2 /* png.h - header file for PNG reference library
4 * libpng version 1.6.39 - November 20, 2022
6 * Copyright (c) 2018-2022 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.
11 * This code is released under the libpng license. (See LICENSE, below.)
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 1.6.39, November 2022:
20 * See also "Contributing Authors", below.
24 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
25 * =========================================
27 * PNG Reference Library License version 2
28 * ---------------------------------------
30 * * Copyright (c) 1995-2022 The PNG Reference Library Authors.
31 * * Copyright (c) 2018-2022 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.
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
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:
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.
55 * 2. Altered source versions must be plainly marked as such, and must
56 * not be misrepresented as being the original software.
58 * 3. This Copyright notice may not be removed or altered from any
59 * source or altered source distribution.
62 * PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
63 * -----------------------------------------------------------------------
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:
71 * Simon-Pierre Cadieux
77 * Mandar Sahastrabuddhe
81 * and with the following additions to the disclaimer:
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
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.
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:
101 * Glenn Randers-Pehrson
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:
117 * Some files in the "scripts" directory have other copyright owners,
118 * but are released under this license.
120 * libpng versions 0.5, May 1995, through 0.88, January 1996, are
121 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
123 * For the purposes of this copyright and license, "Contributing Authors"
124 * is defined as the following set of individuals:
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.
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:
145 * 1. The origin of this source code must not be misrepresented.
147 * 2. Altered versions must be plainly marked as such and must not
148 * be misrepresented as being the original source.
150 * 3. This Copyright notice may not be removed or altered from any
151 * source or altered source distribution.
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
159 * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
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.
172 * A "png_get_copyright" function is available, for convenient use in "about"
173 * boxes and the like:
175 * printf("%s", png_get_copyright(NULL));
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).
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.
186 * Thanks to Frank J. T. Wojcik for helping with the documentation.
189 /* Note about libpng version numbers:
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:
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.
219 * 1.0.5 (+ 2 patches) 10005
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)
226 * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
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)
234 * 1.0.69 10 10069 10.so.0.69[.0]
236 * 1.2.59 13 10259 12.so.0.59[.0]
238 * 1.4.20 14 10420 14.so.0.20[.0]
240 * 1.5.30 15 10530 15.so.15.30[.0]
242 * 1.6.39 16 10639 16.so.16.39[.0]
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".
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.
258 * DLLNUM will change each time there are forward or backward changes
259 * in binary compatibility (e.g., when a new feature is added).
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/>
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>
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'.
280 /* Version information for png.h - this should match the version in png.c */
281 #define PNG_LIBPNG_VER_STRING "1.6.39"
282 #define PNG_HEADER_VERSION_STRING " libpng version 1.6.39 - November 20, 2022\n"
284 #define PNG_LIBPNG_VER_SONUM 16
285 #define PNG_LIBPNG_VER_DLLNUM 16
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 39
292 /* This should be zero for a public release, or non-zero for a
293 * development version. [Deprecated]
295 #define PNG_LIBPNG_VER_BUILD 0
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
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 */
312 #define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
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
321 #define PNG_LIBPNG_VER 10639 /* 1.6.39 */
323 /* Library configuration: these options cannot be changed after
324 * the library has been built.
327 /* If pnglibconf.h is missing, you can
328 * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
330 # include "pnglibconf.h"
333 #define PNG_APNG_SUPPORTED
334 #define PNG_READ_APNG_SUPPORTED
335 #define PNG_WRITE_APNG_SUPPORTED
337 #ifndef PNG_VERSION_INFO_ONLY
338 /* Machine specific configuration. */
339 # include "pngconf.h"
343 * Added at libpng-1.2.8
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.
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.
356 #ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
357 # define PNG_LIBPNG_BUILD_TYPE \
358 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
360 # ifdef PNG_LIBPNG_SPECIALBUILD
361 # define PNG_LIBPNG_BUILD_TYPE \
362 (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
364 # define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
368 #ifndef PNG_VERSION_INFO_ONLY
370 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
373 #endif /* __cplusplus */
375 /* Version information for C files, stored in png.c. This had better match
378 #define png_libpng_ver png_get_header_ver(NULL)
380 /* This file is arranged in several sections:
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
387 * 4. Exported library functions.
389 * 6. Implementation options.
391 * The library source code has additional files (principally pngpriv.h) that
392 * allow configuration of the library.
395 /* Section 1: [omitted] */
397 /* Section 2: run time configuration
398 * See pnglibconf.h for build time configuration
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
408 * Use macros to read integers from PNG data or use the exported
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.
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'
418 * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
420 * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
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.
427 /* Section 3: type definitions, including structures and compile time
429 * See pngconf.h for base types that vary by machine/system
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
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 */
443 /* This triggers a compiler error in png.c, if png.c and png.h
444 * do not agree upon the version number.
446 typedef char* png_libpng_version_1_6_39;
448 /* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
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.
454 typedef struct png_struct_def png_struct;
455 typedef const png_struct * png_const_structp;
456 typedef png_struct * png_structp;
457 typedef png_struct * * png_structpp;
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.
468 typedef struct png_info_def png_info;
469 typedef png_info * png_infop;
470 typedef const png_info * png_const_infop;
471 typedef png_info * * png_infopp;
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'.
484 typedef png_struct * PNG_RESTRICT png_structrp;
485 typedef const png_struct * PNG_RESTRICT png_const_structrp;
486 typedef png_info * PNG_RESTRICT png_inforp;
487 typedef const png_info * PNG_RESTRICT png_const_inforp;
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).
493 typedef struct png_color_struct
499 typedef png_color * png_colorp;
500 typedef const png_color * png_const_colorp;
501 typedef png_color * * png_colorpp;
503 typedef struct png_color_16_struct
505 png_byte index; /* used for palette files */
506 png_uint_16 red; /* for use in red green blue files */
509 png_uint_16 gray; /* for use in grayscale files */
511 typedef png_color_16 * png_color_16p;
512 typedef const png_color_16 * png_const_color_16p;
513 typedef png_color_16 * * png_color_16pp;
515 typedef struct png_color_8_struct
517 png_byte red; /* for use in red green blue files */
520 png_byte gray; /* for use in grayscale files */
521 png_byte alpha; /* for alpha channel files */
523 typedef png_color_8 * png_color_8p;
524 typedef const png_color_8 * png_const_color_8p;
525 typedef png_color_8 * * png_color_8pp;
528 * The following two structures are used for the in-core representation
531 typedef struct png_sPLT_entry_struct
537 png_uint_16 frequency;
539 typedef png_sPLT_entry * png_sPLT_entryp;
540 typedef const png_sPLT_entry * png_const_sPLT_entryp;
541 typedef png_sPLT_entry * * png_sPLT_entrypp;
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.
548 typedef struct png_sPLT_struct
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 */
555 typedef png_sPLT_t * png_sPLT_tp;
556 typedef const png_sPLT_t * png_const_sPLT_tp;
557 typedef png_sPLT_t * * png_sPLT_tpp;
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.
577 typedef struct png_text_struct
579 int compression; /* compression value:
584 png_charp key; /* keyword, 1-79 character description of "text" */
585 png_charp text; /* comment, may be an empty string (ie "")
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
591 png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
592 chars or a NULL pointer */
596 /* Adding PNG Color pick feature.*/
597 typedef enum _Png_Color_Pick_Region_
599 PNG_COLORPICK_TOP = 0,
600 PNG_COLORPICK_MIDDLE,
601 PNG_COLORPICK_BOTTOM,
604 struct _Png_Color_Pick_Struct_
615 PngColorPickRegion region;
617 typedef struct _Png_Color_Pick_Struct_ PngPickColor; /* TODO : PngPickColor will be changed to PngColorPick in future*/
618 /* VD_TIZEN_ONLY_END */
620 typedef png_text * png_textp;
621 typedef const png_text * png_const_textp;
622 typedef png_text * * png_textpp;
625 /* Supported compression types for text in PNG files (tEXt, and zTXt).
626 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
627 #define PNG_TEXT_COMPRESSION_NONE_WR -3
628 #define PNG_TEXT_COMPRESSION_zTXt_WR -2
629 #define PNG_TEXT_COMPRESSION_NONE -1
630 #define PNG_TEXT_COMPRESSION_zTXt 0
631 #define PNG_ITXT_COMPRESSION_NONE 1
632 #define PNG_ITXT_COMPRESSION_zTXt 2
633 #define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
635 /* png_time is a way to hold the time in an machine independent way.
636 * Two conversions are provided, both from time_t and struct tm. There
637 * is no portable way to convert to either of these structures, as far
638 * as I know. If you know of a portable way, send it to me. As a side
639 * note - PNG has always been Year 2000 compliant!
641 typedef struct png_time_struct
643 png_uint_16 year; /* full year, as in, 1995 */
644 png_byte month; /* month of year, 1 - 12 */
645 png_byte day; /* day of month, 1 - 31 */
646 png_byte hour; /* hour of day, 0 - 23 */
647 png_byte minute; /* minute of hour, 0 - 59 */
648 png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
650 typedef png_time * png_timep;
651 typedef const png_time * png_const_timep;
652 typedef png_time * * png_timepp;
654 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
655 defined(PNG_USER_CHUNKS_SUPPORTED)
656 /* png_unknown_chunk is a structure to hold queued chunks for which there is
657 * no specific support. The idea is that we can use this to queue
658 * up private chunks for output even though the library doesn't actually
659 * know about their semantics.
661 * The data in the structure is set by libpng on read and used on write.
663 typedef struct png_unknown_chunk_t
665 png_byte name[5]; /* Textual chunk name with '\0' terminator */
666 png_byte *data; /* Data, should not be modified on read! */
669 /* On write 'location' must be set using the flag values listed below.
670 * Notice that on read it is set by libpng however the values stored have
671 * more bits set than are listed below. Always treat the value as a
672 * bitmask. On write set only one bit - setting multiple bits may cause the
673 * chunk to be written in multiple places.
675 png_byte location; /* mode of operation at read time */
679 typedef png_unknown_chunk * png_unknown_chunkp;
680 typedef const png_unknown_chunk * png_const_unknown_chunkp;
681 typedef png_unknown_chunk * * png_unknown_chunkpp;
684 /* Flag values for the unknown chunk location byte. */
685 #define PNG_HAVE_IHDR 0x01
686 #define PNG_HAVE_PLTE 0x02
687 #define PNG_AFTER_IDAT 0x08
689 /* Maximum positive integer used in PNG is (2^31)-1 */
690 #define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
691 #define PNG_UINT_32_MAX ((png_uint_32)(-1))
692 #define PNG_SIZE_MAX ((size_t)(-1))
694 /* These are constants for fixed point values encoded in the
695 * PNG specification manner (x100000)
697 #define PNG_FP_1 100000
698 #define PNG_FP_HALF 50000
699 #define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
700 #define PNG_FP_MIN (-PNG_FP_MAX)
702 /* These describe the color_type field in png_info. */
703 /* color type masks */
704 #define PNG_COLOR_MASK_PALETTE 1
705 #define PNG_COLOR_MASK_COLOR 2
706 #define PNG_COLOR_MASK_ALPHA 4
708 /* color types. Note that not all combinations are legal */
709 #define PNG_COLOR_TYPE_GRAY 0
710 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
711 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
712 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
713 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
715 #define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
716 #define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
718 /* This is for compression type. PNG 1.0-1.2 only define the single type. */
719 #define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
720 #define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
722 /* This is for filter type. PNG 1.0-1.2 only define the single type. */
723 #define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
724 #define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
725 #define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
727 /* These are for the interlacing type. These values should NOT be changed. */
728 #define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
729 #define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
730 #define PNG_INTERLACE_LAST 2 /* Not a valid value */
732 /* These are for the oFFs chunk. These values should NOT be changed. */
733 #define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
734 #define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
735 #define PNG_OFFSET_LAST 2 /* Not a valid value */
737 /* These are for the pCAL chunk. These values should NOT be changed. */
738 #define PNG_EQUATION_LINEAR 0 /* Linear transformation */
739 #define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
740 #define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
741 #define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
742 #define PNG_EQUATION_LAST 4 /* Not a valid value */
744 /* These are for the sCAL chunk. These values should NOT be changed. */
745 #define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
746 #define PNG_SCALE_METER 1 /* meters per pixel */
747 #define PNG_SCALE_RADIAN 2 /* radians per pixel */
748 #define PNG_SCALE_LAST 3 /* Not a valid value */
750 /* These are for the pHYs chunk. These values should NOT be changed. */
751 #define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
752 #define PNG_RESOLUTION_METER 1 /* pixels/meter */
753 #define PNG_RESOLUTION_LAST 2 /* Not a valid value */
755 /* These are for the sRGB chunk. These values should NOT be changed. */
756 #define PNG_sRGB_INTENT_PERCEPTUAL 0
757 #define PNG_sRGB_INTENT_RELATIVE 1
758 #define PNG_sRGB_INTENT_SATURATION 2
759 #define PNG_sRGB_INTENT_ABSOLUTE 3
760 #define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
762 /* This is for text chunks */
763 #define PNG_KEYWORD_MAX_LENGTH 79
765 /* Maximum number of entries in PLTE/sPLT/tRNS arrays */
766 #define PNG_MAX_PALETTE_LENGTH 256
768 /* These determine if an ancillary chunk's data has been successfully read
769 * from the PNG header, or if the application has filled in the corresponding
770 * data in the info_struct to be written into the output file. The values
771 * of the PNG_INFO_<chunk> defines should NOT be changed.
773 #define PNG_INFO_gAMA 0x0001U
774 #define PNG_INFO_sBIT 0x0002U
775 #define PNG_INFO_cHRM 0x0004U
776 #define PNG_INFO_PLTE 0x0008U
777 #define PNG_INFO_tRNS 0x0010U
778 #define PNG_INFO_bKGD 0x0020U
779 #define PNG_INFO_hIST 0x0040U
780 #define PNG_INFO_pHYs 0x0080U
781 #define PNG_INFO_oFFs 0x0100U
782 #define PNG_INFO_tIME 0x0200U
783 #define PNG_INFO_pCAL 0x0400U
784 #define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
785 #define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
786 #define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
787 #define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
788 #define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
789 #define PNG_INFO_eXIf 0x10000U /* GR-P, 1.6.31 */
790 #ifdef PNG_APNG_SUPPORTED
791 #define PNG_INFO_acTL 0x20000U
792 #define PNG_INFO_fcTL 0x40000U
795 /* This is used for the transformation routines, as some of them
796 * change these values for the row. It also should enable using
797 * the routines for other purposes.
799 typedef struct png_row_info_struct
801 png_uint_32 width; /* width of row */
802 size_t rowbytes; /* number of bytes in row */
803 png_byte color_type; /* color type of row */
804 png_byte bit_depth; /* bit depth of row */
805 png_byte channels; /* number of channels (1, 2, 3, or 4) */
806 png_byte pixel_depth; /* bits per pixel (depth * channels) */
809 typedef png_row_info * png_row_infop;
810 typedef png_row_info * * png_row_infopp;
812 /* These are the function types for the I/O functions and for the functions
813 * that allow the user to override the default I/O functions with his or her
814 * own. The png_error_ptr type should match that of user-supplied warning
815 * and error functions, while the png_rw_ptr type should match that of the
816 * user read/write data functions. Note that the 'write' function must not
817 * modify the buffer it is passed. The 'read' function, on the other hand, is
818 * expected to return the read data in the buffer.
820 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
821 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
822 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
823 typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
825 typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
828 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
829 typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
830 typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
831 #ifdef PNG_APNG_SUPPORTED
832 typedef PNG_CALLBACK(void, *png_progressive_frame_ptr, (png_structp,
836 /* The following callback receives png_uint_32 row_number, int pass for the
837 * png_bytep data of the row. When transforming an interlaced image the
838 * row number is the row number within the sub-image of the interlace pass, so
839 * the value will increase to the height of the sub-image (not the full image)
840 * then reset to 0 for the next pass.
842 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
843 * find the output pixel (x,y) given an interlaced sub-image pixel
844 * (row,col,pass). (See below for these macros.)
846 typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
850 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
851 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
852 typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
856 #ifdef PNG_USER_CHUNKS_SUPPORTED
857 typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
858 png_unknown_chunkp));
860 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
861 /* not used anywhere */
862 /* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
865 #ifdef PNG_SETJMP_SUPPORTED
866 /* This must match the function definition in <setjmp.h>, and the application
867 * must include this before png.h to obtain the definition of jmp_buf. The
868 * function is required to be PNG_NORETURN, but this is not checked. If the
869 * function does return the application will crash via an abort() or similar
872 * If you get a warning here while building the library you may need to make
873 * changes to ensure that pnglibconf.h records the calling convention used by
874 * your compiler. This may be very difficult - try using a different compiler
875 * to build the library!
877 PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
880 /* Transform masks for the high-level interface */
881 #define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
882 #define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
883 #define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
884 #define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
885 #define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
886 #define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
887 #define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
888 #define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
889 #define PNG_TRANSFORM_BGR 0x0080 /* read and write */
890 #define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
891 #define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
892 #define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
893 #define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
894 /* Added to libpng-1.2.34 */
895 #define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
896 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
897 /* Added to libpng-1.4.0 */
898 #define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
899 /* Added to libpng-1.5.4 */
900 #define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
901 #if INT_MAX >= 0x8000 /* else this might break */
902 #define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
905 /* Flags for MNG supported features */
906 #define PNG_FLAG_MNG_EMPTY_PLTE 0x01
907 #define PNG_FLAG_MNG_FILTER_64 0x04
908 #define PNG_ALL_MNG_FEATURES 0x05
910 /* NOTE: prior to 1.5 these functions had no 'API' style declaration,
911 * this allowed the zlib default functions to be used on Windows
912 * platforms. In 1.5 the zlib default malloc (which just calls malloc and
913 * ignores the first argument) should be completely compatible with the
916 typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
918 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
920 /* Section 4: exported functions
921 * Here are the function definitions most commonly used. This is not
922 * the place to find out how to use libpng. See libpng-manual.txt for the
923 * full explanation, see example.c for the summary. This just provides
924 * a simple one line description of the use of each function.
926 * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
927 * pngconf.h and in the *.dfn files in the scripts directory.
929 * PNG_EXPORT(ordinal, type, name, (args));
931 * ordinal: ordinal that is used while building
932 * *.def files. The ordinal value is only
933 * relevant when preprocessing png.h with
934 * the *.dfn files for building symbol table
935 * entries, and are removed by pngconf.h.
936 * type: return type of the function
937 * name: function name
938 * args: function arguments, with types
940 * When we wish to append attributes to a function prototype we use
941 * the PNG_EXPORTA() macro instead.
943 * PNG_EXPORTA(ordinal, type, name, (args), attributes);
945 * ordinal, type, name, and args: same as in PNG_EXPORT().
946 * attributes: function attributes
949 /* Returns the version number of the library */
950 PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
952 /* Tell lib we have already handled the first <num_bytes> magic bytes.
953 * Handling more than 8 bytes from the beginning of the file is an error.
955 PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
957 /* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
958 * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
959 * signature, and non-zero otherwise. Having num_to_check == 0 or
960 * start > 7 will always fail (ie return non-zero).
962 PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, size_t start,
963 size_t num_to_check));
965 /* Simple signature checking function. This is the same as calling
966 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
968 #define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
970 /* Allocate and initialize png_ptr struct for reading, and any other memory. */
971 PNG_EXPORTA(4, png_structp, png_create_read_struct,
972 (png_const_charp user_png_ver, png_voidp error_ptr,
973 png_error_ptr error_fn, png_error_ptr warn_fn),
976 /* Allocate and initialize png_ptr struct for writing, and any other memory */
977 PNG_EXPORTA(5, png_structp, png_create_write_struct,
978 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
979 png_error_ptr warn_fn),
982 PNG_EXPORT(6, size_t, png_get_compression_buffer_size,
983 (png_const_structrp png_ptr));
985 PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
988 /* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
991 #ifdef PNG_SETJMP_SUPPORTED
992 /* This function returns the jmp_buf built in to *png_ptr. It must be
993 * supplied with an appropriate 'longjmp' function to use on that jmp_buf
994 * unless the default error function is overridden in which case NULL is
995 * acceptable. The size of the jmp_buf is checked against the actual size
996 * allocated by the library - the call will return NULL on a mismatch
997 * indicating an ABI mismatch.
999 PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
1000 png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
1001 # define png_jmpbuf(png_ptr) \
1002 (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
1004 # define png_jmpbuf(png_ptr) \
1005 (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
1007 /* This function should be used by libpng applications in place of
1008 * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
1009 * will use it; otherwise it will call PNG_ABORT(). This function was
1010 * added in libpng-1.5.0.
1012 PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
1015 #ifdef PNG_READ_SUPPORTED
1016 /* Reset the compression stream */
1017 PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
1020 /* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1021 #ifdef PNG_USER_MEM_SUPPORTED
1022 PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
1023 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1024 png_error_ptr warn_fn,
1025 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1027 PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
1028 (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
1029 png_error_ptr warn_fn,
1030 png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
1034 /* Write the PNG file signature. */
1035 PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
1037 /* Write a PNG chunk - size, type, (optional) data, CRC. */
1038 PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
1039 chunk_name, png_const_bytep data, size_t length));
1041 /* Write the start of a PNG chunk - length and chunk name. */
1042 PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
1043 png_const_bytep chunk_name, png_uint_32 length));
1045 /* Write the data of a PNG chunk started with png_write_chunk_start(). */
1046 PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
1047 png_const_bytep data, size_t length));
1049 /* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1050 PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
1052 /* Allocate and initialize the info structure */
1053 PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
1056 /* DEPRECATED: this function allowed init structures to be created using the
1057 * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
1058 * the API will be removed in the future.
1060 PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
1061 size_t png_info_struct_size), PNG_DEPRECATED);
1063 /* Writes all the PNG information before the image. */
1064 PNG_EXPORT(20, void, png_write_info_before_PLTE,
1065 (png_structrp png_ptr, png_const_inforp info_ptr));
1066 PNG_EXPORT(21, void, png_write_info,
1067 (png_structrp png_ptr, png_const_inforp info_ptr));
1069 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1070 /* Read the information before the actual image data. */
1071 PNG_EXPORT(22, void, png_read_info,
1072 (png_structrp png_ptr, png_inforp info_ptr));
1075 #ifdef PNG_TIME_RFC1123_SUPPORTED
1076 /* Convert to a US string format: there is no localization support in this
1077 * routine. The original implementation used a 29 character buffer in
1078 * png_struct, this will be removed in future versions.
1080 #if PNG_LIBPNG_VER < 10700
1081 /* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
1082 PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
1083 png_const_timep ptime),PNG_DEPRECATED);
1085 PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
1086 png_const_timep ptime));
1089 #ifdef PNG_CONVERT_tIME_SUPPORTED
1090 /* Convert from a struct tm to png_time */
1091 PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
1092 const struct tm * ttime));
1094 /* Convert from time_t to png_time. Uses gmtime() */
1095 PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
1096 #endif /* CONVERT_tIME */
1098 #ifdef PNG_READ_EXPAND_SUPPORTED
1099 /* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1100 PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
1101 PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
1102 PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
1103 PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
1106 #ifdef PNG_READ_EXPAND_16_SUPPORTED
1107 /* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
1108 * of a tRNS chunk if present.
1110 PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
1113 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
1114 /* Use blue, green, red order for pixels. */
1115 PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
1118 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1119 /* Expand the grayscale to 24-bit RGB if necessary. */
1120 PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
1123 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1124 /* Reduce RGB to grayscale. */
1125 #define PNG_ERROR_ACTION_NONE 1
1126 #define PNG_ERROR_ACTION_WARN 2
1127 #define PNG_ERROR_ACTION_ERROR 3
1128 #define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
1130 PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
1131 int error_action, double red, double green))
1132 PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
1133 int error_action, png_fixed_point red, png_fixed_point green))
1135 PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
1139 #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
1140 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
1141 png_colorp palette));
1144 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1145 /* How the alpha channel is interpreted - this affects how the color channels
1146 * of a PNG file are returned to the calling application when an alpha channel,
1147 * or a tRNS chunk in a palette file, is present.
1149 * This has no effect on the way pixels are written into a PNG output
1150 * datastream. The color samples in a PNG datastream are never premultiplied
1151 * with the alpha samples.
1153 * The default is to return data according to the PNG specification: the alpha
1154 * channel is a linear measure of the contribution of the pixel to the
1155 * corresponding composited pixel, and the color channels are unassociated
1156 * (not premultiplied). The gamma encoded color channels must be scaled
1157 * according to the contribution and to do this it is necessary to undo
1158 * the encoding, scale the color values, perform the composition and re-encode
1159 * the values. This is the 'PNG' mode.
1161 * The alternative is to 'associate' the alpha with the color information by
1162 * storing color channel values that have been scaled by the alpha.
1163 * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
1164 * (the latter being the two common names for associated alpha color channels).
1166 * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
1167 * value is equal to the maximum value.
1169 * The final choice is to gamma encode the alpha channel as well. This is
1170 * broken because, in practice, no implementation that uses this choice
1171 * correctly undoes the encoding before handling alpha composition. Use this
1172 * choice only if other serious errors in the software or hardware you use
1173 * mandate it; the typical serious error is for dark halos to appear around
1174 * opaque areas of the composited PNG image because of arithmetic overflow.
1176 * The API function png_set_alpha_mode specifies which of these choices to use
1177 * with an enumerated 'mode' value and the gamma of the required output:
1179 #define PNG_ALPHA_PNG 0 /* according to the PNG standard */
1180 #define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
1181 #define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
1182 #define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
1183 #define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
1184 #define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
1186 PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
1187 double output_gamma))
1188 PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
1189 int mode, png_fixed_point output_gamma))
1192 #if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1193 /* The output_gamma value is a screen gamma in libpng terminology: it expresses
1194 * how to decode the output values, not how they are encoded.
1196 #define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
1197 #define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
1198 #define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
1199 #define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
1202 /* The following are examples of calls to png_set_alpha_mode to achieve the
1203 * required overall gamma correction and, where necessary, alpha
1204 * premultiplication.
1206 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1207 * This is the default libpng handling of the alpha channel - it is not
1208 * pre-multiplied into the color components. In addition the call states
1209 * that the output is for a sRGB system and causes all PNG files without gAMA
1210 * chunks to be assumed to be encoded using sRGB.
1212 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1213 * In this case the output is assumed to be something like an sRGB conformant
1214 * display preceded by a power-law lookup table of power 1.45. This is how
1215 * early Mac systems behaved.
1217 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
1218 * This is the classic Jim Blinn approach and will work in academic
1219 * environments where everything is done by the book. It has the shortcoming
1220 * of assuming that input PNG data with no gamma information is linear - this
1221 * is unlikely to be correct unless the PNG files where generated locally.
1222 * Most of the time the output precision will be so low as to show
1223 * significant banding in dark areas of the image.
1225 * png_set_expand_16(pp);
1226 * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
1227 * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
1228 * are assumed to have the sRGB encoding if not marked with a gamma value and
1229 * the output is always 16 bits per component. This permits accurate scaling
1230 * and processing of the data. If you know that your input PNG files were
1231 * generated locally you might need to replace PNG_DEFAULT_sRGB with the
1232 * correct value for your system.
1234 * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
1235 * If you just need to composite the PNG image onto an existing background
1236 * and if you control the code that does this you can use the optimization
1237 * setting. In this case you just copy completely opaque pixels to the
1238 * output. For pixels that are not completely transparent (you just skip
1239 * those) you do the composition math using png_composite or png_composite_16
1240 * below then encode the resultant 8-bit or 16-bit values to match the output
1244 * If neither the PNG nor the standard linear encoding work for you because
1245 * of the software or hardware you use then you have a big problem. The PNG
1246 * case will probably result in halos around the image. The linear encoding
1247 * will probably result in a washed out, too bright, image (it's actually too
1248 * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
1249 * substantially reduce the halos. Alternatively try:
1251 * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
1252 * This option will also reduce the halos, but there will be slight dark
1253 * halos round the opaque parts of the image where the background is light.
1254 * In the OPTIMIZED mode the halos will be light halos where the background
1255 * is dark. Take your pick - the halos are unavoidable unless you can get
1256 * your hardware/software fixed! (The OPTIMIZED approach is slightly
1259 * When the default gamma of PNG files doesn't match the output gamma.
1260 * If you have PNG files with no gamma information png_set_alpha_mode allows
1261 * you to provide a default gamma, but it also sets the output gamma to the
1262 * matching value. If you know your PNG files have a gamma that doesn't
1263 * match the output you can take advantage of the fact that
1264 * png_set_alpha_mode always sets the output gamma but only sets the PNG
1265 * default if it is not already set:
1267 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
1268 * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
1269 * The first call sets both the default and the output gamma values, the
1270 * second call overrides the output gamma without changing the default. This
1271 * is easier than achieving the same effect with png_set_gamma. You must use
1272 * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
1273 * fire if more than one call to png_set_alpha_mode and png_set_background is
1274 * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
1278 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1279 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
1282 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
1283 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1284 PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
1287 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
1288 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1289 PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
1292 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
1293 /* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1294 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
1296 /* The values of the PNG_FILLER_ defines should NOT be changed */
1297 # define PNG_FILLER_BEFORE 0
1298 # define PNG_FILLER_AFTER 1
1299 /* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
1300 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
1301 png_uint_32 filler, int flags));
1302 #endif /* READ_FILLER || WRITE_FILLER */
1304 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
1305 /* Swap bytes in 16-bit depth files. */
1306 PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
1309 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
1310 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1311 PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
1314 #if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
1315 defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1316 /* Swap packing order of pixels in bytes. */
1317 PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
1320 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
1321 /* Converts files to legal bit depths. */
1322 PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
1326 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
1327 defined(PNG_WRITE_INTERLACING_SUPPORTED)
1328 /* Have the code handle the interlacing. Returns the number of passes.
1329 * MUST be called before png_read_update_info or png_start_read_image,
1330 * otherwise it will not have the desired effect. Note that it is still
1331 * necessary to call png_read_row or png_read_rows png_get_image_height
1332 * times for each pass.
1334 PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
1337 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
1338 /* Invert monochrome files */
1339 PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
1342 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1343 /* Handle alpha and tRNS by replacing with a background color. Prior to
1344 * libpng-1.5.4 this API must not be called before the PNG file header has been
1345 * read. Doing so will result in unexpected behavior and possible warnings or
1346 * errors if the PNG file contains a bKGD chunk.
1348 PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
1349 png_const_color_16p background_color, int background_gamma_code,
1350 int need_expand, double background_gamma))
1351 PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
1352 png_const_color_16p background_color, int background_gamma_code,
1353 int need_expand, png_fixed_point background_gamma))
1355 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1356 # define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1357 # define PNG_BACKGROUND_GAMMA_SCREEN 1
1358 # define PNG_BACKGROUND_GAMMA_FILE 2
1359 # define PNG_BACKGROUND_GAMMA_UNIQUE 3
1362 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1363 /* Scale a 16-bit depth file down to 8-bit, accurately. */
1364 PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
1367 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1368 #define PNG_READ_16_TO_8_SUPPORTED /* Name prior to 1.5.4 */
1369 /* Strip the second byte of information from a 16-bit depth file. */
1370 PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
1373 #ifdef PNG_READ_QUANTIZE_SUPPORTED
1374 /* Turn on quantizing, and reduce the palette to the number of colors
1377 PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
1378 png_colorp palette, int num_palette, int maximum_colors,
1379 png_const_uint_16p histogram, int full_quantize));
1382 #ifdef PNG_READ_GAMMA_SUPPORTED
1383 /* The threshold on gamma processing is configurable but hard-wired into the
1384 * library. The following is the floating point variant.
1386 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
1388 /* Handle gamma correction. Screen_gamma=(display_exponent).
1389 * NOTE: this API simply sets the screen and file gamma values. It will
1390 * therefore override the value for gamma in a PNG file if it is called after
1391 * the file header has been read - use with care - call before reading the PNG
1392 * file for best results!
1394 * These routines accept the same gamma values as png_set_alpha_mode (described
1395 * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
1396 * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
1397 * is the inverse of a 'screen gamma' value.
1399 PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
1400 double screen_gamma, double override_file_gamma))
1401 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
1402 png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
1405 #ifdef PNG_WRITE_FLUSH_SUPPORTED
1406 /* Set how many lines between output flushes - 0 for no flushing */
1407 PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
1408 /* Flush the current PNG output buffer */
1409 PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
1412 /* Optional update palette with requested transformations */
1413 PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
1415 /* Optional call to update the users info structure */
1416 PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
1417 png_inforp info_ptr));
1419 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1420 /* Read one or more rows of image data. */
1421 PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
1422 png_bytepp display_row, png_uint_32 num_rows));
1425 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1426 /* Read a row of data. */
1427 PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
1428 png_bytep display_row));
1431 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1432 /* Read the whole image into memory at once. */
1433 PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
1436 /* Write a row of image data */
1437 PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
1438 png_const_bytep row));
1440 /* Write a few rows of image data: (*row) is not written; however, the type
1441 * is declared as writeable to maintain compatibility with previous versions
1442 * of libpng and to allow the 'display_row' array from read_rows to be passed
1443 * unchanged to write_rows.
1445 PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
1446 png_uint_32 num_rows));
1448 /* Write the image data */
1449 PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
1451 /* Write the end of the PNG file. */
1452 PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
1453 png_inforp info_ptr));
1455 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1456 /* Read the end of the PNG file. */
1457 PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
1460 /* Free any memory associated with the png_info_struct */
1461 PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
1462 png_infopp info_ptr_ptr));
1464 /* Free any memory associated with the png_struct and the png_info_structs */
1465 PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
1466 png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1468 /* Free any memory associated with the png_struct and the png_info_structs */
1469 PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
1470 png_infopp info_ptr_ptr));
1472 /* Set the libpng method of handling chunk CRC errors */
1473 PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
1476 /* Values for png_set_crc_action() say how to handle CRC errors in
1477 * ancillary and critical chunks, and whether to use the data contained
1478 * therein. Note that it is impossible to "discard" data in a critical
1479 * chunk. For versions prior to 0.90, the action was always error/quit,
1480 * whereas in version 0.90 and later, the action for CRC errors in ancillary
1481 * chunks is warn/discard. These values should NOT be changed.
1483 * value action:critical action:ancillary
1485 #define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1486 #define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1487 #define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1488 #define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1489 #define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1490 #define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1492 #ifdef PNG_WRITE_SUPPORTED
1493 /* These functions give the user control over the scan-line filtering in
1494 * libpng and the compression methods used by zlib. These functions are
1495 * mainly useful for testing, as the defaults should work with most users.
1496 * Those users who are tight on memory or want faster performance at the
1497 * expense of compression can modify them. See the compression library
1498 * header file (zlib.h) for an explanation of the compression functions.
1501 /* Set the filtering method(s) used by libpng. Currently, the only valid
1502 * value for "method" is 0.
1504 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
1508 /* Flags for png_set_filter() to say which filters to use. The flags
1509 * are chosen so that they don't conflict with real filter types
1510 * below, in case they are supplied instead of the #defined constants.
1511 * These values should NOT be changed.
1513 #define PNG_NO_FILTERS 0x00
1514 #define PNG_FILTER_NONE 0x08
1515 #define PNG_FILTER_SUB 0x10
1516 #define PNG_FILTER_UP 0x20
1517 #define PNG_FILTER_AVG 0x40
1518 #define PNG_FILTER_PAETH 0x80
1519 #define PNG_FAST_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP)
1520 #define PNG_ALL_FILTERS (PNG_FAST_FILTERS | PNG_FILTER_AVG | PNG_FILTER_PAETH)
1522 /* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1523 * These defines should NOT be changed.
1525 #define PNG_FILTER_VALUE_NONE 0
1526 #define PNG_FILTER_VALUE_SUB 1
1527 #define PNG_FILTER_VALUE_UP 2
1528 #define PNG_FILTER_VALUE_AVG 3
1529 #define PNG_FILTER_VALUE_PAETH 4
1530 #define PNG_FILTER_VALUE_LAST 5
1532 #ifdef PNG_WRITE_SUPPORTED
1533 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1534 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
1535 int heuristic_method, int num_weights, png_const_doublep filter_weights,
1536 png_const_doublep filter_costs))
1537 PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
1538 (png_structrp png_ptr, int heuristic_method, int num_weights,
1539 png_const_fixed_point_p filter_weights,
1540 png_const_fixed_point_p filter_costs))
1541 #endif /* WRITE_WEIGHTED_FILTER */
1543 /* The following are no longer used and will be removed from libpng-1.7: */
1544 #define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1545 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1546 #define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1547 #define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1549 /* Set the library compression level. Currently, valid values range from
1550 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1551 * (0 - no compression, 9 - "maximal" compression). Note that tests have
1552 * shown that zlib compression levels 3-6 usually perform as well as level 9
1553 * for PNG images, and do considerably fewer calculations. In the future,
1554 * these values may not correspond directly to the zlib compression levels.
1556 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1557 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
1560 PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
1563 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
1566 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1567 * smaller value of window_bits if it can do so safely.
1569 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
1572 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
1574 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1576 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1577 /* Also set zlib parameters for compressing non-IDAT chunks */
1578 PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
1581 PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
1584 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
1587 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1588 * smaller value of window_bits if it can do so safely.
1590 PNG_EXPORT(225, void, png_set_text_compression_window_bits,
1591 (png_structrp png_ptr, int window_bits));
1593 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
1595 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1598 /* These next functions are called for input/output, memory, and error
1599 * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1600 * and call standard C I/O routines such as fread(), fwrite(), and
1601 * fprintf(). These functions can be made to use other I/O routines
1602 * at run time for those applications that need to handle I/O in a
1603 * different manner by calling png_set_???_fn(). See libpng-manual.txt for
1607 #ifdef PNG_STDIO_SUPPORTED
1608 /* Initialize the input/output for the PNG file to the default functions. */
1609 PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
1612 /* Replace the (error and abort), and warning functions with user
1613 * supplied functions. If no messages are to be printed you must still
1614 * write and use replacement functions. The replacement error_fn should
1615 * still do a longjmp to the last setjmp location if you are using this
1616 * method of error handling. If error_fn or warning_fn is NULL, the
1617 * default function will be used.
1620 PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
1621 png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1623 /* Return the user pointer associated with the error functions */
1624 PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
1626 /* Replace the default data output functions with a user supplied one(s).
1627 * If buffered output is not used, then output_flush_fn can be set to NULL.
1628 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1629 * output_flush_fn will be ignored (and thus can be NULL).
1630 * It is probably a mistake to use NULL for output_flush_fn if
1631 * write_data_fn is not also NULL unless you have built libpng with
1632 * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1633 * default flush function, which uses the standard *FILE structure, will
1636 PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
1637 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1639 /* Replace the default data input function with a user supplied one. */
1640 PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
1641 png_rw_ptr read_data_fn));
1643 /* Return the user pointer associated with the I/O functions */
1644 PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
1646 PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
1647 png_read_status_ptr read_row_fn));
1649 PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
1650 png_write_status_ptr write_row_fn));
1652 #ifdef PNG_USER_MEM_SUPPORTED
1653 /* Replace the default memory allocation functions with user supplied one(s). */
1654 PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
1655 png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1656 /* Return the user pointer associated with the memory functions */
1657 PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
1660 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1661 PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
1662 png_user_transform_ptr read_user_transform_fn));
1665 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1666 PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
1667 png_user_transform_ptr write_user_transform_fn));
1670 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1671 PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
1672 png_voidp user_transform_ptr, int user_transform_depth,
1673 int user_transform_channels));
1674 /* Return the user pointer associated with the user transform functions */
1675 PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
1676 (png_const_structrp png_ptr));
1679 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
1680 /* Return information about the row currently being processed. Note that these
1681 * APIs do not fail but will return unexpected results if called outside a user
1682 * transform callback. Also note that when transforming an interlaced image the
1683 * row number is the row number within the sub-image of the interlace pass, so
1684 * the value will increase to the height of the sub-image (not the full image)
1685 * then reset to 0 for the next pass.
1687 * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
1688 * find the output pixel (x,y) given an interlaced sub-image pixel
1689 * (row,col,pass). (See below for these macros.)
1691 PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
1692 PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
1695 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1696 /* This callback is called only for *unknown* chunks. If
1697 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
1698 * chunks to be treated as unknown, however in this case the callback must do
1699 * any processing required by the chunk (e.g. by calling the appropriate
1702 * There is no write support - on write, by default, all the chunks in the
1703 * 'unknown' list are written in the specified position.
1705 * The integer return from the callback function is interpreted thus:
1707 * negative: An error occurred; png_chunk_error will be called.
1708 * zero: The chunk was not handled, the chunk will be saved. A critical
1709 * chunk will cause an error at this point unless it is to be saved.
1710 * positive: The chunk was handled, libpng will ignore/discard it.
1712 * See "INTERACTION WITH USER CHUNK CALLBACKS" below for important notes about
1713 * how this behavior will change in libpng 1.7
1715 PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
1716 png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
1719 #ifdef PNG_USER_CHUNKS_SUPPORTED
1720 PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
1723 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1724 /* Sets the function callbacks for the push reader, and a pointer to a
1725 * user-defined structure available to the callback functions.
1727 PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
1728 png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
1729 png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
1731 /* Returns the user pointer associated with the push read functions */
1732 PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
1733 (png_const_structrp png_ptr));
1735 /* Function to be called when data becomes available */
1736 PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
1737 png_inforp info_ptr, png_bytep buffer, size_t buffer_size));
1739 /* A function which may be called *only* within png_process_data to stop the
1740 * processing of any more data. The function returns the number of bytes
1741 * remaining, excluding any that libpng has cached internally. A subsequent
1742 * call to png_process_data must supply these bytes again. If the argument
1743 * 'save' is set to true the routine will first save all the pending data and
1744 * will always return 0.
1746 PNG_EXPORT(219, size_t, png_process_data_pause, (png_structrp, int save));
1748 /* A function which may be called *only* outside (after) a call to
1749 * png_process_data. It returns the number of bytes of data to skip in the
1750 * input. Normally it will return 0, but if it returns a non-zero value the
1751 * application must skip than number of bytes of input data and pass the
1752 * following data to the next call to png_process_data.
1754 PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
1756 /* Function that combines rows. 'new_row' is a flag that should come from
1757 * the callback and be non-NULL if anything needs to be done; the library
1758 * stores its own version of the new data internally and ignores the passed
1761 PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
1762 png_bytep old_row, png_const_bytep new_row));
1763 #endif /* PROGRESSIVE_READ */
1765 PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
1766 png_alloc_size_t size), PNG_ALLOCATED);
1767 /* Added at libpng version 1.4.0 */
1768 PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
1769 png_alloc_size_t size), PNG_ALLOCATED);
1771 /* Added at libpng version 1.2.4 */
1772 PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
1773 png_alloc_size_t size), PNG_ALLOCATED);
1775 /* Frees a pointer allocated by png_malloc() */
1776 PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
1778 /* Free data that was allocated internally */
1779 PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
1780 png_inforp info_ptr, png_uint_32 free_me, int num));
1782 /* Reassign responsibility for freeing existing data, whether allocated
1783 * by libpng or by the application; this works on the png_info structure passed
1784 * in, it does not change the state for other png_info structures.
1786 * It is unlikely that this function works correctly as of 1.6.0 and using it
1787 * may result either in memory leaks or double free of allocated data.
1789 PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
1790 png_inforp info_ptr, int freer, png_uint_32 mask));
1792 /* Assignments for png_data_freer */
1793 #define PNG_DESTROY_WILL_FREE_DATA 1
1794 #define PNG_SET_WILL_FREE_DATA 1
1795 #define PNG_USER_WILL_FREE_DATA 2
1796 /* Flags for png_ptr->free_me and info_ptr->free_me */
1797 #define PNG_FREE_HIST 0x0008U
1798 #define PNG_FREE_ICCP 0x0010U
1799 #define PNG_FREE_SPLT 0x0020U
1800 #define PNG_FREE_ROWS 0x0040U
1801 #define PNG_FREE_PCAL 0x0080U
1802 #define PNG_FREE_SCAL 0x0100U
1803 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
1804 # define PNG_FREE_UNKN 0x0200U
1806 /* PNG_FREE_LIST 0x0400U removed in 1.6.0 because it is ignored */
1807 #define PNG_FREE_PLTE 0x1000U
1808 #define PNG_FREE_TRNS 0x2000U
1809 #define PNG_FREE_TEXT 0x4000U
1810 #define PNG_FREE_EXIF 0x8000U /* Added at libpng-1.6.31 */
1811 #define PNG_FREE_ALL 0xffffU
1812 #define PNG_FREE_MUL 0x4220U /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
1814 #ifdef PNG_USER_MEM_SUPPORTED
1815 PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
1816 png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
1817 PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
1818 png_voidp ptr), PNG_DEPRECATED);
1821 #ifdef PNG_ERROR_TEXT_SUPPORTED
1822 /* Fatal error in PNG image of libpng - can't continue */
1823 PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
1824 png_const_charp error_message), PNG_NORETURN);
1826 /* The same, but the chunk name is prepended to the error string. */
1827 PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
1828 png_const_charp error_message), PNG_NORETURN);
1831 /* Fatal error in PNG image of libpng - can't continue */
1832 PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
1833 # define png_error(s1,s2) png_err(s1)
1834 # define png_chunk_error(s1,s2) png_err(s1)
1837 #ifdef PNG_WARNINGS_SUPPORTED
1838 /* Non-fatal error in libpng. Can continue, but may have a problem. */
1839 PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
1840 png_const_charp warning_message));
1842 /* Non-fatal error in libpng, chunk name is prepended to message. */
1843 PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
1844 png_const_charp warning_message));
1846 # define png_warning(s1,s2) ((void)(s1))
1847 # define png_chunk_warning(s1,s2) ((void)(s1))
1850 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
1851 /* Benign error in libpng. Can continue, but may have a problem.
1852 * User can choose whether to handle as a fatal error or as a warning. */
1853 PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
1854 png_const_charp warning_message));
1856 #ifdef PNG_READ_SUPPORTED
1857 /* Same, chunk name is prepended to message (only during read) */
1858 PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
1859 png_const_charp warning_message));
1862 PNG_EXPORT(109, void, png_set_benign_errors,
1863 (png_structrp png_ptr, int allowed));
1865 # ifdef PNG_ALLOW_BENIGN_ERRORS
1866 # define png_benign_error png_warning
1867 # define png_chunk_benign_error png_chunk_warning
1869 # define png_benign_error png_error
1870 # define png_chunk_benign_error png_chunk_error
1874 /* The png_set_<chunk> functions are for storing values in the png_info_struct.
1875 * Similarly, the png_get_<chunk> calls are used to read values from the
1876 * png_info_struct, either storing the parameters in the passed variables, or
1877 * setting pointers into the png_info_struct where the data is stored. The
1878 * png_get_<chunk> functions return a non-zero value if the data was available
1879 * in info_ptr, or return zero and do not change any of the parameters if the
1880 * data was not available.
1882 * These functions should be used instead of directly accessing png_info
1883 * to avoid problems with future changes in the size and internal layout of
1886 /* Returns "flag" if chunk data is valid in info_ptr. */
1887 PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
1888 png_const_inforp info_ptr, png_uint_32 flag));
1890 /* Returns number of bytes needed to hold a transformed row. */
1891 PNG_EXPORT(111, size_t, png_get_rowbytes, (png_const_structrp png_ptr,
1892 png_const_inforp info_ptr));
1894 #ifdef PNG_INFO_IMAGE_SUPPORTED
1895 /* Returns row_pointers, which is an array of pointers to scanlines that was
1896 * returned from png_read_png().
1898 PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
1899 png_const_inforp info_ptr));
1901 /* Set row_pointers, which is an array of pointers to scanlines for use
1902 * by png_write_png().
1904 PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
1905 png_inforp info_ptr, png_bytepp row_pointers));
1908 /* Returns number of color channels in image. */
1909 PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
1910 png_const_inforp info_ptr));
1912 #ifdef PNG_EASY_ACCESS_SUPPORTED
1913 /* Returns image width in pixels. */
1914 PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
1915 png_const_inforp info_ptr));
1917 /* Returns image height in pixels. */
1918 PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
1919 png_const_inforp info_ptr));
1921 /* Returns image bit_depth. */
1922 PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
1923 png_const_inforp info_ptr));
1925 /* Returns image color_type. */
1926 PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
1927 png_const_inforp info_ptr));
1929 /* Returns image filter_type. */
1930 PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
1931 png_const_inforp info_ptr));
1933 /* Returns image interlace_type. */
1934 PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
1935 png_const_inforp info_ptr));
1937 /* Returns image compression_type. */
1938 PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
1939 png_const_inforp info_ptr));
1941 /* Returns image resolution in pixels per meter, from pHYs chunk data. */
1942 PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
1943 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1944 PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
1945 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1946 PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
1947 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1949 /* Returns pixel aspect ratio, computed from pHYs chunk data. */
1950 PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
1951 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1952 PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
1953 (png_const_structrp png_ptr, png_const_inforp info_ptr))
1955 /* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
1956 PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
1957 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1958 PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
1959 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1960 PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
1961 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1962 PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
1963 (png_const_structrp png_ptr, png_const_inforp info_ptr));
1965 #endif /* EASY_ACCESS */
1967 #ifdef PNG_READ_SUPPORTED
1968 /* Returns pointer to signature string read from PNG header */
1969 PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
1970 png_const_inforp info_ptr));
1973 #ifdef PNG_bKGD_SUPPORTED
1974 PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
1975 png_inforp info_ptr, png_color_16p *background));
1978 #ifdef PNG_bKGD_SUPPORTED
1979 PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
1980 png_inforp info_ptr, png_const_color_16p background));
1983 #ifdef PNG_cHRM_SUPPORTED
1984 PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
1985 png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
1986 double *red_y, double *green_x, double *green_y, double *blue_x,
1988 PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
1989 png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
1990 double *green_X, double *green_Y, double *green_Z, double *blue_X,
1991 double *blue_Y, double *blue_Z))
1992 PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
1993 (png_const_structrp png_ptr, png_const_inforp info_ptr,
1994 png_fixed_point *int_white_x, png_fixed_point *int_white_y,
1995 png_fixed_point *int_red_x, png_fixed_point *int_red_y,
1996 png_fixed_point *int_green_x, png_fixed_point *int_green_y,
1997 png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
1998 PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
1999 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2000 png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
2001 png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
2002 png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
2003 png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
2004 png_fixed_point *int_blue_Z))
2007 #ifdef PNG_cHRM_SUPPORTED
2008 PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
2009 png_inforp info_ptr,
2010 double white_x, double white_y, double red_x, double red_y, double green_x,
2011 double green_y, double blue_x, double blue_y))
2012 PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
2013 png_inforp info_ptr, double red_X, double red_Y, double red_Z,
2014 double green_X, double green_Y, double green_Z, double blue_X,
2015 double blue_Y, double blue_Z))
2016 PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
2017 png_inforp info_ptr, png_fixed_point int_white_x,
2018 png_fixed_point int_white_y, png_fixed_point int_red_x,
2019 png_fixed_point int_red_y, png_fixed_point int_green_x,
2020 png_fixed_point int_green_y, png_fixed_point int_blue_x,
2021 png_fixed_point int_blue_y))
2022 PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
2023 png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
2024 png_fixed_point int_red_Z, png_fixed_point int_green_X,
2025 png_fixed_point int_green_Y, png_fixed_point int_green_Z,
2026 png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
2027 png_fixed_point int_blue_Z))
2030 #ifdef PNG_eXIf_SUPPORTED
2031 PNG_EXPORT(246, png_uint_32, png_get_eXIf, (png_const_structrp png_ptr,
2032 png_inforp info_ptr, png_bytep *exif));
2033 PNG_EXPORT(247, void, png_set_eXIf, (png_const_structrp png_ptr,
2034 png_inforp info_ptr, png_bytep exif));
2036 PNG_EXPORT(248, png_uint_32, png_get_eXIf_1, (png_const_structrp png_ptr,
2037 png_const_inforp info_ptr, png_uint_32 *num_exif, png_bytep *exif));
2038 PNG_EXPORT(249, void, png_set_eXIf_1, (png_const_structrp png_ptr,
2039 png_inforp info_ptr, png_uint_32 num_exif, png_bytep exif));
2042 #ifdef PNG_gAMA_SUPPORTED
2043 PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
2044 png_const_inforp info_ptr, double *file_gamma))
2045 PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
2046 (png_const_structrp png_ptr, png_const_inforp info_ptr,
2047 png_fixed_point *int_file_gamma))
2050 #ifdef PNG_gAMA_SUPPORTED
2051 PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
2052 png_inforp info_ptr, double file_gamma))
2053 PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
2054 png_inforp info_ptr, png_fixed_point int_file_gamma))
2057 #ifdef PNG_hIST_SUPPORTED
2058 PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
2059 png_inforp info_ptr, png_uint_16p *hist));
2060 PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
2061 png_inforp info_ptr, png_const_uint_16p hist));
2064 PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
2065 png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
2066 int *bit_depth, int *color_type, int *interlace_method,
2067 int *compression_method, int *filter_method));
2069 PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
2070 png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2071 int color_type, int interlace_method, int compression_method,
2072 int filter_method));
2074 #ifdef PNG_oFFs_SUPPORTED
2075 PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
2076 png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
2080 #ifdef PNG_oFFs_SUPPORTED
2081 PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
2082 png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2086 #ifdef PNG_pCAL_SUPPORTED
2087 PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
2088 png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
2089 png_int_32 *X1, int *type, int *nparams, png_charp *units,
2090 png_charpp *params));
2093 #ifdef PNG_pCAL_SUPPORTED
2094 PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
2095 png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
2096 int type, int nparams, png_const_charp units, png_charpp params));
2099 #ifdef PNG_pHYs_SUPPORTED
2100 PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
2101 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2105 #ifdef PNG_pHYs_SUPPORTED
2106 PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
2107 png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2110 PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
2111 png_inforp info_ptr, png_colorp *palette, int *num_palette));
2113 PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
2114 png_inforp info_ptr, png_const_colorp palette, int num_palette));
2116 #ifdef PNG_sBIT_SUPPORTED
2117 PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
2118 png_inforp info_ptr, png_color_8p *sig_bit));
2121 #ifdef PNG_sBIT_SUPPORTED
2122 PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
2123 png_inforp info_ptr, png_const_color_8p sig_bit));
2126 #ifdef PNG_sRGB_SUPPORTED
2127 PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
2128 png_const_inforp info_ptr, int *file_srgb_intent));
2131 #ifdef PNG_sRGB_SUPPORTED
2132 PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
2133 png_inforp info_ptr, int srgb_intent));
2134 PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
2135 png_inforp info_ptr, int srgb_intent));
2138 #ifdef PNG_iCCP_SUPPORTED
2139 PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
2140 png_inforp info_ptr, png_charpp name, int *compression_type,
2141 png_bytepp profile, png_uint_32 *proflen));
2144 #ifdef PNG_iCCP_SUPPORTED
2145 PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
2146 png_inforp info_ptr, png_const_charp name, int compression_type,
2147 png_const_bytep profile, png_uint_32 proflen));
2150 #ifdef PNG_sPLT_SUPPORTED
2151 PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
2152 png_inforp info_ptr, png_sPLT_tpp entries));
2155 #ifdef PNG_sPLT_SUPPORTED
2156 PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
2157 png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
2160 #ifdef PNG_TEXT_SUPPORTED
2161 /* png_get_text also returns the number of text chunks in *num_text */
2162 PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
2163 png_inforp info_ptr, png_textp *text_ptr, int *num_text));
2166 /* Note while png_set_text() will accept a structure whose text,
2167 * language, and translated keywords are NULL pointers, the structure
2168 * returned by png_get_text will always contain regular
2169 * zero-terminated C strings. They might be empty strings but
2170 * they will never be NULL pointers.
2173 #ifdef PNG_TEXT_SUPPORTED
2174 PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
2175 png_inforp info_ptr, png_const_textp text_ptr, int num_text));
2178 #ifdef PNG_tIME_SUPPORTED
2179 PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
2180 png_inforp info_ptr, png_timep *mod_time));
2183 #ifdef PNG_tIME_SUPPORTED
2184 PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
2185 png_inforp info_ptr, png_const_timep mod_time));
2188 #ifdef PNG_tRNS_SUPPORTED
2189 PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
2190 png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
2191 png_color_16p *trans_color));
2194 #ifdef PNG_tRNS_SUPPORTED
2195 PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
2196 png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
2197 png_const_color_16p trans_color));
2200 #ifdef PNG_sCAL_SUPPORTED
2201 PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
2202 png_const_inforp info_ptr, int *unit, double *width, double *height))
2203 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
2204 defined(PNG_FLOATING_POINT_SUPPORTED)
2205 /* NOTE: this API is currently implemented using floating point arithmetic,
2206 * consequently it can only be used on systems with floating point support.
2207 * In any case the range of values supported by png_fixed_point is small and it
2208 * is highly recommended that png_get_sCAL_s be used instead.
2210 PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
2211 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2212 png_fixed_point *width, png_fixed_point *height))
2214 PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
2215 (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
2216 png_charpp swidth, png_charpp sheight));
2218 PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
2219 png_inforp info_ptr, int unit, double width, double height))
2220 PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
2221 png_inforp info_ptr, int unit, png_fixed_point width,
2222 png_fixed_point height))
2223 PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
2224 png_inforp info_ptr, int unit,
2225 png_const_charp swidth, png_const_charp sheight));
2228 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
2229 /* Provide the default handling for all unknown chunks or, optionally, for
2230 * specific unknown chunks.
2232 * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
2233 * ignored and the default was used, the per-chunk setting only had an effect on
2234 * write. If you wish to have chunk-specific handling on read in code that must
2235 * work on earlier versions you must use a user chunk callback to specify the
2236 * desired handling (keep or discard.)
2238 * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
2239 * parameter is interpreted as follows:
2242 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2243 * Known chunks: do normal libpng processing, do not keep the chunk (but
2244 * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
2245 * Unknown chunks: for a specific chunk use the global default, when used
2246 * as the default discard the chunk data.
2247 * PNG_HANDLE_CHUNK_NEVER:
2248 * Discard the chunk data.
2249 * PNG_HANDLE_CHUNK_IF_SAFE:
2250 * Keep the chunk data if the chunk is not critical else raise a chunk
2252 * PNG_HANDLE_CHUNK_ALWAYS:
2253 * Keep the chunk data.
2255 * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
2256 * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
2257 * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
2258 * it simply resets the behavior to the libpng default.
2260 * INTERACTION WITH USER CHUNK CALLBACKS:
2261 * The per-chunk handling is always used when there is a png_user_chunk_ptr
2262 * callback and the callback returns 0; the chunk is then always stored *unless*
2263 * it is critical and the per-chunk setting is other than ALWAYS. Notice that
2264 * the global default is *not* used in this case. (In effect the per-chunk
2265 * value is incremented to at least IF_SAFE.)
2267 * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
2268 * per-chunk defaults will be honored. If you want to preserve the current
2269 * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
2270 * as the default - if you don't do this libpng 1.6 will issue a warning.
2272 * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
2273 * earlier simply return '1' (handled).
2275 * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
2276 * If this is *not* set known chunks will always be handled by libpng and
2277 * will never be stored in the unknown chunk list. Known chunks listed to
2278 * png_set_keep_unknown_chunks will have no effect. If it is set then known
2279 * chunks listed with a keep other than AS_DEFAULT will *never* be processed
2280 * by libpng, in addition critical chunks must either be processed by the
2281 * callback or saved.
2283 * The IHDR and IEND chunks must not be listed. Because this turns off the
2284 * default handling for chunks that would otherwise be recognized the
2285 * behavior of libpng transformations may well become incorrect!
2288 * When writing chunks the options only apply to the chunks specified by
2289 * png_set_unknown_chunks (below), libpng will *always* write known chunks
2290 * required by png_set_ calls and will always write the core critical chunks
2291 * (as required for PLTE).
2293 * Each chunk in the png_set_unknown_chunks list is looked up in the
2294 * png_set_keep_unknown_chunks list to find the keep setting, this is then
2295 * interpreted as follows:
2297 * PNG_HANDLE_CHUNK_AS_DEFAULT:
2298 * Write safe-to-copy chunks and write other chunks if the global
2299 * default is set to _ALWAYS, otherwise don't write this chunk.
2300 * PNG_HANDLE_CHUNK_NEVER:
2301 * Do not write the chunk.
2302 * PNG_HANDLE_CHUNK_IF_SAFE:
2303 * Write the chunk if it is safe-to-copy, otherwise do not write it.
2304 * PNG_HANDLE_CHUNK_ALWAYS:
2307 * Note that the default behavior is effectively the opposite of the read case -
2308 * in read unknown chunks are not stored by default, in write they are written
2309 * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
2310 * - on write the safe-to-copy bit is checked, on read the critical bit is
2311 * checked and on read if the chunk is critical an error will be raised.
2315 * If num_chunks is positive, then the "keep" parameter specifies the manner
2316 * for handling only those chunks appearing in the chunk_list array,
2317 * otherwise the chunk list array is ignored.
2319 * If num_chunks is 0 the "keep" parameter specifies the default behavior for
2320 * unknown chunks, as described above.
2322 * If num_chunks is negative, then the "keep" parameter specifies the manner
2323 * for handling all unknown chunks plus all chunks recognized by libpng
2324 * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
2325 * be processed by libpng.
2327 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2328 PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
2329 int keep, png_const_bytep chunk_list, int num_chunks));
2330 #endif /* HANDLE_AS_UNKNOWN */
2332 /* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
2333 * the result is therefore true (non-zero) if special handling is required,
2334 * false for the default handling.
2336 PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
2337 png_const_bytep chunk_name));
2338 #endif /* SET_UNKNOWN_CHUNKS */
2340 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
2341 PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
2342 png_inforp info_ptr, png_const_unknown_chunkp unknowns,
2344 /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
2345 * unknowns to the location currently stored in the png_struct. This is
2346 * invariably the wrong value on write. To fix this call the following API
2347 * for each chunk in the list with the correct location. If you know your
2348 * code won't be compiled on earlier versions you can rely on
2349 * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
2350 * the correct thing.
2353 PNG_EXPORT(175, void, png_set_unknown_chunk_location,
2354 (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
2356 PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
2357 png_inforp info_ptr, png_unknown_chunkpp entries));
2360 /* Png_free_data() will turn off the "valid" flag for anything it frees.
2361 * If you need to turn it off for a chunk that your application has freed,
2362 * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2364 PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
2365 png_inforp info_ptr, int mask));
2367 #ifdef PNG_INFO_IMAGE_SUPPORTED
2368 /* The "params" pointer is currently not used and is for future expansion. */
2369 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
2370 PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
2371 int transforms, png_voidp params));
2373 #ifdef PNG_WRITE_SUPPORTED
2374 PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
2375 int transforms, png_voidp params));
2379 PNG_EXPORT(180, png_const_charp, png_get_copyright,
2380 (png_const_structrp png_ptr));
2381 PNG_EXPORT(181, png_const_charp, png_get_header_ver,
2382 (png_const_structrp png_ptr));
2383 PNG_EXPORT(182, png_const_charp, png_get_header_version,
2384 (png_const_structrp png_ptr));
2385 PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
2386 (png_const_structrp png_ptr));
2388 #ifdef PNG_MNG_FEATURES_SUPPORTED
2389 PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
2390 png_uint_32 mng_features_permitted));
2393 /* For use in png_set_keep_unknown, added to version 1.2.6 */
2394 #define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2395 #define PNG_HANDLE_CHUNK_NEVER 1
2396 #define PNG_HANDLE_CHUNK_IF_SAFE 2
2397 #define PNG_HANDLE_CHUNK_ALWAYS 3
2398 #define PNG_HANDLE_CHUNK_LAST 4
2400 /* Strip the prepended error numbers ("#nnn ") from error and warning
2401 * messages before passing them to the error or warning handler.
2403 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
2404 PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
2405 png_uint_32 strip_mode));
2408 /* Added in libpng-1.2.6 */
2409 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
2410 PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
2411 png_uint_32 user_width_max, png_uint_32 user_height_max));
2412 PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
2413 (png_const_structrp png_ptr));
2414 PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
2415 (png_const_structrp png_ptr));
2416 /* Added in libpng-1.4.0 */
2417 PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
2418 png_uint_32 user_chunk_cache_max));
2419 PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
2420 (png_const_structrp png_ptr));
2421 /* Added in libpng-1.4.1 */
2422 PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
2423 png_alloc_size_t user_chunk_cache_max));
2424 PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
2425 (png_const_structrp png_ptr));
2428 #if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
2429 PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
2430 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2432 PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
2433 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2435 PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
2436 (png_const_structrp png_ptr, png_const_inforp info_ptr));
2438 PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
2439 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2440 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2441 PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
2442 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2445 PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
2446 png_const_inforp info_ptr))
2447 #ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
2448 PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
2449 (png_const_structrp png_ptr, png_const_inforp info_ptr))
2452 # ifdef PNG_pHYs_SUPPORTED
2453 PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
2454 png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
2457 #endif /* INCH_CONVERSIONS */
2459 /* Added in libpng-1.4.0 */
2460 #ifdef PNG_IO_STATE_SUPPORTED
2461 PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
2463 /* Removed from libpng 1.6; use png_get_io_chunk_type. */
2464 PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
2467 PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
2468 (png_const_structrp png_ptr));
2470 /* The flags returned by png_get_io_state() are the following: */
2471 # define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2472 # define PNG_IO_READING 0x0001 /* currently reading */
2473 # define PNG_IO_WRITING 0x0002 /* currently writing */
2474 # define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2475 # define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2476 # define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2477 # define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2478 # define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2479 # define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2480 #endif /* IO_STATE */
2482 /* Interlace support. The following macros are always defined so that if
2483 * libpng interlace handling is turned off the macros may be used to handle
2484 * interlaced images within the application.
2486 #define PNG_INTERLACE_ADAM7_PASSES 7
2488 /* Two macros to return the first row and first column of the original,
2489 * full, image which appears in a given pass. 'pass' is in the range 0
2490 * to 6 and the result is in the range 0 to 7.
2492 #define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
2493 #define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
2495 /* A macro to return the offset between pixels in the output row for a pair of
2496 * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
2497 * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
2498 * COL_OFFSET is from one column to the next, within a row.
2500 #define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
2501 #define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
2503 /* Two macros to help evaluate the number of rows or columns in each
2504 * pass. This is expressed as a shift - effectively log2 of the number or
2505 * rows or columns in each 8x8 tile of the original image.
2507 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
2508 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
2510 /* Hence two macros to determine the number of rows or columns in a given
2511 * pass of an image given its height or width. In fact these macros may
2512 * return non-zero even though the sub-image is empty, because the other
2513 * dimension may be empty for a small image.
2515 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
2516 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
2517 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
2518 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
2520 /* For the reader row callbacks (both progressive and sequential) it is
2521 * necessary to find the row in the output image given a row in an interlaced
2522 * image, so two more macros:
2524 #define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
2525 (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
2526 #define PNG_COL_FROM_PASS_COL(x_in, pass) \
2527 (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
2529 /* Two macros which return a boolean (0 or 1) saying whether the given row
2530 * or column is in a particular pass. These use a common utility macro that
2531 * returns a mask for a given pass - the offset 'off' selects the row or
2532 * column version. The mask has the appropriate bit set for each column in
2535 #define PNG_PASS_MASK(pass,off) ( \
2536 ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
2537 ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
2539 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
2540 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
2541 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
2542 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
2544 #ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2545 /* With these routines we avoid an integer divide, which will be slower on
2546 * most machines. However, it does take more operations than the corresponding
2547 * divide method, so it may be slower on a few RISC systems. There are two
2548 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2550 * Note that the rounding factors are NOT supposed to be the same! 128 and
2551 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2554 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2557 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2559 # define png_composite(composite, fg, alpha, bg) \
2561 png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2562 * (png_uint_16)(alpha) \
2563 + (png_uint_16)(bg)*(png_uint_16)(255 \
2564 - (png_uint_16)(alpha)) + 128); \
2565 (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); \
2568 # define png_composite_16(composite, fg, alpha, bg) \
2570 png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2571 * (png_uint_32)(alpha) \
2572 + (png_uint_32)(bg)*(65535 \
2573 - (png_uint_32)(alpha)) + 32768); \
2574 (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); \
2577 #else /* Standard method using integer division */
2579 # define png_composite(composite, fg, alpha, bg) \
2581 (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2582 (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2585 # define png_composite_16(composite, fg, alpha, bg) \
2587 (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2588 (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
2590 #endif /* READ_COMPOSITE_NODIV */
2592 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
2593 PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
2594 PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
2595 PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
2598 PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
2599 png_const_bytep buf));
2600 /* No png_get_int_16 -- may be added if there's a real need for it. */
2602 /* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2603 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2604 PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
2606 #ifdef PNG_SAVE_INT_32_SUPPORTED
2607 PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
2610 /* Place a 16-bit number into a buffer in PNG byte order.
2611 * The parameter is declared unsigned int, not png_uint_16,
2612 * just to avoid potential problems on pre-ANSI C compilers.
2614 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
2615 PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
2616 /* No png_save_int_16 -- may be added if there's a real need for it. */
2619 #ifdef PNG_USE_READ_MACROS
2620 /* Inline macros to do direct reads of bytes from the input buffer.
2621 * The png_get_int_32() routine assumes we are using two's complement
2622 * format for negative values, which is almost certainly true.
2624 # define PNG_get_uint_32(buf) \
2625 (((png_uint_32)(*(buf)) << 24) + \
2626 ((png_uint_32)(*((buf) + 1)) << 16) + \
2627 ((png_uint_32)(*((buf) + 2)) << 8) + \
2628 ((png_uint_32)(*((buf) + 3))))
2630 /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
2631 * function) incorrectly returned a value of type png_uint_32.
2633 # define PNG_get_uint_16(buf) \
2635 (((unsigned int)(*(buf)) << 8) + \
2636 ((unsigned int)(*((buf) + 1)))))
2638 # define PNG_get_int_32(buf) \
2639 ((png_int_32)((*(buf) & 0x80) \
2640 ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
2641 : (png_int_32)png_get_uint_32(buf)))
2643 /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
2644 * but defining a macro name prefixed with PNG_PREFIX.
2647 # define png_get_uint_32(buf) PNG_get_uint_32(buf)
2648 # define png_get_uint_16(buf) PNG_get_uint_16(buf)
2649 # define png_get_int_32(buf) PNG_get_int_32(buf)
2653 /* No macros; revert to the (redefined) function */
2654 # define PNG_get_uint_32 (png_get_uint_32)
2655 # define PNG_get_uint_16 (png_get_uint_16)
2656 # define PNG_get_int_32 (png_get_int_32)
2660 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
2661 PNG_EXPORT(242, void, png_set_check_for_invalid_index,
2662 (png_structrp png_ptr, int allowed));
2663 # ifdef PNG_GET_PALETTE_MAX_SUPPORTED
2664 PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
2665 png_const_infop info_ptr));
2667 #endif /* CHECK_FOR_INVALID_INDEX */
2669 /*******************************************************************************
2670 * Section 5: SIMPLIFIED API
2671 *******************************************************************************
2673 * Please read the documentation in libpng-manual.txt (TODO: write said
2674 * documentation) if you don't understand what follows.
2676 * The simplified API hides the details of both libpng and the PNG file format
2677 * itself. It allows PNG files to be read into a very limited number of
2678 * in-memory bitmap formats or to be written from the same formats. If these
2679 * formats do not accommodate your needs then you can, and should, use the more
2680 * sophisticated APIs above - these support a wide variety of in-memory formats
2681 * and a wide variety of sophisticated transformations to those formats as well
2682 * as a wide variety of APIs to manipulate ancillary information.
2684 * To read a PNG file using the simplified API:
2686 * 1) Declare a 'png_image' structure (see below) on the stack, set the
2687 * version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
2688 * (this is REQUIRED, your program may crash if you don't do it.)
2689 * 2) Call the appropriate png_image_begin_read... function.
2690 * 3) Set the png_image 'format' member to the required sample format.
2691 * 4) Allocate a buffer for the image and, if required, the color-map.
2692 * 5) Call png_image_finish_read to read the image and, if required, the
2693 * color-map into your buffers.
2695 * There are no restrictions on the format of the PNG input itself; all valid
2696 * color types, bit depths, and interlace methods are acceptable, and the
2697 * input image is transformed as necessary to the requested in-memory format
2698 * during the png_image_finish_read() step. The only caveat is that if you
2699 * request a color-mapped image from a PNG that is full-color or makes
2700 * complex use of an alpha channel the transformation is extremely lossy and the
2701 * result may look terrible.
2703 * To write a PNG file using the simplified API:
2705 * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
2706 * 2) Initialize the members of the structure that describe the image, setting
2707 * the 'format' member to the format of the image samples.
2708 * 3) Call the appropriate png_image_write... function with a pointer to the
2709 * image and, if necessary, the color-map to write the PNG data.
2711 * png_image is a structure that describes the in-memory format of an image
2712 * when it is being read or defines the in-memory format of an image that you
2715 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
2716 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
2718 #define PNG_IMAGE_VERSION 1
2720 typedef struct png_control *png_controlp;
2723 png_controlp opaque; /* Initialize to NULL, free with png_image_free */
2724 png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
2725 png_uint_32 width; /* Image width in pixels (columns) */
2726 png_uint_32 height; /* Image height in pixels (rows) */
2727 png_uint_32 format; /* Image format as defined below */
2728 png_uint_32 flags; /* A bit mask containing informational flags */
2729 png_uint_32 colormap_entries;
2730 /* Number of entries in the color-map */
2732 /* In the event of an error or warning the following field will be set to a
2733 * non-zero value and the 'message' field will contain a '\0' terminated
2734 * string with the libpng error or warning message. If both warnings and
2735 * an error were encountered, only the error is recorded. If there
2736 * are multiple warnings, only the first one is recorded.
2738 * The upper 30 bits of this value are reserved, the low two bits contain
2739 * a value as follows:
2741 # define PNG_IMAGE_WARNING 1
2742 # define PNG_IMAGE_ERROR 2
2744 * The result is a two-bit code such that a value more than 1 indicates
2745 * a failure in the API just called:
2747 * 0 - no warning or error
2750 * 3 - error preceded by warning
2752 # define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
2754 png_uint_32 warning_or_error;
2757 } png_image, *png_imagep;
2759 /* The samples of the image have one to four channels whose components have
2760 * original values in the range 0 to 1.0:
2762 * 1: A single gray or luminance channel (G).
2763 * 2: A gray/luminance channel and an alpha channel (GA).
2764 * 3: Three red, green, blue color channels (RGB).
2765 * 4: Three color channels and an alpha channel (RGBA).
2767 * The components are encoded in one of two ways:
2769 * a) As a small integer, value 0..255, contained in a single byte. For the
2770 * alpha channel the original value is simply value/255. For the color or
2771 * luminance channels the value is encoded according to the sRGB specification
2772 * and matches the 8-bit format expected by typical display devices.
2774 * The color/gray channels are not scaled (pre-multiplied) by the alpha
2775 * channel and are suitable for passing to color management software.
2777 * b) As a value in the range 0..65535, contained in a 2-byte integer. All
2778 * channels can be converted to the original value by dividing by 65535; all
2779 * channels are linear. Color channels use the RGB encoding (RGB end-points) of
2780 * the sRGB specification. This encoding is identified by the
2781 * PNG_FORMAT_FLAG_LINEAR flag below.
2783 * When the simplified API needs to convert between sRGB and linear colorspaces,
2784 * the actual sRGB transfer curve defined in the sRGB specification (see the
2785 * article at <https://en.wikipedia.org/wiki/SRGB>) is used, not the gamma=1/2.2
2786 * approximation used elsewhere in libpng.
2788 * When an alpha channel is present it is expected to denote pixel coverage
2789 * of the color or luminance channels and is returned as an associated alpha
2790 * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
2793 * The samples are either contained directly in the image data, between 1 and 8
2794 * bytes per pixel according to the encoding, or are held in a color-map indexed
2795 * by bytes in the image data. In the case of a color-map the color-map entries
2796 * are individual samples, encoded as above, and the image data has one byte per
2797 * pixel to select the relevant sample from the color-map.
2802 * #defines to be used in png_image::format. Each #define identifies a
2803 * particular layout of sample data and, if present, alpha values. There are
2804 * separate defines for each of the two component encodings.
2806 * A format is built up using single bit flag values. All combinations are
2807 * valid. Formats can be built up from the flag values or you can use one of
2808 * the predefined values below. When testing formats always use the FORMAT_FLAG
2809 * macros to test for individual features - future versions of the library may
2812 * When reading or writing color-mapped images the format should be set to the
2813 * format of the entries in the color-map then png_image_{read,write}_colormap
2814 * called to read or write the color-map and set the format correctly for the
2815 * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
2817 * NOTE: libpng can be built with particular features disabled. If you see
2818 * compiler errors because the definition of one of the following flags has been
2819 * compiled out it is because libpng does not have the required support. It is
2820 * possible, however, for the libpng configuration to enable the format on just
2821 * read or just write; in that case you may see an error at run time. You can
2822 * guard against this by checking for the definition of the appropriate
2823 * "_SUPPORTED" macro, one of:
2825 * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
2827 #define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
2828 #define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
2829 #define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2-byte channels else 1-byte */
2830 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
2832 #ifdef PNG_FORMAT_BGR_SUPPORTED
2833 # define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
2836 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
2837 # define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
2840 #define PNG_FORMAT_FLAG_ASSOCIATED_ALPHA 0x40U /* alpha channel is associated */
2842 /* Commonly used formats have predefined macros.
2844 * First the single byte (sRGB) formats:
2846 #define PNG_FORMAT_GRAY 0
2847 #define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
2848 #define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
2849 #define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
2850 #define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
2851 #define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
2852 #define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
2853 #define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
2854 #define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
2856 /* Then the linear 2-byte formats. When naming these "Y" is used to
2857 * indicate a luminance (gray) channel.
2859 #define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
2860 #define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
2861 #define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
2862 #define PNG_FORMAT_LINEAR_RGB_ALPHA \
2863 (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
2865 /* With color-mapped formats the image data is one byte for each pixel, the byte
2866 * is an index into the color-map which is formatted as above. To obtain a
2867 * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
2868 * to one of the above definitions, or you can use one of the definitions below.
2870 #define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
2871 #define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
2872 #define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
2873 #define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
2874 #define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
2875 #define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
2879 * These are convenience macros to derive information from a png_image
2880 * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
2881 * actual image sample values - either the entries in the color-map or the
2882 * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
2883 * for the pixels and will always return 1 for color-mapped formats. The
2884 * remaining macros return information about the rows in the image and the
2887 * NOTE: All the macros that take a png_image::format parameter are compile time
2888 * constants if the format parameter is, itself, a constant. Therefore these
2889 * macros can be used in array declarations and case labels where required.
2890 * Similarly the macros are also pre-processor constants (sizeof is not used) so
2891 * they can be used in #if tests.
2893 * First the information about the samples.
2895 #define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
2896 (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
2897 /* Return the total number of channels in a given format: 1..4 */
2899 #define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
2900 ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
2901 /* Return the size in bytes of a single component of a pixel or color-map
2902 * entry (as appropriate) in the image: 1 or 2.
2905 #define PNG_IMAGE_SAMPLE_SIZE(fmt)\
2906 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
2907 /* This is the size of the sample data for one sample. If the image is
2908 * color-mapped it is the size of one color-map entry (and image pixels are
2909 * one byte in size), otherwise it is the size of one image pixel.
2912 #define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
2913 (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
2914 /* The maximum size of the color-map required by the format expressed in a
2915 * count of components. This can be used to compile-time allocate a
2918 * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
2920 * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
2922 * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
2923 * information from one of the png_image_begin_read_ APIs and dynamically
2924 * allocate the required memory.
2927 /* Corresponding information about the pixels */
2928 #define PNG_IMAGE_PIXEL_(test,fmt)\
2929 (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
2931 #define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
2932 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
2933 /* The number of separate channels (components) in a pixel; 1 for a
2934 * color-mapped image.
2937 #define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
2938 PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
2939 /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
2943 #define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
2944 /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
2946 /* Information about the whole row, or whole image */
2947 #define PNG_IMAGE_ROW_STRIDE(image)\
2948 (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
2949 /* Return the total number of components in a single row of the image; this
2950 * is the minimum 'row stride', the minimum count of components between each
2951 * row. For a color-mapped image this is the minimum number of bytes in a
2954 * WARNING: this macro overflows for some images with more than one component
2955 * and very large image widths. libpng will refuse to process an image where
2956 * this macro would overflow.
2959 #define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
2960 (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
2961 /* Return the size, in bytes, of an image buffer given a png_image and a row
2962 * stride - the number of components to leave space for in each row.
2964 * WARNING: this macro overflows a 32-bit integer for some large PNG images,
2965 * libpng will refuse to process an image where such an overflow would occur.
2968 #define PNG_IMAGE_SIZE(image)\
2969 PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
2970 /* Return the size, in bytes, of the image in memory given just a png_image;
2971 * the row stride is the minimum stride required for the image.
2974 #define PNG_IMAGE_COLORMAP_SIZE(image)\
2975 (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
2976 /* Return the size, in bytes, of the color-map of this image. If the image
2977 * format is not a color-map format this will return a size sufficient for
2978 * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
2979 * you don't want to allocate a color-map in this case.
2984 * Flags containing additional information about the image are held in the
2985 * 'flags' field of png_image.
2987 #define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
2988 /* This indicates that the RGB values of the in-memory bitmap do not
2989 * correspond to the red, green and blue end-points defined by sRGB.
2992 #define PNG_IMAGE_FLAG_FAST 0x02
2993 /* On write emphasise speed over compression; the resultant PNG file will be
2994 * larger but will be produced significantly faster, particular for large
2995 * images. Do not use this option for images which will be distributed, only
2996 * used it when producing intermediate files that will be read back in
2997 * repeatedly. For a typical 24-bit image the option will double the read
2998 * speed at the cost of increasing the image size by 25%, however for many
2999 * more compressible images the PNG file can be 10 times larger with only a
3000 * slight speed gain.
3003 #define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
3004 /* On read if the image is a 16-bit per component image and there is no gAMA
3005 * or sRGB chunk assume that the components are sRGB encoded. Notice that
3006 * images output by the simplified API always have gamma information; setting
3007 * this flag only affects the interpretation of 16-bit images from an
3008 * external source. It is recommended that the application expose this flag
3009 * to the user; the user can normally easily recognize the difference between
3010 * linear and sRGB encoding. This flag has no effect on write - the data
3011 * passed to the write APIs must have the correct encoding (as defined
3014 * If the flag is not set (the default) input 16-bit per component data is
3015 * assumed to be linear.
3017 * NOTE: the flag can only be set after the png_image_begin_read_ call,
3018 * because that call initializes the 'flags' field.
3021 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
3025 * The png_image passed to the read APIs must have been initialized by setting
3026 * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
3028 #ifdef PNG_STDIO_SUPPORTED
3029 PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
3030 const char *file_name));
3031 /* The named file is opened for read and the image header is filled in
3032 * from the PNG header in the file.
3035 PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
3037 /* The PNG header is read from the stdio FILE object. */
3040 PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
3041 png_const_voidp memory, size_t size));
3042 /* The PNG header is read from the given memory buffer. */
3044 PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
3045 png_const_colorp background, void *buffer, png_int_32 row_stride,
3047 /* Finish reading the image into the supplied buffer and clean up the
3048 * png_image structure.
3050 * row_stride is the step, in byte or 2-byte units as appropriate,
3051 * between adjacent rows. A positive stride indicates that the top-most row
3052 * is first in the buffer - the normal top-down arrangement. A negative
3053 * stride indicates that the bottom-most row is first in the buffer.
3055 * background need only be supplied if an alpha channel must be removed from
3056 * a png_byte format and the removal is to be done by compositing on a solid
3057 * color; otherwise it may be NULL and any composition will be done directly
3058 * onto the buffer. The value is an sRGB color to use for the background,
3059 * for grayscale output the green channel is used.
3061 * background must be supplied when an alpha channel must be removed from a
3062 * single byte color-mapped output format, in other words if:
3064 * 1) The original format from png_image_begin_read_from_* had
3065 * PNG_FORMAT_FLAG_ALPHA set.
3066 * 2) The format set by the application does not.
3067 * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
3068 * PNG_FORMAT_FLAG_LINEAR *not* set.
3070 * For linear output removing the alpha channel is always done by compositing
3071 * on black and background is ignored.
3073 * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
3074 * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
3075 * image->colormap_entries will be updated to the actual number of entries
3076 * written to the colormap; this may be less than the original value.
3079 PNG_EXPORT(238, void, png_image_free, (png_imagep image));
3080 /* Free any data allocated by libpng in image->opaque, setting the pointer to
3081 * NULL. May be called at any time after the structure is initialized.
3083 #endif /* SIMPLIFIED_READ */
3085 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3088 * For write you must initialize a png_image structure to describe the image to
3089 * be written. To do this use memset to set the whole structure to 0 then
3090 * initialize fields describing your image.
3092 * version: must be set to PNG_IMAGE_VERSION
3093 * opaque: must be initialized to NULL
3094 * width: image width in pixels
3095 * height: image height in rows
3096 * format: the format of the data (image and color-map) you wish to write
3097 * flags: set to 0 unless one of the defined flags applies; set
3098 * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
3099 * values do not correspond to the colors in sRGB.
3100 * colormap_entries: set to the number of entries in the color-map (0 to 256)
3102 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3103 PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
3104 const char *file, int convert_to_8bit, const void *buffer,
3105 png_int_32 row_stride, const void *colormap));
3106 /* Write the image to the named file. */
3108 PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
3109 int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
3110 const void *colormap));
3111 /* Write the image to the given (FILE*). */
3112 #endif /* SIMPLIFIED_WRITE_STDIO */
3114 /* With all write APIs if image is in one of the linear formats with 16-bit
3115 * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
3116 * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
3117 * encoded PNG file is written.
3119 * With color-mapped data formats the colormap parameter point to a color-map
3120 * with at least image->colormap_entries encoded in the specified format. If
3121 * the format is linear the written PNG color-map will be converted to sRGB
3122 * regardless of the convert_to_8_bit flag.
3124 * With all APIs row_stride is handled as in the read APIs - it is the spacing
3125 * from one row to the next in component sized units (1 or 2 bytes) and if
3126 * negative indicates a bottom-up row layout in the buffer. If row_stride is
3127 * zero, libpng will calculate it for you from the image width and number of
3130 * Note that the write API does not support interlacing, sub-8-bit pixels or
3131 * most ancillary chunks. If you need to write text chunks (e.g. for copyright
3132 * notices) you need to use one of the other APIs.
3135 PNG_EXPORT(245, int, png_image_write_to_memory, (png_imagep image, void *memory,
3136 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8_bit,
3137 const void *buffer, png_int_32 row_stride, const void *colormap));
3138 /* Write the image to the given memory buffer. The function both writes the
3139 * whole PNG data stream to *memory and updates *memory_bytes with the count
3142 * 'memory' may be NULL. In this case *memory_bytes is not read however on
3143 * success the number of bytes which would have been written will still be
3144 * stored in *memory_bytes. On failure *memory_bytes will contain 0.
3146 * If 'memory' is not NULL it must point to memory[*memory_bytes] of
3149 * If the function returns success memory[*memory_bytes] (if 'memory' is not
3150 * NULL) contains the written PNG data. *memory_bytes will always be less
3151 * than or equal to the original value.
3153 * If the function returns false and *memory_bytes was not changed an error
3154 * occurred during write. If *memory_bytes was changed, or is not 0 if
3155 * 'memory' was NULL, the write would have succeeded but for the memory
3156 * buffer being too small. *memory_bytes contains the required number of
3157 * bytes and will be bigger that the original value.
3160 #define png_image_write_get_memory_size(image, size, convert_to_8_bit, buffer,\
3161 row_stride, colormap)\
3162 png_image_write_to_memory(&(image), 0, &(size), convert_to_8_bit, buffer,\
3163 row_stride, colormap)
3164 /* Return the amount of memory in 'size' required to compress this image.
3165 * The png_image structure 'image' must be filled in as in the above
3166 * function and must not be changed before the actual write call, the buffer
3167 * and all other parameters must also be identical to that in the final
3168 * write call. The 'size' variable need not be initialized.
3170 * NOTE: the macro returns true/false, if false is returned 'size' will be
3171 * set to zero and the write failed and probably will fail if tried again.
3174 /* You can pre-allocate the buffer by making sure it is of sufficient size
3175 * regardless of the amount of compression achieved. The buffer size will
3176 * always be bigger than the original image and it will never be filled. The
3177 * following macros are provided to assist in allocating the buffer.
3179 #define PNG_IMAGE_DATA_SIZE(image) (PNG_IMAGE_SIZE(image)+(image).height)
3180 /* The number of uncompressed bytes in the PNG byte encoding of the image;
3181 * uncompressing the PNG IDAT data will give this number of bytes.
3183 * NOTE: while PNG_IMAGE_SIZE cannot overflow for an image in memory this
3184 * macro can because of the extra bytes used in the PNG byte encoding. You
3185 * need to avoid this macro if your image size approaches 2^30 in width or
3186 * height. The same goes for the remainder of these macros; they all produce
3187 * bigger numbers than the actual in-memory image size.
3189 #ifndef PNG_ZLIB_MAX_SIZE
3190 # define PNG_ZLIB_MAX_SIZE(b) ((b)+(((b)+7U)>>3)+(((b)+63U)>>6)+11U)
3191 /* An upper bound on the number of compressed bytes given 'b' uncompressed
3192 * bytes. This is based on deflateBounds() in zlib; different
3193 * implementations of zlib compression may conceivably produce more data so
3194 * if your zlib implementation is not zlib itself redefine this macro
3199 #define PNG_IMAGE_COMPRESSED_SIZE_MAX(image)\
3200 PNG_ZLIB_MAX_SIZE((png_alloc_size_t)PNG_IMAGE_DATA_SIZE(image))
3201 /* An upper bound on the size of the data in the PNG IDAT chunks. */
3203 #define PNG_IMAGE_PNG_SIZE_MAX_(image, image_size)\
3204 ((8U/*sig*/+25U/*IHDR*/+16U/*gAMA*/+44U/*cHRM*/+12U/*IEND*/+\
3205 (((image).format&PNG_FORMAT_FLAG_COLORMAP)?/*colormap: PLTE, tRNS*/\
3206 12U+3U*(image).colormap_entries/*PLTE data*/+\
3207 (((image).format&PNG_FORMAT_FLAG_ALPHA)?\
3208 12U/*tRNS*/+(image).colormap_entries:0U):0U)+\
3209 12U)+(12U*((image_size)/PNG_ZBUF_SIZE))/*IDAT*/+(image_size))
3210 /* A helper for the following macro; if your compiler cannot handle the
3211 * following macro use this one with the result of
3212 * PNG_IMAGE_COMPRESSED_SIZE_MAX(image) as the second argument (most
3213 * compilers should handle this just fine.)
3216 #define PNG_IMAGE_PNG_SIZE_MAX(image)\
3217 PNG_IMAGE_PNG_SIZE_MAX_(image, PNG_IMAGE_COMPRESSED_SIZE_MAX(image))
3218 /* An upper bound on the total length of the PNG data stream for 'image'.
3219 * The result is of type png_alloc_size_t, on 32-bit systems this may
3220 * overflow even though PNG_IMAGE_DATA_SIZE does not overflow; the write will
3221 * run out of buffer space but return a corrected size which should work.
3223 #endif /* SIMPLIFIED_WRITE */
3224 /*******************************************************************************
3225 * END OF SIMPLIFIED API
3226 ******************************************************************************/
3227 #endif /* SIMPLIFIED_{READ|WRITE} */
3229 /*******************************************************************************
3230 * Section 6: IMPLEMENTATION OPTIONS
3231 *******************************************************************************
3233 * Support for arbitrary implementation-specific optimizations. The API allows
3234 * particular options to be turned on or off. 'Option' is the number of the
3235 * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
3236 * by the PNG_OPTION_ defines below.
3238 * HARDWARE: normally hardware capabilities, such as the Intel SSE instructions,
3239 * are detected at run time, however sometimes it may be impossible
3240 * to do this in user mode, in which case it is necessary to discover
3241 * the capabilities in an OS specific way. Such capabilities are
3242 * listed here when libpng has support for them and must be turned
3243 * ON by the application if present.
3245 * SOFTWARE: sometimes software optimizations actually result in performance
3246 * decrease on some architectures or systems, or with some sets of
3247 * PNG images. 'Software' options allow such optimizations to be
3248 * selected at run time.
3250 #ifdef PNG_SET_OPTION_SUPPORTED
3251 #ifdef PNG_ARM_NEON_API_SUPPORTED
3252 # define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
3254 #define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
3255 #define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
3256 #ifdef PNG_MIPS_MSA_API_SUPPORTED
3257 # define PNG_MIPS_MSA 6 /* HARDWARE: MIPS Msa SIMD instructions supported */
3259 #define PNG_IGNORE_ADLER32 8
3260 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
3261 # define PNG_POWERPC_VSX 10 /* HARDWARE: PowerPC VSX SIMD instructions supported */
3263 #define PNG_OPTION_NEXT 12 /* Next option - numbers must be even */
3265 /* Return values: NOTE: there are four values and 'off' is *not* zero */
3266 #define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
3267 #define PNG_OPTION_INVALID 1 /* Option number out of range */
3268 #define PNG_OPTION_OFF 2
3269 #define PNG_OPTION_ON 3
3271 PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
3273 #endif /* SET_OPTION */
3275 /*******************************************************************************
3276 * END OF HARDWARE AND SOFTWARE OPTIONS
3277 ******************************************************************************/
3278 #ifdef PNG_APNG_SUPPORTED
3279 PNG_EXPORT(250, png_uint_32, png_get_acTL, (png_structp png_ptr,
3280 png_infop info_ptr, png_uint_32 *num_frames, png_uint_32 *num_plays));
3282 PNG_EXPORT(251, png_uint_32, png_set_acTL, (png_structp png_ptr,
3283 png_infop info_ptr, png_uint_32 num_frames, png_uint_32 num_plays));
3285 PNG_EXPORT(252, png_uint_32, png_get_num_frames, (png_structp png_ptr,
3286 png_infop info_ptr));
3288 PNG_EXPORT(253, png_uint_32, png_get_num_plays, (png_structp png_ptr,
3289 png_infop info_ptr));
3291 PNG_EXPORT(254, png_uint_32, png_get_next_frame_fcTL,
3292 (png_structp png_ptr, png_infop info_ptr, png_uint_32 *width,
3293 png_uint_32 *height, png_uint_32 *x_offset, png_uint_32 *y_offset,
3294 png_uint_16 *delay_num, png_uint_16 *delay_den, png_byte *dispose_op,
3295 png_byte *blend_op));
3297 PNG_EXPORT(255, png_uint_32, png_set_next_frame_fcTL,
3298 (png_structp png_ptr, png_infop info_ptr, png_uint_32 width,
3299 png_uint_32 height, png_uint_32 x_offset, png_uint_32 y_offset,
3300 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
3301 png_byte blend_op));
3303 PNG_EXPORT(256, png_uint_32, png_get_next_frame_width,
3304 (png_structp png_ptr, png_infop info_ptr));
3305 PNG_EXPORT(257, png_uint_32, png_get_next_frame_height,
3306 (png_structp png_ptr, png_infop info_ptr));
3307 PNG_EXPORT(258, png_uint_32, png_get_next_frame_x_offset,
3308 (png_structp png_ptr, png_infop info_ptr));
3309 PNG_EXPORT(259, png_uint_32, png_get_next_frame_y_offset,
3310 (png_structp png_ptr, png_infop info_ptr));
3311 PNG_EXPORT(260, png_uint_16, png_get_next_frame_delay_num,
3312 (png_structp png_ptr, png_infop info_ptr));
3313 PNG_EXPORT(261, png_uint_16, png_get_next_frame_delay_den,
3314 (png_structp png_ptr, png_infop info_ptr));
3315 PNG_EXPORT(262, png_byte, png_get_next_frame_dispose_op,
3316 (png_structp png_ptr, png_infop info_ptr));
3317 PNG_EXPORT(263, png_byte, png_get_next_frame_blend_op,
3318 (png_structp png_ptr, png_infop info_ptr));
3319 PNG_EXPORT(264, png_byte, png_get_first_frame_is_hidden,
3320 (png_structp png_ptr, png_infop info_ptr));
3321 PNG_EXPORT(265, png_uint_32, png_set_first_frame_is_hidden,
3322 (png_structp png_ptr, png_infop info_ptr, png_byte is_hidden));
3324 #ifdef PNG_READ_APNG_SUPPORTED
3325 PNG_EXPORT(266, void, png_read_frame_head, (png_structp png_ptr,
3326 png_infop info_ptr));
3327 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
3328 PNG_EXPORT(267, void, png_set_progressive_frame_fn, (png_structp png_ptr,
3329 png_progressive_frame_ptr frame_info_fn,
3330 png_progressive_frame_ptr frame_end_fn));
3331 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
3332 #endif /* PNG_READ_APNG_SUPPORTED */
3334 #ifdef PNG_WRITE_APNG_SUPPORTED
3335 PNG_EXPORT(268, void, png_write_frame_head, (png_structp png_ptr,
3336 png_infop info_ptr, png_bytepp row_pointers,
3337 png_uint_32 width, png_uint_32 height,
3338 png_uint_32 x_offset, png_uint_32 y_offset,
3339 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
3340 png_byte blend_op));
3342 PNG_EXPORT(269, void, png_write_frame_tail, (png_structp png_ptr,
3343 png_infop info_ptr));
3344 #endif /* PNG_WRITE_APNG_SUPPORTED */
3345 #endif /* PNG_APNG_SUPPORTED */
3351 /* Read the whole image into memory at once. */
3352 #ifdef PNG_APNG_SUPPORTED
3353 PNG_EXPORT(270, void, png_read_image_with_pick_color, (png_structp png_ptr,
3355 PngPickColor *pickcolor));
3357 PNG_EXPORT(250, void, png_read_image_with_pick_color, (png_structp png_ptr,
3359 PngPickColor *pickcolor));
3363 /* Maintainer: Put new public prototypes here ^, in libpng.3, in project
3364 * defs, and in scripts/symbols.def.
3367 /* The last ordinal number (this is the *last* one already used; the next
3368 * one to use is one more than this.)
3370 #ifdef PNG_EXPORT_LAST_ORDINAL
3372 #ifdef PNG_APNG_SUPPORTED
3373 PNG_EXPORT_LAST_ORDINAL(270);
3375 PNG_EXPORT_LAST_ORDINAL(250);
3376 #endif /* PNG_APNG_SUPPORTED */
3378 #ifdef PNG_APNG_SUPPORTED
3379 PNG_EXPORT_LAST_ORDINAL(269);
3381 PNG_EXPORT_LAST_ORDINAL(249);
3382 #endif /* PNG_APNG_SUPPORTED */
3383 #endif /* __TIZEN__ */
3390 #endif /* PNG_VERSION_INFO_ONLY */
3391 /* Do not put anything past this line */