERS_SUPPORTED
2351PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2352 png_uint_32 strip_mode));
2353#endif
2354
2355/* Added in libpng-1.2.6 */
2356#ifdef PNG_SET_USER_LIMITS_SUPPORTED
2357PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2358 png_uint_32 user_width_max, png_uint_32 user_height_max));
2359PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2360 (png_const_structrp png_ptr));
2361PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2362 (png_const_structrp png_ptr));
2363/* Added in libpng-1.4.0 */
2364PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2365 png_uint_32 user_chunk_cache_max));
2366PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2367 (png_const_structrp png_ptr));
2368/* Added in libpng-1.4.1 */
2369PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2370 png_alloc_size_t user_chunk_cache_max));
2371PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2372 (png_const_structrp png_ptr));
2373#endif
2374
2375#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2376PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2377 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2378
2379PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2380 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2381
2382PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2383 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2384
2385PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2386 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2387#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2388PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2389 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2390#endif
2391
2392PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2393 png_const_inforp info_ptr))
2394#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2395PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2396 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2397#endif
2398
2399# ifdef PNG_pHYs_SUPPORTED
2400PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2401 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2402 int *unit_type));
2403# endif /* pHYs */
2404#endif /* INCH_CONVERSIONS */
2405
2406/* Added in libpng-1.4.0 */
2407#ifdef PNG_IO_STATE_SUPPORTED
2408PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2409
2410/* Removed from libpng 1.6; use png_get_io_chunk_type. */
2411PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2412 PNG_DEPRECATED)
2413
2414PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2415 (png_const_structrp png_ptr));
2416
2417/* The flags returned by png_get_io_state() are the following: */
2418# define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2419# define PNG_IO_READING 0x0001 /* currently reading */
2420# define PNG_IO_WRITING 0x0002 /* currently writing */
2421# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2422# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2423# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2424# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2425# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2426# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2427#endif /* IO_STATE */
2428
2429/* Interlace support. The following macros are always defined so that if
2430 * libpng interlace handling is turned off the macros may be used to handle
2431 * interlaced images within the application.
2432 */
2433#define PNG_INTERLACE_ADAM7_PASSES 7
2434
2435/* Two macros to return the first row and first column of the original,
2436 * full, image which appears in a given pass. 'pass' is in the range 0
2437 * to 6 and the result is in the range 0 to 7.
2438 */
2439#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2440#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2441
2442/* A macro to return the offset between pixels in the output row for a pair of
2443 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2444 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2445 * COL_OFFSET is from one column to the next, within a row.
2446 */
2447#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2448#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2449
2450/* Two macros to help evaluate the number of rows or columns in each
2451 * pass. This is expressed as a shift - effectively log2 of the number or
2452 * rows or columns in each 8x8 tile of the original image.
2453 */
2454#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2455#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2456
2457/* Hence two macros to determine the number of rows or columns in a given
2458 * pass of an image given its height or width. In fact these macros may
2459 * return non-zero even though the sub-image is empty, because the other
2460 * dimension may be empty for a small image.
2461 */
2462#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2463 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2464#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2465 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2466
2467/* For the reader row callbacks (both progressive and sequential) it is
2468 * necessary to find the row in the output image given a row in an interlaced
2469 * image, so two more macros:
2470 */
2471#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2472 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2473#define PNG_COL_FROM_PASS_COL(x_in, pass) \
2474 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2475
2476/* Two macros which return a boolean (0 or 1) saying whether the given row
2477 * or column is in a particular pass. These use a common utility macro that
2478 * returns a mask for a given pass - the offset 'off' selects the row or
2479 * column version. The mask has the appropriate bit set for each column in
2480 * the tile.
2481 */
2482#define PNG_PASS_MASK(pass,off) ( \
2483 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2484 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2485
2486#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2487 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2488#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2489 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2490
2491#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2492/* With these routines we avoid an integer divide, which will be slower on
2493 * most machines. However, it does take more operations than the corresponding
2494 * divide method, so it may be slower on a few RISC systems. There are two
2495 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2496 *
2497 * Note that the rounding factors are NOT supposed to be the same! 128 and
2498 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2499 * standard method.
2500 *
2501 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2502 */
2503
2504 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2505
2506# define png_composite(composite, fg, alpha, bg) \
2507 { \
2508 png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2509 * (png_uint_16)(alpha) \
2510 + (png_uint_16)(bg)*(png_uint_16)(255 \
2511 - (png_uint_16)(alpha)) + 128); \
2512 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
2513 }
2514
2515# define png_composite_16(composite, fg, alpha, bg) \
2516 { \
2517 png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2518 * (png_uint_32)(alpha) \
2519 + (png_uint_32)(bg)*(65535 \
2520 - (png_uint_32)(alpha)) + 32768); \
2521 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
2522 }
2523
2524#else /* Standard method using integer division */
2525
2526# define png_composite(composite, fg, alpha, bg) \
2527 (composite) = \
2528 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2529 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2530 127) / 255))
2531
2532# define png_composite_16(composite, fg, alpha, bg) \
2533 (composite) = \
2534 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2535 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2536 32767) / 65535))
2537#endif /* READ_COMPOSITE_NODIV */
2538
2539#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2540PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2541PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2542PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2543#endif
2544
2545PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2546 png_const_bytep buf));
2547/* No png_get_int_16 -- may be added if there's a real need for it. */
2548
2549/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2550#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2551PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2552#endif
2553#ifdef PNG_SAVE_INT_32_SUPPORTED
2554PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2555#endif
2556
2557/* Place a 16-bit number into a buffer in PNG byte order.
2558 * The parameter is declared unsigned int, not png_uint_16,
2559 * just to avoid potential problems on pre-ANSI C compilers.
2560 */
2561#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2562PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2563/* No png_save_int_16 -- may be added if there's a real need for it. */
2564#endif
2565
2566#ifdef PNG_USE_READ_MACROS
2567/* Inline macros to do direct reads of bytes from the input buffer.
2568 * The png_get_int_32() routine assumes we are using two's complement
2569 * format for negative values, which is almost certainly true.
2570 */
2571# define PNG_get_uint_32(buf) \
2572 (((png_uint_32)(*(buf)) << 24) + \
2573 ((png_uint_32)(*((buf) + 1)) << 16) + \
2574 ((png_uint_32)(*((buf) + 2)) << 8) + \
2575 ((png_uint_32)(*((buf) + 3))))
2576
2577 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2578 * function) incorrectly returned a value of type png_uint_32.
2579 */
2580# define PNG_get_uint_16(buf) \
2581 ((png_uint_16) \
2582 (((unsigned int)(*(buf)) << 8) + \
2583 ((unsigned int)(*((buf) + 1)))))
2584
2585# define PNG_get_int_32(buf) \
2586 ((png_int_32)((*(buf) & 0x80) \
2587 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2588 : (png_int_32)png_get_uint_32(buf)))
2589
2590/* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2591 * but defining a macro name prefixed with PNG_PREFIX.
2592 */
2593# ifndef PNG_PREFIX
2594# define png_get_uint_32(buf) PNG_get_uint_32(buf)
2595# define png_get_uint_16(buf) PNG_get_uint_16(buf)
2596# define png_get_int_32(buf) PNG_get_int_32(buf)
2597# endif
2598#else
2599# ifdef PNG_PREFIX
2600 /* No macros; revert to the (redefined) function */
2601# define PNG_get_uint_32 (png_get_uint_32)
2602# define PNG_get_uint_16 (png_get_uint_16)
2603# define PNG_get_int_32 (png_get_int_32)
2604# endif
2605#endif
2606
2607#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2608PNG_EXPORT(242, void, png_set_check_for_invalid_index,
2609 (png_structrp png_ptr, int allowed));
2610# ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2611PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
2612 png_const_infop info_ptr));
2613# endif
2614#endif /* CHECK_FOR_INVALID_INDEX */
2615
2616/*******************************************************************************
2617 * Section 5: SIMPLIFIED API
2618 *******************************************************************************
2619 *
2620 * Please read the documentation in libpng-manual.txt (TODO: write said
2621 * documentation) if you don't understand what follows.
2622 *
2623 * The simplified API hides the details of both libpng and the PNG file format
2624 * itself. It allows PNG files to be read into a very limited number of
2625 * in-memory bitmap formats or to be written from the same formats. If these
2626 * formats do not accommodate your needs then you can, and should, use the more
2627 * sophisticated APIs above - these support a wide variety of in-memory formats
2628 * and a wide variety of sophisticated transformations to those formats as well
2629 * as a wide variety of APIs to manipulate ancillary information.
2630 *
2631 * To read a PNG file using the simplified API:
2632 *
2633 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2634 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2635 * (this is REQUIRED, your program may crash if you don't do it.)
2636 * 2) Call the appropriate png_image_begin_read... function.
2637 * 3) Set the png_image 'format' member to the required sample format.
2638 * 4) Allocate a buffer for the image and, if required, the color-map.
2639 * 5) Call png_image_finish_read to read the image and, if required, the
2640 * color-map into your buffers.
2641 *
2642 * There are no restrictions on the format of the PNG input itself; all valid
2643 * color types, bit depths, and interlace methods are acceptable, and the
2644 * input image is transformed as necessary to the requested in-memory format
2645 * during the png_image_finish_read() step. The only caveat is that if you
2646 * request a color-mapped image from a PNG that is full-color or makes
2647 * complex use of an alpha channel the transformation is extremely lossy and the
2648 * result may look terrible.
2649 *
2650 * To write a PNG file using the simplified API:
2651 *
2652 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2653 * 2) Initialize the members of the structure that describe the image, setting
2654 * the 'format' member to the format of the image samples.
2655 * 3) Call the appropriate png_image_write... function with a pointer to the
2656 * image and, if necessary, the color-map to write the PNG data.
2657 *
2658 * png_image is a structure that describes the in-memory format of an image
2659 * when it is being read or defines the in-memory format of an image that you
2660 * need to write:
2661 */
2662#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2663 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2664
2665#define PNG_IMAGE_VERSION 1
2666
2667typedef struct png_control *png_controlp;
2668typedef struct
2669{
2670 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2671 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2672 png_uint_32 width; /* Image width in pixels (columns) */
2673 png_uint_32 height; /* Image height in pixels (rows) */
2674 png_uint_32 format; /* Image format as defined below */
2675 png_uint_32 flags; /* A bit mask containing informational flags */
2676 png_uint_32 colormap_entries;
2677 /* Number of entries in the color-map */
2678
2679 /* In the event of an error or warning the following field will be set to a
2680 * non-zero value and the 'message' field will contain a '\0' terminated
2681 * string with the libpng error or warning message. If both warnings and
2682 * an error were encountered, only the error is recorded. If there
2683 * are multiple warnings, only the first one is recorded.
2684 *
2685 * The upper 30 bits of this value are reserved, the low two bits contain
2686 * a value as follows:
2687 */
2688# define PNG_IMAGE_WARNING 1
2689# define PNG_IMAGE_ERROR 2
2690 /*
2691 * The result is a two-bit code such that a value more than 1 indicates
2692 * a failure in the API just called:
2693 *
2694 * 0 - no warning or error
2695 * 1 - warning
2696 * 2 - error
2697 * 3 - error preceded by warning
2698 */
2699# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2700
2701 png_uint_32 warning_or_error;
2702
2703 char message[64];
2704} png_image, *png_imagep;
2705
2706/* The samples of the image have one to four channels whose components have
2707 * original values in the range 0 to 1.0:
2708 *
2709 * 1: A single gray or luminance channel (G).
2710 * 2: A gray/luminance channel and an alpha channel (GA).
2711 * 3: Three red, green, blue color channels (RGB).
2712 * 4: Three color channels and an alpha channel (RGBA).
2713 *
2714 * The components are encoded in one of two ways:
2715 *
2716 * a) As a small integer, value 0..255, contained in a single byte. For the
2717 * alpha channel the original value is simply value/255. For the color or
2718 * luminance channels the value is encoded according to the sRGB specification
2719 * and matches the 8-bit format expected by typical display devices.
2720 *
2721 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2722 * channel and are suitable for passing to color management software.
2723 *
2724 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2725 * channels can be converted to the original value by dividing by 65535; all
2726 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2727 * the sRGB specification. This encoding is identified by the
2728 * PNG_FORMAT_FLAG_LINEAR flag below.
2729 *
2730 * When the simplified API needs to convert between sRGB and linear colorspaces,
2731 * the actual sRGB transfer curve defined in the sRGB specification (see the
2732 * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2
2733 * approximation used elsewhere in libpng.
2734 *
2735 * When an alpha channel is present it is expected to denote pixel coverage
2736 * of the color or luminance channels and is returned as an associated alpha
2737 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2738 * value.
2739 *
2740 * The samples are either contained directly in the image data, between 1 and 8
2741 * bytes per pixel according to the encoding, or are held in a color-map indexed
2742 * by bytes in the image data. In the case of a color-map the color-map entries
2743 * are individual samples, encoded as above, and the image data has one byte per
2744 * pixel to select the relevant sample from the color-map.
2745 */
2746
2747/* PNG_FORMAT_*
2748 *
2749 * #defines to be used in png_image::format. Each #define identifies a
2750 * particular layout of sample data and, if present, alpha values. There are
2751 * separate defines for each of the two component encodings.
2752 *
2753 * A format is built up using single bit flag values. All combinations are
2754 * valid. Formats can be built up from the flag values or you can use one of
2755 * the predefined values below. When testing formats always use the FORMAT_FLAG
2756 * macros to test for individual features - future versions of the library may
2757 * add new flags.
2758 *
2759 * When reading or writing color-mapped images the format should be set to the
2760 * format of the entries in the color-map then png_image_{read,write}_colormap
2761 * called to read or write the color-map and set the format correctly for the
2762 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2763 *
2764 * NOTE: libpng can be built with particular features disabled. If you see
2765 * compiler errors because the definition of one of the following flags has been
2766 * compiled out it is because libpng does not have the required support. It is
2767 * possible, however, for the libpng configuration to enable the format on just
2768 * read or just write; in that case you may see an error at run time. You can
2769 * guard against this by checking for the definition of the appropriate
2770 * "_SUPPORTED" macro, one of:
2771 *
2772 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2773 */
2774#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2775#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2776#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2777#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2778
2779#ifdef PNG_FORMAT_BGR_SUPPORTED
2780# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2781#endif
2782
2783#ifdef PNG_FORMAT_AFIRST_SUPPORTED
2784# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2785#endif
2786
2787#define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */
2788
2789/* Commonly used formats have predefined macros.
2790 *
2791 * First the single byte (sRGB) formats:
2792 */
2793#define PNG_FORMAT_GRAY 0
2794#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2795#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2796#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2797#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2798#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2799#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2800#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2801#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2802
2803/* Then the linear 2-byte formats. When naming these "Y" is used to
2804 * indicate a luminance (gray) channel.
2805 */
2806#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2807#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2808#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2809#define PNG_FORMAT_LINEAR_RGB_ALPHA \
2810 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2811
2812/* With color-mapped formats the image data is one byte for each pixel, the byte
2813 * is an index into the color-map which is formatted as above. To obtain a
2814 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2815 * to one of the above definitions, or you can use one of the definitions below.
2816 */
2817#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2818#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2819#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2820#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2821#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2822#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2823
2824/* PNG_IMAGE macros
2825 *
2826 * These are convenience macros to derive information from a png_image
2827 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2828 * actual image sample values - either the entries in the color-map or the
2829 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2830 * for the pixels and will always return 1 for color-mapped formats. The
2831 * remaining macros return information about the rows in the image and the
2832 * complete image.
2833 *
2834 * NOTE: All the macros that take a png_image::format parameter are compile time
2835 * constants if the format parameter is, itself, a constant. Therefore these
2836 * macros can be used in array declarations and case labels where required.
2837 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2838 * they can be used in #if tests.
2839 *
2840 * First the information about the samples.
2841 */
2842#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2843 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2844 /* Return the total number of channels in a given format: 1..4 */
2845
2846#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2847 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2848 /* Return the size in bytes of a single component of a pixel or color-map
2849 * entry (as appropriate) in the image: 1 or 2.
2850 */
2851
2852#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2853 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2854 /* This is the size of the sample data for one sample. If the image is
2855 * color-mapped it is the size of one color-map entry (and image pixels are
2856 * one byte in size), otherwise it is the size of one image pixel.
2857 */
2858
2859#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2860 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2861 /* The maximum size of the color-map required by the format expressed in a
2862 * count of components. This can be used to compile-time allocate a
2863 * color-map:
2864 *
2865 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2866 *
2867 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2868 *
2869 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2870 * information from one of the png_image_begin_read_ APIs and dynamically
2871 * allocate the required memory.
2872 */
2873
2874/* Corresponding information about the pixels */
2875#define PNG_IMAGE_PIXEL_(test,fmt)\
2876 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2877
2878#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2879 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2880 /* The number of separate channels (components) in a pixel; 1 for a
2881 * color-mapped image.
2882 */
2883
2884#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2885 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2886 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2887 * image.
2888 */
2889
2890#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2891 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2892
2893/* Information about the whole row, or whole image */
2894#define PNG_IMAGE_ROW_STRIDE(image)\
2895 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2896 /* Return the total number of components in a single row of the image; this
2897 * is the minimum 'row stride', the minimum count of components between each
2898 * row. For a color-mapped image this is the minimum number of bytes in a
2899 * row.
2900 *
2901 * WARNING: this macro overflows for some images with more than one component
2902 * and very large image widths. libpng will refuse to process an image where
2903 * this macro would overflow.
2904 */
2905
2906#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2907 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2908 /* Return the size, in bytes, of an image buffer given a png_image and a row
2909 * stride - the number of components to leave space for in each row.
2910 *
2911 * WARNING: this macro overflows a 32-bit integer for some large PNG images,
2912 * libpng will refuse to process an image where such an overflow would occur.
2913 */
2914
2915#define PNG_IMAGE_SIZE(image)\
2916 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2917 /* Return the size, in bytes, of the image in memory given just a png_image;
2918 * the row stride is the minimum stride required for the image.
2919 */
2920
2921#define PNG_IMAGE_COLORMAP_SIZE(image)\
2922 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2923 /* Return the size, in bytes, of the color-map of this image. If the image
2924 * format is not a color-map format this will return a size sufficient for
2925 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2926 * you don't want to allocate a color-map in this case.
2927 */
2928
2929/* PNG_IMAGE_FLAG_*
2930 *
2931 * Flags containing additional information about the image are held in the
2932 * 'flags' field of png_image.
2933 */
2934#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2935 /* This indicates that the RGB values of the in-memory bitmap do not
2936 * correspond to the red, green and blue end-points defined by sRGB.
2937 */
2938
2939#define PNG_IMAGE_FLAG_FAST 0x02
2940 /* On write emphasise speed over compression; the resultant PNG file will be
2941 * larger but will be produced significantly faster, particular for large
2942 * images. Do not use this option for images which will be distributed, only
2943 * used it when producing intermediate files that will be read back in
2944 * repeatedly. For a typical 24-bit image the option will double the read
2945 * speed at the cost of increasing the image size by 25%, however for many
2946 * more compressible images the PNG file can be 10 times larger with only a
2947 * slight speed gain.
2948 */
2949
2950#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
2951 /* On read if the image is a 16-bit per component image and there is no gAMA
2952 * or sRGB chunk assume that the components are sRGB encoded. Notice that
2953 * images output by the simplified API always have gamma information; setting
2954 * this flag only affects the interpretation of 16-bit images from an
2955 * external source. It is recommended that the application expose this flag
2956 * to the user; the user can normally easily recognize the difference between
2957 * linear and sRGB encoding. This flag has no effect on write - the data
2958 * passed to the write APIs must have the correct encoding (as defined
2959 * above.)
2960 *
2961 * If the flag is not set (the default) input 16-bit per component data is
2962 * assumed to be linear.
2963 *
2964 * NOTE: the flag can only be set after the png_image_begin_read_ call,
2965 * because that call initializes the 'flags' field.
2966 */
2967
2968#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
2969/* READ APIs
2970 * ---------
2971 *
2972 * The png_image passed to the read APIs must have been initialized by setting
2973 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
2974 */
2975#ifdef PNG_STDIO_SUPPORTED
2976PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
2977 const char *file_name));
2978 /* The named file is opened for read and the image header is filled in
2979 * from the PNG header in the file.
2980 */
2981
2982PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
2983 FILE* file));
2984 /* The PNG header is read from the stdio FILE object. */
2985#endif /* STDIO */
2986
2987PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
2988 png_const_voidp memory, size_t size));
2989 /* The PNG header is read from the given memory buffer. */
2990
2991PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
2992 png_const_colorp background, void *buffer, png_int_32 row_stride,
2993 void *colormap));
2994 /* Finish reading the image into the supplied buffer and clean up the
2995 * png_image structure.
2996 *
2997 * row_stride is the step, in byte or 2-byte units as appropriate,
2998 * between adjacent rows. A positive stride indicates that the top-most row
2999 * is first in the buffer - the normal top-down arrangement. A negative
3000 * stride indicates that the bottom-most row is first in the buffer.
3001 *
3002 * background need only be supplied if an alpha channel must be removed from
3003 * a png_byte format and the removal is to be done by compositing on a solid
3004 * color; otherwise it may be NULL and any composition will be done directly
3005 * onto the buffer. The value is an sRGB color to use for the background,
3006 * for grayscale output the green channel is used.
3007 *
3008 * background must be supplied when an alpha channel must be removed from a
3009 * single byte color-mapped output format, in other words if:
3010 *
3011 * 1) The original format from png_image_begin_read_from_* had
3012 * PNG_FORMAT_FLAG_ALPHA set.
3013 * 2) The format set by the application does not.
3014 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3015 * PNG_FORMAT_FLAG_LINEAR *not* set.
3016 *
3017 * For linear output removing the alpha channel is always done by compositing
3018 * on black and background is ignored.
3019 *
3020 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3021 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3022 * image->colormap_entries will be updated to the actual number of entries
3023 * written to the colormap; this may be less than the original value.
3024 */
3025
3026PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3027 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3028 * NULL. May be called at any time after the structure is initialized.
3029 */
3030#endif /* SIMPLIFIED_READ */
3031
3032#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3033/* WRITE APIS
3034 * ----------
3035 * For write you must initialize a png_image structure to describe the image to
3036 * be written. To do this use memset to set the whole structure to 0 then
3037 * initialize fields describing your image.
3038 *
3039 * version: must be set to PNG_IMAGE_VERSION
3040 * opaque: must be initialized to NULL
3041 * width: image width in pixels
3042 * height: image height in rows
3043 * format: the format of the data (image and color-map) you wish to write
3044 * flags: set to 0 unless one of the defined flags applies; set
3045 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3046 * values do not correspond to the colors in sRGB.
3047 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3048 */
3049#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3050PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3051 const char *file, int convert_to_8bit, const void *buffer,
3052 png_int_32 row_stride, const void *colormap));
3053 /* Write the image to the named file. */
3054
3055PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3056 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3057 const void *colormap));
3058 /* Write the image to the given (FILE*). */
3059#endif /* SIMPLIFIED_WRITE_STDIO */
3060
3061/* With all write APIs if image is in one of the linear formats with 16-bit
3062 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3063 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3064 * encoded PNG file is written.
3065 *
3066 * With color-mapped data formats the colormap parameter point to a color-map
3067 * with at least image->colormap_entries encoded in the specified format. If
3068 * the format is linear the written PNG color-map will be converted to sRGB
3069 * regardless of the convert_to_8_bit flag.
3070 *
3071 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3072 * from one row to the next in component sized units (1 or 2 bytes) and if
3073 * negative indicates a bottom-up row layout in the buffer. If row_stride is
3074 * zero, libpng will calculate it for you from the image width and number of
3075 * channels.
3076 *
3077 * Note that the write API does not support interlacing, sub-8-bit pixels or
3078 * most ancillary chunks. If you need to write text chunks (e.g. for copyright
3079 * notices) you need to use one of the other APIs.
3080 */
3081
3082PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
3083 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
3084 const void *buffer, png_int_32 row_stride, const void *colormap));
3085 /* Write the image to the given memory buffer. The function both writes the
3086 * whole PNG data stream to *memory and updates *memory_bytes with the count
3087 * of bytes written.
3088 *
3089 * 'memory' may be NULL. In this case *memory_bytes is not read however on
3090 * success the number of bytes which would have been written will still be
3091 * stored in *memory_bytes. On failure *memory_bytes will contain 0.
3092 *
3093 * If 'memory' is not NULL it must point to memory[*memory_bytes] of
3094 * writeable memory.
3095 *
3096 * If the function returns success memory[*memory_bytes] (if 'memory' is not
3097 * NULL) contains the written PNG data. *memory_bytes will always be less
3098 * than or equal to the original value.
3099 *
3100 * If the function returns false and *memory_bytes was not changed an error
3101 * occurred during write. If *memory_bytes was changed, or is not 0 if
3102 * 'memory' was NULL, the write would have succeeded but for the memory
3103 * buffer being too small. *memory_bytes contains the required number of
3104 * bytes and will be bigger that the original value.
3105 */
3106
3107#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
3108 row_stride, colormap)\
3109 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
3110 row_stride, colormap)
3111 /* Return the amount of memory in 'size' required to compress this image.
3112 * The png_image structure 'image' must be filled in as in the above
3113 * function and must not be changed before the actual write call, the buffer
3114 * and all other parameters must also be identical to that in the final
3115 * write call. The 'size' variable need not be initialized.
3116 *
3117 * NOTE: the macro returns true/false, if false is returned 'size' will be
3118 * set to zero and the write failed and probably will fail if tried again.
3119 */
3120
3121/* You can pre-allocate the buffer by making sure it is of sufficient size
3122 * regardless of the amount of compression achieved. The buffer size will
3123 * always be bigger than the original image and it will never be filled. The
3124 * following macros are provided to assist in allocating the buffer.
3125 */
3126#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
3127 /* The number of uncompressed bytes in the PNG byte encoding of the image;
3128 * uncompressing the PNG IDAT data will give this number of bytes.
3129 *
3130 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
3131 * macro can because of the extra bytes used in the PNG byte encoding. You
3132 * need to avoid this macro if your image size approaches 2^30 in width or
3133 * height. The same goes for the remainder of these macros; they all produce
3134 * bigger numbers than the actual in-memory image size.
3135 */
3136#ifndef PNG_ZLIB_MAX_SIZE
3137# define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
3138 /* An upper bound on the number of compressed bytes given 'b' uncompressed
3139 * bytes. This is based on deflateBounds() in zlib; different
3140 * implementations of zlib compression may conceivably produce more data so
3141 * if your zlib implementation is not zlib itself redefine this macro
3142 * appropriately.
3143 */
3144#endif
3145
3146#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
3147 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
3148 /* An upper bound on the size of the data in the PNG IDAT chunks. */
3149
3150#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
3151 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
3152 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
3153 12U+3U*(image).colormap_entries/*PLTE data*/+\
3154 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
3155 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
3156 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
3157 /* A helper for the following macro; if your compiler cannot handle the
3158 * following macro use this one with the result of
3159 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
3160 * compilers should handle this just fine.)
3161 */
3162
3163#define PNG_IMAGE_PNG_SIZE_MAX(image)\
3164 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
3165 /* An upper bound on the total length of the PNG data stream for 'image'.
3166 * The result is of type png_alloc_size_t, on 32-bit systems this may
3167 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
3168 * run out of buffer space but return a corrected size which should work.
3169 */
3170#endif /* SIMPLIFIED_WRITE */
3171/*******************************************************************************
3172 * END OF SIMPLIFIED API
3173 ******************************************************************************/
3174#endif /* SIMPLIFIED_{READ|WRITE} */
3175
3176/*******************************************************************************
3177 * Section 6: IMPLEMENTATION OPTIONS
3178 *******************************************************************************
3179 *
3180 * Support for arbitrary implementation-specific optimizations. The API allows
3181 * particular options to be turned on or off. 'Option' is the number of the
3182 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3183 * by the PNG_OPTION_ defines below.
3184 *
3185 * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions,
3186 * are detected at run time, however sometimes it may be impossible
3187 * to do this in user mode, in which case it is necessary to discover
3188 * the capabilities in an OS specific way. Such capabilities are
3189 * listed here when libpng has support for them and must be turned
3190 * ON by the application if present.
3191 *
3192 * SOFTWARE: sometimes software optimizations actually result in performance
3193 * decrease on some architectures or systems, or with some sets of
3194 * PNG images. 'Software' options allow such optimizations to be
3195 * selected at run time.
3196 */
3197#ifdef PNG_SET_OPTION_SUPPORTED
3198#ifdef PNG_ARM_NEON_API_SUPPORTED
3199# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3200#endif
3201#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3202#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3203#ifdef PNG_MIPS_MSA_API_SUPPORTED
3204# define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */
3205#endif
3206#ifdef PNG_DISABLE_ADLER32_CHECK_SUPPORTED
3207# define PNG_IGNORE_ADLER32 8 /* SOFTWARE: disable Adler32 check on IDAT */
3208#endif
3209#ifdef PNG_POWERPC_VSX_API_SUPPORTED
3210# define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions
3211 * supported */
3212#endif
3213#ifdef PNG_MIPS_MMI_API_SUPPORTED
3214# define PNG_MIPS_MMI 12 /* HARDWARE: MIPS MMI SIMD instructions supported */
3215#endif
3216
3217#define PNG_OPTION_NEXT 14 /* Next option - numbers must be even */
3218
3219/* Return values: NOTE: there are four values and 'off' is *not* zero */
3220#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3221#define PNG_OPTION_INVALID 1 /* Option number out of range */
3222#define PNG_OPTION_OFF 2
3223#define PNG_OPTION_ON 3
3224
3225PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3226 int onoff));
3227#endif /* SET_OPTION */
3228
3229/*******************************************************************************
3230 * END OF HARDWARE AND SOFTWARE OPTIONS
3231 ******************************************************************************/
3232
3233/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3234 * defs, and in scripts/symbols.def.
3235 */
3236
3237/* The last ordinal number (this is the *last* one already used; the next
3238 * one to use is one more than this.)
3239 */
3240#ifdef PNG_EXPORT_LAST_ORDINAL
3241 PNG_EXPORT_LAST_ORDINAL(249);
3242#endif
3243
3244#ifdef __cplusplus
3245}
3246#endif
3247
3248#endif /* PNG_VERSION_INFO_ONLY */
3249/* Do not put anything past this line */
3250#endif /* PNG_H */
3251