2 /* pngwutil.c - utilities to write a PNG file
4 * Last changed in libpng 1.4.1 [February 25, 2010]
5 * Copyright (c) 1998-2010 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
14 #define PNG_NO_PEDANTIC_WARNINGS
16 #ifdef PNG_WRITE_SUPPORTED
19 /* Place a 32-bit number into a buffer in PNG byte order. We work
20 * with unsigned numbers for convenience, although one supported
21 * ancillary chunk uses signed (two's complement) numbers.
24 png_save_uint_32(png_bytep buf, png_uint_32 i)
26 buf[0] = (png_byte)((i >> 24) & 0xff);
27 buf[1] = (png_byte)((i >> 16) & 0xff);
28 buf[2] = (png_byte)((i >> 8) & 0xff);
29 buf[3] = (png_byte)(i & 0xff);
32 #ifdef PNG_SAVE_INT_32_SUPPORTED
33 /* The png_save_int_32 function assumes integers are stored in two's
34 * complement format. If this isn't the case, then this routine needs to
35 * be modified to write data in two's complement format.
38 png_save_int_32(png_bytep buf, png_int_32 i)
40 buf[0] = (png_byte)((i >> 24) & 0xff);
41 buf[1] = (png_byte)((i >> 16) & 0xff);
42 buf[2] = (png_byte)((i >> 8) & 0xff);
43 buf[3] = (png_byte)(i & 0xff);
47 /* Place a 16-bit number into a buffer in PNG byte order.
48 * The parameter is declared unsigned int, not png_uint_16,
49 * just to avoid potential problems on pre-ANSI C compilers.
52 png_save_uint_16(png_bytep buf, unsigned int i)
54 buf[0] = (png_byte)((i >> 8) & 0xff);
55 buf[1] = (png_byte)(i & 0xff);
58 /* Simple function to write the signature. If we have already written
59 * the magic bytes of the signature, or more likely, the PNG stream is
60 * being embedded into another stream and doesn't need its own signature,
61 * we should call png_set_sig_bytes() to tell libpng how many of the
62 * bytes have already been written.
65 png_write_sig(png_structp png_ptr)
67 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
69 #ifdef PNG_IO_STATE_SUPPORTED
70 /* Inform the I/O callback that the signature is being written */
71 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
74 /* Write the rest of the 8 byte signature */
75 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
76 (png_size_t)(8 - png_ptr->sig_bytes));
77 if (png_ptr->sig_bytes < 3)
78 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
81 /* Write a PNG chunk all at once. The type is an array of ASCII characters
82 * representing the chunk name. The array must be at least 4 bytes in
83 * length, and does not need to be null terminated. To be safe, pass the
84 * pre-defined chunk names here, and if you need a new one, define it
85 * where the others are defined. The length is the length of the data.
86 * All the data must be present. If that is not possible, use the
87 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
91 png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
92 png_bytep data, png_size_t length)
96 png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
97 png_write_chunk_data(png_ptr, data, (png_size_t)length);
98 png_write_chunk_end(png_ptr);
101 /* Write the start of a PNG chunk. The type is the chunk type.
102 * The total_length is the sum of the lengths of all the data you will be
103 * passing in png_write_chunk_data().
106 png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
111 png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
112 (unsigned long)length);
117 #ifdef PNG_IO_STATE_SUPPORTED
118 /* Inform the I/O callback that the chunk header is being written.
119 * PNG_IO_CHUNK_HDR requires a single I/O call.
121 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
124 /* Write the length and the chunk name */
125 png_save_uint_32(buf, length);
126 png_memcpy(buf + 4, chunk_name, 4);
127 png_write_data(png_ptr, buf, (png_size_t)8);
128 /* Put the chunk name into png_ptr->chunk_name */
129 png_memcpy(png_ptr->chunk_name, chunk_name, 4);
130 /* Reset the crc and run it over the chunk name */
131 png_reset_crc(png_ptr);
132 png_calculate_crc(png_ptr, chunk_name, 4);
134 #ifdef PNG_IO_STATE_SUPPORTED
135 /* Inform the I/O callback that chunk data will (possibly) be written.
136 * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
138 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
142 /* Write the data of a PNG chunk started with png_write_chunk_start().
143 * Note that multiple calls to this function are allowed, and that the
144 * sum of the lengths from these calls *must* add up to the total_length
145 * given to png_write_chunk_start().
148 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
150 /* Write the data, and run the CRC over it */
153 if (data != NULL && length > 0)
155 png_write_data(png_ptr, data, length);
156 /* Update the CRC after writing the data,
157 * in case that the user I/O routine alters it.
159 png_calculate_crc(png_ptr, data, length);
163 /* Finish a chunk started with png_write_chunk_start(). */
165 png_write_chunk_end(png_structp png_ptr)
169 if (png_ptr == NULL) return;
171 #ifdef PNG_IO_STATE_SUPPORTED
172 /* Inform the I/O callback that the chunk CRC is being written.
173 * PNG_IO_CHUNK_CRC requires a single I/O function call.
175 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
178 /* Write the crc in a single operation */
179 png_save_uint_32(buf, png_ptr->crc);
181 png_write_data(png_ptr, buf, (png_size_t)4);
184 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
185 /* This pair of functions encapsulates the operation of (a) compressing a
186 * text string, and (b) issuing it later as a series of chunk data writes.
187 * The compression_state structure is shared context for these functions
188 * set up by the caller in order to make the whole mess thread-safe.
193 char *input; /* The uncompressed input data */
194 int input_len; /* Its length */
195 int num_output_ptr; /* Number of output pointers used */
196 int max_output_ptr; /* Size of output_ptr */
197 png_charpp output_ptr; /* Array of pointers to output */
200 /* Compress given text into storage in the png_ptr structure */
201 static int /* PRIVATE */
202 png_text_compress(png_structp png_ptr,
203 png_charp text, png_size_t text_len, int compression,
204 compression_state *comp)
208 comp->num_output_ptr = 0;
209 comp->max_output_ptr = 0;
210 comp->output_ptr = NULL;
214 /* We may just want to pass the text right through */
215 if (compression == PNG_TEXT_COMPRESSION_NONE)
218 comp->input_len = text_len;
219 return((int)text_len);
222 if (compression >= PNG_TEXT_COMPRESSION_LAST)
224 #ifdef PNG_STDIO_SUPPORTED
226 png_snprintf(msg, 50, "Unknown compression type %d", compression);
227 png_warning(png_ptr, msg);
229 png_warning(png_ptr, "Unknown compression type");
233 /* We can't write the chunk until we find out how much data we have,
234 * which means we need to run the compressor first and save the
235 * output. This shouldn't be a problem, as the vast majority of
236 * comments should be reasonable, but we will set up an array of
237 * malloc'd pointers to be sure.
239 * If we knew the application was well behaved, we could simplify this
240 * greatly by assuming we can always malloc an output buffer large
241 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
242 * and malloc this directly. The only time this would be a bad idea is
243 * if we can't malloc more than 64K and we have 64K of random input
244 * data, or if the input string is incredibly large (although this
245 * wouldn't cause a failure, just a slowdown due to swapping).
248 /* Set up the compression buffers */
249 png_ptr->zstream.avail_in = (uInt)text_len;
250 png_ptr->zstream.next_in = (Bytef *)text;
251 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
252 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
254 /* This is the same compression loop as in png_write_row() */
257 /* Compress the data */
258 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
262 if (png_ptr->zstream.msg != NULL)
263 png_error(png_ptr, png_ptr->zstream.msg);
265 png_error(png_ptr, "zlib error");
267 /* Check to see if we need more room */
268 if (!(png_ptr->zstream.avail_out))
270 /* Make sure the output array has room */
271 if (comp->num_output_ptr >= comp->max_output_ptr)
275 old_max = comp->max_output_ptr;
276 comp->max_output_ptr = comp->num_output_ptr + 4;
277 if (comp->output_ptr != NULL)
281 old_ptr = comp->output_ptr;
282 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
284 (comp->max_output_ptr * png_sizeof(png_charpp)));
285 png_memcpy(comp->output_ptr, old_ptr, old_max
286 * png_sizeof(png_charp));
287 png_free(png_ptr, old_ptr);
290 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
292 (comp->max_output_ptr * png_sizeof(png_charp)));
296 comp->output_ptr[comp->num_output_ptr] =
297 (png_charp)png_malloc(png_ptr,
298 (png_alloc_size_t)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 */
304 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
305 png_ptr->zstream.next_out = png_ptr->zbuf;
307 /* Continue until we don't have any more to compress */
308 } while (png_ptr->zstream.avail_in);
310 /* Finish the compression */
313 /* Tell zlib we are finished */
314 ret = deflate(&png_ptr->zstream, Z_FINISH);
318 /* Check to see if we need more room */
319 if (!(png_ptr->zstream.avail_out))
321 /* Check to make sure our output array has room */
322 if (comp->num_output_ptr >= comp->max_output_ptr)
326 old_max = comp->max_output_ptr;
327 comp->max_output_ptr = comp->num_output_ptr + 4;
328 if (comp->output_ptr != NULL)
332 old_ptr = comp->output_ptr;
333 /* This could be optimized to realloc() */
334 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
335 (png_alloc_size_t)(comp->max_output_ptr *
336 png_sizeof(png_charp)));
337 png_memcpy(comp->output_ptr, old_ptr,
338 old_max * png_sizeof(png_charp));
339 png_free(png_ptr, old_ptr);
342 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
343 (png_alloc_size_t)(comp->max_output_ptr *
344 png_sizeof(png_charp)));
348 comp->output_ptr[comp->num_output_ptr] =
349 (png_charp)png_malloc(png_ptr,
350 (png_alloc_size_t)png_ptr->zbuf_size);
351 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
353 comp->num_output_ptr++;
355 /* and reset the buffer pointers */
356 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
357 png_ptr->zstream.next_out = png_ptr->zbuf;
360 else if (ret != Z_STREAM_END)
362 /* We got an error */
363 if (png_ptr->zstream.msg != NULL)
364 png_error(png_ptr, png_ptr->zstream.msg);
366 png_error(png_ptr, "zlib error");
368 } while (ret != Z_STREAM_END);
370 /* Text length is number of buffers plus last buffer */
371 text_len = png_ptr->zbuf_size * comp->num_output_ptr;
372 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
373 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
375 return((int)text_len);
378 /* Ship the compressed text out via chunk writes */
379 static void /* PRIVATE */
380 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
384 /* Handle the no-compression case */
387 png_write_chunk_data(png_ptr, (png_bytep)comp->input,
388 (png_size_t)comp->input_len);
392 /* Write saved output buffers, if any */
393 for (i = 0; i < comp->num_output_ptr; i++)
395 png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i],
396 (png_size_t)png_ptr->zbuf_size);
397 png_free(png_ptr, comp->output_ptr[i]);
399 if (comp->max_output_ptr != 0)
400 png_free(png_ptr, comp->output_ptr);
401 /* Write anything left in zbuf */
402 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
403 png_write_chunk_data(png_ptr, png_ptr->zbuf,
404 (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
406 /* Reset zlib for another zTXt/iTXt or image data */
407 deflateReset(&png_ptr->zstream);
408 png_ptr->zstream.data_type = Z_BINARY;
412 /* Write the IHDR chunk, and update the png_struct with the necessary
413 * information. Note that the rest of this code depends upon this
414 * information being correct.
417 png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
418 int bit_depth, int color_type, int compression_type, int filter_type,
424 png_byte buf[13]; /* Buffer to store the IHDR info */
426 png_debug(1, "in png_write_IHDR");
428 /* Check that we have valid input data from the application info */
431 case PNG_COLOR_TYPE_GRAY:
438 case 16: png_ptr->channels = 1; break;
439 default: png_error(png_ptr,
440 "Invalid bit depth for grayscale image");
443 case PNG_COLOR_TYPE_RGB:
444 if (bit_depth != 8 && bit_depth != 16)
445 png_error(png_ptr, "Invalid bit depth for RGB image");
446 png_ptr->channels = 3;
448 case PNG_COLOR_TYPE_PALETTE:
454 case 8: png_ptr->channels = 1; break;
455 default: png_error(png_ptr, "Invalid bit depth for paletted image");
458 case PNG_COLOR_TYPE_GRAY_ALPHA:
459 if (bit_depth != 8 && bit_depth != 16)
460 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
461 png_ptr->channels = 2;
463 case PNG_COLOR_TYPE_RGB_ALPHA:
464 if (bit_depth != 8 && bit_depth != 16)
465 png_error(png_ptr, "Invalid bit depth for RGBA image");
466 png_ptr->channels = 4;
469 png_error(png_ptr, "Invalid image color type specified");
472 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
474 png_warning(png_ptr, "Invalid compression type specified");
475 compression_type = PNG_COMPRESSION_TYPE_BASE;
478 /* Write filter_method 64 (intrapixel differencing) only if
479 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
480 * 2. Libpng did not write a PNG signature (this filter_method is only
481 * used in PNG datastreams that are embedded in MNG datastreams) and
482 * 3. The application called png_permit_mng_features with a mask that
483 * included PNG_FLAG_MNG_FILTER_64 and
484 * 4. The filter_method is 64 and
485 * 5. The color_type is RGB or RGBA
488 #ifdef PNG_MNG_FEATURES_SUPPORTED
489 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
490 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
491 (color_type == PNG_COLOR_TYPE_RGB ||
492 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
493 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
495 filter_type != PNG_FILTER_TYPE_BASE)
497 png_warning(png_ptr, "Invalid filter type specified");
498 filter_type = PNG_FILTER_TYPE_BASE;
501 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
502 if (interlace_type != PNG_INTERLACE_NONE &&
503 interlace_type != PNG_INTERLACE_ADAM7)
505 png_warning(png_ptr, "Invalid interlace type specified");
506 interlace_type = PNG_INTERLACE_ADAM7;
509 interlace_type=PNG_INTERLACE_NONE;
512 /* Save the relevent information */
513 png_ptr->bit_depth = (png_byte)bit_depth;
514 png_ptr->color_type = (png_byte)color_type;
515 png_ptr->interlaced = (png_byte)interlace_type;
516 #ifdef PNG_MNG_FEATURES_SUPPORTED
517 png_ptr->filter_type = (png_byte)filter_type;
519 png_ptr->compression_type = (png_byte)compression_type;
520 png_ptr->width = width;
521 png_ptr->height = height;
523 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
524 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
525 /* Set the usr info, so any transformations can modify it */
526 png_ptr->usr_width = png_ptr->width;
527 png_ptr->usr_bit_depth = png_ptr->bit_depth;
528 png_ptr->usr_channels = png_ptr->channels;
530 /* Pack the header information into the buffer */
531 png_save_uint_32(buf, width);
532 png_save_uint_32(buf + 4, height);
533 buf[8] = (png_byte)bit_depth;
534 buf[9] = (png_byte)color_type;
535 buf[10] = (png_byte)compression_type;
536 buf[11] = (png_byte)filter_type;
537 buf[12] = (png_byte)interlace_type;
539 /* Write the chunk */
540 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
542 /* Initialize zlib with PNG info */
543 png_ptr->zstream.zalloc = png_zalloc;
544 png_ptr->zstream.zfree = png_zfree;
545 png_ptr->zstream.opaque = (voidpf)png_ptr;
546 if (!(png_ptr->do_filter))
548 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
549 png_ptr->bit_depth < 8)
550 png_ptr->do_filter = PNG_FILTER_NONE;
552 png_ptr->do_filter = PNG_ALL_FILTERS;
554 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
556 if (png_ptr->do_filter != PNG_FILTER_NONE)
557 png_ptr->zlib_strategy = Z_FILTERED;
559 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
561 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
562 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
563 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
564 png_ptr->zlib_mem_level = 8;
565 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
566 png_ptr->zlib_window_bits = 15;
567 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
568 png_ptr->zlib_method = 8;
569 ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
570 png_ptr->zlib_method, png_ptr->zlib_window_bits,
571 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
574 if (ret == Z_VERSION_ERROR) png_error(png_ptr,
575 "zlib failed to initialize compressor -- version error");
576 if (ret == Z_STREAM_ERROR) png_error(png_ptr,
577 "zlib failed to initialize compressor -- stream error");
578 if (ret == Z_MEM_ERROR) png_error(png_ptr,
579 "zlib failed to initialize compressor -- mem error");
580 png_error(png_ptr, "zlib failed to initialize compressor");
582 png_ptr->zstream.next_out = png_ptr->zbuf;
583 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
584 /* libpng is not interested in zstream.data_type */
585 /* Set it to a predefined value, to avoid its evaluation inside zlib */
586 png_ptr->zstream.data_type = Z_BINARY;
588 png_ptr->mode = PNG_HAVE_IHDR;
591 /* Write the palette. We are careful not to trust png_color to be in the
592 * correct order for PNG, so people can redefine it to any convenient
596 png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
603 png_debug(1, "in png_write_PLTE");
606 #ifdef PNG_MNG_FEATURES_SUPPORTED
607 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
609 num_pal == 0) || num_pal > 256)
611 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
613 png_error(png_ptr, "Invalid number of colors in palette");
617 png_warning(png_ptr, "Invalid number of colors in palette");
622 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
625 "Ignoring request to write a PLTE chunk in grayscale PNG");
629 png_ptr->num_palette = (png_uint_16)num_pal;
630 png_debug1(3, "num_palette = %d", png_ptr->num_palette);
632 png_write_chunk_start(png_ptr, (png_bytep)png_PLTE,
633 (png_uint_32)(num_pal * 3));
634 #ifdef PNG_POINTER_INDEXING_SUPPORTED
635 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
637 buf[0] = pal_ptr->red;
638 buf[1] = pal_ptr->green;
639 buf[2] = pal_ptr->blue;
640 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
643 /* This is a little slower but some buggy compilers need to do this
647 for (i = 0; i < num_pal; i++)
649 buf[0] = pal_ptr[i].red;
650 buf[1] = pal_ptr[i].green;
651 buf[2] = pal_ptr[i].blue;
652 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
655 png_write_chunk_end(png_ptr);
656 png_ptr->mode |= PNG_HAVE_PLTE;
659 /* Write an IDAT chunk */
661 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
665 png_debug(1, "in png_write_IDAT");
667 /* Optimize the CMF field in the zlib stream. */
668 /* This hack of the zlib stream is compliant to the stream specification. */
669 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
670 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
672 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
673 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
675 /* Avoid memory underflows and multiplication overflows.
677 * The conditions below are practically always satisfied;
678 * however, they still must be checked.
681 png_ptr->height < 16384 && png_ptr->width < 16384)
683 png_uint_32 uncompressed_idat_size = png_ptr->height *
685 png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
686 unsigned int z_cinfo = z_cmf >> 4;
687 unsigned int half_z_window_size = 1 << (z_cinfo + 7);
688 while (uncompressed_idat_size <= half_z_window_size &&
689 half_z_window_size >= 256)
692 half_z_window_size >>= 1;
694 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
695 if (data[0] != (png_byte)z_cmf)
697 data[0] = (png_byte)z_cmf;
699 data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);
705 "Invalid zlib compression method or flags in IDAT");
708 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
709 png_ptr->mode |= PNG_HAVE_IDAT;
712 /* Write an IEND chunk */
714 png_write_IEND(png_structp png_ptr)
718 png_debug(1, "in png_write_IEND");
720 png_write_chunk(png_ptr, (png_bytep)png_IEND, NULL,
722 png_ptr->mode |= PNG_HAVE_IEND;
725 #ifdef PNG_WRITE_gAMA_SUPPORTED
726 /* Write a gAMA chunk */
727 #ifdef PNG_FLOATING_POINT_SUPPORTED
729 png_write_gAMA(png_structp png_ptr, double file_gamma)
735 png_debug(1, "in png_write_gAMA");
737 /* file_gamma is saved in 1/100,000ths */
738 igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
739 png_save_uint_32(buf, igamma);
740 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
743 #ifdef PNG_FIXED_POINT_SUPPORTED
745 png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
750 png_debug(1, "in png_write_gAMA");
752 /* file_gamma is saved in 1/100,000ths */
753 png_save_uint_32(buf, (png_uint_32)file_gamma);
754 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
759 #ifdef PNG_WRITE_sRGB_SUPPORTED
760 /* Write a sRGB chunk */
762 png_write_sRGB(png_structp png_ptr, int srgb_intent)
767 png_debug(1, "in png_write_sRGB");
769 if (srgb_intent >= PNG_sRGB_INTENT_LAST)
771 "Invalid sRGB rendering intent specified");
772 buf[0]=(png_byte)srgb_intent;
773 png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
777 #ifdef PNG_WRITE_iCCP_SUPPORTED
778 /* Write an iCCP chunk */
780 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
781 png_charp profile, int profile_len)
786 compression_state comp;
787 int embedded_profile_len = 0;
789 png_debug(1, "in png_write_iCCP");
791 comp.num_output_ptr = 0;
792 comp.max_output_ptr = 0;
793 comp.output_ptr = NULL;
797 if ((name_len = png_check_keyword(png_ptr, name,
801 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
802 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
808 embedded_profile_len =
809 ((*( (png_bytep)profile ))<<24) |
810 ((*( (png_bytep)profile + 1))<<16) |
811 ((*( (png_bytep)profile + 2))<< 8) |
812 ((*( (png_bytep)profile + 3)) );
814 if (embedded_profile_len < 0)
817 "Embedded profile length in iCCP chunk is negative");
818 png_free(png_ptr, new_name);
822 if (profile_len < embedded_profile_len)
825 "Embedded profile length too large in iCCP chunk");
826 png_free(png_ptr, new_name);
830 if (profile_len > embedded_profile_len)
833 "Truncating profile to actual length in iCCP chunk");
834 profile_len = embedded_profile_len;
838 profile_len = png_text_compress(png_ptr, profile,
839 (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
841 /* Make sure we include the NULL after the name and the compression type */
842 png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
843 (png_uint_32)(name_len + profile_len + 2));
844 new_name[name_len + 1] = 0x00;
845 png_write_chunk_data(png_ptr, (png_bytep)new_name,
846 (png_size_t)(name_len + 2));
849 png_write_compressed_data_out(png_ptr, &comp);
851 png_write_chunk_end(png_ptr);
852 png_free(png_ptr, new_name);
856 #ifdef PNG_WRITE_sPLT_SUPPORTED
857 /* Write a sPLT chunk */
859 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
864 png_byte entrybuf[10];
865 png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
866 png_size_t palette_size = entry_size * spalette->nentries;
868 #ifndef PNG_POINTER_INDEXING_SUPPORTED
872 png_debug(1, "in png_write_sPLT");
874 if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
877 /* Make sure we include the NULL after the name */
878 png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
879 (png_uint_32)(name_len + 2 + palette_size));
880 png_write_chunk_data(png_ptr, (png_bytep)new_name,
881 (png_size_t)(name_len + 1));
882 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);
884 /* Loop through each palette entry, writing appropriately */
885 #ifdef PNG_POINTER_INDEXING_SUPPORTED
886 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
888 if (spalette->depth == 8)
890 entrybuf[0] = (png_byte)ep->red;
891 entrybuf[1] = (png_byte)ep->green;
892 entrybuf[2] = (png_byte)ep->blue;
893 entrybuf[3] = (png_byte)ep->alpha;
894 png_save_uint_16(entrybuf + 4, ep->frequency);
898 png_save_uint_16(entrybuf + 0, ep->red);
899 png_save_uint_16(entrybuf + 2, ep->green);
900 png_save_uint_16(entrybuf + 4, ep->blue);
901 png_save_uint_16(entrybuf + 6, ep->alpha);
902 png_save_uint_16(entrybuf + 8, ep->frequency);
904 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
907 ep=spalette->entries;
908 for (i=0; i>spalette->nentries; i++)
910 if (spalette->depth == 8)
912 entrybuf[0] = (png_byte)ep[i].red;
913 entrybuf[1] = (png_byte)ep[i].green;
914 entrybuf[2] = (png_byte)ep[i].blue;
915 entrybuf[3] = (png_byte)ep[i].alpha;
916 png_save_uint_16(entrybuf + 4, ep[i].frequency);
920 png_save_uint_16(entrybuf + 0, ep[i].red);
921 png_save_uint_16(entrybuf + 2, ep[i].green);
922 png_save_uint_16(entrybuf + 4, ep[i].blue);
923 png_save_uint_16(entrybuf + 6, ep[i].alpha);
924 png_save_uint_16(entrybuf + 8, ep[i].frequency);
926 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
930 png_write_chunk_end(png_ptr);
931 png_free(png_ptr, new_name);
935 #ifdef PNG_WRITE_sBIT_SUPPORTED
936 /* Write the sBIT chunk */
938 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
944 png_debug(1, "in png_write_sBIT");
946 /* Make sure we don't depend upon the order of PNG_COLOR_8 */
947 if (color_type & PNG_COLOR_MASK_COLOR)
951 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
952 png_ptr->usr_bit_depth);
953 if (sbit->red == 0 || sbit->red > maxbits ||
954 sbit->green == 0 || sbit->green > maxbits ||
955 sbit->blue == 0 || sbit->blue > maxbits)
957 png_warning(png_ptr, "Invalid sBIT depth specified");
961 buf[1] = sbit->green;
967 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
969 png_warning(png_ptr, "Invalid sBIT depth specified");
976 if (color_type & PNG_COLOR_MASK_ALPHA)
978 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
980 png_warning(png_ptr, "Invalid sBIT depth specified");
983 buf[size++] = sbit->alpha;
986 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
990 #ifdef PNG_WRITE_cHRM_SUPPORTED
991 /* Write the cHRM chunk */
992 #ifdef PNG_FLOATING_POINT_SUPPORTED
994 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
995 double red_x, double red_y, double green_x, double green_y,
996 double blue_x, double blue_y)
1001 png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y,
1002 int_green_x, int_green_y, int_blue_x, int_blue_y;
1004 png_debug(1, "in png_write_cHRM");
1006 int_white_x = (png_uint_32)(white_x * 100000.0 + 0.5);
1007 int_white_y = (png_uint_32)(white_y * 100000.0 + 0.5);
1008 int_red_x = (png_uint_32)(red_x * 100000.0 + 0.5);
1009 int_red_y = (png_uint_32)(red_y * 100000.0 + 0.5);
1010 int_green_x = (png_uint_32)(green_x * 100000.0 + 0.5);
1011 int_green_y = (png_uint_32)(green_y * 100000.0 + 0.5);
1012 int_blue_x = (png_uint_32)(blue_x * 100000.0 + 0.5);
1013 int_blue_y = (png_uint_32)(blue_y * 100000.0 + 0.5);
1015 #ifdef PNG_CHECK_cHRM_SUPPORTED
1016 if (png_check_cHRM_fixed(png_ptr, int_white_x, int_white_y,
1017 int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y))
1020 /* Each value is saved in 1/100,000ths */
1022 png_save_uint_32(buf, int_white_x);
1023 png_save_uint_32(buf + 4, int_white_y);
1025 png_save_uint_32(buf + 8, int_red_x);
1026 png_save_uint_32(buf + 12, int_red_y);
1028 png_save_uint_32(buf + 16, int_green_x);
1029 png_save_uint_32(buf + 20, int_green_y);
1031 png_save_uint_32(buf + 24, int_blue_x);
1032 png_save_uint_32(buf + 28, int_blue_y);
1034 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1038 #ifdef PNG_FIXED_POINT_SUPPORTED
1040 png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
1041 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
1042 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
1043 png_fixed_point blue_y)
1048 png_debug(1, "in png_write_cHRM");
1050 /* Each value is saved in 1/100,000ths */
1051 #ifdef PNG_CHECK_cHRM_SUPPORTED
1052 if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
1053 green_x, green_y, blue_x, blue_y))
1056 png_save_uint_32(buf, (png_uint_32)white_x);
1057 png_save_uint_32(buf + 4, (png_uint_32)white_y);
1059 png_save_uint_32(buf + 8, (png_uint_32)red_x);
1060 png_save_uint_32(buf + 12, (png_uint_32)red_y);
1062 png_save_uint_32(buf + 16, (png_uint_32)green_x);
1063 png_save_uint_32(buf + 20, (png_uint_32)green_y);
1065 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
1066 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
1068 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1074 #ifdef PNG_WRITE_tRNS_SUPPORTED
1075 /* Write the tRNS chunk */
1077 png_write_tRNS(png_structp png_ptr, png_bytep trans_alpha, png_color_16p tran,
1078 int num_trans, int color_type)
1083 png_debug(1, "in png_write_tRNS");
1085 if (color_type == PNG_COLOR_TYPE_PALETTE)
1087 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1089 png_warning(png_ptr, "Invalid number of transparent colors specified");
1092 /* Write the chunk out as it is */
1093 png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans_alpha,
1094 (png_size_t)num_trans);
1096 else if (color_type == PNG_COLOR_TYPE_GRAY)
1098 /* One 16 bit value */
1099 if (tran->gray >= (1 << png_ptr->bit_depth))
1101 png_warning(png_ptr,
1102 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1105 png_save_uint_16(buf, tran->gray);
1106 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
1108 else if (color_type == PNG_COLOR_TYPE_RGB)
1110 /* Three 16 bit values */
1111 png_save_uint_16(buf, tran->red);
1112 png_save_uint_16(buf + 2, tran->green);
1113 png_save_uint_16(buf + 4, tran->blue);
1114 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1116 png_warning(png_ptr,
1117 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1120 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
1124 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1129 #ifdef PNG_WRITE_bKGD_SUPPORTED
1130 /* Write the background chunk */
1132 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1137 png_debug(1, "in png_write_bKGD");
1139 if (color_type == PNG_COLOR_TYPE_PALETTE)
1142 #ifdef PNG_MNG_FEATURES_SUPPORTED
1143 (png_ptr->num_palette ||
1144 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
1146 back->index >= png_ptr->num_palette)
1148 png_warning(png_ptr, "Invalid background palette index");
1151 buf[0] = back->index;
1152 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
1154 else if (color_type & PNG_COLOR_MASK_COLOR)
1156 png_save_uint_16(buf, back->red);
1157 png_save_uint_16(buf + 2, back->green);
1158 png_save_uint_16(buf + 4, back->blue);
1159 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1161 png_warning(png_ptr,
1162 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1165 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
1169 if (back->gray >= (1 << png_ptr->bit_depth))
1171 png_warning(png_ptr,
1172 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1175 png_save_uint_16(buf, back->gray);
1176 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
1181 #ifdef PNG_WRITE_hIST_SUPPORTED
1182 /* Write the histogram */
1184 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
1190 png_debug(1, "in png_write_hIST");
1192 if (num_hist > (int)png_ptr->num_palette)
1194 png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
1195 png_ptr->num_palette);
1196 png_warning(png_ptr, "Invalid number of histogram entries specified");
1200 png_write_chunk_start(png_ptr, (png_bytep)png_hIST,
1201 (png_uint_32)(num_hist * 2));
1202 for (i = 0; i < num_hist; i++)
1204 png_save_uint_16(buf, hist[i]);
1205 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1207 png_write_chunk_end(png_ptr);
1211 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1212 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1213 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1214 * and if invalid, correct the keyword rather than discarding the entire
1215 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1216 * length, forbids leading or trailing whitespace, multiple internal spaces,
1217 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1219 * The new_key is allocated to hold the corrected keyword and must be freed
1220 * by the calling routine. This avoids problems with trying to write to
1221 * static keywords without having to have duplicate copies of the strings.
1223 png_size_t /* PRIVATE */
1224 png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1231 png_debug(1, "in png_check_keyword");
1235 if (key == NULL || (key_len = png_strlen(key)) == 0)
1237 png_warning(png_ptr, "zero length keyword");
1238 return ((png_size_t)0);
1241 png_debug1(2, "Keyword to be checked is '%s'", key);
1243 *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
1244 if (*new_key == NULL)
1246 png_warning(png_ptr, "Out of memory while procesing keyword");
1247 return ((png_size_t)0);
1250 /* Replace non-printing characters with a blank and print a warning */
1251 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1253 if ((png_byte)*kp < 0x20 ||
1254 ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
1256 #ifdef PNG_STDIO_SUPPORTED
1259 png_snprintf(msg, 40,
1260 "invalid keyword character 0x%02X", (png_byte)*kp);
1261 png_warning(png_ptr, msg);
1263 png_warning(png_ptr, "invalid character in keyword");
1274 /* Remove any trailing white space. */
1275 kp = *new_key + key_len - 1;
1278 png_warning(png_ptr, "trailing spaces removed from keyword");
1287 /* Remove any leading white space. */
1291 png_warning(png_ptr, "leading spaces removed from keyword");
1300 png_debug1(2, "Checking for multiple internal spaces in '%s'", kp);
1302 /* Remove multiple internal spaces. */
1303 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1305 if (*kp == ' ' && kflag == 0)
1310 else if (*kp == ' ')
1323 png_warning(png_ptr, "extra interior spaces removed from keyword");
1327 png_free(png_ptr, *new_key);
1328 png_warning(png_ptr, "Zero length keyword");
1333 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1334 (*new_key)[79] = '\0';
1342 #ifdef PNG_WRITE_tEXt_SUPPORTED
1343 /* Write a tEXt chunk */
1345 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1346 png_size_t text_len)
1352 png_debug(1, "in png_write_tEXt");
1354 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1357 if (text == NULL || *text == '\0')
1360 text_len = png_strlen(text);
1362 /* Make sure we include the 0 after the key */
1363 png_write_chunk_start(png_ptr, (png_bytep)png_tEXt,
1364 (png_uint_32)(key_len + text_len + 1));
1366 * We leave it to the application to meet PNG-1.0 requirements on the
1367 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1368 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1369 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1371 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1372 (png_size_t)(key_len + 1));
1374 png_write_chunk_data(png_ptr, (png_bytep)text, (png_size_t)text_len);
1376 png_write_chunk_end(png_ptr);
1377 png_free(png_ptr, new_key);
1381 #ifdef PNG_WRITE_zTXt_SUPPORTED
1382 /* Write a compressed text chunk */
1384 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
1385 png_size_t text_len, int compression)
1391 compression_state comp;
1393 png_debug(1, "in png_write_zTXt");
1395 comp.num_output_ptr = 0;
1396 comp.max_output_ptr = 0;
1397 comp.output_ptr = NULL;
1401 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1403 png_free(png_ptr, new_key);
1407 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1409 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1410 png_free(png_ptr, new_key);
1414 text_len = png_strlen(text);
1416 /* Compute the compressed data; do it now for the length */
1417 text_len = png_text_compress(png_ptr, text, text_len, compression,
1420 /* Write start of chunk */
1421 png_write_chunk_start(png_ptr, (png_bytep)png_zTXt,
1422 (png_uint_32)(key_len+text_len + 2));
1424 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1425 (png_size_t)(key_len + 1));
1426 png_free(png_ptr, new_key);
1428 buf[0] = (png_byte)compression;
1429 /* Write compression */
1430 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1431 /* Write the compressed data */
1432 png_write_compressed_data_out(png_ptr, &comp);
1434 /* Close the chunk */
1435 png_write_chunk_end(png_ptr);
1439 #ifdef PNG_WRITE_iTXt_SUPPORTED
1440 /* Write an iTXt chunk */
1442 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1443 png_charp lang, png_charp lang_key, png_charp text)
1446 png_size_t lang_len, key_len, lang_key_len, text_len;
1448 png_charp new_key = NULL;
1450 compression_state comp;
1452 png_debug(1, "in png_write_iTXt");
1454 comp.num_output_ptr = 0;
1455 comp.max_output_ptr = 0;
1456 comp.output_ptr = NULL;
1459 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1462 if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1464 png_warning(png_ptr, "Empty language field in iTXt chunk");
1469 if (lang_key == NULL)
1472 lang_key_len = png_strlen(lang_key);
1477 text_len = png_strlen(text);
1479 /* Compute the compressed data; do it now for the length */
1480 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1484 /* Make sure we include the compression flag, the compression byte,
1485 * and the NULs after the key, lang, and lang_key parts */
1487 png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
1489 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1495 /* We leave it to the application to meet PNG-1.0 requirements on the
1496 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1497 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1498 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1500 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1501 (png_size_t)(key_len + 1));
1503 /* Set the compression flag */
1504 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1505 compression == PNG_TEXT_COMPRESSION_NONE)
1507 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1509 /* Set the compression method */
1511 png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
1514 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf),
1515 (png_size_t)(lang_len + 1));
1516 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf),
1517 (png_size_t)(lang_key_len + 1));
1518 png_write_compressed_data_out(png_ptr, &comp);
1520 png_write_chunk_end(png_ptr);
1521 png_free(png_ptr, new_key);
1522 png_free(png_ptr, new_lang);
1526 #ifdef PNG_WRITE_oFFs_SUPPORTED
1527 /* Write the oFFs chunk */
1529 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1535 png_debug(1, "in png_write_oFFs");
1537 if (unit_type >= PNG_OFFSET_LAST)
1538 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1540 png_save_int_32(buf, x_offset);
1541 png_save_int_32(buf + 4, y_offset);
1542 buf[8] = (png_byte)unit_type;
1544 png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
1547 #ifdef PNG_WRITE_pCAL_SUPPORTED
1548 /* Write the pCAL chunk (described in the PNG extensions document) */
1550 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1551 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1554 png_size_t purpose_len, units_len, total_len;
1555 png_uint_32p params_len;
1557 png_charp new_purpose;
1560 png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
1562 if (type >= PNG_EQUATION_LAST)
1563 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1565 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1566 png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
1567 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1568 png_debug1(3, "pCAL units length = %d", (int)units_len);
1569 total_len = purpose_len + units_len + 10;
1571 params_len = (png_uint_32p)png_malloc(png_ptr,
1572 (png_alloc_size_t)(nparams * png_sizeof(png_uint_32)));
1574 /* Find the length of each parameter, making sure we don't count the
1575 null terminator for the last parameter. */
1576 for (i = 0; i < nparams; i++)
1578 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1579 png_debug2(3, "pCAL parameter %d length = %lu", i,
1580 (unsigned long) params_len[i]);
1581 total_len += (png_size_t)params_len[i];
1584 png_debug1(3, "pCAL total length = %d", (int)total_len);
1585 png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
1586 png_write_chunk_data(png_ptr, (png_bytep)new_purpose,
1587 (png_size_t)purpose_len);
1588 png_save_int_32(buf, X0);
1589 png_save_int_32(buf + 4, X1);
1590 buf[8] = (png_byte)type;
1591 buf[9] = (png_byte)nparams;
1592 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1593 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1595 png_free(png_ptr, new_purpose);
1597 for (i = 0; i < nparams; i++)
1599 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1600 (png_size_t)params_len[i]);
1603 png_free(png_ptr, params_len);
1604 png_write_chunk_end(png_ptr);
1608 #ifdef PNG_WRITE_sCAL_SUPPORTED
1609 /* Write the sCAL chunk */
1610 #if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
1612 png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
1616 png_size_t total_len;
1618 png_debug(1, "in png_write_sCAL");
1620 buf[0] = (char)unit;
1621 png_snprintf(buf + 1, 63, "%12.12e", width);
1622 total_len = 1 + png_strlen(buf + 1) + 1;
1623 png_snprintf(buf + total_len, 64-total_len, "%12.12e", height);
1624 total_len += png_strlen(buf + total_len);
1626 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1627 png_write_chunk(png_ptr, (png_bytep)png_sCAL, (png_bytep)buf, total_len);
1630 #ifdef PNG_FIXED_POINT_SUPPORTED
1632 png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
1637 png_size_t wlen, hlen, total_len;
1639 png_debug(1, "in png_write_sCAL_s");
1641 wlen = png_strlen(width);
1642 hlen = png_strlen(height);
1643 total_len = wlen + hlen + 2;
1646 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
1650 buf[0] = (png_byte)unit;
1651 png_memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
1652 png_memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
1654 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1655 png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len);
1661 #ifdef PNG_WRITE_pHYs_SUPPORTED
1662 /* Write the pHYs chunk */
1664 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
1665 png_uint_32 y_pixels_per_unit,
1671 png_debug(1, "in png_write_pHYs");
1673 if (unit_type >= PNG_RESOLUTION_LAST)
1674 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1676 png_save_uint_32(buf, x_pixels_per_unit);
1677 png_save_uint_32(buf + 4, y_pixels_per_unit);
1678 buf[8] = (png_byte)unit_type;
1680 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
1684 #ifdef PNG_WRITE_tIME_SUPPORTED
1685 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1686 * or png_convert_from_time_t(), or fill in the structure yourself.
1689 png_write_tIME(png_structp png_ptr, png_timep mod_time)
1694 png_debug(1, "in png_write_tIME");
1696 if (mod_time->month > 12 || mod_time->month < 1 ||
1697 mod_time->day > 31 || mod_time->day < 1 ||
1698 mod_time->hour > 23 || mod_time->second > 60)
1700 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1704 png_save_uint_16(buf, mod_time->year);
1705 buf[2] = mod_time->month;
1706 buf[3] = mod_time->day;
1707 buf[4] = mod_time->hour;
1708 buf[5] = mod_time->minute;
1709 buf[6] = mod_time->second;
1711 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
1715 /* Initializes the row writing capability of libpng */
1717 png_write_start_row(png_structp png_ptr)
1719 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
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};
1735 png_size_t buf_size;
1737 png_debug(1, "in png_write_start_row");
1739 buf_size = (png_size_t)(PNG_ROWBYTES(
1740 png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
1742 /* Set up row buffer */
1743 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,
1744 (png_alloc_size_t)buf_size);
1745 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1747 #ifdef PNG_WRITE_FILTER_SUPPORTED
1748 /* Set up filtering buffer, if using this filter */
1749 if (png_ptr->do_filter & PNG_FILTER_SUB)
1751 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1752 (png_alloc_size_t)(png_ptr->rowbytes + 1));
1753 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1756 /* We only need to keep the previous row if we are using one of these. */
1757 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1759 /* Set up previous row buffer */
1760 png_ptr->prev_row = (png_bytep)png_calloc(png_ptr,
1761 (png_alloc_size_t)buf_size);
1763 if (png_ptr->do_filter & PNG_FILTER_UP)
1765 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1766 (png_size_t)(png_ptr->rowbytes + 1));
1767 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1770 if (png_ptr->do_filter & PNG_FILTER_AVG)
1772 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1773 (png_alloc_size_t)(png_ptr->rowbytes + 1));
1774 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1777 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1779 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1780 (png_size_t)(png_ptr->rowbytes + 1));
1781 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1784 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1786 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1787 /* If interlaced, we need to set up width and height of pass */
1788 if (png_ptr->interlaced)
1790 if (!(png_ptr->transformations & PNG_INTERLACE))
1792 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1793 png_pass_ystart[0]) / png_pass_yinc[0];
1794 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1795 png_pass_start[0]) / png_pass_inc[0];
1799 png_ptr->num_rows = png_ptr->height;
1800 png_ptr->usr_width = png_ptr->width;
1806 png_ptr->num_rows = png_ptr->height;
1807 png_ptr->usr_width = png_ptr->width;
1809 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1810 png_ptr->zstream.next_out = png_ptr->zbuf;
1813 /* Internal use only. Called when finished processing a row of data. */
1815 png_write_finish_row(png_structp png_ptr)
1817 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1818 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1820 /* Start of interlace block */
1821 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1823 /* Offset to next interlace block */
1824 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1826 /* Start of interlace block in the y direction */
1827 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1829 /* Offset to next interlace block in the y direction */
1830 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1835 png_debug(1, "in png_write_finish_row");
1838 png_ptr->row_number++;
1840 /* See if we are done */
1841 if (png_ptr->row_number < png_ptr->num_rows)
1844 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1845 /* If interlaced, go to next pass */
1846 if (png_ptr->interlaced)
1848 png_ptr->row_number = 0;
1849 if (png_ptr->transformations & PNG_INTERLACE)
1855 /* Loop until we find a non-zero width or height pass */
1859 if (png_ptr->pass >= 7)
1861 png_ptr->usr_width = (png_ptr->width +
1862 png_pass_inc[png_ptr->pass] - 1 -
1863 png_pass_start[png_ptr->pass]) /
1864 png_pass_inc[png_ptr->pass];
1865 png_ptr->num_rows = (png_ptr->height +
1866 png_pass_yinc[png_ptr->pass] - 1 -
1867 png_pass_ystart[png_ptr->pass]) /
1868 png_pass_yinc[png_ptr->pass];
1869 if (png_ptr->transformations & PNG_INTERLACE)
1871 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1875 /* Reset the row above the image for the next pass */
1876 if (png_ptr->pass < 7)
1878 if (png_ptr->prev_row != NULL)
1879 png_memset(png_ptr->prev_row, 0,
1880 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
1881 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
1887 /* If we get here, we've just written the last row, so we need
1888 to flush the compressor */
1891 /* Tell the compressor we are done */
1892 ret = deflate(&png_ptr->zstream, Z_FINISH);
1893 /* Check for an error */
1896 /* Check to see if we need more room */
1897 if (!(png_ptr->zstream.avail_out))
1899 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1900 png_ptr->zstream.next_out = png_ptr->zbuf;
1901 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1904 else if (ret != Z_STREAM_END)
1906 if (png_ptr->zstream.msg != NULL)
1907 png_error(png_ptr, png_ptr->zstream.msg);
1909 png_error(png_ptr, "zlib error");
1911 } while (ret != Z_STREAM_END);
1913 /* Write any extra space */
1914 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1916 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1917 png_ptr->zstream.avail_out);
1920 deflateReset(&png_ptr->zstream);
1921 png_ptr->zstream.data_type = Z_BINARY;
1924 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1925 /* Pick out the correct pixels for the interlace pass.
1926 * The basic idea here is to go through the row with a source
1927 * pointer and a destination pointer (sp and dp), and copy the
1928 * correct pixels for the pass. As the row gets compacted,
1929 * sp will always be >= dp, so we should never overwrite anything.
1930 * See the default: case for the easiest code to understand.
1933 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1935 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1937 /* Start of interlace block */
1938 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1940 /* Offset to next interlace block */
1941 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1943 png_debug(1, "in png_do_write_interlace");
1945 /* We don't have to do anything on the last pass (6) */
1948 /* Each pixel depth is handled separately */
1949 switch (row_info->pixel_depth)
1959 png_uint_32 row_width = row_info->width;
1964 for (i = png_pass_start[pass]; i < row_width;
1965 i += png_pass_inc[pass])
1967 sp = row + (png_size_t)(i >> 3);
1968 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
1969 d |= (value << shift);
1974 *dp++ = (png_byte)d;
1993 png_uint_32 row_width = row_info->width;
1998 for (i = png_pass_start[pass]; i < row_width;
1999 i += png_pass_inc[pass])
2001 sp = row + (png_size_t)(i >> 2);
2002 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
2003 d |= (value << shift);
2008 *dp++ = (png_byte)d;
2026 png_uint_32 row_width = row_info->width;
2031 for (i = png_pass_start[pass]; i < row_width;
2032 i += png_pass_inc[pass])
2034 sp = row + (png_size_t)(i >> 1);
2035 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
2036 d |= (value << shift);
2041 *dp++ = (png_byte)d;
2056 png_uint_32 row_width = row_info->width;
2057 png_size_t pixel_bytes;
2059 /* Start at the beginning */
2061 /* Find out how many bytes each pixel takes up */
2062 pixel_bytes = (row_info->pixel_depth >> 3);
2063 /* Loop through the row, only looking at the pixels that
2065 for (i = png_pass_start[pass]; i < row_width;
2066 i += png_pass_inc[pass])
2068 /* Find out where the original pixel is */
2069 sp = row + (png_size_t)i * pixel_bytes;
2070 /* Move the pixel */
2072 png_memcpy(dp, sp, pixel_bytes);
2079 /* Set new row width */
2080 row_info->width = (row_info->width +
2081 png_pass_inc[pass] - 1 -
2082 png_pass_start[pass]) /
2084 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2090 /* This filters the row, chooses which filter to use, if it has not already
2091 * been specified by the application, and then writes the row out with the
2094 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
2095 #define PNG_HISHIFT 10
2096 #define PNG_LOMASK ((png_uint_32)0xffffL)
2097 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2099 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2102 #ifdef PNG_WRITE_FILTER_SUPPORTED
2103 png_bytep prev_row, row_buf;
2104 png_uint_32 mins, bpp;
2105 png_byte filter_to_do = png_ptr->do_filter;
2106 png_uint_32 row_bytes = row_info->rowbytes;
2107 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2108 int num_p_filters = (int)png_ptr->num_prev_filters;
2111 png_debug(1, "in png_write_find_filter");
2113 #ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2114 if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
2116 /* These will never be selected so we need not test them. */
2117 filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
2121 /* Find out how many bytes offset each pixel is */
2122 bpp = (row_info->pixel_depth + 7) >> 3;
2124 prev_row = png_ptr->prev_row;
2126 best_row = png_ptr->row_buf;
2127 #ifdef PNG_WRITE_FILTER_SUPPORTED
2131 /* The prediction method we use is to find which method provides the
2132 * smallest value when summing the absolute values of the distances
2133 * from zero, using anything >= 128 as negative numbers. This is known
2134 * as the "minimum sum of absolute differences" heuristic. Other
2135 * heuristics are the "weighted minimum sum of absolute differences"
2136 * (experimental and can in theory improve compression), and the "zlib
2137 * predictive" method (not implemented yet), which does test compressions
2138 * of lines using different filter methods, and then chooses the
2139 * (series of) filter(s) that give minimum compressed data size (VERY
2140 * computationally expensive).
2142 * GRR 980525: consider also
2143 * (1) minimum sum of absolute differences from running average (i.e.,
2144 * keep running sum of non-absolute differences & count of bytes)
2145 * [track dispersion, too? restart average if dispersion too large?]
2146 * (1b) minimum sum of absolute differences from sliding average, probably
2147 * with window size <= deflate window (usually 32K)
2148 * (2) minimum sum of squared differences from zero or running average
2149 * (i.e., ~ root-mean-square approach)
2153 /* We don't need to test the 'no filter' case if this is the only filter
2154 * that has been chosen, as it doesn't actually do anything to the data.
2156 if ((filter_to_do & PNG_FILTER_NONE) &&
2157 filter_to_do != PNG_FILTER_NONE)
2160 png_uint_32 sum = 0;
2164 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2167 sum += (v < 128) ? v : 256 - v;
2170 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2171 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2173 png_uint_32 sumhi, sumlo;
2175 sumlo = sum & PNG_LOMASK;
2176 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
2178 /* Reduce the sum if we match any of the previous rows */
2179 for (j = 0; j < num_p_filters; j++)
2181 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2183 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2185 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2190 /* Factor in the cost of this filter (this is here for completeness,
2191 * but it makes no sense to have a "cost" for the NONE filter, as
2192 * it has the minimum possible computational cost - none).
2194 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2196 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2199 if (sumhi > PNG_HIMASK)
2202 sum = (sumhi << PNG_HISHIFT) + sumlo;
2209 if (filter_to_do == PNG_FILTER_SUB)
2210 /* It's the only filter so no testing is needed */
2212 png_bytep rp, lp, dp;
2214 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2219 for (lp = row_buf + 1; i < row_bytes;
2220 i++, rp++, lp++, dp++)
2222 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2224 best_row = png_ptr->sub_row;
2227 else if (filter_to_do & PNG_FILTER_SUB)
2229 png_bytep rp, dp, lp;
2230 png_uint_32 sum = 0, lmins = mins;
2234 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2235 /* We temporarily increase the "minimum sum" by the factor we
2236 * would reduce the sum of this filter, so that we can do the
2237 * early exit comparison without scaling the sum each time.
2239 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2242 png_uint_32 lmhi, lmlo;
2243 lmlo = lmins & PNG_LOMASK;
2244 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2246 for (j = 0; j < num_p_filters; j++)
2248 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2250 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2252 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2257 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2259 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2262 if (lmhi > PNG_HIMASK)
2265 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2269 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2274 sum += (v < 128) ? v : 256 - v;
2276 for (lp = row_buf + 1; i < row_bytes;
2277 i++, rp++, lp++, dp++)
2279 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2281 sum += (v < 128) ? v : 256 - v;
2283 if (sum > lmins) /* We are already worse, don't continue. */
2287 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2288 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2291 png_uint_32 sumhi, sumlo;
2292 sumlo = sum & PNG_LOMASK;
2293 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2295 for (j = 0; j < num_p_filters; j++)
2297 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2299 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
2301 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
2306 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2308 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2311 if (sumhi > PNG_HIMASK)
2314 sum = (sumhi << PNG_HISHIFT) + sumlo;
2321 best_row = png_ptr->sub_row;
2326 if (filter_to_do == PNG_FILTER_UP)
2328 png_bytep rp, dp, pp;
2331 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2332 pp = prev_row + 1; i < row_bytes;
2333 i++, rp++, pp++, dp++)
2335 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2337 best_row = png_ptr->up_row;
2340 else if (filter_to_do & PNG_FILTER_UP)
2342 png_bytep rp, dp, pp;
2343 png_uint_32 sum = 0, lmins = mins;
2348 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2349 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2352 png_uint_32 lmhi, lmlo;
2353 lmlo = lmins & PNG_LOMASK;
2354 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2356 for (j = 0; j < num_p_filters; j++)
2358 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2360 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2362 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2367 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2369 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2372 if (lmhi > PNG_HIMASK)
2375 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2379 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2380 pp = prev_row + 1; i < row_bytes; i++)
2382 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2384 sum += (v < 128) ? v : 256 - v;
2386 if (sum > lmins) /* We are already worse, don't continue. */
2390 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2391 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2394 png_uint_32 sumhi, sumlo;
2395 sumlo = sum & PNG_LOMASK;
2396 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2398 for (j = 0; j < num_p_filters; j++)
2400 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2402 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2404 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2409 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2411 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2414 if (sumhi > PNG_HIMASK)
2417 sum = (sumhi << PNG_HISHIFT) + sumlo;
2424 best_row = png_ptr->up_row;
2429 if (filter_to_do == PNG_FILTER_AVG)
2431 png_bytep rp, dp, pp, lp;
2433 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2434 pp = prev_row + 1; i < bpp; i++)
2436 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2438 for (lp = row_buf + 1; i < row_bytes; i++)
2440 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2443 best_row = png_ptr->avg_row;
2446 else if (filter_to_do & PNG_FILTER_AVG)
2448 png_bytep rp, dp, pp, lp;
2449 png_uint_32 sum = 0, lmins = mins;
2453 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2454 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2457 png_uint_32 lmhi, lmlo;
2458 lmlo = lmins & PNG_LOMASK;
2459 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2461 for (j = 0; j < num_p_filters; j++)
2463 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
2465 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2467 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2472 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2474 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2477 if (lmhi > PNG_HIMASK)
2480 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2484 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2485 pp = prev_row + 1; i < bpp; i++)
2487 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2489 sum += (v < 128) ? v : 256 - v;
2491 for (lp = row_buf + 1; i < row_bytes; i++)
2494 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
2496 sum += (v < 128) ? v : 256 - v;
2498 if (sum > lmins) /* We are already worse, don't continue. */
2502 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2503 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2506 png_uint_32 sumhi, sumlo;
2507 sumlo = sum & PNG_LOMASK;
2508 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2510 for (j = 0; j < num_p_filters; j++)
2512 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2514 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2516 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2521 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2523 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2526 if (sumhi > PNG_HIMASK)
2529 sum = (sumhi << PNG_HISHIFT) + sumlo;
2536 best_row = png_ptr->avg_row;
2541 if (filter_to_do == PNG_FILTER_PAETH)
2543 png_bytep rp, dp, pp, cp, lp;
2545 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2546 pp = prev_row + 1; i < bpp; i++)
2548 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2551 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2553 int a, b, c, pa, pb, pc, p;
2567 pa = p < 0 ? -p : p;
2568 pb = pc < 0 ? -pc : pc;
2569 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2572 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2574 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2576 best_row = png_ptr->paeth_row;
2579 else if (filter_to_do & PNG_FILTER_PAETH)
2581 png_bytep rp, dp, pp, cp, lp;
2582 png_uint_32 sum = 0, lmins = mins;
2586 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2587 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2590 png_uint_32 lmhi, lmlo;
2591 lmlo = lmins & PNG_LOMASK;
2592 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2594 for (j = 0; j < num_p_filters; j++)
2596 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2598 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2600 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2605 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2607 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2610 if (lmhi > PNG_HIMASK)
2613 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2617 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2618 pp = prev_row + 1; i < bpp; i++)
2620 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2622 sum += (v < 128) ? v : 256 - v;
2625 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2627 int a, b, c, pa, pb, pc, p;
2633 #ifndef PNG_SLOW_PAETH
2641 pa = p < 0 ? -p : p;
2642 pb = pc < 0 ? -pc : pc;
2643 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2645 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2646 #else /* PNG_SLOW_PAETH */
2651 if (pa <= pb && pa <= pc)
2657 #endif /* PNG_SLOW_PAETH */
2659 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2661 sum += (v < 128) ? v : 256 - v;
2663 if (sum > lmins) /* We are already worse, don't continue. */
2667 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2668 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2671 png_uint_32 sumhi, sumlo;
2672 sumlo = sum & PNG_LOMASK;
2673 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2675 for (j = 0; j < num_p_filters; j++)
2677 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2679 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2681 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2686 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2688 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2691 if (sumhi > PNG_HIMASK)
2694 sum = (sumhi << PNG_HISHIFT) + sumlo;
2700 best_row = png_ptr->paeth_row;
2703 #endif /* PNG_WRITE_FILTER_SUPPORTED */
2704 /* Do the actual writing of the filtered row data from the chosen filter. */
2706 png_write_filtered_row(png_ptr, best_row);
2708 #ifdef PNG_WRITE_FILTER_SUPPORTED
2709 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
2710 /* Save the type of filter we picked this time for future calculations */
2711 if (png_ptr->num_prev_filters > 0)
2714 for (j = 1; j < num_p_filters; j++)
2716 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
2718 png_ptr->prev_filters[j] = best_row[0];
2721 #endif /* PNG_WRITE_FILTER_SUPPORTED */
2725 /* Do the actual writing of a previously filtered row. */
2727 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2729 png_debug(1, "in png_write_filtered_row");
2731 png_debug1(2, "filter = %d", filtered_row[0]);
2732 /* Set up the zlib input buffer */
2734 png_ptr->zstream.next_in = filtered_row;
2735 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2736 /* Repeat until we have compressed all the data */
2739 int ret; /* Return of zlib */
2741 /* Compress the data */
2742 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2743 /* Check for compression errors */
2746 if (png_ptr->zstream.msg != NULL)
2747 png_error(png_ptr, png_ptr->zstream.msg);
2749 png_error(png_ptr, "zlib error");
2752 /* See if it is time to write another IDAT */
2753 if (!(png_ptr->zstream.avail_out))
2755 /* Write the IDAT and reset the zlib output buffer */
2756 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2757 png_ptr->zstream.next_out = png_ptr->zbuf;
2758 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2760 /* Repeat until all data has been compressed */
2761 } while (png_ptr->zstream.avail_in);
2763 /* Swap the current and previous rows */
2764 if (png_ptr->prev_row != NULL)
2768 tptr = png_ptr->prev_row;
2769 png_ptr->prev_row = png_ptr->row_buf;
2770 png_ptr->row_buf = tptr;
2773 /* Finish row - updates counters and flushes zlib if last row */
2774 png_write_finish_row(png_ptr);
2776 #ifdef PNG_WRITE_FLUSH_SUPPORTED
2777 png_ptr->flush_rows++;
2779 if (png_ptr->flush_dist > 0 &&
2780 png_ptr->flush_rows >= png_ptr->flush_dist)
2782 png_write_flush(png_ptr);
2786 #endif /* PNG_WRITE_SUPPORTED */