2 /* pngwutil.c - utilities to write a PNG file
4 * libpng 1.2.5 - October 3, 2002
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2002 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.)
13 #ifdef PNG_WRITE_SUPPORTED
15 /* Place a 32-bit number into a buffer in PNG byte order. We work
16 * with unsigned numbers for convenience, although one supported
17 * ancillary chunk uses signed (two's complement) numbers.
20 png_save_uint_32(png_bytep buf, png_uint_32 i)
22 buf[0] = (png_byte)((i >> 24) & 0xff);
23 buf[1] = (png_byte)((i >> 16) & 0xff);
24 buf[2] = (png_byte)((i >> 8) & 0xff);
25 buf[3] = (png_byte)(i & 0xff);
28 #if defined(PNG_WRITE_pCAL_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
29 /* The png_save_int_32 function assumes integers are stored in two's
30 * complement format. If this isn't the case, then this routine needs to
31 * be modified to write data in two's complement format.
34 png_save_int_32(png_bytep buf, png_int_32 i)
36 buf[0] = (png_byte)((i >> 24) & 0xff);
37 buf[1] = (png_byte)((i >> 16) & 0xff);
38 buf[2] = (png_byte)((i >> 8) & 0xff);
39 buf[3] = (png_byte)(i & 0xff);
43 /* Place a 16-bit number into a buffer in PNG byte order.
44 * The parameter is declared unsigned int, not png_uint_16,
45 * just to avoid potential problems on pre-ANSI C compilers.
48 png_save_uint_16(png_bytep buf, unsigned int i)
50 buf[0] = (png_byte)((i >> 8) & 0xff);
51 buf[1] = (png_byte)(i & 0xff);
54 /* Write a PNG chunk all at once. The type is an array of ASCII characters
55 * representing the chunk name. The array must be at least 4 bytes in
56 * length, and does not need to be null terminated. To be safe, pass the
57 * pre-defined chunk names here, and if you need a new one, define it
58 * where the others are defined. The length is the length of the data.
59 * All the data must be present. If that is not possible, use the
60 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
64 png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
65 png_bytep data, png_size_t length)
67 png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
68 png_write_chunk_data(png_ptr, data, length);
69 png_write_chunk_end(png_ptr);
72 /* Write the start of a PNG chunk. The type is the chunk type.
73 * The total_length is the sum of the lengths of all the data you will be
74 * passing in png_write_chunk_data().
77 png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
81 png_debug2(0, "Writing %s chunk (%lu bytes)\n", chunk_name, length);
83 /* write the length */
84 png_save_uint_32(buf, length);
85 png_write_data(png_ptr, buf, (png_size_t)4);
87 /* write the chunk name */
88 png_write_data(png_ptr, chunk_name, (png_size_t)4);
89 /* reset the crc and run it over the chunk name */
90 png_reset_crc(png_ptr);
91 png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
94 /* Write the data of a PNG chunk started with png_write_chunk_start().
95 * Note that multiple calls to this function are allowed, and that the
96 * sum of the lengths from these calls *must* add up to the total_length
97 * given to png_write_chunk_start().
100 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
102 /* write the data, and run the CRC over it */
103 if (data != NULL && length > 0)
105 png_calculate_crc(png_ptr, data, length);
106 png_write_data(png_ptr, data, length);
110 /* Finish a chunk started with png_write_chunk_start(). */
112 png_write_chunk_end(png_structp png_ptr)
117 png_save_uint_32(buf, png_ptr->crc);
119 png_write_data(png_ptr, buf, (png_size_t)4);
122 /* Simple function to write the signature. If we have already written
123 * the magic bytes of the signature, or more likely, the PNG stream is
124 * being embedded into another stream and doesn't need its own signature,
125 * we should call png_set_sig_bytes() to tell libpng how many of the
126 * bytes have already been written.
129 png_write_sig(png_structp png_ptr)
131 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
132 /* write the rest of the 8 byte signature */
133 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
134 (png_size_t)8 - png_ptr->sig_bytes);
135 if(png_ptr->sig_bytes < 3)
136 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
139 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
141 * This pair of functions encapsulates the operation of (a) compressing a
142 * text string, and (b) issuing it later as a series of chunk data writes.
143 * The compression_state structure is shared context for these functions
144 * set up by the caller in order to make the whole mess thread-safe.
149 char *input; /* the uncompressed input data */
150 int input_len; /* its length */
151 int num_output_ptr; /* number of output pointers used */
152 int max_output_ptr; /* size of output_ptr */
153 png_charpp output_ptr; /* array of pointers to output */
156 /* compress given text into storage in the png_ptr structure */
157 static int /* PRIVATE */
158 png_text_compress(png_structp png_ptr,
159 png_charp text, png_size_t text_len, int compression,
160 compression_state *comp)
164 comp->num_output_ptr = comp->max_output_ptr = 0;
165 comp->output_ptr = NULL;
168 /* we may just want to pass the text right through */
169 if (compression == PNG_TEXT_COMPRESSION_NONE)
172 comp->input_len = text_len;
173 return((int)text_len);
176 if (compression >= PNG_TEXT_COMPRESSION_LAST)
178 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
180 sprintf(msg, "Unknown compression type %d", compression);
181 png_warning(png_ptr, msg);
183 png_warning(png_ptr, "Unknown compression type");
187 /* We can't write the chunk until we find out how much data we have,
188 * which means we need to run the compressor first and save the
189 * output. This shouldn't be a problem, as the vast majority of
190 * comments should be reasonable, but we will set up an array of
191 * malloc'd pointers to be sure.
193 * If we knew the application was well behaved, we could simplify this
194 * greatly by assuming we can always malloc an output buffer large
195 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
196 * and malloc this directly. The only time this would be a bad idea is
197 * if we can't malloc more than 64K and we have 64K of random input
198 * data, or if the input string is incredibly large (although this
199 * wouldn't cause a failure, just a slowdown due to swapping).
202 /* set up the compression buffers */
203 png_ptr->zstream.avail_in = (uInt)text_len;
204 png_ptr->zstream.next_in = (Bytef *)text;
205 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
206 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
208 /* this is the same compression loop as in png_write_row() */
211 /* compress the data */
212 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
216 if (png_ptr->zstream.msg != NULL)
217 png_error(png_ptr, png_ptr->zstream.msg);
219 png_error(png_ptr, "zlib error");
221 /* check to see if we need more room */
222 if (!png_ptr->zstream.avail_out && png_ptr->zstream.avail_in)
224 /* make sure the output array has room */
225 if (comp->num_output_ptr >= comp->max_output_ptr)
229 old_max = comp->max_output_ptr;
230 comp->max_output_ptr = comp->num_output_ptr + 4;
231 if (comp->output_ptr != NULL)
235 old_ptr = comp->output_ptr;
236 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
237 (png_uint_32)(comp->max_output_ptr * sizeof (png_charpp)));
238 png_memcpy(comp->output_ptr, old_ptr, old_max
239 * sizeof (png_charp));
240 png_free(png_ptr, old_ptr);
243 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
244 (png_uint_32)(comp->max_output_ptr * sizeof (png_charp)));
248 comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr,
249 (png_uint_32)png_ptr->zbuf_size);
250 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
252 comp->num_output_ptr++;
254 /* and reset the buffer */
255 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
256 png_ptr->zstream.next_out = png_ptr->zbuf;
258 /* continue until we don't have any more to compress */
259 } while (png_ptr->zstream.avail_in);
261 /* finish the compression */
264 /* tell zlib we are finished */
265 ret = deflate(&png_ptr->zstream, Z_FINISH);
269 /* check to see if we need more room */
270 if (!(png_ptr->zstream.avail_out))
272 /* check to make sure our output array has room */
273 if (comp->num_output_ptr >= comp->max_output_ptr)
277 old_max = comp->max_output_ptr;
278 comp->max_output_ptr = comp->num_output_ptr + 4;
279 if (comp->output_ptr != NULL)
283 old_ptr = comp->output_ptr;
284 /* This could be optimized to realloc() */
285 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
286 (png_uint_32)(comp->max_output_ptr * sizeof (png_charpp)));
287 png_memcpy(comp->output_ptr, old_ptr,
288 old_max * sizeof (png_charp));
289 png_free(png_ptr, old_ptr);
292 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
293 (png_uint_32)(comp->max_output_ptr * sizeof (png_charp)));
296 /* save off the data */
297 comp->output_ptr[comp->num_output_ptr] =
298 (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size);
299 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
301 comp->num_output_ptr++;
303 /* and reset the buffer pointers */
304 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
305 png_ptr->zstream.next_out = png_ptr->zbuf;
308 else if (ret != Z_STREAM_END)
310 /* we got an error */
311 if (png_ptr->zstream.msg != NULL)
312 png_error(png_ptr, png_ptr->zstream.msg);
314 png_error(png_ptr, "zlib error");
316 } while (ret != Z_STREAM_END);
318 /* text length is number of buffers plus last buffer */
319 text_len = png_ptr->zbuf_size * comp->num_output_ptr;
320 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
321 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
323 return((int)text_len);
326 /* ship the compressed text out via chunk writes */
327 static void /* PRIVATE */
328 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
332 /* handle the no-compression case */
335 png_write_chunk_data(png_ptr, (png_bytep)comp->input,
336 (png_size_t)comp->input_len);
340 /* write saved output buffers, if any */
341 for (i = 0; i < comp->num_output_ptr; i++)
343 png_write_chunk_data(png_ptr,(png_bytep)comp->output_ptr[i],
345 png_free(png_ptr, comp->output_ptr[i]);
346 comp->output_ptr[i]=NULL;
348 if (comp->max_output_ptr != 0)
349 png_free(png_ptr, comp->output_ptr);
350 comp->output_ptr=NULL;
351 /* write anything left in zbuf */
352 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
353 png_write_chunk_data(png_ptr, png_ptr->zbuf,
354 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
356 /* reset zlib for another zTXt/iTXt or the image data */
357 deflateReset(&png_ptr->zstream);
362 /* Write the IHDR chunk, and update the png_struct with the necessary
363 * information. Note that the rest of this code depends upon this
364 * information being correct.
367 png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
368 int bit_depth, int color_type, int compression_type, int filter_type,
371 #ifdef PNG_USE_LOCAL_ARRAYS
374 png_byte buf[13]; /* buffer to store the IHDR info */
376 png_debug(1, "in png_write_IHDR\n");
377 /* Check that we have valid input data from the application info */
380 case PNG_COLOR_TYPE_GRAY:
387 case 16: png_ptr->channels = 1; break;
388 default: png_error(png_ptr,"Invalid bit depth for grayscale image");
391 case PNG_COLOR_TYPE_RGB:
392 if (bit_depth != 8 && bit_depth != 16)
393 png_error(png_ptr, "Invalid bit depth for RGB image");
394 png_ptr->channels = 3;
396 case PNG_COLOR_TYPE_PALETTE:
402 case 8: png_ptr->channels = 1; break;
403 default: png_error(png_ptr, "Invalid bit depth for paletted image");
406 case PNG_COLOR_TYPE_GRAY_ALPHA:
407 if (bit_depth != 8 && bit_depth != 16)
408 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
409 png_ptr->channels = 2;
411 case PNG_COLOR_TYPE_RGB_ALPHA:
412 if (bit_depth != 8 && bit_depth != 16)
413 png_error(png_ptr, "Invalid bit depth for RGBA image");
414 png_ptr->channels = 4;
417 png_error(png_ptr, "Invalid image color type specified");
420 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
422 png_warning(png_ptr, "Invalid compression type specified");
423 compression_type = PNG_COMPRESSION_TYPE_BASE;
426 /* Write filter_method 64 (intrapixel differencing) only if
427 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
428 * 2. Libpng did not write a PNG signature (this filter_method is only
429 * used in PNG datastreams that are embedded in MNG datastreams) and
430 * 3. The application called png_permit_mng_features with a mask that
431 * included PNG_FLAG_MNG_FILTER_64 and
432 * 4. The filter_method is 64 and
433 * 5. The color_type is RGB or RGBA
436 #if defined(PNG_MNG_FEATURES_SUPPORTED)
437 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
438 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
439 (color_type == PNG_COLOR_TYPE_RGB ||
440 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
441 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
443 filter_type != PNG_FILTER_TYPE_BASE)
445 png_warning(png_ptr, "Invalid filter type specified");
446 filter_type = PNG_FILTER_TYPE_BASE;
449 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
450 if (interlace_type != PNG_INTERLACE_NONE &&
451 interlace_type != PNG_INTERLACE_ADAM7)
453 png_warning(png_ptr, "Invalid interlace type specified");
454 interlace_type = PNG_INTERLACE_ADAM7;
457 interlace_type=PNG_INTERLACE_NONE;
460 /* save off the relevent information */
461 png_ptr->bit_depth = (png_byte)bit_depth;
462 png_ptr->color_type = (png_byte)color_type;
463 png_ptr->interlaced = (png_byte)interlace_type;
464 #if defined(PNG_MNG_FEATURES_SUPPORTED)
465 png_ptr->filter_type = (png_byte)filter_type;
467 png_ptr->width = width;
468 png_ptr->height = height;
470 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
471 png_ptr->rowbytes = ((width * (png_size_t)png_ptr->pixel_depth + 7) >> 3);
472 /* set the usr info, so any transformations can modify it */
473 png_ptr->usr_width = png_ptr->width;
474 png_ptr->usr_bit_depth = png_ptr->bit_depth;
475 png_ptr->usr_channels = png_ptr->channels;
477 /* pack the header information into the buffer */
478 png_save_uint_32(buf, width);
479 png_save_uint_32(buf + 4, height);
480 buf[8] = (png_byte)bit_depth;
481 buf[9] = (png_byte)color_type;
482 buf[10] = (png_byte)compression_type;
483 buf[11] = (png_byte)filter_type;
484 buf[12] = (png_byte)interlace_type;
486 /* write the chunk */
487 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
489 /* initialize zlib with PNG info */
490 png_ptr->zstream.zalloc = png_zalloc;
491 png_ptr->zstream.zfree = png_zfree;
492 png_ptr->zstream.opaque = (voidpf)png_ptr;
493 if (!(png_ptr->do_filter))
495 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
496 png_ptr->bit_depth < 8)
497 png_ptr->do_filter = PNG_FILTER_NONE;
499 png_ptr->do_filter = PNG_ALL_FILTERS;
501 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
503 if (png_ptr->do_filter != PNG_FILTER_NONE)
504 png_ptr->zlib_strategy = Z_FILTERED;
506 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
508 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
509 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
510 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
511 png_ptr->zlib_mem_level = 8;
512 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
513 png_ptr->zlib_window_bits = 15;
514 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
515 png_ptr->zlib_method = 8;
516 deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
517 png_ptr->zlib_method, png_ptr->zlib_window_bits,
518 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
519 png_ptr->zstream.next_out = png_ptr->zbuf;
520 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
522 png_ptr->mode = PNG_HAVE_IHDR;
525 /* write the palette. We are careful not to trust png_color to be in the
526 * correct order for PNG, so people can redefine it to any convenient
530 png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
532 #ifdef PNG_USE_LOCAL_ARRAYS
539 png_debug(1, "in png_write_PLTE\n");
541 #if defined(PNG_MNG_FEATURES_SUPPORTED)
542 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
544 num_pal == 0) || num_pal > 256)
546 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
548 png_error(png_ptr, "Invalid number of colors in palette");
552 png_warning(png_ptr, "Invalid number of colors in palette");
557 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
560 "Ignoring request to write a PLTE chunk in grayscale PNG");
564 png_ptr->num_palette = (png_uint_16)num_pal;
565 png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);
567 png_write_chunk_start(png_ptr, (png_bytep)png_PLTE, num_pal * 3);
568 #ifndef PNG_NO_POINTER_INDEXING
569 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
571 buf[0] = pal_ptr->red;
572 buf[1] = pal_ptr->green;
573 buf[2] = pal_ptr->blue;
574 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
577 /* This is a little slower but some buggy compilers need to do this instead */
579 for (i = 0; i < num_pal; i++)
581 buf[0] = pal_ptr[i].red;
582 buf[1] = pal_ptr[i].green;
583 buf[2] = pal_ptr[i].blue;
584 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
587 png_write_chunk_end(png_ptr);
588 png_ptr->mode |= PNG_HAVE_PLTE;
591 /* write an IDAT chunk */
593 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
595 #ifdef PNG_USE_LOCAL_ARRAYS
598 png_debug(1, "in png_write_IDAT\n");
599 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
600 png_ptr->mode |= PNG_HAVE_IDAT;
603 /* write an IEND chunk */
605 png_write_IEND(png_structp png_ptr)
607 #ifdef PNG_USE_LOCAL_ARRAYS
610 png_debug(1, "in png_write_IEND\n");
611 png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
613 png_ptr->mode |= PNG_HAVE_IEND;
616 #if defined(PNG_WRITE_gAMA_SUPPORTED)
617 /* write a gAMA chunk */
618 #ifdef PNG_FLOATING_POINT_SUPPORTED
620 png_write_gAMA(png_structp png_ptr, double file_gamma)
622 #ifdef PNG_USE_LOCAL_ARRAYS
628 png_debug(1, "in png_write_gAMA\n");
629 /* file_gamma is saved in 1/100,000ths */
630 igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
631 png_save_uint_32(buf, igamma);
632 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
635 #ifdef PNG_FIXED_POINT_SUPPORTED
637 png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
639 #ifdef PNG_USE_LOCAL_ARRAYS
644 png_debug(1, "in png_write_gAMA\n");
645 /* file_gamma is saved in 1/100,000ths */
646 png_save_uint_32(buf, (png_uint_32)file_gamma);
647 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
652 #if defined(PNG_WRITE_sRGB_SUPPORTED)
653 /* write a sRGB chunk */
655 png_write_sRGB(png_structp png_ptr, int srgb_intent)
657 #ifdef PNG_USE_LOCAL_ARRAYS
662 png_debug(1, "in png_write_sRGB\n");
663 if(srgb_intent >= PNG_sRGB_INTENT_LAST)
665 "Invalid sRGB rendering intent specified");
666 buf[0]=(png_byte)srgb_intent;
667 png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
671 #if defined(PNG_WRITE_iCCP_SUPPORTED)
672 /* write an iCCP chunk */
674 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
675 png_charp profile, int profile_len)
677 #ifdef PNG_USE_LOCAL_ARRAYS
682 compression_state comp;
684 png_debug(1, "in png_write_iCCP\n");
685 if (name == NULL || (name_len = png_check_keyword(png_ptr, name,
688 png_warning(png_ptr, "Empty keyword in iCCP chunk");
692 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
693 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
699 profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len,
700 PNG_COMPRESSION_TYPE_BASE, &comp);
702 /* make sure we include the NULL after the name and the compression type */
703 png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
704 (png_uint_32)name_len+profile_len+2);
705 new_name[name_len+1]=0x00;
706 png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 2);
709 png_write_compressed_data_out(png_ptr, &comp);
711 png_write_chunk_end(png_ptr);
712 png_free(png_ptr, new_name);
716 #if defined(PNG_WRITE_sPLT_SUPPORTED)
717 /* write a sPLT chunk */
719 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
721 #ifdef PNG_USE_LOCAL_ARRAYS
726 png_byte entrybuf[10];
727 int entry_size = (spalette->depth == 8 ? 6 : 10);
728 int palette_size = entry_size * spalette->nentries;
730 #ifdef PNG_NO_POINTER_INDEXING
734 png_debug(1, "in png_write_sPLT\n");
735 if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr,
736 spalette->name, &new_name))==0)
738 png_warning(png_ptr, "Empty keyword in sPLT chunk");
742 /* make sure we include the NULL after the name */
743 png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
744 (png_uint_32)(name_len + 2 + palette_size));
745 png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 1);
746 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, 1);
748 /* loop through each palette entry, writing appropriately */
749 #ifndef PNG_NO_POINTER_INDEXING
750 for (ep = spalette->entries; ep<spalette->entries+spalette->nentries; ep++)
752 if (spalette->depth == 8)
754 entrybuf[0] = (png_byte)ep->red;
755 entrybuf[1] = (png_byte)ep->green;
756 entrybuf[2] = (png_byte)ep->blue;
757 entrybuf[3] = (png_byte)ep->alpha;
758 png_save_uint_16(entrybuf + 4, ep->frequency);
762 png_save_uint_16(entrybuf + 0, ep->red);
763 png_save_uint_16(entrybuf + 2, ep->green);
764 png_save_uint_16(entrybuf + 4, ep->blue);
765 png_save_uint_16(entrybuf + 6, ep->alpha);
766 png_save_uint_16(entrybuf + 8, ep->frequency);
768 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
771 ep=spalette->entries;
772 for (i=0; i>spalette->nentries; i++)
774 if (spalette->depth == 8)
776 entrybuf[0] = (png_byte)ep[i].red;
777 entrybuf[1] = (png_byte)ep[i].green;
778 entrybuf[2] = (png_byte)ep[i].blue;
779 entrybuf[3] = (png_byte)ep[i].alpha;
780 png_save_uint_16(entrybuf + 4, ep[i].frequency);
784 png_save_uint_16(entrybuf + 0, ep[i].red);
785 png_save_uint_16(entrybuf + 2, ep[i].green);
786 png_save_uint_16(entrybuf + 4, ep[i].blue);
787 png_save_uint_16(entrybuf + 6, ep[i].alpha);
788 png_save_uint_16(entrybuf + 8, ep[i].frequency);
790 png_write_chunk_data(png_ptr, entrybuf, entry_size);
794 png_write_chunk_end(png_ptr);
795 png_free(png_ptr, new_name);
799 #if defined(PNG_WRITE_sBIT_SUPPORTED)
800 /* write the sBIT chunk */
802 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
804 #ifdef PNG_USE_LOCAL_ARRAYS
810 png_debug(1, "in png_write_sBIT\n");
811 /* make sure we don't depend upon the order of PNG_COLOR_8 */
812 if (color_type & PNG_COLOR_MASK_COLOR)
816 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
817 png_ptr->usr_bit_depth);
818 if (sbit->red == 0 || sbit->red > maxbits ||
819 sbit->green == 0 || sbit->green > maxbits ||
820 sbit->blue == 0 || sbit->blue > maxbits)
822 png_warning(png_ptr, "Invalid sBIT depth specified");
826 buf[1] = sbit->green;
832 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
834 png_warning(png_ptr, "Invalid sBIT depth specified");
841 if (color_type & PNG_COLOR_MASK_ALPHA)
843 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
845 png_warning(png_ptr, "Invalid sBIT depth specified");
848 buf[size++] = sbit->alpha;
851 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
855 #if defined(PNG_WRITE_cHRM_SUPPORTED)
856 /* write the cHRM chunk */
857 #ifdef PNG_FLOATING_POINT_SUPPORTED
859 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
860 double red_x, double red_y, double green_x, double green_y,
861 double blue_x, double blue_y)
863 #ifdef PNG_USE_LOCAL_ARRAYS
869 png_debug(1, "in png_write_cHRM\n");
870 /* each value is saved in 1/100,000ths */
871 if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
872 white_x + white_y > 1.0)
874 png_warning(png_ptr, "Invalid cHRM white point specified");
875 #if !defined(PNG_NO_CONSOLE_IO)
876 fprintf(stderr,"white_x=%f, white_y=%f\n",white_x, white_y);
880 itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
881 png_save_uint_32(buf, itemp);
882 itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
883 png_save_uint_32(buf + 4, itemp);
885 if (red_x < 0 || red_x > 0.8 || red_y < 0 || red_y > 0.8 ||
888 png_warning(png_ptr, "Invalid cHRM red point specified");
891 itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
892 png_save_uint_32(buf + 8, itemp);
893 itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
894 png_save_uint_32(buf + 12, itemp);
896 if (green_x < 0 || green_x > 0.8 || green_y < 0 || green_y > 0.8 ||
897 green_x + green_y > 1.0)
899 png_warning(png_ptr, "Invalid cHRM green point specified");
902 itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
903 png_save_uint_32(buf + 16, itemp);
904 itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
905 png_save_uint_32(buf + 20, itemp);
907 if (blue_x < 0 || blue_x > 0.8 || blue_y < 0 || blue_y > 0.8 ||
908 blue_x + blue_y > 1.0)
910 png_warning(png_ptr, "Invalid cHRM blue point specified");
913 itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
914 png_save_uint_32(buf + 24, itemp);
915 itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
916 png_save_uint_32(buf + 28, itemp);
918 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
921 #ifdef PNG_FIXED_POINT_SUPPORTED
923 png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
924 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
925 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
926 png_fixed_point blue_y)
928 #ifdef PNG_USE_LOCAL_ARRAYS
933 png_debug(1, "in png_write_cHRM\n");
934 /* each value is saved in 1/100,000ths */
935 if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L)
937 png_warning(png_ptr, "Invalid fixed cHRM white point specified");
938 #if !defined(PNG_NO_CONSOLE_IO)
939 fprintf(stderr,"white_x=%ld, white_y=%ld\n",white_x, white_y);
943 png_save_uint_32(buf, (png_uint_32)white_x);
944 png_save_uint_32(buf + 4, (png_uint_32)white_y);
946 if (red_x > 80000L || red_y > 80000L || red_x + red_y > 100000L)
948 png_warning(png_ptr, "Invalid cHRM fixed red point specified");
951 png_save_uint_32(buf + 8, (png_uint_32)red_x);
952 png_save_uint_32(buf + 12, (png_uint_32)red_y);
954 if (green_x > 80000L || green_y > 80000L || green_x + green_y > 100000L)
956 png_warning(png_ptr, "Invalid fixed cHRM green point specified");
959 png_save_uint_32(buf + 16, (png_uint_32)green_x);
960 png_save_uint_32(buf + 20, (png_uint_32)green_y);
962 if (blue_x > 80000L || blue_y > 80000L || blue_x + blue_y > 100000L)
964 png_warning(png_ptr, "Invalid fixed cHRM blue point specified");
967 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
968 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
970 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
975 #if defined(PNG_WRITE_tRNS_SUPPORTED)
976 /* write the tRNS chunk */
978 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
979 int num_trans, int color_type)
981 #ifdef PNG_USE_LOCAL_ARRAYS
986 png_debug(1, "in png_write_tRNS\n");
987 if (color_type == PNG_COLOR_TYPE_PALETTE)
989 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
991 png_warning(png_ptr,"Invalid number of transparent colors specified");
994 /* write the chunk out as it is */
995 png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans, (png_size_t)num_trans);
997 else if (color_type == PNG_COLOR_TYPE_GRAY)
999 /* one 16 bit value */
1000 if(tran->gray >= (1 << png_ptr->bit_depth))
1002 png_warning(png_ptr,
1003 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1006 png_save_uint_16(buf, tran->gray);
1007 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
1009 else if (color_type == PNG_COLOR_TYPE_RGB)
1011 /* three 16 bit values */
1012 png_save_uint_16(buf, tran->red);
1013 png_save_uint_16(buf + 2, tran->green);
1014 png_save_uint_16(buf + 4, tran->blue);
1015 if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1017 png_warning(png_ptr,
1018 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1021 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
1025 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1030 #if defined(PNG_WRITE_bKGD_SUPPORTED)
1031 /* write the background chunk */
1033 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1035 #ifdef PNG_USE_LOCAL_ARRAYS
1040 png_debug(1, "in png_write_bKGD\n");
1041 if (color_type == PNG_COLOR_TYPE_PALETTE)
1044 #if defined(PNG_MNG_FEATURES_SUPPORTED)
1045 (png_ptr->num_palette ||
1046 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
1048 back->index > png_ptr->num_palette)
1050 png_warning(png_ptr, "Invalid background palette index");
1053 buf[0] = back->index;
1054 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
1056 else if (color_type & PNG_COLOR_MASK_COLOR)
1058 png_save_uint_16(buf, back->red);
1059 png_save_uint_16(buf + 2, back->green);
1060 png_save_uint_16(buf + 4, back->blue);
1061 if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1063 png_warning(png_ptr,
1064 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1067 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
1071 if(back->gray >= (1 << png_ptr->bit_depth))
1073 png_warning(png_ptr,
1074 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1077 png_save_uint_16(buf, back->gray);
1078 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
1083 #if defined(PNG_WRITE_hIST_SUPPORTED)
1084 /* write the histogram */
1086 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
1088 #ifdef PNG_USE_LOCAL_ARRAYS
1094 png_debug(1, "in png_write_hIST\n");
1095 if (num_hist > (int)png_ptr->num_palette)
1097 png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
1098 png_ptr->num_palette);
1099 png_warning(png_ptr, "Invalid number of histogram entries specified");
1103 png_write_chunk_start(png_ptr, (png_bytep)png_hIST, (png_uint_32)(num_hist * 2));
1104 for (i = 0; i < num_hist; i++)
1106 png_save_uint_16(buf, hist[i]);
1107 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1109 png_write_chunk_end(png_ptr);
1113 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1114 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1115 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1116 * and if invalid, correct the keyword rather than discarding the entire
1117 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1118 * length, forbids leading or trailing whitespace, multiple internal spaces,
1119 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1121 * The new_key is allocated to hold the corrected keyword and must be freed
1122 * by the calling routine. This avoids problems with trying to write to
1123 * static keywords without having to have duplicate copies of the strings.
1125 png_size_t /* PRIVATE */
1126 png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1133 png_debug(1, "in png_check_keyword\n");
1136 if (key == NULL || (key_len = png_strlen(key)) == 0)
1138 png_warning(png_ptr, "zero length keyword");
1139 return ((png_size_t)0);
1142 png_debug1(2, "Keyword to be checked is '%s'\n", key);
1144 *new_key = (png_charp)png_malloc(png_ptr, (png_uint_32)(key_len + 2));
1146 /* Replace non-printing characters with a blank and print a warning */
1147 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1149 if (*kp < 0x20 || (*kp > 0x7E && (png_byte)*kp < 0xA1))
1151 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
1154 sprintf(msg, "invalid keyword character 0x%02X", *kp);
1155 png_warning(png_ptr, msg);
1157 png_warning(png_ptr, "invalid character in keyword");
1168 /* Remove any trailing white space. */
1169 kp = *new_key + key_len - 1;
1172 png_warning(png_ptr, "trailing spaces removed from keyword");
1181 /* Remove any leading white space. */
1185 png_warning(png_ptr, "leading spaces removed from keyword");
1194 png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);
1196 /* Remove multiple internal spaces. */
1197 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1199 if (*kp == ' ' && kflag == 0)
1204 else if (*kp == ' ')
1217 png_warning(png_ptr, "extra interior spaces removed from keyword");
1221 png_free(png_ptr, *new_key);
1223 png_warning(png_ptr, "Zero length keyword");
1228 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1237 #if defined(PNG_WRITE_tEXt_SUPPORTED)
1238 /* write a tEXt chunk */
1240 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1241 png_size_t text_len)
1243 #ifdef PNG_USE_LOCAL_ARRAYS
1249 png_debug(1, "in png_write_tEXt\n");
1250 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1252 png_warning(png_ptr, "Empty keyword in tEXt chunk");
1256 if (text == NULL || *text == '\0')
1259 text_len = png_strlen(text);
1261 /* make sure we include the 0 after the key */
1262 png_write_chunk_start(png_ptr, (png_bytep)png_tEXt, (png_uint_32)key_len+text_len+1);
1264 * We leave it to the application to meet PNG-1.0 requirements on the
1265 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1266 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1267 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1269 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1271 png_write_chunk_data(png_ptr, (png_bytep)text, text_len);
1273 png_write_chunk_end(png_ptr);
1274 png_free(png_ptr, new_key);
1278 #if defined(PNG_WRITE_zTXt_SUPPORTED)
1279 /* write a compressed text chunk */
1281 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
1282 png_size_t text_len, int compression)
1284 #ifdef PNG_USE_LOCAL_ARRAYS
1290 compression_state comp;
1292 png_debug(1, "in png_write_zTXt\n");
1294 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1296 png_warning(png_ptr, "Empty keyword in zTXt chunk");
1300 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1302 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1303 png_free(png_ptr, new_key);
1307 text_len = png_strlen(text);
1309 png_free(png_ptr, new_key);
1311 /* compute the compressed data; do it now for the length */
1312 text_len = png_text_compress(png_ptr, text, text_len, compression,
1315 /* write start of chunk */
1316 png_write_chunk_start(png_ptr, (png_bytep)png_zTXt, (png_uint_32)
1317 (key_len+text_len+2));
1319 png_write_chunk_data(png_ptr, (png_bytep)key, key_len + 1);
1320 buf[0] = (png_byte)compression;
1321 /* write compression */
1322 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1323 /* write the compressed data */
1324 png_write_compressed_data_out(png_ptr, &comp);
1326 /* close the chunk */
1327 png_write_chunk_end(png_ptr);
1331 #if defined(PNG_WRITE_iTXt_SUPPORTED)
1332 /* write an iTXt chunk */
1334 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1335 png_charp lang, png_charp lang_key, png_charp text)
1337 #ifdef PNG_USE_LOCAL_ARRAYS
1340 png_size_t lang_len, key_len, lang_key_len, text_len;
1341 png_charp new_lang, new_key;
1343 compression_state comp;
1345 png_debug(1, "in png_write_iTXt\n");
1347 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1349 png_warning(png_ptr, "Empty keyword in iTXt chunk");
1352 if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1354 png_warning(png_ptr, "Empty language field in iTXt chunk");
1359 if (lang_key == NULL)
1362 lang_key_len = png_strlen(lang_key);
1367 text_len = png_strlen(text);
1369 /* compute the compressed data; do it now for the length */
1370 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1374 /* make sure we include the compression flag, the compression byte,
1375 * and the NULs after the key, lang, and lang_key parts */
1377 png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
1379 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1386 * We leave it to the application to meet PNG-1.0 requirements on the
1387 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1388 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1389 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1391 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1393 /* set the compression flag */
1394 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1395 compression == PNG_TEXT_COMPRESSION_NONE)
1397 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1399 /* set the compression method */
1401 png_write_chunk_data(png_ptr, cbuf, 2);
1404 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf), lang_len + 1);
1405 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf), lang_key_len + 1);
1406 png_write_compressed_data_out(png_ptr, &comp);
1408 png_write_chunk_end(png_ptr);
1409 png_free(png_ptr, new_key);
1411 png_free(png_ptr, new_lang);
1415 #if defined(PNG_WRITE_oFFs_SUPPORTED)
1416 /* write the oFFs chunk */
1418 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1421 #ifdef PNG_USE_LOCAL_ARRAYS
1426 png_debug(1, "in png_write_oFFs\n");
1427 if (unit_type >= PNG_OFFSET_LAST)
1428 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1430 png_save_int_32(buf, x_offset);
1431 png_save_int_32(buf + 4, y_offset);
1432 buf[8] = (png_byte)unit_type;
1434 png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
1438 #if defined(PNG_WRITE_pCAL_SUPPORTED)
1439 /* write the pCAL chunk (described in the PNG extensions document) */
1441 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1442 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1444 #ifdef PNG_USE_LOCAL_ARRAYS
1447 png_size_t purpose_len, units_len, total_len;
1448 png_uint_32p params_len;
1450 png_charp new_purpose;
1453 png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams);
1454 if (type >= PNG_EQUATION_LAST)
1455 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1457 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1458 png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len);
1459 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1460 png_debug1(3, "pCAL units length = %d\n", (int)units_len);
1461 total_len = purpose_len + units_len + 10;
1463 params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams
1464 *sizeof(png_uint_32)));
1466 /* Find the length of each parameter, making sure we don't count the
1467 null terminator for the last parameter. */
1468 for (i = 0; i < nparams; i++)
1470 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1471 png_debug2(3, "pCAL parameter %d length = %lu\n", i, params_len[i]);
1472 total_len += (png_size_t)params_len[i];
1475 png_debug1(3, "pCAL total length = %d\n", (int)total_len);
1476 png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
1477 png_write_chunk_data(png_ptr, (png_bytep)new_purpose, purpose_len);
1478 png_save_int_32(buf, X0);
1479 png_save_int_32(buf + 4, X1);
1480 buf[8] = (png_byte)type;
1481 buf[9] = (png_byte)nparams;
1482 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1483 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1485 png_free(png_ptr, new_purpose);
1487 for (i = 0; i < nparams; i++)
1489 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1490 (png_size_t)params_len[i]);
1493 png_free(png_ptr, params_len);
1494 png_write_chunk_end(png_ptr);
1498 #if defined(PNG_WRITE_sCAL_SUPPORTED)
1499 /* write the sCAL chunk */
1500 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
1502 png_write_sCAL(png_structp png_ptr, int unit, double width,double height)
1504 #ifdef PNG_USE_LOCAL_ARRAYS
1507 png_size_t total_len;
1508 char wbuf[32], hbuf[32];
1510 png_debug(1, "in png_write_sCAL\n");
1512 #if defined(_WIN32_WCE)
1513 /* sprintf() function is not supported on WindowsCE */
1516 swprintf(wc_buf, TEXT("%12.12e"), width);
1517 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, wbuf, 32, NULL, NULL);
1518 swprintf(wc_buf, TEXT("%12.12e"), height);
1519 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, hbuf, 32, NULL, NULL);
1522 sprintf(wbuf, "%12.12e", width);
1523 sprintf(hbuf, "%12.12e", height);
1525 total_len = 1 + png_strlen(wbuf)+1 + png_strlen(hbuf);
1527 png_debug1(3, "sCAL total length = %d\n", (int)total_len);
1528 png_write_chunk_start(png_ptr, (png_bytep)png_sCAL, (png_uint_32)total_len);
1529 png_write_chunk_data(png_ptr, (png_bytep)&unit, 1);
1530 png_write_chunk_data(png_ptr, (png_bytep)wbuf, png_strlen(wbuf)+1);
1531 png_write_chunk_data(png_ptr, (png_bytep)hbuf, png_strlen(hbuf));
1533 png_write_chunk_end(png_ptr);
1536 #ifdef PNG_FIXED_POINT_SUPPORTED
1538 png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
1541 #ifdef PNG_USE_LOCAL_ARRAYS
1544 png_size_t total_len;
1545 char wbuf[32], hbuf[32];
1547 png_debug(1, "in png_write_sCAL_s\n");
1549 png_strcpy(wbuf,(const char *)width);
1550 png_strcpy(hbuf,(const char *)height);
1551 total_len = 1 + png_strlen(wbuf)+1 + png_strlen(hbuf);
1553 png_debug1(3, "sCAL total length = %d\n", total_len);
1554 png_write_chunk_start(png_ptr, (png_bytep)png_sCAL, (png_uint_32)total_len);
1555 png_write_chunk_data(png_ptr, (png_bytep)&unit, 1);
1556 png_write_chunk_data(png_ptr, (png_bytep)wbuf, png_strlen(wbuf)+1);
1557 png_write_chunk_data(png_ptr, (png_bytep)hbuf, png_strlen(hbuf));
1559 png_write_chunk_end(png_ptr);
1565 #if defined(PNG_WRITE_pHYs_SUPPORTED)
1566 /* write the pHYs chunk */
1568 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
1569 png_uint_32 y_pixels_per_unit,
1572 #ifdef PNG_USE_LOCAL_ARRAYS
1577 png_debug(1, "in png_write_pHYs\n");
1578 if (unit_type >= PNG_RESOLUTION_LAST)
1579 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1581 png_save_uint_32(buf, x_pixels_per_unit);
1582 png_save_uint_32(buf + 4, y_pixels_per_unit);
1583 buf[8] = (png_byte)unit_type;
1585 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
1589 #if defined(PNG_WRITE_tIME_SUPPORTED)
1590 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1591 * or png_convert_from_time_t(), or fill in the structure yourself.
1594 png_write_tIME(png_structp png_ptr, png_timep mod_time)
1596 #ifdef PNG_USE_LOCAL_ARRAYS
1601 png_debug(1, "in png_write_tIME\n");
1602 if (mod_time->month > 12 || mod_time->month < 1 ||
1603 mod_time->day > 31 || mod_time->day < 1 ||
1604 mod_time->hour > 23 || mod_time->second > 60)
1606 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1610 png_save_uint_16(buf, mod_time->year);
1611 buf[2] = mod_time->month;
1612 buf[3] = mod_time->day;
1613 buf[4] = mod_time->hour;
1614 buf[5] = mod_time->minute;
1615 buf[6] = mod_time->second;
1617 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
1621 /* initializes the row writing capability of libpng */
1623 png_write_start_row(png_structp png_ptr)
1625 #ifdef PNG_USE_LOCAL_ARRAYS
1626 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1628 /* start of interlace block */
1629 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1631 /* offset to next interlace block */
1632 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1634 /* start of interlace block in the y direction */
1635 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1637 /* offset to next interlace block in the y direction */
1638 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1641 png_size_t buf_size;
1643 png_debug(1, "in png_write_start_row\n");
1644 buf_size = (png_size_t)(((png_ptr->width * png_ptr->usr_channels *
1645 png_ptr->usr_bit_depth + 7) >> 3) + 1);
1647 /* set up row buffer */
1648 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
1649 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1651 /* set up filtering buffer, if using this filter */
1652 if (png_ptr->do_filter & PNG_FILTER_SUB)
1654 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1655 (png_ptr->rowbytes + 1));
1656 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1659 /* We only need to keep the previous row if we are using one of these. */
1660 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1662 /* set up previous row buffer */
1663 png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
1664 png_memset(png_ptr->prev_row, 0, buf_size);
1666 if (png_ptr->do_filter & PNG_FILTER_UP)
1668 png_ptr->up_row = (png_bytep )png_malloc(png_ptr,
1669 (png_ptr->rowbytes + 1));
1670 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1673 if (png_ptr->do_filter & PNG_FILTER_AVG)
1675 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1676 (png_ptr->rowbytes + 1));
1677 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1680 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1682 png_ptr->paeth_row = (png_bytep )png_malloc(png_ptr,
1683 (png_ptr->rowbytes + 1));
1684 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1688 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1689 /* if interlaced, we need to set up width and height of pass */
1690 if (png_ptr->interlaced)
1692 if (!(png_ptr->transformations & PNG_INTERLACE))
1694 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1695 png_pass_ystart[0]) / png_pass_yinc[0];
1696 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1697 png_pass_start[0]) / png_pass_inc[0];
1701 png_ptr->num_rows = png_ptr->height;
1702 png_ptr->usr_width = png_ptr->width;
1708 png_ptr->num_rows = png_ptr->height;
1709 png_ptr->usr_width = png_ptr->width;
1711 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1712 png_ptr->zstream.next_out = png_ptr->zbuf;
1715 /* Internal use only. Called when finished processing a row of data. */
1717 png_write_finish_row(png_structp png_ptr)
1719 #ifdef PNG_USE_LOCAL_ARRAYS
1720 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1722 /* start of interlace block */
1723 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1725 /* offset to next interlace block */
1726 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1728 /* start of interlace block in the y direction */
1729 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1731 /* offset to next interlace block in the y direction */
1732 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1737 png_debug(1, "in png_write_finish_row\n");
1739 png_ptr->row_number++;
1741 /* see if we are done */
1742 if (png_ptr->row_number < png_ptr->num_rows)
1745 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1746 /* if interlaced, go to next pass */
1747 if (png_ptr->interlaced)
1749 png_ptr->row_number = 0;
1750 if (png_ptr->transformations & PNG_INTERLACE)
1756 /* loop until we find a non-zero width or height pass */
1760 if (png_ptr->pass >= 7)
1762 png_ptr->usr_width = (png_ptr->width +
1763 png_pass_inc[png_ptr->pass] - 1 -
1764 png_pass_start[png_ptr->pass]) /
1765 png_pass_inc[png_ptr->pass];
1766 png_ptr->num_rows = (png_ptr->height +
1767 png_pass_yinc[png_ptr->pass] - 1 -
1768 png_pass_ystart[png_ptr->pass]) /
1769 png_pass_yinc[png_ptr->pass];
1770 if (png_ptr->transformations & PNG_INTERLACE)
1772 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1776 /* reset the row above the image for the next pass */
1777 if (png_ptr->pass < 7)
1779 if (png_ptr->prev_row != NULL)
1780 png_memset(png_ptr->prev_row, 0,
1781 (png_size_t) (((png_uint_32)png_ptr->usr_channels *
1782 (png_uint_32)png_ptr->usr_bit_depth *
1783 png_ptr->width + 7) >> 3) + 1);
1789 /* if we get here, we've just written the last row, so we need
1790 to flush the compressor */
1793 /* tell the compressor we are done */
1794 ret = deflate(&png_ptr->zstream, Z_FINISH);
1795 /* check for an error */
1798 /* check to see if we need more room */
1799 if (!(png_ptr->zstream.avail_out))
1801 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1802 png_ptr->zstream.next_out = png_ptr->zbuf;
1803 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1806 else if (ret != Z_STREAM_END)
1808 if (png_ptr->zstream.msg != NULL)
1809 png_error(png_ptr, png_ptr->zstream.msg);
1811 png_error(png_ptr, "zlib error");
1813 } while (ret != Z_STREAM_END);
1815 /* write any extra space */
1816 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1818 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1819 png_ptr->zstream.avail_out);
1822 deflateReset(&png_ptr->zstream);
1825 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
1826 /* Pick out the correct pixels for the interlace pass.
1827 * The basic idea here is to go through the row with a source
1828 * pointer and a destination pointer (sp and dp), and copy the
1829 * correct pixels for the pass. As the row gets compacted,
1830 * sp will always be >= dp, so we should never overwrite anything.
1831 * See the default: case for the easiest code to understand.
1834 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1836 #ifdef PNG_USE_LOCAL_ARRAYS
1837 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1839 /* start of interlace block */
1840 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1842 /* offset to next interlace block */
1843 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1846 png_debug(1, "in png_do_write_interlace\n");
1847 /* we don't have to do anything on the last pass (6) */
1848 #if defined(PNG_USELESS_TESTS_SUPPORTED)
1849 if (row != NULL && row_info != NULL && pass < 6)
1854 /* each pixel depth is handled separately */
1855 switch (row_info->pixel_depth)
1865 png_uint_32 row_width = row_info->width;
1870 for (i = png_pass_start[pass]; i < row_width;
1871 i += png_pass_inc[pass])
1873 sp = row + (png_size_t)(i >> 3);
1874 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
1875 d |= (value << shift);
1880 *dp++ = (png_byte)d;
1899 png_uint_32 row_width = row_info->width;
1904 for (i = png_pass_start[pass]; i < row_width;
1905 i += png_pass_inc[pass])
1907 sp = row + (png_size_t)(i >> 2);
1908 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
1909 d |= (value << shift);
1914 *dp++ = (png_byte)d;
1932 png_uint_32 row_width = row_info->width;
1937 for (i = png_pass_start[pass]; i < row_width;
1938 i += png_pass_inc[pass])
1940 sp = row + (png_size_t)(i >> 1);
1941 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
1942 d |= (value << shift);
1947 *dp++ = (png_byte)d;
1962 png_uint_32 row_width = row_info->width;
1963 png_size_t pixel_bytes;
1965 /* start at the beginning */
1967 /* find out how many bytes each pixel takes up */
1968 pixel_bytes = (row_info->pixel_depth >> 3);
1969 /* loop through the row, only looking at the pixels that
1971 for (i = png_pass_start[pass]; i < row_width;
1972 i += png_pass_inc[pass])
1974 /* find out where the original pixel is */
1975 sp = row + (png_size_t)i * pixel_bytes;
1976 /* move the pixel */
1978 png_memcpy(dp, sp, pixel_bytes);
1985 /* set new row width */
1986 row_info->width = (row_info->width +
1987 png_pass_inc[pass] - 1 -
1988 png_pass_start[pass]) /
1990 row_info->rowbytes = ((row_info->width *
1991 row_info->pixel_depth + 7) >> 3);
1996 /* This filters the row, chooses which filter to use, if it has not already
1997 * been specified by the application, and then writes the row out with the
2000 #define PNG_MAXSUM (~((png_uint_32)0) >> 1)
2001 #define PNG_HISHIFT 10
2002 #define PNG_LOMASK ((png_uint_32)0xffffL)
2003 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2005 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2007 png_bytep prev_row, best_row, row_buf;
2008 png_uint_32 mins, bpp;
2009 png_byte filter_to_do = png_ptr->do_filter;
2010 png_uint_32 row_bytes = row_info->rowbytes;
2011 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2012 int num_p_filters = (int)png_ptr->num_prev_filters;
2015 png_debug(1, "in png_write_find_filter\n");
2016 /* find out how many bytes offset each pixel is */
2017 bpp = (row_info->pixel_depth + 7) / 8;
2019 prev_row = png_ptr->prev_row;
2020 best_row = row_buf = png_ptr->row_buf;
2023 /* The prediction method we use is to find which method provides the
2024 * smallest value when summing the absolute values of the distances
2025 * from zero, using anything >= 128 as negative numbers. This is known
2026 * as the "minimum sum of absolute differences" heuristic. Other
2027 * heuristics are the "weighted minimum sum of absolute differences"
2028 * (experimental and can in theory improve compression), and the "zlib
2029 * predictive" method (not implemented yet), which does test compressions
2030 * of lines using different filter methods, and then chooses the
2031 * (series of) filter(s) that give minimum compressed data size (VERY
2032 * computationally expensive).
2034 * GRR 980525: consider also
2035 * (1) minimum sum of absolute differences from running average (i.e.,
2036 * keep running sum of non-absolute differences & count of bytes)
2037 * [track dispersion, too? restart average if dispersion too large?]
2038 * (1b) minimum sum of absolute differences from sliding average, probably
2039 * with window size <= deflate window (usually 32K)
2040 * (2) minimum sum of squared differences from zero or running average
2041 * (i.e., ~ root-mean-square approach)
2045 /* We don't need to test the 'no filter' case if this is the only filter
2046 * that has been chosen, as it doesn't actually do anything to the data.
2048 if ((filter_to_do & PNG_FILTER_NONE) &&
2049 filter_to_do != PNG_FILTER_NONE)
2052 png_uint_32 sum = 0;
2056 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2059 sum += (v < 128) ? v : 256 - v;
2062 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2063 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2065 png_uint_32 sumhi, sumlo;
2067 sumlo = sum & PNG_LOMASK;
2068 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
2070 /* Reduce the sum if we match any of the previous rows */
2071 for (j = 0; j < num_p_filters; j++)
2073 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2075 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2077 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2082 /* Factor in the cost of this filter (this is here for completeness,
2083 * but it makes no sense to have a "cost" for the NONE filter, as
2084 * it has the minimum possible computational cost - none).
2086 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2088 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2091 if (sumhi > PNG_HIMASK)
2094 sum = (sumhi << PNG_HISHIFT) + sumlo;
2101 if (filter_to_do == PNG_FILTER_SUB)
2102 /* it's the only filter so no testing is needed */
2104 png_bytep rp, lp, dp;
2106 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2111 for (lp = row_buf + 1; i < row_bytes;
2112 i++, rp++, lp++, dp++)
2114 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2116 best_row = png_ptr->sub_row;
2119 else if (filter_to_do & PNG_FILTER_SUB)
2121 png_bytep rp, dp, lp;
2122 png_uint_32 sum = 0, lmins = mins;
2126 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2127 /* We temporarily increase the "minimum sum" by the factor we
2128 * would reduce the sum of this filter, so that we can do the
2129 * early exit comparison without scaling the sum each time.
2131 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2134 png_uint_32 lmhi, lmlo;
2135 lmlo = lmins & PNG_LOMASK;
2136 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2138 for (j = 0; j < num_p_filters; j++)
2140 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2142 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2144 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2149 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2151 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2154 if (lmhi > PNG_HIMASK)
2157 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2161 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2166 sum += (v < 128) ? v : 256 - v;
2168 for (lp = row_buf + 1; i < row_info->rowbytes;
2169 i++, rp++, lp++, dp++)
2171 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2173 sum += (v < 128) ? v : 256 - v;
2175 if (sum > lmins) /* We are already worse, don't continue. */
2179 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2180 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2183 png_uint_32 sumhi, sumlo;
2184 sumlo = sum & PNG_LOMASK;
2185 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2187 for (j = 0; j < num_p_filters; j++)
2189 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2191 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
2193 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
2198 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2200 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2203 if (sumhi > PNG_HIMASK)
2206 sum = (sumhi << PNG_HISHIFT) + sumlo;
2213 best_row = png_ptr->sub_row;
2218 if (filter_to_do == PNG_FILTER_UP)
2220 png_bytep rp, dp, pp;
2223 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2224 pp = prev_row + 1; i < row_bytes;
2225 i++, rp++, pp++, dp++)
2227 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2229 best_row = png_ptr->up_row;
2232 else if (filter_to_do & PNG_FILTER_UP)
2234 png_bytep rp, dp, pp;
2235 png_uint_32 sum = 0, lmins = mins;
2240 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2241 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2244 png_uint_32 lmhi, lmlo;
2245 lmlo = lmins & PNG_LOMASK;
2246 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2248 for (j = 0; j < num_p_filters; j++)
2250 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2252 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2254 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2259 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2261 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2264 if (lmhi > PNG_HIMASK)
2267 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2271 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2272 pp = prev_row + 1; i < row_bytes; i++)
2274 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2276 sum += (v < 128) ? v : 256 - v;
2278 if (sum > lmins) /* We are already worse, don't continue. */
2282 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2283 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2286 png_uint_32 sumhi, sumlo;
2287 sumlo = sum & PNG_LOMASK;
2288 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2290 for (j = 0; j < num_p_filters; j++)
2292 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2294 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2296 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2301 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2303 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2306 if (sumhi > PNG_HIMASK)
2309 sum = (sumhi << PNG_HISHIFT) + sumlo;
2316 best_row = png_ptr->up_row;
2321 if (filter_to_do == PNG_FILTER_AVG)
2323 png_bytep rp, dp, pp, lp;
2325 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2326 pp = prev_row + 1; i < bpp; i++)
2328 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2330 for (lp = row_buf + 1; i < row_bytes; i++)
2332 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2335 best_row = png_ptr->avg_row;
2338 else if (filter_to_do & PNG_FILTER_AVG)
2340 png_bytep rp, dp, pp, lp;
2341 png_uint_32 sum = 0, lmins = mins;
2345 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2346 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2349 png_uint_32 lmhi, lmlo;
2350 lmlo = lmins & PNG_LOMASK;
2351 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2353 for (j = 0; j < num_p_filters; j++)
2355 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
2357 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2359 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2364 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2366 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2369 if (lmhi > PNG_HIMASK)
2372 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2376 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2377 pp = prev_row + 1; i < bpp; i++)
2379 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2381 sum += (v < 128) ? v : 256 - v;
2383 for (lp = row_buf + 1; i < row_bytes; i++)
2386 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
2388 sum += (v < 128) ? v : 256 - v;
2390 if (sum > lmins) /* We are already worse, don't continue. */
2394 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2395 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2398 png_uint_32 sumhi, sumlo;
2399 sumlo = sum & PNG_LOMASK;
2400 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2402 for (j = 0; j < num_p_filters; j++)
2404 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2406 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2408 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2413 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2415 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2418 if (sumhi > PNG_HIMASK)
2421 sum = (sumhi << PNG_HISHIFT) + sumlo;
2428 best_row = png_ptr->avg_row;
2433 if (filter_to_do == PNG_FILTER_PAETH)
2435 png_bytep rp, dp, pp, cp, lp;
2437 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2438 pp = prev_row + 1; i < bpp; i++)
2440 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2443 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2445 int a, b, c, pa, pb, pc, p;
2459 pa = p < 0 ? -p : p;
2460 pb = pc < 0 ? -pc : pc;
2461 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2464 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2466 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2468 best_row = png_ptr->paeth_row;
2471 else if (filter_to_do & PNG_FILTER_PAETH)
2473 png_bytep rp, dp, pp, cp, lp;
2474 png_uint_32 sum = 0, lmins = mins;
2478 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2479 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2482 png_uint_32 lmhi, lmlo;
2483 lmlo = lmins & PNG_LOMASK;
2484 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2486 for (j = 0; j < num_p_filters; j++)
2488 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2490 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2492 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2497 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2499 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2502 if (lmhi > PNG_HIMASK)
2505 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2509 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2510 pp = prev_row + 1; i < bpp; i++)
2512 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2514 sum += (v < 128) ? v : 256 - v;
2517 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2519 int a, b, c, pa, pb, pc, p;
2525 #ifndef PNG_SLOW_PAETH
2533 pa = p < 0 ? -p : p;
2534 pb = pc < 0 ? -pc : pc;
2535 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2537 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2538 #else /* PNG_SLOW_PAETH */
2543 if (pa <= pb && pa <= pc)
2549 #endif /* PNG_SLOW_PAETH */
2551 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2553 sum += (v < 128) ? v : 256 - v;
2555 if (sum > lmins) /* We are already worse, don't continue. */
2559 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2560 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2563 png_uint_32 sumhi, sumlo;
2564 sumlo = sum & PNG_LOMASK;
2565 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2567 for (j = 0; j < num_p_filters; j++)
2569 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2571 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2573 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2578 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2580 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2583 if (sumhi > PNG_HIMASK)
2586 sum = (sumhi << PNG_HISHIFT) + sumlo;
2592 best_row = png_ptr->paeth_row;
2596 /* Do the actual writing of the filtered row data from the chosen filter. */
2598 png_write_filtered_row(png_ptr, best_row);
2600 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2601 /* Save the type of filter we picked this time for future calculations */
2602 if (png_ptr->num_prev_filters > 0)
2605 for (j = 1; j < num_p_filters; j++)
2607 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
2609 png_ptr->prev_filters[j] = best_row[0];
2615 /* Do the actual writing of a previously filtered row. */
2617 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2619 png_debug(1, "in png_write_filtered_row\n");
2620 png_debug1(2, "filter = %d\n", filtered_row[0]);
2621 /* set up the zlib input buffer */
2623 png_ptr->zstream.next_in = filtered_row;
2624 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2625 /* repeat until we have compressed all the data */
2628 int ret; /* return of zlib */
2630 /* compress the data */
2631 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2632 /* check for compression errors */
2635 if (png_ptr->zstream.msg != NULL)
2636 png_error(png_ptr, png_ptr->zstream.msg);
2638 png_error(png_ptr, "zlib error");
2641 /* see if it is time to write another IDAT */
2642 if (!(png_ptr->zstream.avail_out))
2644 /* write the IDAT and reset the zlib output buffer */
2645 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2646 png_ptr->zstream.next_out = png_ptr->zbuf;
2647 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2649 /* repeat until all data has been compressed */
2650 } while (png_ptr->zstream.avail_in);
2652 /* swap the current and previous rows */
2653 if (png_ptr->prev_row != NULL)
2657 tptr = png_ptr->prev_row;
2658 png_ptr->prev_row = png_ptr->row_buf;
2659 png_ptr->row_buf = tptr;
2662 /* finish row - updates counters and flushes zlib if last row */
2663 png_write_finish_row(png_ptr);
2665 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
2666 png_ptr->flush_rows++;
2668 if (png_ptr->flush_dist > 0 &&
2669 png_ptr->flush_rows >= png_ptr->flush_dist)
2671 png_write_flush(png_ptr);
2675 #endif /* PNG_WRITE_SUPPORTED */