2 /* pngwrite.c - general routines to write a PNG file
4 * Copyright (c) 2018-2023 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.
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
15 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
17 #endif /* SIMPLIFIED_WRITE_STDIO */
19 #ifdef PNG_WRITE_SUPPORTED
21 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
22 /* Write out all the unknown chunks for the current given location */
24 write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
27 if (info_ptr->unknown_chunks_num != 0)
29 png_const_unknown_chunkp up;
31 png_debug(5, "writing extra chunks");
33 for (up = info_ptr->unknown_chunks;
34 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
36 if ((up->location & where) != 0)
38 /* If per-chunk unknown chunk handling is enabled use it, otherwise
39 * just write the chunks the application has set.
41 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
42 int keep = png_handle_as_unknown(png_ptr, up->name);
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
51 * The default handling is also slightly weird - it is not possible to
52 * stop the writing of all unsafe-to-copy chunks!
54 * TODO: REVIEW: this would seem to be a bug.
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)))
63 /* TODO: review, what is wrong with a zero length unknown chunk? */
65 png_warning(png_ptr, "Writing zero-length unknown chunk");
67 png_write_chunk(png_ptr, up->name, up->data, up->size);
72 #endif /* WRITE_UNKNOWN_CHUNKS */
74 /* Writes all the PNG information. This is the suggested way to use the
75 * library. If you have a new chunk to add, make a function to write it,
76 * and put it in the correct location here. If you want the chunk written
77 * after the image data, put it in png_write_end(). I strongly encourage
78 * you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before
79 * writing the chunk, as that will keep the code from breaking if you want
80 * to just write a plain PNG file. If you have long comments, I suggest
81 * writing them in png_write_end(), and compressing them.
84 png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
86 png_debug(1, "in png_write_info_before_PLTE");
88 if (png_ptr == NULL || info_ptr == NULL)
91 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
93 /* Write PNG signature */
94 png_write_sig(png_ptr);
96 #ifdef PNG_MNG_FEATURES_SUPPORTED
97 if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
98 png_ptr->mng_features_permitted != 0)
101 "MNG features are not allowed in a PNG datastream");
102 png_ptr->mng_features_permitted = 0;
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
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.
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.)
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'
131 #ifdef PNG_WRITE_APNG_SUPPORTED
132 if (info_ptr->valid & PNG_INFO_acTL)
133 png_write_acTL(png_ptr, info_ptr->num_frames, info_ptr->num_plays);
135 #ifdef PNG_GAMMA_SUPPORTED
136 # ifdef PNG_WRITE_gAMA_SUPPORTED
137 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
138 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
139 (info_ptr->valid & PNG_INFO_gAMA) != 0)
140 png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
144 #ifdef PNG_COLORSPACE_SUPPORTED
145 /* Write only one of sRGB or an ICC profile. If a profile was supplied
146 * and it matches one of the known sRGB ones issue a warning.
148 # ifdef PNG_WRITE_iCCP_SUPPORTED
149 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
150 (info_ptr->valid & PNG_INFO_iCCP) != 0)
152 # ifdef PNG_WRITE_sRGB_SUPPORTED
153 if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
154 png_app_warning(png_ptr,
155 "profile matches sRGB but writing iCCP instead");
158 png_write_iCCP(png_ptr, info_ptr->iccp_name,
159 info_ptr->iccp_profile);
161 # ifdef PNG_WRITE_sRGB_SUPPORTED
166 # ifdef PNG_WRITE_sRGB_SUPPORTED
167 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
168 (info_ptr->valid & PNG_INFO_sRGB) != 0)
169 png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
170 # endif /* WRITE_sRGB */
171 #endif /* COLORSPACE */
173 #ifdef PNG_WRITE_sBIT_SUPPORTED
174 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
175 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
178 #ifdef PNG_COLORSPACE_SUPPORTED
179 # ifdef PNG_WRITE_cHRM_SUPPORTED
180 if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
181 (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
182 (info_ptr->valid & PNG_INFO_cHRM) != 0)
183 png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
187 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
188 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
191 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
196 png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
198 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
202 png_debug(1, "in png_write_info");
204 if (png_ptr == NULL || info_ptr == NULL)
207 png_write_info_before_PLTE(png_ptr, info_ptr);
209 if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
210 png_write_PLTE(png_ptr, info_ptr->palette,
211 (png_uint_32)info_ptr->num_palette);
213 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
214 png_error(png_ptr, "Valid palette required for paletted images");
216 #ifdef PNG_WRITE_tRNS_SUPPORTED
217 if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
219 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
220 /* Invert the alpha channel (in tRNS) */
221 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
222 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
226 jend = info_ptr->num_trans;
227 if (jend > PNG_MAX_PALETTE_LENGTH)
228 jend = PNG_MAX_PALETTE_LENGTH;
230 for (j = 0; j<jend; ++j)
231 info_ptr->trans_alpha[j] =
232 (png_byte)(255 - info_ptr->trans_alpha[j]);
235 png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
236 info_ptr->num_trans, info_ptr->color_type);
239 #ifdef PNG_WRITE_bKGD_SUPPORTED
240 if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
241 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
244 #ifdef PNG_WRITE_eXIf_SUPPORTED
245 if ((info_ptr->valid & PNG_INFO_eXIf) != 0)
247 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
248 png_ptr->mode |= PNG_WROTE_eXIf;
252 #ifdef PNG_WRITE_hIST_SUPPORTED
253 if ((info_ptr->valid & PNG_INFO_hIST) != 0)
254 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
257 #ifdef PNG_WRITE_oFFs_SUPPORTED
258 if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
259 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
260 info_ptr->offset_unit_type);
263 #ifdef PNG_WRITE_pCAL_SUPPORTED
264 if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
265 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
266 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
267 info_ptr->pcal_units, info_ptr->pcal_params);
270 #ifdef PNG_WRITE_sCAL_SUPPORTED
271 if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
272 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
273 info_ptr->scal_s_width, info_ptr->scal_s_height);
276 #ifdef PNG_WRITE_pHYs_SUPPORTED
277 if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
278 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
279 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
282 #ifdef PNG_WRITE_tIME_SUPPORTED
283 if ((info_ptr->valid & PNG_INFO_tIME) != 0)
285 png_write_tIME(png_ptr, &(info_ptr->mod_time));
286 png_ptr->mode |= PNG_WROTE_tIME;
290 #ifdef PNG_WRITE_sPLT_SUPPORTED
291 if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
292 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
293 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
296 #ifdef PNG_WRITE_TEXT_SUPPORTED
297 /* Check to see if we need to write text chunks */
298 for (i = 0; i < info_ptr->num_text; i++)
300 png_debug2(2, "Writing header text chunk %d, type %d", i,
301 info_ptr->text[i].compression);
302 /* An internationalized chunk? */
303 if (info_ptr->text[i].compression > 0)
305 #ifdef PNG_WRITE_iTXt_SUPPORTED
306 /* Write international chunk */
307 png_write_iTXt(png_ptr,
308 info_ptr->text[i].compression,
309 info_ptr->text[i].key,
310 info_ptr->text[i].lang,
311 info_ptr->text[i].lang_key,
312 info_ptr->text[i].text);
313 /* Mark this chunk as written */
314 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
315 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
317 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
319 png_warning(png_ptr, "Unable to write international text");
323 /* If we want a compressed text chunk */
324 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
326 #ifdef PNG_WRITE_zTXt_SUPPORTED
327 /* Write compressed chunk */
328 png_write_zTXt(png_ptr, info_ptr->text[i].key,
329 info_ptr->text[i].text, info_ptr->text[i].compression);
330 /* Mark this chunk as written */
331 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
333 png_warning(png_ptr, "Unable to write compressed text");
337 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
339 #ifdef PNG_WRITE_tEXt_SUPPORTED
340 /* Write uncompressed chunk */
341 png_write_tEXt(png_ptr, info_ptr->text[i].key,
342 info_ptr->text[i].text,
344 /* Mark this chunk as written */
345 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
348 png_warning(png_ptr, "Unable to write uncompressed text");
354 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
355 write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
359 /* Writes the end of the PNG file. If you don't want to write comments or
360 * time information, you can pass NULL for info. If you already wrote these
361 * in png_write_info(), do not write them again here. If you have long
362 * comments, I suggest writing them here, and compressing them.
365 png_write_end(png_structrp png_ptr, png_inforp info_ptr)
367 png_debug(1, "in png_write_end");
372 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
373 png_error(png_ptr, "No IDATs written into file");
375 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
376 if (png_ptr->num_palette_max > png_ptr->num_palette)
377 png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
380 #ifdef PNG_WRITE_APNG_SUPPORTED
381 if (png_ptr->num_frames_written != png_ptr->num_frames_to_write)
382 png_error(png_ptr, "Not enough frames written");
385 /* See if user wants us to write information chunks */
386 if (info_ptr != NULL)
388 #ifdef PNG_WRITE_TEXT_SUPPORTED
389 int i; /* local index variable */
391 #ifdef PNG_WRITE_tIME_SUPPORTED
392 /* Check to see if user has supplied a time chunk */
393 if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
394 (png_ptr->mode & PNG_WROTE_tIME) == 0)
395 png_write_tIME(png_ptr, &(info_ptr->mod_time));
398 #ifdef PNG_WRITE_TEXT_SUPPORTED
399 /* Loop through comment chunks */
400 for (i = 0; i < info_ptr->num_text; i++)
402 png_debug2(2, "Writing trailer text chunk %d, type %d", i,
403 info_ptr->text[i].compression);
404 /* An internationalized chunk? */
405 if (info_ptr->text[i].compression > 0)
407 #ifdef PNG_WRITE_iTXt_SUPPORTED
408 /* Write international chunk */
409 png_write_iTXt(png_ptr,
410 info_ptr->text[i].compression,
411 info_ptr->text[i].key,
412 info_ptr->text[i].lang,
413 info_ptr->text[i].lang_key,
414 info_ptr->text[i].text);
415 /* Mark this chunk as written */
416 if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
417 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
419 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
421 png_warning(png_ptr, "Unable to write international text");
425 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
427 #ifdef PNG_WRITE_zTXt_SUPPORTED
428 /* Write compressed chunk */
429 png_write_zTXt(png_ptr, info_ptr->text[i].key,
430 info_ptr->text[i].text, info_ptr->text[i].compression);
431 /* Mark this chunk as written */
432 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
434 png_warning(png_ptr, "Unable to write compressed text");
438 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
440 #ifdef PNG_WRITE_tEXt_SUPPORTED
441 /* Write uncompressed chunk */
442 png_write_tEXt(png_ptr, info_ptr->text[i].key,
443 info_ptr->text[i].text, 0);
444 /* Mark this chunk as written */
445 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
447 png_warning(png_ptr, "Unable to write uncompressed text");
453 #ifdef PNG_WRITE_eXIf_SUPPORTED
454 if ((info_ptr->valid & PNG_INFO_eXIf) != 0 &&
455 (png_ptr->mode & PNG_WROTE_eXIf) == 0)
456 png_write_eXIf(png_ptr, info_ptr->exif, info_ptr->num_exif);
459 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
460 write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
464 png_ptr->mode |= PNG_AFTER_IDAT;
466 /* Write end of PNG file */
467 png_write_IEND(png_ptr);
469 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
470 * and restored again in libpng-1.2.30, may cause some applications that
471 * do not set png_ptr->output_flush_fn to crash. If your application
472 * experiences a problem, please try building libpng with
473 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
474 * png-mng-implement at lists.sf.net .
476 #ifdef PNG_WRITE_FLUSH_SUPPORTED
477 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
483 #ifdef PNG_CONVERT_tIME_SUPPORTED
485 png_convert_from_struct_tm(png_timep ptime, const struct tm * ttime)
487 png_debug(1, "in png_convert_from_struct_tm");
489 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
490 ptime->month = (png_byte)(ttime->tm_mon + 1);
491 ptime->day = (png_byte)ttime->tm_mday;
492 ptime->hour = (png_byte)ttime->tm_hour;
493 ptime->minute = (png_byte)ttime->tm_min;
494 ptime->second = (png_byte)ttime->tm_sec;
498 png_convert_from_time_t(png_timep ptime, time_t ttime)
502 png_debug(1, "in png_convert_from_time_t");
504 tbuf = gmtime(&ttime);
507 /* TODO: add a safe function which takes a png_ptr argument and raises
508 * a png_error if the ttime argument is invalid and the call to gmtime
509 * fails as a consequence.
511 memset(ptime, 0, sizeof(*ptime));
515 png_convert_from_struct_tm(ptime, tbuf);
519 /* Initialize png_ptr structure, and allocate any memory needed */
520 PNG_FUNCTION(png_structp,PNGAPI
521 png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
522 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
524 #ifndef PNG_USER_MEM_SUPPORTED
525 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
526 error_fn, warn_fn, NULL, NULL, NULL);
528 return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
529 warn_fn, NULL, NULL, NULL);
532 /* Alternate initialize png_ptr structure, and allocate any memory needed */
533 PNG_FUNCTION(png_structp,PNGAPI
534 png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
535 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
536 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
538 png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
539 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
540 #endif /* USER_MEM */
543 /* Set the zlib control values to defaults; they can be overridden by the
544 * application after the struct has been created.
546 png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
548 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
549 * pngwutil.c defaults it according to whether or not filters will be
550 * used, and ignores this setting.
552 png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
553 png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
554 png_ptr->zlib_mem_level = 8;
555 png_ptr->zlib_window_bits = 15;
556 png_ptr->zlib_method = 8;
558 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
559 png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
560 png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
561 png_ptr->zlib_text_mem_level = 8;
562 png_ptr->zlib_text_window_bits = 15;
563 png_ptr->zlib_text_method = 8;
564 #endif /* WRITE_COMPRESSED_TEXT */
566 /* This is a highly dubious configuration option; by default it is off,
567 * but it may be appropriate for private builds that are testing
568 * extensions not conformant to the current specification, or of
569 * applications that must not fail to write at all costs!
571 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
572 /* In stable builds only warn if an application error can be completely
575 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
578 /* App warnings are warnings in release (or release candidate) builds but
579 * are errors during development.
581 #if PNG_RELEASE_BUILD
582 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
585 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
586 * do it itself) avoiding setting the default function if it is not
589 png_set_write_fn(png_ptr, NULL, NULL, NULL);
596 /* Write a few rows of image data. If the image is interlaced,
597 * either you will have to write the 7 sub images, or, if you
598 * have called png_set_interlace_handling(), you will have to
599 * "write" the image seven times.
602 png_write_rows(png_structrp png_ptr, png_bytepp row,
603 png_uint_32 num_rows)
605 png_uint_32 i; /* row counter */
606 png_bytepp rp; /* row pointer */
608 png_debug(1, "in png_write_rows");
613 /* Loop through the rows */
614 for (i = 0, rp = row; i < num_rows; i++, rp++)
616 png_write_row(png_ptr, *rp);
620 /* Write the image. You only need to call this function once, even
621 * if you are writing an interlaced image.
624 png_write_image(png_structrp png_ptr, png_bytepp image)
626 png_uint_32 i; /* row index */
627 int pass, num_pass; /* pass variables */
628 png_bytepp rp; /* points to current row */
633 png_debug(1, "in png_write_image");
635 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
636 /* Initialize interlace handling. If image is not interlaced,
637 * this will set pass to 1
639 num_pass = png_set_interlace_handling(png_ptr);
643 /* Loop through passes */
644 for (pass = 0; pass < num_pass; pass++)
646 /* Loop through image */
647 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
649 png_write_row(png_ptr, *rp);
654 #ifdef PNG_MNG_FEATURES_SUPPORTED
655 /* Performs intrapixel differencing */
657 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
659 png_debug(1, "in png_do_write_intrapixel");
661 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
664 png_uint_32 row_width = row_info->width;
665 if (row_info->bit_depth == 8)
670 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
673 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
679 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
681 *(rp) = (png_byte)(*rp - *(rp + 1));
682 *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
686 #ifdef PNG_WRITE_16BIT_SUPPORTED
687 else if (row_info->bit_depth == 16)
692 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
695 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
701 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
703 png_uint_32 s0 = (png_uint_32)(*(rp ) << 8) | *(rp + 1);
704 png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
705 png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
706 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
707 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
708 *(rp ) = (png_byte)(red >> 8);
709 *(rp + 1) = (png_byte)red;
710 *(rp + 4) = (png_byte)(blue >> 8);
711 *(rp + 5) = (png_byte)blue;
714 #endif /* WRITE_16BIT */
717 #endif /* MNG_FEATURES */
719 /* Called by user to write a row of image data */
721 png_write_row(png_structrp png_ptr, png_const_bytep row)
723 /* 1.5.6: moved from png_struct to be a local structure: */
724 png_row_info row_info;
729 png_debug2(1, "in png_write_row (row %u, pass %d)",
730 png_ptr->row_number, png_ptr->pass);
732 /* Initialize transformations and other stuff if first time */
733 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
735 /* Make sure we wrote the header info */
736 if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
738 "png_write_info was never called before png_write_row");
740 /* Check for transforms that have been set but were defined out */
741 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
742 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
743 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
746 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
747 if ((png_ptr->transformations & PNG_FILLER) != 0)
748 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
750 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
751 defined(PNG_READ_PACKSWAP_SUPPORTED)
752 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
754 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
757 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
758 if ((png_ptr->transformations & PNG_PACK) != 0)
759 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
762 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
763 if ((png_ptr->transformations & PNG_SHIFT) != 0)
764 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
767 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
768 if ((png_ptr->transformations & PNG_BGR) != 0)
769 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
772 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
773 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
774 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
777 png_write_start_row(png_ptr);
780 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
781 /* If interlaced and not interested in row, return */
782 if (png_ptr->interlaced != 0 &&
783 (png_ptr->transformations & PNG_INTERLACE) != 0)
785 switch (png_ptr->pass)
788 if ((png_ptr->row_number & 0x07) != 0)
790 png_write_finish_row(png_ptr);
796 if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
798 png_write_finish_row(png_ptr);
804 if ((png_ptr->row_number & 0x07) != 4)
806 png_write_finish_row(png_ptr);
812 if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
814 png_write_finish_row(png_ptr);
820 if ((png_ptr->row_number & 0x03) != 2)
822 png_write_finish_row(png_ptr);
828 if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
830 png_write_finish_row(png_ptr);
836 if ((png_ptr->row_number & 0x01) == 0)
838 png_write_finish_row(png_ptr);
843 default: /* error: ignore it */
849 /* Set up row info for transformations */
850 row_info.color_type = png_ptr->color_type;
851 row_info.width = png_ptr->usr_width;
852 row_info.channels = png_ptr->usr_channels;
853 row_info.bit_depth = png_ptr->usr_bit_depth;
854 row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
855 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
857 png_debug1(3, "row_info->color_type = %d", row_info.color_type);
858 png_debug1(3, "row_info->width = %u", row_info.width);
859 png_debug1(3, "row_info->channels = %d", row_info.channels);
860 png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
861 png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
862 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
864 /* Copy user's row into buffer, leaving room for filter byte. */
865 memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
867 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
868 /* Handle interlacing */
869 if (png_ptr->interlaced && png_ptr->pass < 6 &&
870 (png_ptr->transformations & PNG_INTERLACE) != 0)
872 png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
873 /* This should always get caught above, but still ... */
874 if (row_info.width == 0)
876 png_write_finish_row(png_ptr);
882 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
883 /* Handle other transformations */
884 if (png_ptr->transformations != 0)
885 png_do_write_transformations(png_ptr, &row_info);
888 /* At this point the row_info pixel depth must match the 'transformed' depth,
889 * which is also the output depth.
891 if (row_info.pixel_depth != png_ptr->pixel_depth ||
892 row_info.pixel_depth != png_ptr->transformed_pixel_depth)
893 png_error(png_ptr, "internal write transform logic error");
895 #ifdef PNG_MNG_FEATURES_SUPPORTED
896 /* Write filter_method 64 (intrapixel differencing) only if
897 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
898 * 2. Libpng did not write a PNG signature (this filter_method is only
899 * used in PNG datastreams that are embedded in MNG datastreams) and
900 * 3. The application called png_permit_mng_features with a mask that
901 * included PNG_FLAG_MNG_FILTER_64 and
902 * 4. The filter_method is 64 and
903 * 5. The color_type is RGB or RGBA
905 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
906 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
908 /* Intrapixel differencing */
909 png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
913 /* Added at libpng-1.5.10 */
914 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
915 /* Check for out-of-range palette index */
916 if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
917 png_ptr->num_palette_max >= 0)
918 png_do_check_palette_indexes(png_ptr, &row_info);
921 /* Find a filter if necessary, filter the row and write it out. */
922 png_write_find_filter(png_ptr, &row_info);
924 if (png_ptr->write_row_fn != NULL)
925 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
928 #ifdef PNG_WRITE_FLUSH_SUPPORTED
929 /* Set the automatic flush interval or 0 to turn flushing off */
931 png_set_flush(png_structrp png_ptr, int nrows)
933 png_debug(1, "in png_set_flush");
938 png_ptr->flush_dist = (nrows < 0 ? 0 : (png_uint_32)nrows);
941 /* Flush the current output buffers now */
943 png_write_flush(png_structrp png_ptr)
945 png_debug(1, "in png_write_flush");
950 /* We have already written out all of the data */
951 if (png_ptr->row_number >= png_ptr->num_rows)
954 png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
955 png_ptr->flush_rows = 0;
958 #endif /* WRITE_FLUSH */
960 /* Free any memory used in png_ptr struct without freeing the struct itself. */
962 png_write_destroy(png_structrp png_ptr)
964 png_debug(1, "in png_write_destroy");
966 /* Free any memory zlib uses */
967 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
968 deflateEnd(&png_ptr->zstream);
970 /* Free our memory. png_free checks NULL for us. */
971 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
972 png_free(png_ptr, png_ptr->row_buf);
973 png_ptr->row_buf = NULL;
974 #ifdef PNG_WRITE_FILTER_SUPPORTED
975 png_free(png_ptr, png_ptr->prev_row);
976 png_free(png_ptr, png_ptr->try_row);
977 png_free(png_ptr, png_ptr->tst_row);
978 png_ptr->prev_row = NULL;
979 png_ptr->try_row = NULL;
980 png_ptr->tst_row = NULL;
983 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
984 png_free(png_ptr, png_ptr->chunk_list);
985 png_ptr->chunk_list = NULL;
988 /* The error handling and memory handling information is left intact at this
989 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
990 * for how this happens.
994 /* Free all memory used by the write.
995 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
996 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
997 * the passed in info_structs but it would quietly fail to free any of the data
998 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
1002 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
1004 png_debug(1, "in png_destroy_write_struct");
1006 if (png_ptr_ptr != NULL)
1008 png_structrp png_ptr = *png_ptr_ptr;
1010 if (png_ptr != NULL) /* added in libpng 1.6.0 */
1012 png_destroy_info_struct(png_ptr, info_ptr_ptr);
1014 *png_ptr_ptr = NULL;
1015 png_write_destroy(png_ptr);
1016 png_destroy_png_struct(png_ptr);
1021 /* Allow the application to select one or more row filters to use. */
1023 png_set_filter(png_structrp png_ptr, int method, int filters)
1025 png_debug(1, "in png_set_filter");
1027 if (png_ptr == NULL)
1030 #ifdef PNG_MNG_FEATURES_SUPPORTED
1031 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
1032 (method == PNG_INTRAPIXEL_DIFFERENCING))
1033 method = PNG_FILTER_TYPE_BASE;
1036 if (method == PNG_FILTER_TYPE_BASE)
1038 switch (filters & (PNG_ALL_FILTERS | 0x07))
1040 #ifdef PNG_WRITE_FILTER_SUPPORTED
1043 case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
1044 #endif /* WRITE_FILTER */
1047 /* 'switch ~ case' is dead code.
1048 * If filters is #PNG_FILTER_VALUE_NONE, #PNG_FILTER_VALUE_SUB ...,
1049 * filter flag will be assigned to 'png_ptr->do_filter'. But
1050 * 'png_ptr->do_filter' is overwritten as 'filters' at below code.
1051 * Issue code(#1155) is 'png_ptr->do_filter = (png_byte)filters;'.
1052 * So the result of 'switch ~ case' has been lost at the line.
1053 * To keep the value of 'switch ~ case', we fixed it to apply
1054 * the result into 'filters'.
1055 * It will be updated into 'png_ptr->do_filter' at #1155 line.
1057 case PNG_FILTER_VALUE_NONE:
1058 filters = PNG_FILTER_NONE; break;
1060 case PNG_FILTER_VALUE_NONE:
1061 png_ptr->do_filter = PNG_FILTER_NONE; break;
1062 #endif /* __TIZEN__ */
1064 #ifdef PNG_WRITE_FILTER_SUPPORTED
1066 case PNG_FILTER_VALUE_SUB:
1067 filters = PNG_FILTER_SUB; break;
1069 case PNG_FILTER_VALUE_UP:
1070 filters = PNG_FILTER_UP; break;
1072 case PNG_FILTER_VALUE_AVG:
1073 filters = PNG_FILTER_AVG; break;
1075 case PNG_FILTER_VALUE_PAETH:
1076 filters = PNG_FILTER_PAETH; break;
1078 case PNG_FILTER_VALUE_SUB:
1079 png_ptr->do_filter = PNG_FILTER_SUB; break;
1081 case PNG_FILTER_VALUE_UP:
1082 png_ptr->do_filter = PNG_FILTER_UP; break;
1084 case PNG_FILTER_VALUE_AVG:
1085 png_ptr->do_filter = PNG_FILTER_AVG; break;
1087 case PNG_FILTER_VALUE_PAETH:
1088 png_ptr->do_filter = PNG_FILTER_PAETH; break;
1089 #endif /* __TIZEN__ */
1091 png_ptr->do_filter = (png_byte)filters; break;
1094 png_app_error(png_ptr, "Unknown row filter for method 0");
1095 #endif /* WRITE_FILTER */
1098 #ifdef PNG_WRITE_FILTER_SUPPORTED
1099 /* If we have allocated the row_buf, this means we have already started
1100 * with the image and we should have allocated all of the filter buffers
1101 * that have been selected. If prev_row isn't already allocated, then
1102 * it is too late to start using the filters that need it, since we
1103 * will be missing the data in the previous row. If an application
1104 * wants to start and stop using particular filters during compression,
1105 * it should start out with all of the filters, and then remove them
1106 * or add them back after the start of compression.
1108 * NOTE: this is a nasty constraint on the code, because it means that the
1109 * prev_row buffer must be maintained even if there are currently no
1110 * 'prev_row' requiring filters active.
1112 if (png_ptr->row_buf != NULL)
1115 png_alloc_size_t buf_size;
1117 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1118 * images cannot benefit from certain filters. If this isn't done here
1119 * the check below will fire on 1 pixel high images.
1121 if (png_ptr->height == 1)
1122 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1124 if (png_ptr->width == 1)
1125 filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1127 if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
1128 && png_ptr->prev_row == NULL)
1130 /* This is the error case, however it is benign - the previous row
1131 * is not available so the filter can't be used. Just warn here.
1133 png_app_warning(png_ptr,
1134 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1135 filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
1140 if (filters & PNG_FILTER_SUB)
1143 if (filters & PNG_FILTER_UP)
1146 if (filters & PNG_FILTER_AVG)
1149 if (filters & PNG_FILTER_PAETH)
1152 /* Allocate needed row buffers if they have not already been
1155 buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
1156 png_ptr->width) + 1;
1158 if (png_ptr->try_row == NULL)
1159 png_ptr->try_row = png_voidcast(png_bytep,
1160 png_malloc(png_ptr, buf_size));
1162 if (num_filters > 1)
1164 if (png_ptr->tst_row == NULL)
1165 png_ptr->tst_row = png_voidcast(png_bytep,
1166 png_malloc(png_ptr, buf_size));
1169 png_ptr->do_filter = (png_byte)filters;
1173 png_error(png_ptr, "Unknown custom filter method");
1176 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1177 /* Provide floating and fixed point APIs */
1178 #ifdef PNG_FLOATING_POINT_SUPPORTED
1180 png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
1181 int num_weights, png_const_doublep filter_weights,
1182 png_const_doublep filter_costs)
1185 PNG_UNUSED(heuristic_method)
1186 PNG_UNUSED(num_weights)
1187 PNG_UNUSED(filter_weights)
1188 PNG_UNUSED(filter_costs)
1190 #endif /* FLOATING_POINT */
1192 #ifdef PNG_FIXED_POINT_SUPPORTED
1194 png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
1195 int num_weights, png_const_fixed_point_p filter_weights,
1196 png_const_fixed_point_p filter_costs)
1199 PNG_UNUSED(heuristic_method)
1200 PNG_UNUSED(num_weights)
1201 PNG_UNUSED(filter_weights)
1202 PNG_UNUSED(filter_costs)
1204 #endif /* FIXED_POINT */
1205 #endif /* WRITE_WEIGHTED_FILTER */
1207 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1209 png_set_compression_level(png_structrp png_ptr, int level)
1211 png_debug(1, "in png_set_compression_level");
1213 if (png_ptr == NULL)
1216 png_ptr->zlib_level = level;
1220 png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
1222 png_debug(1, "in png_set_compression_mem_level");
1224 if (png_ptr == NULL)
1227 png_ptr->zlib_mem_level = mem_level;
1231 png_set_compression_strategy(png_structrp png_ptr, int strategy)
1233 png_debug(1, "in png_set_compression_strategy");
1235 if (png_ptr == NULL)
1238 /* The flag setting here prevents the libpng dynamic selection of strategy.
1240 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1241 png_ptr->zlib_strategy = strategy;
1244 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1245 * smaller value of window_bits if it can do so safely.
1248 png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
1250 if (png_ptr == NULL)
1253 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1254 * meant that negative window bits values could be selected that would cause
1255 * libpng to write a non-standard PNG file with raw deflate or gzip
1256 * compressed IDAT or ancillary chunks. Such files can be read and there is
1257 * no warning on read, so this seems like a very bad idea.
1259 if (window_bits > 15)
1261 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1265 else if (window_bits < 8)
1267 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1271 png_ptr->zlib_window_bits = window_bits;
1275 png_set_compression_method(png_structrp png_ptr, int method)
1277 png_debug(1, "in png_set_compression_method");
1279 if (png_ptr == NULL)
1282 /* This would produce an invalid PNG file if it worked, but it doesn't and
1283 * deflate will fault it, so it is harmless to just warn here.
1286 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1288 png_ptr->zlib_method = method;
1290 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1292 /* The following were added to libpng-1.5.4 */
1293 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1295 png_set_text_compression_level(png_structrp png_ptr, int level)
1297 png_debug(1, "in png_set_text_compression_level");
1299 if (png_ptr == NULL)
1302 png_ptr->zlib_text_level = level;
1306 png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
1308 png_debug(1, "in png_set_text_compression_mem_level");
1310 if (png_ptr == NULL)
1313 png_ptr->zlib_text_mem_level = mem_level;
1317 png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
1319 png_debug(1, "in png_set_text_compression_strategy");
1321 if (png_ptr == NULL)
1324 png_ptr->zlib_text_strategy = strategy;
1327 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1328 * smaller value of window_bits if it can do so safely.
1331 png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
1333 if (png_ptr == NULL)
1336 if (window_bits > 15)
1338 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1342 else if (window_bits < 8)
1344 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1348 png_ptr->zlib_text_window_bits = window_bits;
1352 png_set_text_compression_method(png_structrp png_ptr, int method)
1354 png_debug(1, "in png_set_text_compression_method");
1356 if (png_ptr == NULL)
1360 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1362 png_ptr->zlib_text_method = method;
1364 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1365 /* end of API added to libpng-1.5.4 */
1368 png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
1370 if (png_ptr == NULL)
1373 png_ptr->write_row_fn = write_row_fn;
1376 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1378 png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1379 write_user_transform_fn)
1381 png_debug(1, "in png_set_write_user_transform_fn");
1383 if (png_ptr == NULL)
1386 png_ptr->transformations |= PNG_USER_TRANSFORM;
1387 png_ptr->write_user_transform_fn = write_user_transform_fn;
1392 #ifdef PNG_INFO_IMAGE_SUPPORTED
1394 png_write_png(png_structrp png_ptr, png_inforp info_ptr,
1395 int transforms, voidp params)
1397 if (png_ptr == NULL || info_ptr == NULL)
1400 if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
1402 png_app_error(png_ptr, "no rows for png_write_image to write");
1406 /* Write the file header information. */
1407 png_write_info(png_ptr, info_ptr);
1409 /* ------ these transformations don't touch the info structure ------- */
1411 /* Invert monochrome pixels */
1412 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
1413 #ifdef PNG_WRITE_INVERT_SUPPORTED
1414 png_set_invert_mono(png_ptr);
1416 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
1419 /* Shift the pixels up to a legal bit depth and fill in
1420 * as appropriate to correctly scale the image.
1422 if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
1423 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1424 if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
1425 png_set_shift(png_ptr, &info_ptr->sig_bit);
1427 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
1430 /* Pack pixels into bytes */
1431 if ((transforms & PNG_TRANSFORM_PACKING) != 0)
1432 #ifdef PNG_WRITE_PACK_SUPPORTED
1433 png_set_packing(png_ptr);
1435 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
1438 /* Swap location of alpha bytes from ARGB to RGBA */
1439 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
1440 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1441 png_set_swap_alpha(png_ptr);
1443 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1446 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1447 * RGB, note that the code expects the input color type to be G or RGB; no
1450 if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
1451 PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
1453 #ifdef PNG_WRITE_FILLER_SUPPORTED
1454 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
1456 if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1457 png_app_error(png_ptr,
1458 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1460 /* Continue if ignored - this is the pre-1.6.10 behavior */
1461 png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
1464 else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
1465 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1467 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
1471 /* Flip BGR pixels to RGB */
1472 if ((transforms & PNG_TRANSFORM_BGR) != 0)
1473 #ifdef PNG_WRITE_BGR_SUPPORTED
1474 png_set_bgr(png_ptr);
1476 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
1479 /* Swap bytes of 16-bit files to most significant byte first */
1480 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
1481 #ifdef PNG_WRITE_SWAP_SUPPORTED
1482 png_set_swap(png_ptr);
1484 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1487 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1488 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
1489 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1490 png_set_packswap(png_ptr);
1492 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
1495 /* Invert the alpha channel from opacity to transparency */
1496 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
1497 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1498 png_set_invert_alpha(png_ptr);
1500 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1503 /* ----------------------- end of transformations ------------------- */
1505 /* Write the bits */
1506 png_write_image(png_ptr, info_ptr->row_pointers);
1508 /* It is REQUIRED to call this to finish writing the rest of the file */
1509 png_write_end(png_ptr, info_ptr);
1515 #ifdef PNG_WRITE_APNG_SUPPORTED
1517 png_write_frame_head(png_structp png_ptr, png_infop info_ptr,
1518 png_bytepp row_pointers, png_uint_32 width, png_uint_32 height,
1519 png_uint_32 x_offset, png_uint_32 y_offset,
1520 png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
1523 png_debug(1, "in png_write_frame_head");
1525 /* there is a chance this has been set after png_write_info was called,
1526 * so it would be set but not written. is there a way to be sure? */
1527 if (!(info_ptr->valid & PNG_INFO_acTL))
1528 png_error(png_ptr, "png_write_frame_head(): acTL not set");
1530 png_write_reset(png_ptr);
1532 png_write_reinit(png_ptr, info_ptr, width, height);
1534 if ( !(png_ptr->num_frames_written == 0 &&
1535 (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN) ) )
1536 png_write_fcTL(png_ptr, width, height, x_offset, y_offset,
1537 delay_num, delay_den, dispose_op, blend_op);
1539 PNG_UNUSED(row_pointers)
1543 png_write_frame_tail(png_structp png_ptr, png_infop info_ptr)
1545 png_debug(1, "in png_write_frame_tail");
1547 png_ptr->num_frames_written++;
1549 PNG_UNUSED(info_ptr)
1551 #endif /* PNG_WRITE_APNG_SUPPORTED */
1553 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1554 /* Initialize the write structure - general purpose utility. */
1556 png_image_write_init(png_imagep image)
1558 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
1559 png_safe_error, png_safe_warning);
1561 if (png_ptr != NULL)
1563 png_infop info_ptr = png_create_info_struct(png_ptr);
1565 if (info_ptr != NULL)
1567 png_controlp control = png_voidcast(png_controlp,
1568 png_malloc_warn(png_ptr, (sizeof *control)));
1570 if (control != NULL)
1572 memset(control, 0, (sizeof *control));
1574 control->png_ptr = png_ptr;
1575 control->info_ptr = info_ptr;
1576 control->for_write = 1;
1578 image->opaque = control;
1582 /* Error clean up */
1583 png_destroy_info_struct(png_ptr, &info_ptr);
1586 png_destroy_write_struct(&png_ptr, NULL);
1589 return png_image_error(image, "png_image_write_: out of memory");
1592 /* Arguments to png_image_write_main: */
1597 png_const_voidp buffer;
1598 png_int_32 row_stride;
1599 png_const_voidp colormap;
1600 int convert_to_8bit;
1601 /* Local variables: */
1602 png_const_voidp first_row;
1603 ptrdiff_t row_bytes;
1604 png_voidp local_row;
1605 /* Byte count for memory writing */
1607 png_alloc_size_t memory_bytes; /* not used for STDIO */
1608 png_alloc_size_t output_bytes; /* running total */
1609 } png_image_write_control;
1611 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1612 * do any necessary byte swapping. The component order is defined by the
1613 * png_image format value.
1616 png_write_image_16bit(png_voidp argument)
1618 png_image_write_control *display = png_voidcast(png_image_write_control*,
1620 png_imagep image = display->image;
1621 png_structrp png_ptr = image->opaque->png_ptr;
1623 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1624 display->first_row);
1625 png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
1626 png_uint_16p row_end;
1627 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1630 png_uint_32 y = image->height;
1632 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1634 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1635 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1638 ++input_row; /* To point to the first component */
1642 aindex = (int)channels;
1644 aindex = (int)channels;
1649 png_error(png_ptr, "png_write_image: internal call error");
1651 /* Work out the output row end and count over this, note that the increment
1652 * above to 'row' means that row_end can actually be beyond the end of the
1653 * row; this is correct.
1655 row_end = output_row + image->width * (channels+1);
1659 png_const_uint_16p in_ptr = input_row;
1660 png_uint_16p out_ptr = output_row;
1662 while (out_ptr < row_end)
1664 png_uint_16 alpha = in_ptr[aindex];
1665 png_uint_32 reciprocal = 0;
1668 out_ptr[aindex] = alpha;
1670 /* Calculate a reciprocal. The correct calculation is simply
1671 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1672 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1673 * is only initialized when required.
1675 if (alpha > 0 && alpha < 65535)
1676 reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
1679 do /* always at least one channel */
1681 png_uint_16 component = *in_ptr++;
1683 /* The following gives 65535 for an alpha of 0, which is fine,
1684 * otherwise if 0/0 is represented as some other value there is more
1685 * likely to be a discontinuity which will probably damage
1686 * compression when moving from a fully transparent area to a
1687 * nearly transparent one. (The assumption here is that opaque
1688 * areas tend not to be 0 intensity.)
1690 if (component >= alpha)
1693 /* component<alpha, so component/alpha is less than one and
1694 * component*reciprocal is less than 2^31.
1696 else if (component > 0 && alpha < 65535)
1698 png_uint_32 calc = component * reciprocal;
1699 calc += 16384; /* round to nearest */
1700 component = (png_uint_16)(calc >> 15);
1703 *out_ptr++ = component;
1707 /* Skip to next component (skip the intervening alpha channel) */
1712 png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
1713 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1719 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1720 * is present it must be removed from the components, the components are then
1721 * written in sRGB encoding. No components are added or removed.
1723 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1724 * calculation can be done to 15 bits of accuracy; however, the output needs to
1725 * be scaled in the range 0..255*65535, so include that scaling here.
1727 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1730 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
1731 png_uint_32 reciprocal/*from the above macro*/)
1733 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1734 * is represented as some other value there is more likely to be a
1735 * discontinuity which will probably damage compression when moving from a
1736 * fully transparent area to a nearly transparent one. (The assumption here
1737 * is that opaque areas tend not to be 0 intensity.)
1739 * There is a rounding problem here; if alpha is less than 128 it will end up
1740 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1741 * output change for this too.
1743 if (component >= alpha || alpha < 128)
1746 /* component<alpha, so component/alpha is less than one and
1747 * component*reciprocal is less than 2^31.
1749 else if (component > 0)
1751 /* The test is that alpha/257 (rounded) is less than 255, the first value
1752 * that becomes 255 is 65407.
1753 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1754 * be exact!) [Could also test reciprocal != 0]
1758 component *= reciprocal;
1759 component += 64; /* round to nearest */
1766 /* Convert the component to sRGB. */
1767 return (png_byte)PNG_sRGB_FROM_LINEAR(component);
1775 png_write_image_8bit(png_voidp argument)
1777 png_image_write_control *display = png_voidcast(png_image_write_control*,
1779 png_imagep image = display->image;
1780 png_structrp png_ptr = image->opaque->png_ptr;
1782 png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
1783 display->first_row);
1784 png_bytep output_row = png_voidcast(png_bytep, display->local_row);
1785 png_uint_32 y = image->height;
1786 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ?
1789 if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
1794 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1795 if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
1798 ++input_row; /* To point to the first component */
1804 aindex = (int)channels;
1806 /* Use row_end in place of a loop counter: */
1807 row_end = output_row + image->width * (channels+1);
1811 png_const_uint_16p in_ptr = input_row;
1812 png_bytep out_ptr = output_row;
1814 while (out_ptr < row_end)
1816 png_uint_16 alpha = in_ptr[aindex];
1817 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1818 png_uint_32 reciprocal = 0;
1821 /* Scale and write the alpha channel. */
1822 out_ptr[aindex] = alphabyte;
1824 if (alphabyte > 0 && alphabyte < 255)
1825 reciprocal = UNP_RECIPROCAL(alpha);
1828 do /* always at least one channel */
1829 *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
1832 /* Skip to next component (skip the intervening alpha channel) */
1835 } /* while out_ptr < row_end */
1837 png_write_row(png_ptr, png_voidcast(png_const_bytep,
1838 display->local_row));
1839 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1845 /* No alpha channel, so the row_end really is the end of the row and it
1846 * is sufficient to loop over the components one by one.
1848 png_bytep row_end = output_row + image->width * channels;
1852 png_const_uint_16p in_ptr = input_row;
1853 png_bytep out_ptr = output_row;
1855 while (out_ptr < row_end)
1857 png_uint_32 component = *in_ptr++;
1860 *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
1863 png_write_row(png_ptr, output_row);
1864 input_row += (png_uint_16)display->row_bytes/(sizeof (png_uint_16));
1872 png_image_set_PLTE(png_image_write_control *display)
1874 png_imagep image = display->image;
1875 const void *cmap = display->colormap;
1876 int entries = image->colormap_entries > 256 ? 256 :
1877 (int)image->colormap_entries;
1879 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1880 png_uint_32 format = image->format;
1881 unsigned int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
1883 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1884 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1885 int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
1886 (format & PNG_FORMAT_FLAG_ALPHA) != 0;
1891 # ifdef PNG_FORMAT_BGR_SUPPORTED
1892 int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
1898 png_color palette[256];
1901 memset(tRNS, 255, (sizeof tRNS));
1902 memset(palette, 0, (sizeof palette));
1904 for (i=num_trans=0; i<entries; ++i)
1906 /* This gets automatically converted to sRGB with reversal of the
1907 * pre-multiplication if the color-map has an alpha channel.
1909 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
1911 png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
1913 entry += (unsigned int)i * channels;
1915 if ((channels & 1) != 0) /* no alpha */
1917 if (channels >= 3) /* RGB */
1919 palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1921 palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1923 palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
1928 palette[i].blue = palette[i].red = palette[i].green =
1929 (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
1934 png_uint_16 alpha = entry[afirst ? 0 : channels-1];
1935 png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
1936 png_uint_32 reciprocal = 0;
1938 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1939 * this is designed to produce a value scaled to 255*65535 when
1940 * divided by 128 (i.e. asr 7).
1942 if (alphabyte > 0 && alphabyte < 255)
1943 reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
1945 tRNS[i] = alphabyte;
1946 if (alphabyte < 255)
1949 if (channels >= 3) /* RGB */
1951 palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
1953 palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
1955 palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
1960 palette[i].blue = palette[i].red = palette[i].green =
1961 png_unpremultiply(entry[afirst], alpha, reciprocal);
1965 else /* Color-map has sRGB values */
1967 png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
1969 entry += (unsigned int)i * channels;
1974 tRNS[i] = entry[afirst ? 0 : 3];
1979 palette[i].blue = entry[afirst + (2 ^ bgr)];
1980 palette[i].green = entry[afirst + 1];
1981 palette[i].red = entry[afirst + bgr];
1985 tRNS[i] = entry[1 ^ afirst];
1990 palette[i].blue = palette[i].red = palette[i].green =
2007 png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
2011 png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
2014 image->colormap_entries = (png_uint_32)entries;
2018 png_image_write_main(png_voidp argument)
2020 png_image_write_control *display = png_voidcast(png_image_write_control*,
2022 png_imagep image = display->image;
2023 png_structrp png_ptr = image->opaque->png_ptr;
2024 png_inforp info_ptr = image->opaque->info_ptr;
2025 png_uint_32 format = image->format;
2027 /* The following four ints are actually booleans */
2028 int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
2029 int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
2030 int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
2031 int write_16bit = linear && (display->convert_to_8bit == 0);
2033 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
2034 /* Make sure we error out on any bad situation */
2035 png_set_benign_errors(png_ptr, 0/*error*/);
2038 /* Default the 'row_stride' parameter if required, also check the row stride
2039 * and total image size to ensure that they are within the system limits.
2042 unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
2044 if (image->width <= 0x7fffffffU/channels) /* no overflow */
2047 png_uint_32 png_row_stride = image->width * channels;
2049 if (display->row_stride == 0)
2050 display->row_stride = (png_int_32)/*SAFE*/png_row_stride;
2052 if (display->row_stride < 0)
2053 check = (png_uint_32)(-display->row_stride);
2056 check = (png_uint_32)display->row_stride;
2058 if (check >= png_row_stride)
2060 /* Now check for overflow of the image buffer calculation; this
2061 * limits the whole image size to 32 bits for API compatibility with
2062 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
2064 if (image->height > 0xffffffffU/png_row_stride)
2065 png_error(image->opaque->png_ptr, "memory image too large");
2069 png_error(image->opaque->png_ptr, "supplied row stride too small");
2073 png_error(image->opaque->png_ptr, "image row stride too large");
2076 /* Set the required transforms then write the rows in the correct order. */
2077 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
2079 if (display->colormap != NULL && image->colormap_entries > 0)
2081 png_uint_32 entries = image->colormap_entries;
2083 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2084 entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
2085 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
2086 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2088 png_image_set_PLTE(display);
2092 png_error(image->opaque->png_ptr,
2093 "no color-map for color-mapped image");
2097 png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
2098 write_16bit ? 16 : 8,
2099 ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
2100 ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
2101 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
2103 /* Counter-intuitively the data transformations must be called *after*
2104 * png_write_info, not before as in the read code, but the 'set' functions
2105 * must still be called before. Just set the color space information, never
2106 * write an interlaced image.
2109 if (write_16bit != 0)
2111 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2112 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
2114 if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2115 png_set_cHRM_fixed(png_ptr, info_ptr,
2117 /* white */ 31270, 32900,
2118 /* red */ 64000, 33000,
2119 /* green */ 30000, 60000,
2120 /* blue */ 15000, 6000
2124 else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
2125 png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
2127 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2128 * space must still be gamma encoded.
2131 png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
2133 /* Write the file header. */
2134 png_write_info(png_ptr, info_ptr);
2136 /* Now set up the data transformations (*after* the header is written),
2137 * remove the handled transformations from the 'format' flags for checking.
2139 * First check for a little endian system if writing 16-bit files.
2141 if (write_16bit != 0)
2143 png_uint_16 le = 0x0001;
2145 if ((*(png_const_bytep) & le) != 0)
2146 png_set_swap(png_ptr);
2149 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2150 if ((format & PNG_FORMAT_FLAG_BGR) != 0)
2152 if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
2153 png_set_bgr(png_ptr);
2154 format &= ~PNG_FORMAT_FLAG_BGR;
2158 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2159 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
2161 if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
2162 png_set_swap_alpha(png_ptr);
2163 format &= ~PNG_FORMAT_FLAG_AFIRST;
2167 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2168 * above, but the application data is still byte packed.
2170 if (colormap != 0 && image->colormap_entries <= 16)
2171 png_set_packing(png_ptr);
2173 /* That should have handled all (both) the transforms. */
2174 if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
2175 PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
2176 png_error(png_ptr, "png_write_image: unsupported transformation");
2179 png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
2180 ptrdiff_t row_bytes = display->row_stride;
2183 row_bytes *= (sizeof (png_uint_16));
2186 row += (image->height-1) * (-row_bytes);
2188 display->first_row = row;
2189 display->row_bytes = row_bytes;
2192 /* Apply 'fast' options if the flag is set. */
2193 if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
2195 png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
2196 /* NOTE: determined by experiment using pngstest, this reflects some
2197 * balance between the time to write the image once and the time to read
2198 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2199 * total (user) time on a heavily loaded system.
2201 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2202 png_set_compression_level(png_ptr, 3);
2206 /* Check for the cases that currently require a pre-transform on the row
2207 * before it is written. This only applies when the input is 16-bit and
2208 * either there is an alpha channel or it is converted to 8-bit.
2210 if ((linear != 0 && alpha != 0 ) ||
2211 (colormap == 0 && display->convert_to_8bit != 0))
2213 png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
2214 png_get_rowbytes(png_ptr, info_ptr)));
2217 display->local_row = row;
2218 if (write_16bit != 0)
2219 result = png_safe_execute(image, png_write_image_16bit, display);
2221 result = png_safe_execute(image, png_write_image_8bit, display);
2222 display->local_row = NULL;
2224 png_free(png_ptr, row);
2226 /* Skip the 'write_end' on error: */
2231 /* Otherwise this is the case where the input is in a format currently
2232 * supported by the rest of the libpng write code; call it directly.
2236 png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
2237 ptrdiff_t row_bytes = display->row_bytes;
2238 png_uint_32 y = image->height;
2242 png_write_row(png_ptr, row);
2247 png_write_end(png_ptr, info_ptr);
2252 static void (PNGCBAPI
2253 image_memory_write)(png_structp png_ptr, png_bytep/*const*/ data, size_t size)
2255 png_image_write_control *display = png_voidcast(png_image_write_control*,
2256 png_ptr->io_ptr/*backdoor: png_get_io_ptr(png_ptr)*/);
2257 png_alloc_size_t ob = display->output_bytes;
2259 /* Check for overflow; this should never happen: */
2260 if (size <= ((png_alloc_size_t)-1) - ob)
2262 /* I don't think libpng ever does this, but just in case: */
2265 if (display->memory_bytes >= ob+size) /* writing */
2266 memcpy(display->memory+ob, data, size);
2268 /* Always update the size: */
2269 display->output_bytes = ob+size;
2274 png_error(png_ptr, "png_image_write_to_memory: PNG too big");
2277 static void (PNGCBAPI
2278 image_memory_flush)(png_structp png_ptr)
2284 png_image_write_memory(png_voidp argument)
2286 png_image_write_control *display = png_voidcast(png_image_write_control*,
2289 /* The rest of the memory-specific init and write_main in an error protected
2290 * environment. This case needs to use callbacks for the write operations
2291 * since libpng has no built in support for writing to memory.
2293 png_set_write_fn(display->image->opaque->png_ptr, display/*io_ptr*/,
2294 image_memory_write, image_memory_flush);
2296 return png_image_write_main(display);
2300 png_image_write_to_memory(png_imagep image, void *memory,
2301 png_alloc_size_t * PNG_RESTRICT memory_bytes, int convert_to_8bit,
2302 const void *buffer, png_int_32 row_stride, const void *colormap)
2304 /* Write the image to the given buffer, or count the bytes if it is NULL */
2305 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2307 if (memory_bytes != NULL && buffer != NULL)
2309 /* This is to give the caller an easier error detection in the NULL
2310 * case and guard against uninitialized variable problems:
2315 if (png_image_write_init(image) != 0)
2317 png_image_write_control display;
2320 memset(&display, 0, (sizeof display));
2321 display.image = image;
2322 display.buffer = buffer;
2323 display.row_stride = row_stride;
2324 display.colormap = colormap;
2325 display.convert_to_8bit = convert_to_8bit;
2326 display.memory = png_voidcast(png_bytep, memory);
2327 display.memory_bytes = *memory_bytes;
2328 display.output_bytes = 0;
2330 result = png_safe_execute(image, png_image_write_memory, &display);
2331 png_image_free(image);
2333 /* write_memory returns true even if we ran out of buffer. */
2336 /* On out-of-buffer this function returns '0' but still updates
2339 if (memory != NULL && display.output_bytes > *memory_bytes)
2342 *memory_bytes = display.output_bytes;
2353 return png_image_error(image,
2354 "png_image_write_to_memory: invalid argument");
2357 else if (image != NULL)
2358 return png_image_error(image,
2359 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2365 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2367 png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
2368 const void *buffer, png_int_32 row_stride, const void *colormap)
2370 /* Write the image to the given (FILE*). */
2371 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2373 if (file != NULL && buffer != NULL)
2375 if (png_image_write_init(image) != 0)
2377 png_image_write_control display;
2380 /* This is slightly evil, but png_init_io doesn't do anything other
2381 * than this and we haven't changed the standard IO functions so
2382 * this saves a 'safe' function.
2384 image->opaque->png_ptr->io_ptr = file;
2386 memset(&display, 0, (sizeof display));
2387 display.image = image;
2388 display.buffer = buffer;
2389 display.row_stride = row_stride;
2390 display.colormap = colormap;
2391 display.convert_to_8bit = convert_to_8bit;
2393 result = png_safe_execute(image, png_image_write_main, &display);
2394 png_image_free(image);
2403 return png_image_error(image,
2404 "png_image_write_to_stdio: invalid argument");
2407 else if (image != NULL)
2408 return png_image_error(image,
2409 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2416 png_image_write_to_file(png_imagep image, const char *file_name,
2417 int convert_to_8bit, const void *buffer, png_int_32 row_stride,
2418 const void *colormap)
2420 /* Write the image to the named file. */
2421 if (image != NULL && image->version == PNG_IMAGE_VERSION)
2423 if (file_name != NULL && buffer != NULL)
2425 FILE *fp = fopen(file_name, "wb");
2429 if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
2430 row_stride, colormap) != 0)
2432 int error; /* from fflush/fclose */
2434 /* Make sure the file is flushed correctly. */
2435 if (fflush(fp) == 0 && ferror(fp) == 0)
2437 if (fclose(fp) == 0)
2440 error = errno; /* from fclose */
2445 error = errno; /* from fflush or ferror */
2449 (void)remove(file_name);
2450 /* The image has already been cleaned up; this is just used to
2451 * set the error (because the original write succeeded).
2453 return png_image_error(image, strerror(error));
2458 /* Clean up: just the opened file. */
2460 (void)remove(file_name);
2466 return png_image_error(image, strerror(errno));
2470 return png_image_error(image,
2471 "png_image_write_to_file: invalid argument");
2474 else if (image != NULL)
2475 return png_image_error(image,
2476 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2481 #endif /* SIMPLIFIED_WRITE_STDIO */
2482 #endif /* SIMPLIFIED_WRITE */