2 /* pngwrite.c - general routines to write a PNG file
4 * Last changed in libpng 1.2.27 [April 29, 2008]
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2008 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
11 /* get internal access to png.h */
14 #ifdef PNG_WRITE_SUPPORTED
16 /* Writes all the PNG information. This is the suggested way to use the
17 * library. If you have a new chunk to add, make a function to write it,
18 * and put it in the correct location here. If you want the chunk written
19 * after the image data, put it in png_write_end(). I strongly encourage
20 * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
21 * the chunk, as that will keep the code from breaking if you want to just
22 * write a plain PNG file. If you have long comments, I suggest writing
23 * them in png_write_end(), and compressing them.
26 png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
28 png_debug(1, "in png_write_info_before_PLTE\n");
29 if (png_ptr == NULL || info_ptr == NULL)
31 if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
33 png_write_sig(png_ptr); /* write PNG signature */
34 #if defined(PNG_MNG_FEATURES_SUPPORTED)
35 if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
37 png_warning(png_ptr,"MNG features are not allowed in a PNG datastream");
38 png_ptr->mng_features_permitted=0;
41 /* write IHDR information. */
42 png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
43 info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
44 info_ptr->filter_type,
45 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
46 info_ptr->interlace_type);
50 /* the rest of these check to see if the valid field has the appropriate
51 flag set, and if it does, writes the chunk. */
52 #if defined(PNG_WRITE_gAMA_SUPPORTED)
53 if (info_ptr->valid & PNG_INFO_gAMA)
55 # ifdef PNG_FLOATING_POINT_SUPPORTED
56 png_write_gAMA(png_ptr, info_ptr->gamma);
58 #ifdef PNG_FIXED_POINT_SUPPORTED
59 png_write_gAMA_fixed(png_ptr, info_ptr->int_gamma);
64 #if defined(PNG_WRITE_sRGB_SUPPORTED)
65 if (info_ptr->valid & PNG_INFO_sRGB)
66 png_write_sRGB(png_ptr, (int)info_ptr->srgb_intent);
68 #if defined(PNG_WRITE_iCCP_SUPPORTED)
69 if (info_ptr->valid & PNG_INFO_iCCP)
70 png_write_iCCP(png_ptr, info_ptr->iccp_name, PNG_COMPRESSION_TYPE_BASE,
71 info_ptr->iccp_profile, (int)info_ptr->iccp_proflen);
73 #if defined(PNG_WRITE_sBIT_SUPPORTED)
74 if (info_ptr->valid & PNG_INFO_sBIT)
75 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
77 #if defined(PNG_WRITE_cHRM_SUPPORTED)
78 if (info_ptr->valid & PNG_INFO_cHRM)
80 #ifdef PNG_FLOATING_POINT_SUPPORTED
81 png_write_cHRM(png_ptr,
82 info_ptr->x_white, info_ptr->y_white,
83 info_ptr->x_red, info_ptr->y_red,
84 info_ptr->x_green, info_ptr->y_green,
85 info_ptr->x_blue, info_ptr->y_blue);
87 # ifdef PNG_FIXED_POINT_SUPPORTED
88 png_write_cHRM_fixed(png_ptr,
89 info_ptr->int_x_white, info_ptr->int_y_white,
90 info_ptr->int_x_red, info_ptr->int_y_red,
91 info_ptr->int_x_green, info_ptr->int_y_green,
92 info_ptr->int_x_blue, info_ptr->int_y_blue);
97 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
98 if (info_ptr->unknown_chunks_num)
100 png_unknown_chunk *up;
102 png_debug(5, "writing extra chunks\n");
104 for (up = info_ptr->unknown_chunks;
105 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
108 int keep=png_handle_as_unknown(png_ptr, up->name);
109 if (keep != PNG_HANDLE_CHUNK_NEVER &&
110 up->location && !(up->location & PNG_HAVE_PLTE) &&
111 !(up->location & PNG_HAVE_IDAT) &&
112 ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
113 (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
116 png_warning(png_ptr, "Writing zero-length unknown chunk");
117 png_write_chunk(png_ptr, up->name, up->data, up->size);
122 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
127 png_write_info(png_structp png_ptr, png_infop info_ptr)
129 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
133 png_debug(1, "in png_write_info\n");
135 if (png_ptr == NULL || info_ptr == NULL)
138 png_write_info_before_PLTE(png_ptr, info_ptr);
140 if (info_ptr->valid & PNG_INFO_PLTE)
141 png_write_PLTE(png_ptr, info_ptr->palette,
142 (png_uint_32)info_ptr->num_palette);
143 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
144 png_error(png_ptr, "Valid palette required for paletted images");
146 #if defined(PNG_WRITE_tRNS_SUPPORTED)
147 if (info_ptr->valid & PNG_INFO_tRNS)
149 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
150 /* invert the alpha channel (in tRNS) */
151 if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
152 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
155 for (j=0; j<(int)info_ptr->num_trans; j++)
156 info_ptr->trans[j] = (png_byte)(255 - info_ptr->trans[j]);
159 png_write_tRNS(png_ptr, info_ptr->trans, &(info_ptr->trans_values),
160 info_ptr->num_trans, info_ptr->color_type);
163 #if defined(PNG_WRITE_bKGD_SUPPORTED)
164 if (info_ptr->valid & PNG_INFO_bKGD)
165 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
167 #if defined(PNG_WRITE_hIST_SUPPORTED)
168 if (info_ptr->valid & PNG_INFO_hIST)
169 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
171 #if defined(PNG_WRITE_oFFs_SUPPORTED)
172 if (info_ptr->valid & PNG_INFO_oFFs)
173 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
174 info_ptr->offset_unit_type);
176 #if defined(PNG_WRITE_pCAL_SUPPORTED)
177 if (info_ptr->valid & PNG_INFO_pCAL)
178 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
179 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
180 info_ptr->pcal_units, info_ptr->pcal_params);
182 #if defined(PNG_WRITE_sCAL_SUPPORTED)
183 if (info_ptr->valid & PNG_INFO_sCAL)
184 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
185 png_write_sCAL(png_ptr, (int)info_ptr->scal_unit,
186 info_ptr->scal_pixel_width, info_ptr->scal_pixel_height);
188 #ifdef PNG_FIXED_POINT_SUPPORTED
189 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
190 info_ptr->scal_s_width, info_ptr->scal_s_height);
193 "png_write_sCAL not supported; sCAL chunk not written.");
197 #if defined(PNG_WRITE_pHYs_SUPPORTED)
198 if (info_ptr->valid & PNG_INFO_pHYs)
199 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
200 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
202 #if defined(PNG_WRITE_tIME_SUPPORTED)
203 if (info_ptr->valid & PNG_INFO_tIME)
205 png_write_tIME(png_ptr, &(info_ptr->mod_time));
206 png_ptr->mode |= PNG_WROTE_tIME;
209 #if defined(PNG_WRITE_sPLT_SUPPORTED)
210 if (info_ptr->valid & PNG_INFO_sPLT)
211 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
212 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
214 #if defined(PNG_WRITE_TEXT_SUPPORTED)
215 /* Check to see if we need to write text chunks */
216 for (i = 0; i < info_ptr->num_text; i++)
218 png_debug2(2, "Writing header text chunk %d, type %d\n", i,
219 info_ptr->text[i].compression);
220 /* an internationalized chunk? */
221 if (info_ptr->text[i].compression > 0)
223 #if defined(PNG_WRITE_iTXt_SUPPORTED)
224 /* write international chunk */
225 png_write_iTXt(png_ptr,
226 info_ptr->text[i].compression,
227 info_ptr->text[i].key,
228 info_ptr->text[i].lang,
229 info_ptr->text[i].lang_key,
230 info_ptr->text[i].text);
232 png_warning(png_ptr, "Unable to write international text");
234 /* Mark this chunk as written */
235 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
237 /* If we want a compressed text chunk */
238 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
240 #if defined(PNG_WRITE_zTXt_SUPPORTED)
241 /* write compressed chunk */
242 png_write_zTXt(png_ptr, info_ptr->text[i].key,
243 info_ptr->text[i].text, 0,
244 info_ptr->text[i].compression);
246 png_warning(png_ptr, "Unable to write compressed text");
248 /* Mark this chunk as written */
249 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
251 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
253 #if defined(PNG_WRITE_tEXt_SUPPORTED)
254 /* write uncompressed chunk */
255 png_write_tEXt(png_ptr, info_ptr->text[i].key,
256 info_ptr->text[i].text,
259 png_warning(png_ptr, "Unable to write uncompressed text");
261 /* Mark this chunk as written */
262 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
266 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
267 if (info_ptr->unknown_chunks_num)
269 png_unknown_chunk *up;
271 png_debug(5, "writing extra chunks\n");
273 for (up = info_ptr->unknown_chunks;
274 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
277 int keep=png_handle_as_unknown(png_ptr, up->name);
278 if (keep != PNG_HANDLE_CHUNK_NEVER &&
279 up->location && (up->location & PNG_HAVE_PLTE) &&
280 !(up->location & PNG_HAVE_IDAT) &&
281 ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
282 (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
284 png_write_chunk(png_ptr, up->name, up->data, up->size);
291 /* Writes the end of the PNG file. If you don't want to write comments or
292 * time information, you can pass NULL for info. If you already wrote these
293 * in png_write_info(), do not write them again here. If you have long
294 * comments, I suggest writing them here, and compressing them.
297 png_write_end(png_structp png_ptr, png_infop info_ptr)
299 png_debug(1, "in png_write_end\n");
302 if (!(png_ptr->mode & PNG_HAVE_IDAT))
303 png_error(png_ptr, "No IDATs written into file");
305 /* see if user wants us to write information chunks */
306 if (info_ptr != NULL)
308 #if defined(PNG_WRITE_TEXT_SUPPORTED)
309 int i; /* local index variable */
311 #if defined(PNG_WRITE_tIME_SUPPORTED)
312 /* check to see if user has supplied a time chunk */
313 if ((info_ptr->valid & PNG_INFO_tIME) &&
314 !(png_ptr->mode & PNG_WROTE_tIME))
315 png_write_tIME(png_ptr, &(info_ptr->mod_time));
317 #if defined(PNG_WRITE_TEXT_SUPPORTED)
318 /* loop through comment chunks */
319 for (i = 0; i < info_ptr->num_text; i++)
321 png_debug2(2, "Writing trailer text chunk %d, type %d\n", i,
322 info_ptr->text[i].compression);
323 /* an internationalized chunk? */
324 if (info_ptr->text[i].compression > 0)
326 #if defined(PNG_WRITE_iTXt_SUPPORTED)
327 /* write international chunk */
328 png_write_iTXt(png_ptr,
329 info_ptr->text[i].compression,
330 info_ptr->text[i].key,
331 info_ptr->text[i].lang,
332 info_ptr->text[i].lang_key,
333 info_ptr->text[i].text);
335 png_warning(png_ptr, "Unable to write international text");
337 /* Mark this chunk as written */
338 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
340 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
342 #if defined(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, 0,
346 info_ptr->text[i].compression);
348 png_warning(png_ptr, "Unable to write compressed text");
350 /* Mark this chunk as written */
351 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
353 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
355 #if defined(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, 0);
360 png_warning(png_ptr, "Unable to write uncompressed text");
363 /* Mark this chunk as written */
364 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
368 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
369 if (info_ptr->unknown_chunks_num)
371 png_unknown_chunk *up;
373 png_debug(5, "writing extra chunks\n");
375 for (up = info_ptr->unknown_chunks;
376 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
379 int keep=png_handle_as_unknown(png_ptr, up->name);
380 if (keep != PNG_HANDLE_CHUNK_NEVER &&
381 up->location && (up->location & PNG_AFTER_IDAT) &&
382 ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
383 (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
385 png_write_chunk(png_ptr, up->name, up->data, up->size);
392 png_ptr->mode |= PNG_AFTER_IDAT;
394 /* write end of PNG file */
395 png_write_IEND(png_ptr);
398 #if defined(PNG_WRITE_tIME_SUPPORTED)
399 #if !defined(_WIN32_WCE)
400 /* "time.h" functions are not supported on WindowsCE */
402 png_convert_from_struct_tm(png_timep ptime, struct tm FAR * ttime)
404 png_debug(1, "in png_convert_from_struct_tm\n");
405 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
406 ptime->month = (png_byte)(ttime->tm_mon + 1);
407 ptime->day = (png_byte)ttime->tm_mday;
408 ptime->hour = (png_byte)ttime->tm_hour;
409 ptime->minute = (png_byte)ttime->tm_min;
410 ptime->second = (png_byte)ttime->tm_sec;
414 png_convert_from_time_t(png_timep ptime, time_t ttime)
418 png_debug(1, "in png_convert_from_time_t\n");
419 tbuf = gmtime(&ttime);
420 png_convert_from_struct_tm(ptime, tbuf);
425 /* Initialize png_ptr structure, and allocate any memory needed */
427 png_create_write_struct(png_const_charp user_png_ver, png_voidp error_ptr,
428 png_error_ptr error_fn, png_error_ptr warn_fn)
430 #ifdef PNG_USER_MEM_SUPPORTED
431 return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
432 warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
435 /* Alternate initialize png_ptr structure, and allocate any memory needed */
437 png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
438 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
439 png_malloc_ptr malloc_fn, png_free_ptr free_fn)
441 #endif /* PNG_USER_MEM_SUPPORTED */
443 #ifdef PNG_SETJMP_SUPPORTED
444 #ifdef USE_FAR_KEYWORD
449 png_debug(1, "in png_create_write_struct\n");
450 #ifdef PNG_USER_MEM_SUPPORTED
451 png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
452 (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
454 png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
455 #endif /* PNG_USER_MEM_SUPPORTED */
459 /* added at libpng-1.2.6 */
460 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
461 png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
462 png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
465 #ifdef PNG_SETJMP_SUPPORTED
466 #ifdef USE_FAR_KEYWORD
469 if (setjmp(png_ptr->jmpbuf))
472 png_free(png_ptr, png_ptr->zbuf);
474 png_destroy_struct(png_ptr);
477 #ifdef USE_FAR_KEYWORD
478 png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
482 #ifdef PNG_USER_MEM_SUPPORTED
483 png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
484 #endif /* PNG_USER_MEM_SUPPORTED */
485 png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
492 if(user_png_ver[i] != png_libpng_ver[i])
493 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
494 } while (png_libpng_ver[i++]);
497 if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
499 /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
500 * we must recompile any applications that use any older library version.
501 * For versions after libpng 1.0, we will be compatible, so we need
502 * only check the first digit.
504 if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
505 (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
506 (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
508 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
512 png_snprintf(msg, 80,
513 "Application was compiled with png.h from libpng-%.20s",
515 png_warning(png_ptr, msg);
517 png_snprintf(msg, 80,
518 "Application is running with png.c from libpng-%.20s",
520 png_warning(png_ptr, msg);
522 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
526 "Incompatible libpng version in application and library");
530 /* initialize zbuf - compression buffer */
531 png_ptr->zbuf_size = PNG_ZBUF_SIZE;
532 png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
533 (png_uint_32)png_ptr->zbuf_size);
535 png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,
538 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
539 png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
540 1, png_doublep_NULL, png_doublep_NULL);
543 #ifdef PNG_SETJMP_SUPPORTED
544 /* Applications that neglect to set up their own setjmp() and then encounter
545 a png_error() will longjmp here. Since the jmpbuf is then meaningless we
546 abort instead of returning. */
547 #ifdef USE_FAR_KEYWORD
550 png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
552 if (setjmp(png_ptr->jmpbuf))
559 /* Initialize png_ptr structure, and allocate any memory needed */
560 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
562 #undef png_write_init
564 png_write_init(png_structp png_ptr)
566 /* We only come here via pre-1.0.7-compiled applications */
567 png_write_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
571 png_write_init_2(png_structp png_ptr, png_const_charp user_png_ver,
572 png_size_t png_struct_size, png_size_t png_info_size)
574 /* We only come here via pre-1.0.12-compiled applications */
575 if(png_ptr == NULL) return;
576 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
577 if(png_sizeof(png_struct) > png_struct_size ||
578 png_sizeof(png_info) > png_info_size)
581 png_ptr->warning_fn=NULL;
584 png_snprintf(msg, 80,
585 "Application was compiled with png.h from libpng-%.20s",
587 png_warning(png_ptr, msg);
589 png_snprintf(msg, 80,
590 "Application is running with png.c from libpng-%.20s",
592 png_warning(png_ptr, msg);
595 if(png_sizeof(png_struct) > png_struct_size)
597 png_ptr->error_fn=NULL;
598 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
602 "The png struct allocated by the application for writing is too small.");
604 if(png_sizeof(png_info) > png_info_size)
606 png_ptr->error_fn=NULL;
607 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
611 "The info struct allocated by the application for writing is too small.");
613 png_write_init_3(&png_ptr, user_png_ver, png_struct_size);
615 #endif /* PNG_1_0_X || PNG_1_2_X */
619 png_write_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
620 png_size_t png_struct_size)
622 png_structp png_ptr=*ptr_ptr;
623 #ifdef PNG_SETJMP_SUPPORTED
624 jmp_buf tmp_jmp; /* to save current jump buffer */
634 if (user_png_ver[i] != png_libpng_ver[i])
636 #ifdef PNG_LEGACY_SUPPORTED
637 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
639 png_ptr->warning_fn=NULL;
641 "Application uses deprecated png_write_init() and should be recompiled.");
645 } while (png_libpng_ver[i++]);
647 png_debug(1, "in png_write_init_3\n");
649 #ifdef PNG_SETJMP_SUPPORTED
650 /* save jump buffer and error functions */
651 png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
654 if (png_sizeof(png_struct) > png_struct_size)
656 png_destroy_struct(png_ptr);
657 png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
661 /* reset all variables to 0 */
662 png_memset(png_ptr, 0, png_sizeof (png_struct));
664 /* added at libpng-1.2.6 */
665 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
666 png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
667 png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
670 #ifdef PNG_SETJMP_SUPPORTED
671 /* restore jump buffer */
672 png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
675 png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,
678 /* initialize zbuf - compression buffer */
679 png_ptr->zbuf_size = PNG_ZBUF_SIZE;
680 png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
681 (png_uint_32)png_ptr->zbuf_size);
683 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
684 png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
685 1, png_doublep_NULL, png_doublep_NULL);
689 /* Write a few rows of image data. If the image is interlaced,
690 * either you will have to write the 7 sub images, or, if you
691 * have called png_set_interlace_handling(), you will have to
692 * "write" the image seven times.
695 png_write_rows(png_structp png_ptr, png_bytepp row,
696 png_uint_32 num_rows)
698 png_uint_32 i; /* row counter */
699 png_bytepp rp; /* row pointer */
701 png_debug(1, "in png_write_rows\n");
706 /* loop through the rows */
707 for (i = 0, rp = row; i < num_rows; i++, rp++)
709 png_write_row(png_ptr, *rp);
713 /* Write the image. You only need to call this function once, even
714 * if you are writing an interlaced image.
717 png_write_image(png_structp png_ptr, png_bytepp image)
719 png_uint_32 i; /* row index */
720 int pass, num_pass; /* pass variables */
721 png_bytepp rp; /* points to current row */
726 png_debug(1, "in png_write_image\n");
727 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
728 /* intialize interlace handling. If image is not interlaced,
729 this will set pass to 1 */
730 num_pass = png_set_interlace_handling(png_ptr);
734 /* loop through passes */
735 for (pass = 0; pass < num_pass; pass++)
737 /* loop through image */
738 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
740 png_write_row(png_ptr, *rp);
745 /* called by user to write a row of image data */
747 png_write_row(png_structp png_ptr, png_bytep row)
751 png_debug2(1, "in png_write_row (row %ld, pass %d)\n",
752 png_ptr->row_number, png_ptr->pass);
754 /* initialize transformations and other stuff if first time */
755 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
757 /* make sure we wrote the header info */
758 if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
760 "png_write_info was never called before png_write_row.");
762 /* check for transforms that have been set but were defined out */
763 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
764 if (png_ptr->transformations & PNG_INVERT_MONO)
765 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined.");
767 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
768 if (png_ptr->transformations & PNG_FILLER)
769 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined.");
771 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && defined(PNG_READ_PACKSWAP_SUPPORTED)
772 if (png_ptr->transformations & PNG_PACKSWAP)
773 png_warning(png_ptr, "PNG_WRITE_PACKSWAP_SUPPORTED is not defined.");
775 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
776 if (png_ptr->transformations & PNG_PACK)
777 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined.");
779 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
780 if (png_ptr->transformations & PNG_SHIFT)
781 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined.");
783 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
784 if (png_ptr->transformations & PNG_BGR)
785 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined.");
787 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
788 if (png_ptr->transformations & PNG_SWAP_BYTES)
789 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined.");
792 png_write_start_row(png_ptr);
795 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
796 /* if interlaced and not interested in row, return */
797 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
799 switch (png_ptr->pass)
802 if (png_ptr->row_number & 0x07)
804 png_write_finish_row(png_ptr);
809 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
811 png_write_finish_row(png_ptr);
816 if ((png_ptr->row_number & 0x07) != 4)
818 png_write_finish_row(png_ptr);
823 if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
825 png_write_finish_row(png_ptr);
830 if ((png_ptr->row_number & 0x03) != 2)
832 png_write_finish_row(png_ptr);
837 if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
839 png_write_finish_row(png_ptr);
844 if (!(png_ptr->row_number & 0x01))
846 png_write_finish_row(png_ptr);
854 /* set up row info for transformations */
855 png_ptr->row_info.color_type = png_ptr->color_type;
856 png_ptr->row_info.width = png_ptr->usr_width;
857 png_ptr->row_info.channels = png_ptr->usr_channels;
858 png_ptr->row_info.bit_depth = png_ptr->usr_bit_depth;
859 png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
860 png_ptr->row_info.channels);
862 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
863 png_ptr->row_info.width);
865 png_debug1(3, "row_info->color_type = %d\n", png_ptr->row_info.color_type);
866 png_debug1(3, "row_info->width = %lu\n", png_ptr->row_info.width);
867 png_debug1(3, "row_info->channels = %d\n", png_ptr->row_info.channels);
868 png_debug1(3, "row_info->bit_depth = %d\n", png_ptr->row_info.bit_depth);
869 png_debug1(3, "row_info->pixel_depth = %d\n", png_ptr->row_info.pixel_depth);
870 png_debug1(3, "row_info->rowbytes = %lu\n", png_ptr->row_info.rowbytes);
872 /* Copy user's row into buffer, leaving room for filter byte. */
873 png_memcpy_check(png_ptr, png_ptr->row_buf + 1, row,
874 png_ptr->row_info.rowbytes);
876 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
877 /* handle interlacing */
878 if (png_ptr->interlaced && png_ptr->pass < 6 &&
879 (png_ptr->transformations & PNG_INTERLACE))
881 png_do_write_interlace(&(png_ptr->row_info),
882 png_ptr->row_buf + 1, png_ptr->pass);
883 /* this should always get caught above, but still ... */
884 if (!(png_ptr->row_info.width))
886 png_write_finish_row(png_ptr);
892 /* handle other transformations */
893 if (png_ptr->transformations)
894 png_do_write_transformations(png_ptr);
896 #if defined(PNG_MNG_FEATURES_SUPPORTED)
897 /* Write filter_method 64 (intrapixel differencing) only if
898 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
899 * 2. Libpng did not write a PNG signature (this filter_method is only
900 * used in PNG datastreams that are embedded in MNG datastreams) and
901 * 3. The application called png_permit_mng_features with a mask that
902 * included PNG_FLAG_MNG_FILTER_64 and
903 * 4. The filter_method is 64 and
904 * 5. The color_type is RGB or RGBA
906 if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
907 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
909 /* Intrapixel differencing */
910 png_do_write_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
914 /* Find a filter if necessary, filter the row and write it out. */
915 png_write_find_filter(png_ptr, &(png_ptr->row_info));
917 if (png_ptr->write_row_fn != NULL)
918 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
921 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
922 /* Set the automatic flush interval or 0 to turn flushing off */
924 png_set_flush(png_structp png_ptr, int nrows)
926 png_debug(1, "in png_set_flush\n");
929 png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
932 /* flush the current output buffers now */
934 png_write_flush(png_structp png_ptr)
938 png_debug(1, "in png_write_flush\n");
941 /* We have already written out all of the data */
942 if (png_ptr->row_number >= png_ptr->num_rows)
949 /* compress the data */
950 ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);
953 /* check for compression errors */
956 if (png_ptr->zstream.msg != NULL)
957 png_error(png_ptr, png_ptr->zstream.msg);
959 png_error(png_ptr, "zlib error");
962 if (!(png_ptr->zstream.avail_out))
964 /* write the IDAT and reset the zlib output buffer */
965 png_write_IDAT(png_ptr, png_ptr->zbuf,
967 png_ptr->zstream.next_out = png_ptr->zbuf;
968 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
971 } while(wrote_IDAT == 1);
973 /* If there is any data left to be output, write it into a new IDAT */
974 if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)
976 /* write the IDAT and reset the zlib output buffer */
977 png_write_IDAT(png_ptr, png_ptr->zbuf,
978 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
979 png_ptr->zstream.next_out = png_ptr->zbuf;
980 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
982 png_ptr->flush_rows = 0;
985 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
987 /* free all memory used by the write */
989 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
991 png_structp png_ptr = NULL;
992 png_infop info_ptr = NULL;
993 #ifdef PNG_USER_MEM_SUPPORTED
994 png_free_ptr free_fn = NULL;
995 png_voidp mem_ptr = NULL;
998 png_debug(1, "in png_destroy_write_struct\n");
999 if (png_ptr_ptr != NULL)
1001 png_ptr = *png_ptr_ptr;
1002 #ifdef PNG_USER_MEM_SUPPORTED
1003 free_fn = png_ptr->free_fn;
1004 mem_ptr = png_ptr->mem_ptr;
1008 #ifdef PNG_USER_MEM_SUPPORTED
1009 if (png_ptr != NULL)
1011 free_fn = png_ptr->free_fn;
1012 mem_ptr = png_ptr->mem_ptr;
1016 if (info_ptr_ptr != NULL)
1017 info_ptr = *info_ptr_ptr;
1019 if (info_ptr != NULL)
1021 if (png_ptr != NULL)
1023 png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
1025 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
1026 if (png_ptr->num_chunk_list)
1028 png_free(png_ptr, png_ptr->chunk_list);
1029 png_ptr->chunk_list=NULL;
1030 png_ptr->num_chunk_list=0;
1035 #ifdef PNG_USER_MEM_SUPPORTED
1036 png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
1037 (png_voidp)mem_ptr);
1039 png_destroy_struct((png_voidp)info_ptr);
1041 *info_ptr_ptr = NULL;
1044 if (png_ptr != NULL)
1046 png_write_destroy(png_ptr);
1047 #ifdef PNG_USER_MEM_SUPPORTED
1048 png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
1049 (png_voidp)mem_ptr);
1051 png_destroy_struct((png_voidp)png_ptr);
1053 *png_ptr_ptr = NULL;
1058 /* Free any memory used in png_ptr struct (old method) */
1060 png_write_destroy(png_structp png_ptr)
1062 #ifdef PNG_SETJMP_SUPPORTED
1063 jmp_buf tmp_jmp; /* save jump buffer */
1065 png_error_ptr error_fn;
1066 png_error_ptr warning_fn;
1067 png_voidp error_ptr;
1068 #ifdef PNG_USER_MEM_SUPPORTED
1069 png_free_ptr free_fn;
1072 png_debug(1, "in png_write_destroy\n");
1073 /* free any memory zlib uses */
1074 deflateEnd(&png_ptr->zstream);
1076 /* free our memory. png_free checks NULL for us. */
1077 png_free(png_ptr, png_ptr->zbuf);
1078 png_free(png_ptr, png_ptr->row_buf);
1079 #ifndef PNG_NO_WRITE_FILTERING
1080 png_free(png_ptr, png_ptr->prev_row);
1081 png_free(png_ptr, png_ptr->sub_row);
1082 png_free(png_ptr, png_ptr->up_row);
1083 png_free(png_ptr, png_ptr->avg_row);
1084 png_free(png_ptr, png_ptr->paeth_row);
1087 #if defined(PNG_TIME_RFC1123_SUPPORTED)
1088 png_free(png_ptr, png_ptr->time_buffer);
1091 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
1092 png_free(png_ptr, png_ptr->prev_filters);
1093 png_free(png_ptr, png_ptr->filter_weights);
1094 png_free(png_ptr, png_ptr->inv_filter_weights);
1095 png_free(png_ptr, png_ptr->filter_costs);
1096 png_free(png_ptr, png_ptr->inv_filter_costs);
1099 #ifdef PNG_SETJMP_SUPPORTED
1100 /* reset structure */
1101 png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
1104 error_fn = png_ptr->error_fn;
1105 warning_fn = png_ptr->warning_fn;
1106 error_ptr = png_ptr->error_ptr;
1107 #ifdef PNG_USER_MEM_SUPPORTED
1108 free_fn = png_ptr->free_fn;
1111 png_memset(png_ptr, 0, png_sizeof (png_struct));
1113 png_ptr->error_fn = error_fn;
1114 png_ptr->warning_fn = warning_fn;
1115 png_ptr->error_ptr = error_ptr;
1116 #ifdef PNG_USER_MEM_SUPPORTED
1117 png_ptr->free_fn = free_fn;
1120 #ifdef PNG_SETJMP_SUPPORTED
1121 png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
1125 /* Allow the application to select one or more row filters to use. */
1127 png_set_filter(png_structp png_ptr, int method, int filters)
1129 png_debug(1, "in png_set_filter\n");
1130 if (png_ptr == NULL)
1132 #if defined(PNG_MNG_FEATURES_SUPPORTED)
1133 if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
1134 (method == PNG_INTRAPIXEL_DIFFERENCING))
1135 method = PNG_FILTER_TYPE_BASE;
1137 if (method == PNG_FILTER_TYPE_BASE)
1139 switch (filters & (PNG_ALL_FILTERS | 0x07))
1141 #ifndef PNG_NO_WRITE_FILTER
1144 case 7: png_warning(png_ptr, "Unknown row filter for method 0");
1145 #endif /* PNG_NO_WRITE_FILTER */
1146 case PNG_FILTER_VALUE_NONE:
1147 png_ptr->do_filter=PNG_FILTER_NONE; break;
1148 #ifndef PNG_NO_WRITE_FILTER
1149 case PNG_FILTER_VALUE_SUB:
1150 png_ptr->do_filter=PNG_FILTER_SUB; break;
1151 case PNG_FILTER_VALUE_UP:
1152 png_ptr->do_filter=PNG_FILTER_UP; break;
1153 case PNG_FILTER_VALUE_AVG:
1154 png_ptr->do_filter=PNG_FILTER_AVG; break;
1155 case PNG_FILTER_VALUE_PAETH:
1156 png_ptr->do_filter=PNG_FILTER_PAETH; break;
1157 default: png_ptr->do_filter = (png_byte)filters; break;
1159 default: png_warning(png_ptr, "Unknown row filter for method 0");
1160 #endif /* PNG_NO_WRITE_FILTER */
1163 /* If we have allocated the row_buf, this means we have already started
1164 * with the image and we should have allocated all of the filter buffers
1165 * that have been selected. If prev_row isn't already allocated, then
1166 * it is too late to start using the filters that need it, since we
1167 * will be missing the data in the previous row. If an application
1168 * wants to start and stop using particular filters during compression,
1169 * it should start out with all of the filters, and then add and
1170 * remove them after the start of compression.
1172 if (png_ptr->row_buf != NULL)
1174 #ifndef PNG_NO_WRITE_FILTER
1175 if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
1177 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1178 (png_ptr->rowbytes + 1));
1179 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1182 if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
1184 if (png_ptr->prev_row == NULL)
1186 png_warning(png_ptr, "Can't add Up filter after starting");
1187 png_ptr->do_filter &= ~PNG_FILTER_UP;
1191 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1192 (png_ptr->rowbytes + 1));
1193 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1197 if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
1199 if (png_ptr->prev_row == NULL)
1201 png_warning(png_ptr, "Can't add Average filter after starting");
1202 png_ptr->do_filter &= ~PNG_FILTER_AVG;
1206 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1207 (png_ptr->rowbytes + 1));
1208 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1212 if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
1213 png_ptr->paeth_row == NULL)
1215 if (png_ptr->prev_row == NULL)
1217 png_warning(png_ptr, "Can't add Paeth filter after starting");
1218 png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
1222 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1223 (png_ptr->rowbytes + 1));
1224 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1228 if (png_ptr->do_filter == PNG_NO_FILTERS)
1229 #endif /* PNG_NO_WRITE_FILTER */
1230 png_ptr->do_filter = PNG_FILTER_NONE;
1234 png_error(png_ptr, "Unknown custom filter method");
1237 /* This allows us to influence the way in which libpng chooses the "best"
1238 * filter for the current scanline. While the "minimum-sum-of-absolute-
1239 * differences metric is relatively fast and effective, there is some
1240 * question as to whether it can be improved upon by trying to keep the
1241 * filtered data going to zlib more consistent, hopefully resulting in
1242 * better compression.
1244 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* GRR 970116 */
1246 png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,
1247 int num_weights, png_doublep filter_weights,
1248 png_doublep filter_costs)
1252 png_debug(1, "in png_set_filter_heuristics\n");
1253 if (png_ptr == NULL)
1255 if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)
1257 png_warning(png_ptr, "Unknown filter heuristic method");
1261 if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT)
1263 heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
1266 if (num_weights < 0 || filter_weights == NULL ||
1267 heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
1272 png_ptr->num_prev_filters = (png_byte)num_weights;
1273 png_ptr->heuristic_method = (png_byte)heuristic_method;
1275 if (num_weights > 0)
1277 if (png_ptr->prev_filters == NULL)
1279 png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
1280 (png_uint_32)(png_sizeof(png_byte) * num_weights));
1282 /* To make sure that the weighting starts out fairly */
1283 for (i = 0; i < num_weights; i++)
1285 png_ptr->prev_filters[i] = 255;
1289 if (png_ptr->filter_weights == NULL)
1291 png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
1292 (png_uint_32)(png_sizeof(png_uint_16) * num_weights));
1294 png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
1295 (png_uint_32)(png_sizeof(png_uint_16) * num_weights));
1296 for (i = 0; i < num_weights; i++)
1298 png_ptr->inv_filter_weights[i] =
1299 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1303 for (i = 0; i < num_weights; i++)
1305 if (filter_weights[i] < 0.0)
1307 png_ptr->inv_filter_weights[i] =
1308 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1312 png_ptr->inv_filter_weights[i] =
1313 (png_uint_16)((double)PNG_WEIGHT_FACTOR*filter_weights[i]+0.5);
1314 png_ptr->filter_weights[i] =
1315 (png_uint_16)((double)PNG_WEIGHT_FACTOR/filter_weights[i]+0.5);
1320 /* If, in the future, there are other filter methods, this would
1321 * need to be based on png_ptr->filter.
1323 if (png_ptr->filter_costs == NULL)
1325 png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
1326 (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
1328 png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
1329 (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
1331 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
1333 png_ptr->inv_filter_costs[i] =
1334 png_ptr->filter_costs[i] = PNG_COST_FACTOR;
1338 /* Here is where we set the relative costs of the different filters. We
1339 * should take the desired compression level into account when setting
1340 * the costs, so that Paeth, for instance, has a high relative cost at low
1341 * compression levels, while it has a lower relative cost at higher
1342 * compression settings. The filter types are in order of increasing
1343 * relative cost, so it would be possible to do this with an algorithm.
1345 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
1347 if (filter_costs == NULL || filter_costs[i] < 0.0)
1349 png_ptr->inv_filter_costs[i] =
1350 png_ptr->filter_costs[i] = PNG_COST_FACTOR;
1352 else if (filter_costs[i] >= 1.0)
1354 png_ptr->inv_filter_costs[i] =
1355 (png_uint_16)((double)PNG_COST_FACTOR / filter_costs[i] + 0.5);
1356 png_ptr->filter_costs[i] =
1357 (png_uint_16)((double)PNG_COST_FACTOR * filter_costs[i] + 0.5);
1361 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1364 png_set_compression_level(png_structp png_ptr, int level)
1366 png_debug(1, "in png_set_compression_level\n");
1367 if (png_ptr == NULL)
1369 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
1370 png_ptr->zlib_level = level;
1374 png_set_compression_mem_level(png_structp png_ptr, int mem_level)
1376 png_debug(1, "in png_set_compression_mem_level\n");
1377 if (png_ptr == NULL)
1379 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
1380 png_ptr->zlib_mem_level = mem_level;
1384 png_set_compression_strategy(png_structp png_ptr, int strategy)
1386 png_debug(1, "in png_set_compression_strategy\n");
1387 if (png_ptr == NULL)
1389 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1390 png_ptr->zlib_strategy = strategy;
1394 png_set_compression_window_bits(png_structp png_ptr, int window_bits)
1396 if (png_ptr == NULL)
1398 if (window_bits > 15)
1399 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1400 else if (window_bits < 8)
1401 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1403 /* avoid libpng bug with 256-byte windows */
1404 if (window_bits == 8)
1406 png_warning(png_ptr, "Compression window is being reset to 512");
1410 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;
1411 png_ptr->zlib_window_bits = window_bits;
1415 png_set_compression_method(png_structp png_ptr, int method)
1417 png_debug(1, "in png_set_compression_method\n");
1418 if (png_ptr == NULL)
1421 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1422 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
1423 png_ptr->zlib_method = method;
1427 png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
1429 if (png_ptr == NULL)
1431 png_ptr->write_row_fn = write_row_fn;
1434 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
1436 png_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
1437 write_user_transform_fn)
1439 png_debug(1, "in png_set_write_user_transform_fn\n");
1440 if (png_ptr == NULL)
1442 png_ptr->transformations |= PNG_USER_TRANSFORM;
1443 png_ptr->write_user_transform_fn = write_user_transform_fn;
1448 #if defined(PNG_INFO_IMAGE_SUPPORTED)
1450 png_write_png(png_structp png_ptr, png_infop info_ptr,
1451 int transforms, voidp params)
1453 if (png_ptr == NULL || info_ptr == NULL)
1455 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1456 /* invert the alpha channel from opacity to transparency */
1457 if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1458 png_set_invert_alpha(png_ptr);
1461 /* Write the file header information. */
1462 png_write_info(png_ptr, info_ptr);
1464 /* ------ these transformations don't touch the info structure ------- */
1466 #if defined(PNG_WRITE_INVERT_SUPPORTED)
1467 /* invert monochrome pixels */
1468 if (transforms & PNG_TRANSFORM_INVERT_MONO)
1469 png_set_invert_mono(png_ptr);
1472 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
1473 /* Shift the pixels up to a legal bit depth and fill in
1474 * as appropriate to correctly scale the image.
1476 if ((transforms & PNG_TRANSFORM_SHIFT)
1477 && (info_ptr->valid & PNG_INFO_sBIT))
1478 png_set_shift(png_ptr, &info_ptr->sig_bit);
1481 #if defined(PNG_WRITE_PACK_SUPPORTED)
1482 /* pack pixels into bytes */
1483 if (transforms & PNG_TRANSFORM_PACKING)
1484 png_set_packing(png_ptr);
1487 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1488 /* swap location of alpha bytes from ARGB to RGBA */
1489 if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1490 png_set_swap_alpha(png_ptr);
1493 #if defined(PNG_WRITE_FILLER_SUPPORTED)
1494 /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
1495 * RGB (4 channels -> 3 channels). The second parameter is not used.
1497 if (transforms & PNG_TRANSFORM_STRIP_FILLER)
1498 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1501 #if defined(PNG_WRITE_BGR_SUPPORTED)
1502 /* flip BGR pixels to RGB */
1503 if (transforms & PNG_TRANSFORM_BGR)
1504 png_set_bgr(png_ptr);
1507 #if defined(PNG_WRITE_SWAP_SUPPORTED)
1508 /* swap bytes of 16-bit files to most significant byte first */
1509 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1510 png_set_swap(png_ptr);
1513 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1514 /* swap bits of 1, 2, 4 bit packed pixel formats */
1515 if (transforms & PNG_TRANSFORM_PACKSWAP)
1516 png_set_packswap(png_ptr);
1519 /* ----------------------- end of transformations ------------------- */
1521 /* write the bits */
1522 if (info_ptr->valid & PNG_INFO_IDAT)
1523 png_write_image(png_ptr, info_ptr->row_pointers);
1525 /* It is REQUIRED to call this to finish writing the rest of the file */
1526 png_write_end(png_ptr, info_ptr);
1528 transforms = transforms; /* quiet compiler warnings */
1532 #endif /* PNG_WRITE_SUPPORTED */