2 /* pngwrite.c - general routines to write a PNG file
4 * libpng 1.2.0 - September 1, 2001
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2001 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->mode & PNG_WROTE_INFO_BEFORE_PLTE))
31 png_write_sig(png_ptr); /* write PNG signature */
32 #if defined(PNG_MNG_FEATURES_SUPPORTED)
33 if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
35 png_warning(png_ptr,"MNG features are not allowed in a PNG datastream\n");
36 png_ptr->mng_features_permitted=0;
39 /* write IHDR information. */
40 png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
41 info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
42 info_ptr->filter_type,
43 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
44 info_ptr->interlace_type);
48 /* the rest of these check to see if the valid field has the appropriate
49 flag set, and if it does, writes the chunk. */
50 #if defined(PNG_WRITE_gAMA_SUPPORTED)
51 if (info_ptr->valid & PNG_INFO_gAMA)
53 # ifdef PNG_FLOATING_POINT_SUPPORTED
54 png_write_gAMA(png_ptr, info_ptr->gamma);
56 #ifdef PNG_FIXED_POINT_SUPPORTED
57 png_write_gAMA_fixed(png_ptr, info_ptr->int_gamma);
62 #if defined(PNG_WRITE_sRGB_SUPPORTED)
63 if (info_ptr->valid & PNG_INFO_sRGB)
64 png_write_sRGB(png_ptr, (int)info_ptr->srgb_intent);
66 #if defined(PNG_WRITE_iCCP_SUPPORTED)
67 if (info_ptr->valid & PNG_INFO_iCCP)
68 png_write_iCCP(png_ptr, info_ptr->iccp_name, PNG_COMPRESSION_TYPE_BASE,
69 info_ptr->iccp_profile, (int)info_ptr->iccp_proflen);
71 #if defined(PNG_WRITE_sBIT_SUPPORTED)
72 if (info_ptr->valid & PNG_INFO_sBIT)
73 png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
75 #if defined(PNG_WRITE_cHRM_SUPPORTED)
76 if (info_ptr->valid & PNG_INFO_cHRM)
78 #ifdef PNG_FLOATING_POINT_SUPPORTED
79 png_write_cHRM(png_ptr,
80 info_ptr->x_white, info_ptr->y_white,
81 info_ptr->x_red, info_ptr->y_red,
82 info_ptr->x_green, info_ptr->y_green,
83 info_ptr->x_blue, info_ptr->y_blue);
85 # ifdef PNG_FIXED_POINT_SUPPORTED
86 png_write_cHRM_fixed(png_ptr,
87 info_ptr->int_x_white, info_ptr->int_y_white,
88 info_ptr->int_x_red, info_ptr->int_y_red,
89 info_ptr->int_x_green, info_ptr->int_y_green,
90 info_ptr->int_x_blue, info_ptr->int_y_blue);
95 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
96 if (info_ptr->unknown_chunks_num)
98 png_unknown_chunk *up;
100 png_debug(5, "writing extra chunks\n");
102 for (up = info_ptr->unknown_chunks;
103 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
106 int keep=png_handle_as_unknown(png_ptr, up->name);
107 if (keep != HANDLE_CHUNK_NEVER &&
108 up->location && (!(up->location & PNG_HAVE_PLTE)) &&
109 ((up->name[3] & 0x20) || keep == HANDLE_CHUNK_ALWAYS ||
110 (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
112 png_write_chunk(png_ptr, up->name, up->data, up->size);
117 png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
122 png_write_info(png_structp png_ptr, png_infop info_ptr)
124 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
128 png_debug(1, "in png_write_info\n");
130 png_write_info_before_PLTE(png_ptr, info_ptr);
132 if (info_ptr->valid & PNG_INFO_PLTE)
133 png_write_PLTE(png_ptr, info_ptr->palette,
134 (png_uint_32)info_ptr->num_palette);
135 else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
136 png_error(png_ptr, "Valid palette required for paletted images\n");
138 #if defined(PNG_WRITE_tRNS_SUPPORTED)
139 if (info_ptr->valid & PNG_INFO_tRNS)
141 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
142 /* invert the alpha channel (in tRNS) */
143 if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
144 info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
147 for (j=0; j<(int)info_ptr->num_trans; j++)
148 info_ptr->trans[j] = (png_byte)(255 - info_ptr->trans[j]);
151 png_write_tRNS(png_ptr, info_ptr->trans, &(info_ptr->trans_values),
152 info_ptr->num_trans, info_ptr->color_type);
155 #if defined(PNG_WRITE_bKGD_SUPPORTED)
156 if (info_ptr->valid & PNG_INFO_bKGD)
157 png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
159 #if defined(PNG_WRITE_hIST_SUPPORTED)
160 if (info_ptr->valid & PNG_INFO_hIST)
161 png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
163 #if defined(PNG_WRITE_oFFs_SUPPORTED)
164 if (info_ptr->valid & PNG_INFO_oFFs)
165 png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
166 info_ptr->offset_unit_type);
168 #if defined(PNG_WRITE_pCAL_SUPPORTED)
169 if (info_ptr->valid & PNG_INFO_pCAL)
170 png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
171 info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
172 info_ptr->pcal_units, info_ptr->pcal_params);
174 #if defined(PNG_WRITE_sCAL_SUPPORTED)
175 if (info_ptr->valid & PNG_INFO_sCAL)
176 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
177 png_write_sCAL(png_ptr, (int)info_ptr->scal_unit,
178 info_ptr->scal_pixel_width, info_ptr->scal_pixel_height);
180 #ifdef PNG_FIXED_POINT_SUPPORTED
181 png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
182 info_ptr->scal_s_width, info_ptr->scal_s_height);
185 "png_write_sCAL not supported; sCAL chunk not written.\n");
189 #if defined(PNG_WRITE_pHYs_SUPPORTED)
190 if (info_ptr->valid & PNG_INFO_pHYs)
191 png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
192 info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
194 #if defined(PNG_WRITE_tIME_SUPPORTED)
195 if (info_ptr->valid & PNG_INFO_tIME)
197 png_write_tIME(png_ptr, &(info_ptr->mod_time));
198 png_ptr->mode |= PNG_WROTE_tIME;
201 #if defined(PNG_WRITE_sPLT_SUPPORTED)
202 if (info_ptr->valid & PNG_INFO_sPLT)
203 for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
204 png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
206 #if defined(PNG_WRITE_TEXT_SUPPORTED)
207 /* Check to see if we need to write text chunks */
208 for (i = 0; i < info_ptr->num_text; i++)
210 png_debug2(2, "Writing header text chunk %d, type %d\n", i,
211 info_ptr->text[i].compression);
212 /* an internationalized chunk? */
213 if (info_ptr->text[i].compression > 0)
215 #if defined(PNG_WRITE_iTXt_SUPPORTED)
216 /* write international chunk */
217 png_write_iTXt(png_ptr,
218 info_ptr->text[i].compression,
219 info_ptr->text[i].key,
220 info_ptr->text[i].lang,
221 info_ptr->text[i].lang_key,
222 info_ptr->text[i].text);
224 png_warning(png_ptr, "Unable to write international text\n");
226 /* Mark this chunk as written */
227 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
229 /* If we want a compressed text chunk */
230 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
232 #if defined(PNG_WRITE_zTXt_SUPPORTED)
233 /* write compressed chunk */
234 png_write_zTXt(png_ptr, info_ptr->text[i].key,
235 info_ptr->text[i].text, 0,
236 info_ptr->text[i].compression);
238 png_warning(png_ptr, "Unable to write compressed text\n");
240 /* Mark this chunk as written */
241 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
243 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
245 #if defined(PNG_WRITE_tEXt_SUPPORTED)
246 /* write uncompressed chunk */
247 png_write_tEXt(png_ptr, info_ptr->text[i].key,
248 info_ptr->text[i].text,
251 png_warning(png_ptr, "Unable to write uncompressed text\n");
253 /* Mark this chunk as written */
254 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
258 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
259 if (info_ptr->unknown_chunks_num)
261 png_unknown_chunk *up;
263 png_debug(5, "writing extra chunks\n");
265 for (up = info_ptr->unknown_chunks;
266 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
269 int keep=png_handle_as_unknown(png_ptr, up->name);
270 if (keep != HANDLE_CHUNK_NEVER &&
271 up->location && (up->location & PNG_HAVE_PLTE) &&
272 !(up->location & PNG_HAVE_IDAT) &&
273 ((up->name[3] & 0x20) || keep == HANDLE_CHUNK_ALWAYS ||
274 (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
276 png_write_chunk(png_ptr, up->name, up->data, up->size);
283 /* Writes the end of the PNG file. If you don't want to write comments or
284 * time information, you can pass NULL for info. If you already wrote these
285 * in png_write_info(), do not write them again here. If you have long
286 * comments, I suggest writing them here, and compressing them.
289 png_write_end(png_structp png_ptr, png_infop info_ptr)
291 png_debug(1, "in png_write_end\n");
292 if (!(png_ptr->mode & PNG_HAVE_IDAT))
293 png_error(png_ptr, "No IDATs written into file");
295 /* see if user wants us to write information chunks */
296 if (info_ptr != NULL)
298 #if defined(PNG_WRITE_TEXT_SUPPORTED)
299 int i; /* local index variable */
301 #if defined(PNG_WRITE_tIME_SUPPORTED)
302 /* check to see if user has supplied a time chunk */
303 if ((info_ptr->valid & PNG_INFO_tIME) &&
304 !(png_ptr->mode & PNG_WROTE_tIME))
305 png_write_tIME(png_ptr, &(info_ptr->mod_time));
307 #if defined(PNG_WRITE_TEXT_SUPPORTED)
308 /* loop through comment chunks */
309 for (i = 0; i < info_ptr->num_text; i++)
311 png_debug2(2, "Writing trailer text chunk %d, type %d\n", i,
312 info_ptr->text[i].compression);
313 /* an internationalized chunk? */
314 if (info_ptr->text[i].compression > 0)
316 #if defined(PNG_WRITE_iTXt_SUPPORTED)
317 /* write international chunk */
318 png_write_iTXt(png_ptr,
319 info_ptr->text[i].compression,
320 info_ptr->text[i].key,
321 info_ptr->text[i].lang,
322 info_ptr->text[i].lang_key,
323 info_ptr->text[i].text);
325 png_warning(png_ptr, "Unable to write international text\n");
327 /* Mark this chunk as written */
328 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
330 else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
332 #if defined(PNG_WRITE_zTXt_SUPPORTED)
333 /* write compressed chunk */
334 png_write_zTXt(png_ptr, info_ptr->text[i].key,
335 info_ptr->text[i].text, 0,
336 info_ptr->text[i].compression);
338 png_warning(png_ptr, "Unable to write compressed text\n");
340 /* Mark this chunk as written */
341 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
343 else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
345 #if defined(PNG_WRITE_tEXt_SUPPORTED)
346 /* write uncompressed chunk */
347 png_write_tEXt(png_ptr, info_ptr->text[i].key,
348 info_ptr->text[i].text, 0);
350 png_warning(png_ptr, "Unable to write uncompressed text\n");
353 /* Mark this chunk as written */
354 info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
358 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
359 if (info_ptr->unknown_chunks_num)
361 png_unknown_chunk *up;
363 png_debug(5, "writing extra chunks\n");
365 for (up = info_ptr->unknown_chunks;
366 up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
369 int keep=png_handle_as_unknown(png_ptr, up->name);
370 if (keep != HANDLE_CHUNK_NEVER &&
371 up->location && (up->location & PNG_AFTER_IDAT) &&
372 ((up->name[3] & 0x20) || keep == HANDLE_CHUNK_ALWAYS ||
373 (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
375 png_write_chunk(png_ptr, up->name, up->data, up->size);
382 png_ptr->mode |= PNG_AFTER_IDAT;
384 /* write end of PNG file */
385 png_write_IEND(png_ptr);
387 /* This flush, added in libpng-1.0.8, causes some applications to crash
388 because they do not set png_ptr->output_flush_fn */
393 #if defined(PNG_WRITE_tIME_SUPPORTED)
394 #if !defined(_WIN32_WCE)
395 /* "time.h" functions are not supported on WindowsCE */
397 png_convert_from_struct_tm(png_timep ptime, struct tm FAR * ttime)
399 png_debug(1, "in png_convert_from_struct_tm\n");
400 ptime->year = (png_uint_16)(1900 + ttime->tm_year);
401 ptime->month = (png_byte)(ttime->tm_mon + 1);
402 ptime->day = (png_byte)ttime->tm_mday;
403 ptime->hour = (png_byte)ttime->tm_hour;
404 ptime->minute = (png_byte)ttime->tm_min;
405 ptime->second = (png_byte)ttime->tm_sec;
409 png_convert_from_time_t(png_timep ptime, time_t ttime)
413 png_debug(1, "in png_convert_from_time_t\n");
414 tbuf = gmtime(&ttime);
415 png_convert_from_struct_tm(ptime, tbuf);
420 /* Initialize png_ptr structure, and allocate any memory needed */
422 png_create_write_struct(png_const_charp user_png_ver, png_voidp error_ptr,
423 png_error_ptr error_fn, png_error_ptr warn_fn)
425 #ifdef PNG_USER_MEM_SUPPORTED
426 return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
427 warn_fn, NULL, NULL, NULL));
430 /* Alternate initialize png_ptr structure, and allocate any memory needed */
432 png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
433 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
434 png_malloc_ptr malloc_fn, png_free_ptr free_fn)
436 #endif /* PNG_USER_MEM_SUPPORTED */
438 #ifdef PNG_SETJMP_SUPPORTED
439 #ifdef USE_FAR_KEYWORD
444 png_debug(1, "in png_create_write_struct\n");
445 #ifdef PNG_USER_MEM_SUPPORTED
446 if ((png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
447 (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr)) == NULL)
449 if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
450 #endif /* PNG_USER_MEM_SUPPORTED */
452 return ((png_structp)NULL);
455 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
456 png_init_mmx_flags(png_ptr); /* 1.2.0 addition */
459 #ifdef PNG_SETJMP_SUPPORTED
460 #ifdef USE_FAR_KEYWORD
463 if (setjmp(png_ptr->jmpbuf))
466 png_free(png_ptr, png_ptr->zbuf);
468 png_destroy_struct(png_ptr);
469 return ((png_structp)NULL);
471 #ifdef USE_FAR_KEYWORD
472 png_memcpy(png_ptr->jmpbuf,jmpbuf,sizeof(jmp_buf));
476 #ifdef PNG_USER_MEM_SUPPORTED
477 png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
478 #endif /* PNG_USER_MEM_SUPPORTED */
479 png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
484 if(user_png_ver[i] != png_libpng_ver[i])
485 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
486 } while (png_libpng_ver[i++]);
488 if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
490 /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
491 * we must recompile any applications that use any older library version.
492 * For versions after libpng 1.0, we will be compatible, so we need
493 * only check the first digit.
495 if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
496 (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
497 (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
499 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
503 sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
505 png_warning(png_ptr, msg);
507 sprintf(msg, "Application is running with png.c from libpng-%.20s",
509 png_warning(png_ptr, msg);
511 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
515 "Incompatible libpng version in application and library");
519 /* initialize zbuf - compression buffer */
520 png_ptr->zbuf_size = PNG_ZBUF_SIZE;
521 png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
522 (png_uint_32)png_ptr->zbuf_size);
524 png_set_write_fn(png_ptr, NULL, NULL, NULL);
526 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
527 png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
531 return ((png_structp)png_ptr);
534 /* Initialize png_ptr structure, and allocate any memory needed */
535 #undef png_write_init
537 png_write_init(png_structp png_ptr)
539 /* We only come here via pre-1.0.7-compiled applications */
540 png_write_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
543 #undef png_write_init_2
545 png_write_init_2(png_structp png_ptr, png_const_charp user_png_ver,
546 png_size_t png_struct_size, png_size_t png_info_size)
548 /* We only come here via pre-1.0.12-compiled applications */
549 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
550 if(sizeof(png_struct) > png_struct_size || sizeof(png_info) > png_info_size)
553 png_ptr->warning_fn=(png_error_ptr)NULL;
556 sprintf(msg, "Application was compiled with png.h from libpng-%.20s",
558 png_warning(png_ptr, msg);
560 sprintf(msg, "Application is running with png.c from libpng-%.20s",
562 png_warning(png_ptr, msg);
565 if(sizeof(png_struct) > png_struct_size)
567 png_ptr->error_fn=(png_error_ptr)NULL;
568 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
572 "The png struct allocated by the application for writing is too small.");
574 if(sizeof(png_info) > png_info_size)
576 png_ptr->error_fn=(png_error_ptr)NULL;
577 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
581 "The info struct allocated by the application for writing is too small.");
583 png_write_init_3(&png_ptr, user_png_ver, png_struct_size);
588 png_write_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
589 png_size_t png_struct_size)
591 png_structp png_ptr=*ptr_ptr;
592 #ifdef PNG_SETJMP_SUPPORTED
593 jmp_buf tmp_jmp; /* to save current jump buffer */
598 if (user_png_ver[i] != png_libpng_ver[i])
600 #ifdef PNG_LEGACY_SUPPORTED
601 png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
603 png_ptr->warning_fn=(png_error_ptr)NULL;
605 "Application uses deprecated png_write_init() and should be recompiled.");
609 } while (png_libpng_ver[i++]);
611 png_debug(1, "in png_write_init_3\n");
613 #ifdef PNG_SETJMP_SUPPORTED
614 /* save jump buffer and error functions */
615 png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
618 if (sizeof(png_struct) > png_struct_size)
620 png_destroy_struct(png_ptr);
621 png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
625 /* reset all variables to 0 */
626 png_memset(png_ptr, 0, sizeof (png_struct));
628 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
629 png_init_mmx_flags(png_ptr); /* 1.2.0 addition */
632 #ifdef PNG_SETJMP_SUPPORTED
633 /* restore jump buffer */
634 png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
637 png_set_write_fn(png_ptr, NULL, NULL, NULL);
639 /* initialize zbuf - compression buffer */
640 png_ptr->zbuf_size = PNG_ZBUF_SIZE;
641 png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
642 (png_uint_32)png_ptr->zbuf_size);
644 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
645 png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
650 /* Write a few rows of image data. If the image is interlaced,
651 * either you will have to write the 7 sub images, or, if you
652 * have called png_set_interlace_handling(), you will have to
653 * "write" the image seven times.
656 png_write_rows(png_structp png_ptr, png_bytepp row,
657 png_uint_32 num_rows)
659 png_uint_32 i; /* row counter */
660 png_bytepp rp; /* row pointer */
662 png_debug(1, "in png_write_rows\n");
663 /* loop through the rows */
664 for (i = 0, rp = row; i < num_rows; i++, rp++)
666 png_write_row(png_ptr, *rp);
670 /* Write the image. You only need to call this function once, even
671 * if you are writing an interlaced image.
674 png_write_image(png_structp png_ptr, png_bytepp image)
676 png_uint_32 i; /* row index */
677 int pass, num_pass; /* pass variables */
678 png_bytepp rp; /* points to current row */
680 png_debug(1, "in png_write_image\n");
681 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
682 /* intialize interlace handling. If image is not interlaced,
683 this will set pass to 1 */
684 num_pass = png_set_interlace_handling(png_ptr);
688 /* loop through passes */
689 for (pass = 0; pass < num_pass; pass++)
691 /* loop through image */
692 for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
694 png_write_row(png_ptr, *rp);
699 /* called by user to write a row of image data */
701 png_write_row(png_structp png_ptr, png_bytep row)
703 png_debug2(1, "in png_write_row (row %ld, pass %d)\n",
704 png_ptr->row_number, png_ptr->pass);
705 /* initialize transformations and other stuff if first time */
706 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
708 /* check for transforms that have been set but were defined out */
709 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
710 if (png_ptr->transformations & PNG_INVERT_MONO)
711 png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined.");
713 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
714 if (png_ptr->transformations & PNG_FILLER)
715 png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined.");
717 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && defined(PNG_READ_PACKSWAP_SUPPORTED)
718 if (png_ptr->transformations & PNG_PACKSWAP)
719 png_warning(png_ptr, "PNG_WRITE_PACKSWAP_SUPPORTED is not defined.");
721 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
722 if (png_ptr->transformations & PNG_PACK)
723 png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined.");
725 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
726 if (png_ptr->transformations & PNG_SHIFT)
727 png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined.");
729 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
730 if (png_ptr->transformations & PNG_BGR)
731 png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined.");
733 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
734 if (png_ptr->transformations & PNG_SWAP_BYTES)
735 png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined.");
738 png_write_start_row(png_ptr);
741 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
742 /* if interlaced and not interested in row, return */
743 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
745 switch (png_ptr->pass)
748 if (png_ptr->row_number & 0x07)
750 png_write_finish_row(png_ptr);
755 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
757 png_write_finish_row(png_ptr);
762 if ((png_ptr->row_number & 0x07) != 4)
764 png_write_finish_row(png_ptr);
769 if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
771 png_write_finish_row(png_ptr);
776 if ((png_ptr->row_number & 0x03) != 2)
778 png_write_finish_row(png_ptr);
783 if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
785 png_write_finish_row(png_ptr);
790 if (!(png_ptr->row_number & 0x01))
792 png_write_finish_row(png_ptr);
800 /* set up row info for transformations */
801 png_ptr->row_info.color_type = png_ptr->color_type;
802 png_ptr->row_info.width = png_ptr->usr_width;
803 png_ptr->row_info.channels = png_ptr->usr_channels;
804 png_ptr->row_info.bit_depth = png_ptr->usr_bit_depth;
805 png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
806 png_ptr->row_info.channels);
808 png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
809 (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
811 png_debug1(3, "row_info->color_type = %d\n", png_ptr->row_info.color_type);
812 png_debug1(3, "row_info->width = %lu\n", png_ptr->row_info.width);
813 png_debug1(3, "row_info->channels = %d\n", png_ptr->row_info.channels);
814 png_debug1(3, "row_info->bit_depth = %d\n", png_ptr->row_info.bit_depth);
815 png_debug1(3, "row_info->pixel_depth = %d\n", png_ptr->row_info.pixel_depth);
816 png_debug1(3, "row_info->rowbytes = %lu\n", png_ptr->row_info.rowbytes);
818 /* Copy user's row into buffer, leaving room for filter byte. */
819 png_memcpy_check(png_ptr, png_ptr->row_buf + 1, row,
820 png_ptr->row_info.rowbytes);
822 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
823 /* handle interlacing */
824 if (png_ptr->interlaced && png_ptr->pass < 6 &&
825 (png_ptr->transformations & PNG_INTERLACE))
827 png_do_write_interlace(&(png_ptr->row_info),
828 png_ptr->row_buf + 1, png_ptr->pass);
829 /* this should always get caught above, but still ... */
830 if (!(png_ptr->row_info.width))
832 png_write_finish_row(png_ptr);
838 /* handle other transformations */
839 if (png_ptr->transformations)
840 png_do_write_transformations(png_ptr);
842 #if defined(PNG_MNG_FEATURES_SUPPORTED)
843 /* Write filter_method 64 (intrapixel differencing) only if
844 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
845 * 2. Libpng did not write a PNG signature (this filter_method is only
846 * used in PNG datastreams that are embedded in MNG datastreams) and
847 * 3. The application called png_permit_mng_features with a mask that
848 * included PNG_FLAG_MNG_FILTER_64 and
849 * 4. The filter_method is 64 and
850 * 5. The color_type is RGB or RGBA
852 if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
853 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
855 /* Intrapixel differencing */
856 png_do_write_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
860 /* Find a filter if necessary, filter the row and write it out. */
861 png_write_find_filter(png_ptr, &(png_ptr->row_info));
863 if (png_ptr->write_row_fn != NULL)
864 (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
867 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
868 /* Set the automatic flush interval or 0 to turn flushing off */
870 png_set_flush(png_structp png_ptr, int nrows)
872 png_debug(1, "in png_set_flush\n");
873 png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
876 /* flush the current output buffers now */
878 png_write_flush(png_structp png_ptr)
882 png_debug(1, "in png_write_flush\n");
883 /* We have already written out all of the data */
884 if (png_ptr->row_number >= png_ptr->num_rows)
891 /* compress the data */
892 ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);
895 /* check for compression errors */
898 if (png_ptr->zstream.msg != NULL)
899 png_error(png_ptr, png_ptr->zstream.msg);
901 png_error(png_ptr, "zlib error");
904 if (!(png_ptr->zstream.avail_out))
906 /* write the IDAT and reset the zlib output buffer */
907 png_write_IDAT(png_ptr, png_ptr->zbuf,
909 png_ptr->zstream.next_out = png_ptr->zbuf;
910 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
913 } while(wrote_IDAT == 1);
915 /* If there is any data left to be output, write it into a new IDAT */
916 if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)
918 /* write the IDAT and reset the zlib output buffer */
919 png_write_IDAT(png_ptr, png_ptr->zbuf,
920 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
921 png_ptr->zstream.next_out = png_ptr->zbuf;
922 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
924 png_ptr->flush_rows = 0;
927 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
929 /* free all memory used by the write */
931 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
933 png_structp png_ptr = NULL;
934 png_infop info_ptr = NULL;
935 #ifdef PNG_USER_MEM_SUPPORTED
936 png_free_ptr free_fn = NULL;
937 png_voidp mem_ptr = NULL;
940 png_debug(1, "in png_destroy_write_struct\n");
941 if (png_ptr_ptr != NULL)
943 png_ptr = *png_ptr_ptr;
944 #ifdef PNG_USER_MEM_SUPPORTED
945 free_fn = png_ptr->free_fn;
949 if (info_ptr_ptr != NULL)
950 info_ptr = *info_ptr_ptr;
952 if (info_ptr != NULL)
954 png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
956 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
957 if (png_ptr->num_chunk_list)
959 png_free(png_ptr, png_ptr->chunk_list);
960 png_ptr->chunk_list=NULL;
961 png_ptr->num_chunk_list=0;
965 #ifdef PNG_USER_MEM_SUPPORTED
966 png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
969 png_destroy_struct((png_voidp)info_ptr);
971 *info_ptr_ptr = (png_infop)NULL;
976 png_write_destroy(png_ptr);
977 #ifdef PNG_USER_MEM_SUPPORTED
978 png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
981 png_destroy_struct((png_voidp)png_ptr);
983 *png_ptr_ptr = (png_structp)NULL;
988 /* Free any memory used in png_ptr struct (old method) */
990 png_write_destroy(png_structp png_ptr)
992 #ifdef PNG_SETJMP_SUPPORTED
993 jmp_buf tmp_jmp; /* save jump buffer */
995 png_error_ptr error_fn;
996 png_error_ptr warning_fn;
998 #ifdef PNG_USER_MEM_SUPPORTED
999 png_free_ptr free_fn;
1002 png_debug(1, "in png_write_destroy\n");
1003 /* free any memory zlib uses */
1004 deflateEnd(&png_ptr->zstream);
1006 /* free our memory. png_free checks NULL for us. */
1007 png_free(png_ptr, png_ptr->zbuf);
1008 png_free(png_ptr, png_ptr->row_buf);
1009 png_free(png_ptr, png_ptr->prev_row);
1010 png_free(png_ptr, png_ptr->sub_row);
1011 png_free(png_ptr, png_ptr->up_row);
1012 png_free(png_ptr, png_ptr->avg_row);
1013 png_free(png_ptr, png_ptr->paeth_row);
1015 #if defined(PNG_TIME_RFC1123_SUPPORTED)
1016 png_free(png_ptr, png_ptr->time_buffer);
1019 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
1020 png_free(png_ptr, png_ptr->prev_filters);
1021 png_free(png_ptr, png_ptr->filter_weights);
1022 png_free(png_ptr, png_ptr->inv_filter_weights);
1023 png_free(png_ptr, png_ptr->filter_costs);
1024 png_free(png_ptr, png_ptr->inv_filter_costs);
1027 #ifdef PNG_SETJMP_SUPPORTED
1028 /* reset structure */
1029 png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
1032 error_fn = png_ptr->error_fn;
1033 warning_fn = png_ptr->warning_fn;
1034 error_ptr = png_ptr->error_ptr;
1035 #ifdef PNG_USER_MEM_SUPPORTED
1036 free_fn = png_ptr->free_fn;
1039 png_memset(png_ptr, 0, sizeof (png_struct));
1041 png_ptr->error_fn = error_fn;
1042 png_ptr->warning_fn = warning_fn;
1043 png_ptr->error_ptr = error_ptr;
1044 #ifdef PNG_USER_MEM_SUPPORTED
1045 png_ptr->free_fn = free_fn;
1048 #ifdef PNG_SETJMP_SUPPORTED
1049 png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
1053 /* Allow the application to select one or more row filters to use. */
1055 png_set_filter(png_structp png_ptr, int method, int filters)
1057 png_debug(1, "in png_set_filter\n");
1058 #if defined(PNG_MNG_FEATURES_SUPPORTED)
1059 if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
1060 (method == PNG_INTRAPIXEL_DIFFERENCING))
1061 method = PNG_FILTER_TYPE_BASE;
1063 if (method == PNG_FILTER_TYPE_BASE)
1065 switch (filters & (PNG_ALL_FILTERS | 0x07))
1069 case 7: png_warning(png_ptr, "Unknown row filter for method 0");
1070 case PNG_FILTER_VALUE_NONE: png_ptr->do_filter=PNG_FILTER_NONE; break;
1071 case PNG_FILTER_VALUE_SUB: png_ptr->do_filter=PNG_FILTER_SUB; break;
1072 case PNG_FILTER_VALUE_UP: png_ptr->do_filter=PNG_FILTER_UP; break;
1073 case PNG_FILTER_VALUE_AVG: png_ptr->do_filter=PNG_FILTER_AVG; break;
1074 case PNG_FILTER_VALUE_PAETH: png_ptr->do_filter=PNG_FILTER_PAETH;break;
1075 default: png_ptr->do_filter = (png_byte)filters; break;
1078 /* If we have allocated the row_buf, this means we have already started
1079 * with the image and we should have allocated all of the filter buffers
1080 * that have been selected. If prev_row isn't already allocated, then
1081 * it is too late to start using the filters that need it, since we
1082 * will be missing the data in the previous row. If an application
1083 * wants to start and stop using particular filters during compression,
1084 * it should start out with all of the filters, and then add and
1085 * remove them after the start of compression.
1087 if (png_ptr->row_buf != NULL)
1089 if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
1091 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1092 (png_ptr->rowbytes + 1));
1093 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1096 if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
1098 if (png_ptr->prev_row == NULL)
1100 png_warning(png_ptr, "Can't add Up filter after starting");
1101 png_ptr->do_filter &= ~PNG_FILTER_UP;
1105 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1106 (png_ptr->rowbytes + 1));
1107 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1111 if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
1113 if (png_ptr->prev_row == NULL)
1115 png_warning(png_ptr, "Can't add Average filter after starting");
1116 png_ptr->do_filter &= ~PNG_FILTER_AVG;
1120 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1121 (png_ptr->rowbytes + 1));
1122 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1126 if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
1127 png_ptr->paeth_row == NULL)
1129 if (png_ptr->prev_row == NULL)
1131 png_warning(png_ptr, "Can't add Paeth filter after starting");
1132 png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
1136 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1137 (png_ptr->rowbytes + 1));
1138 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1142 if (png_ptr->do_filter == PNG_NO_FILTERS)
1143 png_ptr->do_filter = PNG_FILTER_NONE;
1147 png_error(png_ptr, "Unknown custom filter method");
1150 /* This allows us to influence the way in which libpng chooses the "best"
1151 * filter for the current scanline. While the "minimum-sum-of-absolute-
1152 * differences metric is relatively fast and effective, there is some
1153 * question as to whether it can be improved upon by trying to keep the
1154 * filtered data going to zlib more consistent, hopefully resulting in
1155 * better compression.
1157 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* GRR 970116 */
1159 png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,
1160 int num_weights, png_doublep filter_weights,
1161 png_doublep filter_costs)
1165 png_debug(1, "in png_set_filter_heuristics\n");
1166 if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)
1168 png_warning(png_ptr, "Unknown filter heuristic method");
1172 if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT)
1174 heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
1177 if (num_weights < 0 || filter_weights == NULL ||
1178 heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
1183 png_ptr->num_prev_filters = (png_byte)num_weights;
1184 png_ptr->heuristic_method = (png_byte)heuristic_method;
1186 if (num_weights > 0)
1188 if (png_ptr->prev_filters == NULL)
1190 png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
1191 (png_uint_32)(sizeof(png_byte) * num_weights));
1193 /* To make sure that the weighting starts out fairly */
1194 for (i = 0; i < num_weights; i++)
1196 png_ptr->prev_filters[i] = 255;
1200 if (png_ptr->filter_weights == NULL)
1202 png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
1203 (png_uint_32)(sizeof(png_uint_16) * num_weights));
1205 png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
1206 (png_uint_32)(sizeof(png_uint_16) * num_weights));
1207 for (i = 0; i < num_weights; i++)
1209 png_ptr->inv_filter_weights[i] =
1210 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1214 for (i = 0; i < num_weights; i++)
1216 if (filter_weights[i] < 0.0)
1218 png_ptr->inv_filter_weights[i] =
1219 png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
1223 png_ptr->inv_filter_weights[i] =
1224 (png_uint_16)((double)PNG_WEIGHT_FACTOR*filter_weights[i]+0.5);
1225 png_ptr->filter_weights[i] =
1226 (png_uint_16)((double)PNG_WEIGHT_FACTOR/filter_weights[i]+0.5);
1231 /* If, in the future, there are other filter methods, this would
1232 * need to be based on png_ptr->filter.
1234 if (png_ptr->filter_costs == NULL)
1236 png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
1237 (png_uint_32)(sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
1239 png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
1240 (png_uint_32)(sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
1242 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
1244 png_ptr->inv_filter_costs[i] =
1245 png_ptr->filter_costs[i] = PNG_COST_FACTOR;
1249 /* Here is where we set the relative costs of the different filters. We
1250 * should take the desired compression level into account when setting
1251 * the costs, so that Paeth, for instance, has a high relative cost at low
1252 * compression levels, while it has a lower relative cost at higher
1253 * compression settings. The filter types are in order of increasing
1254 * relative cost, so it would be possible to do this with an algorithm.
1256 for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
1258 if (filter_costs == NULL || filter_costs[i] < 0.0)
1260 png_ptr->inv_filter_costs[i] =
1261 png_ptr->filter_costs[i] = PNG_COST_FACTOR;
1263 else if (filter_costs[i] >= 1.0)
1265 png_ptr->inv_filter_costs[i] =
1266 (png_uint_16)((double)PNG_COST_FACTOR / filter_costs[i] + 0.5);
1267 png_ptr->filter_costs[i] =
1268 (png_uint_16)((double)PNG_COST_FACTOR * filter_costs[i] + 0.5);
1272 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1275 png_set_compression_level(png_structp png_ptr, int level)
1277 png_debug(1, "in png_set_compression_level\n");
1278 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
1279 png_ptr->zlib_level = level;
1283 png_set_compression_mem_level(png_structp png_ptr, int mem_level)
1285 png_debug(1, "in png_set_compression_mem_level\n");
1286 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
1287 png_ptr->zlib_mem_level = mem_level;
1291 png_set_compression_strategy(png_structp png_ptr, int strategy)
1293 png_debug(1, "in png_set_compression_strategy\n");
1294 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
1295 png_ptr->zlib_strategy = strategy;
1299 png_set_compression_window_bits(png_structp png_ptr, int window_bits)
1301 if (window_bits > 15)
1302 png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
1303 else if (window_bits < 8)
1304 png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
1306 /* avoid libpng bug with 256-byte windows */
1307 if (window_bits == 8)
1309 png_warning(png_ptr, "Compression window is being reset to 512");
1313 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;
1314 png_ptr->zlib_window_bits = window_bits;
1318 png_set_compression_method(png_structp png_ptr, int method)
1320 png_debug(1, "in png_set_compression_method\n");
1322 png_warning(png_ptr, "Only compression method 8 is supported by PNG");
1323 png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
1324 png_ptr->zlib_method = method;
1328 png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
1330 png_ptr->write_row_fn = write_row_fn;
1333 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
1335 png_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
1336 write_user_transform_fn)
1338 png_debug(1, "in png_set_write_user_transform_fn\n");
1339 png_ptr->transformations |= PNG_USER_TRANSFORM;
1340 png_ptr->write_user_transform_fn = write_user_transform_fn;
1345 #if defined(PNG_INFO_IMAGE_SUPPORTED)
1347 png_write_png(png_structp png_ptr, png_infop info_ptr,
1348 int transforms, voidp params)
1350 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
1351 /* invert the alpha channel from opacity to transparency */
1352 if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
1353 png_set_invert_alpha(png_ptr);
1356 /* Write the file header information. */
1357 png_write_info(png_ptr, info_ptr);
1359 /* ------ these transformations don't touch the info structure ------- */
1361 #if defined(PNG_WRITE_INVERT_SUPPORTED)
1362 /* invert monochrome pixels */
1363 if (transforms & PNG_TRANSFORM_INVERT_MONO)
1364 png_set_invert_mono(png_ptr);
1367 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
1368 /* Shift the pixels up to a legal bit depth and fill in
1369 * as appropriate to correctly scale the image.
1371 if ((transforms & PNG_TRANSFORM_SHIFT)
1372 && (info_ptr->valid & PNG_INFO_sBIT))
1373 png_set_shift(png_ptr, &info_ptr->sig_bit);
1376 #if defined(PNG_WRITE_PACK_SUPPORTED)
1377 /* pack pixels into bytes */
1378 if (transforms & PNG_TRANSFORM_PACKING)
1379 png_set_packing(png_ptr);
1382 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
1383 /* swap location of alpha bytes from ARGB to RGBA */
1384 if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
1385 png_set_swap_alpha(png_ptr);
1388 #if defined(PNG_WRITE_FILLER_SUPPORTED)
1389 /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
1390 * RGB (4 channels -> 3 channels). The second parameter is not used.
1392 if (transforms & PNG_TRANSFORM_STRIP_FILLER)
1393 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
1396 #if defined(PNG_WRITE_BGR_SUPPORTED)
1397 /* flip BGR pixels to RGB */
1398 if (transforms & PNG_TRANSFORM_BGR)
1399 png_set_bgr(png_ptr);
1402 #if defined(PNG_WRITE_SWAP_SUPPORTED)
1403 /* swap bytes of 16-bit files to most significant byte first */
1404 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
1405 png_set_swap(png_ptr);
1408 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
1409 /* swap bits of 1, 2, 4 bit packed pixel formats */
1410 if (transforms & PNG_TRANSFORM_PACKSWAP)
1411 png_set_packswap(png_ptr);
1414 /* ----------------------- end of transformations ------------------- */
1416 /* write the bits */
1417 if (info_ptr->valid & PNG_INFO_IDAT)
1418 png_write_image(png_ptr, info_ptr->row_pointers);
1420 /* It is REQUIRED to call this to finish writing the rest of the file */
1421 png_write_end(png_ptr, info_ptr);
1423 if(transforms == 0 || params == NULL)
1424 /* quiet compiler warnings */ return;
1427 #endif /* PNG_WRITE_SUPPORTED */