1 
2/* png.h - header file for PNG reference library 
3 * 
4 * libpng version 1.6.37 - April 14, 2019 
5 * 
6 * Copyright (c) 2018-2019 Cosmin Truta 
7 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson 
8 * Copyright (c) 1996-1997 Andreas Dilger 
9 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc. 
10 * 
11 * This code is released under the libpng license. (See LICENSE, below.) 
12 * 
13 * Authors and maintainers: 
14 * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat 
15 * libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger 
16 * libpng versions 0.97, January 1998, through 1.6.35, July 2018: 
17 * Glenn Randers-Pehrson 
18 * libpng versions 1.6.36, December 2018, through 1.6.37, April 2019: 
19 * Cosmin Truta 
20 * See also "Contributing Authors", below. 
21 */ 
22 
23/* 
24 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE 
25 * ========================================= 
26 * 
27 * PNG Reference Library License version 2 
28 * --------------------------------------- 
29 * 
30 * * Copyright (c) 1995-2019 The PNG Reference Library Authors. 
31 * * Copyright (c) 2018-2019 Cosmin Truta. 
32 * * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson. 
33 * * Copyright (c) 1996-1997 Andreas Dilger. 
34 * * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc. 
35 * 
36 * The software is supplied "as is", without warranty of any kind, 
37 * express or implied, including, without limitation, the warranties 
38 * of merchantability, fitness for a particular purpose, title, and 
39 * non-infringement. In no event shall the Copyright owners, or 
40 * anyone distributing the software, be liable for any damages or 
41 * other liability, whether in contract, tort or otherwise, arising 
42 * from, out of, or in connection with the software, or the use or 
43 * other dealings in the software, even if advised of the possibility 
44 * of such damage. 
45 * 
46 * Permission is hereby granted to use, copy, modify, and distribute 
47 * this software, or portions hereof, for any purpose, without fee, 
48 * subject to the following restrictions: 
49 * 
50 * 1. The origin of this software must not be misrepresented; you 
51 * must not claim that you wrote the original software. If you 
52 * use this software in a product, an acknowledgment in the product 
53 * documentation would be appreciated, but is not required. 
54 * 
55 * 2. Altered source versions must be plainly marked as such, and must 
56 * not be misrepresented as being the original software. 
57 * 
58 * 3. This Copyright notice may not be removed or altered from any 
59 * source or altered source distribution. 
60 * 
61 * 
62 * PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35) 
63 * ----------------------------------------------------------------------- 
64 * 
65 * libpng versions 1.0.7, July 1, 2000, through 1.6.35, July 15, 2018 are 
66 * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are 
67 * derived from libpng-1.0.6, and are distributed according to the same 
68 * disclaimer and license as libpng-1.0.6 with the following individuals 
69 * added to the list of Contributing Authors: 
70 * 
71 * Simon-Pierre Cadieux 
72 * Eric S. Raymond 
73 * Mans Rullgard 
74 * Cosmin Truta 
75 * Gilles Vollant 
76 * James Yu 
77 * Mandar Sahastrabuddhe 
78 * Google Inc. 
79 * Vadim Barkov 
80 * 
81 * and with the following additions to the disclaimer: 
82 * 
83 * There is no warranty against interference with your enjoyment of 
84 * the library or against infringement. There is no warranty that our 
85 * efforts or the library will fulfill any of your particular purposes 
86 * or needs. This library is provided with all faults, and the entire 
87 * risk of satisfactory quality, performance, accuracy, and effort is 
88 * with the user. 
89 * 
90 * Some files in the "contrib" directory and some configure-generated 
91 * files that are distributed with libpng have other copyright owners, and 
92 * are released under other open source licenses. 
93 * 
94 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are 
95 * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from 
96 * libpng-0.96, and are distributed according to the same disclaimer and 
97 * license as libpng-0.96, with the following individuals added to the 
98 * list of Contributing Authors: 
99 * 
100 * Tom Lane 
101 * Glenn Randers-Pehrson 
102 * Willem van Schaik 
103 * 
104 * libpng versions 0.89, June 1996, through 0.96, May 1997, are 
105 * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88, 
106 * and are distributed according to the same disclaimer and license as 
107 * libpng-0.88, with the following individuals added to the list of 
108 * Contributing Authors: 
109 * 
110 * John Bowler 
111 * Kevin Bracey 
112 * Sam Bushell 
113 * Magnus Holmgren 
114 * Greg Roelofs 
115 * Tom Tanner 
116 * 
117 * Some files in the "scripts" directory have other copyright owners, 
118 * but are released under this license. 
119 * 
120 * libpng versions 0.5, May 1995, through 0.88, January 1996, are 
121 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc. 
122 * 
123 * For the purposes of this copyright and license, "Contributing Authors" 
124 * is defined as the following set of individuals: 
125 * 
126 * Andreas Dilger 
127 * Dave Martindale 
128 * Guy Eric Schalnat 
129 * Paul Schmidt 
130 * Tim Wegner 
131 * 
132 * The PNG Reference Library is supplied "AS IS". The Contributing 
133 * Authors and Group 42, Inc. disclaim all warranties, expressed or 
134 * implied, including, without limitation, the warranties of 
135 * merchantability and of fitness for any purpose. The Contributing 
136 * Authors and Group 42, Inc. assume no liability for direct, indirect, 
137 * incidental, special, exemplary, or consequential damages, which may 
138 * result from the use of the PNG Reference Library, even if advised of 
139 * the possibility of such damage. 
140 * 
141 * Permission is hereby granted to use, copy, modify, and distribute this 
142 * source code, or portions hereof, for any purpose, without fee, subject 
143 * to the following restrictions: 
144 * 
145 * 1. The origin of this source code must not be misrepresented. 
146 * 
147 * 2. Altered versions must be plainly marked as such and must not 
148 * be misrepresented as being the original source. 
149 * 
150 * 3. This Copyright notice may not be removed or altered from any 
151 * source or altered source distribution. 
152 * 
153 * The Contributing Authors and Group 42, Inc. specifically permit, 
154 * without fee, and encourage the use of this source code as a component 
155 * to supporting the PNG file format in commercial products. If you use 
156 * this source code in a product, acknowledgment is not required but would 
157 * be appreciated. 
158 * 
159 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE. 
160 * 
161 * TRADEMARK 
162 * ========= 
163 * 
164 * The name "libpng" has not been registered by the Copyright owners 
165 * as a trademark in any jurisdiction. However, because libpng has 
166 * been distributed and maintained world-wide, continually since 1995, 
167 * the Copyright owners claim "common-law trademark protection" in any 
168 * jurisdiction where common-law trademark is recognized. 
169 */ 
170 
171/* 
172 * A "png_get_copyright" function is available, for convenient use in "about" 
173 * boxes and the like: 
174 * 
175 * printf("%s", png_get_copyright(NULL)); 
176 * 
177 * Also, the PNG logo (in PNG format, of course) is supplied in the 
178 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31). 
179 */ 
180 
181/* 
182 * The contributing authors would like to thank all those who helped 
183 * with testing, bug fixes, and patience. This wouldn't have been 
184 * possible without all of you. 
185 * 
186 * Thanks to Frank J. T. Wojcik for helping with the documentation. 
187 */ 
188 
189/* Note about libpng version numbers: 
190 * 
191 * Due to various miscommunications, unforeseen code incompatibilities 
192 * and occasional factors outside the authors' control, version numbering 
193 * on the library has not always been consistent and straightforward. 
194 * The following table summarizes matters since version 0.89c, which was 
195 * the first widely used release: 
196 * 
197 * source png.h png.h shared-lib 
198 * version string int version 
199 * ------- ------ ----- ---------- 
200 * 0.89c "1.0 beta 3" 0.89 89 1.0.89 
201 * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90] 
202 * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95] 
203 * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96] 
204 * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97] 
205 * 0.97c 0.97 97 2.0.97 
206 * 0.98 0.98 98 2.0.98 
207 * 0.99 0.99 98 2.0.99 
208 * 0.99a-m 0.99 99 2.0.99 
209 * 1.00 1.00 100 2.1.0 [100 should be 10000] 
210 * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000] 
211 * 1.0.1 png.h string is 10001 2.1.0 
212 * 1.0.1a-e identical to the 10002 from here on, the shared library 
213 * 1.0.2 source version) 10002 is 2.V where V is the source code 
214 * 1.0.2a-b 10003 version, except as noted. 
215 * 1.0.3 10003 
216 * 1.0.3a-d 10004 
217 * 1.0.4 10004 
218 * 1.0.4a-f 10005 
219 * 1.0.5 (+ 2 patches) 10005 
220 * 1.0.5a-d 10006 
221 * 1.0.5e-r 10100 (not source compatible) 
222 * 1.0.5s-v 10006 (not binary compatible) 
223 * 1.0.6 (+ 3 patches) 10006 (still binary incompatible) 
224 * 1.0.6d-f 10007 (still binary incompatible) 
225 * 1.0.6g 10007 
226 * 1.0.6h 10007 10.6h (testing xy.z so-numbering) 
227 * 1.0.6i 10007 10.6i 
228 * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0) 
229 * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible) 
230 * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible) 
231 * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible) 
232 * 1.0.7 1 10007 (still compatible) 
233 * ... 
234 * 1.0.69 10 10069 10.so.0.69[.0] 
235 * ... 
236 * 1.2.59 13 10259 12.so.0.59[.0] 
237 * ... 
238 * 1.4.20 14 10420 14.so.0.20[.0] 
239 * ... 
240 * 1.5.30 15 10530 15.so.15.30[.0] 
241 * ... 
242 * 1.6.37 16 10637 16.so.16.37[.0] 
243 * 
244 * Henceforth the source version will match the shared-library major and 
245 * minor numbers; the shared-library major version number will be used for 
246 * changes in backward compatibility, as it is intended. 
247 * The PNG_LIBPNG_VER macro, which is not used within libpng but is 
248 * available for applications, is an unsigned integer of the form XYYZZ 
249 * corresponding to the source version X.Y.Z (leading zeros in Y and Z). 
250 * Beta versions were given the previous public release number plus a 
251 * letter, until version 1.0.6j; from then on they were given the upcoming 
252 * public release number plus "betaNN" or "rcNN". 
253 * 
254 * Binary incompatibility exists only when applications make direct access 
255 * to the info_ptr or png_ptr members through png.h, and the compiled 
256 * application is loaded with a different version of the library. 
257 * 
258 * DLLNUM will change each time there are forward or backward changes 
259 * in binary compatibility (e.g., when a new feature is added). 
260 * 
261 * See libpng.txt or libpng.3 for more information. The PNG specification 
262 * is available as a W3C Recommendation and as an ISO/IEC Standard; see 
263 * <https://www.w3.org/TR/2003/REC-PNG-20031110/> 
264 */ 
265 
266#ifndef PNG_H 
267#define PNG_H 
268 
269/* This is not the place to learn how to use libpng. The file libpng-manual.txt 
270 * describes how to use libpng, and the file example.c summarizes it 
271 * with some code on which to build. This file is useful for looking 
272 * at the actual function definitions and structure components. If that 
273 * file has been stripped from your copy of libpng, you can find it at 
274 * <http://www.libpng.org/pub/png/libpng-manual.txt> 
275 * 
276 * If you just need to read a PNG file and don't want to read the documentation 
277 * skip to the end of this file and read the section entitled 'simplified API'. 
278 */ 
279 
280/* Version information for png.h - this should match the version in png.c */ 
281#define PNG_LIBPNG_VER_STRING "1.6.37" 
282#define PNG_HEADER_VERSION_STRING " libpng version 1.6.37 - April 14, 2019\n" 
283 
284#define PNG_LIBPNG_VER_SONUM 16 
285#define PNG_LIBPNG_VER_DLLNUM 16 
286 
287/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */ 
288#define PNG_LIBPNG_VER_MAJOR 1 
289#define PNG_LIBPNG_VER_MINOR 6 
290#define PNG_LIBPNG_VER_RELEASE 37 
291 
292/* This should be zero for a public release, or non-zero for a 
293 * development version. [Deprecated] 
294 */ 
295#define PNG_LIBPNG_VER_BUILD 0 
296 
297/* Release Status */ 
298#define PNG_LIBPNG_BUILD_ALPHA 1 
299#define PNG_LIBPNG_BUILD_BETA 2 
300#define PNG_LIBPNG_BUILD_RC 3 
301#define PNG_LIBPNG_BUILD_STABLE 4 
302#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7 
303 
304/* Release-Specific Flags */ 
305#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with 
306 PNG_LIBPNG_BUILD_STABLE only */ 
307#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with 
308 PNG_LIBPNG_BUILD_SPECIAL */ 
309#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with 
310 PNG_LIBPNG_BUILD_PRIVATE */ 
311 
312#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE 
313 
314/* Careful here. At one time, Guy wanted to use 082, but that 
315 * would be octal. We must not include leading zeros. 
316 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here 
317 * (only version 1.0.0 was mis-numbered 100 instead of 10000). 
318 * From version 1.0.1 it is: 
319 * XXYYZZ, where XX=major, YY=minor, ZZ=release 
320 */ 
321#define PNG_LIBPNG_VER 10637 /* 1.6.37 */ 
322 
323/* Library configuration: these options cannot be changed after 
324 * the library has been built. 
325 */ 
326#ifndef PNGLCONF_H 
327/* If pnglibconf.h is missing, you can 
328 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h 
329 */ 
330# include "pnglibconf.h" 
331#endif 
332 
333#define PNG_APNG_SUPPORTED 
334#define PNG_READ_APNG_SUPPORTED 
335#define PNG_WRITE_APNG_SUPPORTED 
336 
337#ifndef PNG_VERSION_INFO_ONLY 
338/* Machine specific configuration. */ 
339# include "pngconf.h" 
340#endif 
341 
342/* 
343 * Added at libpng-1.2.8 
344 * 
345 * Ref MSDN: Private as priority over Special 
346 * VS_FF_PRIVATEBUILD File *was not* built using standard release 
347 * procedures. If this value is given, the StringFileInfo block must 
348 * contain a PrivateBuild string. 
349 * 
350 * VS_FF_SPECIALBUILD File *was* built by the original company using 
351 * standard release procedures but is a variation of the standard 
352 * file of the same version number. If this value is given, the 
353 * StringFileInfo block must contain a SpecialBuild string. 
354 */ 
355 
356#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */ 
357# define PNG_LIBPNG_BUILD_TYPE \ 
358 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE) 
359#else 
360# ifdef PNG_LIBPNG_SPECIALBUILD 
361# define PNG_LIBPNG_BUILD_TYPE \ 
362 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL) 
363# else 
364# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE) 
365# endif 
366#endif 
367 
368#ifndef PNG_VERSION_INFO_ONLY 
369 
370/* Inhibit C++ name-mangling for libpng functions but not for system calls. */ 
371#ifdef __cplusplus 
372extern "C"
373#endif /* __cplusplus */ 
374 
375/* Version information for C files, stored in png.c. This had better match 
376 * the version above. 
377 */ 
378#define png_libpng_ver png_get_header_ver(NULL) 
379 
380/* This file is arranged in several sections: 
381 * 
382 * 1. [omitted] 
383 * 2. Any configuration options that can be specified by for the application 
384 * code when it is built. (Build time configuration is in pnglibconf.h) 
385 * 3. Type definitions (base types are defined in pngconf.h), structure 
386 * definitions. 
387 * 4. Exported library functions. 
388 * 5. Simplified API. 
389 * 6. Implementation options. 
390 * 
391 * The library source code has additional files (principally pngpriv.h) that 
392 * allow configuration of the library. 
393 */ 
394 
395/* Section 1: [omitted] */ 
396 
397/* Section 2: run time configuration 
398 * See pnglibconf.h for build time configuration 
399 * 
400 * Run time configuration allows the application to choose between 
401 * implementations of certain arithmetic APIs. The default is set 
402 * at build time and recorded in pnglibconf.h, but it is safe to 
403 * override these (and only these) settings. Note that this won't 
404 * change what the library does, only application code, and the 
405 * settings can (and probably should) be made on a per-file basis 
406 * by setting the #defines before including png.h 
407 * 
408 * Use macros to read integers from PNG data or use the exported 
409 * functions? 
410 * PNG_USE_READ_MACROS: use the macros (see below) Note that 
411 * the macros evaluate their argument multiple times. 
412 * PNG_NO_USE_READ_MACROS: call the relevant library function. 
413 * 
414 * Use the alternative algorithm for compositing alpha samples that 
415 * does not use division? 
416 * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division' 
417 * algorithm. 
418 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm. 
419 * 
420 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is 
421 * false? 
422 * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error 
423 * APIs to png_warning. 
424 * Otherwise the calls are mapped to png_error. 
425 */ 
426 
427/* Section 3: type definitions, including structures and compile time 
428 * constants. 
429 * See pngconf.h for base types that vary by machine/system 
430 */ 
431 
432#ifdef PNG_APNG_SUPPORTED 
433/* dispose_op flags from inside fcTL */ 
434#define PNG_DISPOSE_OP_NONE 0x00U 
435#define PNG_DISPOSE_OP_BACKGROUND 0x01U 
436#define PNG_DISPOSE_OP_PREVIOUS 0x02U 
437 
438/* blend_op flags from inside fcTL */ 
439#define PNG_BLEND_OP_SOURCE 0x00U 
440#define PNG_BLEND_OP_OVER 0x01U 
441#endif /* PNG_APNG_SUPPORTED */ 
442 
443/* This triggers a compiler error in png.c, if png.c and png.h 
444 * do not agree upon the version number. 
445 */ 
446typedef char* png_libpng_version_1_6_37
447 
448/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info. 
449 * 
450 * png_struct is the cache of information used while reading or writing a single 
451 * PNG file. One of these is always required, although the simplified API 
452 * (below) hides the creation and destruction of it. 
453 */ 
454typedef struct png_struct_def png_struct
455typedef const png_struct * png_const_structp
456typedef png_struct * png_structp
457typedef png_struct * * png_structpp
458 
459/* png_info contains information read from or to be written to a PNG file. One 
460 * or more of these must exist while reading or creating a PNG file. The 
461 * information is not used by libpng during read but is used to control what 
462 * gets written when a PNG file is created. "png_get_" function calls read 
463 * information during read and "png_set_" functions calls write information 
464 * when creating a PNG. 
465 * been moved into a separate header file that is not accessible to 
466 * applications. Read libpng-manual.txt or libpng.3 for more info. 
467 */ 
468typedef struct png_info_def png_info
469typedef png_info * png_infop
470typedef const png_info * png_const_infop
471typedef png_info * * png_infopp
472 
473/* Types with names ending 'p' are pointer types. The corresponding types with 
474 * names ending 'rp' are identical pointer types except that the pointer is 
475 * marked 'restrict', which means that it is the only pointer to the object 
476 * passed to the function. Applications should not use the 'restrict' types; 
477 * it is always valid to pass 'p' to a pointer with a function argument of the 
478 * corresponding 'rp' type. Different compilers have different rules with 
479 * regard to type matching in the presence of 'restrict'. For backward 
480 * compatibility libpng callbacks never have 'restrict' in their parameters and, 
481 * consequentially, writing portable application code is extremely difficult if 
482 * an attempt is made to use 'restrict'. 
483 */ 
484typedef png_struct * PNG_RESTRICT png_structrp
485typedef const png_struct * PNG_RESTRICT png_const_structrp
486typedef png_info * PNG_RESTRICT png_inforp
487typedef const png_info * PNG_RESTRICT png_const_inforp
488 
489/* Three color definitions. The order of the red, green, and blue, (and the 
490 * exact size) is not important, although the size of the fields need to 
491 * be png_byte or png_uint_16 (as defined below). 
492 */ 
493typedef struct png_color_struct 
494
495 png_byte red
496 png_byte green
497 png_byte blue
498} png_color
499typedef png_color * png_colorp
500typedef const png_color * png_const_colorp
501typedef png_color * * png_colorpp
502 
503typedef struct png_color_16_struct 
504
505 png_byte index; /* used for palette files */ 
506 png_uint_16 red; /* for use in red green blue files */ 
507 png_uint_16 green
508 png_uint_16 blue
509 png_uint_16 gray; /* for use in grayscale files */ 
510} png_color_16
511typedef png_color_16 * png_color_16p
512typedef const png_color_16 * png_const_color_16p
513typedef png_color_16 * * png_color_16pp
514 
515typedef struct png_color_8_struct 
516
517 png_byte red; /* for use in red green blue files */ 
518 png_byte green
519 png_byte blue
520 png_byte gray; /* for use in grayscale files */ 
521 png_byte alpha; /* for alpha channel files */ 
522} png_color_8
523typedef png_color_8 * png_color_8p
524typedef const png_color_8 * png_const_color_8p
525typedef png_color_8 * * png_color_8pp
526 
527/* 
528 * The following two structures are used for the in-core representation 
529 * of sPLT chunks. 
530 */ 
531typedef struct png_sPLT_entry_struct 
532
533 png_uint_16 red
534 png_uint_16 green
535 png_uint_16 blue
536 png_uint_16 alpha
537 png_uint_16 frequency
538} png_sPLT_entry
539typedef png_sPLT_entry * png_sPLT_entryp
540typedef const png_sPLT_entry * png_const_sPLT_entryp
541typedef png_sPLT_entry * * png_sPLT_entrypp
542 
543/* When the depth of the sPLT palette is 8 bits, the color and alpha samples 
544 * occupy the LSB of their respective members, and the MSB of each member 
545 * is zero-filled. The frequency member always occupies the full 16 bits. 
546 */ 
547 
548typedef struct png_sPLT_struct 
549
550 png_charp name; /* palette name */ 
551 png_byte depth; /* depth of palette samples */ 
552 png_sPLT_entryp entries; /* palette entries */ 
553 png_int_32 nentries; /* number of palette entries */ 
554} png_sPLT_t
555typedef png_sPLT_t * png_sPLT_tp
556typedef const png_sPLT_t * png_const_sPLT_tp
557typedef png_sPLT_t * * png_sPLT_tpp
558 
559#ifdef PNG_TEXT_SUPPORTED 
560/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file, 
561 * and whether that contents is compressed or not. The "key" field 
562 * points to a regular zero-terminated C string. The "text" fields can be a 
563 * regular C string, an empty string, or a NULL pointer. 
564 * However, the structure returned by png_get_text() will always contain 
565 * the "text" field as a regular zero-terminated C string (possibly 
566 * empty), never a NULL pointer, so it can be safely used in printf() and 
567 * other string-handling functions. Note that the "itxt_length", "lang", and 
568 * "lang_key" members of the structure only exist when the library is built 
569 * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by 
570 * default without iTXt support. Also note that when iTXt *is* supported, 
571 * the "lang" and "lang_key" fields contain NULL pointers when the 
572 * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or 
573 * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the 
574 * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag" 
575 * which is always 0 or 1, or its "compression method" which is always 0. 
576 */ 
577typedef struct png_text_struct 
578
579 int compression; /* compression value: 
580 -1: tEXt, none 
581 0: zTXt, deflate 
582 1: iTXt, none 
583 2: iTXt, deflate */ 
584 png_charp key; /* keyword, 1-79 character description of "text" */ 
585 png_charp text; /* comment, may be an empty string (ie "") 
586 or a NULL pointer */ 
587 size_t text_length; /* length of the text string */ 
588 size_t itxt_length; /* length of the itxt string */ 
589 png_charp lang; /* language code, 0-79 characters 
590 or a NULL pointer */ 
591 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more 
592 chars or a NULL pointer */ 
593} png_text
594typedef png_text * png_textp
595typedef const png_text * png_const_textp
596typedef png_text * * png_textpp
597#endif 
598 
599/* Supported compression types for text in PNG files (tEXt, and zTXt). 
600 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */ 
601#define PNG_TEXT_COMPRESSION_NONE_WR -3 
602#define PNG_TEXT_COMPRESSION_zTXt_WR -2 
603#define PNG_TEXT_COMPRESSION_NONE -1 
604#define PNG_TEXT_COMPRESSION_zTXt 0 
605#define PNG_ITXT_COMPRESSION_NONE 1 
606#define PNG_ITXT_COMPRESSION_zTXt 2 
607#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */ 
608 
609/* png_time is a way to hold the time in an machine independent way. 
610 * Two conversions are provided, both from time_t and struct tm. There 
611 * is no portable way to convert to either of these structures, as far 
612 * as I know. If you know of a portable way, send it to me. As a side 
613 * note - PNG has always been Year 2000 compliant! 
614 */ 
615typedef struct png_time_struct 
616
617 png_uint_16 year; /* full year, as in, 1995 */ 
618 png_byte month; /* month of year, 1 - 12 */ 
619 png_byte day; /* day of month, 1 - 31 */ 
620 png_byte hour; /* hour of day, 0 - 23 */ 
621 png_byte minute; /* minute of hour, 0 - 59 */ 
622 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */ 
623} png_time
624typedef png_time * png_timep
625typedef const png_time * png_const_timep
626typedef png_time * * png_timepp
627 
628#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\ 
629 defined(PNG_USER_CHUNKS_SUPPORTED) 
630/* png_unknown_chunk is a structure to hold queued chunks for which there is 
631 * no specific support. The idea is that we can use this to queue 
632 * up private chunks for output even though the library doesn't actually 
633 * know about their semantics. 
634 * 
635 * The data in the structure is set by libpng on read and used on write. 
636 */ 
637typedef struct png_unknown_chunk_t 
638
639 png_byte name[5]; /* Textual chunk name with '\0' terminator */ 
640 png_byte *data; /* Data, should not be modified on read! */ 
641 size_t size
642 
643 /* On write 'location' must be set using the flag values listed below. 
644 * Notice that on read it is set by libpng however the values stored have 
645 * more bits set than are listed below. Always treat the value as a 
646 * bitmask. On write set only one bit - setting multiple bits may cause the 
647 * chunk to be written in multiple places. 
648 */ 
649 png_byte location; /* mode of operation at read time */ 
650
651png_unknown_chunk
652 
653typedef png_unknown_chunk * png_unknown_chunkp
654typedef const png_unknown_chunk * png_const_unknown_chunkp
655typedef png_unknown_chunk * * png_unknown_chunkpp
656#endif 
657 
658/* Flag values for the unknown chunk location byte. */ 
659#define PNG_HAVE_IHDR 0x01 
660#define PNG_HAVE_PLTE 0x02 
661#define PNG_AFTER_IDAT 0x08 
662 
663/* Maximum positive integer used in PNG is (2^31)-1 */ 
664#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL) 
665#define PNG_UINT_32_MAX ((png_uint_32)(-1)) 
666#define PNG_SIZE_MAX ((size_t)(-1)) 
667 
668/* These are constants for fixed point values encoded in the 
669 * PNG specification manner (x100000) 
670 */ 
671#define PNG_FP_1 100000 
672#define PNG_FP_HALF 50000 
673#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL) 
674#define PNG_FP_MIN (-PNG_FP_MAX) 
675 
676/* These describe the color_type field in png_info. */ 
677/* color type masks */ 
678#define PNG_COLOR_MASK_PALETTE 1 
679#define PNG_COLOR_MASK_COLOR 2 
680#define PNG_COLOR_MASK_ALPHA 4 
681 
682/* color types. Note that not all combinations are legal */ 
683#define PNG_COLOR_TYPE_GRAY 0 
684#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE) 
685#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR) 
686#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA) 
687#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA) 
688/* aliases */ 
689#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA 
690#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA 
691 
692/* This is for compression type. PNG 1.0-1.2 only define the single type. */ 
693#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */ 
694#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE 
695 
696/* This is for filter type. PNG 1.0-1.2 only define the single type. */ 
697#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */ 
698#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */ 
699#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE 
700 
701/* These are for the interlacing type. These values should NOT be changed. */ 
702#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */ 
703#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */ 
704#define PNG_INTERLACE_LAST 2 /* Not a valid value */ 
705 
706/* These are for the oFFs chunk. These values should NOT be changed. */ 
707#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */ 
708#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */ 
709#define PNG_OFFSET_LAST 2 /* Not a valid value */ 
710 
711/* These are for the pCAL chunk. These values should NOT be changed. */ 
712#define PNG_EQUATION_LINEAR 0 /* Linear transformation */ 
713#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */ 
714#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */ 
715#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */ 
716#define PNG_EQUATION_LAST 4 /* Not a valid value */ 
717 
718/* These are for the sCAL chunk. These values should NOT be changed. */ 
719#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */ 
720#define PNG_SCALE_METER 1 /* meters per pixel */ 
721#define PNG_SCALE_RADIAN 2 /* radians per pixel */ 
722#define PNG_SCALE_LAST 3 /* Not a valid value */ 
723 
724/* These are for the pHYs chunk. These values should NOT be changed. */ 
725#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */ 
726#define PNG_RESOLUTION_METER 1 /* pixels/meter */ 
727#define PNG_RESOLUTION_LAST 2 /* Not a valid value */ 
728 
729/* These are for the sRGB chunk. These values should NOT be changed. */ 
730#define PNG_sRGB_INTENT_PERCEPTUAL 0 
731#define PNG_sRGB_INTENT_RELATIVE 1 
732#define PNG_sRGB_INTENT_SATURATION 2 
733#define PNG_sRGB_INTENT_ABSOLUTE 3 
734#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */ 
735 
736/* This is for text chunks */ 
737#define PNG_KEYWORD_MAX_LENGTH 79 
738 
739/* Maximum number of entries in PLTE/sPLT/tRNS arrays */ 
740#define PNG_MAX_PALETTE_LENGTH 256 
741 
742/* These determine if an ancillary chunk's data has been successfully read 
743 * from the PNG header, or if the application has filled in the corresponding 
744 * data in the info_struct to be written into the output file. The values 
745 * of the PNG_INFO_<chunk> defines should NOT be changed. 
746 */ 
747#define PNG_INFO_gAMA 0x0001U 
748#define PNG_INFO_sBIT 0x0002U 
749#define PNG_INFO_cHRM 0x0004U 
750#define PNG_INFO_PLTE 0x0008U 
751#define PNG_INFO_tRNS 0x0010U 
752#define PNG_INFO_bKGD 0x0020U 
753#define PNG_INFO_hIST 0x0040U 
754#define PNG_INFO_pHYs 0x0080U 
755#define PNG_INFO_oFFs 0x0100U 
756#define PNG_INFO_tIME 0x0200U 
757#define PNG_INFO_pCAL 0x0400U 
758#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */ 
759#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */ 
760#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */ 
761#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */ 
762#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */ 
763#define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */ 
764#ifdef PNG_APNG_SUPPORTED 
765#define PNG_INFO_acTL 0x20000U 
766#define PNG_INFO_fcTL 0x40000U 
767#endif 
768 
769/* This is used for the transformation routines, as some of them 
770 * change these values for the row. It also should enable using 
771 * the routines for other purposes. 
772 */ 
773typedef struct png_row_info_struct 
774
775 png_uint_32 width; /* width of row */ 
776 size_t rowbytes; /* number of bytes in row */ 
777 png_byte color_type; /* color type of row */ 
778 png_byte bit_depth; /* bit depth of row */ 
779 png_byte channels; /* number of channels (1, 2, 3, or 4) */ 
780 png_byte pixel_depth; /* bits per pixel (depth * channels) */ 
781} png_row_info
782 
783typedef png_row_info * png_row_infop
784typedef png_row_info * * png_row_infopp
785 
786/* These are the function types for the I/O functions and for the functions 
787 * that allow the user to override the default I/O functions with his or her 
788 * own. The png_error_ptr type should match that of user-supplied warning 
789 * and error functions, while the png_rw_ptr type should match that of the 
790 * user read/write data functions. Note that the 'write' function must not 
791 * modify the buffer it is passed. The 'read' function, on the other hand, is 
792 * expected to return the read data in the buffer. 
793 */ 
794typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp)); 
795typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t)); 
796typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp)); 
797typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32
798 int)); 
799typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32
800 int)); 
801 
802#ifdef PNG_PROGRESSIVE_READ_SUPPORTED 
803typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop)); 
804typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop)); 
805#ifdef PNG_APNG_SUPPORTED 
806typedef PNG_CALLBACK(void, *png_progressive_frame_ptr, (png_structp
807 png_uint_32)); 
808#endif 
809 
810/* The following callback receives png_uint_32 row_number, int pass for the 
811 * png_bytep data of the row. When transforming an interlaced image the 
812 * row number is the row number within the sub-image of the interlace pass, so 
813 * the value will increase to the height of the sub-image (not the full image) 
814 * then reset to 0 for the next pass. 
815 * 
816 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to 
817 * find the output pixel (x,y) given an interlaced sub-image pixel 
818 * (row,col,pass). (See below for these macros.) 
819 */ 
820typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep
821 png_uint_32, int)); 
822#endif 
823 
824#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ 
825 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) 
826typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop
827 png_bytep)); 
828#endif 
829 
830#ifdef PNG_USER_CHUNKS_SUPPORTED 
831typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp
832 png_unknown_chunkp)); 
833#endif 
834#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED 
835/* not used anywhere */ 
836/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */ 
837#endif 
838 
839#ifdef PNG_SETJMP_SUPPORTED 
840/* This must match the function definition in <setjmp.h>, and the application 
841 * must include this before png.h to obtain the definition of jmp_buf. The 
842 * function is required to be PNG_NORETURN, but this is not checked. If the 
843 * function does return the application will crash via an abort() or similar 
844 * system level call. 
845 * 
846 * If you get a warning here while building the library you may need to make 
847 * changes to ensure that pnglibconf.h records the calling convention used by 
848 * your compiler. This may be very difficult - try using a different compiler 
849 * to build the library! 
850 */ 
851PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef); 
852#endif 
853 
854/* Transform masks for the high-level interface */ 
855#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */ 
856#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */ 
857#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */ 
858#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */ 
859#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */ 
860#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */ 
861#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */ 
862#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */ 
863#define PNG_TRANSFORM_BGR 0x0080 /* read and write */ 
864#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */ 
865#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */ 
866#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */ 
867#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */ 
868/* Added to libpng-1.2.34 */ 
869#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER 
870#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */ 
871/* Added to libpng-1.4.0 */ 
872#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */ 
873/* Added to libpng-1.5.4 */ 
874#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */ 
875#if INT_MAX >= 0x8000 /* else this might break */ 
876#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */ 
877#endif 
878 
879/* Flags for MNG supported features */ 
880#define PNG_FLAG_MNG_EMPTY_PLTE 0x01 
881#define PNG_FLAG_MNG_FILTER_64 0x04 
882#define PNG_ALL_MNG_FEATURES 0x05 
883 
884/* NOTE: prior to 1.5 these functions had no 'API' style declaration, 
885 * this allowed the zlib default functions to be used on Windows 
886 * platforms. In 1.5 the zlib default malloc (which just calls malloc and 
887 * ignores the first argument) should be completely compatible with the 
888 * following. 
889 */ 
890typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp
891 png_alloc_size_t)); 
892typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp)); 
893 
894/* Section 4: exported functions 
895 * Here are the function definitions most commonly used. This is not 
896 * the place to find out how to use libpng. See libpng-manual.txt for the 
897 * full explanation, see example.c for the summary. This just provides 
898 * a simple one line description of the use of each function. 
899 * 
900 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in 
901 * pngconf.h and in the *.dfn files in the scripts directory. 
902 * 
903 * PNG_EXPORT(ordinal, type, name, (args)); 
904 * 
905 * ordinal: ordinal that is used while building 
906 * *.def files. The ordinal value is only 
907 * relevant when preprocessing png.h with 
908 * the *.dfn files for building symbol table 
909 * entries, and are removed by pngconf.h. 
910 * type: return type of the function 
911 * name: function name 
912 * args: function arguments, with types 
913 * 
914 * When we wish to append attributes to a function prototype we use 
915 * the PNG_EXPORTA() macro instead. 
916 * 
917 * PNG_EXPORTA(ordinal, type, name, (args), attributes); 
918 * 
919 * ordinal, type, name, and args: same as in PNG_EXPORT(). 
920 * attributes: function attributes 
921 */ 
922 
923/* Returns the version number of the library */ 
924PNG_EXPORT(1, png_uint_32, png_access_version_number, (void)); 
925 
926/* Tell lib we have already handled the first <num_bytes> magic bytes. 
927 * Handling more than 8 bytes from the beginning of the file is an error. 
928 */ 
929PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes)); 
930 
931/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a 
932 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG 
933 * signature, and non-zero otherwise. Having num_to_check == 0 or 
934 * start > 7 will always fail (ie return non-zero). 
935 */ 
936PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start
937 size_t num_to_check)); 
938 
939/* Simple signature checking function. This is the same as calling 
940 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n). 
941 */ 
942#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n)) 
943 
944/* Allocate and initialize png_ptr struct for reading, and any other memory. */ 
945PNG_EXPORTA(4, png_structp, png_create_read_struct
946 (png_const_charp user_png_ver, png_voidp error_ptr
947 png_error_ptr error_fn, png_error_ptr warn_fn), 
948 PNG_ALLOCATED); 
949 
950/* Allocate and initialize png_ptr struct for writing, and any other memory */ 
951PNG_EXPORTA(5, png_structp, png_create_write_struct
952 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn
953 png_error_ptr warn_fn), 
954 PNG_ALLOCATED); 
955 
956PNG_EXPORT(6, size_t, png_get_compression_buffer_size
957 (png_const_structrp png_ptr)); 
958 
959PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr
960 size_t size)); 
961 
962/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp 
963 * match up. 
964 */ 
965#ifdef PNG_SETJMP_SUPPORTED 
966/* This function returns the jmp_buf built in to *png_ptr. It must be 
967 * supplied with an appropriate 'longjmp' function to use on that jmp_buf 
968 * unless the default error function is overridden in which case NULL is 
969 * acceptable. The size of the jmp_buf is checked against the actual size 
970 * allocated by the library - the call will return NULL on a mismatch 
971 * indicating an ABI mismatch. 
972 */ 
973PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr
974 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size)); 
975# define png_jmpbuf(png_ptr) \ 
976 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf)))) 
977#else 
978# define png_jmpbuf(png_ptr) \ 
979 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP) 
980#endif 
981/* This function should be used by libpng applications in place of 
982 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it 
983 * will use it; otherwise it will call PNG_ABORT(). This function was 
984 * added in libpng-1.5.0. 
985 */ 
986PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val), 
987 PNG_NORETURN); 
988 
989#ifdef PNG_READ_SUPPORTED 
990/* Reset the compression stream */ 
991PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED); 
992#endif 
993 
994/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */ 
995#ifdef PNG_USER_MEM_SUPPORTED 
996PNG_EXPORTA(11, png_structp, png_create_read_struct_2
997 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn
998 png_error_ptr warn_fn
999 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn), 
1000 PNG_ALLOCATED); 
1001PNG_EXPORTA(12, png_structp, png_create_write_struct_2
1002 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn
1003 png_error_ptr warn_fn
1004 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn), 
1005 PNG_ALLOCATED); 
1006#endif 
1007 
1008/* Write the PNG file signature. */ 
1009PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr)); 
1010 
1011/* Write a PNG chunk - size, type, (optional) data, CRC. */ 
1012PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep 
1013 chunk_name, png_const_bytep data, size_t length)); 
1014 
1015/* Write the start of a PNG chunk - length and chunk name. */ 
1016PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr
1017 png_const_bytep chunk_name, png_uint_32 length)); 
1018 
1019/* Write the data of a PNG chunk started with png_write_chunk_start(). */ 
1020PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr
1021 png_const_bytep data, size_t length)); 
1022 
1023/* Finish a chunk started with png_write_chunk_start() (includes CRC). */ 
1024PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr)); 
1025 
1026/* Allocate and initialize the info structure */ 
1027PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr), 
1028 PNG_ALLOCATED); 
1029 
1030/* DEPRECATED: this function allowed init structures to be created using the 
1031 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and 
1032 * the API will be removed in the future. 
1033 */ 
1034PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr
1035 size_t png_info_struct_size), PNG_DEPRECATED); 
1036 
1037/* Writes all the PNG information before the image. */ 
1038PNG_EXPORT(20, void, png_write_info_before_PLTE
1039 (png_structrp png_ptr, png_const_inforp info_ptr)); 
1040PNG_EXPORT(21, void, png_write_info
1041 (png_structrp png_ptr, png_const_inforp info_ptr)); 
1042 
1043#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 
1044/* Read the information before the actual image data. */ 
1045PNG_EXPORT(22, void, png_read_info
1046 (png_structrp png_ptr, png_inforp info_ptr)); 
1047#endif 
1048 
1049#ifdef PNG_TIME_RFC1123_SUPPORTED 
1050 /* Convert to a US string format: there is no localization support in this 
1051 * routine. The original implementation used a 29 character buffer in 
1052 * png_struct, this will be removed in future versions. 
1053 */ 
1054#if PNG_LIBPNG_VER < 10700 
1055/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */ 
1056PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr
1057 png_const_timep ptime),PNG_DEPRECATED); 
1058#endif 
1059PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29], 
1060 png_const_timep ptime)); 
1061#endif 
1062 
1063#ifdef PNG_CONVERT_tIME_SUPPORTED 
1064/* Convert from a struct tm to png_time */ 
1065PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime
1066 const struct tm * ttime)); 
1067 
1068/* Convert from time_t to png_time. Uses gmtime() */ 
1069PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime)); 
1070#endif /* CONVERT_tIME */ 
1071 
1072#ifdef PNG_READ_EXPAND_SUPPORTED 
1073/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */ 
1074PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr)); 
1075PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr)); 
1076PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr)); 
1077PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr)); 
1078#endif 
1079 
1080#ifdef PNG_READ_EXPAND_16_SUPPORTED 
1081/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion 
1082 * of a tRNS chunk if present. 
1083 */ 
1084PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr)); 
1085#endif 
1086 
1087#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) 
1088/* Use blue, green, red order for pixels. */ 
1089PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr)); 
1090#endif 
1091 
1092#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED 
1093/* Expand the grayscale to 24-bit RGB if necessary. */ 
1094PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr)); 
1095#endif 
1096 
1097#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED 
1098/* Reduce RGB to grayscale. */ 
1099#define PNG_ERROR_ACTION_NONE 1 
1100#define PNG_ERROR_ACTION_WARN 2 
1101#define PNG_ERROR_ACTION_ERROR 3 
1102#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/ 
1103 
1104PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr
1105 int error_action, double red, double green)) 
1106PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr
1107 int error_action, png_fixed_point red, png_fixed_point green)) 
1108 
1109PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp 
1110 png_ptr)); 
1111#endif 
1112 
1113#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED 
1114PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth
1115 png_colorp palette)); 
1116#endif 
1117 
1118#ifdef PNG_READ_ALPHA_MODE_SUPPORTED 
1119/* How the alpha channel is interpreted - this affects how the color channels 
1120 * of a PNG file are returned to the calling application when an alpha channel, 
1121 * or a tRNS chunk in a palette file, is present. 
1122 * 
1123 * This has no effect on the way pixels are written into a PNG output 
1124 * datastream. The color samples in a PNG datastream are never premultiplied 
1125 * with the alpha samples. 
1126 * 
1127 * The default is to return data according to the PNG specification: the alpha 
1128 * channel is a linear measure of the contribution of the pixel to the 
1129 * corresponding composited pixel, and the color channels are unassociated 
1130 * (not premultiplied). The gamma encoded color channels must be scaled 
1131 * according to the contribution and to do this it is necessary to undo 
1132 * the encoding, scale the color values, perform the composition and re-encode 
1133 * the values. This is the 'PNG' mode. 
1134 * 
1135 * The alternative is to 'associate' the alpha with the color information by 
1136 * storing color channel values that have been scaled by the alpha. 
1137 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes 
1138 * (the latter being the two common names for associated alpha color channels). 
1139 * 
1140 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha 
1141 * value is equal to the maximum value. 
1142 * 
1143 * The final choice is to gamma encode the alpha channel as well. This is 
1144 * broken because, in practice, no implementation that uses this choice 
1145 * correctly undoes the encoding before handling alpha composition. Use this 
1146 * choice only if other serious errors in the software or hardware you use 
1147 * mandate it; the typical serious error is for dark halos to appear around 
1148 * opaque areas of the composited PNG image because of arithmetic overflow. 
1149 * 
1150 * The API function png_set_alpha_mode specifies which of these choices to use 
1151 * with an enumerated 'mode' value and the gamma of the required output: 
1152 */ 
1153#define PNG_ALPHA_PNG 0 /* according to the PNG standard */ 
1154#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */ 
1155#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */ 
1156#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */ 
1157#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */ 
1158#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */ 
1159 
1160PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode
1161 double output_gamma)) 
1162PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr
1163 int mode, png_fixed_point output_gamma)) 
1164#endif 
1165 
1166#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED) 
1167/* The output_gamma value is a screen gamma in libpng terminology: it expresses 
1168 * how to decode the output values, not how they are encoded. 
1169 */ 
1170#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */ 
1171#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */ 
1172#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */ 
1173#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */ 
1174#endif 
1175 
1176/* The following are examples of calls to png_set_alpha_mode to achieve the 
1177 * required overall gamma correction and, where necessary, alpha 
1178 * premultiplication. 
1179 * 
1180 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); 
1181 * This is the default libpng handling of the alpha channel - it is not 
1182 * pre-multiplied into the color components. In addition the call states 
1183 * that the output is for a sRGB system and causes all PNG files without gAMA 
1184 * chunks to be assumed to be encoded using sRGB. 
1185 * 
1186 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); 
1187 * In this case the output is assumed to be something like an sRGB conformant 
1188 * display preceded by a power-law lookup table of power 1.45. This is how 
1189 * early Mac systems behaved. 
1190 * 
1191 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR); 
1192 * This is the classic Jim Blinn approach and will work in academic 
1193 * environments where everything is done by the book. It has the shortcoming 
1194 * of assuming that input PNG data with no gamma information is linear - this 
1195 * is unlikely to be correct unless the PNG files where generated locally. 
1196 * Most of the time the output precision will be so low as to show 
1197 * significant banding in dark areas of the image. 
1198 * 
1199 * png_set_expand_16(pp); 
1200 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB); 
1201 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files 
1202 * are assumed to have the sRGB encoding if not marked with a gamma value and 
1203 * the output is always 16 bits per component. This permits accurate scaling 
1204 * and processing of the data. If you know that your input PNG files were 
1205 * generated locally you might need to replace PNG_DEFAULT_sRGB with the 
1206 * correct value for your system. 
1207 * 
1208 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB); 
1209 * If you just need to composite the PNG image onto an existing background 
1210 * and if you control the code that does this you can use the optimization 
1211 * setting. In this case you just copy completely opaque pixels to the 
1212 * output. For pixels that are not completely transparent (you just skip 
1213 * those) you do the composition math using png_composite or png_composite_16 
1214 * below then encode the resultant 8-bit or 16-bit values to match the output 
1215 * encoding. 
1216 * 
1217 * Other cases 
1218 * If neither the PNG nor the standard linear encoding work for you because 
1219 * of the software or hardware you use then you have a big problem. The PNG 
1220 * case will probably result in halos around the image. The linear encoding 
1221 * will probably result in a washed out, too bright, image (it's actually too 
1222 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably 
1223 * substantially reduce the halos. Alternatively try: 
1224 * 
1225 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB); 
1226 * This option will also reduce the halos, but there will be slight dark 
1227 * halos round the opaque parts of the image where the background is light. 
1228 * In the OPTIMIZED mode the halos will be light halos where the background 
1229 * is dark. Take your pick - the halos are unavoidable unless you can get 
1230 * your hardware/software fixed! (The OPTIMIZED approach is slightly 
1231 * faster.) 
1232 * 
1233 * When the default gamma of PNG files doesn't match the output gamma. 
1234 * If you have PNG files with no gamma information png_set_alpha_mode allows 
1235 * you to provide a default gamma, but it also sets the output gamma to the 
1236 * matching value. If you know your PNG files have a gamma that doesn't 
1237 * match the output you can take advantage of the fact that 
1238 * png_set_alpha_mode always sets the output gamma but only sets the PNG 
1239 * default if it is not already set: 
1240 * 
1241 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); 
1242 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); 
1243 * The first call sets both the default and the output gamma values, the 
1244 * second call overrides the output gamma without changing the default. This 
1245 * is easier than achieving the same effect with png_set_gamma. You must use 
1246 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will 
1247 * fire if more than one call to png_set_alpha_mode and png_set_background is 
1248 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG 
1249 * are ignored. 
1250 */ 
1251 
1252#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED 
1253PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr)); 
1254#endif 
1255 
1256#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ 
1257 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) 
1258PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr)); 
1259#endif 
1260 
1261#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ 
1262 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) 
1263PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr)); 
1264#endif 
1265 
1266#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) 
1267/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */ 
1268PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler
1269 int flags)); 
1270/* The values of the PNG_FILLER_ defines should NOT be changed */ 
1271# define PNG_FILLER_BEFORE 0 
1272# define PNG_FILLER_AFTER 1 
1273/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */ 
1274PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr
1275 png_uint_32 filler, int flags)); 
1276#endif /* READ_FILLER || WRITE_FILLER */ 
1277 
1278#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) 
1279/* Swap bytes in 16-bit depth files. */ 
1280PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr)); 
1281#endif 
1282 
1283#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) 
1284/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */ 
1285PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr)); 
1286#endif 
1287 
1288#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \ 
1289 defined(PNG_WRITE_PACKSWAP_SUPPORTED) 
1290/* Swap packing order of pixels in bytes. */ 
1291PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr)); 
1292#endif 
1293 
1294#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) 
1295/* Converts files to legal bit depths. */ 
1296PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p 
1297 true_bits)); 
1298#endif 
1299 
1300#if defined(PNG_READ_INTERLACING_SUPPORTED) || \ 
1301 defined(PNG_WRITE_INTERLACING_SUPPORTED) 
1302/* Have the code handle the interlacing. Returns the number of passes. 
1303 * MUST be called before png_read_update_info or png_start_read_image, 
1304 * otherwise it will not have the desired effect. Note that it is still 
1305 * necessary to call png_read_row or png_read_rows png_get_image_height 
1306 * times for each pass. 
1307*/ 
1308PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr)); 
1309#endif 
1310 
1311#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) 
1312/* Invert monochrome files */ 
1313PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr)); 
1314#endif 
1315 
1316#ifdef PNG_READ_BACKGROUND_SUPPORTED 
1317/* Handle alpha and tRNS by replacing with a background color. Prior to 
1318 * libpng-1.5.4 this API must not be called before the PNG file header has been 
1319 * read. Doing so will result in unexpected behavior and possible warnings or 
1320 * errors if the PNG file contains a bKGD chunk. 
1321 */ 
1322PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr
1323 png_const_color_16p background_color, int background_gamma_code
1324 int need_expand, double background_gamma)) 
1325PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr
1326 png_const_color_16p background_color, int background_gamma_code
1327 int need_expand, png_fixed_point background_gamma)) 
1328#endif 
1329#ifdef PNG_READ_BACKGROUND_SUPPORTED 
1330# define PNG_BACKGROUND_GAMMA_UNKNOWN 0 
1331# define PNG_BACKGROUND_GAMMA_SCREEN 1 
1332# define PNG_BACKGROUND_GAMMA_FILE 2 
1333# define PNG_BACKGROUND_GAMMA_UNIQUE 3 
1334#endif 
1335 
1336#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED 
1337/* Scale a 16-bit depth file down to 8-bit, accurately. */ 
1338PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr)); 
1339#endif 
1340 
1341#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED 
1342#define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */ 
1343/* Strip the second byte of information from a 16-bit depth file. */ 
1344PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr)); 
1345#endif 
1346 
1347#ifdef PNG_READ_QUANTIZE_SUPPORTED 
1348/* Turn on quantizing, and reduce the palette to the number of colors 
1349 * available. 
1350 */ 
1351PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr
1352 png_colorp palette, int num_palette, int maximum_colors
1353 png_const_uint_16p histogram, int full_quantize)); 
1354#endif 
1355 
1356#ifdef PNG_READ_GAMMA_SUPPORTED 
1357/* The threshold on gamma processing is configurable but hard-wired into the 
1358 * library. The following is the floating point variant. 
1359 */ 
1360#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001) 
1361 
1362/* Handle gamma correction. Screen_gamma=(display_exponent). 
1363 * NOTE: this API simply sets the screen and file gamma values. It will 
1364 * therefore override the value for gamma in a PNG file if it is called after 
1365 * the file header has been read - use with care - call before reading the PNG 
1366 * file for best results! 
1367 * 
1368 * These routines accept the same gamma values as png_set_alpha_mode (described 
1369 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either 
1370 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value 
1371 * is the inverse of a 'screen gamma' value. 
1372 */ 
1373PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr
1374 double screen_gamma, double override_file_gamma)) 
1375PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr
1376 png_fixed_point screen_gamma, png_fixed_point override_file_gamma)) 
1377#endif 
1378 
1379#ifdef PNG_WRITE_FLUSH_SUPPORTED 
1380/* Set how many lines between output flushes - 0 for no flushing */ 
1381PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows)); 
1382/* Flush the current PNG output buffer */ 
1383PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr)); 
1384#endif 
1385 
1386/* Optional update palette with requested transformations */ 
1387PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr)); 
1388 
1389/* Optional call to update the users info structure */ 
1390PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr
1391 png_inforp info_ptr)); 
1392 
1393#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 
1394/* Read one or more rows of image data. */ 
1395PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row
1396 png_bytepp display_row, png_uint_32 num_rows)); 
1397#endif 
1398 
1399#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 
1400/* Read a row of data. */ 
1401PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row
1402 png_bytep display_row)); 
1403#endif 
1404 
1405#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 
1406/* Read the whole image into memory at once. */ 
1407PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image)); 
1408#endif 
1409 
1410/* Write a row of image data */ 
1411PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr
1412 png_const_bytep row)); 
1413 
1414/* Write a few rows of image data: (*row) is not written; however, the type 
1415 * is declared as writeable to maintain compatibility with previous versions 
1416 * of libpng and to allow the 'display_row' array from read_rows to be passed 
1417 * unchanged to write_rows. 
1418 */ 
1419PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row
1420 png_uint_32 num_rows)); 
1421 
1422/* Write the image data */ 
1423PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image)); 
1424 
1425/* Write the end of the PNG file. */ 
1426PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr
1427 png_inforp info_ptr)); 
1428 
1429#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 
1430/* Read the end of the PNG file. */ 
1431PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr)); 
1432#endif 
1433 
1434/* Free any memory associated with the png_info_struct */ 
1435PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr
1436 png_infopp info_ptr_ptr)); 
1437 
1438/* Free any memory associated with the png_struct and the png_info_structs */ 
1439PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr
1440 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr)); 
1441 
1442/* Free any memory associated with the png_struct and the png_info_structs */ 
1443PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr
1444 png_infopp info_ptr_ptr)); 
1445 
1446/* Set the libpng method of handling chunk CRC errors */ 
1447PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action
1448 int ancil_action)); 
1449 
1450/* Values for png_set_crc_action() say how to handle CRC errors in 
1451 * ancillary and critical chunks, and whether to use the data contained 
1452 * therein. Note that it is impossible to "discard" data in a critical 
1453 * chunk. For versions prior to 0.90, the action was always error/quit, 
1454 * whereas in version 0.90 and later, the action for CRC errors in ancillary 
1455 * chunks is warn/discard. These values should NOT be changed. 
1456 * 
1457 * value action:critical action:ancillary 
1458 */ 
1459#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */ 
1460#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */ 
1461#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */ 
1462#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */ 
1463#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */ 
1464#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */ 
1465 
1466#ifdef PNG_WRITE_SUPPORTED 
1467/* These functions give the user control over the scan-line filtering in 
1468 * libpng and the compression methods used by zlib. These functions are 
1469 * mainly useful for testing, as the defaults should work with most users. 
1470 * Those users who are tight on memory or want faster performance at the 
1471 * expense of compression can modify them. See the compression library 
1472 * header file (zlib.h) for an explination of the compression functions. 
1473 */ 
1474 
1475/* Set the filtering method(s) used by libpng. Currently, the only valid 
1476 * value for "method" is 0. 
1477 */ 
1478PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method
1479 int filters)); 
1480#endif /* WRITE */ 
1481 
1482/* Flags for png_set_filter() to say which filters to use. The flags 
1483 * are chosen so that they don't conflict with real filter types 
1484 * below, in case they are supplied instead of the #defined constants. 
1485 * These values should NOT be changed. 
1486 */ 
1487#define PNG_NO_FILTERS 0x00 
1488#define PNG_FILTER_NONE 0x08 
1489#define PNG_FILTER_SUB 0x10 
1490#define PNG_FILTER_UP 0x20 
1491#define PNG_FILTER_AVG 0x40 
1492#define PNG_FILTER_PAETH 0x80 
1493#define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP) 
1494#define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH) 
1495 
1496/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now. 
1497 * These defines should NOT be changed. 
1498 */ 
1499#define PNG_FILTER_VALUE_NONE 0 
1500#define PNG_FILTER_VALUE_SUB 1 
1501#define PNG_FILTER_VALUE_UP 2 
1502#define PNG_FILTER_VALUE_AVG 3 
1503#define PNG_FILTER_VALUE_PAETH 4 
1504#define PNG_FILTER_VALUE_LAST 5 
1505 
1506#ifdef PNG_WRITE_SUPPORTED 
1507#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */ 
1508PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr
1509 int heuristic_method, int num_weights, png_const_doublep filter_weights
1510 png_const_doublep filter_costs)) 
1511PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed
1512 (png_structrp png_ptr, int heuristic_method, int num_weights
1513 png_const_fixed_point_p filter_weights
1514 png_const_fixed_point_p filter_costs)) 
1515#endif /* WRITE_WEIGHTED_FILTER */ 
1516 
1517/* The following are no longer used and will be removed from libpng-1.7: */ 
1518#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */ 
1519#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */ 
1520#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */ 
1521#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */ 
1522 
1523/* Set the library compression level. Currently, valid values range from 
1524 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9 
1525 * (0 - no compression, 9 - "maximal" compression). Note that tests have 
1526 * shown that zlib compression levels 3-6 usually perform as well as level 9 
1527 * for PNG images, and do considerably fewer caclulations. In the future, 
1528 * these values may not correspond directly to the zlib compression levels. 
1529 */ 
1530#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED 
1531PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr
1532 int level)); 
1533 
1534PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr
1535 int mem_level)); 
1536 
1537PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr
1538 int strategy)); 
1539 
1540/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a 
1541 * smaller value of window_bits if it can do so safely. 
1542 */ 
1543PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr
1544 int window_bits)); 
1545 
1546PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr
1547 int method)); 
1548#endif /* WRITE_CUSTOMIZE_COMPRESSION */ 
1549 
1550#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED 
1551/* Also set zlib parameters for compressing non-IDAT chunks */ 
1552PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr
1553 int level)); 
1554 
1555PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr
1556 int mem_level)); 
1557 
1558PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr
1559 int strategy)); 
1560 
1561/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a 
1562 * smaller value of window_bits if it can do so safely. 
1563 */ 
1564PNG_EXPORT(225, void, png_set_text_compression_window_bits
1565 (png_structrp png_ptr, int window_bits)); 
1566 
1567PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr
1568 int method)); 
1569#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ 
1570#endif /* WRITE */ 
1571 
1572/* These next functions are called for input/output, memory, and error 
1573 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c, 
1574 * and call standard C I/O routines such as fread(), fwrite(), and 
1575 * fprintf(). These functions can be made to use other I/O routines 
1576 * at run time for those applications that need to handle I/O in a 
1577 * different manner by calling png_set_???_fn(). See libpng-manual.txt for 
1578 * more information. 
1579 */ 
1580 
1581#ifdef PNG_STDIO_SUPPORTED 
1582/* Initialize the input/output for the PNG file to the default functions. */ 
1583PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp)); 
1584#endif 
1585 
1586/* Replace the (error and abort), and warning functions with user 
1587 * supplied functions. If no messages are to be printed you must still 
1588 * write and use replacement functions. The replacement error_fn should 
1589 * still do a longjmp to the last setjmp location if you are using this 
1590 * method of error handling. If error_fn or warning_fn is NULL, the 
1591 * default function will be used. 
1592 */ 
1593 
1594PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr
1595 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn)); 
1596 
1597/* Return the user pointer associated with the error functions */ 
1598PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr)); 
1599 
1600/* Replace the default data output functions with a user supplied one(s). 
1601 * If buffered output is not used, then output_flush_fn can be set to NULL. 
1602 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time 
1603 * output_flush_fn will be ignored (and thus can be NULL). 
1604 * It is probably a mistake to use NULL for output_flush_fn if 
1605 * write_data_fn is not also NULL unless you have built libpng with 
1606 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's 
1607 * default flush function, which uses the standard *FILE structure, will 
1608 * be used. 
1609 */ 
1610PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr
1611 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)); 
1612 
1613/* Replace the default data input function with a user supplied one. */ 
1614PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr
1615 png_rw_ptr read_data_fn)); 
1616 
1617/* Return the user pointer associated with the I/O functions */ 
1618PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr)); 
1619 
1620PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr
1621 png_read_status_ptr read_row_fn)); 
1622 
1623PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr
1624 png_write_status_ptr write_row_fn)); 
1625 
1626#ifdef PNG_USER_MEM_SUPPORTED 
1627/* Replace the default memory allocation functions with user supplied one(s). */ 
1628PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr
1629 png_malloc_ptr malloc_fn, png_free_ptr free_fn)); 
1630/* Return the user pointer associated with the memory functions */ 
1631PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr)); 
1632#endif 
1633 
1634#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED 
1635PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr
1636 png_user_transform_ptr read_user_transform_fn)); 
1637#endif 
1638 
1639#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED 
1640PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr
1641 png_user_transform_ptr write_user_transform_fn)); 
1642#endif 
1643 
1644#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED 
1645PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr
1646 png_voidp user_transform_ptr, int user_transform_depth
1647 int user_transform_channels)); 
1648/* Return the user pointer associated with the user transform functions */ 
1649PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr
1650 (png_const_structrp png_ptr)); 
1651#endif 
1652 
1653#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED 
1654/* Return information about the row currently being processed. Note that these 
1655 * APIs do not fail but will return unexpected results if called outside a user 
1656 * transform callback. Also note that when transforming an interlaced image the 
1657 * row number is the row number within the sub-image of the interlace pass, so 
1658 * the value will increase to the height of the sub-image (not the full image) 
1659 * then reset to 0 for the next pass. 
1660 * 
1661 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to 
1662 * find the output pixel (x,y) given an interlaced sub-image pixel 
1663 * (row,col,pass). (See below for these macros.) 
1664 */ 
1665PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp)); 
1666PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp)); 
1667#endif 
1668 
1669#ifdef PNG_READ_USER_CHUNKS_SUPPORTED 
1670/* This callback is called only for *unknown* chunks. If 
1671 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known 
1672 * chunks to be treated as unknown, however in this case the callback must do 
1673 * any processing required by the chunk (e.g. by calling the appropriate 
1674 * png_set_ APIs.) 
1675 * 
1676 * There is no write support - on write, by default, all the chunks in the 
1677 * 'unknown' list are written in the specified position. 
1678 * 
1679 * The integer return from the callback function is interpreted thus: 
1680 * 
1681 * negative: An error occurred; png_chunk_error will be called. 
1682 * zero: The chunk was not handled, the chunk will be saved. A critical 
1683 * chunk will cause an error at this point unless it is to be saved. 
1684 * positive: The chunk was handled, libpng will ignore/discard it. 
1685 * 
1686 * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about 
1687 * how this behavior will change in libpng 1.7 
1688 */ 
1689PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr
1690 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn)); 
1691#endif 
1692 
1693#ifdef PNG_USER_CHUNKS_SUPPORTED 
1694PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr)); 
1695#endif 
1696 
1697#ifdef PNG_PROGRESSIVE_READ_SUPPORTED 
1698/* Sets the function callbacks for the push reader, and a pointer to a 
1699 * user-defined structure available to the callback functions. 
1700 */ 
1701PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr
1702 png_voidp progressive_ptr, png_progressive_info_ptr info_fn
1703 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn)); 
1704 
1705/* Returns the user pointer associated with the push read functions */ 
1706PNG_EXPORT(91, png_voidp, png_get_progressive_ptr
1707 (png_const_structrp png_ptr)); 
1708 
1709/* Function to be called when data becomes available */ 
1710PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr
1711 png_inforp info_ptr, png_bytep buffer, size_t buffer_size)); 
1712 
1713/* A function which may be called *only* within png_process_data to stop the 
1714 * processing of any more data. The function returns the number of bytes 
1715 * remaining, excluding any that libpng has cached internally. A subsequent 
1716 * call to png_process_data must supply these bytes again. If the argument 
1717 * 'save' is set to true the routine will first save all the pending data and 
1718 * will always return 0. 
1719 */ 
1720PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save)); 
1721 
1722/* A function which may be called *only* outside (after) a call to 
1723 * png_process_data. It returns the number of bytes of data to skip in the 
1724 * input. Normally it will return 0, but if it returns a non-zero value the 
1725 * application must skip than number of bytes of input data and pass the 
1726 * following data to the next call to png_process_data. 
1727 */ 
1728PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp)); 
1729 
1730/* Function that combines rows. 'new_row' is a flag that should come from 
1731 * the callback and be non-NULL if anything needs to be done; the library 
1732 * stores its own version of the new data internally and ignores the passed 
1733 * in value. 
1734 */ 
1735PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr
1736 png_bytep old_row, png_const_bytep new_row)); 
1737#endif /* PROGRESSIVE_READ */ 
1738 
1739PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr
1740 png_alloc_size_t size), PNG_ALLOCATED); 
1741/* Added at libpng version 1.4.0 */ 
1742PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr
1743 png_alloc_size_t size), PNG_ALLOCATED); 
1744 
1745/* Added at libpng version 1.2.4 */ 
1746PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr
1747 png_alloc_size_t size), PNG_ALLOCATED); 
1748 
1749/* Frees a pointer allocated by png_malloc() */ 
1750PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr)); 
1751 
1752/* Free data that was allocated internally */ 
1753PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr
1754 png_inforp info_ptr, png_uint_32 free_me, int num)); 
1755 
1756/* Reassign responsibility for freeing existing data, whether allocated 
1757 * by libpng or by the application; this works on the png_info structure passed 
1758 * in, it does not change the state for other png_info structures. 
1759 * 
1760 * It is unlikely that this function works correctly as of 1.6.0 and using it 
1761 * may result either in memory leaks or double free of allocated data. 
1762 */ 
1763PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr
1764 png_inforp info_ptr, int freer, png_uint_32 mask)); 
1765 
1766/* Assignments for png_data_freer */ 
1767#define PNG_DESTROY_WILL_FREE_DATA 1 
1768#define PNG_SET_WILL_FREE_DATA 1 
1769#define PNG_USER_WILL_FREE_DATA 2 
1770/* Flags for png_ptr->free_me and info_ptr->free_me */ 
1771#define PNG_FREE_HIST 0x0008U 
1772#define PNG_FREE_ICCP 0x0010U 
1773#define PNG_FREE_SPLT 0x0020U 
1774#define PNG_FREE_ROWS 0x0040U 
1775#define PNG_FREE_PCAL 0x0080U 
1776#define PNG_FREE_SCAL 0x0100U 
1777#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 
1778# define PNG_FREE_UNKN 0x0200U 
1779#endif 
1780/* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */ 
1781#define PNG_FREE_PLTE 0x1000U 
1782#define PNG_FREE_TRNS 0x2000U 
1783#define PNG_FREE_TEXT 0x4000U 
1784#define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */ 
1785#define PNG_FREE_ALL 0xffffU 
1786#define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */ 
1787 
1788#ifdef PNG_USER_MEM_SUPPORTED 
1789PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr
1790 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED); 
1791PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr
1792 png_voidp ptr), PNG_DEPRECATED); 
1793#endif 
1794 
1795#ifdef PNG_ERROR_TEXT_SUPPORTED 
1796/* Fatal error in PNG image of libpng - can't continue */ 
1797PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr
1798 png_const_charp error_message), PNG_NORETURN); 
1799 
1800/* The same, but the chunk name is prepended to the error string. */ 
1801PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr
1802 png_const_charp error_message), PNG_NORETURN); 
1803 
1804#else 
1805/* Fatal error in PNG image of libpng - can't continue */ 
1806PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN); 
1807# define png_error(s1,s2) png_err(s1) 
1808# define png_chunk_error(s1,s2) png_err(s1) 
1809#endif 
1810 
1811#ifdef PNG_WARNINGS_SUPPORTED 
1812/* Non-fatal error in libpng. Can continue, but may have a problem. */ 
1813PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr
1814 png_const_charp warning_message)); 
1815 
1816/* Non-fatal error in libpng, chunk name is prepended to message. */ 
1817PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr
1818 png_const_charp warning_message)); 
1819#else 
1820# define png_warning(s1,s2) ((void)(s1)) 
1821# define png_chunk_warning(s1,s2) ((void)(s1)) 
1822#endif 
1823 
1824#ifdef PNG_BENIGN_ERRORS_SUPPORTED 
1825/* Benign error in libpng. Can continue, but may have a problem. 
1826 * User can choose whether to handle as a fatal error or as a warning. */ 
1827PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr
1828 png_const_charp warning_message)); 
1829 
1830#ifdef PNG_READ_SUPPORTED 
1831/* Same, chunk name is prepended to message (only during read) */ 
1832PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr
1833 png_const_charp warning_message)); 
1834#endif 
1835 
1836PNG_EXPORT(109, void, png_set_benign_errors
1837 (png_structrp png_ptr, int allowed)); 
1838#else 
1839# ifdef PNG_ALLOW_BENIGN_ERRORS 
1840# define png_benign_error png_warning 
1841# define png_chunk_benign_error png_chunk_warning 
1842# else 
1843# define png_benign_error png_error 
1844# define png_chunk_benign_error png_chunk_error 
1845# endif 
1846#endif 
1847 
1848/* The png_set_<chunk> functions are for storing values in the png_info_struct. 
1849 * Similarly, the png_get_<chunk> calls are used to read values from the 
1850 * png_info_struct, either storing the parameters in the passed variables, or 
1851 * setting pointers into the png_info_struct where the data is stored. The 
1852 * png_get_<chunk> functions return a non-zero value if the data was available 
1853 * in info_ptr, or return zero and do not change any of the parameters if the 
1854 * data was not available. 
1855 * 
1856 * These functions should be used instead of directly accessing png_info 
1857 * to avoid problems with future changes in the size and internal layout of 
1858 * png_info_struct. 
1859 */ 
1860/* Returns "flag" if chunk data is valid in info_ptr. */ 
1861PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr
1862 png_const_inforp info_ptr, png_uint_32 flag)); 
1863 
1864/* Returns number of bytes needed to hold a transformed row. */ 
1865PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr
1866 png_const_inforp info_ptr)); 
1867 
1868#ifdef PNG_INFO_IMAGE_SUPPORTED 
1869/* Returns row_pointers, which is an array of pointers to scanlines that was 
1870 * returned from png_read_png(). 
1871 */ 
1872PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr
1873 png_const_inforp info_ptr)); 
1874 
1875/* Set row_pointers, which is an array of pointers to scanlines for use 
1876 * by png_write_png(). 
1877 */ 
1878PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr
1879 png_inforp info_ptr, png_bytepp row_pointers)); 
1880#endif 
1881 
1882/* Returns number of color channels in image. */ 
1883PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr
1884 png_const_inforp info_ptr)); 
1885 
1886#ifdef PNG_EASY_ACCESS_SUPPORTED 
1887/* Returns image width in pixels. */ 
1888PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr
1889 png_const_inforp info_ptr)); 
1890 
1891/* Returns image height in pixels. */ 
1892PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr
1893 png_const_inforp info_ptr)); 
1894 
1895/* Returns image bit_depth. */ 
1896PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr
1897 png_const_inforp info_ptr)); 
1898 
1899/* Returns image color_type. */ 
1900PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr
1901 png_const_inforp info_ptr)); 
1902 
1903/* Returns image filter_type. */ 
1904PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr
1905 png_const_inforp info_ptr)); 
1906 
1907/* Returns image interlace_type. */ 
1908PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr
1909 png_const_inforp info_ptr)); 
1910 
1911/* Returns image compression_type. */ 
1912PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr
1913 png_const_inforp info_ptr)); 
1914 
1915/* Returns image resolution in pixels per meter, from pHYs chunk data. */ 
1916PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter
1917 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1918PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter
1919 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1920PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter
1921 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1922 
1923/* Returns pixel aspect ratio, computed from pHYs chunk data. */ 
1924PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio
1925 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 
1926PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed
1927 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 
1928 
1929/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */ 
1930PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels
1931 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1932PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels
1933 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1934PNG_EXPORT(128, png_int_32, png_get_x_offset_microns
1935 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1936PNG_EXPORT(129, png_int_32, png_get_y_offset_microns
1937 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
1938 
1939#endif /* EASY_ACCESS */ 
1940 
1941#ifdef PNG_READ_SUPPORTED 
1942/* Returns pointer to signature string read from PNG header */ 
1943PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr
1944 png_const_inforp info_ptr)); 
1945#endif 
1946 
1947#ifdef PNG_bKGD_SUPPORTED 
1948PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr
1949 png_inforp info_ptr, png_color_16p *background)); 
1950#endif 
1951 
1952#ifdef PNG_bKGD_SUPPORTED 
1953PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr
1954 png_inforp info_ptr, png_const_color_16p background)); 
1955#endif 
1956 
1957#ifdef PNG_cHRM_SUPPORTED 
1958PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr
1959 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x
1960 double *red_y, double *green_x, double *green_y, double *blue_x
1961 double *blue_y)) 
1962PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr
1963 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z
1964 double *green_X, double *green_Y, double *green_Z, double *blue_X
1965 double *blue_Y, double *blue_Z)) 
1966PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed
1967 (png_const_structrp png_ptr, png_const_inforp info_ptr
1968 png_fixed_point *int_white_x, png_fixed_point *int_white_y
1969 png_fixed_point *int_red_x, png_fixed_point *int_red_y
1970 png_fixed_point *int_green_x, png_fixed_point *int_green_y
1971 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y)) 
1972PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed
1973 (png_const_structrp png_ptr, png_const_inforp info_ptr
1974 png_fixed_point *int_red_X, png_fixed_point *int_red_Y
1975 png_fixed_point *int_red_Z, png_fixed_point *int_green_X
1976 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z
1977 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y
1978 png_fixed_point *int_blue_Z)) 
1979#endif 
1980 
1981#ifdef PNG_cHRM_SUPPORTED 
1982PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr
1983 png_inforp info_ptr
1984 double white_x, double white_y, double red_x, double red_y, double green_x
1985 double green_y, double blue_x, double blue_y)) 
1986PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr
1987 png_inforp info_ptr, double red_X, double red_Y, double red_Z
1988 double green_X, double green_Y, double green_Z, double blue_X
1989 double blue_Y, double blue_Z)) 
1990PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr
1991 png_inforp info_ptr, png_fixed_point int_white_x
1992 png_fixed_point int_white_y, png_fixed_point int_red_x
1993 png_fixed_point int_red_y, png_fixed_point int_green_x
1994 png_fixed_point int_green_y, png_fixed_point int_blue_x
1995 png_fixed_point int_blue_y)) 
1996PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr
1997 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y
1998 png_fixed_point int_red_Z, png_fixed_point int_green_X
1999 png_fixed_point int_green_Y, png_fixed_point int_green_Z
2000 png_fixed_point int_blue_X, png_fixed_point int_blue_Y
2001 png_fixed_point int_blue_Z)) 
2002#endif 
2003 
2004#ifdef PNG_eXIf_SUPPORTED 
2005PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr
2006 png_inforp info_ptr, png_bytep *exif)); 
2007PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr
2008 png_inforp info_ptr, png_bytep exif)); 
2009 
2010PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr
2011 png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif)); 
2012PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr
2013 png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif)); 
2014#endif 
2015 
2016#ifdef PNG_gAMA_SUPPORTED 
2017PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr
2018 png_const_inforp info_ptr, double *file_gamma)) 
2019PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed
2020 (png_const_structrp png_ptr, png_const_inforp info_ptr
2021 png_fixed_point *int_file_gamma)) 
2022#endif 
2023 
2024#ifdef PNG_gAMA_SUPPORTED 
2025PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr
2026 png_inforp info_ptr, double file_gamma)) 
2027PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr
2028 png_inforp info_ptr, png_fixed_point int_file_gamma)) 
2029#endif 
2030 
2031#ifdef PNG_hIST_SUPPORTED 
2032PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr
2033 png_inforp info_ptr, png_uint_16p *hist)); 
2034PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr
2035 png_inforp info_ptr, png_const_uint_16p hist)); 
2036#endif 
2037 
2038PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr
2039 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height
2040 int *bit_depth, int *color_type, int *interlace_method
2041 int *compression_method, int *filter_method)); 
2042 
2043PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr
2044 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth
2045 int color_type, int interlace_method, int compression_method
2046 int filter_method)); 
2047 
2048#ifdef PNG_oFFs_SUPPORTED 
2049PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr
2050 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y
2051 int *unit_type)); 
2052#endif 
2053 
2054#ifdef PNG_oFFs_SUPPORTED 
2055PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr
2056 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y
2057 int unit_type)); 
2058#endif 
2059 
2060#ifdef PNG_pCAL_SUPPORTED 
2061PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr
2062 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0
2063 png_int_32 *X1, int *type, int *nparams, png_charp *units
2064 png_charpp *params)); 
2065#endif 
2066 
2067#ifdef PNG_pCAL_SUPPORTED 
2068PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr
2069 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1
2070 int type, int nparams, png_const_charp units, png_charpp params)); 
2071#endif 
2072 
2073#ifdef PNG_pHYs_SUPPORTED 
2074PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr
2075 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y
2076 int *unit_type)); 
2077#endif 
2078 
2079#ifdef PNG_pHYs_SUPPORTED 
2080PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr
2081 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type)); 
2082#endif 
2083 
2084PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr
2085 png_inforp info_ptr, png_colorp *palette, int *num_palette)); 
2086 
2087PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr
2088 png_inforp info_ptr, png_const_colorp palette, int num_palette)); 
2089 
2090#ifdef PNG_sBIT_SUPPORTED 
2091PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr
2092 png_inforp info_ptr, png_color_8p *sig_bit)); 
2093#endif 
2094 
2095#ifdef PNG_sBIT_SUPPORTED 
2096PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr
2097 png_inforp info_ptr, png_const_color_8p sig_bit)); 
2098#endif 
2099 
2100#ifdef PNG_sRGB_SUPPORTED 
2101PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr
2102 png_const_inforp info_ptr, int *file_srgb_intent)); 
2103#endif 
2104 
2105#ifdef PNG_sRGB_SUPPORTED 
2106PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr
2107 png_inforp info_ptr, int srgb_intent)); 
2108PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr
2109 png_inforp info_ptr, int srgb_intent)); 
2110#endif 
2111 
2112#ifdef PNG_iCCP_SUPPORTED 
2113PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr
2114 png_inforp info_ptr, png_charpp name, int *compression_type
2115 png_bytepp profile, png_uint_32 *proflen)); 
2116#endif 
2117 
2118#ifdef PNG_iCCP_SUPPORTED 
2119PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr
2120 png_inforp info_ptr, png_const_charp name, int compression_type
2121 png_const_bytep profile, png_uint_32 proflen)); 
2122#endif 
2123 
2124#ifdef PNG_sPLT_SUPPORTED 
2125PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr
2126 png_inforp info_ptr, png_sPLT_tpp entries)); 
2127#endif 
2128 
2129#ifdef PNG_sPLT_SUPPORTED 
2130PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr
2131 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)); 
2132#endif 
2133 
2134#ifdef PNG_TEXT_SUPPORTED 
2135/* png_get_text also returns the number of text chunks in *num_text */ 
2136PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr
2137 png_inforp info_ptr, png_textp *text_ptr, int *num_text)); 
2138#endif 
2139 
2140/* Note while png_set_text() will accept a structure whose text, 
2141 * language, and translated keywords are NULL pointers, the structure 
2142 * returned by png_get_text will always contain regular 
2143 * zero-terminated C strings. They might be empty strings but 
2144 * they will never be NULL pointers. 
2145 */ 
2146 
2147#ifdef PNG_TEXT_SUPPORTED 
2148PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr
2149 png_inforp info_ptr, png_const_textp text_ptr, int num_text)); 
2150#endif 
2151 
2152#ifdef PNG_tIME_SUPPORTED 
2153PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr
2154 png_inforp info_ptr, png_timep *mod_time)); 
2155#endif 
2156 
2157#ifdef PNG_tIME_SUPPORTED 
2158PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr
2159 png_inforp info_ptr, png_const_timep mod_time)); 
2160#endif 
2161 
2162#ifdef PNG_tRNS_SUPPORTED 
2163PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr
2164 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans
2165 png_color_16p *trans_color)); 
2166#endif 
2167 
2168#ifdef PNG_tRNS_SUPPORTED 
2169PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr
2170 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans
2171 png_const_color_16p trans_color)); 
2172#endif 
2173 
2174#ifdef PNG_sCAL_SUPPORTED 
2175PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr
2176 png_const_inforp info_ptr, int *unit, double *width, double *height)) 
2177#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \ 
2178 defined(PNG_FLOATING_POINT_SUPPORTED) 
2179/* NOTE: this API is currently implemented using floating point arithmetic, 
2180 * consequently it can only be used on systems with floating point support. 
2181 * In any case the range of values supported by png_fixed_point is small and it 
2182 * is highly recommended that png_get_sCAL_s be used instead. 
2183 */ 
2184PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed
2185 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit
2186 png_fixed_point *width, png_fixed_point *height)) 
2187#endif 
2188PNG_EXPORT(169, png_uint_32, png_get_sCAL_s
2189 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit
2190 png_charpp swidth, png_charpp sheight)); 
2191 
2192PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr
2193 png_inforp info_ptr, int unit, double width, double height)) 
2194PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr
2195 png_inforp info_ptr, int unit, png_fixed_point width
2196 png_fixed_point height)) 
2197PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr
2198 png_inforp info_ptr, int unit
2199 png_const_charp swidth, png_const_charp sheight)); 
2200#endif /* sCAL */ 
2201 
2202#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED 
2203/* Provide the default handling for all unknown chunks or, optionally, for 
2204 * specific unknown chunks. 
2205 * 
2206 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was 
2207 * ignored and the default was used, the per-chunk setting only had an effect on 
2208 * write. If you wish to have chunk-specific handling on read in code that must 
2209 * work on earlier versions you must use a user chunk callback to specify the 
2210 * desired handling (keep or discard.) 
2211 * 
2212 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The 
2213 * parameter is interpreted as follows: 
2214 * 
2215 * READ: 
2216 * PNG_HANDLE_CHUNK_AS_DEFAULT: 
2217 * Known chunks: do normal libpng processing, do not keep the chunk (but 
2218 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED) 
2219 * Unknown chunks: for a specific chunk use the global default, when used 
2220 * as the default discard the chunk data. 
2221 * PNG_HANDLE_CHUNK_NEVER: 
2222 * Discard the chunk data. 
2223 * PNG_HANDLE_CHUNK_IF_SAFE: 
2224 * Keep the chunk data if the chunk is not critical else raise a chunk 
2225 * error. 
2226 * PNG_HANDLE_CHUNK_ALWAYS: 
2227 * Keep the chunk data. 
2228 * 
2229 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks, 
2230 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent 
2231 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks 
2232 * it simply resets the behavior to the libpng default. 
2233 * 
2234 * INTERACTION WITH USER CHUNK CALLBACKS: 
2235 * The per-chunk handling is always used when there is a png_user_chunk_ptr 
2236 * callback and the callback returns 0; the chunk is then always stored *unless* 
2237 * it is critical and the per-chunk setting is other than ALWAYS. Notice that 
2238 * the global default is *not* used in this case. (In effect the per-chunk 
2239 * value is incremented to at least IF_SAFE.) 
2240 * 
2241 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and 
2242 * per-chunk defaults will be honored. If you want to preserve the current 
2243 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE 
2244 * as the default - if you don't do this libpng 1.6 will issue a warning. 
2245 * 
2246 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and 
2247 * earlier simply return '1' (handled). 
2248 * 
2249 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED: 
2250 * If this is *not* set known chunks will always be handled by libpng and 
2251 * will never be stored in the unknown chunk list. Known chunks listed to 
2252 * png_set_keep_unknown_chunks will have no effect. If it is set then known 
2253 * chunks listed with a keep other than AS_DEFAULT will *never* be processed 
2254 * by libpng, in addition critical chunks must either be processed by the 
2255 * callback or saved. 
2256 * 
2257 * The IHDR and IEND chunks must not be listed. Because this turns off the 
2258 * default handling for chunks that would otherwise be recognized the 
2259 * behavior of libpng transformations may well become incorrect! 
2260 * 
2261 * WRITE: 
2262 * When writing chunks the options only apply to the chunks specified by 
2263 * png_set_unknown_chunks (below), libpng will *always* write known chunks 
2264 * required by png_set_ calls and will always write the core critical chunks 
2265 * (as required for PLTE). 
2266 * 
2267 * Each chunk in the png_set_unknown_chunks list is looked up in the 
2268 * png_set_keep_unknown_chunks list to find the keep setting, this is then 
2269 * interpreted as follows: 
2270 * 
2271 * PNG_HANDLE_CHUNK_AS_DEFAULT: 
2272 * Write safe-to-copy chunks and write other chunks if the global 
2273 * default is set to _ALWAYS, otherwise don't write this chunk. 
2274 * PNG_HANDLE_CHUNK_NEVER: 
2275 * Do not write the chunk. 
2276 * PNG_HANDLE_CHUNK_IF_SAFE: 
2277 * Write the chunk if it is safe-to-copy, otherwise do not write it. 
2278 * PNG_HANDLE_CHUNK_ALWAYS: 
2279 * Write the chunk. 
2280 * 
2281 * Note that the default behavior is effectively the opposite of the read case - 
2282 * in read unknown chunks are not stored by default, in write they are written 
2283 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different 
2284 * - on write the safe-to-copy bit is checked, on read the critical bit is 
2285 * checked and on read if the chunk is critical an error will be raised. 
2286 * 
2287 * num_chunks: 
2288 * =========== 
2289 * If num_chunks is positive, then the "keep" parameter specifies the manner 
2290 * for handling only those chunks appearing in the chunk_list array, 
2291 * otherwise the chunk list array is ignored. 
2292 * 
2293 * If num_chunks is 0 the "keep" parameter specifies the default behavior for 
2294 * unknown chunks, as described above. 
2295 * 
2296 * If num_chunks is negative, then the "keep" parameter specifies the manner 
2297 * for handling all unknown chunks plus all chunks recognized by libpng 
2298 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to 
2299 * be processed by libpng. 
2300 */ 
2301#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED 
2302PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr
2303 int keep, png_const_bytep chunk_list, int num_chunks)); 
2304#endif /* HANDLE_AS_UNKNOWN */ 
2305 
2306/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned; 
2307 * the result is therefore true (non-zero) if special handling is required, 
2308 * false for the default handling. 
2309 */ 
2310PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr
2311 png_const_bytep chunk_name)); 
2312#endif /* SET_UNKNOWN_CHUNKS */ 
2313 
2314#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED 
2315PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr
2316 png_inforp info_ptr, png_const_unknown_chunkp unknowns
2317 int num_unknowns)); 
2318 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added 
2319 * unknowns to the location currently stored in the png_struct. This is 
2320 * invariably the wrong value on write. To fix this call the following API 
2321 * for each chunk in the list with the correct location. If you know your 
2322 * code won't be compiled on earlier versions you can rely on 
2323 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing 
2324 * the correct thing. 
2325 */ 
2326 
2327PNG_EXPORT(175, void, png_set_unknown_chunk_location
2328 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location)); 
2329 
2330PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr
2331 png_inforp info_ptr, png_unknown_chunkpp entries)); 
2332#endif 
2333 
2334/* Png_free_data() will turn off the "valid" flag for anything it frees. 
2335 * If you need to turn it off for a chunk that your application has freed, 
2336 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); 
2337 */ 
2338PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr
2339 png_inforp info_ptr, int mask)); 
2340 
2341#ifdef PNG_INFO_IMAGE_SUPPORTED 
2342/* The "params" pointer is currently not used and is for future expansion. */ 
2343#ifdef PNG_SEQUENTIAL_READ_SUPPORTED 
2344PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr
2345 int transforms, png_voidp params)); 
2346#endif 
2347#ifdef PNG_WRITE_SUPPORTED 
2348PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr
2349 int transforms, png_voidp params)); 
2350#endif 
2351#endif 
2352 
2353PNG_EXPORT(180, png_const_charp, png_get_copyright
2354 (png_const_structrp png_ptr)); 
2355PNG_EXPORT(181, png_const_charp, png_get_header_ver
2356 (png_const_structrp png_ptr)); 
2357PNG_EXPORT(182, png_const_charp, png_get_header_version
2358 (png_const_structrp png_ptr)); 
2359PNG_EXPORT(183, png_const_charp, png_get_libpng_ver
2360 (png_const_structrp png_ptr)); 
2361 
2362#ifdef PNG_MNG_FEATURES_SUPPORTED 
2363PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr
2364 png_uint_32 mng_features_permitted)); 
2365#endif 
2366 
2367/* For use in png_set_keep_unknown, added to version 1.2.6 */ 
2368#define PNG_HANDLE_CHUNK_AS_DEFAULT 0 
2369#define PNG_HANDLE_CHUNK_NEVER 1 
2370#define PNG_HANDLE_CHUNK_IF_SAFE 2 
2371#define PNG_HANDLE_CHUNK_ALWAYS 3 
2372#define PNG_HANDLE_CHUNK_LAST 4 
2373 
2374/* Strip the prepended error numbers ("#nnn ") from error and warning 
2375 * messages before passing them to the error or warning handler. 
2376 */ 
2377#ifdef PNG_ERROR_NUMBERS_SUPPORTED 
2378PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr, 
2379 png_uint_32 strip_mode)); 
2380#endif 
2381 
2382/* Added in libpng-1.2.6 */ 
2383#ifdef PNG_SET_USER_LIMITS_SUPPORTED 
2384PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr
2385 png_uint_32 user_width_max, png_uint_32 user_height_max)); 
2386PNG_EXPORT(187, png_uint_32, png_get_user_width_max
2387 (png_const_structrp png_ptr)); 
2388PNG_EXPORT(188, png_uint_32, png_get_user_height_max
2389 (png_const_structrp png_ptr)); 
2390/* Added in libpng-1.4.0 */ 
2391PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr
2392 png_uint_32 user_chunk_cache_max)); 
2393PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max
2394 (png_const_structrp png_ptr)); 
2395/* Added in libpng-1.4.1 */ 
2396PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr
2397 png_alloc_size_t user_chunk_cache_max)); 
2398PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max
2399 (png_const_structrp png_ptr)); 
2400#endif 
2401 
2402#if defined(PNG_INCH_CONVERSIONS_SUPPORTED) 
2403PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch
2404 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
2405 
2406PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch
2407 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
2408 
2409PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch
2410 (png_const_structrp png_ptr, png_const_inforp info_ptr)); 
2411 
2412PNG_FP_EXPORT(196, float, png_get_x_offset_inches
2413 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 
2414#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ 
2415PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed
2416 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 
2417#endif 
2418 
2419PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr
2420 png_const_inforp info_ptr)) 
2421#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ 
2422PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed
2423 (png_const_structrp png_ptr, png_const_inforp info_ptr)) 
2424#endif 
2425 
2426# ifdef PNG_pHYs_SUPPORTED 
2427PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr
2428 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y
2429 int *unit_type)); 
2430# endif /* pHYs */ 
2431#endif /* INCH_CONVERSIONS */ 
2432 
2433/* Added in libpng-1.4.0 */ 
2434#ifdef PNG_IO_STATE_SUPPORTED 
2435PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr)); 
2436 
2437/* Removed from libpng 1.6; use png_get_io_chunk_type. */ 
2438PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr), 
2439 PNG_DEPRECATED) 
2440 
2441PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type
2442 (png_const_structrp png_ptr)); 
2443 
2444/* The flags returned by png_get_io_state() are the following: */ 
2445# define PNG_IO_NONE 0x0000 /* no I/O at this moment */ 
2446# define PNG_IO_READING 0x0001 /* currently reading */ 
2447# define PNG_IO_WRITING 0x0002 /* currently writing */ 
2448# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */ 
2449# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */ 
2450# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */ 
2451# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */ 
2452# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */ 
2453# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */ 
2454#endif /* IO_STATE */ 
2455 
2456/* Interlace support. The following macros are always defined so that if 
2457 * libpng interlace handling is turned off the macros may be used to handle 
2458 * interlaced images within the application. 
2459 */ 
2460#define PNG_INTERLACE_ADAM7_PASSES 7 
2461 
2462/* Two macros to return the first row and first column of the original, 
2463 * full, image which appears in a given pass. 'pass' is in the range 0 
2464 * to 6 and the result is in the range 0 to 7. 
2465 */ 
2466#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7) 
2467#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7) 
2468 
2469/* A macro to return the offset between pixels in the output row for a pair of 
2470 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that 
2471 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas 
2472 * COL_OFFSET is from one column to the next, within a row. 
2473 */ 
2474#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8) 
2475#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1)) 
2476 
2477/* Two macros to help evaluate the number of rows or columns in each 
2478 * pass. This is expressed as a shift - effectively log2 of the number or 
2479 * rows or columns in each 8x8 tile of the original image. 
2480 */ 
2481#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3) 
2482#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3) 
2483 
2484/* Hence two macros to determine the number of rows or columns in a given 
2485 * pass of an image given its height or width. In fact these macros may 
2486 * return non-zero even though the sub-image is empty, because the other 
2487 * dimension may be empty for a small image. 
2488 */ 
2489#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\ 
2490 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass)) 
2491#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\ 
2492 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass)) 
2493 
2494/* For the reader row callbacks (both progressive and sequential) it is 
2495 * necessary to find the row in the output image given a row in an interlaced 
2496 * image, so two more macros: 
2497 */ 
2498#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \ 
2499 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass)) 
2500#define PNG_COL_FROM_PASS_COL(x_in, pass) \ 
2501 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass)) 
2502 
2503/* Two macros which return a boolean (0 or 1) saying whether the given row 
2504 * or column is in a particular pass. These use a common utility macro that 
2505 * returns a mask for a given pass - the offset 'off' selects the row or 
2506 * column version. The mask has the appropriate bit set for each column in 
2507 * the tile. 
2508 */ 
2509#define PNG_PASS_MASK(pass,off) ( \ 
2510 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \ 
2511 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0)) 
2512 
2513#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \ 
2514 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1) 
2515#define PNG_COL_IN_INTERLACE_PASS(x, pass) \ 
2516 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1) 
2517 
2518#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED 
2519/* With these routines we avoid an integer divide, which will be slower on 
2520 * most machines. However, it does take more operations than the corresponding 
2521 * divide method, so it may be slower on a few RISC systems. There are two 
2522 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide. 
2523 * 
2524 * Note that the rounding factors are NOT supposed to be the same! 128 and 
2525 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the 
2526 * standard method. 
2527 * 
2528 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ] 
2529 */ 
2530 
2531 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */ 
2532 
2533# define png_composite(composite, fg, alpha, bg) \ 
2534 { \ 
2535 png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \ 
2536 * (png_uint_16)(alpha) \ 
2537 + (png_uint_16)(bg)*(png_uint_16)(255 \ 
2538 - (png_uint_16)(alpha)) + 128); \ 
2539 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \ 
2540 } 
2541 
2542# define png_composite_16(composite, fg, alpha, bg) \ 
2543 { \ 
2544 png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \ 
2545 * (png_uint_32)(alpha) \ 
2546 + (png_uint_32)(bg)*(65535 \ 
2547 - (png_uint_32)(alpha)) + 32768); \ 
2548 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \ 
2549 } 
2550 
2551#else /* Standard method using integer division */ 
2552 
2553# define png_composite(composite, fg, alpha, bg) \ 
2554 (composite) = \ 
2555 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \ 
2556 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \ 
2557 127) / 255)) 
2558 
2559# define png_composite_16(composite, fg, alpha, bg) \ 
2560 (composite) = \ 
2561 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \ 
2562 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \ 
2563 32767) / 65535)) 
2564#endif /* READ_COMPOSITE_NODIV */ 
2565 
2566#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED 
2567PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf)); 
2568PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf)); 
2569PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf)); 
2570#endif 
2571 
2572PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr
2573 png_const_bytep buf)); 
2574/* No png_get_int_16 -- may be added if there's a real need for it. */ 
2575 
2576/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */ 
2577#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED 
2578PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i)); 
2579#endif 
2580#ifdef PNG_SAVE_INT_32_SUPPORTED 
2581PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i)); 
2582#endif 
2583 
2584/* Place a 16-bit number into a buffer in PNG byte order. 
2585 * The parameter is declared unsigned int, not png_uint_16, 
2586 * just to avoid potential problems on pre-ANSI C compilers. 
2587 */ 
2588#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED 
2589PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i)); 
2590/* No png_save_int_16 -- may be added if there's a real need for it. */ 
2591#endif 
2592 
2593#ifdef PNG_USE_READ_MACROS 
2594/* Inline macros to do direct reads of bytes from the input buffer. 
2595 * The png_get_int_32() routine assumes we are using two's complement 
2596 * format for negative values, which is almost certainly true. 
2597 */ 
2598# define PNG_get_uint_32(buf) \ 
2599 (((png_uint_32)(*(buf)) << 24) + \ 
2600 ((png_uint_32)(*((buf) + 1)) << 16) + \ 
2601 ((png_uint_32)(*((buf) + 2)) << 8) + \ 
2602 ((png_uint_32)(*((buf) + 3)))) 
2603 
2604 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the 
2605 * function) incorrectly returned a value of type png_uint_32. 
2606 */ 
2607# define PNG_get_uint_16(buf) \ 
2608 ((png_uint_16) \ 
2609 (((unsigned int)(*(buf)) << 8) + \ 
2610 ((unsigned int)(*((buf) + 1))))) 
2611 
2612# define PNG_get_int_32(buf) \ 
2613 ((png_int_32)((*(buf) & 0x80) \ 
2614 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \ 
2615 : (png_int_32)png_get_uint_32(buf))) 
2616 
2617/* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h, 
2618 * but defining a macro name prefixed with PNG_PREFIX. 
2619 */ 
2620# ifndef PNG_PREFIX 
2621# define png_get_uint_32(buf) PNG_get_uint_32(buf) 
2622# define png_get_uint_16(buf) PNG_get_uint_16(buf) 
2623# define png_get_int_32(buf) PNG_get_int_32(buf) 
2624# endif 
2625#else 
2626# ifdef PNG_PREFIX 
2627 /* No macros; revert to the (redefined) function */ 
2628# define PNG_get_uint_32 (png_get_uint_32) 
2629# define PNG_get_uint_16 (png_get_uint_16) 
2630# define PNG_get_int_32 (png_get_int_32) 
2631# endif 
2632#endif 
2633 
2634#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED 
2635PNG_EXPORT(242, void, png_set_check_for_invalid_index
2636 (png_structrp png_ptr, int allowed)); 
2637# ifdef PNG_GET_PALETTE_MAX_SUPPORTED 
2638PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr
2639 png_const_infop info_ptr)); 
2640# endif 
2641#endif /* CHECK_FOR_INVALID_INDEX */ 
2642 
2643/******************************************************************************* 
2644 * Section 5: SIMPLIFIED API 
2645 ******************************************************************************* 
2646 * 
2647 * Please read the documentation in libpng-manual.txt (TODO: write said 
2648 * documentation) if you don't understand what follows. 
2649 * 
2650 * The simplified API hides the details of both libpng and the PNG file format 
2651 * itself. It allows PNG files to be read into a very limited number of 
2652 * in-memory bitmap formats or to be written from the same formats. If these 
2653 * formats do not accommodate your needs then you can, and should, use the more 
2654 * sophisticated APIs above - these support a wide variety of in-memory formats 
2655 * and a wide variety of sophisticated transformations to those formats as well 
2656 * as a wide variety of APIs to manipulate ancillary information. 
2657 * 
2658 * To read a PNG file using the simplified API: 
2659 * 
2660 * 1) Declare a 'png_image' structure (see below) on the stack, set the 
2661 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL 
2662 * (this is REQUIRED, your program may crash if you don't do it.) 
2663 * 2) Call the appropriate png_image_begin_read... function. 
2664 * 3) Set the png_image 'format' member to the required sample format. 
2665 * 4) Allocate a buffer for the image and, if required, the color-map. 
2666 * 5) Call png_image_finish_read to read the image and, if required, the 
2667 * color-map into your buffers. 
2668 * 
2669 * There are no restrictions on the format of the PNG input itself; all valid 
2670 * color types, bit depths, and interlace methods are acceptable, and the 
2671 * input image is transformed as necessary to the requested in-memory format 
2672 * during the png_image_finish_read() step. The only caveat is that if you 
2673 * request a color-mapped image from a PNG that is full-color or makes 
2674 * complex use of an alpha channel the transformation is extremely lossy and the 
2675 * result may look terrible. 
2676 * 
2677 * To write a PNG file using the simplified API: 
2678 * 
2679 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero. 
2680 * 2) Initialize the members of the structure that describe the image, setting 
2681 * the 'format' member to the format of the image samples. 
2682 * 3) Call the appropriate png_image_write... function with a pointer to the 
2683 * image and, if necessary, the color-map to write the PNG data. 
2684 * 
2685 * png_image is a structure that describes the in-memory format of an image 
2686 * when it is being read or defines the in-memory format of an image that you 
2687 * need to write: 
2688 */ 
2689#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \ 
2690 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) 
2691 
2692#define PNG_IMAGE_VERSION 1 
2693 
2694typedef struct png_control *png_controlp
2695typedef struct 
2696
2697 png_controlp opaque; /* Initialize to NULL, free with png_image_free */ 
2698 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */ 
2699 png_uint_32 width; /* Image width in pixels (columns) */ 
2700 png_uint_32 height; /* Image height in pixels (rows) */ 
2701 png_uint_32 format; /* Image format as defined below */ 
2702 png_uint_32 flags; /* A bit mask containing informational flags */ 
2703 png_uint_32 colormap_entries
2704 /* Number of entries in the color-map */ 
2705 
2706 /* In the event of an error or warning the following field will be set to a 
2707 * non-zero value and the 'message' field will contain a '\0' terminated 
2708 * string with the libpng error or warning message. If both warnings and 
2709 * an error were encountered, only the error is recorded. If there 
2710 * are multiple warnings, only the first one is recorded. 
2711 * 
2712 * The upper 30 bits of this value are reserved, the low two bits contain 
2713 * a value as follows: 
2714 */ 
2715# define PNG_IMAGE_WARNING 1 
2716# define PNG_IMAGE_ERROR 2 
2717 /* 
2718 * The result is a two-bit code such that a value more than 1 indicates 
2719 * a failure in the API just called: 
2720 * 
2721 * 0 - no warning or error 
2722 * 1 - warning 
2723 * 2 - error 
2724 * 3 - error preceded by warning 
2725 */ 
2726# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1) 
2727 
2728 png_uint_32 warning_or_error
2729 
2730 char message[64]; 
2731} png_image, *png_imagep
2732 
2733/* The samples of the image have one to four channels whose components have 
2734 * original values in the range 0 to 1.0: 
2735 * 
2736 * 1: A single gray or luminance channel (G). 
2737 * 2: A gray/luminance channel and an alpha channel (GA). 
2738 * 3: Three red, green, blue color channels (RGB). 
2739 * 4: Three color channels and an alpha channel (RGBA). 
2740 * 
2741 * The components are encoded in one of two ways: 
2742 * 
2743 * a) As a small integer, value 0..255, contained in a single byte. For the 
2744 * alpha channel the original value is simply value/255. For the color or 
2745 * luminance channels the value is encoded according to the sRGB specification 
2746 * and matches the 8-bit format expected by typical display devices. 
2747 * 
2748 * The color/gray channels are not scaled (pre-multiplied) by the alpha 
2749 * channel and are suitable for passing to color management software. 
2750 * 
2751 * b) As a value in the range 0..65535, contained in a 2-byte integer. All 
2752 * channels can be converted to the original value by dividing by 65535; all 
2753 * channels are linear. Color channels use the RGB encoding (RGB end-points) of 
2754 * the sRGB specification. This encoding is identified by the 
2755 * PNG_FORMAT_FLAG_LINEAR flag below. 
2756 * 
2757 * When the simplified API needs to convert between sRGB and linear colorspaces, 
2758 * the actual sRGB transfer curve defined in the sRGB specification (see the 
2759 * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2 
2760 * approximation used elsewhere in libpng. 
2761 * 
2762 * When an alpha channel is present it is expected to denote pixel coverage 
2763 * of the color or luminance channels and is returned as an associated alpha 
2764 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha 
2765 * value. 
2766 * 
2767 * The samples are either contained directly in the image data, between 1 and 8 
2768 * bytes per pixel according to the encoding, or are held in a color-map indexed 
2769 * by bytes in the image data. In the case of a color-map the color-map entries 
2770 * are individual samples, encoded as above, and the image data has one byte per 
2771 * pixel to select the relevant sample from the color-map. 
2772 */ 
2773 
2774/* PNG_FORMAT_* 
2775 * 
2776 * #defines to be used in png_image::format. Each #define identifies a 
2777 * particular layout of sample data and, if present, alpha values. There are 
2778 * separate defines for each of the two component encodings. 
2779 * 
2780 * A format is built up using single bit flag values. All combinations are 
2781 * valid. Formats can be built up from the flag values or you can use one of 
2782 * the predefined values below. When testing formats always use the FORMAT_FLAG 
2783 * macros to test for individual features - future versions of the library may 
2784 * add new flags. 
2785 * 
2786 * When reading or writing color-mapped images the format should be set to the 
2787 * format of the entries in the color-map then png_image_{read,write}_colormap 
2788 * called to read or write the color-map and set the format correctly for the 
2789 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly! 
2790 * 
2791 * NOTE: libpng can be built with particular features disabled. If you see 
2792 * compiler errors because the definition of one of the following flags has been 
2793 * compiled out it is because libpng does not have the required support. It is 
2794 * possible, however, for the libpng configuration to enable the format on just 
2795 * read or just write; in that case you may see an error at run time. You can 
2796 * guard against this by checking for the definition of the appropriate 
2797 * "_SUPPORTED" macro, one of: 
2798 * 
2799 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED 
2800 */ 
2801#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */ 
2802#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */ 
2803#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */ 
2804#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */ 
2805 
2806#ifdef PNG_FORMAT_BGR_SUPPORTED 
2807# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */ 
2808#endif 
2809 
2810#ifdef PNG_FORMAT_AFIRST_SUPPORTED 
2811# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */ 
2812#endif 
2813 
2814#define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */ 
2815 
2816/* Commonly used formats have predefined macros. 
2817 * 
2818 * First the single byte (sRGB) formats: 
2819 */ 
2820#define PNG_FORMAT_GRAY 0 
2821#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA 
2822#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST) 
2823#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR 
2824#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR) 
2825#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA) 
2826#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST) 
2827#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA) 
2828#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST) 
2829 
2830/* Then the linear 2-byte formats. When naming these "Y" is used to 
2831 * indicate a luminance (gray) channel. 
2832 */ 
2833#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR 
2834#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA) 
2835#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR) 
2836#define PNG_FORMAT_LINEAR_RGB_ALPHA \ 
2837 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA) 
2838 
2839/* With color-mapped formats the image data is one byte for each pixel, the byte 
2840 * is an index into the color-map which is formatted as above. To obtain a 
2841 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP 
2842 * to one of the above definitions, or you can use one of the definitions below. 
2843 */ 
2844#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP) 
2845#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP) 
2846#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP) 
2847#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP) 
2848#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP) 
2849#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP) 
2850 
2851/* PNG_IMAGE macros 
2852 * 
2853 * These are convenience macros to derive information from a png_image 
2854 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the 
2855 * actual image sample values - either the entries in the color-map or the 
2856 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values 
2857 * for the pixels and will always return 1 for color-mapped formats. The 
2858 * remaining macros return information about the rows in the image and the 
2859 * complete image. 
2860 * 
2861 * NOTE: All the macros that take a png_image::format parameter are compile time 
2862 * constants if the format parameter is, itself, a constant. Therefore these 
2863 * macros can be used in array declarations and case labels where required. 
2864 * Similarly the macros are also pre-processor constants (sizeof is not used) so 
2865 * they can be used in #if tests. 
2866 * 
2867 * First the information about the samples. 
2868 */ 
2869#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\ 
2870 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1) 
2871 /* Return the total number of channels in a given format: 1..4 */ 
2872 
2873#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\ 
2874 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1) 
2875 /* Return the size in bytes of a single component of a pixel or color-map 
2876 * entry (as appropriate) in the image: 1 or 2. 
2877 */ 
2878 
2879#define PNG_IMAGE_SAMPLE_SIZE(fmt)\ 
2880 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)) 
2881 /* This is the size of the sample data for one sample. If the image is 
2882 * color-mapped it is the size of one color-map entry (and image pixels are 
2883 * one byte in size), otherwise it is the size of one image pixel. 
2884 */ 
2885 
2886#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\ 
2887 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256) 
2888 /* The maximum size of the color-map required by the format expressed in a 
2889 * count of components. This can be used to compile-time allocate a 
2890 * color-map: 
2891 * 
2892 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)]; 
2893 * 
2894 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)]; 
2895 * 
2896 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the 
2897 * information from one of the png_image_begin_read_ APIs and dynamically 
2898 * allocate the required memory. 
2899 */ 
2900 
2901/* Corresponding information about the pixels */ 
2902#define PNG_IMAGE_PIXEL_(test,fmt)\ 
2903 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt)) 
2904 
2905#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\ 
2906 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt) 
2907 /* The number of separate channels (components) in a pixel; 1 for a 
2908 * color-mapped image. 
2909 */ 
2910 
2911#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\ 
2912 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt) 
2913 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped 
2914 * image. 
2915 */ 
2916 
2917#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt) 
2918 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */ 
2919 
2920/* Information about the whole row, or whole image */ 
2921#define PNG_IMAGE_ROW_STRIDE(image)\ 
2922 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width) 
2923 /* Return the total number of components in a single row of the image; this 
2924 * is the minimum 'row stride', the minimum count of components between each 
2925 * row. For a color-mapped image this is the minimum number of bytes in a 
2926 * row. 
2927 * 
2928 * WARNING: this macro overflows for some images with more than one component 
2929 * and very large image widths. libpng will refuse to process an image where 
2930 * this macro would overflow. 
2931 */ 
2932 
2933#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\ 
2934 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride)) 
2935 /* Return the size, in bytes, of an image buffer given a png_image and a row 
2936 * stride - the number of components to leave space for in each row. 
2937 * 
2938 * WARNING: this macro overflows a 32-bit integer for some large PNG images, 
2939 * libpng will refuse to process an image where such an overflow would occur. 
2940 */ 
2941 
2942#define PNG_IMAGE_SIZE(image)\ 
2943 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image)) 
2944 /* Return the size, in bytes, of the image in memory given just a png_image; 
2945 * the row stride is the minimum stride required for the image. 
2946 */ 
2947 
2948#define PNG_IMAGE_COLORMAP_SIZE(image)\ 
2949 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries) 
2950 /* Return the size, in bytes, of the color-map of this image. If the image 
2951 * format is not a color-map format this will return a size sufficient for 
2952 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if 
2953 * you don't want to allocate a color-map in this case. 
2954 */ 
2955 
2956/* PNG_IMAGE_FLAG_* 
2957 * 
2958 * Flags containing additional information about the image are held in the 
2959 * 'flags' field of png_image. 
2960 */ 
2961#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01 
2962 /* This indicates that the RGB values of the in-memory bitmap do not 
2963 * correspond to the red, green and blue end-points defined by sRGB. 
2964 */ 
2965 
2966#define PNG_IMAGE_FLAG_FAST 0x02 
2967 /* On write emphasise speed over compression; the resultant PNG file will be 
2968 * larger but will be produced significantly faster, particular for large 
2969 * images. Do not use this option for images which will be distributed, only 
2970 * used it when producing intermediate files that will be read back in 
2971 * repeatedly. For a typical 24-bit image the option will double the read 
2972 * speed at the cost of increasing the image size by 25%, however for many 
2973 * more compressible images the PNG file can be 10 times larger with only a 
2974 * slight speed gain. 
2975 */ 
2976 
2977#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04 
2978 /* On read if the image is a 16-bit per component image and there is no gAMA 
2979 * or sRGB chunk assume that the components are sRGB encoded. Notice that 
2980 * images output by the simplified API always have gamma information; setting 
2981 * this flag only affects the interpretation of 16-bit images from an 
2982 * external source. It is recommended that the application expose this flag 
2983 * to the user; the user can normally easily recognize the difference between 
2984 * linear and sRGB encoding. This flag has no effect on write - the data 
2985 * passed to the write APIs must have the correct encoding (as defined 
2986 * above.) 
2987 * 
2988 * If the flag is not set (the default) input 16-bit per component data is 
2989 * assumed to be linear. 
2990 * 
2991 * NOTE: the flag can only be set after the png_image_begin_read_ call, 
2992 * because that call initializes the 'flags' field. 
2993 */ 
2994 
2995#ifdef PNG_SIMPLIFIED_READ_SUPPORTED 
2996/* READ APIs 
2997 * --------- 
2998 * 
2999 * The png_image passed to the read APIs must have been initialized by setting 
3000 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.) 
3001 */ 
3002#ifdef PNG_STDIO_SUPPORTED 
3003PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image
3004 const char *file_name)); 
3005 /* The named file is opened for read and the image header is filled in 
3006 * from the PNG header in the file. 
3007 */ 
3008 
3009PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image
3010 FILE* file)); 
3011 /* The PNG header is read from the stdio FILE object. */ 
3012#endif /* STDIO */ 
3013 
3014PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image
3015 png_const_voidp memory, size_t size)); 
3016 /* The PNG header is read from the given memory buffer. */ 
3017 
3018PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image
3019 png_const_colorp background, void *buffer, png_int_32 row_stride
3020 void *colormap)); 
3021 /* Finish reading the image into the supplied buffer and clean up the 
3022 * png_image structure. 
3023 * 
3024 * row_stride is the step, in byte or 2-byte units as appropriate, 
3025 * between adjacent rows. A positive stride indicates that the top-most row 
3026 * is first in the buffer - the normal top-down arrangement. A negative 
3027 * stride indicates that the bottom-most row is first in the buffer. 
3028 * 
3029 * background need only be supplied if an alpha channel must be removed from 
3030 * a png_byte format and the removal is to be done by compositing on a solid 
3031 * color; otherwise it may be NULL and any composition will be done directly 
3032 * onto the buffer. The value is an sRGB color to use for the background, 
3033 * for grayscale output the green channel is used. 
3034 * 
3035 * background must be supplied when an alpha channel must be removed from a 
3036 * single byte color-mapped output format, in other words if: 
3037 * 
3038 * 1) The original format from png_image_begin_read_from_* had 
3039 * PNG_FORMAT_FLAG_ALPHA set. 
3040 * 2) The format set by the application does not. 
3041 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and 
3042 * PNG_FORMAT_FLAG_LINEAR *not* set. 
3043 * 
3044 * For linear output removing the alpha channel is always done by compositing 
3045 * on black and background is ignored. 
3046 * 
3047 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must 
3048 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE. 
3049 * image->colormap_entries will be updated to the actual number of entries 
3050 * written to the colormap; this may be less than the original value. 
3051 */ 
3052 
3053PNG_EXPORT(238, void, png_image_free, (png_imagep image)); 
3054 /* Free any data allocated by libpng in image->opaque, setting the pointer to 
3055 * NULL. May be called at any time after the structure is initialized. 
3056 */ 
3057#endif /* SIMPLIFIED_READ */ 
3058 
3059#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED 
3060/* WRITE APIS 
3061 * ---------- 
3062 * For write you must initialize a png_image structure to describe the image to 
3063 * be written. To do this use memset to set the whole structure to 0 then 
3064 * initialize fields describing your image. 
3065 * 
3066 * version: must be set to PNG_IMAGE_VERSION 
3067 * opaque: must be initialized to NULL 
3068 * width: image width in pixels 
3069 * height: image height in rows 
3070 * format: the format of the data (image and color-map) you wish to write 
3071 * flags: set to 0 unless one of the defined flags applies; set 
3072 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB 
3073 * values do not correspond to the colors in sRGB. 
3074 * colormap_entries: set to the number of entries in the color-map (0 to 256) 
3075 */ 
3076#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED 
3077PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image
3078 const char *file, int convert_to_8bit, const void *buffer
3079 png_int_32 row_stride, const void *colormap)); 
3080 /* Write the image to the named file. */ 
3081 
3082PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file
3083 int convert_to_8_bit, const void *buffer, png_int_32 row_stride
3084 const void *colormap)); 
3085 /* Write the image to the given (FILE*). */ 
3086#endif /* SIMPLIFIED_WRITE_STDIO */ 
3087 
3088/* With all write APIs if image is in one of the linear formats with 16-bit 
3089 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG 
3090 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear 
3091 * encoded PNG file is written. 
3092 * 
3093 * With color-mapped data formats the colormap parameter point to a color-map 
3094 * with at least image->colormap_entries encoded in the specified format. If 
3095 * the format is linear the written PNG color-map will be converted to sRGB 
3096 * regardless of the convert_to_8_bit flag. 
3097 * 
3098 * With all APIs row_stride is handled as in the read APIs - it is the spacing 
3099 * from one row to the next in component sized units (1 or 2 bytes) and if 
3100 * negative indicates a bottom-up row layout in the buffer. If row_stride is 
3101 * zero, libpng will calculate it for you from the image width and number of 
3102 * channels. 
3103 * 
3104 * Note that the write API does not support interlacing, sub-8-bit pixels or 
3105 * most ancillary chunks. If you need to write text chunks (e.g. for copyright 
3106 * notices) you need to use one of the other APIs. 
3107 */ 
3108 
3109PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory
3110 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit
3111 const void *buffer, png_int_32 row_stride, const void *colormap)); 
3112 /* Write the image to the given memory buffer. The function both writes the 
3113 * whole PNG data stream to *memory and updates *memory_bytes with the count 
3114 * of bytes written. 
3115 * 
3116 * 'memory' may be NULL. In this case *memory_bytes is not read however on 
3117 * success the number of bytes which would have been written will still be 
3118 * stored in *memory_bytes. On failure *memory_bytes will contain 0. 
3119 * 
3120 * If 'memory' is not NULL it must point to memory[*memory_bytes] of 
3121 * writeable memory. 
3122 * 
3123 * If the function returns success memory[*memory_bytes] (if 'memory' is not 
3124 * NULL) contains the written PNG data. *memory_bytes will always be less 
3125 * than or equal to the original value. 
3126 * 
3127 * If the function returns false and *memory_bytes was not changed an error 
3128 * occurred during write. If *memory_bytes was changed, or is not 0 if 
3129 * 'memory' was NULL, the write would have succeeded but for the memory 
3130 * buffer being too small. *memory_bytes contains the required number of 
3131 * bytes and will be bigger that the original value. 
3132 */ 
3133 
3134#define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\ 
3135 row_stride, colormap)\ 
3136 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\ 
3137 row_stride, colormap) 
3138 /* Return the amount of memory in 'size' required to compress this image. 
3139 * The png_image structure 'image' must be filled in as in the above 
3140 * function and must not be changed before the actual write call, the buffer 
3141 * and all other parameters must also be identical to that in the final 
3142 * write call. The 'size' variable need not be initialized. 
3143 * 
3144 * NOTE: the macro returns true/false, if false is returned 'size' will be 
3145 * set to zero and the write failed and probably will fail if tried again. 
3146 */ 
3147 
3148/* You can pre-allocate the buffer by making sure it is of sufficient size 
3149 * regardless of the amount of compression achieved. The buffer size will 
3150 * always be bigger than the original image and it will never be filled. The 
3151 * following macros are provided to assist in allocating the buffer. 
3152 */ 
3153#define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height) 
3154 /* The number of uncompressed bytes in the PNG byte encoding of the image; 
3155 * uncompressing the PNG IDAT data will give this number of bytes. 
3156 * 
3157 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this 
3158 * macro can because of the extra bytes used in the PNG byte encoding. You 
3159 * need to avoid this macro if your image size approaches 2^30 in width or 
3160 * height. The same goes for the remainder of these macros; they all produce 
3161 * bigger numbers than the actual in-memory image size. 
3162 */ 
3163#ifndef PNG_ZLIB_MAX_SIZE 
3164# define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U) 
3165 /* An upper bound on the number of compressed bytes given 'b' uncompressed 
3166 * bytes. This is based on deflateBounds() in zlib; different 
3167 * implementations of zlib compression may conceivably produce more data so 
3168 * if your zlib implementation is not zlib itself redefine this macro 
3169 * appropriately. 
3170 */ 
3171#endif 
3172 
3173#define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\ 
3174 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image)) 
3175 /* An upper bound on the size of the data in the PNG IDAT chunks. */ 
3176 
3177#define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\ 
3178 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\ 
3179 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\ 
3180 12U+3U*(image).colormap_entries/*PLTE data*/+\ 
3181 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\ 
3182 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\ 
3183 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size)) 
3184 /* A helper for the following macro; if your compiler cannot handle the 
3185 * following macro use this one with the result of 
3186 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most 
3187 * compilers should handle this just fine.) 
3188 */ 
3189 
3190#define PNG_IMAGE_PNG_SIZE_MAX(image)\ 
3191 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image)) 
3192 /* An upper bound on the total length of the PNG data stream for 'image'. 
3193 * The result is of type png_alloc_size_t, on 32-bit systems this may 
3194 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will 
3195 * run out of buffer space but return a corrected size which should work. 
3196 */ 
3197#endif /* SIMPLIFIED_WRITE */ 
3198/******************************************************************************* 
3199 * END OF SIMPLIFIED API 
3200 ******************************************************************************/ 
3201#endif /* SIMPLIFIED_{READ|WRITE} */ 
3202 
3203/******************************************************************************* 
3204 * Section 6: IMPLEMENTATION OPTIONS 
3205 ******************************************************************************* 
3206 * 
3207 * Support for arbitrary implementation-specific optimizations. The API allows 
3208 * particular options to be turned on or off. 'Option' is the number of the 
3209 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given 
3210 * by the PNG_OPTION_ defines below. 
3211 * 
3212 * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions, 
3213 * are detected at run time, however sometimes it may be impossible 
3214 * to do this in user mode, in which case it is necessary to discover 
3215 * the capabilities in an OS specific way. Such capabilities are 
3216 * listed here when libpng has support for them and must be turned 
3217 * ON by the application if present. 
3218 * 
3219 * SOFTWARE: sometimes software optimizations actually result in performance 
3220 * decrease on some architectures or systems, or with some sets of 
3221 * PNG images. 'Software' options allow such optimizations to be 
3222 * selected at run time. 
3223 */ 
3224#ifdef PNG_SET_OPTION_SUPPORTED 
3225#ifdef PNG_ARM_NEON_API_SUPPORTED 
3226# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */ 
3227#endif 
3228#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */ 
3229#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */ 
3230#ifdef PNG_MIPS_MSA_API_SUPPORTED 
3231# define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */ 
3232#endif 
3233#define PNG_IGNORE_ADLER32 8 
3234#ifdef PNG_POWERPC_VSX_API_SUPPORTED 
3235# define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions supported */ 
3236#endif 
3237#define PNG_OPTION_NEXT 12 /* Next option - numbers must be even */ 
3238 
3239/* Return values: NOTE: there are four values and 'off' is *not* zero */ 
3240#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */ 
3241#define PNG_OPTION_INVALID 1 /* Option number out of range */ 
3242#define PNG_OPTION_OFF 2 
3243#define PNG_OPTION_ON 3 
3244 
3245PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option
3246 int onoff)); 
3247#endif /* SET_OPTION */ 
3248 
3249/******************************************************************************* 
3250 * END OF HARDWARE AND SOFTWARE OPTIONS 
3251 ******************************************************************************/ 
3252#ifdef PNG_APNG_SUPPORTED 
3253PNG_EXPORT(250, png_uint_32, png_get_acTL, (png_structp png_ptr
3254 png_infop info_ptr, png_uint_32 *num_frames, png_uint_32 *num_plays)); 
3255 
3256PNG_EXPORT(251, png_uint_32, png_set_acTL, (png_structp png_ptr
3257 png_infop info_ptr, png_uint_32 num_frames, png_uint_32 num_plays)); 
3258 
3259PNG_EXPORT(252, png_uint_32, png_get_num_frames, (png_structp png_ptr
3260 png_infop info_ptr)); 
3261 
3262PNG_EXPORT(253, png_uint_32, png_get_num_plays, (png_structp png_ptr
3263 png_infop info_ptr)); 
3264 
3265PNG_EXPORT(254, png_uint_32, png_get_next_frame_fcTL
3266 (png_structp png_ptr, png_infop info_ptr, png_uint_32 *width
3267 png_uint_32 *height, png_uint_32 *x_offset, png_uint_32 *y_offset
3268 png_uint_16 *delay_num, png_uint_16 *delay_den, png_byte *dispose_op
3269 png_byte *blend_op)); 
3270 
3271PNG_EXPORT(255, png_uint_32, png_set_next_frame_fcTL
3272 (png_structp png_ptr, png_infop info_ptr, png_uint_32 width
3273 png_uint_32 height, png_uint_32 x_offset, png_uint_32 y_offset
3274 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op
3275 png_byte blend_op)); 
3276 
3277PNG_EXPORT(256, png_uint_32, png_get_next_frame_width
3278 (png_structp png_ptr, png_infop info_ptr)); 
3279PNG_EXPORT(257, png_uint_32, png_get_next_frame_height
3280 (png_structp png_ptr, png_infop info_ptr)); 
3281PNG_EXPORT(258, png_uint_32, png_get_next_frame_x_offset
3282 (png_structp png_ptr, png_infop info_ptr)); 
3283PNG_EXPORT(259, png_uint_32, png_get_next_frame_y_offset
3284 (png_structp png_ptr, png_infop info_ptr)); 
3285PNG_EXPORT(260, png_uint_16, png_get_next_frame_delay_num
3286 (png_structp png_ptr, png_infop info_ptr)); 
3287PNG_EXPORT(261, png_uint_16, png_get_next_frame_delay_den
3288 (png_structp png_ptr, png_infop info_ptr)); 
3289PNG_EXPORT(262, png_byte, png_get_next_frame_dispose_op
3290 (png_structp png_ptr, png_infop info_ptr)); 
3291PNG_EXPORT(263, png_byte, png_get_next_frame_blend_op
3292 (png_structp png_ptr, png_infop info_ptr)); 
3293PNG_EXPORT(264, png_byte, png_get_first_frame_is_hidden
3294 (png_structp png_ptr, png_infop info_ptr)); 
3295PNG_EXPORT(265, png_uint_32, png_set_first_frame_is_hidden
3296 (png_structp png_ptr, png_infop info_ptr, png_byte is_hidden)); 
3297 
3298#ifdef PNG_READ_APNG_SUPPORTED 
3299PNG_EXPORT(266, void, png_read_frame_head, (png_structp png_ptr
3300 png_infop info_ptr)); 
3301#ifdef PNG_PROGRESSIVE_READ_SUPPORTED 
3302PNG_EXPORT(267, void, png_set_progressive_frame_fn, (png_structp png_ptr
3303 png_progressive_frame_ptr frame_info_fn
3304 png_progressive_frame_ptr frame_end_fn)); 
3305#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ 
3306#endif /* PNG_READ_APNG_SUPPORTED */ 
3307 
3308#ifdef PNG_WRITE_APNG_SUPPORTED 
3309PNG_EXPORT(268, void, png_write_frame_head, (png_structp png_ptr
3310 png_infop info_ptr, png_bytepp row_pointers
3311 png_uint_32 width, png_uint_32 height
3312 png_uint_32 x_offset, png_uint_32 y_offset
3313 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op
3314 png_byte blend_op)); 
3315 
3316PNG_EXPORT(269, void, png_write_frame_tail, (png_structp png_ptr
3317 png_infop info_ptr)); 
3318#endif /* PNG_WRITE_APNG_SUPPORTED */ 
3319#endif /* PNG_APNG_SUPPORTED */ 
3320 
3321/* Maintainer: Put new public prototypes here ^, in libpng.3, in project 
3322 * defs, and in scripts/symbols.def. 
3323 */ 
3324 
3325/* The last ordinal number (this is the *last* one already used; the next 
3326 * one to use is one more than this.) 
3327 */ 
3328#ifdef PNG_EXPORT_LAST_ORDINAL 
3329#ifdef PNG_APNG_SUPPORTED 
3330 PNG_EXPORT_LAST_ORDINAL(269); 
3331#else 
3332 PNG_EXPORT_LAST_ORDINAL(249); 
3333#endif /* PNG_APNG_SUPPORTED */ 
3334#endif 
3335 
3336#ifdef __cplusplus 
3337
3338#endif 
3339 
3340#endif /* PNG_VERSION_INFO_ONLY */ 
3341/* Do not put anything past this line */ 
3342#endif /* PNG_H */ 
3343