pngwrite.c@ 102792

Last change on this file since 102792 was 96425, checked in by vboxsync, 2 years ago
src/libs: Switch to libpng-1.6.37, bugref:8515 [re-export]
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File size: 74.6 KB

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

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source: vbox/trunk/src/libs/libpng-1.6.37/pngwrite.c@ 102792

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