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Last change on this file since 1537 was 613, checked in by sam, 11 years ago

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File size: 116.2 KB

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1
2	/* png.h - header file for PNG reference library
3	*
4	* libpng version 1.4.3 - June 26, 2010
5	* Copyright (c) 1998-2010 Glenn Randers-Pehrson
6	* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7	* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8	*
9	* This code is released under the libpng license (See LICENSE, below)
10	*
11	* Authors and maintainers:
12	* libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
13	* libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
14	* libpng versions 0.97, January 1998, through 1.4.3 - June 26, 2010: Glenn
15	* See also "Contributing Authors", below.
16	*
17	* Note about libpng version numbers:
18	*
19	* Due to various miscommunications, unforeseen code incompatibilities
20	* and occasional factors outside the authors' control, version numbering
21	* on the library has not always been consistent and straightforward.
22	* The following table summarizes matters since version 0.89c, which was
23	* the first widely used release:
24	*
25	* source png.h png.h shared-lib
26	* version string int version
27	* ------- ------ ----- ----------
28	* 0.89c "1.0 beta 3" 0.89 89 1.0.89
29	* 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
30	* 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
31	* 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
32	* 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
33	* 0.97c 0.97 97 2.0.97
34	* 0.98 0.98 98 2.0.98
35	* 0.99 0.99 98 2.0.99
36	* 0.99a-m 0.99 99 2.0.99
37	* 1.00 1.00 100 2.1.0 [100 should be 10000]
38	* 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
39	* 1.0.1 png.h string is 10001 2.1.0
40	* 1.0.1a-e identical to the 10002 from here on, the shared library
41	* 1.0.2 source version) 10002 is 2.V where V is the source code
42	* 1.0.2a-b 10003 version, except as noted.
43	* 1.0.3 10003
44	* 1.0.3a-d 10004
45	* 1.0.4 10004
46	* 1.0.4a-f 10005
47	* 1.0.5 (+ 2 patches) 10005
48	* 1.0.5a-d 10006
49	* 1.0.5e-r 10100 (not source compatible)
50	* 1.0.5s-v 10006 (not binary compatible)
51	* 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
52	* 1.0.6d-f 10007 (still binary incompatible)
53	* 1.0.6g 10007
54	* 1.0.6h 10007 10.6h (testing xy.z so-numbering)
55	* 1.0.6i 10007 10.6i
56	* 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
57	* 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
58	* 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
59	* 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
60	* 1.0.7 1 10007 (still compatible)
61	* 1.0.8beta1-4 1 10008 2.1.0.8beta1-4
62	* 1.0.8rc1 1 10008 2.1.0.8rc1
63	* 1.0.8 1 10008 2.1.0.8
64	* 1.0.9beta1-6 1 10009 2.1.0.9beta1-6
65	* 1.0.9rc1 1 10009 2.1.0.9rc1
66	* 1.0.9beta7-10 1 10009 2.1.0.9beta7-10
67	* 1.0.9rc2 1 10009 2.1.0.9rc2
68	* 1.0.9 1 10009 2.1.0.9
69	* 1.0.10beta1 1 10010 2.1.0.10beta1
70	* 1.0.10rc1 1 10010 2.1.0.10rc1
71	* 1.0.10 1 10010 2.1.0.10
72	* 1.0.11beta1-3 1 10011 2.1.0.11beta1-3
73	* 1.0.11rc1 1 10011 2.1.0.11rc1
74	* 1.0.11 1 10011 2.1.0.11
75	* 1.0.12beta1-2 2 10012 2.1.0.12beta1-2
76	* 1.0.12rc1 2 10012 2.1.0.12rc1
77	* 1.0.12 2 10012 2.1.0.12
78	* 1.1.0a-f - 10100 2.1.1.0a-f (branch abandoned)
79	* 1.2.0beta1-2 2 10200 2.1.2.0beta1-2
80	* 1.2.0beta3-5 3 10200 3.1.2.0beta3-5
81	* 1.2.0rc1 3 10200 3.1.2.0rc1
82	* 1.2.0 3 10200 3.1.2.0
83	* 1.2.1beta1-4 3 10201 3.1.2.1beta1-4
84	* 1.2.1rc1-2 3 10201 3.1.2.1rc1-2
85	* 1.2.1 3 10201 3.1.2.1
86	* 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6
87	* 1.0.13beta1 10 10013 10.so.0.1.0.13beta1
88	* 1.0.13rc1 10 10013 10.so.0.1.0.13rc1
89	* 1.2.2rc1 12 10202 12.so.0.1.2.2rc1
90	* 1.0.13 10 10013 10.so.0.1.0.13
91	* 1.2.2 12 10202 12.so.0.1.2.2
92	* 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6
93	* 1.2.3 12 10203 12.so.0.1.2.3
94	* 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3
95	* 1.0.14rc1 13 10014 10.so.0.1.0.14rc1
96	* 1.2.4rc1 13 10204 12.so.0.1.2.4rc1
97	* 1.0.14 10 10014 10.so.0.1.0.14
98	* 1.2.4 13 10204 12.so.0.1.2.4
99	* 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2
100	* 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3
101	* 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3
102	* 1.0.15 10 10015 10.so.0.1.0.15
103	* 1.2.5 13 10205 12.so.0.1.2.5
104	* 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4
105	* 1.0.16 10 10016 10.so.0.1.0.16
106	* 1.2.6 13 10206 12.so.0.1.2.6
107	* 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2
108	* 1.0.17rc1 10 10017 12.so.0.1.0.17rc1
109	* 1.2.7rc1 13 10207 12.so.0.1.2.7rc1
110	* 1.0.17 10 10017 12.so.0.1.0.17
111	* 1.2.7 13 10207 12.so.0.1.2.7
112	* 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5
113	* 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5
114	* 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5
115	* 1.0.18 10 10018 12.so.0.1.0.18
116	* 1.2.8 13 10208 12.so.0.1.2.8
117	* 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3
118	* 1.2.9beta4-11 13 10209 12.so.0.9[.0]
119	* 1.2.9rc1 13 10209 12.so.0.9[.0]
120	* 1.2.9 13 10209 12.so.0.9[.0]
121	* 1.2.10beta1-7 13 10210 12.so.0.10[.0]
122	* 1.2.10rc1-2 13 10210 12.so.0.10[.0]
123	* 1.2.10 13 10210 12.so.0.10[.0]
124	* 1.4.0beta1-5 14 10400 14.so.0.0[.0]
125	* 1.2.11beta1-4 13 10211 12.so.0.11[.0]
126	* 1.4.0beta7-8 14 10400 14.so.0.0[.0]
127	* 1.2.11 13 10211 12.so.0.11[.0]
128	* 1.2.12 13 10212 12.so.0.12[.0]
129	* 1.4.0beta9-14 14 10400 14.so.0.0[.0]
130	* 1.2.13 13 10213 12.so.0.13[.0]
131	* 1.4.0beta15-36 14 10400 14.so.0.0[.0]
132	* 1.4.0beta37-87 14 10400 14.so.14.0[.0]
133	* 1.4.0rc01 14 10400 14.so.14.0[.0]
134	* 1.4.0beta88-109 14 10400 14.so.14.0[.0]
135	* 1.4.0rc02-08 14 10400 14.so.14.0[.0]
136	* 1.4.0 14 10400 14.so.14.0[.0]
137	* 1.4.1beta01-03 14 10401 14.so.14.1[.0]
138	* 1.4.1rc01 14 10401 14.so.14.1[.0]
139	* 1.4.1beta04-12 14 10401 14.so.14.1[.0]
140	* 1.4.1rc02-04 14 10401 14.so.14.1[.0]
141	* 1.4.1 14 10401 14.so.14.1[.0]
142	* 1.4.2beta01 14 10402 14.so.14.2[.0]
143	* 1.4.2rc02-06 14 10402 14.so.14.2[.0]
144	* 1.4.2 14 10402 14.so.14.2[.0]
145	* 1.4.3beta01-05 14 10403 14.so.14.3[.0]
146	* 1.4.3rc01-03 14 10403 14.so.14.3[.0]
147	* 1.4.3 14 10403 14.so.14.3[.0]
148	*
149	* Henceforth the source version will match the shared-library major
150	* and minor numbers; the shared-library major version number will be
151	* used for changes in backward compatibility, as it is intended. The
152	* PNG_LIBPNG_VER macro, which is not used within libpng but is available
153	* for applications, is an unsigned integer of the form xyyzz corresponding
154	* to the source version x.y.z (leading zeros in y and z). Beta versions
155	* were given the previous public release number plus a letter, until
156	* version 1.0.6j; from then on they were given the upcoming public
157	* release number plus "betaNN" or "rcN".
158	*
159	* Binary incompatibility exists only when applications make direct access
160	* to the info_ptr or png_ptr members through png.h, and the compiled
161	* application is loaded with a different version of the library.
162	*
163	* DLLNUM will change each time there are forward or backward changes
164	* in binary compatibility (e.g., when a new feature is added).
165	*
166	* See libpng.txt or libpng.3 for more information. The PNG specification
167	* is available as a W3C Recommendation and as an ISO Specification,
168	* <http://www.w3.org/TR/2003/REC-PNG-20031110/
169	*/
170
171	/*
172	* COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
173	*
174	* If you modify libpng you may insert additional notices immediately following
175	* this sentence.
176	*
177	* This code is released under the libpng license.
178	*
179	* libpng versions 1.2.6, August 15, 2004, through 1.4.3, June 26, 2010, are
180	* Copyright (c) 2004, 2006-2010 Glenn Randers-Pehrson, and are
181	* distributed according to the same disclaimer and license as libpng-1.2.5
182	* with the following individual added to the list of Contributing Authors:
183	*
184	* Cosmin Truta
185	*
186	* libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
187	* Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
188	* distributed according to the same disclaimer and license as libpng-1.0.6
189	* with the following individuals added to the list of Contributing Authors:
190	*
191	* Simon-Pierre Cadieux
192	* Eric S. Raymond
193	* Gilles Vollant
194	*
195	* and with the following additions to the disclaimer:
196	*
197	* There is no warranty against interference with your enjoyment of the
198	* library or against infringement. There is no warranty that our
199	* efforts or the library will fulfill any of your particular purposes
200	* or needs. This library is provided with all faults, and the entire
201	* risk of satisfactory quality, performance, accuracy, and effort is with
202	* the user.
203	*
204	* libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
205	* Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
206	* distributed according to the same disclaimer and license as libpng-0.96,
207	* with the following individuals added to the list of Contributing Authors:
208	*
209	* Tom Lane
210	* Glenn Randers-Pehrson
211	* Willem van Schaik
212	*
213	* libpng versions 0.89, June 1996, through 0.96, May 1997, are
214	* Copyright (c) 1996, 1997 Andreas Dilger
215	* Distributed according to the same disclaimer and license as libpng-0.88,
216	* with the following individuals added to the list of Contributing Authors:
217	*
218	* John Bowler
219	* Kevin Bracey
220	* Sam Bushell
221	* Magnus Holmgren
222	* Greg Roelofs
223	* Tom Tanner
224	*
225	* libpng versions 0.5, May 1995, through 0.88, January 1996, are
226	* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
227	*
228	* For the purposes of this copyright and license, "Contributing Authors"
229	* is defined as the following set of individuals:
230	*
231	* Andreas Dilger
232	* Dave Martindale
233	* Guy Eric Schalnat
234	* Paul Schmidt
235	* Tim Wegner
236	*
237	* The PNG Reference Library is supplied "AS IS". The Contributing Authors
238	* and Group 42, Inc. disclaim all warranties, expressed or implied,
239	* including, without limitation, the warranties of merchantability and of
240	* fitness for any purpose. The Contributing Authors and Group 42, Inc.
241	* assume no liability for direct, indirect, incidental, special, exemplary,
242	* or consequential damages, which may result from the use of the PNG
243	* Reference Library, even if advised of the possibility of such damage.
244	*
245	* Permission is hereby granted to use, copy, modify, and distribute this
246	* source code, or portions hereof, for any purpose, without fee, subject
247	* to the following restrictions:
248	*
249	* 1. The origin of this source code must not be misrepresented.
250	*
251	* 2. Altered versions must be plainly marked as such and
252	* must not be misrepresented as being the original source.
253	*
254	* 3. This Copyright notice may not be removed or altered from
255	* any source or altered source distribution.
256	*
257	* The Contributing Authors and Group 42, Inc. specifically permit, without
258	* fee, and encourage the use of this source code as a component to
259	* supporting the PNG file format in commercial products. If you use this
260	* source code in a product, acknowledgment is not required but would be
261	* appreciated.
262	*/
263
264	/*
265	* A "png_get_copyright" function is available, for convenient use in "about"
266	* boxes and the like:
267	*
268	* printf("%s",png_get_copyright(NULL));
269	*
270	* Also, the PNG logo (in PNG format, of course) is supplied in the
271	* files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
272	*/
273
274	/*
275	* Libpng is OSI Certified Open Source Software. OSI Certified is a
276	* certification mark of the Open Source Initiative.
277	*/
278
279	/*
280	* The contributing authors would like to thank all those who helped
281	* with testing, bug fixes, and patience. This wouldn't have been
282	* possible without all of you.
283	*
284	* Thanks to Frank J. T. Wojcik for helping with the documentation.
285	*/
286
287	/*
288	* Y2K compliance in libpng:
289	* =========================
290	*
291	* June 26, 2010
292	*
293	* Since the PNG Development group is an ad-hoc body, we can't make
294	* an official declaration.
295	*
296	* This is your unofficial assurance that libpng from version 0.71 and
297	* upward through 1.4.3 are Y2K compliant. It is my belief that earlier
298	* versions were also Y2K compliant.
299	*
300	* Libpng only has three year fields. One is a 2-byte unsigned integer
301	* that will hold years up to 65535. The other two hold the date in text
302	* format, and will hold years up to 9999.
303	*
304	* The integer is
305	* "png_uint_16 year" in png_time_struct.
306	*
307	* The strings are
308	* "png_charp time_buffer" in png_struct and
309	* "near_time_buffer", which is a local character string in png.c.
310	*
311	* There are seven time-related functions:
312	* png.c: png_convert_to_rfc_1123() in png.c
313	* (formerly png_convert_to_rfc_1152() in error)
314	* png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
315	* png_convert_from_time_t() in pngwrite.c
316	* png_get_tIME() in pngget.c
317	* png_handle_tIME() in pngrutil.c, called in pngread.c
318	* png_set_tIME() in pngset.c
319	* png_write_tIME() in pngwutil.c, called in pngwrite.c
320	*
321	* All handle dates properly in a Y2K environment. The
322	* png_convert_from_time_t() function calls gmtime() to convert from system
323	* clock time, which returns (year - 1900), which we properly convert to
324	* the full 4-digit year. There is a possibility that applications using
325	* libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
326	* function, or that they are incorrectly passing only a 2-digit year
327	* instead of "year - 1900" into the png_convert_from_struct_tm() function,
328	* but this is not under our control. The libpng documentation has always
329	* stated that it works with 4-digit years, and the APIs have been
330	* documented as such.
331	*
332	* The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
333	* integer to hold the year, and can hold years as large as 65535.
334	*
335	* zlib, upon which libpng depends, is also Y2K compliant. It contains
336	* no date-related code.
337	*
338	* Glenn Randers-Pehrson
339	* libpng maintainer
340	* PNG Development Group
341	*/
342
343	#ifndef PNG_H
344	#define PNG_H
345
346	/* This is not the place to learn how to use libpng. The file libpng.txt
347	* describes how to use libpng, and the file example.c summarizes it
348	* with some code on which to build. This file is useful for looking
349	* at the actual function definitions and structure components.
350	*/
351
352	/* Version information for png.h - this should match the version in png.c */
353	#define PNG_LIBPNG_VER_STRING "1.4.3"
354	#define PNG_HEADER_VERSION_STRING \
355	" libpng version 1.4.3 - June 26, 2010\n"
356
357	#define PNG_LIBPNG_VER_SONUM 14
358	#define PNG_LIBPNG_VER_DLLNUM 14
359
360	/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
361	#define PNG_LIBPNG_VER_MAJOR 1
362	#define PNG_LIBPNG_VER_MINOR 4
363	#define PNG_LIBPNG_VER_RELEASE 3
364	/* This should match the numeric part of the final component of
365	* PNG_LIBPNG_VER_STRING, omitting any leading zero:
366	*/
367
368	#define PNG_LIBPNG_VER_BUILD 0
369
370	/* Release Status */
371	#define PNG_LIBPNG_BUILD_ALPHA 1
372	#define PNG_LIBPNG_BUILD_BETA 2
373	#define PNG_LIBPNG_BUILD_RC 3
374	#define PNG_LIBPNG_BUILD_STABLE 4
375	#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
376
377	/* Release-Specific Flags */
378	#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
379	PNG_LIBPNG_BUILD_STABLE only */
380	#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
381	PNG_LIBPNG_BUILD_SPECIAL */
382	#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
383	PNG_LIBPNG_BUILD_PRIVATE */
384
385	#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
386
387	/* Careful here. At one time, Guy wanted to use 082, but that would be octal.
388	* We must not include leading zeros.
389	* Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
390	* version 1.0.0 was mis-numbered 100 instead of 10000). From
391	* version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
392	*/
393	#define PNG_LIBPNG_VER 10403 /* 1.4.3 */
394
395	#ifndef PNG_VERSION_INFO_ONLY
396	/* Include the compression library's header */
397	#include "zlib.h"
398	#endif
399
400	/* Include all user configurable info, including optional assembler routines */
401	#include "pngconf.h"
402
403	/*
404	* Added at libpng-1.2.8
405	*
406	* Ref MSDN: Private as priority over Special
407	* VS_FF_PRIVATEBUILD File was not built using standard release
408	* procedures. If this value is given, the StringFileInfo block must
409	* contain a PrivateBuild string.
410	*
411	* VS_FF_SPECIALBUILD File was built by the original company using
412	* standard release procedures but is a variation of the standard
413	* file of the same version number. If this value is given, the
414	* StringFileInfo block must contain a SpecialBuild string.
415	*/
416
417	#ifdef PNG_USER_PRIVATEBUILD
418	# define PNG_LIBPNG_BUILD_TYPE \
419	(PNG_LIBPNG_BUILD_BASE_TYPE \| PNG_LIBPNG_BUILD_PRIVATE)
420	#else
421	# ifdef PNG_LIBPNG_SPECIALBUILD
422	# define PNG_LIBPNG_BUILD_TYPE \
423	(PNG_LIBPNG_BUILD_BASE_TYPE \| PNG_LIBPNG_BUILD_SPECIAL)
424	# else
425	# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
426	# endif
427	#endif
428
429	#ifndef PNG_VERSION_INFO_ONLY
430
431	/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
432	#ifdef __cplusplus
433	extern "C" {
434	#endif /* __cplusplus */
435
436	/* This file is arranged in several sections. The first section contains
437	* structure and type definitions. The second section contains the external
438	* library functions, while the third has the internal library functions,
439	* which applications aren't expected to use directly.
440	*/
441
442	/* Variables declared in png.c - only it needs to define PNG_NO_EXTERN */
443	#if !defined(PNG_NO_EXTERN) \|\| defined(PNG_ALWAYS_EXTERN)
444	/* Version information for C files, stored in png.c. This had better match
445	* the version above.
446	*/
447	#define png_libpng_ver png_get_header_ver(NULL)
448
449	#endif /* PNG_NO_EXTERN */
450
451	/* Three color definitions. The order of the red, green, and blue, (and the
452	* exact size) is not important, although the size of the fields need to
453	* be png_byte or png_uint_16 (as defined below).
454	*/
455	typedef struct png_color_struct
456	{
457	png_byte red;
458	png_byte green;
459	png_byte blue;
460	} png_color;
461	typedef png_color FAR * png_colorp;
462	typedef png_color FAR * FAR * png_colorpp;
463
464	typedef struct png_color_16_struct
465	{
466	png_byte index; /* used for palette files */
467	png_uint_16 red; /* for use in red green blue files */
468	png_uint_16 green;
469	png_uint_16 blue;
470	png_uint_16 gray; /* for use in grayscale files */
471	} png_color_16;
472	typedef png_color_16 FAR * png_color_16p;
473	typedef png_color_16 FAR * FAR * png_color_16pp;
474
475	typedef struct png_color_8_struct
476	{
477	png_byte red; /* for use in red green blue files */
478	png_byte green;
479	png_byte blue;
480	png_byte gray; /* for use in grayscale files */
481	png_byte alpha; /* for alpha channel files */
482	} png_color_8;
483	typedef png_color_8 FAR * png_color_8p;
484	typedef png_color_8 FAR * FAR * png_color_8pp;
485
486	/*
487	* The following two structures are used for the in-core representation
488	* of sPLT chunks.
489	*/
490	typedef struct png_sPLT_entry_struct
491	{
492	png_uint_16 red;
493	png_uint_16 green;
494	png_uint_16 blue;
495	png_uint_16 alpha;
496	png_uint_16 frequency;
497	} png_sPLT_entry;
498	typedef png_sPLT_entry FAR * png_sPLT_entryp;
499	typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;
500
501	/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
502	* occupy the LSB of their respective members, and the MSB of each member
503	* is zero-filled. The frequency member always occupies the full 16 bits.
504	*/
505
506	typedef struct png_sPLT_struct
507	{
508	png_charp name; /* palette name */
509	png_byte depth; /* depth of palette samples */
510	png_sPLT_entryp entries; /* palette entries */
511	png_int_32 nentries; /* number of palette entries */
512	} png_sPLT_t;
513	typedef png_sPLT_t FAR * png_sPLT_tp;
514	typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;
515
516	#ifdef PNG_TEXT_SUPPORTED
517	/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
518	* and whether that contents is compressed or not. The "key" field
519	* points to a regular zero-terminated C string. The "text", "lang", and
520	* "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
521	* However, the * structure returned by png_get_text() will always contain
522	* regular zero-terminated C strings (possibly empty), never NULL pointers,
523	* so they can be safely used in printf() and other string-handling functions.
524	*/
525	typedef struct png_text_struct
526	{
527	int compression; /* compression value:
528	-1: tEXt, none
529	0: zTXt, deflate
530	1: iTXt, none
531	2: iTXt, deflate */
532	png_charp key; /* keyword, 1-79 character description of "text" */
533	png_charp text; /* comment, may be an empty string (ie "")
534	or a NULL pointer */
535	png_size_t text_length; /* length of the text string */
536	#ifdef PNG_iTXt_SUPPORTED
537	png_size_t itxt_length; /* length of the itxt string */
538	png_charp lang; /* language code, 0-79 characters
539	or a NULL pointer */
540	png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
541	chars or a NULL pointer */
542	#endif
543	} png_text;
544	typedef png_text FAR * png_textp;
545	typedef png_text FAR * FAR * png_textpp;
546	#endif
547
548	/* Supported compression types for text in PNG files (tEXt, and zTXt).
549	* The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
550	#define PNG_TEXT_COMPRESSION_NONE_WR -3
551	#define PNG_TEXT_COMPRESSION_zTXt_WR -2
552	#define PNG_TEXT_COMPRESSION_NONE -1
553	#define PNG_TEXT_COMPRESSION_zTXt 0
554	#define PNG_ITXT_COMPRESSION_NONE 1
555	#define PNG_ITXT_COMPRESSION_zTXt 2
556	#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
557
558	/* png_time is a way to hold the time in an machine independent way.
559	* Two conversions are provided, both from time_t and struct tm. There
560	* is no portable way to convert to either of these structures, as far
561	* as I know. If you know of a portable way, send it to me. As a side
562	* note - PNG has always been Year 2000 compliant!
563	*/
564	typedef struct png_time_struct
565	{
566	png_uint_16 year; /* full year, as in, 1995 */
567	png_byte month; /* month of year, 1 - 12 */
568	png_byte day; /* day of month, 1 - 31 */
569	png_byte hour; /* hour of day, 0 - 23 */
570	png_byte minute; /* minute of hour, 0 - 59 */
571	png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
572	} png_time;
573	typedef png_time FAR * png_timep;
574	typedef png_time FAR * FAR * png_timepp;
575
576	#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) \|\| \
577	defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
578	/* png_unknown_chunk is a structure to hold queued chunks for which there is
579	* no specific support. The idea is that we can use this to queue
580	* up private chunks for output even though the library doesn't actually
581	* know about their semantics.
582	*/
583	typedef struct png_unknown_chunk_t
584	{
585	png_byte name[5];
586	png_byte *data;
587	png_size_t size;
588
589	/* libpng-using applications should NOT directly modify this byte. */
590	png_byte location; /* mode of operation at read time */
591	}
592	png_unknown_chunk;
593	typedef png_unknown_chunk FAR * png_unknown_chunkp;
594	typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
595	#endif
596
597	/* png_info is a structure that holds the information in a PNG file so
598	* that the application can find out the characteristics of the image.
599	* If you are reading the file, this structure will tell you what is
600	* in the PNG file. If you are writing the file, fill in the information
601	* you want to put into the PNG file, then call png_write_info().
602	* The names chosen should be very close to the PNG specification, so
603	* consult that document for information about the meaning of each field.
604	*
605	* With libpng < 0.95, it was only possible to directly set and read the
606	* the values in the png_info_struct, which meant that the contents and
607	* order of the values had to remain fixed. With libpng 0.95 and later,
608	* however, there are now functions that abstract the contents of
609	* png_info_struct from the application, so this makes it easier to use
610	* libpng with dynamic libraries, and even makes it possible to use
611	* libraries that don't have all of the libpng ancillary chunk-handing
612	* functionality.
613	*
614	* In any case, the order of the parameters in png_info_struct should NOT
615	* be changed for as long as possible to keep compatibility with applications
616	* that use the old direct-access method with png_info_struct.
617	*
618	* The following members may have allocated storage attached that should be
619	* cleaned up before the structure is discarded: palette, trans, text,
620	* pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
621	* splt_palettes, scal_unit, row_pointers, and unknowns. By default, these
622	* are automatically freed when the info structure is deallocated, if they were
623	* allocated internally by libpng. This behavior can be changed by means
624	* of the png_data_freer() function.
625	*
626	* More allocation details: all the chunk-reading functions that
627	* change these members go through the corresponding png_set_*
628	* functions. A function to clear these members is available: see
629	* png_free_data(). The png_set_* functions do not depend on being
630	* able to point info structure members to any of the storage they are
631	* passed (they make their own copies), EXCEPT that the png_set_text
632	* functions use the same storage passed to them in the text_ptr or
633	* itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
634	* functions do not make their own copies.
635	*/
636	typedef struct png_info_struct
637	{
638	/* the following are necessary for every PNG file */
639	png_uint_32 width PNG_DEPSTRUCT; /* width of image in pixels (from IHDR) */
640	png_uint_32 height PNG_DEPSTRUCT; /* height of image in pixels (from IHDR) */
641	png_uint_32 valid PNG_DEPSTRUCT; /* valid chunk data (see PNG_INFO_
642	below) */
643	png_size_t rowbytes PNG_DEPSTRUCT; /* bytes needed to hold an untransformed
644	row */
645	png_colorp palette PNG_DEPSTRUCT; /* array of color values
646	(valid & PNG_INFO_PLTE) */
647	png_uint_16 num_palette PNG_DEPSTRUCT; /* number of color entries in
648	"palette" (PLTE) */
649	png_uint_16 num_trans PNG_DEPSTRUCT; /* number of transparent palette
650	color (tRNS) */
651	png_byte bit_depth PNG_DEPSTRUCT; /* 1, 2, 4, 8, or 16 bits/channel
652	(from IHDR) */
653	png_byte color_type PNG_DEPSTRUCT; /* see PNG_COLOR_TYPE_ below
654	(from IHDR) */
655	/* The following three should have been named _method not _type */
656	png_byte compression_type PNG_DEPSTRUCT; /* must be
657	PNG_COMPRESSION_TYPE_BASE (IHDR) */
658	png_byte filter_type PNG_DEPSTRUCT; /* must be PNG_FILTER_TYPE_BASE
659	(from IHDR) */
660	png_byte interlace_type PNG_DEPSTRUCT; /* One of PNG_INTERLACE_NONE,
661	PNG_INTERLACE_ADAM7 */
662
663	/* The following is informational only on read, and not used on writes. */
664	png_byte channels PNG_DEPSTRUCT; /* number of data channels per
665	pixel (1, 2, 3, 4) */
666	png_byte pixel_depth PNG_DEPSTRUCT; /* number of bits per pixel */
667	png_byte spare_byte PNG_DEPSTRUCT; /* to align the data, and for
668	future use */
669	png_byte signature[8] PNG_DEPSTRUCT; /* magic bytes read by libpng
670	from start of file */
671
672	/* The rest of the data is optional. If you are reading, check the
673	* valid field to see if the information in these are valid. If you
674	* are writing, set the valid field to those chunks you want written,
675	* and initialize the appropriate fields below.
676	*/
677
678	#if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
679	/* The gAMA chunk describes the gamma characteristics of the system
680	* on which the image was created, normally in the range [1.0, 2.5].
681	* Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
682	*/
683	float gamma PNG_DEPSTRUCT; /* gamma value of image,
684	if (valid & PNG_INFO_gAMA) */
685	#endif
686
687	#ifdef PNG_sRGB_SUPPORTED
688	/* GR-P, 0.96a */
689	/* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
690	png_byte srgb_intent PNG_DEPSTRUCT; /* sRGB rendering intent
691	[0, 1, 2, or 3] */
692	#endif
693
694	#ifdef PNG_TEXT_SUPPORTED
695	/* The tEXt, and zTXt chunks contain human-readable textual data in
696	* uncompressed, compressed, and optionally compressed forms, respectively.
697	* The data in "text" is an array of pointers to uncompressed,
698	* null-terminated C strings. Each chunk has a keyword that describes the
699	* textual data contained in that chunk. Keywords are not required to be
700	* unique, and the text string may be empty. Any number of text chunks may
701	* be in an image.
702	*/
703	int num_text PNG_DEPSTRUCT; /* number of comments read/to write */
704	int max_text PNG_DEPSTRUCT; /* current size of text array */
705	png_textp text PNG_DEPSTRUCT; /* array of comments read/to write */
706	#endif /* PNG_TEXT_SUPPORTED */
707
708	#ifdef PNG_tIME_SUPPORTED
709	/* The tIME chunk holds the last time the displayed image data was
710	* modified. See the png_time struct for the contents of this struct.
711	*/
712	png_time mod_time PNG_DEPSTRUCT;
713	#endif
714
715	#ifdef PNG_sBIT_SUPPORTED
716	/* The sBIT chunk specifies the number of significant high-order bits
717	* in the pixel data. Values are in the range [1, bit_depth], and are
718	* only specified for the channels in the pixel data. The contents of
719	* the low-order bits is not specified. Data is valid if
720	* (valid & PNG_INFO_sBIT) is non-zero.
721	*/
722	png_color_8 sig_bit PNG_DEPSTRUCT; /* significant bits in color channels */
723	#endif
724
725	#if defined(PNG_tRNS_SUPPORTED) \|\| defined(PNG_READ_EXPAND_SUPPORTED) \|\| \
726	defined(PNG_READ_BACKGROUND_SUPPORTED)
727	/* The tRNS chunk supplies transparency data for paletted images and
728	* other image types that don't need a full alpha channel. There are
729	* "num_trans" transparency values for a paletted image, stored in the
730	* same order as the palette colors, starting from index 0. Values
731	* for the data are in the range [0, 255], ranging from fully transparent
732	* to fully opaque, respectively. For non-paletted images, there is a
733	* single color specified that should be treated as fully transparent.
734	* Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
735	*/
736	png_bytep trans_alpha PNG_DEPSTRUCT; /* alpha values for paletted
737	image */
738	png_color_16 trans_color PNG_DEPSTRUCT; /* transparent color for
739	non-palette image */
740	#endif
741
742	#if defined(PNG_bKGD_SUPPORTED) \|\| defined(PNG_READ_BACKGROUND_SUPPORTED)
743	/* The bKGD chunk gives the suggested image background color if the
744	* display program does not have its own background color and the image
745	* is needs to composited onto a background before display. The colors
746	* in "background" are normally in the same color space/depth as the
747	* pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
748	*/
749	png_color_16 background PNG_DEPSTRUCT;
750	#endif
751
752	#ifdef PNG_oFFs_SUPPORTED
753	/* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
754	* and downwards from the top-left corner of the display, page, or other
755	* application-specific co-ordinate space. See the PNG_OFFSET_ defines
756	* below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero.
757	*/
758	png_int_32 x_offset PNG_DEPSTRUCT; /* x offset on page */
759	png_int_32 y_offset PNG_DEPSTRUCT; /* y offset on page */
760	png_byte offset_unit_type PNG_DEPSTRUCT; /* offset units type */
761	#endif
762
763	#ifdef PNG_pHYs_SUPPORTED
764	/* The pHYs chunk gives the physical pixel density of the image for
765	* display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
766	* defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
767	*/
768	png_uint_32 x_pixels_per_unit PNG_DEPSTRUCT; /* horizontal pixel density */
769	png_uint_32 y_pixels_per_unit PNG_DEPSTRUCT; /* vertical pixel density */
770	png_byte phys_unit_type PNG_DEPSTRUCT; /* resolution type (see
771	PNG_RESOLUTION_ below) */
772	#endif
773
774	#ifdef PNG_hIST_SUPPORTED
775	/* The hIST chunk contains the relative frequency or importance of the
776	* various palette entries, so that a viewer can intelligently select a
777	* reduced-color palette, if required. Data is an array of "num_palette"
778	* values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
779	* is non-zero.
780	*/
781	png_uint_16p hist PNG_DEPSTRUCT;
782	#endif
783
784	#ifdef PNG_cHRM_SUPPORTED
785	/* The cHRM chunk describes the CIE color characteristics of the monitor
786	* on which the PNG was created. This data allows the viewer to do gamut
787	* mapping of the input image to ensure that the viewer sees the same
788	* colors in the image as the creator. Values are in the range
789	* [0.0, 0.8]. Data valid if (valid & PNG_INFO_cHRM) non-zero.
790	*/
791	#ifdef PNG_FLOATING_POINT_SUPPORTED
792	float x_white PNG_DEPSTRUCT;
793	float y_white PNG_DEPSTRUCT;
794	float x_red PNG_DEPSTRUCT;
795	float y_red PNG_DEPSTRUCT;
796	float x_green PNG_DEPSTRUCT;
797	float y_green PNG_DEPSTRUCT;
798	float x_blue PNG_DEPSTRUCT;
799	float y_blue PNG_DEPSTRUCT;
800	#endif
801	#endif
802
803	#ifdef PNG_pCAL_SUPPORTED
804	/* The pCAL chunk describes a transformation between the stored pixel
805	* values and original physical data values used to create the image.
806	* The integer range [0, 2^bit_depth - 1] maps to the floating-point
807	* range given by [pcal_X0, pcal_X1], and are further transformed by a
808	* (possibly non-linear) transformation function given by "pcal_type"
809	* and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_
810	* defines below, and the PNG-Group's PNG extensions document for a
811	* complete description of the transformations and how they should be
812	* implemented, and for a description of the ASCII parameter strings.
813	* Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
814	*/
815	png_charp pcal_purpose PNG_DEPSTRUCT; /* pCAL chunk description string */
816	png_int_32 pcal_X0 PNG_DEPSTRUCT; /* minimum value */
817	png_int_32 pcal_X1 PNG_DEPSTRUCT; /* maximum value */
818	png_charp pcal_units PNG_DEPSTRUCT; /* Latin-1 string giving physical
819	units */
820	png_charpp pcal_params PNG_DEPSTRUCT; /* ASCII strings containing
821	parameter values */
822	png_byte pcal_type PNG_DEPSTRUCT; /* equation type
823	(see PNG_EQUATION_ below) */
824	png_byte pcal_nparams PNG_DEPSTRUCT; /* number of parameters given
825	in pcal_params */
826	#endif
827
828	/* New members added in libpng-1.0.6 */
829	png_uint_32 free_me PNG_DEPSTRUCT; /* flags items libpng is
830	responsible for freeing */
831
832	#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) \|\| \
833	defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
834	/* Storage for unknown chunks that the library doesn't recognize. */
835	png_unknown_chunkp unknown_chunks PNG_DEPSTRUCT;
836	png_size_t unknown_chunks_num PNG_DEPSTRUCT;
837	#endif
838
839	#ifdef PNG_iCCP_SUPPORTED
840	/* iCCP chunk data. */
841	png_charp iccp_name PNG_DEPSTRUCT; /* profile name */
842	png_charp iccp_profile PNG_DEPSTRUCT; /* International Color Consortium
843	profile data */
844	/* Note to maintainer: should be png_bytep */
845	png_uint_32 iccp_proflen PNG_DEPSTRUCT; /* ICC profile data length */
846	png_byte iccp_compression PNG_DEPSTRUCT; /* Always zero */
847	#endif
848
849	#ifdef PNG_sPLT_SUPPORTED
850	/* Data on sPLT chunks (there may be more than one). */
851	png_sPLT_tp splt_palettes PNG_DEPSTRUCT;
852	png_uint_32 splt_palettes_num PNG_DEPSTRUCT;
853	#endif
854
855	#ifdef PNG_sCAL_SUPPORTED
856	/* The sCAL chunk describes the actual physical dimensions of the
857	* subject matter of the graphic. The chunk contains a unit specification
858	* a byte value, and two ASCII strings representing floating-point
859	* values. The values are width and height corresponsing to one pixel
860	* in the image. This external representation is converted to double
861	* here. Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.
862	*/
863	png_byte scal_unit PNG_DEPSTRUCT; /* unit of physical scale */
864	#ifdef PNG_FLOATING_POINT_SUPPORTED
865	double scal_pixel_width PNG_DEPSTRUCT; /* width of one pixel */
866	double scal_pixel_height PNG_DEPSTRUCT; /* height of one pixel */
867	#endif
868	#ifdef PNG_FIXED_POINT_SUPPORTED
869	png_charp scal_s_width PNG_DEPSTRUCT; /* string containing height */
870	png_charp scal_s_height PNG_DEPSTRUCT; /* string containing width */
871	#endif
872	#endif
873
874	#ifdef PNG_INFO_IMAGE_SUPPORTED
875	/* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
876	non-zero */
877	/* Data valid if (valid & PNG_INFO_IDAT) non-zero */
878	png_bytepp row_pointers PNG_DEPSTRUCT; /* the image bits */
879	#endif
880
881	#if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)
882	png_fixed_point int_gamma PNG_DEPSTRUCT; /* gamma of image,
883	if (valid & PNG_INFO_gAMA) */
884	#endif
885
886	#if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)
887	png_fixed_point int_x_white PNG_DEPSTRUCT;
888	png_fixed_point int_y_white PNG_DEPSTRUCT;
889	png_fixed_point int_x_red PNG_DEPSTRUCT;
890	png_fixed_point int_y_red PNG_DEPSTRUCT;
891	png_fixed_point int_x_green PNG_DEPSTRUCT;
892	png_fixed_point int_y_green PNG_DEPSTRUCT;
893	png_fixed_point int_x_blue PNG_DEPSTRUCT;
894	png_fixed_point int_y_blue PNG_DEPSTRUCT;
895	#endif
896
897	} png_info;
898
899	typedef png_info FAR * png_infop;
900	typedef png_info FAR * FAR * png_infopp;
901
902	/* Maximum positive integer used in PNG is (2^31)-1 */
903	#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
904	#define PNG_UINT_32_MAX ((png_uint_32)(-1))
905	#define PNG_SIZE_MAX ((png_size_t)(-1))
906
907	/* These describe the color_type field in png_info. */
908	/* color type masks */
909	#define PNG_COLOR_MASK_PALETTE 1
910	#define PNG_COLOR_MASK_COLOR 2
911	#define PNG_COLOR_MASK_ALPHA 4
912
913	/* color types. Note that not all combinations are legal */
914	#define PNG_COLOR_TYPE_GRAY 0
915	#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR \| PNG_COLOR_MASK_PALETTE)
916	#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
917	#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR \| PNG_COLOR_MASK_ALPHA)
918	#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
919	/* aliases */
920	#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
921	#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
922
923	/* This is for compression type. PNG 1.0-1.2 only define the single type. */
924	#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
925	#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
926
927	/* This is for filter type. PNG 1.0-1.2 only define the single type. */
928	#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
929	#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
930	#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
931
932	/* These are for the interlacing type. These values should NOT be changed. */
933	#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
934	#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
935	#define PNG_INTERLACE_LAST 2 /* Not a valid value */
936
937	/* These are for the oFFs chunk. These values should NOT be changed. */
938	#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
939	#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
940	#define PNG_OFFSET_LAST 2 /* Not a valid value */
941
942	/* These are for the pCAL chunk. These values should NOT be changed. */
943	#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
944	#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
945	#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
946	#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
947	#define PNG_EQUATION_LAST 4 /* Not a valid value */
948
949	/* These are for the sCAL chunk. These values should NOT be changed. */
950	#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
951	#define PNG_SCALE_METER 1 /* meters per pixel */
952	#define PNG_SCALE_RADIAN 2 /* radians per pixel */
953	#define PNG_SCALE_LAST 3 /* Not a valid value */
954
955	/* These are for the pHYs chunk. These values should NOT be changed. */
956	#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
957	#define PNG_RESOLUTION_METER 1 /* pixels/meter */
958	#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
959
960	/* These are for the sRGB chunk. These values should NOT be changed. */
961	#define PNG_sRGB_INTENT_PERCEPTUAL 0
962	#define PNG_sRGB_INTENT_RELATIVE 1
963	#define PNG_sRGB_INTENT_SATURATION 2
964	#define PNG_sRGB_INTENT_ABSOLUTE 3
965	#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
966
967	/* This is for text chunks */
968	#define PNG_KEYWORD_MAX_LENGTH 79
969
970	/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
971	#define PNG_MAX_PALETTE_LENGTH 256
972
973	/* These determine if an ancillary chunk's data has been successfully read
974	* from the PNG header, or if the application has filled in the corresponding
975	* data in the info_struct to be written into the output file. The values
976	* of the PNG_INFO_<chunk> defines should NOT be changed.
977	*/
978	#define PNG_INFO_gAMA 0x0001
979	#define PNG_INFO_sBIT 0x0002
980	#define PNG_INFO_cHRM 0x0004
981	#define PNG_INFO_PLTE 0x0008
982	#define PNG_INFO_tRNS 0x0010
983	#define PNG_INFO_bKGD 0x0020
984	#define PNG_INFO_hIST 0x0040
985	#define PNG_INFO_pHYs 0x0080
986	#define PNG_INFO_oFFs 0x0100
987	#define PNG_INFO_tIME 0x0200
988	#define PNG_INFO_pCAL 0x0400
989	#define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
990	#define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
991	#define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
992	#define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
993	#define PNG_INFO_IDAT 0x8000L /* ESR, 1.0.6 */
994
995	/* This is used for the transformation routines, as some of them
996	* change these values for the row. It also should enable using
997	* the routines for other purposes.
998	*/
999	typedef struct png_row_info_struct
1000	{
1001	png_uint_32 width; /* width of row */
1002	png_size_t rowbytes; /* number of bytes in row */
1003	png_byte color_type; /* color type of row */
1004	png_byte bit_depth; /* bit depth of row */
1005	png_byte channels; /* number of channels (1, 2, 3, or 4) */
1006	png_byte pixel_depth; /* bits per pixel (depth * channels) */
1007	} png_row_info;
1008
1009	typedef png_row_info FAR * png_row_infop;
1010	typedef png_row_info FAR * FAR * png_row_infopp;
1011
1012	/* These are the function types for the I/O functions and for the functions
1013	* that allow the user to override the default I/O functions with his or her
1014	* own. The png_error_ptr type should match that of user-supplied warning
1015	* and error functions, while the png_rw_ptr type should match that of the
1016	* user read/write data functions.
1017	*/
1018	typedef struct png_struct_def png_struct;
1019	typedef png_struct FAR * png_structp;
1020
1021	typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp));
1022	typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t));
1023	typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp));
1024	typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32,
1025	int));
1026	typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,
1027	int));
1028
1029	#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1030	typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp,
1031	png_infop));
1032	typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop));
1033	typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep,
1034	png_uint_32, int));
1035	#endif
1036
1037	#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) \|\| \
1038	defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
1039	typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,
1040	png_row_infop, png_bytep));
1041	#endif
1042
1043	#ifdef PNG_USER_CHUNKS_SUPPORTED
1044	typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp,
1045	png_unknown_chunkp));
1046	#endif
1047	#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
1048	typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
1049	#endif
1050	#ifdef PNG_SETJMP_SUPPORTED
1051	/* This must match the function definition in <setjmp.h>, and the
1052	* application must include this before png.h to obtain the definition
1053	* of jmp_buf.
1054	*/
1055	typedef void (PNGAPI *png_longjmp_ptr) PNGARG((jmp_buf, int));
1056	#endif
1057
1058	/* Transform masks for the high-level interface */
1059	#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
1060	#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
1061	#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
1062	#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
1063	#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
1064	#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
1065	#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
1066	#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
1067	#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
1068	#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
1069	#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
1070	#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
1071	#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
1072	/* Added to libpng-1.2.34 */
1073	#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
1074	#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
1075	/* Added to libpng-1.4.0 */
1076	#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
1077
1078	/* Flags for MNG supported features */
1079	#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
1080	#define PNG_FLAG_MNG_FILTER_64 0x04
1081	#define PNG_ALL_MNG_FEATURES 0x05
1082
1083	typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_alloc_size_t));
1084	typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));
1085
1086	/* The structure that holds the information to read and write PNG files.
1087	* The only people who need to care about what is inside of this are the
1088	* people who will be modifying the library for their own special needs.
1089	* It should NOT be accessed directly by an application, except to store
1090	* the jmp_buf.
1091	*/
1092
1093	struct png_struct_def
1094	{
1095	#ifdef PNG_SETJMP_SUPPORTED
1096	jmp_buf jmpbuf PNG_DEPSTRUCT; /* used in png_error */
1097	png_longjmp_ptr longjmp_fn PNG_DEPSTRUCT;/* setjmp non-local goto
1098	function. */
1099	#endif
1100	png_error_ptr error_fn PNG_DEPSTRUCT; /* function for printing
1101	errors and aborting */
1102	png_error_ptr warning_fn PNG_DEPSTRUCT; /* function for printing
1103	warnings */
1104	png_voidp error_ptr PNG_DEPSTRUCT; /* user supplied struct for
1105	error functions */
1106	png_rw_ptr write_data_fn PNG_DEPSTRUCT; /* function for writing
1107	output data */
1108	png_rw_ptr read_data_fn PNG_DEPSTRUCT; /* function for reading
1109	input data */
1110	png_voidp io_ptr PNG_DEPSTRUCT; /* ptr to application struct
1111	for I/O functions */
1112
1113	#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1114	png_user_transform_ptr read_user_transform_fn PNG_DEPSTRUCT; /* user read
1115	transform */
1116	#endif
1117
1118	#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1119	png_user_transform_ptr write_user_transform_fn PNG_DEPSTRUCT; /* user write
1120	transform */
1121	#endif
1122
1123	/* These were added in libpng-1.0.2 */
1124	#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1125	#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) \|\| \
1126	defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
1127	png_voidp user_transform_ptr PNG_DEPSTRUCT; /* user supplied struct
1128	for user transform */
1129	png_byte user_transform_depth PNG_DEPSTRUCT; /* bit depth of user
1130	transformed pixels */
1131	png_byte user_transform_channels PNG_DEPSTRUCT; /* channels in user
1132	transformed pixels */
1133	#endif
1134	#endif
1135
1136	png_uint_32 mode PNG_DEPSTRUCT; /* tells us where we are in
1137	the PNG file */
1138	png_uint_32 flags PNG_DEPSTRUCT; /* flags indicating various
1139	things to libpng */
1140	png_uint_32 transformations PNG_DEPSTRUCT; /* which transformations
1141	to perform */
1142
1143	z_stream zstream PNG_DEPSTRUCT; /* pointer to decompression
1144	structure (below) */
1145	png_bytep zbuf PNG_DEPSTRUCT; /* buffer for zlib */
1146	png_size_t zbuf_size PNG_DEPSTRUCT; /* size of zbuf */
1147	int zlib_level PNG_DEPSTRUCT; /* holds zlib compression level */
1148	int zlib_method PNG_DEPSTRUCT; /* holds zlib compression method */
1149	int zlib_window_bits PNG_DEPSTRUCT; /* holds zlib compression window
1150	bits */
1151	int zlib_mem_level PNG_DEPSTRUCT; /* holds zlib compression memory
1152	level */
1153	int zlib_strategy PNG_DEPSTRUCT; /* holds zlib compression
1154	strategy */
1155
1156	png_uint_32 width PNG_DEPSTRUCT; /* width of image in pixels */
1157	png_uint_32 height PNG_DEPSTRUCT; /* height of image in pixels */
1158	png_uint_32 num_rows PNG_DEPSTRUCT; /* number of rows in current pass */
1159	png_uint_32 usr_width PNG_DEPSTRUCT; /* width of row at start of write */
1160	png_size_t rowbytes PNG_DEPSTRUCT; /* size of row in bytes */
1161	#if 0 /* Replaced with the following in libpng-1.4.1 */
1162	png_size_t irowbytes PNG_DEPSTRUCT;
1163	#endif
1164	/* Added in libpng-1.4.1 */
1165	#ifdef PNG_USER_LIMITS_SUPPORTED
1166	/* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
1167	* can occupy when decompressed. 0 means unlimited.
1168	* We will change the typedef from png_size_t to png_alloc_size_t
1169	* in libpng-1.6.0
1170	*/
1171	png_alloc_size_t user_chunk_malloc_max PNG_DEPSTRUCT;
1172	#endif
1173	png_uint_32 iwidth PNG_DEPSTRUCT; /* width of current interlaced
1174	row in pixels */
1175	png_uint_32 row_number PNG_DEPSTRUCT; /* current row in interlace pass */
1176	png_bytep prev_row PNG_DEPSTRUCT; /* buffer to save previous
1177	(unfiltered) row */
1178	png_bytep row_buf PNG_DEPSTRUCT; /* buffer to save current
1179	(unfiltered) row */
1180	png_bytep sub_row PNG_DEPSTRUCT; /* buffer to save "sub" row
1181	when filtering */
1182	png_bytep up_row PNG_DEPSTRUCT; /* buffer to save "up" row
1183	when filtering */
1184	png_bytep avg_row PNG_DEPSTRUCT; /* buffer to save "avg" row
1185	when filtering */
1186	png_bytep paeth_row PNG_DEPSTRUCT; /* buffer to save "Paeth" row
1187	when filtering */
1188	png_row_info row_info PNG_DEPSTRUCT; /* used for transformation
1189	routines */
1190
1191	png_uint_32 idat_size PNG_DEPSTRUCT; /* current IDAT size for read */
1192	png_uint_32 crc PNG_DEPSTRUCT; /* current chunk CRC value */
1193	png_colorp palette PNG_DEPSTRUCT; /* palette from the input file */
1194	png_uint_16 num_palette PNG_DEPSTRUCT; /* number of color entries in
1195	palette */
1196	png_uint_16 num_trans PNG_DEPSTRUCT; /* number of transparency values */
1197	png_byte chunk_name[5] PNG_DEPSTRUCT; /* null-terminated name of current
1198	chunk */
1199	png_byte compression PNG_DEPSTRUCT; /* file compression type
1200	(always 0) */
1201	png_byte filter PNG_DEPSTRUCT; /* file filter type (always 0) */
1202	png_byte interlaced PNG_DEPSTRUCT; /* PNG_INTERLACE_NONE,
1203	PNG_INTERLACE_ADAM7 */
1204	png_byte pass PNG_DEPSTRUCT; /* current interlace pass (0 - 6) */
1205	png_byte do_filter PNG_DEPSTRUCT; /* row filter flags (see
1206	PNG_FILTER_ below ) */
1207	png_byte color_type PNG_DEPSTRUCT; /* color type of file */
1208	png_byte bit_depth PNG_DEPSTRUCT; /* bit depth of file */
1209	png_byte usr_bit_depth PNG_DEPSTRUCT; /* bit depth of users row */
1210	png_byte pixel_depth PNG_DEPSTRUCT; /* number of bits per pixel */
1211	png_byte channels PNG_DEPSTRUCT; /* number of channels in file */
1212	png_byte usr_channels PNG_DEPSTRUCT; /* channels at start of write */
1213	png_byte sig_bytes PNG_DEPSTRUCT; /* magic bytes read/written from
1214	start of file */
1215
1216	#if defined(PNG_READ_FILLER_SUPPORTED) \|\| defined(PNG_WRITE_FILLER_SUPPORTED)
1217	png_uint_16 filler PNG_DEPSTRUCT; /* filler bytes for pixel
1218	expansion */
1219	#endif
1220
1221	#ifdef PNG_bKGD_SUPPORTED
1222	png_byte background_gamma_type PNG_DEPSTRUCT;
1223	# ifdef PNG_FLOATING_POINT_SUPPORTED
1224	float background_gamma PNG_DEPSTRUCT;
1225	# endif
1226	png_color_16 background PNG_DEPSTRUCT; /* background color in
1227	screen gamma space */
1228	#ifdef PNG_READ_GAMMA_SUPPORTED
1229	png_color_16 background_1 PNG_DEPSTRUCT; /* background normalized
1230	to gamma 1.0 */
1231	#endif
1232	#endif /* PNG_bKGD_SUPPORTED */
1233
1234	#ifdef PNG_WRITE_FLUSH_SUPPORTED
1235	png_flush_ptr output_flush_fn PNG_DEPSTRUCT; /* Function for flushing
1236	output */
1237	png_uint_32 flush_dist PNG_DEPSTRUCT; /* how many rows apart to flush,
1238	0 - no flush */
1239	png_uint_32 flush_rows PNG_DEPSTRUCT; /* number of rows written since
1240	last flush */
1241	#endif
1242
1243	#if defined(PNG_READ_GAMMA_SUPPORTED) \|\| defined(PNG_READ_BACKGROUND_SUPPORTED)
1244	int gamma_shift PNG_DEPSTRUCT; /* number of "insignificant" bits
1245	16-bit gamma */
1246	#ifdef PNG_FLOATING_POINT_SUPPORTED
1247	float gamma PNG_DEPSTRUCT; /* file gamma value */
1248	float screen_gamma PNG_DEPSTRUCT; /* screen gamma value
1249	(display_exponent) */
1250	#endif
1251	#endif
1252
1253	#if defined(PNG_READ_GAMMA_SUPPORTED) \|\| defined(PNG_READ_BACKGROUND_SUPPORTED)
1254	png_bytep gamma_table PNG_DEPSTRUCT; /* gamma table for 8-bit
1255	depth files */
1256	png_bytep gamma_from_1 PNG_DEPSTRUCT; /* converts from 1.0 to screen */
1257	png_bytep gamma_to_1 PNG_DEPSTRUCT; /* converts from file to 1.0 */
1258	png_uint_16pp gamma_16_table PNG_DEPSTRUCT; /* gamma table for 16-bit
1259	depth files */
1260	png_uint_16pp gamma_16_from_1 PNG_DEPSTRUCT; /* converts from 1.0 to
1261	screen */
1262	png_uint_16pp gamma_16_to_1 PNG_DEPSTRUCT; /* converts from file to 1.0 */
1263	#endif
1264
1265	#if defined(PNG_READ_GAMMA_SUPPORTED) \|\| defined(PNG_sBIT_SUPPORTED)
1266	png_color_8 sig_bit PNG_DEPSTRUCT; /* significant bits in each
1267	available channel */
1268	#endif
1269
1270	#if defined(PNG_READ_SHIFT_SUPPORTED) \|\| defined(PNG_WRITE_SHIFT_SUPPORTED)
1271	png_color_8 shift PNG_DEPSTRUCT; /* shift for significant bit
1272	tranformation */
1273	#endif
1274
1275	#if defined(PNG_tRNS_SUPPORTED) \|\| defined(PNG_READ_BACKGROUND_SUPPORTED) \
1276	\|\| defined(PNG_READ_EXPAND_SUPPORTED) \|\| defined(PNG_READ_BACKGROUND_SUPPORTED)
1277	png_bytep trans_alpha PNG_DEPSTRUCT; /* alpha values for
1278	paletted files */
1279	png_color_16 trans_color PNG_DEPSTRUCT; /* transparent color for
1280	non-paletted files */
1281	#endif
1282
1283	png_read_status_ptr read_row_fn PNG_DEPSTRUCT; /* called after each
1284	row is decoded */
1285	png_write_status_ptr write_row_fn PNG_DEPSTRUCT; /* called after each
1286	row is encoded */
1287	#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
1288	png_progressive_info_ptr info_fn PNG_DEPSTRUCT; /* called after header
1289	data fully read */
1290	png_progressive_row_ptr row_fn PNG_DEPSTRUCT; /* called after each
1291	prog. row is decoded */
1292	png_progressive_end_ptr end_fn PNG_DEPSTRUCT; /* called after image
1293	is complete */
1294	png_bytep save_buffer_ptr PNG_DEPSTRUCT; /* current location in
1295	save_buffer */
1296	png_bytep save_buffer PNG_DEPSTRUCT; /* buffer for previously
1297	read data */
1298	png_bytep current_buffer_ptr PNG_DEPSTRUCT; /* current location in
1299	current_buffer */
1300	png_bytep current_buffer PNG_DEPSTRUCT; /* buffer for recently
1301	used data */
1302	png_uint_32 push_length PNG_DEPSTRUCT; /* size of current input
1303	chunk */
1304	png_uint_32 skip_length PNG_DEPSTRUCT; /* bytes to skip in
1305	input data */
1306	png_size_t save_buffer_size PNG_DEPSTRUCT; /* amount of data now
1307	in save_buffer */
1308	png_size_t save_buffer_max PNG_DEPSTRUCT; /* total size of
1309	save_buffer */
1310	png_size_t buffer_size PNG_DEPSTRUCT; /* total amount of
1311	available input data */
1312	png_size_t current_buffer_size PNG_DEPSTRUCT; /* amount of data now
1313	in current_buffer */
1314	int process_mode PNG_DEPSTRUCT; /* what push library
1315	is currently doing */
1316	int cur_palette PNG_DEPSTRUCT; /* current push library
1317	palette index */
1318
1319	# ifdef PNG_TEXT_SUPPORTED
1320	png_size_t current_text_size PNG_DEPSTRUCT; /* current size of
1321	text input data */
1322	png_size_t current_text_left PNG_DEPSTRUCT; /* how much text left
1323	to read in input */
1324	png_charp current_text PNG_DEPSTRUCT; /* current text chunk
1325	buffer */
1326	png_charp current_text_ptr PNG_DEPSTRUCT; /* current location
1327	in current_text */
1328	# endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */
1329
1330	#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
1331
1332	#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
1333	/* For the Borland special 64K segment handler */
1334	png_bytepp offset_table_ptr PNG_DEPSTRUCT;
1335	png_bytep offset_table PNG_DEPSTRUCT;
1336	png_uint_16 offset_table_number PNG_DEPSTRUCT;
1337	png_uint_16 offset_table_count PNG_DEPSTRUCT;
1338	png_uint_16 offset_table_count_free PNG_DEPSTRUCT;
1339	#endif
1340
1341	#ifdef PNG_READ_QUANTIZE_SUPPORTED
1342	png_bytep palette_lookup PNG_DEPSTRUCT; /* lookup table for quantizing */
1343	png_bytep quantize_index PNG_DEPSTRUCT; /* index translation for palette
1344	files */
1345	#endif
1346
1347	#if defined(PNG_READ_QUANTIZE_SUPPORTED) \|\| defined(PNG_hIST_SUPPORTED)
1348	png_uint_16p hist PNG_DEPSTRUCT; /* histogram */
1349	#endif
1350
1351	#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
1352	png_byte heuristic_method PNG_DEPSTRUCT; /* heuristic for row
1353	filter selection */
1354	png_byte num_prev_filters PNG_DEPSTRUCT; /* number of weights
1355	for previous rows */
1356	png_bytep prev_filters PNG_DEPSTRUCT; /* filter type(s) of
1357	previous row(s) */
1358	png_uint_16p filter_weights PNG_DEPSTRUCT; /* weight(s) for previous
1359	line(s) */
1360	png_uint_16p inv_filter_weights PNG_DEPSTRUCT; /* 1/weight(s) for
1361	previous line(s) */
1362	png_uint_16p filter_costs PNG_DEPSTRUCT; /* relative filter
1363	calculation cost */
1364	png_uint_16p inv_filter_costs PNG_DEPSTRUCT; /* 1/relative filter
1365	calculation cost */
1366	#endif
1367
1368	#ifdef PNG_TIME_RFC1123_SUPPORTED
1369	png_charp time_buffer PNG_DEPSTRUCT; /* String to hold RFC 1123 time text */
1370	#endif
1371
1372	/* New members added in libpng-1.0.6 */
1373
1374	png_uint_32 free_me PNG_DEPSTRUCT; /* flags items libpng is
1375	responsible for freeing */
1376
1377	#ifdef PNG_USER_CHUNKS_SUPPORTED
1378	png_voidp user_chunk_ptr PNG_DEPSTRUCT;
1379	png_user_chunk_ptr read_user_chunk_fn PNG_DEPSTRUCT; /* user read
1380	chunk handler */
1381	#endif
1382
1383	#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
1384	int num_chunk_list PNG_DEPSTRUCT;
1385	png_bytep chunk_list PNG_DEPSTRUCT;
1386	#endif
1387
1388	/* New members added in libpng-1.0.3 */
1389	#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1390	png_byte rgb_to_gray_status PNG_DEPSTRUCT;
1391	/* These were changed from png_byte in libpng-1.0.6 */
1392	png_uint_16 rgb_to_gray_red_coeff PNG_DEPSTRUCT;
1393	png_uint_16 rgb_to_gray_green_coeff PNG_DEPSTRUCT;
1394	png_uint_16 rgb_to_gray_blue_coeff PNG_DEPSTRUCT;
1395	#endif
1396
1397	/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
1398	#if defined(PNG_MNG_FEATURES_SUPPORTED) \|\| \
1399	defined(PNG_READ_EMPTY_PLTE_SUPPORTED) \|\| \
1400	defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
1401	/* Changed from png_byte to png_uint_32 at version 1.2.0 */
1402	png_uint_32 mng_features_permitted PNG_DEPSTRUCT;
1403	#endif
1404
1405	/* New member added in libpng-1.0.7 */
1406	#if defined(PNG_READ_GAMMA_SUPPORTED) \|\| defined(PNG_READ_BACKGROUND_SUPPORTED)
1407	png_fixed_point int_gamma PNG_DEPSTRUCT;
1408	#endif
1409
1410	/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
1411	#ifdef PNG_MNG_FEATURES_SUPPORTED
1412	png_byte filter_type PNG_DEPSTRUCT;
1413	#endif
1414
1415	/* New members added in libpng-1.2.0 */
1416
1417	/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
1418	#ifdef PNG_USER_MEM_SUPPORTED
1419	png_voidp mem_ptr PNG_DEPSTRUCT; /* user supplied struct for
1420	mem functions */
1421	png_malloc_ptr malloc_fn PNG_DEPSTRUCT; /* function for
1422	allocating memory */
1423	png_free_ptr free_fn PNG_DEPSTRUCT; /* function for
1424	freeing memory */
1425	#endif
1426
1427	/* New member added in libpng-1.0.13 and 1.2.0 */
1428	png_bytep big_row_buf PNG_DEPSTRUCT; /* buffer to save current
1429	(unfiltered) row */
1430
1431	#ifdef PNG_READ_QUANTIZE_SUPPORTED
1432	/* The following three members were added at version 1.0.14 and 1.2.4 */
1433	png_bytep quantize_sort PNG_DEPSTRUCT; /* working sort array */
1434	png_bytep index_to_palette PNG_DEPSTRUCT; /* where the original
1435	index currently is
1436	in the palette */
1437	png_bytep palette_to_index PNG_DEPSTRUCT; /* which original index
1438	points to this
1439	palette color */
1440	#endif
1441
1442	/* New members added in libpng-1.0.16 and 1.2.6 */
1443	png_byte compression_type PNG_DEPSTRUCT;
1444
1445	#ifdef PNG_USER_LIMITS_SUPPORTED
1446	png_uint_32 user_width_max PNG_DEPSTRUCT;
1447	png_uint_32 user_height_max PNG_DEPSTRUCT;
1448	/* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
1449	* chunks that can be stored (0 means unlimited).
1450	*/
1451	png_uint_32 user_chunk_cache_max PNG_DEPSTRUCT;
1452	#endif
1453
1454	/* New member added in libpng-1.0.25 and 1.2.17 */
1455	#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
1456	/* Storage for unknown chunk that the library doesn't recognize. */
1457	png_unknown_chunk unknown_chunk PNG_DEPSTRUCT;
1458	#endif
1459
1460	/* New members added in libpng-1.2.26 */
1461	png_uint_32 old_big_row_buf_size PNG_DEPSTRUCT;
1462	png_uint_32 old_prev_row_size PNG_DEPSTRUCT;
1463
1464	/* New member added in libpng-1.2.30 */
1465	png_charp chunkdata PNG_DEPSTRUCT; /* buffer for reading chunk data */
1466
1467	#ifdef PNG_IO_STATE_SUPPORTED
1468	/* New member added in libpng-1.4.0 */
1469	png_uint_32 io_state PNG_DEPSTRUCT;
1470	#endif
1471	};
1472
1473
1474	/* This triggers a compiler error in png.c, if png.c and png.h
1475	* do not agree upon the version number.
1476	*/
1477	typedef png_structp version_1_4_3;
1478
1479	typedef png_struct FAR * FAR * png_structpp;
1480
1481	/* Here are the function definitions most commonly used. This is not
1482	* the place to find out how to use libpng. See libpng.txt for the
1483	* full explanation, see example.c for the summary. This just provides
1484	* a simple one line description of the use of each function.
1485	*/
1486
1487	/* Returns the version number of the library */
1488	extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));
1489
1490	/* Tell lib we have already handled the first <num_bytes> magic bytes.
1491	* Handling more than 8 bytes from the beginning of the file is an error.
1492	*/
1493	extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,
1494	int num_bytes));
1495
1496	/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
1497	* PNG file. Returns zero if the supplied bytes match the 8-byte PNG
1498	* signature, and non-zero otherwise. Having num_to_check == 0 or
1499	* start > 7 will always fail (ie return non-zero).
1500	*/
1501	extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,
1502	png_size_t num_to_check));
1503
1504	/* Simple signature checking function. This is the same as calling
1505	* png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
1506	*/
1507	#define png_check_sig(sig,n) !png_sig_cmp((sig), 0, (n))
1508
1509	/* Allocate and initialize png_ptr struct for reading, and any other memory. */
1510	extern PNG_EXPORT(png_structp,png_create_read_struct)
1511	PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
1512	png_error_ptr error_fn, png_error_ptr warn_fn)) PNG_ALLOCATED;
1513
1514	/* Allocate and initialize png_ptr struct for writing, and any other memory */
1515	extern PNG_EXPORT(png_structp,png_create_write_struct)
1516	PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
1517	png_error_ptr error_fn, png_error_ptr warn_fn)) PNG_ALLOCATED;
1518
1519	extern PNG_EXPORT(png_size_t,png_get_compression_buffer_size)
1520	PNGARG((png_structp png_ptr));
1521
1522	extern PNG_EXPORT(void,png_set_compression_buffer_size)
1523	PNGARG((png_structp png_ptr, png_size_t size));
1524
1525	/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
1526	* match up.
1527	*/
1528	#ifdef PNG_SETJMP_SUPPORTED
1529	/* This function returns the jmp_buf built in to *png_ptr. It must be
1530	* supplied with an appropriate 'longjmp' function to use on that jmp_buf
1531	* unless the default error function is overridden in which case NULL is
1532	* acceptable. The size of the jmp_buf is checked against the actual size
1533	* allocated by the library - the call will return NULL on a mismatch
1534	* indicating an ABI mismatch.
1535	*/
1536	extern PNG_EXPORT(jmp_buf*, png_set_longjmp_fn)
1537	PNGARG((png_structp png_ptr, png_longjmp_ptr longjmp_fn, size_t
1538	jmp_buf_size));
1539	# define png_jmpbuf(png_ptr) \
1540	(*png_set_longjmp_fn((png_ptr), longjmp, sizeof (jmp_buf)))
1541	#else
1542	# define png_jmpbuf(png_ptr) \
1543	(LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
1544	#endif
1545
1546	#ifdef PNG_READ_SUPPORTED
1547	/* Reset the compression stream */
1548	extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));
1549	#endif
1550
1551	/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
1552	#ifdef PNG_USER_MEM_SUPPORTED
1553	extern PNG_EXPORT(png_structp,png_create_read_struct_2)
1554	PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
1555	png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
1556	png_malloc_ptr malloc_fn, png_free_ptr free_fn)) PNG_ALLOCATED;
1557	extern PNG_EXPORT(png_structp,png_create_write_struct_2)
1558	PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
1559	png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
1560	png_malloc_ptr malloc_fn, png_free_ptr free_fn)) PNG_ALLOCATED;
1561	#endif
1562
1563	/* Write the PNG file signature. */
1564	extern PNG_EXPORT(void,png_write_sig) PNGARG((png_structp png_ptr));
1565
1566	/* Write a PNG chunk - size, type, (optional) data, CRC. */
1567	extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,
1568	png_bytep chunk_name, png_bytep data, png_size_t length));
1569
1570	/* Write the start of a PNG chunk - length and chunk name. */
1571	extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,
1572	png_bytep chunk_name, png_uint_32 length));
1573
1574	/* Write the data of a PNG chunk started with png_write_chunk_start(). */
1575	extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,
1576	png_bytep data, png_size_t length));
1577
1578	/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
1579	extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));
1580
1581	/* Allocate and initialize the info structure */
1582	extern PNG_EXPORT(png_infop,png_create_info_struct)
1583	PNGARG((png_structp png_ptr)) PNG_ALLOCATED;
1584
1585	extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,
1586	png_size_t png_info_struct_size));
1587
1588	/* Writes all the PNG information before the image. */
1589	extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
1590	png_infop info_ptr));
1591	extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
1592	png_infop info_ptr));
1593
1594	#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1595	/* Read the information before the actual image data. */
1596	extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
1597	png_infop info_ptr));
1598	#endif
1599
1600	#ifdef PNG_TIME_RFC1123_SUPPORTED
1601	extern PNG_EXPORT(png_charp,png_convert_to_rfc1123)
1602	PNGARG((png_structp png_ptr, png_timep ptime));
1603	#endif
1604
1605	#ifdef PNG_CONVERT_tIME_SUPPORTED
1606	/* Convert from a struct tm to png_time */
1607	extern PNG_EXPORT(void,png_convert_from_struct_tm) PNGARG((png_timep ptime,
1608	struct tm FAR * ttime));
1609
1610	/* Convert from time_t to png_time. Uses gmtime() */
1611	extern PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,
1612	time_t ttime));
1613	#endif /* PNG_CONVERT_tIME_SUPPORTED */
1614
1615	#ifdef PNG_READ_EXPAND_SUPPORTED
1616	/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
1617	extern PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));
1618	extern PNG_EXPORT(void,png_set_expand_gray_1_2_4_to_8) PNGARG((png_structp
1619	png_ptr));
1620	extern PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));
1621	extern PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));
1622	#endif
1623
1624	#if defined(PNG_READ_BGR_SUPPORTED) \|\| defined(PNG_WRITE_BGR_SUPPORTED)
1625	/* Use blue, green, red order for pixels. */
1626	extern PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));
1627	#endif
1628
1629	#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1630	/* Expand the grayscale to 24-bit RGB if necessary. */
1631	extern PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));
1632	#endif
1633
1634	#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1635	/* Reduce RGB to grayscale. */
1636	#ifdef PNG_FLOATING_POINT_SUPPORTED
1637	extern PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,
1638	int error_action, double red, double green ));
1639	#endif
1640	extern PNG_EXPORT(void,png_set_rgb_to_gray_fixed) PNGARG((png_structp png_ptr,
1641	int error_action, png_fixed_point red, png_fixed_point green ));
1642	extern PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_structp
1643	png_ptr));
1644	#endif
1645
1646	extern PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,
1647	png_colorp palette));
1648
1649	#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1650	extern PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));
1651	#endif
1652
1653	#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) \|\| \
1654	defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1655	extern PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));
1656	#endif
1657
1658	#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) \|\| \
1659	defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1660	extern PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));
1661	#endif
1662
1663	#if defined(PNG_READ_FILLER_SUPPORTED) \|\| defined(PNG_WRITE_FILLER_SUPPORTED)
1664	/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
1665	extern PNG_EXPORT(void,png_set_filler) PNGARG((png_structp png_ptr,
1666	png_uint_32 filler, int flags));
1667	/* The values of the PNG_FILLER_ defines should NOT be changed */
1668	#define PNG_FILLER_BEFORE 0
1669	#define PNG_FILLER_AFTER 1
1670	/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
1671	extern PNG_EXPORT(void,png_set_add_alpha) PNGARG((png_structp png_ptr,
1672	png_uint_32 filler, int flags));
1673	#endif /* PNG_READ_FILLER_SUPPORTED \|\| PNG_WRITE_FILLER_SUPPORTED */
1674
1675	#if defined(PNG_READ_SWAP_SUPPORTED) \|\| defined(PNG_WRITE_SWAP_SUPPORTED)
1676	/* Swap bytes in 16-bit depth files. */
1677	extern PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));
1678	#endif
1679
1680	#if defined(PNG_READ_PACK_SUPPORTED) \|\| defined(PNG_WRITE_PACK_SUPPORTED)
1681	/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
1682	extern PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));
1683	#endif
1684
1685	#if defined(PNG_READ_PACKSWAP_SUPPORTED) \|\| \
1686	defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1687	/* Swap packing order of pixels in bytes. */
1688	extern PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));
1689	#endif
1690
1691	#if defined(PNG_READ_SHIFT_SUPPORTED) \|\| defined(PNG_WRITE_SHIFT_SUPPORTED)
1692	/* Converts files to legal bit depths. */
1693	extern PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,
1694	png_color_8p true_bits));
1695	#endif
1696
1697	#if defined(PNG_READ_INTERLACING_SUPPORTED) \|\| \
1698	defined(PNG_WRITE_INTERLACING_SUPPORTED)
1699	/* Have the code handle the interlacing. Returns the number of passes. */
1700	extern PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));
1701	#endif
1702
1703	#if defined(PNG_READ_INVERT_SUPPORTED) \|\| defined(PNG_WRITE_INVERT_SUPPORTED)
1704	/* Invert monochrome files */
1705	extern PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));
1706	#endif
1707
1708	#ifdef PNG_READ_BACKGROUND_SUPPORTED
1709	/* Handle alpha and tRNS by replacing with a background color. */
1710	#ifdef PNG_FLOATING_POINT_SUPPORTED
1711	extern PNG_EXPORT(void,png_set_background) PNGARG((png_structp png_ptr,
1712	png_color_16p background_color, int background_gamma_code,
1713	int need_expand, double background_gamma));
1714	#endif
1715	#define PNG_BACKGROUND_GAMMA_UNKNOWN 0
1716	#define PNG_BACKGROUND_GAMMA_SCREEN 1
1717	#define PNG_BACKGROUND_GAMMA_FILE 2
1718	#define PNG_BACKGROUND_GAMMA_UNIQUE 3
1719	#endif
1720
1721	#ifdef PNG_READ_16_TO_8_SUPPORTED
1722	/* Strip the second byte of information from a 16-bit depth file. */
1723	extern PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));
1724	#endif
1725
1726	#ifdef PNG_READ_QUANTIZE_SUPPORTED
1727	/* Turn on quantizing, and reduce the palette to the number of colors
1728	* available. Prior to libpng-1.4.2, this was png_set_dither().
1729	*/
1730	extern PNG_EXPORT(void,png_set_quantize) PNGARG((png_structp png_ptr,
1731	png_colorp palette, int num_palette, int maximum_colors,
1732	png_uint_16p histogram, int full_quantize));
1733	#endif
1734	/* This migration aid will be removed from libpng-1.5.0 */
1735	#define png_set_dither png_set_quantize
1736
1737	#ifdef PNG_READ_GAMMA_SUPPORTED
1738	/* Handle gamma correction. Screen_gamma=(display_exponent) */
1739	#ifdef PNG_FLOATING_POINT_SUPPORTED
1740	extern PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,
1741	double screen_gamma, double default_file_gamma));
1742	#endif
1743	#endif
1744
1745
1746	#ifdef PNG_WRITE_FLUSH_SUPPORTED
1747	/* Set how many lines between output flushes - 0 for no flushing */
1748	extern PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));
1749	/* Flush the current PNG output buffer */
1750	extern PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));
1751	#endif
1752
1753	/* Optional update palette with requested transformations */
1754	extern PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));
1755
1756	/* Optional call to update the users info structure */
1757	extern PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,
1758	png_infop info_ptr));
1759
1760	#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1761	/* Read one or more rows of image data. */
1762	extern PNG_EXPORT(void,png_read_rows) PNGARG((png_structp png_ptr,
1763	png_bytepp row, png_bytepp display_row, png_uint_32 num_rows));
1764	#endif
1765
1766	#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1767	/* Read a row of data. */
1768	extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,
1769	png_bytep row,
1770	png_bytep display_row));
1771	#endif
1772
1773	#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1774	/* Read the whole image into memory at once. */
1775	extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
1776	png_bytepp image));
1777	#endif
1778
1779	/* Write a row of image data */
1780	extern PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,
1781	png_bytep row));
1782
1783	/* Write a few rows of image data */
1784	extern PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,
1785	png_bytepp row, png_uint_32 num_rows));
1786
1787	/* Write the image data */
1788	extern PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,
1789	png_bytepp image));
1790
1791	/* Write the end of the PNG file. */
1792	extern PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,
1793	png_infop info_ptr));
1794
1795	#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
1796	/* Read the end of the PNG file. */
1797	extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
1798	png_infop info_ptr));
1799	#endif
1800
1801	/* Free any memory associated with the png_info_struct */
1802	extern PNG_EXPORT(void,png_destroy_info_struct) PNGARG((png_structp png_ptr,
1803	png_infopp info_ptr_ptr));
1804
1805	/* Free any memory associated with the png_struct and the png_info_structs */
1806	extern PNG_EXPORT(void,png_destroy_read_struct) PNGARG((png_structpp
1807	png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
1808
1809	/* Free any memory associated with the png_struct and the png_info_structs */
1810	extern PNG_EXPORT(void,png_destroy_write_struct)
1811	PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));
1812
1813	/* Set the libpng method of handling chunk CRC errors */
1814	extern PNG_EXPORT(void,png_set_crc_action) PNGARG((png_structp png_ptr,
1815	int crit_action, int ancil_action));
1816
1817	/* Values for png_set_crc_action() to say how to handle CRC errors in
1818	* ancillary and critical chunks, and whether to use the data contained
1819	* therein. Note that it is impossible to "discard" data in a critical
1820	* chunk. For versions prior to 0.90, the action was always error/quit,
1821	* whereas in version 0.90 and later, the action for CRC errors in ancillary
1822	* chunks is warn/discard. These values should NOT be changed.
1823	*
1824	* value action:critical action:ancillary
1825	*/
1826	#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
1827	#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
1828	#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
1829	#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
1830	#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
1831	#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
1832
1833	/* These functions give the user control over the scan-line filtering in
1834	* libpng and the compression methods used by zlib. These functions are
1835	* mainly useful for testing, as the defaults should work with most users.
1836	* Those users who are tight on memory or want faster performance at the
1837	* expense of compression can modify them. See the compression library
1838	* header file (zlib.h) for an explination of the compression functions.
1839	*/
1840
1841	/* Set the filtering method(s) used by libpng. Currently, the only valid
1842	* value for "method" is 0.
1843	*/
1844	extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,
1845	int filters));
1846
1847	/* Flags for png_set_filter() to say which filters to use. The flags
1848	* are chosen so that they don't conflict with real filter types
1849	* below, in case they are supplied instead of the #defined constants.
1850	* These values should NOT be changed.
1851	*/
1852	#define PNG_NO_FILTERS 0x00
1853	#define PNG_FILTER_NONE 0x08
1854	#define PNG_FILTER_SUB 0x10
1855	#define PNG_FILTER_UP 0x20
1856	#define PNG_FILTER_AVG 0x40
1857	#define PNG_FILTER_PAETH 0x80
1858	#define PNG_ALL_FILTERS (PNG_FILTER_NONE \| PNG_FILTER_SUB \| PNG_FILTER_UP \| \
1859	PNG_FILTER_AVG \| PNG_FILTER_PAETH)
1860
1861	/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
1862	* These defines should NOT be changed.
1863	*/
1864	#define PNG_FILTER_VALUE_NONE 0
1865	#define PNG_FILTER_VALUE_SUB 1
1866	#define PNG_FILTER_VALUE_UP 2
1867	#define PNG_FILTER_VALUE_AVG 3
1868	#define PNG_FILTER_VALUE_PAETH 4
1869	#define PNG_FILTER_VALUE_LAST 5
1870
1871	#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
1872	/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
1873	* defines, either the default (minimum-sum-of-absolute-differences), or
1874	* the experimental method (weighted-minimum-sum-of-absolute-differences).
1875	*
1876	* Weights are factors >= 1.0, indicating how important it is to keep the
1877	* filter type consistent between rows. Larger numbers mean the current
1878	* filter is that many times as likely to be the same as the "num_weights"
1879	* previous filters. This is cumulative for each previous row with a weight.
1880	* There needs to be "num_weights" values in "filter_weights", or it can be
1881	* NULL if the weights aren't being specified. Weights have no influence on
1882	* the selection of the first row filter. Well chosen weights can (in theory)
1883	* improve the compression for a given image.
1884	*
1885	* Costs are factors >= 1.0 indicating the relative decoding costs of a
1886	* filter type. Higher costs indicate more decoding expense, and are
1887	* therefore less likely to be selected over a filter with lower computational
1888	* costs. There needs to be a value in "filter_costs" for each valid filter
1889	* type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
1890	* setting the costs. Costs try to improve the speed of decompression without
1891	* unduly increasing the compressed image size.
1892	*
1893	* A negative weight or cost indicates the default value is to be used, and
1894	* values in the range [0.0, 1.0) indicate the value is to remain unchanged.
1895	* The default values for both weights and costs are currently 1.0, but may
1896	* change if good general weighting/cost heuristics can be found. If both
1897	* the weights and costs are set to 1.0, this degenerates the WEIGHTED method
1898	* to the UNWEIGHTED method, but with added encoding time/computation.
1899	*/
1900	#ifdef PNG_FLOATING_POINT_SUPPORTED
1901	extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
1902	int heuristic_method, int num_weights, png_doublep filter_weights,
1903	png_doublep filter_costs));
1904	#endif
1905	#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1906
1907	/* Heuristic used for row filter selection. These defines should NOT be
1908	* changed.
1909	*/
1910	#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
1911	#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
1912	#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
1913	#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
1914
1915	/* Set the library compression level. Currently, valid values range from
1916	* 0 - 9, corresponding directly to the zlib compression levels 0 - 9
1917	* (0 - no compression, 9 - "maximal" compression). Note that tests have
1918	* shown that zlib compression levels 3-6 usually perform as well as level 9
1919	* for PNG images, and do considerably fewer caclulations. In the future,
1920	* these values may not correspond directly to the zlib compression levels.
1921	*/
1922	extern PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,
1923	int level));
1924
1925	extern PNG_EXPORT(void,png_set_compression_mem_level)
1926	PNGARG((png_structp png_ptr, int mem_level));
1927
1928	extern PNG_EXPORT(void,png_set_compression_strategy)
1929	PNGARG((png_structp png_ptr, int strategy));
1930
1931	extern PNG_EXPORT(void,png_set_compression_window_bits)
1932	PNGARG((png_structp png_ptr, int window_bits));
1933
1934	extern PNG_EXPORT(void,png_set_compression_method) PNGARG((png_structp png_ptr,
1935	int method));
1936
1937	/* These next functions are called for input/output, memory, and error
1938	* handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
1939	* and call standard C I/O routines such as fread(), fwrite(), and
1940	* fprintf(). These functions can be made to use other I/O routines
1941	* at run time for those applications that need to handle I/O in a
1942	* different manner by calling png_set_???_fn(). See libpng.txt for
1943	* more information.
1944	*/
1945
1946	#ifdef PNG_STDIO_SUPPORTED
1947	/* Initialize the input/output for the PNG file to the default functions. */
1948	extern PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr,
1949	png_FILE_p fp));
1950	#endif
1951
1952	/* Replace the (error and abort), and warning functions with user
1953	* supplied functions. If no messages are to be printed you must still
1954	* write and use replacement functions. The replacement error_fn should
1955	* still do a longjmp to the last setjmp location if you are using this
1956	* method of error handling. If error_fn or warning_fn is NULL, the
1957	* default function will be used.
1958	*/
1959
1960	extern PNG_EXPORT(void,png_set_error_fn) PNGARG((png_structp png_ptr,
1961	png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
1962
1963	/* Return the user pointer associated with the error functions */
1964	extern PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_structp png_ptr));
1965
1966	/* Replace the default data output functions with a user supplied one(s).
1967	* If buffered output is not used, then output_flush_fn can be set to NULL.
1968	* If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
1969	* output_flush_fn will be ignored (and thus can be NULL).
1970	* It is probably a mistake to use NULL for output_flush_fn if
1971	* write_data_fn is not also NULL unless you have built libpng with
1972	* PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
1973	* default flush function, which uses the standard *FILE structure, will
1974	* be used.
1975	*/
1976	extern PNG_EXPORT(void,png_set_write_fn) PNGARG((png_structp png_ptr,
1977	png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
1978
1979	/* Replace the default data input function with a user supplied one. */
1980	extern PNG_EXPORT(void,png_set_read_fn) PNGARG((png_structp png_ptr,
1981	png_voidp io_ptr, png_rw_ptr read_data_fn));
1982
1983	/* Return the user pointer associated with the I/O functions */
1984	extern PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));
1985
1986	extern PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,
1987	png_read_status_ptr read_row_fn));
1988
1989	extern PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,
1990	png_write_status_ptr write_row_fn));
1991
1992	#ifdef PNG_USER_MEM_SUPPORTED
1993	/* Replace the default memory allocation functions with user supplied one(s). */
1994	extern PNG_EXPORT(void,png_set_mem_fn) PNGARG((png_structp png_ptr,
1995	png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn));
1996	/* Return the user pointer associated with the memory functions */
1997	extern PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_structp png_ptr));
1998	#endif
1999
2000	#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
2001	extern PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp
2002	png_ptr, png_user_transform_ptr read_user_transform_fn));
2003	#endif
2004
2005	#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
2006	extern PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp
2007	png_ptr, png_user_transform_ptr write_user_transform_fn));
2008	#endif
2009
2010	#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) \|\| \
2011	defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
2012	extern PNG_EXPORT(void,png_set_user_transform_info) PNGARG((png_structp
2013	png_ptr, png_voidp user_transform_ptr, int user_transform_depth,
2014	int user_transform_channels));
2015	/* Return the user pointer associated with the user transform functions */
2016	extern PNG_EXPORT(png_voidp,png_get_user_transform_ptr)
2017	PNGARG((png_structp png_ptr));
2018	#endif
2019
2020	#ifdef PNG_USER_CHUNKS_SUPPORTED
2021	extern PNG_EXPORT(void,png_set_read_user_chunk_fn) PNGARG((png_structp png_ptr,
2022	png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
2023	extern PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_structp
2024	png_ptr));
2025	#endif
2026
2027	#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
2028	/* Sets the function callbacks for the push reader, and a pointer to a
2029	* user-defined structure available to the callback functions.
2030	*/
2031	extern PNG_EXPORT(void,png_set_progressive_read_fn) PNGARG((png_structp png_ptr,
2032	png_voidp progressive_ptr,
2033	png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
2034	png_progressive_end_ptr end_fn));
2035
2036	/* Returns the user pointer associated with the push read functions */
2037	extern PNG_EXPORT(png_voidp,png_get_progressive_ptr)
2038	PNGARG((png_structp png_ptr));
2039
2040	/* Function to be called when data becomes available */
2041	extern PNG_EXPORT(void,png_process_data) PNGARG((png_structp png_ptr,
2042	png_infop info_ptr, png_bytep buffer, png_size_t buffer_size));
2043
2044	/* Function that combines rows. Not very much different than the
2045	* png_combine_row() call. Is this even used?????
2046	*/
2047	extern PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,
2048	png_bytep old_row, png_bytep new_row));
2049	#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
2050
2051	extern PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,
2052	png_alloc_size_t size)) PNG_ALLOCATED;
2053	/* Added at libpng version 1.4.0 */
2054	extern PNG_EXPORT(png_voidp,png_calloc) PNGARG((png_structp png_ptr,
2055	png_alloc_size_t size)) PNG_ALLOCATED;
2056
2057	/* Added at libpng version 1.2.4 */
2058	extern PNG_EXPORT(png_voidp,png_malloc_warn) PNGARG((png_structp png_ptr,
2059	png_alloc_size_t size)) PNG_ALLOCATED;
2060
2061	/* Frees a pointer allocated by png_malloc() */
2062	extern PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));
2063
2064	/* Free data that was allocated internally */
2065	extern PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,
2066	png_infop info_ptr, png_uint_32 free_me, int num));
2067	/* Reassign responsibility for freeing existing data, whether allocated
2068	* by libpng or by the application */
2069	extern PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,
2070	png_infop info_ptr, int freer, png_uint_32 mask));
2071	/* Assignments for png_data_freer */
2072	#define PNG_DESTROY_WILL_FREE_DATA 1
2073	#define PNG_SET_WILL_FREE_DATA 1
2074	#define PNG_USER_WILL_FREE_DATA 2
2075	/* Flags for png_ptr->free_me and info_ptr->free_me */
2076	#define PNG_FREE_HIST 0x0008
2077	#define PNG_FREE_ICCP 0x0010
2078	#define PNG_FREE_SPLT 0x0020
2079	#define PNG_FREE_ROWS 0x0040
2080	#define PNG_FREE_PCAL 0x0080
2081	#define PNG_FREE_SCAL 0x0100
2082	#define PNG_FREE_UNKN 0x0200
2083	#define PNG_FREE_LIST 0x0400
2084	#define PNG_FREE_PLTE 0x1000
2085	#define PNG_FREE_TRNS 0x2000
2086	#define PNG_FREE_TEXT 0x4000
2087	#define PNG_FREE_ALL 0x7fff
2088	#define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT\|PNG_FREE_TEXT\|PNG_FREE_UNKN */
2089
2090	#ifdef PNG_USER_MEM_SUPPORTED
2091	extern PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,
2092	png_alloc_size_t size)) PNG_ALLOCATED;
2093	extern PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,
2094	png_voidp ptr));
2095	#endif
2096
2097	#ifndef PNG_NO_ERROR_TEXT
2098	/* Fatal error in PNG image of libpng - can't continue */
2099	extern PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,
2100	png_const_charp error_message)) PNG_NORETURN;
2101
2102	/* The same, but the chunk name is prepended to the error string. */
2103	extern PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,
2104	png_const_charp error_message)) PNG_NORETURN;
2105
2106	#else
2107	/* Fatal error in PNG image of libpng - can't continue */
2108	extern PNG_EXPORT(void,png_err) PNGARG((png_structp png_ptr)) PNG_NORETURN;
2109	#endif
2110
2111	/* Non-fatal error in libpng. Can continue, but may have a problem. */
2112	extern PNG_EXPORT(void,png_warning) PNGARG((png_structp png_ptr,
2113	png_const_charp warning_message));
2114
2115	/* Non-fatal error in libpng, chunk name is prepended to message. */
2116	extern PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,
2117	png_const_charp warning_message));
2118
2119	#ifdef PNG_BENIGN_ERRORS_SUPPORTED
2120	/* Benign error in libpng. Can continue, but may have a problem.
2121	* User can choose whether to handle as a fatal error or as a warning. */
2122	extern PNG_EXPORT(void,png_benign_error) PNGARG((png_structp png_ptr,
2123	png_const_charp warning_message));
2124
2125	/* Same, chunk name is prepended to message. */
2126	extern PNG_EXPORT(void,png_chunk_benign_error) PNGARG((png_structp png_ptr,
2127	png_const_charp warning_message));
2128
2129	extern PNG_EXPORT(void,png_set_benign_errors) PNGARG((png_structp
2130	png_ptr, int allowed));
2131	#endif
2132
2133	/* The png_set_<chunk> functions are for storing values in the png_info_struct.
2134	* Similarly, the png_get_<chunk> calls are used to read values from the
2135	* png_info_struct, either storing the parameters in the passed variables, or
2136	* setting pointers into the png_info_struct where the data is stored. The
2137	* png_get_<chunk> functions return a non-zero value if the data was available
2138	* in info_ptr, or return zero and do not change any of the parameters if the
2139	* data was not available.
2140	*
2141	* These functions should be used instead of directly accessing png_info
2142	* to avoid problems with future changes in the size and internal layout of
2143	* png_info_struct.
2144	*/
2145	/* Returns "flag" if chunk data is valid in info_ptr. */
2146	extern PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_structp png_ptr,
2147	png_infop info_ptr, png_uint_32 flag));
2148
2149	/* Returns number of bytes needed to hold a transformed row. */
2150	extern PNG_EXPORT(png_size_t,png_get_rowbytes) PNGARG((png_structp png_ptr,
2151	png_infop info_ptr));
2152
2153	#ifdef PNG_INFO_IMAGE_SUPPORTED
2154	/* Returns row_pointers, which is an array of pointers to scanlines that was
2155	* returned from png_read_png().
2156	*/
2157	extern PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_structp png_ptr,
2158	png_infop info_ptr));
2159	/* Set row_pointers, which is an array of pointers to scanlines for use
2160	* by png_write_png().
2161	*/
2162	extern PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,
2163	png_infop info_ptr, png_bytepp row_pointers));
2164	#endif
2165
2166	/* Returns number of color channels in image. */
2167	extern PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_structp png_ptr,
2168	png_infop info_ptr));
2169
2170	#ifdef PNG_EASY_ACCESS_SUPPORTED
2171	/* Returns image width in pixels. */
2172	extern PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_structp
2173	png_ptr, png_infop info_ptr));
2174
2175	/* Returns image height in pixels. */
2176	extern PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_structp
2177	png_ptr, png_infop info_ptr));
2178
2179	/* Returns image bit_depth. */
2180	extern PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_structp
2181	png_ptr, png_infop info_ptr));
2182
2183	/* Returns image color_type. */
2184	extern PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_structp
2185	png_ptr, png_infop info_ptr));
2186
2187	/* Returns image filter_type. */
2188	extern PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_structp
2189	png_ptr, png_infop info_ptr));
2190
2191	/* Returns image interlace_type. */
2192	extern PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_structp
2193	png_ptr, png_infop info_ptr));
2194
2195	/* Returns image compression_type. */
2196	extern PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_structp
2197	png_ptr, png_infop info_ptr));
2198
2199	/* Returns image resolution in pixels per meter, from pHYs chunk data. */
2200	extern PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_structp
2201	png_ptr, png_infop info_ptr));
2202	extern PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_structp
2203	png_ptr, png_infop info_ptr));
2204	extern PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_structp
2205	png_ptr, png_infop info_ptr));
2206
2207	/* Returns pixel aspect ratio, computed from pHYs chunk data. */
2208	#ifdef PNG_FLOATING_POINT_SUPPORTED
2209	extern PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_structp
2210	png_ptr, png_infop info_ptr));
2211	#endif
2212
2213	/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
2214	extern PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_structp
2215	png_ptr, png_infop info_ptr));
2216	extern PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_structp
2217	png_ptr, png_infop info_ptr));
2218	extern PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_structp
2219	png_ptr, png_infop info_ptr));
2220	extern PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_structp
2221	png_ptr, png_infop info_ptr));
2222
2223	#endif /* PNG_EASY_ACCESS_SUPPORTED */
2224
2225	/* Returns pointer to signature string read from PNG header */
2226	extern PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_structp png_ptr,
2227	png_infop info_ptr));
2228
2229	#ifdef PNG_bKGD_SUPPORTED
2230	extern PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_structp png_ptr,
2231	png_infop info_ptr, png_color_16p *background));
2232	#endif
2233
2234	#ifdef PNG_bKGD_SUPPORTED
2235	extern PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,
2236	png_infop info_ptr, png_color_16p background));
2237	#endif
2238
2239	#ifdef PNG_cHRM_SUPPORTED
2240	#ifdef PNG_FLOATING_POINT_SUPPORTED
2241	extern PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_structp png_ptr,
2242	png_infop info_ptr, double white_x, double white_y, double *red_x,
2243	double red_y, double green_x, double green_y, double blue_x,
2244	double *blue_y));
2245	#endif
2246	#ifdef PNG_FIXED_POINT_SUPPORTED
2247	extern PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_structp png_ptr,
2248	png_infop info_ptr, png_fixed_point *int_white_x, png_fixed_point
2249	int_white_y, png_fixed_point int_red_x, png_fixed_point *int_red_y,
2250	png_fixed_point int_green_x, png_fixed_point int_green_y, png_fixed_point
2251	int_blue_x, png_fixed_point int_blue_y));
2252	#endif
2253	#endif
2254
2255	#ifdef PNG_cHRM_SUPPORTED
2256	#ifdef PNG_FLOATING_POINT_SUPPORTED
2257	extern PNG_EXPORT(void,png_set_cHRM) PNGARG((png_structp png_ptr,
2258	png_infop info_ptr, double white_x, double white_y, double red_x,
2259	double red_y, double green_x, double green_y, double blue_x, double blue_y));
2260	#endif
2261	#ifdef PNG_FIXED_POINT_SUPPORTED
2262	extern PNG_EXPORT(void,png_set_cHRM_fixed) PNGARG((png_structp png_ptr,
2263	png_infop info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y,
2264	png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
2265	int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
2266	png_fixed_point int_blue_y));
2267	#endif
2268	#endif
2269
2270	#ifdef PNG_gAMA_SUPPORTED
2271	#ifdef PNG_FLOATING_POINT_SUPPORTED
2272	extern PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_structp png_ptr,
2273	png_infop info_ptr, double *file_gamma));
2274	#endif
2275	extern PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_structp png_ptr,
2276	png_infop info_ptr, png_fixed_point *int_file_gamma));
2277	#endif
2278
2279	#ifdef PNG_gAMA_SUPPORTED
2280	#ifdef PNG_FLOATING_POINT_SUPPORTED
2281	extern PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,
2282	png_infop info_ptr, double file_gamma));
2283	#endif
2284	extern PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,
2285	png_infop info_ptr, png_fixed_point int_file_gamma));
2286	#endif
2287
2288	#ifdef PNG_hIST_SUPPORTED
2289	extern PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_structp png_ptr,
2290	png_infop info_ptr, png_uint_16p *hist));
2291	#endif
2292
2293	#ifdef PNG_hIST_SUPPORTED
2294	extern PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,
2295	png_infop info_ptr, png_uint_16p hist));
2296	#endif
2297
2298	extern PNG_EXPORT(png_uint_32,png_get_IHDR) PNGARG((png_structp png_ptr,
2299	png_infop info_ptr, png_uint_32 width, png_uint_32 height,
2300	int bit_depth, int color_type, int *interlace_method,
2301	int compression_method, int filter_method));
2302
2303	extern PNG_EXPORT(void,png_set_IHDR) PNGARG((png_structp png_ptr,
2304	png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
2305	int color_type, int interlace_method, int compression_method,
2306	int filter_method));
2307
2308	#ifdef PNG_oFFs_SUPPORTED
2309	extern PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_structp png_ptr,
2310	png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2311	int *unit_type));
2312	#endif
2313
2314	#ifdef PNG_oFFs_SUPPORTED
2315	extern PNG_EXPORT(void,png_set_oFFs) PNGARG((png_structp png_ptr,
2316	png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,
2317	int unit_type));
2318	#endif
2319
2320	#ifdef PNG_pCAL_SUPPORTED
2321	extern PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_structp png_ptr,
2322	png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 *X1,
2323	int type, int nparams, png_charp units, png_charpp params));
2324	#endif
2325
2326	#ifdef PNG_pCAL_SUPPORTED
2327	extern PNG_EXPORT(void,png_set_pCAL) PNGARG((png_structp png_ptr,
2328	png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1,
2329	int type, int nparams, png_charp units, png_charpp params));
2330	#endif
2331
2332	#ifdef PNG_pHYs_SUPPORTED
2333	extern PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_structp png_ptr,
2334	png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int *unit_type));
2335	#endif
2336
2337	#ifdef PNG_pHYs_SUPPORTED
2338	extern PNG_EXPORT(void,png_set_pHYs) PNGARG((png_structp png_ptr,
2339	png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
2340	#endif
2341
2342	extern PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_structp png_ptr,
2343	png_infop info_ptr, png_colorp palette, int num_palette));
2344
2345	extern PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,
2346	png_infop info_ptr, png_colorp palette, int num_palette));
2347
2348	#ifdef PNG_sBIT_SUPPORTED
2349	extern PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_structp png_ptr,
2350	png_infop info_ptr, png_color_8p *sig_bit));
2351	#endif
2352
2353	#ifdef PNG_sBIT_SUPPORTED
2354	extern PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,
2355	png_infop info_ptr, png_color_8p sig_bit));
2356	#endif
2357
2358	#ifdef PNG_sRGB_SUPPORTED
2359	extern PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_structp png_ptr,
2360	png_infop info_ptr, int *intent));
2361	#endif
2362
2363	#ifdef PNG_sRGB_SUPPORTED
2364	extern PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,
2365	png_infop info_ptr, int intent));
2366	extern PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,
2367	png_infop info_ptr, int intent));
2368	#endif
2369
2370	#ifdef PNG_iCCP_SUPPORTED
2371	extern PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_structp png_ptr,
2372	png_infop info_ptr, png_charpp name, int *compression_type,
2373	png_charpp profile, png_uint_32 *proflen));
2374	/* Note to maintainer: profile should be png_bytepp */
2375	#endif
2376
2377	#ifdef PNG_iCCP_SUPPORTED
2378	extern PNG_EXPORT(void,png_set_iCCP) PNGARG((png_structp png_ptr,
2379	png_infop info_ptr, png_charp name, int compression_type,
2380	png_charp profile, png_uint_32 proflen));
2381	/* Note to maintainer: profile should be png_bytep */
2382	#endif
2383
2384	#ifdef PNG_sPLT_SUPPORTED
2385	extern PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_structp png_ptr,
2386	png_infop info_ptr, png_sPLT_tpp entries));
2387	#endif
2388
2389	#ifdef PNG_sPLT_SUPPORTED
2390	extern PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,
2391	png_infop info_ptr, png_sPLT_tp entries, int nentries));
2392	#endif
2393
2394	#ifdef PNG_TEXT_SUPPORTED
2395	/* png_get_text also returns the number of text chunks in num_text /
2396	extern PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_structp png_ptr,
2397	png_infop info_ptr, png_textp text_ptr, int num_text));
2398	#endif
2399
2400	/* Note while png_set_text() will accept a structure whose text,
2401	* language, and translated keywords are NULL pointers, the structure
2402	* returned by png_get_text will always contain regular
2403	* zero-terminated C strings. They might be empty strings but
2404	* they will never be NULL pointers.
2405	*/
2406
2407	#ifdef PNG_TEXT_SUPPORTED
2408	extern PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,
2409	png_infop info_ptr, png_textp text_ptr, int num_text));
2410	#endif
2411
2412	#ifdef PNG_tIME_SUPPORTED
2413	extern PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_structp png_ptr,
2414	png_infop info_ptr, png_timep *mod_time));
2415	#endif
2416
2417	#ifdef PNG_tIME_SUPPORTED
2418	extern PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,
2419	png_infop info_ptr, png_timep mod_time));
2420	#endif
2421
2422	#ifdef PNG_tRNS_SUPPORTED
2423	extern PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_structp png_ptr,
2424	png_infop info_ptr, png_bytep trans_alpha, int num_trans,
2425	png_color_16p *trans_color));
2426	#endif
2427
2428	#ifdef PNG_tRNS_SUPPORTED
2429	extern PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,
2430	png_infop info_ptr, png_bytep trans_alpha, int num_trans,
2431	png_color_16p trans_color));
2432	#endif
2433
2434	#ifdef PNG_tRNS_SUPPORTED
2435	#endif
2436
2437	#ifdef PNG_sCAL_SUPPORTED
2438	#ifdef PNG_FLOATING_POINT_SUPPORTED
2439	extern PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_structp png_ptr,
2440	png_infop info_ptr, int unit, double width, double *height));
2441	#else
2442	#ifdef PNG_FIXED_POINT_SUPPORTED
2443	extern PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_structp png_ptr,
2444	png_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));
2445	#endif
2446	#endif
2447	#endif /* PNG_sCAL_SUPPORTED */
2448
2449	#ifdef PNG_sCAL_SUPPORTED
2450	#ifdef PNG_FLOATING_POINT_SUPPORTED
2451	extern PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,
2452	png_infop info_ptr, int unit, double width, double height));
2453	#else
2454	#ifdef PNG_FIXED_POINT_SUPPORTED
2455	extern PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,
2456	png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));
2457	#endif
2458	#endif
2459	#endif /* PNG_sCAL_SUPPORTED \|\| PNG_WRITE_sCAL_SUPPORTED */
2460
2461	#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
2462	/* Provide a list of chunks and how they are to be handled, if the built-in
2463	handling or default unknown chunk handling is not desired. Any chunks not
2464	listed will be handled in the default manner. The IHDR and IEND chunks
2465	must not be listed.
2466	keep = 0: follow default behaviour
2467	= 1: do not keep
2468	= 2: keep only if safe-to-copy
2469	= 3: keep even if unsafe-to-copy
2470	*/
2471	extern PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp
2472	png_ptr, int keep, png_bytep chunk_list, int num_chunks));
2473	PNG_EXPORT(int,png_handle_as_unknown) PNGARG((png_structp png_ptr, png_bytep
2474	chunk_name));
2475	#endif
2476	#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
2477	extern PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,
2478	png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));
2479	extern PNG_EXPORT(void, png_set_unknown_chunk_location)
2480	PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));
2481	extern PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_structp
2482	png_ptr, png_infop info_ptr, png_unknown_chunkpp entries));
2483	#endif
2484
2485	/* Png_free_data() will turn off the "valid" flag for anything it frees.
2486	* If you need to turn it off for a chunk that your application has freed,
2487	* you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
2488	*/
2489	extern PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,
2490	png_infop info_ptr, int mask));
2491
2492	#ifdef PNG_INFO_IMAGE_SUPPORTED
2493	/* The "params" pointer is currently not used and is for future expansion. */
2494	extern PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,
2495	png_infop info_ptr,
2496	int transforms,
2497	png_voidp params));
2498	extern PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,
2499	png_infop info_ptr,
2500	int transforms,
2501	png_voidp params));
2502	#endif
2503
2504	extern PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_structp png_ptr));
2505	extern PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_structp png_ptr));
2506	extern PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_structp
2507	png_ptr));
2508	extern PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_structp png_ptr));
2509
2510	#ifdef PNG_MNG_FEATURES_SUPPORTED
2511	extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
2512	png_ptr, png_uint_32 mng_features_permitted));
2513	#endif
2514
2515	/* For use in png_set_keep_unknown, added to version 1.2.6 */
2516	#define PNG_HANDLE_CHUNK_AS_DEFAULT 0
2517	#define PNG_HANDLE_CHUNK_NEVER 1
2518	#define PNG_HANDLE_CHUNK_IF_SAFE 2
2519	#define PNG_HANDLE_CHUNK_ALWAYS 3
2520
2521	/* Strip the prepended error numbers ("#nnn ") from error and warning
2522	* messages before passing them to the error or warning handler.
2523	*/
2524	#ifdef PNG_ERROR_NUMBERS_SUPPORTED
2525	extern PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp
2526	png_ptr, png_uint_32 strip_mode));
2527	#endif
2528
2529	/* Added in libpng-1.2.6 */
2530	#ifdef PNG_SET_USER_LIMITS_SUPPORTED
2531	extern PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp
2532	png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max));
2533	extern PNG_EXPORT(png_uint_32,png_get_user_width_max) PNGARG((png_structp
2534	png_ptr));
2535	extern PNG_EXPORT(png_uint_32,png_get_user_height_max) PNGARG((png_structp
2536	png_ptr));
2537	/* Added in libpng-1.4.0 */
2538	extern PNG_EXPORT(void,png_set_chunk_cache_max) PNGARG((png_structp
2539	png_ptr, png_uint_32 user_chunk_cache_max));
2540	extern PNG_EXPORT(png_uint_32,png_get_chunk_cache_max)
2541	PNGARG((png_structp png_ptr));
2542	/* Added in libpng-1.4.1 */
2543	extern PNG_EXPORT(void,png_set_chunk_malloc_max) PNGARG((png_structp
2544	png_ptr, png_alloc_size_t user_chunk_cache_max));
2545	extern PNG_EXPORT(png_alloc_size_t,png_get_chunk_malloc_max)
2546	PNGARG((png_structp png_ptr));
2547	#endif
2548
2549	#if defined(PNG_INCH_CONVERSIONS) && defined(PNG_FLOATING_POINT_SUPPORTED)
2550	PNG_EXPORT(png_uint_32,png_get_pixels_per_inch) PNGARG((png_structp png_ptr,
2551	png_infop info_ptr));
2552
2553	PNG_EXPORT(png_uint_32,png_get_x_pixels_per_inch) PNGARG((png_structp png_ptr,
2554	png_infop info_ptr));
2555
2556	PNG_EXPORT(png_uint_32,png_get_y_pixels_per_inch) PNGARG((png_structp png_ptr,
2557	png_infop info_ptr));
2558
2559	PNG_EXPORT(float,png_get_x_offset_inches) PNGARG((png_structp png_ptr,
2560	png_infop info_ptr));
2561
2562	PNG_EXPORT(float,png_get_y_offset_inches) PNGARG((png_structp png_ptr,
2563	png_infop info_ptr));
2564
2565	#ifdef PNG_pHYs_SUPPORTED
2566	PNG_EXPORT(png_uint_32,png_get_pHYs_dpi) PNGARG((png_structp png_ptr,
2567	png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int *unit_type));
2568	#endif /* PNG_pHYs_SUPPORTED */
2569	#endif /* PNG_INCH_CONVERSIONS && PNG_FLOATING_POINT_SUPPORTED */
2570
2571	/* Added in libpng-1.4.0 */
2572	#ifdef PNG_IO_STATE_SUPPORTED
2573	extern PNG_EXPORT(png_uint_32,png_get_io_state) PNGARG((png_structp png_ptr));
2574
2575	extern PNG_EXPORT(png_bytep,png_get_io_chunk_name)
2576	PNGARG((png_structp png_ptr));
2577
2578	/* The flags returned by png_get_io_state() are the following: */
2579	#define PNG_IO_NONE 0x0000 /* no I/O at this moment */
2580	#define PNG_IO_READING 0x0001 /* currently reading */
2581	#define PNG_IO_WRITING 0x0002 /* currently writing */
2582	#define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
2583	#define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
2584	#define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
2585	#define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
2586	#define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
2587	#define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
2588	#endif /* ?PNG_IO_STATE_SUPPORTED */
2589
2590	/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
2591	* defs
2592	*/
2593
2594	#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
2595	/* With these routines we avoid an integer divide, which will be slower on
2596	* most machines. However, it does take more operations than the corresponding
2597	* divide method, so it may be slower on a few RISC systems. There are two
2598	* shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
2599	*
2600	* Note that the rounding factors are NOT supposed to be the same! 128 and
2601	* 32768 are correct for the NODIV code; 127 and 32767 are correct for the
2602	* standard method.
2603	*
2604	* [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
2605	*/
2606
2607	/* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
2608
2609	# define png_composite(composite, fg, alpha, bg) \
2610	{ png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
2611	* (png_uint_16)(alpha) \
2612	+ (png_uint_16)(bg)*(png_uint_16)(255 \
2613	- (png_uint_16)(alpha)) + (png_uint_16)128); \
2614	(composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
2615
2616	# define png_composite_16(composite, fg, alpha, bg) \
2617	{ png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
2618	* (png_uint_32)(alpha) \
2619	+ (png_uint_32)(bg)*(png_uint_32)(65535L \
2620	- (png_uint_32)(alpha)) + (png_uint_32)32768L); \
2621	(composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
2622
2623	#else /* Standard method using integer division */
2624
2625	# define png_composite(composite, fg, alpha, bg) \
2626	(composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \
2627	(png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
2628	(png_uint_16)127) / 255)
2629
2630	# define png_composite_16(composite, fg, alpha, bg) \
2631	(composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
2632	(png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) + \
2633	(png_uint_32)32767) / (png_uint_32)65535L)
2634	#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
2635
2636	#ifdef PNG_USE_READ_MACROS
2637	/* Inline macros to do direct reads of bytes from the input buffer.
2638	* The png_get_int_32() routine assumes we are using two's complement
2639	* format for negative values, which is almost certainly true.
2640	*/
2641	/* We could make special-case BIG_ENDIAN macros that do direct reads here */
2642	# define png_get_uint_32(buf) \
2643	(((png_uint_32)(*(buf)) << 24) + \
2644	((png_uint_32)(*((buf) + 1)) << 16) + \
2645	((png_uint_32)(*((buf) + 2)) << 8) + \
2646	((png_uint_32)(*((buf) + 3))))
2647	# define png_get_uint_16(buf) \
2648	(((png_uint_32)(*(buf)) << 8) + \
2649	((png_uint_32)(*((buf) + 1))))
2650	#ifdef PNG_GET_INT_32_SUPPORTED
2651	# define png_get_int_32(buf) \
2652	(((png_int_32)(*(buf)) << 24) + \
2653	((png_int_32)(*((buf) + 1)) << 16) + \
2654	((png_int_32)(*((buf) + 2)) << 8) + \
2655	((png_int_32)(*((buf) + 3))))
2656	#endif
2657	#else
2658	extern PNG_EXPORT(png_uint_32,png_get_uint_32) PNGARG((png_bytep buf));
2659	extern PNG_EXPORT(png_uint_16,png_get_uint_16) PNGARG((png_bytep buf));
2660	#ifdef PNG_GET_INT_32_SUPPORTED
2661	extern PNG_EXPORT(png_int_32,png_get_int_32) PNGARG((png_bytep buf));
2662	#endif
2663	#endif
2664	extern PNG_EXPORT(png_uint_32,png_get_uint_31)
2665	PNGARG((png_structp png_ptr, png_bytep buf));
2666	/* No png_get_int_16 -- may be added if there's a real need for it. */
2667
2668	/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
2669	extern PNG_EXPORT(void,png_save_uint_32)
2670	PNGARG((png_bytep buf, png_uint_32 i));
2671	extern PNG_EXPORT(void,png_save_int_32)
2672	PNGARG((png_bytep buf, png_int_32 i));
2673
2674	/* Place a 16-bit number into a buffer in PNG byte order.
2675	* The parameter is declared unsigned int, not png_uint_16,
2676	* just to avoid potential problems on pre-ANSI C compilers.
2677	*/
2678	extern PNG_EXPORT(void,png_save_uint_16)
2679	PNGARG((png_bytep buf, unsigned int i));
2680	/* No png_save_int_16 -- may be added if there's a real need for it. */
2681
2682	/* ************************************************************************* */
2683
2684	/* Various modes of operation. Note that after an init, mode is set to
2685	* zero automatically when the structure is created.
2686	*/
2687	#define PNG_HAVE_IHDR 0x01
2688	#define PNG_HAVE_PLTE 0x02
2689	#define PNG_HAVE_IDAT 0x04
2690	#define PNG_AFTER_IDAT 0x08 /* Have complete zlib datastream */
2691	#define PNG_HAVE_IEND 0x10
2692	#define PNG_HAVE_gAMA 0x20
2693	#define PNG_HAVE_cHRM 0x40
2694
2695	#ifdef __cplusplus
2696	}
2697	#endif
2698
2699	#endif /* PNG_VERSION_INFO_ONLY */
2700	/* Do not put anything past this line */
2701	#endif /* PNG_H */

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