1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngwrite.c - general routines to write a PNG file
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Last changed in libpng 1.6.19 [November 12, 2015]
33 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 */
41
42 #include "pngpriv.h"
43 #if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
44 # include <errno.h>
45 #endif
46
47 #ifdef PNG_WRITE_SUPPORTED
48
49 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
50 /* Write out all the unknown chunks for the current given location */
51 static void
52 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
53 unsigned int where)
54 {
55 if (info_ptr->unknown_chunks_num != 0)
56 {
57 png_const_unknown_chunkp up;
58
59 png_debug(5, "writing extra chunks");
60
61 for (up = info_ptr->unknown_chunks;
62 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
63 ++up)
64 if ((up->location & where) != 0)
65 {
66 /* If per-chunk unknown chunk handling is enabled use it, otherwise
67 * just write the chunks the application has set.
68 */
69 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
70 int keep = png_handle_as_unknown(png_ptr, up->name);
71
72 /* NOTE: this code is radically different from the read side in the
73 * matter of handling an ancillary unknown chunk. In the read side
74 * the default behavior is to discard it, in the code below the default
75 * behavior is to write it. Critical chunks are, however, only
76 * written if explicitly listed or if the default is set to write all
77 * unknown chunks.
78 *
79 * The default handling is also slightly weird - it is not possible to
80 * stop the writing of all unsafe-to-copy chunks!
81 *
82 * TODO: REVIEW: this would seem to be a bug.
83 */
84 if (keep != PNG_HANDLE_CHUNK_NEVER &&
85 ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
86 keep == PNG_HANDLE_CHUNK_ALWAYS ||
87 (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
88 png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
89 #endif
90 {
91 /* TODO: review, what is wrong with a zero length unknown chunk? */
92 if (up->size == 0)
93 png_warning(png_ptr, "Writing zero-length unknown chunk");
94
95 png_write_chunk(png_ptr, up->name, up->data, up->size);
96 }
97 }
98 }
99 }
100 #endif /* WRITE_UNKNOWN_CHUNKS */
101
102 /* Writes all the PNG information. This is the suggested way to use the
103 * library. If you have a new chunk to add, make a function to write it,
104 * and put it in the correct location here. If you want the chunk written
105 * after the image data, put it in png_write_end(). I strongly encourage
106 * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
107 * the chunk, as that will keep the code from breaking if you want to just
108 * write a plain PNG file. If you have long comments, I suggest writing
109 * them in png_write_end(), and compressing them.
110 */
111 void PNGAPI
112 png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
113 {
114 png_debug(1, "in png_write_info_before_PLTE");
115
116 if (png_ptr == NULL || info_ptr == NULL)
117 return;
118
119 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
120 {
121 /* Write PNG signature */
122 png_write_sig(png_ptr);
123
124 #ifdef PNG_MNG_FEATURES_SUPPORTED
125 if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
126 png_ptr->mng_features_permitted != 0)
127 {
128 png_warning(png_ptr,
129 "MNG features are not allowed in a PNG datastream");
130 png_ptr->mng_features_permitted = 0;
131 }
132 #endif
133
134 /* Write IHDR information. */
135 png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
136 info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
137 info_ptr->filter_type,
138 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
139 info_ptr->interlace_type
140 #else
141 0
142 #endif
143 );
144
145 /* The rest of these check to see if the valid field has the appropriate
146 * flag set, and if it does, writes the chunk.
147 *
148 * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
149 * the chunks will be written if the WRITE routine is there and
150 * information * is available in the COLORSPACE. (See
151 * png_colorspace_sync_info in png.c for where the valid flags get set.)
152 *
153 * Under certain circumstances the colorspace can be invalidated without
154 * syncing the info_struct 'valid' flags; this happens if libpng detects
155 * an error and calls png_error while the color space is being set, yet
156 * the application continues writing the PNG. So check the 'invalid'
157 * flag here too.
158 */
159 #ifdef PNG_GAMMA_SUPPORTED
160 # ifdef PNG_WRITE_gAMA_SUPPORTED
161 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
162 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
163 (info_ptr->valid & PNG_INFO_gAMA) != 0)
164 png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
165 # endif
166 #endif
167
168 #ifdef PNG_COLORSPACE_SUPPORTED
169 /* Write only one of sRGB or an ICC profile. If a profile was supplied
170 * and it matches one of the known sRGB ones issue a warning.
171 */
172 # ifdef PNG_WRITE_iCCP_SUPPORTED
173 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
174 (info_ptr->valid & PNG_INFO_iCCP) != 0)
175 {
176 # ifdef PNG_WRITE_sRGB_SUPPORTED
177 if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
178 png_app_warning(png_ptr,
179 "profile matches sRGB but writing iCCP instead");
180 # endif
181
182 png_write_iCCP(png_ptr, info_ptr->iccp_name,
183 info_ptr->iccp_profile);
184 }
185 # ifdef PNG_WRITE_sRGB_SUPPORTED
186 else
187 # endif
188 # endif
189
190 # ifdef PNG_WRITE_sRGB_SUPPORTED
191 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
192 (info_ptr->valid & PNG_INFO_sRGB) != 0)
193 png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
194 # endif /* WRITE_sRGB */
195 #endif /* COLORSPACE */
196
197 #ifdef PNG_WRITE_sBIT_SUPPORTED
198 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
199 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
200 #endif
201
202 #ifdef PNG_COLORSPACE_SUPPORTED
203 # ifdef PNG_WRITE_cHRM_SUPPORTED
204 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
205 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
206 (info_ptr->valid & PNG_INFO_cHRM) != 0)
207 png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
208 # endif
209 #endif
210
211 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
212 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
213 #endif
214
215 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
216 }
217 }
218
219 void PNGAPI
220 png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
221 {
222 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
223 int i;
224 #endif
225
226 png_debug(1, "in png_write_info");
227
228 if (png_ptr == NULL || info_ptr == NULL)
229 return;
230
231 png_write_info_before_PLTE(png_ptr, info_ptr);
232
233 if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
234 png_write_PLTE(png_ptr, info_ptr->palette,
235 (png_uint_32)info_ptr->num_palette);
236
237 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
238 png_error(png_ptr, "Valid palette required for paletted images");
239
240 #ifdef PNG_WRITE_tRNS_SUPPORTED
241 if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
242 {
243 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
244 /* Invert the alpha channel (in tRNS) */
245 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
246 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
247 {
248 int j, jend;
249
250 jend = info_ptr->num_trans;
251 if (jend > PNG_MAX_PALETTE_LENGTH)
252 jend = PNG_MAX_PALETTE_LENGTH;
253
254 for (j = 0; j<jend; ++j)
255 info_ptr->trans_alpha[j] =
256 (png_byte)(255 - info_ptr->trans_alpha[j]);
257 }
258 #endif
259 png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
260 info_ptr->num_trans, info_ptr->color_type);
261 }
262 #endif
263 #ifdef PNG_WRITE_bKGD_SUPPORTED
264 if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
265 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
266 #endif
267
268 #ifdef PNG_WRITE_hIST_SUPPORTED
269 if ((info_ptr->valid & PNG_INFO_hIST) != 0)
270 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
271 #endif
272
273 #ifdef PNG_WRITE_oFFs_SUPPORTED
274 if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
275 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
276 info_ptr->offset_unit_type);
277 #endif
278
279 #ifdef PNG_WRITE_pCAL_SUPPORTED
280 if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
281 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
282 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
283 info_ptr->pcal_units, info_ptr->pcal_params);
284 #endif
285
286 #ifdef PNG_WRITE_sCAL_SUPPORTED
287 if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
288 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
289 info_ptr->scal_s_width, info_ptr->scal_s_height);
290 #endif /* sCAL */
291
292 #ifdef PNG_WRITE_pHYs_SUPPORTED
293 if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
294 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
295 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
296 #endif /* pHYs */
297
298 #ifdef PNG_WRITE_tIME_SUPPORTED
299 if ((info_ptr->valid & PNG_INFO_tIME) != 0)
300 {
301 png_write_tIME(png_ptr, &(info_ptr->mod_time));
302 png_ptr->mode |= PNG_WROTE_tIME;
303 }
304 #endif /* tIME */
305
306 #ifdef PNG_WRITE_sPLT_SUPPORTED
307 if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
308 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
309 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
310 #endif /* sPLT */
311
312 #ifdef PNG_WRITE_TEXT_SUPPORTED
313 /* Check to see if we need to write text chunks */
314 for (i = 0; i < info_ptr->num_text; i++)
315 {
316 png_debug2(2, "Writing header text chunk %d, type %d", i,
317 info_ptr->text[i].compression);
318 /* An internationalized chunk? */
319 if (info_ptr->text[i].compression > 0)
320 {
321 #ifdef PNG_WRITE_iTXt_SUPPORTED
322 /* Write international chunk */
323 png_write_iTXt(png_ptr,
324 info_ptr->text[i].compression,
325 info_ptr->text[i].key,
326 info_ptr->text[i].lang,
327 info_ptr->text[i].lang_key,
328 info_ptr->text[i].text);
329 /* Mark this chunk as written */
330 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
331 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
332 else
333 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
334 #else
335 png_warning(png_ptr, "Unable to write international text");
336 #endif
337 }
338
339 /* If we want a compressed text chunk */
340 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
341 {
342 #ifdef PNG_WRITE_zTXt_SUPPORTED
343 /* Write compressed chunk */
344 png_write_zTXt(png_ptr, info_ptr->text[i].key,
345 info_ptr->text[i].text, info_ptr->text[i].compression);
346 /* Mark this chunk as written */
347 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
348 #else
349 png_warning(png_ptr, "Unable to write compressed text");
350 #endif
351 }
352
353 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
354 {
355 #ifdef PNG_WRITE_tEXt_SUPPORTED
356 /* Write uncompressed chunk */
357 png_write_tEXt(png_ptr, info_ptr->text[i].key,
358 info_ptr->text[i].text,
359 0);
360 /* Mark this chunk as written */
361 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
362 #else
363 /* Can't get here */
364 png_warning(png_ptr, "Unable to write uncompressed text");
365 #endif
366 }
367 }
368 #endif /* tEXt */
369
370 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
371 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
372 #endif
373 }
374
375 /* Writes the end of the PNG file. If you don't want to write comments or
376 * time information, you can pass NULL for info. If you already wrote these
377 * in png_write_info(), do not write them again here. If you have long
378 * comments, I suggest writing them here, and compressing them.
379 */
380 void PNGAPI
381 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
382 {
383 png_debug(1, "in png_write_end");
384
385 if (png_ptr == NULL)
386 return;
387
388 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
389 png_error(png_ptr, "No IDATs written into file");
390
391 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
392 if (png_ptr->num_palette_max > png_ptr->num_palette)
393 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
394 #endif
395
396 /* See if user wants us to write information chunks */
397 if (info_ptr != NULL)
398 {
399 #ifdef PNG_WRITE_TEXT_SUPPORTED
400 int i; /* local index variable */
401 #endif
402 #ifdef PNG_WRITE_tIME_SUPPORTED
403 /* Check to see if user has supplied a time chunk */
404 if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
405 (png_ptr->mode & PNG_WROTE_tIME) == 0)
406 png_write_tIME(png_ptr, &(info_ptr->mod_time));
407
408 #endif
409 #ifdef PNG_WRITE_TEXT_SUPPORTED
410 /* Loop through comment chunks */
411 for (i = 0; i < info_ptr->num_text; i++)
412 {
413 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
414 info_ptr->text[i].compression);
415 /* An internationalized chunk? */
416 if (info_ptr->text[i].compression > 0)
417 {
418 #ifdef PNG_WRITE_iTXt_SUPPORTED
419 /* Write international chunk */
420 png_write_iTXt(png_ptr,
421 info_ptr->text[i].compression,
422 info_ptr->text[i].key,
423 info_ptr->text[i].lang,
424 info_ptr->text[i].lang_key,
425 info_ptr->text[i].text);
426 /* Mark this chunk as written */
427 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
428 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
429 else
430 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
431 #else
432 png_warning(png_ptr, "Unable to write international text");
433 #endif
434 }
435
436 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
437 {
438 #ifdef PNG_WRITE_zTXt_SUPPORTED
439 /* Write compressed chunk */
440 png_write_zTXt(png_ptr, info_ptr->text[i].key,
441 info_ptr->text[i].text, info_ptr->text[i].compression);
442 /* Mark this chunk as written */
443 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
444 #else
445 png_warning(png_ptr, "Unable to write compressed text");
446 #endif
447 }
448
449 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
450 {
451 #ifdef PNG_WRITE_tEXt_SUPPORTED
452 /* Write uncompressed chunk */
453 png_write_tEXt(png_ptr, info_ptr->text[i].key,
454 info_ptr->text[i].text, 0);
455 /* Mark this chunk as written */
456 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
457 #else
458 png_warning(png_ptr, "Unable to write uncompressed text");
459 #endif
460 }
461 }
462 #endif
463 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
464 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
465 #endif
466 }
467
468 png_ptr->mode |= PNG_AFTER_IDAT;
469
470 /* Write end of PNG file */
471 png_write_IEND(png_ptr);
472
473 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
474 * and restored again in libpng-1.2.30, may cause some applications that
475 * do not set png_ptr->output_flush_fn to crash. If your application
476 * experiences a problem, please try building libpng with
477 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
478 * png-mng-implement at lists.sf.net .
479 */
480 #ifdef PNG_WRITE_FLUSH_SUPPORTED
481 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
482 png_flush(png_ptr);
483 # endif
484 #endif
485 }
486
487 #ifdef PNG_CONVERT_tIME_SUPPORTED
488 void PNGAPI
489 png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)
490 {
491 png_debug(1, "in png_convert_from_struct_tm");
492
493 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
494 ptime->month = (png_byte)(ttime->tm_mon + 1);
495 ptime->day = (png_byte)ttime->tm_mday;
496 ptime->hour = (png_byte)ttime->tm_hour;
497 ptime->minute = (png_byte)ttime->tm_min;
498 ptime->second = (png_byte)ttime->tm_sec;
499 }
500
501 void PNGAPI
502 png_convert_from_time_t(png_timep ptime, time_t ttime)
503 {
504 struct tm *tbuf;
505
506 png_debug(1, "in png_convert_from_time_t");
507
508 tbuf = gmtime(&ttime);
509 png_convert_from_struct_tm(ptime, tbuf);
510 }
511 #endif
512
513 /* Initialize png_ptr structure, and allocate any memory needed */
514 PNG_FUNCTION(png_structp,PNGAPI
515 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
516 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
517 {
518 #ifndef PNG_USER_MEM_SUPPORTED
519 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
520 error_fn, warn_fn, NULL, NULL, NULL);
521 #else
522 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
523 warn_fn, NULL, NULL, NULL);
524 }
525
526 /* Alternate initialize png_ptr structure, and allocate any memory needed */
527 PNG_FUNCTION(png_structp,PNGAPI
528 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
529 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
530 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
531 {
532 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
533 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
534 #endif /* USER_MEM */
535 if (png_ptr != NULL)
536 {
537 /* Set the zlib control values to defaults; they can be overridden by the
538 * application after the struct has been created.
539 */
540 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
541
542 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
543 * pngwutil.c defaults it according to whether or not filters will be
544 * used, and ignores this setting.
545 */
546 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
547 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
548 png_ptr->zlib_mem_level = 8;
549 png_ptr->zlib_window_bits = 15;
550 png_ptr->zlib_method = 8;
551
552 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
553 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
554 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
555 png_ptr->zlib_text_mem_level = 8;
556 png_ptr->zlib_text_window_bits = 15;
557 png_ptr->zlib_text_method = 8;
558 #endif /* WRITE_COMPRESSED_TEXT */
559
560 /* This is a highly dubious configuration option; by default it is off,
561 * but it may be appropriate for private builds that are testing
562 * extensions not conformant to the current specification, or of
563 * applications that must not fail to write at all costs!
564 */
565 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
566 /* In stable builds only warn if an application error can be completely
567 * handled.
568 */
569 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
570 #endif
571
572 /* App warnings are warnings in release (or release candidate) builds but
573 * are errors during development.
574 */
575 #if PNG_RELEASE_BUILD
576 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
577 #endif
578
579 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
580 * do it itself) avoiding setting the default function if it is not
581 * required.
582 */
583 png_set_write_fn(png_ptr, NULL, NULL, NULL);
584 }
585
586 return png_ptr;
587 }
588
589
590 /* Write a few rows of image data. If the image is interlaced,
591 * either you will have to write the 7 sub images, or, if you
592 * have called png_set_interlace_handling(), you will have to
593 * "write" the image seven times.
594 */
595 void PNGAPI
596 png_write_rows(png_structrp png_ptr, png_bytepp row,
597 png_uint_32 num_rows)
598 {
599 png_uint_32 i; /* row counter */
600 png_bytepp rp; /* row pointer */
601
602 png_debug(1, "in png_write_rows");
603
604 if (png_ptr == NULL)
605 return;
606
607 /* Loop through the rows */
608 for (i = 0, rp = row; i < num_rows; i++, rp++)
609 {
610 png_write_row(png_ptr, *rp);
611 }
612 }
613
614 /* Write the image. You only need to call this function once, even
615 * if you are writing an interlaced image.
616 */
617 void PNGAPI
618 png_write_image(png_structrp png_ptr, png_bytepp image)
619 {
620 png_uint_32 i; /* row index */
621 int pass, num_pass; /* pass variables */
622 png_bytepp rp; /* points to current row */
623
624 if (png_ptr == NULL)
625 return;
626
627 png_debug(1, "in png_write_image");
628
629 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
630 /* Initialize interlace handling. If image is not interlaced,
631 * this will set pass to 1
632 */
633 num_pass = png_set_interlace_handling(png_ptr);
634 #else
635 num_pass = 1;
636 #endif
637 /* Loop through passes */
638 for (pass = 0; pass < num_pass; pass++)
639 {
640 /* Loop through image */
641 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
642 {
643 png_write_row(png_ptr, *rp);
644 }
645 }
646 }
647
648 #ifdef PNG_MNG_FEATURES_SUPPORTED
649 /* Performs intrapixel differencing */
650 static void
651 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
652 {
653 png_debug(1, "in png_do_write_intrapixel");
654
655 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
656 {
657 int bytes_per_pixel;
658 png_uint_32 row_width = row_info->width;
659 if (row_info->bit_depth == 8)
660 {
661 png_bytep rp;
662 png_uint_32 i;
663
664 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
665 bytes_per_pixel = 3;
666
667 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
668 bytes_per_pixel = 4;
669
670 else
671 return;
672
673 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
674 {
675 *(rp) = (png_byte)(*rp - *(rp + 1));
676 *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
677 }
678 }
679
680 #ifdef PNG_WRITE_16BIT_SUPPORTED
681 else if (row_info->bit_depth == 16)
682 {
683 png_bytep rp;
684 png_uint_32 i;
685
686 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
687 bytes_per_pixel = 6;
688
689 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
690 bytes_per_pixel = 8;
691
692 else
693 return;
694
695 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
696 {
697 png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
698 png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
699 png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
700 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
701 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
702 *(rp ) = (png_byte)(red >> 8);
703 *(rp + 1) = (png_byte)red;
704 *(rp + 4) = (png_byte)(blue >> 8);
705 *(rp + 5) = (png_byte)blue;
706 }
707 }
708 #endif /* WRITE_16BIT */
709 }
710 }
711 #endif /* MNG_FEATURES */
712
713 /* Called by user to write a row of image data */
714 void PNGAPI
715 png_write_row(png_structrp png_ptr, png_const_bytep row)
716 {
717 /* 1.5.6: moved from png_struct to be a local structure: */
718 png_row_info row_info;
719
720 if (png_ptr == NULL)
721 return;
722
723 png_debug2(1, "in png_write_row (row %u, pass %d)",
724 png_ptr->row_number, png_ptr->pass);
725
726 /* Initialize transformations and other stuff if first time */
727 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
728 {
729 /* Make sure we wrote the header info */
730 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
731 png_error(png_ptr,
732 "png_write_info was never called before png_write_row");
733
734 /* Check for transforms that have been set but were defined out */
735 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
736 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
737 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
738 #endif
739
740 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
741 if ((png_ptr->transformations & PNG_FILLER) != 0)
742 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
743 #endif
744 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
745 defined(PNG_READ_PACKSWAP_SUPPORTED)
746 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
747 png_warning(png_ptr,
748 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
749 #endif
750
751 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
752 if ((png_ptr->transformations & PNG_PACK) != 0)
753 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
754 #endif
755
756 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
757 if ((png_ptr->transformations & PNG_SHIFT) != 0)
758 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
759 #endif
760
761 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
762 if ((png_ptr->transformations & PNG_BGR) != 0)
763 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
764 #endif
765
766 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
767 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
768 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
769 #endif
770
771 png_write_start_row(png_ptr);
772 }
773
774 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
775 /* If interlaced and not interested in row, return */
776 if (png_ptr->interlaced != 0 &&
777 (png_ptr->transformations & PNG_INTERLACE) != 0)
778 {
779 switch (png_ptr->pass)
780 {
781 case 0:
782 if ((png_ptr->row_number & 0x07) != 0)
783 {
784 png_write_finish_row(png_ptr);
785 return;
786 }
787 break;
788
789 case 1:
790 if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
791 {
792 png_write_finish_row(png_ptr);
793 return;
794 }
795 break;
796
797 case 2:
798 if ((png_ptr->row_number & 0x07) != 4)
799 {
800 png_write_finish_row(png_ptr);
801 return;
802 }
803 break;
804
805 case 3:
806 if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
807 {
808 png_write_finish_row(png_ptr);
809 return;
810 }
811 break;
812
813 case 4:
814 if ((png_ptr->row_number & 0x03) != 2)
815 {
816 png_write_finish_row(png_ptr);
817 return;
818 }
819 break;
820
821 case 5:
822 if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
823 {
824 png_write_finish_row(png_ptr);
825 return;
826 }
827 break;
828
829 case 6:
830 if ((png_ptr->row_number & 0x01) == 0)
831 {
832 png_write_finish_row(png_ptr);
833 return;
834 }
835 break;
836
837 default: /* error: ignore it */
838 break;
839 }
840 }
841 #endif
842
843 /* Set up row info for transformations */
844 row_info.color_type = png_ptr->color_type;
845 row_info.width = png_ptr->usr_width;
846 row_info.channels = png_ptr->usr_channels;
847 row_info.bit_depth = png_ptr->usr_bit_depth;
848 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
849 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
850
851 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
852 png_debug1(3, "row_info->width = %u", row_info.width);
853 png_debug1(3, "row_info->channels = %d", row_info.channels);
854 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
855 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
856 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
857
858 /* Copy user's row into buffer, leaving room for filter byte. */
859 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
860
861 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
862 /* Handle interlacing */
863 if (png_ptr->interlaced && png_ptr->pass < 6 &&
864 (png_ptr->transformations & PNG_INTERLACE) != 0)
865 {
866 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
867 /* This should always get caught above, but still ... */
868 if (row_info.width == 0)
869 {
870 png_write_finish_row(png_ptr);
871 return;
872 }
873 }
874 #endif
875
876 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
877 /* Handle other transformations */
878 if (png_ptr->transformations != 0)
879 png_do_write_transformations(png_ptr, &row_info);
880 #endif
881
882 /* At this point the row_info pixel depth must match the 'transformed' depth,
883 * which is also the output depth.
884 */
885 if (row_info.pixel_depth != png_ptr->pixel_depth ||
886 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
887 png_error(png_ptr, "internal write transform logic error");
888
889 #ifdef PNG_MNG_FEATURES_SUPPORTED
890 /* Write filter_method 64 (intrapixel differencing) only if
891 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
892 * 2. Libpng did not write a PNG signature (this filter_method is only
893 * used in PNG datastreams that are embedded in MNG datastreams) and
894 * 3. The application called png_permit_mng_features with a mask that
895 * included PNG_FLAG_MNG_FILTER_64 and
896 * 4. The filter_method is 64 and
897 * 5. The color_type is RGB or RGBA
898 */
899 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
900 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
901 {
902 /* Intrapixel differencing */
903 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
904 }
905 #endif
906
907 /* Added at libpng-1.5.10 */
908 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
909 /* Check for out-of-range palette index */
910 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
911 png_ptr->num_palette_max >= 0)
912 png_do_check_palette_indexes(png_ptr, &row_info);
913 #endif
914
915 /* Find a filter if necessary, filter the row and write it out. */
916 png_write_find_filter(png_ptr, &row_info);
917
918 if (png_ptr->write_row_fn != NULL)
919 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
920 }
921
922 #ifdef PNG_WRITE_FLUSH_SUPPORTED
923 /* Set the automatic flush interval or 0 to turn flushing off */
924 void PNGAPI
925 png_set_flush(png_structrp png_ptr, int nrows)
926 {
927 png_debug(1, "in png_set_flush");
928
929 if (png_ptr == NULL)
930 return;
931
932 png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
933 }
934
935 /* Flush the current output buffers now */
936 void PNGAPI
937 png_write_flush(png_structrp png_ptr)
938 {
939 png_debug(1, "in png_write_flush");
940
941 if (png_ptr == NULL)
942 return;
943
944 /* We have already written out all of the data */
945 if (png_ptr->row_number >= png_ptr->num_rows)
946 return;
947
948 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
949 png_ptr->flush_rows = 0;
950 png_flush(png_ptr);
951 }
952 #endif /* WRITE_FLUSH */
953
954 /* Free any memory used in png_ptr struct without freeing the struct itself. */
955 static void
956 png_write_destroy(png_structrp png_ptr)
957 {
958 png_debug(1, "in png_write_destroy");
959
960 /* Free any memory zlib uses */
961 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
962 deflateEnd(&png_ptr->zstream);
963
964 /* Free our memory. png_free checks NULL for us. */
965 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
966 png_free(png_ptr, png_ptr->row_buf);
967 png_ptr->row_buf = NULL;
968 #ifdef PNG_WRITE_FILTER_SUPPORTED
969 png_free(png_ptr, png_ptr->prev_row);
970 png_free(png_ptr, png_ptr->try_row);
971 png_free(png_ptr, png_ptr->tst_row);
972 png_ptr->prev_row = NULL;
973 png_ptr->try_row = NULL;
974 png_ptr->tst_row = NULL;
975 #endif
976
977 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
978 png_free(png_ptr, png_ptr->chunk_list);
979 png_ptr->chunk_list = NULL;
980 #endif
981
982 /* The error handling and memory handling information is left intact at this
983 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
984 * for how this happens.
985 */
986 }
987
988 /* Free all memory used by the write.
989 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
990 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
991 * the passed in info_structs but it would quietly fail to free any of the data
992 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
993 * has no png_ptr.)
994 */
995 void PNGAPI
996 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
997 {
998 png_debug(1, "in png_destroy_write_struct");
999
1000 if (png_ptr_ptr != NULL)
1001 {
1002 png_structrp png_ptr = *png_ptr_ptr;
1003
1004 if (png_ptr != NULL) /* added in libpng 1.6.0 */
1005 {
1006 png_destroy_info_struct(png_ptr, info_ptr_ptr);
1007
1008 *png_ptr_ptr = NULL;
1009 png_write_destroy(png_ptr);
1010 png_destroy_png_struct(png_ptr);
1011 }
1012 }
1013 }
1014
1015 /* Allow the application to select one or more row filters to use. */
1016 void PNGAPI
1017 png_set_filter(png_structrp png_ptr, int method, int filters)
1018 {
1019 png_debug(1, "in png_set_filter");
1020
1021 if (png_ptr == NULL)
1022 return;
1023
1024 #ifdef PNG_MNG_FEATURES_SUPPORTED
1025 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
1026 (method == PNG_INTRAPIXEL_DIFFERENCING))
1027 method = PNG_FILTER_TYPE_BASE;
1028
1029 #endif
1030 if (method == PNG_FILTER_TYPE_BASE)
1031 {
1032 switch (filters & (PNG_ALL_FILTERS | 0x07))
1033 {
1034 #ifdef PNG_WRITE_FILTER_SUPPORTED
1035 case 5:
1036 case 6:
1037 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1038 /* FALL THROUGH */
1039 #endif /* WRITE_FILTER */
1040 case PNG_FILTER_VALUE_NONE:
1041 png_ptr->do_filter = PNG_FILTER_NONE; break;
1042
1043 #ifdef PNG_WRITE_FILTER_SUPPORTED
1044 case PNG_FILTER_VALUE_SUB:
1045 png_ptr->do_filter = PNG_FILTER_SUB; break;
1046
1047 case PNG_FILTER_VALUE_UP:
1048 png_ptr->do_filter = PNG_FILTER_UP; break;
1049
1050 case PNG_FILTER_VALUE_AVG:
1051 png_ptr->do_filter = PNG_FILTER_AVG; break;
1052
1053 case PNG_FILTER_VALUE_PAETH:
1054 png_ptr->do_filter = PNG_FILTER_PAETH; break;
1055
1056 default:
1057 png_ptr->do_filter = (png_byte)filters; break;
1058 #else
1059 default:
1060 png_app_error(png_ptr, "Unknown row filter for method 0");
1061 #endif /* WRITE_FILTER */
1062 }
1063
1064 #ifdef PNG_WRITE_FILTER_SUPPORTED
1065 /* If we have allocated the row_buf, this means we have already started
1066 * with the image and we should have allocated all of the filter buffers
1067 * that have been selected. If prev_row isn't already allocated, then
1068 * it is too late to start using the filters that need it, since we
1069 * will be missing the data in the previous row. If an application
1070 * wants to start and stop using particular filters during compression,
1071 * it should start out with all of the filters, and then remove them
1072 * or add them back after the start of compression.
1073 *
1074 * NOTE: this is a nasty constraint on the code, because it means that the
1075 * prev_row buffer must be maintained even if there are currently no
1076 * 'prev_row' requiring filters active.
1077 */
1078 if (png_ptr->row_buf != NULL)
1079 {
1080 int num_filters;
1081 png_alloc_size_t buf_size;
1082
1083 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1084 * images cannot benefit from certain filters. If this isn't done here
1085 * the check below will fire on 1 pixel high images.
1086 */
1087 if (png_ptr->height == 1)
1088 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1089
1090 if (png_ptr->width == 1)
1091 filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1092
1093 if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
1094 && png_ptr->prev_row == NULL)
1095 {
1096 /* This is the error case, however it is benign - the previous row
1097 * is not available so the filter can't be used. Just warn here.
1098 */
1099 png_app_warning(png_ptr,
1100 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1101 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1102 }
1103
1104 num_filters = 0;
1105
1106 if (filters & PNG_FILTER_SUB)
1107 num_filters++;
1108
1109 if (filters & PNG_FILTER_UP)
1110 num_filters++;
1111
1112 if (filters & PNG_FILTER_AVG)
1113 num_filters++;
1114
1115 if (filters & PNG_FILTER_PAETH)
1116 num_filters++;
1117
1118 /* Allocate needed row buffers if they have not already been
1119 * allocated.
1120 */
1121 buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1122 png_ptr->width) + 1;
1123
1124 if (png_ptr->try_row == NULL)
1125 png_ptr->try_row = png_voidcast(png_bytep,
1126 png_malloc(png_ptr, buf_size));
1127
1128 if (num_filters > 1)
1129 {
1130 if (png_ptr->tst_row == NULL)
1131 png_ptr->tst_row = png_voidcast(png_bytep,
1132 png_malloc(png_ptr, buf_size));
1133 }
1134 }
1135 png_ptr->do_filter = (png_byte)filters;
1136 #endif
1137 }
1138 else
1139 png_error(png_ptr, "Unknown custom filter method");
1140 }
1141
1142 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1143 /* Provide floating and fixed point APIs */
1144 #ifdef PNG_FLOATING_POINT_SUPPORTED
1145 void PNGAPI
1146 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1147 int num_weights, png_const_doublep filter_weights,
1148 png_const_doublep filter_costs)
1149 {
1150 PNG_UNUSED(png_ptr)
1151 PNG_UNUSED(heuristic_method)
1152 PNG_UNUSED(num_weights)
1153 PNG_UNUSED(filter_weights)
1154 PNG_UNUSED(filter_costs)
1155 }
1156 #endif /* FLOATING_POINT */
1157
1158 #ifdef PNG_FIXED_POINT_SUPPORTED
1159 void PNGAPI
1160 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1161 int num_weights, png_const_fixed_point_p filter_weights,
1162 png_const_fixed_point_p filter_costs)
1163 {
1164 PNG_UNUSED(png_ptr)
1165 PNG_UNUSED(heuristic_method)
1166 PNG_UNUSED(num_weights)
1167 PNG_UNUSED(filter_weights)
1168 PNG_UNUSED(filter_costs)
1169 }
1170 #endif /* FIXED_POINT */
1171 #endif /* WRITE_WEIGHTED_FILTER */
1172
1173 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1174 void PNGAPI
1175 png_set_compression_level(png_structrp png_ptr, int level)
1176 {
1177 png_debug(1, "in png_set_compression_level");
1178
1179 if (png_ptr == NULL)
1180 return;
1181
1182 png_ptr->zlib_level = level;
1183 }
1184
1185 void PNGAPI
1186 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1187 {
1188 png_debug(1, "in png_set_compression_mem_level");
1189
1190 if (png_ptr == NULL)
1191 return;
1192
1193 png_ptr->zlib_mem_level = mem_level;
1194 }
1195
1196 void PNGAPI
1197 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1198 {
1199 png_debug(1, "in png_set_compression_strategy");
1200
1201 if (png_ptr == NULL)
1202 return;
1203
1204 /* The flag setting here prevents the libpng dynamic selection of strategy.
1205 */
1206 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1207 png_ptr->zlib_strategy = strategy;
1208 }
1209
1210 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1211 * smaller value of window_bits if it can do so safely.
1212 */
1213 void PNGAPI
1214 png_set_compression_window_bits(png_structrp png_ptr, int 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 if (png_ptr == NULL)
1300 return;
1301
1302 if (window_bits > 15)
1303 {
1304 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1305 window_bits = 15;
1306 }
1307
1308 else if (window_bits < 8)
1309 {
1310 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1311 window_bits = 8;
1312 }
1313
1314 png_ptr->zlib_text_window_bits = window_bits;
1315 }
1316
1317 void PNGAPI
1318 png_set_text_compression_method(png_structrp png_ptr, int method)
1319 {
1320 png_debug(1, "in png_set_text_compression_method");
1321
1322 if (png_ptr == NULL)
1323 return;
1324
1325 if (method != 8)
1326 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1327
1328 png_ptr->zlib_text_method = method;
1329 }
1330 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1331 /* end of API added to libpng-1.5.4 */
1332
1333 void PNGAPI
1334 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1335 {
1336 if (png_ptr == NULL)
1337 return;
1338
1339 png_ptr->write_row_fn = write_row_fn;
1340 }
1341
1342 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1343 void PNGAPI
1344 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1345 write_user_transform_fn)
1346 {
1347 png_debug(1, "in png_set_write_user_transform_fn");
1348
1349 if (png_ptr == NULL)
1350 return;
1351
1352 png_ptr->transformations |= PNG_USER_TRANSFORM;
1353 png_ptr->write_user_transform_fn = write_user_transform_fn;
1354 }
1355 #endif
1356
1357
1358 #ifdef PNG_INFO_IMAGE_SUPPORTED
1359 void PNGAPI
1360 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1361 int transforms, voidp params)
1362 {
1363 if (png_ptr == NULL || info_ptr == NULL)
1364 return;
1365
1366 if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1367 {
1368 png_app_error(png_ptr, "no rows for png_write_image to write");
1369 return;
1370 }
1371
1372 /* Write the file header information. */
1373 png_write_info(png_ptr, info_ptr);
1374
1375 /* ------ these transformations don't touch the info structure ------- */
1376
1377 /* Invert monochrome pixels */
1378 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1379 #ifdef PNG_WRITE_INVERT_SUPPORTED
1380 png_set_invert_mono(png_ptr);
1381 #else
1382 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1383 #endif
1384
1385 /* Shift the pixels up to a legal bit depth and fill in
1386 * as appropriate to correctly scale the image.
1387 */
1388 if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1389 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1390 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1391 png_set_shift(png_ptr, &info_ptr->sig_bit);
1392 #else
1393 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1394 #endif
1395
1396 /* Pack pixels into bytes */
1397 if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1398 #ifdef PNG_WRITE_PACK_SUPPORTED
1399 png_set_packing(png_ptr);
1400 #else
1401 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1402 #endif
1403
1404 /* Swap location of alpha bytes from ARGB to RGBA */
1405 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1406 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1407 png_set_swap_alpha(png_ptr);
1408 #else
1409 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1410 #endif
1411
1412 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1413 * RGB, note that the code expects the input color type to be G or RGB; no
1414 * alpha channel.
1415 */
1416 if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
1417 PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1418 {
1419 #ifdef PNG_WRITE_FILLER_SUPPORTED
1420 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1421 {
1422 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1423 png_app_error(png_ptr,
1424 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1425
1426 /* Continue if ignored - this is the pre-1.6.10 behavior */
1427 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1428 }
1429
1430 else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1431 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1432 #else
1433 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1434 #endif
1435 }
1436
1437 /* Flip BGR pixels to RGB */
1438 if ((transforms & PNG_TRANSFORM_BGR) != 0)
1439 #ifdef PNG_WRITE_BGR_SUPPORTED
1440 png_set_bgr(png_ptr);
1441 #else
1442 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1443 #endif
1444
1445 /* Swap bytes of 16-bit files to most significant byte first */
1446 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1447 #ifdef PNG_WRITE_SWAP_SUPPORTED
1448 png_set_swap(png_ptr);
1449 #else
1450 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1451 #endif
1452
1453 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1454 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1455 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1456 png_set_packswap(png_ptr);
1457 #else
1458 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1459 #endif
1460
1461 /* Invert the alpha channel from opacity to transparency */
1462 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1463 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1464 png_set_invert_alpha(png_ptr);
1465 #else
1466 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1467 #endif
1468
1469 /* ----------------------- end of transformations ------------------- */
1470
1471 /* Write the bits */
1472 png_write_image(png_ptr, info_ptr->row_pointers);
1473
1474 /* It is REQUIRED to call this to finish writing the rest of the file */
1475 png_write_end(png_ptr, info_ptr);
1476
1477 PNG_UNUSED(params)
1478 }
1479 #endif
1480
1481
1482 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1483 # ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
1484 /* Initialize the write structure - general purpose utility. */
1485 static int
1486 png_image_write_init(png_imagep image)
1487 {
1488 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1489 png_safe_error, png_safe_warning);
1490
1491 if (png_ptr != NULL)
1492 {
1493 png_infop info_ptr = png_create_info_struct(png_ptr);
1494
1495 if (info_ptr != NULL)
1496 {
1497 png_controlp control = png_voidcast(png_controlp,
1498 png_malloc_warn(png_ptr, (sizeof *control)));
1499
1500 if (control != NULL)
1501 {
1502 memset(control, 0, (sizeof *control));
1503
1504 control->png_ptr = png_ptr;
1505 control->info_ptr = info_ptr;
1506 control->for_write = 1;
1507
1508 image->opaque = control;
1509 return 1;
1510 }
1511
1512 /* Error clean up */
1513 png_destroy_info_struct(png_ptr, &info_ptr);
1514 }
1515
1516 png_destroy_write_struct(&png_ptr, NULL);
1517 }
1518
1519 return png_image_error(image, "png_image_write_: out of memory");
1520 }
1521
1522 /* Arguments to png_image_write_main: */
1523 typedef struct
1524 {
1525 /* Arguments: */
1526 png_imagep image;
1527 png_const_voidp buffer;
1528 png_int_32 row_stride;
1529 png_const_voidp colormap;
1530 int convert_to_8bit;
1531 /* Local variables: */
1532 png_const_voidp first_row;
1533 ptrdiff_t row_bytes;
1534 png_voidp local_row;
1535 } png_image_write_control;
1536
1537 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1538 * do any necessary byte swapping. The component order is defined by the
1539 * png_image format value.
1540 */
1541 static int
1542 png_write_image_16bit(png_voidp argument)
1543 {
1544 png_image_write_control *display = png_voidcast(png_image_write_control*,
1545 argument);
1546 png_imagep image = display->image;
1547 png_structrp png_ptr = image->opaque->png_ptr;
1548
1549 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1550 display->first_row);
1551 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1552 png_uint_16p row_end;
1553 const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
1554 int aindex = 0;
1555 png_uint_32 y = image->height;
1556
1557 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1558 {
1559 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1560 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1561 {
1562 aindex = -1;
1563 ++input_row; /* To point to the first component */
1564 ++output_row;
1565 }
1566 else
1567 aindex = channels;
1568 # else
1569 aindex = channels;
1570 # endif
1571 }
1572
1573 else
1574 png_error(png_ptr, "png_write_image: internal call error");
1575
1576 /* Work out the output row end and count over this, note that the increment
1577 * above to 'row' means that row_end can actually be beyond the end of the
1578 * row; this is correct.
1579 */
1580 row_end = output_row + image->width * (channels+1);
1581
1582 while (y-- > 0)
1583 {
1584 png_const_uint_16p in_ptr = input_row;
1585 png_uint_16p out_ptr = output_row;
1586
1587 while (out_ptr < row_end)
1588 {
1589 const png_uint_16 alpha = in_ptr[aindex];
1590 png_uint_32 reciprocal = 0;
1591 int c;
1592
1593 out_ptr[aindex] = alpha;
1594
1595 /* Calculate a reciprocal. The correct calculation is simply
1596 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1597 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1598 * is only initialized when required.
1599 */
1600 if (alpha > 0 && alpha < 65535)
1601 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1602
1603 c = channels;
1604 do /* always at least one channel */
1605 {
1606 png_uint_16 component = *in_ptr++;
1607
1608 /* The following gives 65535 for an alpha of 0, which is fine,
1609 * otherwise if 0/0 is represented as some other value there is more
1610 * likely to be a discontinuity which will probably damage
1611 * compression when moving from a fully transparent area to a
1612 * nearly transparent one. (The assumption here is that opaque
1613 * areas tend not to be 0 intensity.)
1614 */
1615 if (component >= alpha)
1616 component = 65535;
1617
1618 /* component<alpha, so component/alpha is less than one and
1619 * component*reciprocal is less than 2^31.
1620 */
1621 else if (component > 0 && alpha < 65535)
1622 {
1623 png_uint_32 calc = component * reciprocal;
1624 calc += 16384; /* round to nearest */
1625 component = (png_uint_16)(calc >> 15);
1626 }
1627
1628 *out_ptr++ = component;
1629 }
1630 while (--c > 0);
1631
1632 /* Skip to next component (skip the intervening alpha channel) */
1633 ++in_ptr;
1634 ++out_ptr;
1635 }
1636
1637 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1638 input_row += display->row_bytes/(sizeof (png_uint_16));
1639 }
1640
1641 return 1;
1642 }
1643
1644 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1645 * is present it must be removed from the components, the components are then
1646 * written in sRGB encoding. No components are added or removed.
1647 *
1648 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1649 * calculation can be done to 15 bits of accuracy; however, the output needs to
1650 * be scaled in the range 0..255*65535, so include that scaling here.
1651 */
1652 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
1653
1654 static png_byte
1655 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1656 png_uint_32 reciprocal/*from the above macro*/)
1657 {
1658 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1659 * is represented as some other value there is more likely to be a
1660 * discontinuity which will probably damage compression when moving from a
1661 * fully transparent area to a nearly transparent one. (The assumption here
1662 * is that opaque areas tend not to be 0 intensity.)
1663 *
1664 * There is a rounding problem here; if alpha is less than 128 it will end up
1665 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1666 * output change for this too.
1667 */
1668 if (component >= alpha || alpha < 128)
1669 return 255;
1670
1671 /* component<alpha, so component/alpha is less than one and
1672 * component*reciprocal is less than 2^31.
1673 */
1674 else if (component > 0)
1675 {
1676 /* The test is that alpha/257 (rounded) is less than 255, the first value
1677 * that becomes 255 is 65407.
1678 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1679 * be exact!) [Could also test reciprocal != 0]
1680 */
1681 if (alpha < 65407)
1682 {
1683 component *= reciprocal;
1684 component += 64; /* round to nearest */
1685 component >>= 7;
1686 }
1687
1688 else
1689 component *= 255;
1690
1691 /* Convert the component to sRGB. */
1692 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1693 }
1694
1695 else
1696 return 0;
1697 }
1698
1699 static int
1700 png_write_image_8bit(png_voidp argument)
1701 {
1702 png_image_write_control *display = png_voidcast(png_image_write_control*,
1703 argument);
1704 png_imagep image = display->image;
1705 png_structrp png_ptr = image->opaque->png_ptr;
1706
1707 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1708 display->first_row);
1709 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1710 png_uint_32 y = image->height;
1711 const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
1712
1713 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1714 {
1715 png_bytep row_end;
1716 int aindex;
1717
1718 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1719 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1720 {
1721 aindex = -1;
1722 ++input_row; /* To point to the first component */
1723 ++output_row;
1724 }
1725
1726 else
1727 # endif
1728 aindex = channels;
1729
1730 /* Use row_end in place of a loop counter: */
1731 row_end = output_row + image->width * (channels+1);
1732
1733 while (y-- > 0)
1734 {
1735 png_const_uint_16p in_ptr = input_row;
1736 png_bytep out_ptr = output_row;
1737
1738 while (out_ptr < row_end)
1739 {
1740 png_uint_16 alpha = in_ptr[aindex];
1741 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1742 png_uint_32 reciprocal = 0;
1743 int c;
1744
1745 /* Scale and write the alpha channel. */
1746 out_ptr[aindex] = alphabyte;
1747
1748 if (alphabyte > 0 && alphabyte < 255)
1749 reciprocal = UNP_RECIPROCAL(alpha);
1750
1751 c = channels;
1752 do /* always at least one channel */
1753 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1754 while (--c > 0);
1755
1756 /* Skip to next component (skip the intervening alpha channel) */
1757 ++in_ptr;
1758 ++out_ptr;
1759 } /* while out_ptr < row_end */
1760
1761 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1762 display->local_row));
1763 input_row += display->row_bytes/(sizeof (png_uint_16));
1764 } /* while y */
1765 }
1766
1767 else
1768 {
1769 /* No alpha channel, so the row_end really is the end of the row and it
1770 * is sufficient to loop over the components one by one.
1771 */
1772 png_bytep row_end = output_row + image->width * channels;
1773
1774 while (y-- > 0)
1775 {
1776 png_const_uint_16p in_ptr = input_row;
1777 png_bytep out_ptr = output_row;
1778
1779 while (out_ptr < row_end)
1780 {
1781 png_uint_32 component = *in_ptr++;
1782
1783 component *= 255;
1784 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1785 }
1786
1787 png_write_row(png_ptr, output_row);
1788 input_row += display->row_bytes/(sizeof (png_uint_16));
1789 }
1790 }
1791
1792 return 1;
1793 }
1794
1795 static void
1796 png_image_set_PLTE(png_image_write_control *display)
1797 {
1798 const png_imagep image = display->image;
1799 const void *cmap = display->colormap;
1800 const int entries = image->colormap_entries > 256 ? 256 :
1801 (int)image->colormap_entries;
1802
1803 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1804 const png_uint_32 format = image->format;
1805 const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1806
1807 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1808 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1809 const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1810 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1811 # else
1812 # define afirst 0
1813 # endif
1814
1815 # ifdef PNG_FORMAT_BGR_SUPPORTED
1816 const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1817 # else
1818 # define bgr 0
1819 # endif
1820
1821 int i, num_trans;
1822 png_color palette[256];
1823 png_byte tRNS[256];
1824
1825 memset(tRNS, 255, (sizeof tRNS));
1826 memset(palette, 0, (sizeof palette));
1827
1828 for (i=num_trans=0; i<entries; ++i)
1829 {
1830 /* This gets automatically converted to sRGB with reversal of the
1831 * pre-multiplication if the color-map has an alpha channel.
1832 */
1833 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1834 {
1835 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1836
1837 entry += i * channels;
1838
1839 if ((channels & 1) != 0) /* no alpha */
1840 {
1841 if (channels >= 3) /* RGB */
1842 {
1843 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1844 entry[(2 ^ bgr)]);
1845 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1846 entry[1]);
1847 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1848 entry[bgr]);
1849 }
1850
1851 else /* Gray */
1852 palette[i].blue = palette[i].red = palette[i].green =
1853 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1854 }
1855
1856 else /* alpha */
1857 {
1858 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1859 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1860 png_uint_32 reciprocal = 0;
1861
1862 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1863 * this is designed to produce a value scaled to 255*65535 when
1864 * divided by 128 (i.e. asr 7).
1865 */
1866 if (alphabyte > 0 && alphabyte < 255)
1867 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1868
1869 tRNS[i] = alphabyte;
1870 if (alphabyte < 255)
1871 num_trans = i+1;
1872
1873 if (channels >= 3) /* RGB */
1874 {
1875 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1876 alpha, reciprocal);
1877 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1878 reciprocal);
1879 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1880 reciprocal);
1881 }
1882
1883 else /* gray */
1884 palette[i].blue = palette[i].red = palette[i].green =
1885 png_unpremultiply(entry[afirst], alpha, reciprocal);
1886 }
1887 }
1888
1889 else /* Color-map has sRGB values */
1890 {
1891 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1892
1893 entry += i * channels;
1894
1895 switch (channels)
1896 {
1897 case 4:
1898 tRNS[i] = entry[afirst ? 0 : 3];
1899 if (tRNS[i] < 255)
1900 num_trans = i+1;
1901 /* FALL THROUGH */
1902 case 3:
1903 palette[i].blue = entry[afirst + (2 ^ bgr)];
1904 palette[i].green = entry[afirst + 1];
1905 palette[i].red = entry[afirst + bgr];
1906 break;
1907
1908 case 2:
1909 tRNS[i] = entry[1 ^ afirst];
1910 if (tRNS[i] < 255)
1911 num_trans = i+1;
1912 /* FALL THROUGH */
1913 case 1:
1914 palette[i].blue = palette[i].red = palette[i].green =
1915 entry[afirst];
1916 break;
1917
1918 default:
1919 break;
1920 }
1921 }
1922 }
1923
1924 # ifdef afirst
1925 # undef afirst
1926 # endif
1927 # ifdef bgr
1928 # undef bgr
1929 # endif
1930
1931 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
1932 entries);
1933
1934 if (num_trans > 0)
1935 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
1936 num_trans, NULL);
1937
1938 image->colormap_entries = entries;
1939 }
1940
1941 static int
1942 png_image_write_main(png_voidp argument)
1943 {
1944 png_image_write_control *display = png_voidcast(png_image_write_control*,
1945 argument);
1946 png_imagep image = display->image;
1947 png_structrp png_ptr = image->opaque->png_ptr;
1948 png_inforp info_ptr = image->opaque->info_ptr;
1949 png_uint_32 format = image->format;
1950
1951 /* The following four ints are actually booleans */
1952 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
1953 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
1954 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
1955 int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);
1956
1957 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
1958 /* Make sure we error out on any bad situation */
1959 png_set_benign_errors(png_ptr, 0/*error*/);
1960 # endif
1961
1962 /* Default the 'row_stride' parameter if required. */
1963 if (display->row_stride == 0)
1964 display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);
1965
1966 /* Set the required transforms then write the rows in the correct order. */
1967 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
1968 {
1969 if (display->colormap != NULL && image->colormap_entries > 0)
1970 {
1971 png_uint_32 entries = image->colormap_entries;
1972
1973 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
1974 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
1975 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
1976 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
1977
1978 png_image_set_PLTE(display);
1979 }
1980
1981 else
1982 png_error(image->opaque->png_ptr,
1983 "no color-map for color-mapped image");
1984 }
1985
1986 else
1987 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
1988 write_16bit ? 16 : 8,
1989 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
1990 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
1991 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
1992
1993 /* Counter-intuitively the data transformations must be called *after*
1994 * png_write_info, not before as in the read code, but the 'set' functions
1995 * must still be called before. Just set the color space information, never
1996 * write an interlaced image.
1997 */
1998
1999 if (write_16bit != 0)
2000 {
2001 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2002 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2003
2004 if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2005 png_set_cHRM_fixed(png_ptr, info_ptr,
2006 /* color x y */
2007 /* white */ 31270, 32900,
2008 /* red */ 64000, 33000,
2009 /* green */ 30000, 60000,
2010 /* blue */ 15000, 6000
2011 );
2012 }
2013
2014 else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2015 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2016
2017 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2018 * space must still be gamma encoded.
2019 */
2020 else
2021 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2022
2023 /* Write the file header. */
2024 png_write_info(png_ptr, info_ptr);
2025
2026 /* Now set up the data transformations (*after* the header is written),
2027 * remove the handled transformations from the 'format' flags for checking.
2028 *
2029 * First check for a little endian system if writing 16-bit files.
2030 */
2031 if (write_16bit != 0)
2032 {
2033 PNG_CONST png_uint_16 le = 0x0001;
2034
2035 if ((*(png_const_bytep) & le) != 0)
2036 png_set_swap(png_ptr);
2037 }
2038
2039 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2040 if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2041 {
2042 if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2043 png_set_bgr(png_ptr);
2044 format &= ~PNG_FORMAT_FLAG_BGR;
2045 }
2046 # endif
2047
2048 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2049 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2050 {
2051 if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2052 png_set_swap_alpha(png_ptr);
2053 format &= ~PNG_FORMAT_FLAG_AFIRST;
2054 }
2055 # endif
2056
2057 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2058 * above, but the application data is still byte packed.
2059 */
2060 if (colormap != 0 && image->colormap_entries <= 16)
2061 png_set_packing(png_ptr);
2062
2063 /* That should have handled all (both) the transforms. */
2064 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2065 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2066 png_error(png_ptr, "png_write_image: unsupported transformation");
2067
2068 {
2069 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2070 ptrdiff_t row_bytes = display->row_stride;
2071
2072 if (linear != 0)
2073 row_bytes *= (sizeof (png_uint_16));
2074
2075 if (row_bytes < 0)
2076 row += (image->height-1) * (-row_bytes);
2077
2078 display->first_row = row;
2079 display->row_bytes = row_bytes;
2080 }
2081
2082 /* Apply 'fast' options if the flag is set. */
2083 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2084 {
2085 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2086 /* NOTE: determined by experiment using pngstest, this reflects some
2087 * balance between the time to write the image once and the time to read
2088 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2089 * total (user) time on a heavily loaded system.
2090 */
2091 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2092 png_set_compression_level(png_ptr, 3);
2093 # endif
2094 }
2095
2096 /* Check for the cases that currently require a pre-transform on the row
2097 * before it is written. This only applies when the input is 16-bit and
2098 * either there is an alpha channel or it is converted to 8-bit.
2099 */
2100 if ((linear != 0 && alpha != 0 ) ||
2101 (colormap == 0 && display->convert_to_8bit != 0))
2102 {
2103 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2104 png_get_rowbytes(png_ptr, info_ptr)));
2105 int result;
2106
2107 display->local_row = row;
2108 if (write_16bit != 0)
2109 result = png_safe_execute(image, png_write_image_16bit, display);
2110 else
2111 result = png_safe_execute(image, png_write_image_8bit, display);
2112 display->local_row = NULL;
2113
2114 png_free(png_ptr, row);
2115
2116 /* Skip the 'write_end' on error: */
2117 if (result == 0)
2118 return 0;
2119 }
2120
2121 /* Otherwise this is the case where the input is in a format currently
2122 * supported by the rest of the libpng write code; call it directly.
2123 */
2124 else
2125 {
2126 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2127 ptrdiff_t row_bytes = display->row_bytes;
2128 png_uint_32 y = image->height;
2129
2130 while (y-- > 0)
2131 {
2132 png_write_row(png_ptr, row);
2133 row += row_bytes;
2134 }
2135 }
2136
2137 png_write_end(png_ptr, info_ptr);
2138 return 1;
2139 }
2140
2141 int PNGAPI
2142 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2143 const void *buffer, png_int_32 row_stride, const void *colormap)
2144 {
2145 /* Write the image to the given (FILE*). */
2146 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2147 {
2148 if (file != NULL)
2149 {
2150 if (png_image_write_init(image) != 0)
2151 {
2152 png_image_write_control display;
2153 int result;
2154
2155 /* This is slightly evil, but png_init_io doesn't do anything other
2156 * than this and we haven't changed the standard IO functions so
2157 * this saves a 'safe' function.
2158 */
2159 image->opaque->png_ptr->io_ptr = file;
2160
2161 memset(&display, 0, (sizeof display));
2162 display.image = image;
2163 display.buffer = buffer;
2164 display.row_stride = row_stride;
2165 display.colormap = colormap;
2166 display.convert_to_8bit = convert_to_8bit;
2167
2168 result = png_safe_execute(image, png_image_write_main, &display);
2169 png_image_free(image);
2170 return result;
2171 }
2172
2173 else
2174 return 0;
2175 }
2176
2177 else
2178 return png_image_error(image,
2179 "png_image_write_to_stdio: invalid argument");
2180 }
2181
2182 else if (image != NULL)
2183 return png_image_error(image,
2184 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2185
2186 else
2187 return 0;
2188 }
2189
2190 int PNGAPI
2191 png_image_write_to_file(png_imagep image, const char *file_name,
2192 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2193 const void *colormap)
2194 {
2195 /* Write the image to the named file. */
2196 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2197 {
2198 if (file_name != NULL)
2199 {
2200 FILE *fp = fopen(file_name, "wb");
2201
2202 if (fp != NULL)
2203 {
2204 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2205 row_stride, colormap) != 0)
2206 {
2207 int error; /* from fflush/fclose */
2208
2209 /* Make sure the file is flushed correctly. */
2210 if (fflush(fp) == 0 && ferror(fp) == 0)
2211 {
2212 if (fclose(fp) == 0)
2213 return 1;
2214
2215 error = errno; /* from fclose */
2216 }
2217
2218 else
2219 {
2220 error = errno; /* from fflush or ferror */
2221 (void)fclose(fp);
2222 }
2223
2224 (void)remove(file_name);
2225 /* The image has already been cleaned up; this is just used to
2226 * set the error (because the original write succeeded).
2227 */
2228 return png_image_error(image, strerror(error));
2229 }
2230
2231 else
2232 {
2233 /* Clean up: just the opened file. */
2234 (void)fclose(fp);
2235 (void)remove(file_name);
2236 return 0;
2237 }
2238 }
2239
2240 else
2241 return png_image_error(image, strerror(errno));
2242 }
2243
2244 else
2245 return png_image_error(image,
2246 "png_image_write_to_file: invalid argument");
2247 }
2248
2249 else if (image != NULL)
2250 return png_image_error(image,
2251 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2252
2253 else
2254 return 0;
2255 }
2256 # endif /* STDIO */
2257 #endif /* SIMPLIFIED_WRITE */
2258 #endif /* WRITE */