pngwrite.c@ 104389

Last change on this file since 104389 was 103316, checked in by vboxsync, 9 months ago
libpng-1.6.42: Applied and adjusted our libpng changes to 1.6.42. bugref:8515
Property svn:eol-style set to `native`
File size: 75.3 KB

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1
2	/* pngwrite.c - general routines to write a PNG file
3	*
4	* Copyright (c) 2018-2024 Cosmin Truta
5	* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6	* Copyright (c) 1996-1997 Andreas Dilger
7	* Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
8	*
9	* This code is released under the libpng license.
10	* For conditions of distribution and use, see the disclaimer
11	* and license in png.h
12	*/
13
14	#include "pngpriv.h"
15	#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
16	# include <errno.h>
17	#endif /* SIMPLIFIED_WRITE_STDIO */
18
19	#ifdef PNG_WRITE_SUPPORTED
20
21	#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
22	/* Write out all the unknown chunks for the current given location */
23	static void
24	write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
25	unsigned int where)
26	{
27	if (info_ptr->unknown_chunks_num != 0)
28	{
29	png_const_unknown_chunkp up;
30
31	png_debug(5, "writing extra chunks");
32
33	for (up = info_ptr->unknown_chunks;
34	up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
35	++up)
36	if ((up->location & where) != 0)
37	{
38	/* If per-chunk unknown chunk handling is enabled use it, otherwise
39	* just write the chunks the application has set.
40	*/
41	#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
42	int keep = png_handle_as_unknown(png_ptr, up->name);
43
44	/* NOTE: this code is radically different from the read side in the
45	* matter of handling an ancillary unknown chunk. In the read side
46	* the default behavior is to discard it, in the code below the default
47	* behavior is to write it. Critical chunks are, however, only
48	* written if explicitly listed or if the default is set to write all
49	* unknown chunks.
50	*
51	* The default handling is also slightly weird - it is not possible to
52	* stop the writing of all unsafe-to-copy chunks!
53	*
54	* TODO: REVIEW: this would seem to be a bug.
55	*/
56	if (keep != PNG_HANDLE_CHUNK_NEVER &&
57	((up->name[3] & 0x20) /* safe-to-copy overrides everything */ \|\|
58	keep == PNG_HANDLE_CHUNK_ALWAYS \|\|
59	(keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
60	png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
61	#endif
62	{
63	/* TODO: review, what is wrong with a zero length unknown chunk? */
64	if (up->size == 0)
65	png_warning(png_ptr, "Writing zero-length unknown chunk");
66
67	png_write_chunk(png_ptr, up->name, up->data, up->size);
68	}
69	}
70	}
71	}
72	#endif /* WRITE_UNKNOWN_CHUNKS */
73
74	/* Writes all the PNG information. This is the suggested way to use the
75	* library. If you have a new chunk to add, make a function to write it,
76	* and put it in the correct location here. If you want the chunk written
77	* after the image data, put it in png_write_end(). I strongly encourage
78	* you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before
79	* writing the chunk, as that will keep the code from breaking if you want
80	* to just write a plain PNG file. If you have long comments, I suggest
81	* writing them in png_write_end(), and compressing them.
82	*/
83	void PNGAPI
84	png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
85	{
86	png_debug(1, "in png_write_info_before_PLTE");
87
88	if (png_ptr == NULL \|\| info_ptr == NULL)
89	return;
90
91	if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
92	{
93	/* Write PNG signature */
94	png_write_sig(png_ptr);
95
96	#ifdef PNG_MNG_FEATURES_SUPPORTED
97	if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
98	png_ptr->mng_features_permitted != 0)
99	{
100	png_warning(png_ptr,
101	"MNG features are not allowed in a PNG datastream");
102	png_ptr->mng_features_permitted = 0;
103	}
104	#endif
105
106	/* Write IHDR information. */
107	png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
108	info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
109	info_ptr->filter_type,
110	#ifdef PNG_WRITE_INTERLACING_SUPPORTED
111	info_ptr->interlace_type
112	#else
113	0
114	#endif
115	);
116
117	/* The rest of these check to see if the valid field has the appropriate
118	* flag set, and if it does, writes the chunk.
119	*
120	* 1.6.0: COLORSPACE support controls the writing of these chunks too, and
121	* the chunks will be written if the WRITE routine is there and
122	* information * is available in the COLORSPACE. (See
123	* png_colorspace_sync_info in png.c for where the valid flags get set.)
124	*
125	* Under certain circumstances the colorspace can be invalidated without
126	* syncing the info_struct 'valid' flags; this happens if libpng detects
127	* an error and calls png_error while the color space is being set, yet
128	* the application continues writing the PNG. So check the 'invalid'
129	* flag here too.
130	*/
131	#ifdef PNG_GAMMA_SUPPORTED
132	# ifdef PNG_WRITE_gAMA_SUPPORTED
133	if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
134	(info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
135	(info_ptr->valid & PNG_INFO_gAMA) != 0)
136	png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
137	# endif
138	#endif
139
140	#ifdef PNG_COLORSPACE_SUPPORTED
141	/* Write only one of sRGB or an ICC profile. If a profile was supplied
142	* and it matches one of the known sRGB ones issue a warning.
143	*/
144	# ifdef PNG_WRITE_iCCP_SUPPORTED
145	if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
146	(info_ptr->valid & PNG_INFO_iCCP) != 0)
147	{
148	# ifdef PNG_WRITE_sRGB_SUPPORTED
149	if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
150	png_app_warning(png_ptr,
151	"profile matches sRGB but writing iCCP instead");
152	# endif
153
154	png_write_iCCP(png_ptr, info_ptr->iccp_name,
155	info_ptr->iccp_profile);
156	}
157	# ifdef PNG_WRITE_sRGB_SUPPORTED
158	else
159	# endif
160	# endif
161
162	# ifdef PNG_WRITE_sRGB_SUPPORTED
163	if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
164	(info_ptr->valid & PNG_INFO_sRGB) != 0)
165	png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
166	# endif /* WRITE_sRGB */
167	#endif /* COLORSPACE */
168
169	#ifdef PNG_WRITE_sBIT_SUPPORTED
170	if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
171	png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
172	#endif
173
174	#ifdef PNG_COLORSPACE_SUPPORTED
175	# ifdef PNG_WRITE_cHRM_SUPPORTED
176	if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
177	(info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
178	(info_ptr->valid & PNG_INFO_cHRM) != 0)
179	png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
180	# endif
181	#endif
182
183	#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
184	write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
185	#endif
186
187	png_ptr->mode \|= PNG_WROTE_INFO_BEFORE_PLTE;
188	}
189	}
190
191	void PNGAPI
192	png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
193	{
194	#if defined(PNG_WRITE_TEXT_SUPPORTED) \|\| defined(PNG_WRITE_sPLT_SUPPORTED)
195	int i;
196	#endif
197
198	png_debug(1, "in png_write_info");
199
200	if (png_ptr == NULL \|\| info_ptr == NULL)
201	return;
202
203	png_write_info_before_PLTE(png_ptr, info_ptr);
204
205	if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
206	png_write_PLTE(png_ptr, info_ptr->palette,
207	(png_uint_32)info_ptr->num_palette);
208
209	else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
210	png_error(png_ptr, "Valid palette required for paletted images");
211
212	#ifdef PNG_WRITE_tRNS_SUPPORTED
213	if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
214	{
215	#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
216	/* Invert the alpha channel (in tRNS) */
217	if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
218	info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
219	{
220	int j, jend;
221
222	jend = info_ptr->num_trans;
223	if (jend > PNG_MAX_PALETTE_LENGTH)
224	jend = PNG_MAX_PALETTE_LENGTH;
225
226	for (j = 0; j<jend; ++j)
227	info_ptr->trans_alpha[j] =
228	(png_byte)(255 - info_ptr->trans_alpha[j]);
229	}
230	#endif
231	png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
232	info_ptr->num_trans, info_ptr->color_type);
233	}
234	#endif
235	#ifdef PNG_WRITE_bKGD_SUPPORTED
236	if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
237	png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
238	#endif
239
240	#ifdef PNG_WRITE_eXIf_SUPPORTED
241	if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
242	{
243	png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
244	png_ptr->mode \|= PNG_WROTE_eXIf;
245	}
246	#endif
247
248	#ifdef PNG_WRITE_hIST_SUPPORTED
249	if ((info_ptr->valid & PNG_INFO_hIST) != 0)
250	png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
251	#endif
252
253	#ifdef PNG_WRITE_oFFs_SUPPORTED
254	if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
255	png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
256	info_ptr->offset_unit_type);
257	#endif
258
259	#ifdef PNG_WRITE_pCAL_SUPPORTED
260	if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
261	png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
262	info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
263	info_ptr->pcal_units, info_ptr->pcal_params);
264	#endif
265
266	#ifdef PNG_WRITE_sCAL_SUPPORTED
267	if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
268	png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
269	info_ptr->scal_s_width, info_ptr->scal_s_height);
270	#endif /* sCAL */
271
272	#ifdef PNG_WRITE_pHYs_SUPPORTED
273	if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
274	png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
275	info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
276	#endif /* pHYs */
277
278	#ifdef PNG_WRITE_tIME_SUPPORTED
279	if ((info_ptr->valid & PNG_INFO_tIME) != 0)
280	{
281	png_write_tIME(png_ptr, &(info_ptr->mod_time));
282	png_ptr->mode \|= PNG_WROTE_tIME;
283	}
284	#endif /* tIME */
285
286	#ifdef PNG_WRITE_sPLT_SUPPORTED
287	if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
288	for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
289	png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
290	#endif /* sPLT */
291
292	#ifdef PNG_WRITE_TEXT_SUPPORTED
293	/* Check to see if we need to write text chunks */
294	for (i = 0; i < info_ptr->num_text; i++)
295	{
296	png_debug2(2, "Writing header text chunk %d, type %d", i,
297	info_ptr->text[i].compression);
298	/* An internationalized chunk? */
299	if (info_ptr->text[i].compression > 0)
300	{
301	#ifdef PNG_WRITE_iTXt_SUPPORTED
302	/* Write international chunk */
303	png_write_iTXt(png_ptr,
304	info_ptr->text[i].compression,
305	info_ptr->text[i].key,
306	info_ptr->text[i].lang,
307	info_ptr->text[i].lang_key,
308	info_ptr->text[i].text);
309	/* Mark this chunk as written */
310	if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
311	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
312	else
313	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
314	#else
315	png_warning(png_ptr, "Unable to write international text");
316	#endif
317	}
318
319	/* If we want a compressed text chunk */
320	else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
321	{
322	#ifdef PNG_WRITE_zTXt_SUPPORTED
323	/* Write compressed chunk */
324	png_write_zTXt(png_ptr, info_ptr->text[i].key,
325	info_ptr->text[i].text, info_ptr->text[i].compression);
326	/* Mark this chunk as written */
327	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
328	#else
329	png_warning(png_ptr, "Unable to write compressed text");
330	#endif
331	}
332
333	else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
334	{
335	#ifdef PNG_WRITE_tEXt_SUPPORTED
336	/* Write uncompressed chunk */
337	png_write_tEXt(png_ptr, info_ptr->text[i].key,
338	info_ptr->text[i].text,
339	0);
340	/* Mark this chunk as written */
341	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
342	#else
343	/* Can't get here */
344	png_warning(png_ptr, "Unable to write uncompressed text");
345	#endif
346	}
347	}
348	#endif /* tEXt */
349
350	#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
351	write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
352	#endif
353	}
354
355	/* Writes the end of the PNG file. If you don't want to write comments or
356	* time information, you can pass NULL for info. If you already wrote these
357	* in png_write_info(), do not write them again here. If you have long
358	* comments, I suggest writing them here, and compressing them.
359	*/
360	void PNGAPI
361	png_write_end(png_structrp png_ptr, png_inforp info_ptr)
362	{
363	png_debug(1, "in png_write_end");
364
365	if (png_ptr == NULL)
366	return;
367
368	if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
369	png_error(png_ptr, "No IDATs written into file");
370
371	#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
372	if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
373	png_ptr->num_palette_max >= png_ptr->num_palette)
374	png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
375	#endif
376
377	/* See if user wants us to write information chunks */
378	if (info_ptr != NULL)
379	{
380	#ifdef PNG_WRITE_TEXT_SUPPORTED
381	int i; /* local index variable */
382	#endif
383	#ifdef PNG_WRITE_tIME_SUPPORTED
384	/* Check to see if user has supplied a time chunk */
385	if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
386	(png_ptr->mode & PNG_WROTE_tIME) == 0)
387	png_write_tIME(png_ptr, &(info_ptr->mod_time));
388
389	#endif
390	#ifdef PNG_WRITE_TEXT_SUPPORTED
391	/* Loop through comment chunks */
392	for (i = 0; i < info_ptr->num_text; i++)
393	{
394	png_debug2(2, "Writing trailer text chunk %d, type %d", i,
395	info_ptr->text[i].compression);
396	/* An internationalized chunk? */
397	if (info_ptr->text[i].compression > 0)
398	{
399	#ifdef PNG_WRITE_iTXt_SUPPORTED
400	/* Write international chunk */
401	png_write_iTXt(png_ptr,
402	info_ptr->text[i].compression,
403	info_ptr->text[i].key,
404	info_ptr->text[i].lang,
405	info_ptr->text[i].lang_key,
406	info_ptr->text[i].text);
407	/* Mark this chunk as written */
408	if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
409	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
410	else
411	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
412	#else
413	png_warning(png_ptr, "Unable to write international text");
414	#endif
415	}
416
417	else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
418	{
419	#ifdef PNG_WRITE_zTXt_SUPPORTED
420	/* Write compressed chunk */
421	png_write_zTXt(png_ptr, info_ptr->text[i].key,
422	info_ptr->text[i].text, info_ptr->text[i].compression);
423	/* Mark this chunk as written */
424	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
425	#else
426	png_warning(png_ptr, "Unable to write compressed text");
427	#endif
428	}
429
430	else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
431	{
432	#ifdef PNG_WRITE_tEXt_SUPPORTED
433	/* Write uncompressed chunk */
434	png_write_tEXt(png_ptr, info_ptr->text[i].key,
435	info_ptr->text[i].text, 0);
436	/* Mark this chunk as written */
437	info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
438	#else
439	png_warning(png_ptr, "Unable to write uncompressed text");
440	#endif
441	}
442	}
443	#endif
444
445	#ifdef PNG_WRITE_eXIf_SUPPORTED
446	if ((info_ptr->valid & PNG_INFO_eXIf) != 0 &&
447	(png_ptr->mode & PNG_WROTE_eXIf) == 0)
448	png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
449	#endif
450
451	#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
452	write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
453	#endif
454	}
455
456	png_ptr->mode \|= PNG_AFTER_IDAT;
457
458	/* Write end of PNG file */
459	png_write_IEND(png_ptr);
460
461	/* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
462	* and restored again in libpng-1.2.30, may cause some applications that
463	* do not set png_ptr->output_flush_fn to crash. If your application
464	* experiences a problem, please try building libpng with
465	* PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
466	* png-mng-implement at lists.sf.net .
467	*/
468	#ifdef PNG_WRITE_FLUSH_SUPPORTED
469	# ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
470	png_flush(png_ptr);
471	# endif
472	#endif
473	}
474
475	#ifdef PNG_CONVERT_tIME_SUPPORTED
476	void PNGAPI
477	png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
478	{
479	png_debug(1, "in png_convert_from_struct_tm");
480
481	ptime->year = (png_uint_16)(1900 + ttime->tm_year);
482	ptime->month = (png_byte)(ttime->tm_mon + 1);
483	ptime->day = (png_byte)ttime->tm_mday;
484	ptime->hour = (png_byte)ttime->tm_hour;
485	ptime->minute = (png_byte)ttime->tm_min;
486	ptime->second = (png_byte)ttime->tm_sec;
487	}
488
489	void PNGAPI
490	png_convert_from_time_t(png_timep ptime, time_t ttime)
491	{
492	struct tm *tbuf;
493
494	png_debug(1, "in png_convert_from_time_t");
495
496	tbuf = gmtime(&ttime);
497	if (tbuf == NULL)
498	{
499	/* TODO: add a safe function which takes a png_ptr argument and raises
500	* a png_error if the ttime argument is invalid and the call to gmtime
501	* fails as a consequence.
502	*/
503	memset(ptime, 0, sizeof(*ptime));
504	return;
505	}
506
507	png_convert_from_struct_tm(ptime, tbuf);
508	}
509	#endif
510
511	/* Initialize png_ptr structure, and allocate any memory needed */
512	PNG_FUNCTION(png_structp,PNGAPI
513	png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
514	png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
515	{
516	#ifndef PNG_USER_MEM_SUPPORTED
517	png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
518	error_fn, warn_fn, NULL, NULL, NULL);
519	#else
520	return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
521	warn_fn, NULL, NULL, NULL);
522	}
523
524	/* Alternate initialize png_ptr structure, and allocate any memory needed */
525	PNG_FUNCTION(png_structp,PNGAPI
526	png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
527	png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
528	png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
529	{
530	png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
531	error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
532	#endif /* USER_MEM */
533	if (png_ptr != NULL)
534	{
535	/* Set the zlib control values to defaults; they can be overridden by the
536	* application after the struct has been created.
537	*/
538	png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
539
540	/* The 'zlib_strategy' setting is irrelevant because png_default_claim in
541	* pngwutil.c defaults it according to whether or not filters will be
542	* used, and ignores this setting.
543	*/
544	png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
545	png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
546	png_ptr->zlib_mem_level = 8;
547	png_ptr->zlib_window_bits = 15;
548	png_ptr->zlib_method = 8;
549
550	#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
551	png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
552	png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
553	png_ptr->zlib_text_mem_level = 8;
554	png_ptr->zlib_text_window_bits = 15;
555	png_ptr->zlib_text_method = 8;
556	#endif /* WRITE_COMPRESSED_TEXT */
557
558	/* This is a highly dubious configuration option; by default it is off,
559	* but it may be appropriate for private builds that are testing
560	* extensions not conformant to the current specification, or of
561	* applications that must not fail to write at all costs!
562	*/
563	#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
564	/* In stable builds only warn if an application error can be completely
565	* handled.
566	*/
567	png_ptr->flags \|= PNG_FLAG_BENIGN_ERRORS_WARN;
568	#endif
569
570	/* App warnings are warnings in release (or release candidate) builds but
571	* are errors during development.
572	*/
573	#if PNG_RELEASE_BUILD
574	png_ptr->flags \|= PNG_FLAG_APP_WARNINGS_WARN;
575	#endif
576
577	/* TODO: delay this, it can be done in png_init_io() (if the app doesn't
578	* do it itself) avoiding setting the default function if it is not
579	* required.
580	*/
581	png_set_write_fn(png_ptr, NULL, NULL, NULL);
582	}
583
584	return png_ptr;
585	}
586
587
588	/* Write a few rows of image data. If the image is interlaced,
589	* either you will have to write the 7 sub images, or, if you
590	* have called png_set_interlace_handling(), you will have to
591	* "write" the image seven times.
592	*/
593	void PNGAPI
594	png_write_rows(png_structrp png_ptr, png_bytepp row,
595	png_uint_32 num_rows)
596	{
597	png_uint_32 i; /* row counter */
598	png_bytepp rp; /* row pointer */
599
600	png_debug(1, "in png_write_rows");
601
602	if (png_ptr == NULL)
603	return;
604
605	/* Loop through the rows */
606	for (i = 0, rp = row; i < num_rows; i++, rp++)
607	{
608	png_write_row(png_ptr, *rp);
609	}
610	}
611
612	/* Write the image. You only need to call this function once, even
613	* if you are writing an interlaced image.
614	*/
615	void PNGAPI
616	png_write_image(png_structrp png_ptr, png_bytepp image)
617	{
618	png_uint_32 i; /* row index */
619	int pass, num_pass; /* pass variables */
620	png_bytepp rp; /* points to current row */
621
622	if (png_ptr == NULL)
623	return;
624
625	png_debug(1, "in png_write_image");
626
627	#ifdef PNG_WRITE_INTERLACING_SUPPORTED
628	/* Initialize interlace handling. If image is not interlaced,
629	* this will set pass to 1
630	*/
631	num_pass = png_set_interlace_handling(png_ptr);
632	#else
633	num_pass = 1;
634	#endif
635	/* Loop through passes */
636	for (pass = 0; pass < num_pass; pass++)
637	{
638	/* Loop through image */
639	for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
640	{
641	png_write_row(png_ptr, *rp);
642	}
643	}
644	}
645
646	#ifdef PNG_MNG_FEATURES_SUPPORTED
647	/* Performs intrapixel differencing */
648	static void
649	png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
650	{
651	png_debug(1, "in png_do_write_intrapixel");
652
653	if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
654	{
655	int bytes_per_pixel;
656	png_uint_32 row_width = row_info->width;
657	if (row_info->bit_depth == 8)
658	{
659	png_bytep rp;
660	png_uint_32 i;
661
662	if (row_info->color_type == PNG_COLOR_TYPE_RGB)
663	bytes_per_pixel = 3;
664
665	else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
666	bytes_per_pixel = 4;
667
668	else
669	return;
670
671	for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
672	{
673	(rp) = (png_byte)(rp - *(rp + 1));
674	(rp + 2) = (png_byte)((rp + 2) - *(rp + 1));
675	}
676	}
677
678	#ifdef PNG_WRITE_16BIT_SUPPORTED
679	else if (row_info->bit_depth == 16)
680	{
681	png_bytep rp;
682	png_uint_32 i;
683
684	if (row_info->color_type == PNG_COLOR_TYPE_RGB)
685	bytes_per_pixel = 6;
686
687	else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
688	bytes_per_pixel = 8;
689
690	else
691	return;
692
693	for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
694	{
695	png_uint_32 s0 = (png_uint_32)((rp ) << 8) \| (rp + 1);
696	png_uint_32 s1 = (png_uint_32)((rp + 2) << 8) \| (rp + 3);
697	png_uint_32 s2 = (png_uint_32)((rp + 4) << 8) \| (rp + 5);
698	png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
699	png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
700	*(rp ) = (png_byte)(red >> 8);
701	*(rp + 1) = (png_byte)red;
702	*(rp + 4) = (png_byte)(blue >> 8);
703	*(rp + 5) = (png_byte)blue;
704	}
705	}
706	#endif /* WRITE_16BIT */
707	}
708	}
709	#endif /* MNG_FEATURES */
710
711	/* Called by user to write a row of image data */
712	void PNGAPI
713	png_write_row(png_structrp png_ptr, png_const_bytep row)
714	{
715	/* 1.5.6: moved from png_struct to be a local structure: */
716	png_row_info row_info;
717
718	png_debug2(1, "in png_write_row (row %u, pass %d)",
719	png_ptr->row_number, png_ptr->pass);
720
721	if (png_ptr == NULL)
722	return;
723
724	/* Initialize transformations and other stuff if first time */
725	if (png_ptr->row_number == 0 && png_ptr->pass == 0)
726	{
727	/* Make sure we wrote the header info */
728	if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
729	png_error(png_ptr,
730	"png_write_info was never called before png_write_row");
731
732	/* Check for transforms that have been set but were defined out */
733	#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
734	if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
735	png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
736	#endif
737
738	#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
739	if ((png_ptr->transformations & PNG_FILLER) != 0)
740	png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
741	#endif
742	#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
743	defined(PNG_READ_PACKSWAP_SUPPORTED)
744	if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
745	png_warning(png_ptr,
746	"PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
747	#endif
748
749	#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
750	if ((png_ptr->transformations & PNG_PACK) != 0)
751	png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
752	#endif
753
754	#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
755	if ((png_ptr->transformations & PNG_SHIFT) != 0)
756	png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
757	#endif
758
759	#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
760	if ((png_ptr->transformations & PNG_BGR) != 0)
761	png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
762	#endif
763
764	#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
765	if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
766	png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
767	#endif
768
769	png_write_start_row(png_ptr);
770	}
771
772	#ifdef PNG_WRITE_INTERLACING_SUPPORTED
773	/* If interlaced and not interested in row, return */
774	if (png_ptr->interlaced != 0 &&
775	(png_ptr->transformations & PNG_INTERLACE) != 0)
776	{
777	switch (png_ptr->pass)
778	{
779	case 0:
780	if ((png_ptr->row_number & 0x07) != 0)
781	{
782	png_write_finish_row(png_ptr);
783	return;
784	}
785	break;
786
787	case 1:
788	if ((png_ptr->row_number & 0x07) != 0 \|\| png_ptr->width < 5)
789	{
790	png_write_finish_row(png_ptr);
791	return;
792	}
793	break;
794
795	case 2:
796	if ((png_ptr->row_number & 0x07) != 4)
797	{
798	png_write_finish_row(png_ptr);
799	return;
800	}
801	break;
802
803	case 3:
804	if ((png_ptr->row_number & 0x03) != 0 \|\| png_ptr->width < 3)
805	{
806	png_write_finish_row(png_ptr);
807	return;
808	}
809	break;
810
811	case 4:
812	if ((png_ptr->row_number & 0x03) != 2)
813	{
814	png_write_finish_row(png_ptr);
815	return;
816	}
817	break;
818
819	case 5:
820	if ((png_ptr->row_number & 0x01) != 0 \|\| png_ptr->width < 2)
821	{
822	png_write_finish_row(png_ptr);
823	return;
824	}
825	break;
826
827	case 6:
828	if ((png_ptr->row_number & 0x01) == 0)
829	{
830	png_write_finish_row(png_ptr);
831	return;
832	}
833	break;
834
835	default: /* error: ignore it */
836	break;
837	}
838	}
839	#endif
840
841	/* Set up row info for transformations */
842	row_info.color_type = png_ptr->color_type;
843	row_info.width = png_ptr->usr_width;
844	row_info.channels = png_ptr->usr_channels;
845	row_info.bit_depth = png_ptr->usr_bit_depth;
846	row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
847	row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
848
849	png_debug1(3, "row_info->color_type = %d", row_info.color_type);
850	png_debug1(3, "row_info->width = %u", row_info.width);
851	png_debug1(3, "row_info->channels = %d", row_info.channels);
852	png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
853	png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
854	png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
855
856	/* Copy user's row into buffer, leaving room for filter byte. */
857	memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
858
859	#ifdef PNG_WRITE_INTERLACING_SUPPORTED
860	/* Handle interlacing */
861	if (png_ptr->interlaced && png_ptr->pass < 6 &&
862	(png_ptr->transformations & PNG_INTERLACE) != 0)
863	{
864	png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
865	/* This should always get caught above, but still ... */
866	if (row_info.width == 0)
867	{
868	png_write_finish_row(png_ptr);
869	return;
870	}
871	}
872	#endif
873
874	#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
875	/* Handle other transformations */
876	if (png_ptr->transformations != 0)
877	png_do_write_transformations(png_ptr, &row_info);
878	#endif
879
880	/* At this point the row_info pixel depth must match the 'transformed' depth,
881	* which is also the output depth.
882	*/
883	if (row_info.pixel_depth != png_ptr->pixel_depth \|\|
884	row_info.pixel_depth != png_ptr->transformed_pixel_depth)
885	png_error(png_ptr, "internal write transform logic error");
886
887	#ifdef PNG_MNG_FEATURES_SUPPORTED
888	/* Write filter_method 64 (intrapixel differencing) only if
889	* 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
890	* 2. Libpng did not write a PNG signature (this filter_method is only
891	* used in PNG datastreams that are embedded in MNG datastreams) and
892	* 3. The application called png_permit_mng_features with a mask that
893	* included PNG_FLAG_MNG_FILTER_64 and
894	* 4. The filter_method is 64 and
895	* 5. The color_type is RGB or RGBA
896	*/
897	if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
898	(png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
899	{
900	/* Intrapixel differencing */
901	png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
902	}
903	#endif
904
905	/* Added at libpng-1.5.10 */
906	#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
907	/* Check for out-of-range palette index */
908	if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
909	png_ptr->num_palette_max >= 0)
910	png_do_check_palette_indexes(png_ptr, &row_info);
911	#endif
912
913	/* Find a filter if necessary, filter the row and write it out. */
914	png_write_find_filter(png_ptr, &row_info);
915
916	if (png_ptr->write_row_fn != NULL)
917	(*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
918	}
919
920	#ifdef PNG_WRITE_FLUSH_SUPPORTED
921	/* Set the automatic flush interval or 0 to turn flushing off */
922	void PNGAPI
923	png_set_flush(png_structrp png_ptr, int nrows)
924	{
925	png_debug(1, "in png_set_flush");
926
927	if (png_ptr == NULL)
928	return;
929
930	png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
931	}
932
933	/* Flush the current output buffers now */
934	void PNGAPI
935	png_write_flush(png_structrp png_ptr)
936	{
937	png_debug(1, "in png_write_flush");
938
939	if (png_ptr == NULL)
940	return;
941
942	/* We have already written out all of the data */
943	if (png_ptr->row_number >= png_ptr->num_rows)
944	return;
945
946	png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
947	png_ptr->flush_rows = 0;
948	png_flush(png_ptr);
949	}
950	#endif /* WRITE_FLUSH */
951
952	/* Free any memory used in png_ptr struct without freeing the struct itself. */
953	static void
954	png_write_destroy(png_structrp png_ptr)
955	{
956	png_debug(1, "in png_write_destroy");
957
958	/* Free any memory zlib uses */
959	if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
960	deflateEnd(&png_ptr->zstream);
961
962	/* Free our memory. png_free checks NULL for us. */
963	png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
964	png_free(png_ptr, png_ptr->row_buf);
965	png_ptr->row_buf = NULL;
966	#ifdef PNG_WRITE_FILTER_SUPPORTED
967	png_free(png_ptr, png_ptr->prev_row);
968	png_free(png_ptr, png_ptr->try_row);
969	png_free(png_ptr, png_ptr->tst_row);
970	png_ptr->prev_row = NULL;
971	png_ptr->try_row = NULL;
972	png_ptr->tst_row = NULL;
973	#endif
974
975	#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
976	png_free(png_ptr, png_ptr->chunk_list);
977	png_ptr->chunk_list = NULL;
978	#endif
979
980	/* The error handling and memory handling information is left intact at this
981	* point: the jmp_buf may still have to be freed. See png_destroy_png_struct
982	* for how this happens.
983	*/
984	}
985
986	/* Free all memory used by the write.
987	* In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
988	* *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
989	* the passed in info_structs but it would quietly fail to free any of the data
990	* inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
991	* has no png_ptr.)
992	*/
993	void PNGAPI
994	png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
995	{
996	png_debug(1, "in png_destroy_write_struct");
997
998	if (png_ptr_ptr != NULL)
999	{
1000	png_structrp png_ptr = *png_ptr_ptr;
1001
1002	if (png_ptr != NULL) /* added in libpng 1.6.0 */
1003	{
1004	png_destroy_info_struct(png_ptr, info_ptr_ptr);
1005
1006	*png_ptr_ptr = NULL;
1007	png_write_destroy(png_ptr);
1008	png_destroy_png_struct(png_ptr);
1009	}
1010	}
1011	}
1012
1013	/* Allow the application to select one or more row filters to use. */
1014	void PNGAPI
1015	png_set_filter(png_structrp png_ptr, int method, int filters)
1016	{
1017	png_debug(1, "in png_set_filter");
1018
1019	if (png_ptr == NULL)
1020	return;
1021
1022	#ifdef PNG_MNG_FEATURES_SUPPORTED
1023	if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
1024	(method == PNG_INTRAPIXEL_DIFFERENCING))
1025	method = PNG_FILTER_TYPE_BASE;
1026
1027	#endif
1028	if (method == PNG_FILTER_TYPE_BASE)
1029	{
1030	switch (filters & (PNG_ALL_FILTERS \| 0x07))
1031	{
1032	#ifdef PNG_WRITE_FILTER_SUPPORTED
1033	case 5:
1034	case 6:
1035	case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1036	#endif /* WRITE_FILTER */
1037	/* FALLTHROUGH */
1038	case PNG_FILTER_VALUE_NONE:
1039	png_ptr->do_filter = PNG_FILTER_NONE; break;
1040
1041	#ifdef PNG_WRITE_FILTER_SUPPORTED
1042	case PNG_FILTER_VALUE_SUB:
1043	png_ptr->do_filter = PNG_FILTER_SUB; break;
1044
1045	case PNG_FILTER_VALUE_UP:
1046	png_ptr->do_filter = PNG_FILTER_UP; break;
1047
1048	case PNG_FILTER_VALUE_AVG:
1049	png_ptr->do_filter = PNG_FILTER_AVG; break;
1050
1051	case PNG_FILTER_VALUE_PAETH:
1052	png_ptr->do_filter = PNG_FILTER_PAETH; break;
1053
1054	default:
1055	png_ptr->do_filter = (png_byte)filters; break;
1056	#else
1057	default:
1058	png_app_error(png_ptr, "Unknown row filter for method 0");
1059	#endif /* WRITE_FILTER */
1060	}
1061
1062	#ifdef PNG_WRITE_FILTER_SUPPORTED
1063	/* If we have allocated the row_buf, this means we have already started
1064	* with the image and we should have allocated all of the filter buffers
1065	* that have been selected. If prev_row isn't already allocated, then
1066	* it is too late to start using the filters that need it, since we
1067	* will be missing the data in the previous row. If an application
1068	* wants to start and stop using particular filters during compression,
1069	* it should start out with all of the filters, and then remove them
1070	* or add them back after the start of compression.
1071	*
1072	* NOTE: this is a nasty constraint on the code, because it means that the
1073	* prev_row buffer must be maintained even if there are currently no
1074	* 'prev_row' requiring filters active.
1075	*/
1076	if (png_ptr->row_buf != NULL)
1077	{
1078	int num_filters;
1079	png_alloc_size_t buf_size;
1080
1081	/* Repeat the checks in png_write_start_row; 1 pixel high or wide
1082	* images cannot benefit from certain filters. If this isn't done here
1083	* the check below will fire on 1 pixel high images.
1084	*/
1085	if (png_ptr->height == 1)
1086	filters &= ~(PNG_FILTER_UP\|PNG_FILTER_AVG\|PNG_FILTER_PAETH);
1087
1088	if (png_ptr->width == 1)
1089	filters &= ~(PNG_FILTER_SUB\|PNG_FILTER_AVG\|PNG_FILTER_PAETH);
1090
1091	if ((filters & (PNG_FILTER_UP\|PNG_FILTER_AVG\|PNG_FILTER_PAETH)) != 0
1092	&& png_ptr->prev_row == NULL)
1093	{
1094	/* This is the error case, however it is benign - the previous row
1095	* is not available so the filter can't be used. Just warn here.
1096	*/
1097	png_app_warning(png_ptr,
1098	"png_set_filter: UP/AVG/PAETH cannot be added after start");
1099	filters &= ~(PNG_FILTER_UP\|PNG_FILTER_AVG\|PNG_FILTER_PAETH);
1100	}
1101
1102	num_filters = 0;
1103
1104	if (filters & PNG_FILTER_SUB)
1105	num_filters++;
1106
1107	if (filters & PNG_FILTER_UP)
1108	num_filters++;
1109
1110	if (filters & PNG_FILTER_AVG)
1111	num_filters++;
1112
1113	if (filters & PNG_FILTER_PAETH)
1114	num_filters++;
1115
1116	/* Allocate needed row buffers if they have not already been
1117	* allocated.
1118	*/
1119	buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1120	png_ptr->width) + 1;
1121
1122	if (png_ptr->try_row == NULL)
1123	png_ptr->try_row = png_voidcast(png_bytep,
1124	png_malloc(png_ptr, buf_size));
1125
1126	if (num_filters > 1)
1127	{
1128	if (png_ptr->tst_row == NULL)
1129	png_ptr->tst_row = png_voidcast(png_bytep,
1130	png_malloc(png_ptr, buf_size));
1131	}
1132	}
1133	png_ptr->do_filter = (png_byte)filters;
1134	#endif
1135	}
1136	else
1137	png_error(png_ptr, "Unknown custom filter method");
1138	}
1139
1140	#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1141	/* Provide floating and fixed point APIs */
1142	#ifdef PNG_FLOATING_POINT_SUPPORTED
1143	void PNGAPI
1144	png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1145	int num_weights, png_const_doublep filter_weights,
1146	png_const_doublep filter_costs)
1147	{
1148	PNG_UNUSED(png_ptr)
1149	PNG_UNUSED(heuristic_method)
1150	PNG_UNUSED(num_weights)
1151	PNG_UNUSED(filter_weights)
1152	PNG_UNUSED(filter_costs)
1153	}
1154	#endif /* FLOATING_POINT */
1155
1156	#ifdef PNG_FIXED_POINT_SUPPORTED
1157	void PNGAPI
1158	png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1159	int num_weights, png_const_fixed_point_p filter_weights,
1160	png_const_fixed_point_p filter_costs)
1161	{
1162	PNG_UNUSED(png_ptr)
1163	PNG_UNUSED(heuristic_method)
1164	PNG_UNUSED(num_weights)
1165	PNG_UNUSED(filter_weights)
1166	PNG_UNUSED(filter_costs)
1167	}
1168	#endif /* FIXED_POINT */
1169	#endif /* WRITE_WEIGHTED_FILTER */
1170
1171	#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1172	void PNGAPI
1173	png_set_compression_level(png_structrp png_ptr, int level)
1174	{
1175	png_debug(1, "in png_set_compression_level");
1176
1177	if (png_ptr == NULL)
1178	return;
1179
1180	png_ptr->zlib_level = level;
1181	}
1182
1183	void PNGAPI
1184	png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1185	{
1186	png_debug(1, "in png_set_compression_mem_level");
1187
1188	if (png_ptr == NULL)
1189	return;
1190
1191	png_ptr->zlib_mem_level = mem_level;
1192	}
1193
1194	void PNGAPI
1195	png_set_compression_strategy(png_structrp png_ptr, int strategy)
1196	{
1197	png_debug(1, "in png_set_compression_strategy");
1198
1199	if (png_ptr == NULL)
1200	return;
1201
1202	/* The flag setting here prevents the libpng dynamic selection of strategy.
1203	*/
1204	png_ptr->flags \|= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1205	png_ptr->zlib_strategy = strategy;
1206	}
1207
1208	/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1209	* smaller value of window_bits if it can do so safely.
1210	*/
1211	void PNGAPI
1212	png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1213	{
1214	png_debug(1, "in png_set_compression_window_bits");
1215
1216	if (png_ptr == NULL)
1217	return;
1218
1219	/* Prior to 1.6.0 this would warn but then set the window_bits value. This
1220	* meant that negative window bits values could be selected that would cause
1221	* libpng to write a non-standard PNG file with raw deflate or gzip
1222	* compressed IDAT or ancillary chunks. Such files can be read and there is
1223	* no warning on read, so this seems like a very bad idea.
1224	*/
1225	if (window_bits > 15)
1226	{
1227	png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1228	window_bits = 15;
1229	}
1230
1231	else if (window_bits < 8)
1232	{
1233	png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1234	window_bits = 8;
1235	}
1236
1237	png_ptr->zlib_window_bits = window_bits;
1238	}
1239
1240	void PNGAPI
1241	png_set_compression_method(png_structrp png_ptr, int method)
1242	{
1243	png_debug(1, "in png_set_compression_method");
1244
1245	if (png_ptr == NULL)
1246	return;
1247
1248	/* This would produce an invalid PNG file if it worked, but it doesn't and
1249	* deflate will fault it, so it is harmless to just warn here.
1250	*/
1251	if (method != 8)
1252	png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1253
1254	png_ptr->zlib_method = method;
1255	}
1256	#endif /* WRITE_CUSTOMIZE_COMPRESSION */
1257
1258	/* The following were added to libpng-1.5.4 */
1259	#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1260	void PNGAPI
1261	png_set_text_compression_level(png_structrp png_ptr, int level)
1262	{
1263	png_debug(1, "in png_set_text_compression_level");
1264
1265	if (png_ptr == NULL)
1266	return;
1267
1268	png_ptr->zlib_text_level = level;
1269	}
1270
1271	void PNGAPI
1272	png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1273	{
1274	png_debug(1, "in png_set_text_compression_mem_level");
1275
1276	if (png_ptr == NULL)
1277	return;
1278
1279	png_ptr->zlib_text_mem_level = mem_level;
1280	}
1281
1282	void PNGAPI
1283	png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1284	{
1285	png_debug(1, "in png_set_text_compression_strategy");
1286
1287	if (png_ptr == NULL)
1288	return;
1289
1290	png_ptr->zlib_text_strategy = strategy;
1291	}
1292
1293	/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1294	* smaller value of window_bits if it can do so safely.
1295	*/
1296	void PNGAPI
1297	png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1298	{
1299	png_debug(1, "in png_set_text_compression_window_bits");
1300
1301	if (png_ptr == NULL)
1302	return;
1303
1304	if (window_bits > 15)
1305	{
1306	png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1307	window_bits = 15;
1308	}
1309
1310	else if (window_bits < 8)
1311	{
1312	png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1313	window_bits = 8;
1314	}
1315
1316	png_ptr->zlib_text_window_bits = window_bits;
1317	}
1318
1319	void PNGAPI
1320	png_set_text_compression_method(png_structrp png_ptr, int method)
1321	{
1322	png_debug(1, "in png_set_text_compression_method");
1323
1324	if (png_ptr == NULL)
1325	return;
1326
1327	if (method != 8)
1328	png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1329
1330	png_ptr->zlib_text_method = method;
1331	}
1332	#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1333	/* end of API added to libpng-1.5.4 */
1334
1335	void PNGAPI
1336	png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1337	{
1338	png_debug(1, "in png_set_write_status_fn");
1339
1340	if (png_ptr == NULL)
1341	return;
1342
1343	png_ptr->write_row_fn = write_row_fn;
1344	}
1345
1346	#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1347	void PNGAPI
1348	png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1349	write_user_transform_fn)
1350	{
1351	png_debug(1, "in png_set_write_user_transform_fn");
1352
1353	if (png_ptr == NULL)
1354	return;
1355
1356	png_ptr->transformations \|= PNG_USER_TRANSFORM;
1357	png_ptr->write_user_transform_fn = write_user_transform_fn;
1358	}
1359	#endif
1360
1361
1362	#ifdef PNG_INFO_IMAGE_SUPPORTED
1363	void PNGAPI
1364	png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1365	int transforms, voidp params)
1366	{
1367	png_debug(1, "in png_write_png");
1368
1369	if (png_ptr == NULL \|\| info_ptr == NULL)
1370	return;
1371
1372	if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1373	{
1374	png_app_error(png_ptr, "no rows for png_write_image to write");
1375	return;
1376	}
1377
1378	/* Write the file header information. */
1379	png_write_info(png_ptr, info_ptr);
1380
1381	/* ------ these transformations don't touch the info structure ------- */
1382
1383	/* Invert monochrome pixels */
1384	if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1385	#ifdef PNG_WRITE_INVERT_SUPPORTED
1386	png_set_invert_mono(png_ptr);
1387	#else
1388	png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1389	#endif
1390
1391	/* Shift the pixels up to a legal bit depth and fill in
1392	* as appropriate to correctly scale the image.
1393	*/
1394	if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1395	#ifdef PNG_WRITE_SHIFT_SUPPORTED
1396	if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1397	png_set_shift(png_ptr, &info_ptr->sig_bit);
1398	#else
1399	png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1400	#endif
1401
1402	/* Pack pixels into bytes */
1403	if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1404	#ifdef PNG_WRITE_PACK_SUPPORTED
1405	png_set_packing(png_ptr);
1406	#else
1407	png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1408	#endif
1409
1410	/* Swap location of alpha bytes from ARGB to RGBA */
1411	if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1412	#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1413	png_set_swap_alpha(png_ptr);
1414	#else
1415	png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1416	#endif
1417
1418	/* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1419	* RGB, note that the code expects the input color type to be G or RGB; no
1420	* alpha channel.
1421	*/
1422	if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER\|
1423	PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1424	{
1425	#ifdef PNG_WRITE_FILLER_SUPPORTED
1426	if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1427	{
1428	if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1429	png_app_error(png_ptr,
1430	"PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1431
1432	/* Continue if ignored - this is the pre-1.6.10 behavior */
1433	png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1434	}
1435
1436	else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1437	png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1438	#else
1439	png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1440	#endif
1441	}
1442
1443	/* Flip BGR pixels to RGB */
1444	if ((transforms & PNG_TRANSFORM_BGR) != 0)
1445	#ifdef PNG_WRITE_BGR_SUPPORTED
1446	png_set_bgr(png_ptr);
1447	#else
1448	png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1449	#endif
1450
1451	/* Swap bytes of 16-bit files to most significant byte first */
1452	if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1453	#ifdef PNG_WRITE_SWAP_SUPPORTED
1454	png_set_swap(png_ptr);
1455	#else
1456	png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1457	#endif
1458
1459	/* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1460	if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1461	#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1462	png_set_packswap(png_ptr);
1463	#else
1464	png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1465	#endif
1466
1467	/* Invert the alpha channel from opacity to transparency */
1468	if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1469	#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1470	png_set_invert_alpha(png_ptr);
1471	#else
1472	png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1473	#endif
1474
1475	/* ----------------------- end of transformations ------------------- */
1476
1477	/* Write the bits */
1478	png_write_image(png_ptr, info_ptr->row_pointers);
1479
1480	/* It is REQUIRED to call this to finish writing the rest of the file */
1481	png_write_end(png_ptr, info_ptr);
1482
1483	PNG_UNUSED(params)
1484	}
1485	#endif
1486
1487
1488	#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1489	/* Initialize the write structure - general purpose utility. */
1490	static int
1491	png_image_write_init(png_imagep image)
1492	{
1493	png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1494	png_safe_error, png_safe_warning);
1495
1496	if (png_ptr != NULL)
1497	{
1498	png_infop info_ptr = png_create_info_struct(png_ptr);
1499
1500	if (info_ptr != NULL)
1501	{
1502	png_controlp control = png_voidcast(png_controlp,
1503	png_malloc_warn(png_ptr, (sizeof *control)));
1504
1505	if (control != NULL)
1506	{
1507	memset(control, 0, (sizeof *control));
1508
1509	control->png_ptr = png_ptr;
1510	control->info_ptr = info_ptr;
1511	control->for_write = 1;
1512
1513	image->opaque = control;
1514	return 1;
1515	}
1516
1517	/* Error clean up */
1518	png_destroy_info_struct(png_ptr, &info_ptr);
1519	}
1520
1521	png_destroy_write_struct(&png_ptr, NULL);
1522	}
1523
1524	return png_image_error(image, "png_image_write_: out of memory");
1525	}
1526
1527	/* Arguments to png_image_write_main: */
1528	typedef struct
1529	{
1530	/* Arguments: */
1531	png_imagep image;
1532	png_const_voidp buffer;
1533	png_int_32 row_stride;
1534	png_const_voidp colormap;
1535	int convert_to_8bit;
1536	/* Local variables: */
1537	png_const_voidp first_row;
1538	ptrdiff_t row_bytes;
1539	png_voidp local_row;
1540	/* Byte count for memory writing */
1541	png_bytep memory;
1542	png_alloc_size_t memory_bytes; /* not used for STDIO */
1543	png_alloc_size_t output_bytes; /* running total */
1544	} png_image_write_control;
1545
1546	/* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1547	* do any necessary byte swapping. The component order is defined by the
1548	* png_image format value.
1549	*/
1550	static int
1551	png_write_image_16bit(png_voidp argument)
1552	{
1553	png_image_write_control display = png_voidcast(png_image_write_control,
1554	argument);
1555	png_imagep image = display->image;
1556	png_structrp png_ptr = image->opaque->png_ptr;
1557
1558	png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1559	display->first_row);
1560	png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1561	png_uint_16p row_end;
1562	unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1563	3 : 1;
1564	int aindex = 0;
1565	png_uint_32 y = image->height;
1566
1567	if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1568	{
1569	# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1570	if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1571	{
1572	aindex = -1;
1573	++input_row; /* To point to the first component */
1574	++output_row;
1575	}
1576	else
1577	aindex = (int)channels;
1578	# else
1579	aindex = (int)channels;
1580	# endif
1581	}
1582
1583	else
1584	png_error(png_ptr, "png_write_image: internal call error");
1585
1586	/* Work out the output row end and count over this, note that the increment
1587	* above to 'row' means that row_end can actually be beyond the end of the
1588	* row; this is correct.
1589	*/
1590	row_end = output_row + image->width * (channels+1);
1591
1592	for (; y > 0; --y)
1593	{
1594	png_const_uint_16p in_ptr = input_row;
1595	png_uint_16p out_ptr = output_row;
1596
1597	while (out_ptr < row_end)
1598	{
1599	png_uint_16 alpha = in_ptr[aindex];
1600	png_uint_32 reciprocal = 0;
1601	int c;
1602
1603	out_ptr[aindex] = alpha;
1604
1605	/* Calculate a reciprocal. The correct calculation is simply
1606	* component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1607	* allows correct rounding by adding .5 before the shift. 'reciprocal'
1608	* is only initialized when required.
1609	*/
1610	if (alpha > 0 && alpha < 65535)
1611	reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1612
1613	c = (int)channels;
1614	do /* always at least one channel */
1615	{
1616	png_uint_16 component = *in_ptr++;
1617
1618	/* The following gives 65535 for an alpha of 0, which is fine,
1619	* otherwise if 0/0 is represented as some other value there is more
1620	* likely to be a discontinuity which will probably damage
1621	* compression when moving from a fully transparent area to a
1622	* nearly transparent one. (The assumption here is that opaque
1623	* areas tend not to be 0 intensity.)
1624	*/
1625	if (component >= alpha)
1626	component = 65535;
1627
1628	/* component<alpha, so component/alpha is less than one and
1629	* component*reciprocal is less than 2^31.
1630	*/
1631	else if (component > 0 && alpha < 65535)
1632	{
1633	png_uint_32 calc = component * reciprocal;
1634	calc += 16384; /* round to nearest */
1635	component = (png_uint_16)(calc >> 15);
1636	}
1637
1638	*out_ptr++ = component;
1639	}
1640	while (--c > 0);
1641
1642	/* Skip to next component (skip the intervening alpha channel) */
1643	++in_ptr;
1644	++out_ptr;
1645	}
1646
1647	png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1648	input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1649	}
1650
1651	return 1;
1652	}
1653
1654	/* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1655	* is present it must be removed from the components, the components are then
1656	* written in sRGB encoding. No components are added or removed.
1657	*
1658	* Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1659	* calculation can be done to 15 bits of accuracy; however, the output needs to
1660	* be scaled in the range 0..255*65535, so include that scaling here.
1661	*/
1662	# define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1663
1664	static png_byte
1665	png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1666	png_uint_32 reciprocal/from the above macro/)
1667	{
1668	/* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1669	* is represented as some other value there is more likely to be a
1670	* discontinuity which will probably damage compression when moving from a
1671	* fully transparent area to a nearly transparent one. (The assumption here
1672	* is that opaque areas tend not to be 0 intensity.)
1673	*
1674	* There is a rounding problem here; if alpha is less than 128 it will end up
1675	* as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1676	* output change for this too.
1677	*/
1678	if (component >= alpha \|\| alpha < 128)
1679	return 255;
1680
1681	/* component<alpha, so component/alpha is less than one and
1682	* component*reciprocal is less than 2^31.
1683	*/
1684	else if (component > 0)
1685	{
1686	/* The test is that alpha/257 (rounded) is less than 255, the first value
1687	* that becomes 255 is 65407.
1688	* NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1689	* be exact!) [Could also test reciprocal != 0]
1690	*/
1691	if (alpha < 65407)
1692	{
1693	component *= reciprocal;
1694	component += 64; /* round to nearest */
1695	component >>= 7;
1696	}
1697
1698	else
1699	component *= 255;
1700
1701	/* Convert the component to sRGB. */
1702	return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1703	}
1704
1705	else
1706	return 0;
1707	}
1708
1709	static int
1710	png_write_image_8bit(png_voidp argument)
1711	{
1712	png_image_write_control display = png_voidcast(png_image_write_control,
1713	argument);
1714	png_imagep image = display->image;
1715	png_structrp png_ptr = image->opaque->png_ptr;
1716
1717	png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1718	display->first_row);
1719	png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1720	png_uint_32 y = image->height;
1721	unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1722	3 : 1;
1723
1724	if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1725	{
1726	png_bytep row_end;
1727	int aindex;
1728
1729	# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1730	if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1731	{
1732	aindex = -1;
1733	++input_row; /* To point to the first component */
1734	++output_row;
1735	}
1736
1737	else
1738	# endif
1739	aindex = (int)channels;
1740
1741	/* Use row_end in place of a loop counter: */
1742	row_end = output_row + image->width * (channels+1);
1743
1744	for (; y > 0; --y)
1745	{
1746	png_const_uint_16p in_ptr = input_row;
1747	png_bytep out_ptr = output_row;
1748
1749	while (out_ptr < row_end)
1750	{
1751	png_uint_16 alpha = in_ptr[aindex];
1752	png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1753	png_uint_32 reciprocal = 0;
1754	int c;
1755
1756	/* Scale and write the alpha channel. */
1757	out_ptr[aindex] = alphabyte;
1758
1759	if (alphabyte > 0 && alphabyte < 255)
1760	reciprocal = UNP_RECIPROCAL(alpha);
1761
1762	c = (int)channels;
1763	do /* always at least one channel */
1764	out_ptr++ = png_unpremultiply(in_ptr++, alpha, reciprocal);
1765	while (--c > 0);
1766
1767	/* Skip to next component (skip the intervening alpha channel) */
1768	++in_ptr;
1769	++out_ptr;
1770	} /* while out_ptr < row_end */
1771
1772	png_write_row(png_ptr, png_voidcast(png_const_bytep,
1773	display->local_row));
1774	input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1775	} /* while y */
1776	}
1777
1778	else
1779	{
1780	/* No alpha channel, so the row_end really is the end of the row and it
1781	* is sufficient to loop over the components one by one.
1782	*/
1783	png_bytep row_end = output_row + image->width * channels;
1784
1785	for (; y > 0; --y)
1786	{
1787	png_const_uint_16p in_ptr = input_row;
1788	png_bytep out_ptr = output_row;
1789
1790	while (out_ptr < row_end)
1791	{
1792	png_uint_32 component = *in_ptr++;
1793
1794	component *= 255;
1795	*out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1796	}
1797
1798	png_write_row(png_ptr, output_row);
1799	input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1800	}
1801	}
1802
1803	return 1;
1804	}
1805
1806	static void
1807	png_image_set_PLTE(png_image_write_control *display)
1808	{
1809	png_imagep image = display->image;
1810	const void *cmap = display->colormap;
1811	int entries = image->colormap_entries > 256 ? 256 :
1812	(int)image->colormap_entries;
1813
1814	/* NOTE: the caller must check for cmap != NULL and entries != 0 */
1815	png_uint_32 format = image->format;
1816	unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1817
1818	# if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1819	defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1820	int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1821	(format & PNG_FORMAT_FLAG_ALPHA) != 0;
1822	# else
1823	# define afirst 0
1824	# endif
1825
1826	# ifdef PNG_FORMAT_BGR_SUPPORTED
1827	int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1828	# else
1829	# define bgr 0
1830	# endif
1831
1832	int i, num_trans;
1833	png_color palette[256];
1834	png_byte tRNS[256];
1835
1836	memset(tRNS, 255, (sizeof tRNS));
1837	memset(palette, 0, (sizeof palette));
1838
1839	for (i=num_trans=0; i<entries; ++i)
1840	{
1841	/* This gets automatically converted to sRGB with reversal of the
1842	* pre-multiplication if the color-map has an alpha channel.
1843	*/
1844	if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1845	{
1846	png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1847
1848	entry += (unsigned int)i * channels;
1849
1850	if ((channels & 1) != 0) /* no alpha */
1851	{
1852	if (channels >= 3) /* RGB */
1853	{
1854	palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1855	entry[(2 ^ bgr)]);
1856	palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1857	entry[1]);
1858	palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1859	entry[bgr]);
1860	}
1861
1862	else /* Gray */
1863	palette[i].blue = palette[i].red = palette[i].green =
1864	(png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1865	}
1866
1867	else /* alpha */
1868	{
1869	png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1870	png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1871	png_uint_32 reciprocal = 0;
1872
1873	/* Calculate a reciprocal, as in the png_write_image_8bit code above
1874	* this is designed to produce a value scaled to 255*65535 when
1875	* divided by 128 (i.e. asr 7).
1876	*/
1877	if (alphabyte > 0 && alphabyte < 255)
1878	reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1879
1880	tRNS[i] = alphabyte;
1881	if (alphabyte < 255)
1882	num_trans = i+1;
1883
1884	if (channels >= 3) /* RGB */
1885	{
1886	palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1887	alpha, reciprocal);
1888	palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1889	reciprocal);
1890	palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1891	reciprocal);
1892	}
1893
1894	else /* gray */
1895	palette[i].blue = palette[i].red = palette[i].green =
1896	png_unpremultiply(entry[afirst], alpha, reciprocal);
1897	}
1898	}
1899
1900	else /* Color-map has sRGB values */
1901	{
1902	png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1903
1904	entry += (unsigned int)i * channels;
1905
1906	switch (channels)
1907	{
1908	case 4:
1909	tRNS[i] = entry[afirst ? 0 : 3];
1910	if (tRNS[i] < 255)
1911	num_trans = i+1;
1912	/* FALLTHROUGH */
1913	case 3:
1914	palette[i].blue = entry[afirst + (2 ^ bgr)];
1915	palette[i].green = entry[afirst + 1];
1916	palette[i].red = entry[afirst + bgr];
1917	break;
1918
1919	case 2:
1920	tRNS[i] = entry[1 ^ afirst];
1921	if (tRNS[i] < 255)
1922	num_trans = i+1;
1923	/* FALLTHROUGH */
1924	case 1:
1925	palette[i].blue = palette[i].red = palette[i].green =
1926	entry[afirst];
1927	break;
1928
1929	default:
1930	break;
1931	}
1932	}
1933	}
1934
1935	# ifdef afirst
1936	# undef afirst
1937	# endif
1938	# ifdef bgr
1939	# undef bgr
1940	# endif
1941
1942	png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
1943	entries);
1944
1945	if (num_trans > 0)
1946	png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
1947	num_trans, NULL);
1948
1949	image->colormap_entries = (png_uint_32)entries;
1950	}
1951
1952	static int
1953	png_image_write_main(png_voidp argument)
1954	{
1955	png_image_write_control display = png_voidcast(png_image_write_control,
1956	argument);
1957	png_imagep image = display->image;
1958	png_structrp png_ptr = image->opaque->png_ptr;
1959	png_inforp info_ptr = image->opaque->info_ptr;
1960	png_uint_32 format = image->format;
1961
1962	/* The following four ints are actually booleans */
1963	int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
1964	int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
1965	int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
1966	int write_16bit = linear && (display->convert_to_8bit == 0);
1967
1968	# ifdef PNG_BENIGN_ERRORS_SUPPORTED
1969	/* Make sure we error out on any bad situation */
1970	png_set_benign_errors(png_ptr, 0/error/);
1971	# endif
1972
1973	/* Default the 'row_stride' parameter if required, also check the row stride
1974	* and total image size to ensure that they are within the system limits.
1975	*/
1976	{
1977	unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
1978
1979	if (image->width <= 0x7fffffffU/channels) /* no overflow */
1980	{
1981	png_uint_32 check;
1982	png_uint_32 png_row_stride = image->width * channels;
1983
1984	if (display->row_stride == 0)
1985	display->row_stride = (png_int_32)/SAFE/png_row_stride;
1986
1987	if (display->row_stride < 0)
1988	check = (png_uint_32)(-display->row_stride);
1989
1990	else
1991	check = (png_uint_32)display->row_stride;
1992
1993	if (check >= png_row_stride)
1994	{
1995	/* Now check for overflow of the image buffer calculation; this
1996	* limits the whole image size to 32 bits for API compatibility with
1997	* the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
1998	*/
1999	if (image->height > 0xffffffffU/png_row_stride)
2000	png_error(image->opaque->png_ptr, "memory image too large");
2001	}
2002
2003	else
2004	png_error(image->opaque->png_ptr, "supplied row stride too small");
2005	}
2006
2007	else
2008	png_error(image->opaque->png_ptr, "image row stride too large");
2009	}
2010
2011	/* Set the required transforms then write the rows in the correct order. */
2012	if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
2013	{
2014	if (display->colormap != NULL && image->colormap_entries > 0)
2015	{
2016	png_uint_32 entries = image->colormap_entries;
2017
2018	png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2019	entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
2020	PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
2021	PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2022
2023	png_image_set_PLTE(display);
2024	}
2025
2026	else
2027	png_error(image->opaque->png_ptr,
2028	"no color-map for color-mapped image");
2029	}
2030
2031	else
2032	png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2033	write_16bit ? 16 : 8,
2034	((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2035	((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2036	PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2037
2038	/* Counter-intuitively the data transformations must be called after
2039	* png_write_info, not before as in the read code, but the 'set' functions
2040	* must still be called before. Just set the color space information, never
2041	* write an interlaced image.
2042	*/
2043
2044	if (write_16bit != 0)
2045	{
2046	/* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2047	png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2048
2049	if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2050	png_set_cHRM_fixed(png_ptr, info_ptr,
2051	/* color x y */
2052	/* white */ 31270, 32900,
2053	/* red */ 64000, 33000,
2054	/* green */ 30000, 60000,
2055	/* blue */ 15000, 6000
2056	);
2057	}
2058
2059	else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2060	png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2061
2062	/* Else writing an 8-bit file and the colors aren't sRGB, but the 8-bit
2063	* space must still be gamma encoded.
2064	*/
2065	else
2066	png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2067
2068	/* Write the file header. */
2069	png_write_info(png_ptr, info_ptr);
2070
2071	/* Now set up the data transformations (after the header is written),
2072	* remove the handled transformations from the 'format' flags for checking.
2073	*
2074	* First check for a little endian system if writing 16-bit files.
2075	*/
2076	if (write_16bit != 0)
2077	{
2078	png_uint_16 le = 0x0001;
2079
2080	if ((*(png_const_bytep) & le) != 0)
2081	png_set_swap(png_ptr);
2082	}
2083
2084	# ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2085	if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2086	{
2087	if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2088	png_set_bgr(png_ptr);
2089	format &= ~PNG_FORMAT_FLAG_BGR;
2090	}
2091	# endif
2092
2093	# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2094	if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2095	{
2096	if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2097	png_set_swap_alpha(png_ptr);
2098	format &= ~PNG_FORMAT_FLAG_AFIRST;
2099	}
2100	# endif
2101
2102	/* If there are 16 or fewer color-map entries we wrote a lower bit depth
2103	* above, but the application data is still byte packed.
2104	*/
2105	if (colormap != 0 && image->colormap_entries <= 16)
2106	png_set_packing(png_ptr);
2107
2108	/* That should have handled all (both) the transforms. */
2109	if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR \| PNG_FORMAT_FLAG_LINEAR \|
2110	PNG_FORMAT_FLAG_ALPHA \| PNG_FORMAT_FLAG_COLORMAP)) != 0)
2111	png_error(png_ptr, "png_write_image: unsupported transformation");
2112
2113	{
2114	png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2115	ptrdiff_t row_bytes = display->row_stride;
2116
2117	if (linear != 0)
2118	row_bytes *= (sizeof (png_uint_16));
2119
2120	if (row_bytes < 0)
2121	row += (image->height-1) * (-row_bytes);
2122
2123	display->first_row = row;
2124	display->row_bytes = row_bytes;
2125	}
2126
2127	/* Apply 'fast' options if the flag is set. */
2128	if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2129	{
2130	png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2131	/* NOTE: determined by experiment using pngstest, this reflects some
2132	* balance between the time to write the image once and the time to read
2133	* it about 50 times. The speed-up in pngstest was about 10-20% of the
2134	* total (user) time on a heavily loaded system.
2135	*/
2136	# ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2137	png_set_compression_level(png_ptr, 3);
2138	# endif
2139	}
2140
2141	/* Check for the cases that currently require a pre-transform on the row
2142	* before it is written. This only applies when the input is 16-bit and
2143	* either there is an alpha channel or it is converted to 8-bit.
2144	*/
2145	if ((linear != 0 && alpha != 0 ) \|\|
2146	(colormap == 0 && display->convert_to_8bit != 0))
2147	{
2148	png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2149	png_get_rowbytes(png_ptr, info_ptr)));
2150	int result;
2151
2152	display->local_row = row;
2153	if (write_16bit != 0)
2154	result = png_safe_execute(image, png_write_image_16bit, display);
2155	else
2156	result = png_safe_execute(image, png_write_image_8bit, display);
2157	display->local_row = NULL;
2158
2159	png_free(png_ptr, row);
2160
2161	/* Skip the 'write_end' on error: */
2162	if (result == 0)
2163	return 0;
2164	}
2165
2166	/* Otherwise this is the case where the input is in a format currently
2167	* supported by the rest of the libpng write code; call it directly.
2168	*/
2169	else
2170	{
2171	png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2172	ptrdiff_t row_bytes = display->row_bytes;
2173	png_uint_32 y = image->height;
2174
2175	for (; y > 0; --y)
2176	{
2177	png_write_row(png_ptr, row);
2178	row += row_bytes;
2179	}
2180	}
2181
2182	png_write_end(png_ptr, info_ptr);
2183	return 1;
2184	}
2185
2186
2187	static void (PNGCBAPI
2188	image_memory_write)(png_structp png_ptr, png_bytep/const/ data, size_t size)
2189	{
2190	png_image_write_control display = png_voidcast(png_image_write_control,
2191	png_ptr->io_ptr/backdoor: png_get_io_ptr(png_ptr)/);
2192	png_alloc_size_t ob = display->output_bytes;
2193
2194	/* Check for overflow; this should never happen: */
2195	if (size <= ((png_alloc_size_t)-1) - ob)
2196	{
2197	/* I don't think libpng ever does this, but just in case: */
2198	if (size > 0)
2199	{
2200	if (display->memory_bytes >= ob+size) /* writing */
2201	memcpy(display->memory+ob, data, size);
2202
2203	/* Always update the size: */
2204	display->output_bytes = ob+size;
2205	}
2206	}
2207
2208	else
2209	png_error(png_ptr, "png_image_write_to_memory: PNG too big");
2210	}
2211
2212	static void (PNGCBAPI
2213	image_memory_flush)(png_structp png_ptr)
2214	{
2215	PNG_UNUSED(png_ptr)
2216	}
2217
2218	static int
2219	png_image_write_memory(png_voidp argument)
2220	{
2221	png_image_write_control display = png_voidcast(png_image_write_control,
2222	argument);
2223
2224	/* The rest of the memory-specific init and write_main in an error protected
2225	* environment. This case needs to use callbacks for the write operations
2226	* since libpng has no built in support for writing to memory.
2227	*/
2228	png_set_write_fn(display->image->opaque->png_ptr, display/io_ptr/,
2229	image_memory_write, image_memory_flush);
2230
2231	return png_image_write_main(display);
2232	}
2233
2234	int PNGAPI
2235	png_image_write_to_memory(png_imagep image, void *memory,
2236	png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
2237	const void buffer, png_int_32 row_stride, const void colormap)
2238	{
2239	/* Write the image to the given buffer, or count the bytes if it is NULL */
2240	if (image != NULL && image->version == PNG_IMAGE_VERSION)
2241	{
2242	if (memory_bytes != NULL && buffer != NULL)
2243	{
2244	/* This is to give the caller an easier error detection in the NULL
2245	* case and guard against uninitialized variable problems:
2246	*/
2247	if (memory == NULL)
2248	*memory_bytes = 0;
2249
2250	if (png_image_write_init(image) != 0)
2251	{
2252	png_image_write_control display;
2253	int result;
2254
2255	memset(&display, 0, (sizeof display));
2256	display.image = image;
2257	display.buffer = buffer;
2258	display.row_stride = row_stride;
2259	display.colormap = colormap;
2260	display.convert_to_8bit = convert_to_8bit;
2261	display.memory = png_voidcast(png_bytep, memory);
2262	display.memory_bytes = *memory_bytes;
2263	display.output_bytes = 0;
2264
2265	result = png_safe_execute(image, png_image_write_memory, &display);
2266	png_image_free(image);
2267
2268	/* write_memory returns true even if we ran out of buffer. */
2269	if (result)
2270	{
2271	/* On out-of-buffer this function returns '0' but still updates
2272	* memory_bytes:
2273	*/
2274	if (memory != NULL && display.output_bytes > *memory_bytes)
2275	result = 0;
2276
2277	*memory_bytes = display.output_bytes;
2278	}
2279
2280	return result;
2281	}
2282
2283	else
2284	return 0;
2285	}
2286
2287	else
2288	return png_image_error(image,
2289	"png_image_write_to_memory: invalid argument");
2290	}
2291
2292	else if (image != NULL)
2293	return png_image_error(image,
2294	"png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2295
2296	else
2297	return 0;
2298	}
2299
2300	#ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2301	int PNGAPI
2302	png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2303	const void buffer, png_int_32 row_stride, const void colormap)
2304	{
2305	/* Write the image to the given (FILE). /
2306	if (image != NULL && image->version == PNG_IMAGE_VERSION)
2307	{
2308	if (file != NULL && buffer != NULL)
2309	{
2310	if (png_image_write_init(image) != 0)
2311	{
2312	png_image_write_control display;
2313	int result;
2314
2315	/* This is slightly evil, but png_init_io doesn't do anything other
2316	* than this and we haven't changed the standard IO functions so
2317	* this saves a 'safe' function.
2318	*/
2319	image->opaque->png_ptr->io_ptr = file;
2320
2321	memset(&display, 0, (sizeof display));
2322	display.image = image;
2323	display.buffer = buffer;
2324	display.row_stride = row_stride;
2325	display.colormap = colormap;
2326	display.convert_to_8bit = convert_to_8bit;
2327
2328	result = png_safe_execute(image, png_image_write_main, &display);
2329	png_image_free(image);
2330	return result;
2331	}
2332
2333	else
2334	return 0;
2335	}
2336
2337	else
2338	return png_image_error(image,
2339	"png_image_write_to_stdio: invalid argument");
2340	}
2341
2342	else if (image != NULL)
2343	return png_image_error(image,
2344	"png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2345
2346	else
2347	return 0;
2348	}
2349
2350	int PNGAPI
2351	png_image_write_to_file(png_imagep image, const char *file_name,
2352	int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2353	const void *colormap)
2354	{
2355	/* Write the image to the named file. */
2356	if (image != NULL && image->version == PNG_IMAGE_VERSION)
2357	{
2358	if (file_name != NULL && buffer != NULL)
2359	{
2360	FILE *fp = fopen(file_name, "wb");
2361
2362	if (fp != NULL)
2363	{
2364	if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2365	row_stride, colormap) != 0)
2366	{
2367	int error; /* from fflush/fclose */
2368
2369	/* Make sure the file is flushed correctly. */
2370	if (fflush(fp) == 0 && ferror(fp) == 0)
2371	{
2372	if (fclose(fp) == 0)
2373	return 1;
2374
2375	error = errno; /* from fclose */
2376	}
2377
2378	else
2379	{
2380	error = errno; /* from fflush or ferror */
2381	(void)fclose(fp);
2382	}
2383
2384	(void)remove(file_name);
2385	/* The image has already been cleaned up; this is just used to
2386	* set the error (because the original write succeeded).
2387	*/
2388	return png_image_error(image, strerror(error));
2389	}
2390
2391	else
2392	{
2393	/* Clean up: just the opened file. */
2394	(void)fclose(fp);
2395	(void)remove(file_name);
2396	return 0;
2397	}
2398	}
2399
2400	else
2401	return png_image_error(image, strerror(errno));
2402	}
2403
2404	else
2405	return png_image_error(image,
2406	"png_image_write_to_file: invalid argument");
2407	}
2408
2409	else if (image != NULL)
2410	return png_image_error(image,
2411	"png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2412
2413	else
2414	return 0;
2415	}
2416	#endif /* SIMPLIFIED_WRITE_STDIO */
2417	#endif /* SIMPLIFIED_WRITE */
2418	#endif /* WRITE */

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source: vbox/trunk/src/libs/libpng-1.6.42/pngwrite.c@ 104389

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