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1 | |
2 | /* pngwutil.c - utilities to write a PNG file | |
3 | * | |
a626cc03 | 4 | * libpng 1.0.3 - January 14, 1999 |
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5 | * For conditions of distribution and use, see copyright notice in png.h |
6 | * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. | |
7 | * Copyright (c) 1996, 1997 Andreas Dilger | |
a626cc03 | 8 | * Copyright (c) 1998, 1999 Glenn Randers-Pehrson |
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9 | */ |
10 | ||
11 | #define PNG_INTERNAL | |
a626cc03 | 12 | #include "png.h" |
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13 | |
14 | /* Place a 32-bit number into a buffer in PNG byte order. We work | |
15 | * with unsigned numbers for convenience, although one supported | |
16 | * ancillary chunk uses signed (two's complement) numbers. | |
17 | */ | |
18 | void | |
19 | png_save_uint_32(png_bytep buf, png_uint_32 i) | |
20 | { | |
21 | buf[0] = (png_byte)((i >> 24) & 0xff); | |
22 | buf[1] = (png_byte)((i >> 16) & 0xff); | |
23 | buf[2] = (png_byte)((i >> 8) & 0xff); | |
24 | buf[3] = (png_byte)(i & 0xff); | |
25 | } | |
26 | ||
27 | #if defined(PNG_WRITE_pCAL_SUPPORTED) | |
28 | /* The png_save_int_32 function assumes integers are stored in two's | |
29 | * complement format. If this isn't the case, then this routine needs to | |
30 | * be modified to write data in two's complement format. | |
31 | */ | |
32 | void | |
33 | png_save_int_32(png_bytep buf, png_int_32 i) | |
34 | { | |
35 | buf[0] = (png_byte)((i >> 24) & 0xff); | |
36 | buf[1] = (png_byte)((i >> 16) & 0xff); | |
37 | buf[2] = (png_byte)((i >> 8) & 0xff); | |
38 | buf[3] = (png_byte)(i & 0xff); | |
39 | } | |
40 | #endif | |
41 | ||
42 | /* Place a 16-bit number into a buffer in PNG byte order. | |
43 | * The parameter is declared unsigned int, not png_uint_16, | |
44 | * just to avoid potential problems on pre-ANSI C compilers. | |
45 | */ | |
46 | void | |
47 | png_save_uint_16(png_bytep buf, unsigned int i) | |
48 | { | |
49 | buf[0] = (png_byte)((i >> 8) & 0xff); | |
50 | buf[1] = (png_byte)(i & 0xff); | |
51 | } | |
52 | ||
53 | /* Write a PNG chunk all at once. The type is an array of ASCII characters | |
54 | * representing the chunk name. The array must be at least 4 bytes in | |
55 | * length, and does not need to be null terminated. To be safe, pass the | |
56 | * pre-defined chunk names here, and if you need a new one, define it | |
57 | * where the others are defined. The length is the length of the data. | |
58 | * All the data must be present. If that is not possible, use the | |
59 | * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() | |
60 | * functions instead. | |
61 | */ | |
62 | void | |
63 | png_write_chunk(png_structp png_ptr, png_bytep chunk_name, | |
64 | png_bytep data, png_size_t length) | |
65 | { | |
66 | png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length); | |
67 | png_write_chunk_data(png_ptr, data, length); | |
68 | png_write_chunk_end(png_ptr); | |
69 | } | |
70 | ||
71 | /* Write the start of a PNG chunk. The type is the chunk type. | |
72 | * The total_length is the sum of the lengths of all the data you will be | |
73 | * passing in png_write_chunk_data(). | |
74 | */ | |
75 | void | |
76 | png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name, | |
77 | png_uint_32 length) | |
78 | { | |
79 | png_byte buf[4]; | |
80 | png_debug2(0, "Writing %s chunk (%d bytes)\n", chunk_name, length); | |
81 | ||
82 | /* write the length */ | |
83 | png_save_uint_32(buf, length); | |
84 | png_write_data(png_ptr, buf, (png_size_t)4); | |
85 | ||
86 | /* write the chunk name */ | |
87 | png_write_data(png_ptr, chunk_name, (png_size_t)4); | |
88 | /* reset the crc and run it over the chunk name */ | |
89 | png_reset_crc(png_ptr); | |
90 | png_calculate_crc(png_ptr, chunk_name, (png_size_t)4); | |
91 | } | |
92 | ||
93 | /* Write the data of a PNG chunk started with png_write_chunk_start(). | |
94 | * Note that multiple calls to this function are allowed, and that the | |
95 | * sum of the lengths from these calls *must* add up to the total_length | |
96 | * given to png_write_chunk_start(). | |
97 | */ | |
98 | void | |
99 | png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length) | |
100 | { | |
101 | /* write the data, and run the CRC over it */ | |
102 | if (data != NULL && length > 0) | |
103 | { | |
104 | png_calculate_crc(png_ptr, data, length); | |
105 | png_write_data(png_ptr, data, length); | |
106 | } | |
107 | } | |
108 | ||
109 | /* Finish a chunk started with png_write_chunk_start(). */ | |
110 | void | |
111 | png_write_chunk_end(png_structp png_ptr) | |
112 | { | |
113 | png_byte buf[4]; | |
114 | ||
115 | /* write the crc */ | |
116 | png_save_uint_32(buf, png_ptr->crc); | |
117 | ||
118 | png_write_data(png_ptr, buf, (png_size_t)4); | |
119 | } | |
120 | ||
121 | /* Simple function to write the signature. If we have already written | |
122 | * the magic bytes of the signature, or more likely, the PNG stream is | |
123 | * being embedded into another stream and doesn't need its own signature, | |
124 | * we should call png_set_sig_bytes() to tell libpng how many of the | |
125 | * bytes have already been written. | |
126 | */ | |
127 | void | |
128 | png_write_sig(png_structp png_ptr) | |
129 | { | |
130 | /* write the rest of the 8 byte signature */ | |
131 | png_write_data(png_ptr, &png_sig[png_ptr->sig_bytes], | |
132 | (png_size_t)8 - png_ptr->sig_bytes); | |
133 | } | |
134 | ||
135 | /* Write the IHDR chunk, and update the png_struct with the necessary | |
136 | * information. Note that the rest of this code depends upon this | |
137 | * information being correct. | |
138 | */ | |
139 | void | |
140 | png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height, | |
141 | int bit_depth, int color_type, int compression_type, int filter_type, | |
142 | int interlace_type) | |
143 | { | |
144 | png_byte buf[13]; /* buffer to store the IHDR info */ | |
145 | ||
146 | png_debug(1, "in png_write_IHDR\n"); | |
147 | /* Check that we have valid input data from the application info */ | |
148 | switch (color_type) | |
149 | { | |
150 | case PNG_COLOR_TYPE_GRAY: | |
151 | switch (bit_depth) | |
152 | { | |
153 | case 1: | |
154 | case 2: | |
155 | case 4: | |
156 | case 8: | |
157 | case 16: png_ptr->channels = 1; break; | |
158 | default: png_error(png_ptr,"Invalid bit depth for grayscale image"); | |
159 | } | |
160 | break; | |
161 | case PNG_COLOR_TYPE_RGB: | |
162 | if (bit_depth != 8 && bit_depth != 16) | |
163 | png_error(png_ptr, "Invalid bit depth for RGB image"); | |
164 | png_ptr->channels = 3; | |
165 | break; | |
166 | case PNG_COLOR_TYPE_PALETTE: | |
167 | switch (bit_depth) | |
168 | { | |
169 | case 1: | |
170 | case 2: | |
171 | case 4: | |
172 | case 8: png_ptr->channels = 1; break; | |
173 | default: png_error(png_ptr, "Invalid bit depth for paletted image"); | |
174 | } | |
175 | break; | |
176 | case PNG_COLOR_TYPE_GRAY_ALPHA: | |
177 | if (bit_depth != 8 && bit_depth != 16) | |
178 | png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); | |
179 | png_ptr->channels = 2; | |
180 | break; | |
181 | case PNG_COLOR_TYPE_RGB_ALPHA: | |
182 | if (bit_depth != 8 && bit_depth != 16) | |
183 | png_error(png_ptr, "Invalid bit depth for RGBA image"); | |
184 | png_ptr->channels = 4; | |
185 | break; | |
186 | default: | |
187 | png_error(png_ptr, "Invalid image color type specified"); | |
188 | } | |
189 | ||
190 | if (compression_type != PNG_COMPRESSION_TYPE_BASE) | |
191 | { | |
192 | png_warning(png_ptr, "Invalid compression type specified"); | |
193 | compression_type = PNG_COMPRESSION_TYPE_BASE; | |
194 | } | |
195 | ||
196 | if (filter_type != PNG_FILTER_TYPE_BASE) | |
197 | { | |
198 | png_warning(png_ptr, "Invalid filter type specified"); | |
199 | filter_type = PNG_FILTER_TYPE_BASE; | |
200 | } | |
201 | ||
202 | #ifdef PNG_WRITE_INTERLACING_SUPPORTED | |
203 | if (interlace_type != PNG_INTERLACE_NONE && | |
204 | interlace_type != PNG_INTERLACE_ADAM7) | |
205 | { | |
206 | png_warning(png_ptr, "Invalid interlace type specified"); | |
207 | interlace_type = PNG_INTERLACE_ADAM7; | |
208 | } | |
209 | #else | |
210 | interlace_type=PNG_INTERLACE_NONE; | |
211 | #endif | |
212 | ||
213 | /* save off the relevent information */ | |
214 | png_ptr->bit_depth = (png_byte)bit_depth; | |
215 | png_ptr->color_type = (png_byte)color_type; | |
216 | png_ptr->interlaced = (png_byte)interlace_type; | |
217 | png_ptr->width = width; | |
218 | png_ptr->height = height; | |
219 | ||
220 | png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels); | |
221 | png_ptr->rowbytes = ((width * (png_size_t)png_ptr->pixel_depth + 7) >> 3); | |
222 | /* set the usr info, so any transformations can modify it */ | |
223 | png_ptr->usr_width = png_ptr->width; | |
224 | png_ptr->usr_bit_depth = png_ptr->bit_depth; | |
225 | png_ptr->usr_channels = png_ptr->channels; | |
226 | ||
227 | /* pack the header information into the buffer */ | |
228 | png_save_uint_32(buf, width); | |
229 | png_save_uint_32(buf + 4, height); | |
230 | buf[8] = (png_byte)bit_depth; | |
231 | buf[9] = (png_byte)color_type; | |
232 | buf[10] = (png_byte)compression_type; | |
233 | buf[11] = (png_byte)filter_type; | |
234 | buf[12] = (png_byte)interlace_type; | |
235 | ||
236 | /* write the chunk */ | |
237 | png_write_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); | |
238 | ||
239 | /* initialize zlib with PNG info */ | |
240 | png_ptr->zstream.zalloc = png_zalloc; | |
241 | png_ptr->zstream.zfree = png_zfree; | |
242 | png_ptr->zstream.opaque = (voidpf)png_ptr; | |
243 | if (!(png_ptr->do_filter)) | |
244 | { | |
245 | if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || | |
246 | png_ptr->bit_depth < 8) | |
247 | png_ptr->do_filter = PNG_FILTER_NONE; | |
248 | else | |
249 | png_ptr->do_filter = PNG_ALL_FILTERS; | |
250 | } | |
251 | if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)) | |
252 | { | |
253 | if (png_ptr->do_filter != PNG_FILTER_NONE) | |
254 | png_ptr->zlib_strategy = Z_FILTERED; | |
255 | else | |
256 | png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY; | |
257 | } | |
258 | if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL)) | |
259 | png_ptr->zlib_level = Z_DEFAULT_COMPRESSION; | |
260 | if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL)) | |
261 | png_ptr->zlib_mem_level = 8; | |
262 | if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS)) | |
263 | png_ptr->zlib_window_bits = 15; | |
264 | if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD)) | |
265 | png_ptr->zlib_method = 8; | |
266 | deflateInit2(&png_ptr->zstream, png_ptr->zlib_level, | |
267 | png_ptr->zlib_method, png_ptr->zlib_window_bits, | |
268 | png_ptr->zlib_mem_level, png_ptr->zlib_strategy); | |
269 | png_ptr->zstream.next_out = png_ptr->zbuf; | |
270 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
271 | ||
272 | png_ptr->mode = PNG_HAVE_IHDR; | |
273 | } | |
274 | ||
275 | /* write the palette. We are careful not to trust png_color to be in the | |
a626cc03 | 276 | * correct order for PNG, so people can redefine it to any convenient |
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277 | * structure. |
278 | */ | |
279 | void | |
280 | png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal) | |
281 | { | |
282 | png_uint_32 i; | |
283 | png_colorp pal_ptr; | |
284 | png_byte buf[3]; | |
285 | ||
286 | png_debug(1, "in png_write_PLTE\n"); | |
287 | if (num_pal == 0 || num_pal > 256) | |
288 | { | |
289 | if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) | |
290 | { | |
291 | png_error(png_ptr, "Invalid number of colors in palette"); | |
292 | } | |
293 | else | |
294 | { | |
295 | png_warning(png_ptr, "Invalid number of colors in palette"); | |
296 | return; | |
297 | } | |
298 | } | |
299 | ||
300 | png_ptr->num_palette = (png_uint_16)num_pal; | |
301 | png_debug1(3, "num_palette = %d\n", png_ptr->num_palette); | |
302 | ||
303 | png_write_chunk_start(png_ptr, png_PLTE, num_pal * 3); | |
304 | for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) | |
305 | { | |
306 | buf[0] = pal_ptr->red; | |
307 | buf[1] = pal_ptr->green; | |
308 | buf[2] = pal_ptr->blue; | |
309 | png_write_chunk_data(png_ptr, buf, (png_size_t)3); | |
310 | } | |
311 | png_write_chunk_end(png_ptr); | |
312 | png_ptr->mode |= PNG_HAVE_PLTE; | |
313 | } | |
314 | ||
315 | /* write an IDAT chunk */ | |
316 | void | |
317 | png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length) | |
318 | { | |
319 | png_debug(1, "in png_write_IDAT\n"); | |
320 | png_write_chunk(png_ptr, png_IDAT, data, length); | |
321 | png_ptr->mode |= PNG_HAVE_IDAT; | |
322 | } | |
323 | ||
324 | /* write an IEND chunk */ | |
325 | void | |
326 | png_write_IEND(png_structp png_ptr) | |
327 | { | |
328 | png_debug(1, "in png_write_IEND\n"); | |
329 | png_write_chunk(png_ptr, png_IEND, NULL, (png_size_t)0); | |
330 | png_ptr->mode |= PNG_HAVE_IEND; | |
331 | } | |
332 | ||
333 | #if defined(PNG_WRITE_gAMA_SUPPORTED) | |
334 | /* write a gAMA chunk */ | |
335 | void | |
336 | png_write_gAMA(png_structp png_ptr, double file_gamma) | |
337 | { | |
338 | png_uint_32 igamma; | |
339 | png_byte buf[4]; | |
340 | ||
341 | png_debug(1, "in png_write_gAMA\n"); | |
342 | /* file_gamma is saved in 1/1000000ths */ | |
343 | igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5); | |
344 | png_save_uint_32(buf, igamma); | |
345 | png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); | |
346 | } | |
347 | #endif | |
348 | ||
349 | #if defined(PNG_WRITE_sRGB_SUPPORTED) | |
350 | /* write a sRGB chunk */ | |
351 | void | |
352 | png_write_sRGB(png_structp png_ptr, int srgb_intent) | |
353 | { | |
354 | png_byte buf[1]; | |
355 | ||
356 | png_debug(1, "in png_write_sRGB\n"); | |
357 | if(srgb_intent >= PNG_sRGB_INTENT_LAST) | |
358 | png_warning(png_ptr, | |
359 | "Invalid sRGB rendering intent specified"); | |
360 | buf[0]=(png_byte)srgb_intent; | |
361 | png_write_chunk(png_ptr, png_sRGB, buf, (png_size_t)1); | |
362 | } | |
363 | #endif | |
364 | ||
365 | #if defined(PNG_WRITE_sBIT_SUPPORTED) | |
366 | /* write the sBIT chunk */ | |
367 | void | |
368 | png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type) | |
369 | { | |
370 | png_byte buf[4]; | |
371 | png_size_t size; | |
372 | ||
373 | png_debug(1, "in png_write_sBIT\n"); | |
374 | /* make sure we don't depend upon the order of PNG_COLOR_8 */ | |
375 | if (color_type & PNG_COLOR_MASK_COLOR) | |
376 | { | |
377 | png_byte maxbits; | |
378 | ||
a626cc03 RR |
379 | maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8 : png_ptr->usr_bit_depth; |
380 | if (sbit->red == 0 || sbit->red > maxbits || | |
381 | sbit->green == 0 || sbit->green > maxbits || | |
c801d85f KB |
382 | sbit->blue == 0 || sbit->blue > maxbits) |
383 | { | |
384 | png_warning(png_ptr, "Invalid sBIT depth specified"); | |
385 | return; | |
386 | } | |
387 | buf[0] = sbit->red; | |
388 | buf[1] = sbit->green; | |
389 | buf[2] = sbit->blue; | |
390 | size = 3; | |
391 | } | |
392 | else | |
393 | { | |
394 | if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth) | |
395 | { | |
396 | png_warning(png_ptr, "Invalid sBIT depth specified"); | |
397 | return; | |
398 | } | |
399 | buf[0] = sbit->gray; | |
400 | size = 1; | |
401 | } | |
402 | ||
403 | if (color_type & PNG_COLOR_MASK_ALPHA) | |
404 | { | |
405 | if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth) | |
406 | { | |
407 | png_warning(png_ptr, "Invalid sBIT depth specified"); | |
408 | return; | |
409 | } | |
410 | buf[size++] = sbit->alpha; | |
411 | } | |
412 | ||
413 | png_write_chunk(png_ptr, png_sBIT, buf, size); | |
414 | } | |
415 | #endif | |
416 | ||
417 | #if defined(PNG_WRITE_cHRM_SUPPORTED) | |
418 | /* write the cHRM chunk */ | |
419 | void | |
420 | png_write_cHRM(png_structp png_ptr, double white_x, double white_y, | |
421 | double red_x, double red_y, double green_x, double green_y, | |
422 | double blue_x, double blue_y) | |
423 | { | |
424 | png_uint_32 itemp; | |
425 | png_byte buf[32]; | |
426 | ||
427 | png_debug(1, "in png_write_cHRM\n"); | |
428 | /* each value is saved int 1/1000000ths */ | |
429 | if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 || | |
430 | white_x + white_y > 1.0) | |
431 | { | |
432 | png_warning(png_ptr, "Invalid cHRM white point specified"); | |
433 | return; | |
434 | } | |
435 | itemp = (png_uint_32)(white_x * 100000.0 + 0.5); | |
436 | png_save_uint_32(buf, itemp); | |
437 | itemp = (png_uint_32)(white_y * 100000.0 + 0.5); | |
438 | png_save_uint_32(buf + 4, itemp); | |
439 | ||
440 | if (red_x < 0 || red_x > 0.8 || red_y < 0 || red_y > 0.8 || | |
441 | red_x + red_y > 1.0) | |
442 | { | |
443 | png_warning(png_ptr, "Invalid cHRM red point specified"); | |
444 | return; | |
445 | } | |
446 | itemp = (png_uint_32)(red_x * 100000.0 + 0.5); | |
447 | png_save_uint_32(buf + 8, itemp); | |
448 | itemp = (png_uint_32)(red_y * 100000.0 + 0.5); | |
449 | png_save_uint_32(buf + 12, itemp); | |
450 | ||
451 | if (green_x < 0 || green_x > 0.8 || green_y < 0 || green_y > 0.8 || | |
452 | green_x + green_y > 1.0) | |
453 | { | |
454 | png_warning(png_ptr, "Invalid cHRM green point specified"); | |
455 | return; | |
456 | } | |
457 | itemp = (png_uint_32)(green_x * 100000.0 + 0.5); | |
458 | png_save_uint_32(buf + 16, itemp); | |
459 | itemp = (png_uint_32)(green_y * 100000.0 + 0.5); | |
460 | png_save_uint_32(buf + 20, itemp); | |
461 | ||
462 | if (blue_x < 0 || blue_x > 0.8 || blue_y < 0 || blue_y > 0.8 || | |
463 | blue_x + blue_y > 1.0) | |
464 | { | |
465 | png_warning(png_ptr, "Invalid cHRM blue point specified"); | |
466 | return; | |
467 | } | |
468 | itemp = (png_uint_32)(blue_x * 100000.0 + 0.5); | |
469 | png_save_uint_32(buf + 24, itemp); | |
470 | itemp = (png_uint_32)(blue_y * 100000.0 + 0.5); | |
471 | png_save_uint_32(buf + 28, itemp); | |
472 | ||
473 | png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32); | |
474 | } | |
475 | #endif | |
476 | ||
477 | #if defined(PNG_WRITE_tRNS_SUPPORTED) | |
478 | /* write the tRNS chunk */ | |
479 | void | |
480 | png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran, | |
481 | int num_trans, int color_type) | |
482 | { | |
483 | png_byte buf[6]; | |
484 | ||
485 | png_debug(1, "in png_write_tRNS\n"); | |
486 | if (color_type == PNG_COLOR_TYPE_PALETTE) | |
487 | { | |
488 | if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) | |
489 | { | |
490 | png_warning(png_ptr,"Invalid number of transparent colors specified"); | |
491 | return; | |
492 | } | |
493 | /* write the chunk out as it is */ | |
494 | png_write_chunk(png_ptr, png_tRNS, trans, (png_size_t)num_trans); | |
495 | } | |
496 | else if (color_type == PNG_COLOR_TYPE_GRAY) | |
497 | { | |
498 | /* one 16 bit value */ | |
499 | png_save_uint_16(buf, tran->gray); | |
500 | png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)2); | |
501 | } | |
502 | else if (color_type == PNG_COLOR_TYPE_RGB) | |
503 | { | |
504 | /* three 16 bit values */ | |
505 | png_save_uint_16(buf, tran->red); | |
506 | png_save_uint_16(buf + 2, tran->green); | |
507 | png_save_uint_16(buf + 4, tran->blue); | |
508 | png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); | |
509 | } | |
510 | else | |
511 | { | |
512 | png_warning(png_ptr, "Can't write tRNS with an alpha channel"); | |
513 | } | |
514 | } | |
515 | #endif | |
516 | ||
517 | #if defined(PNG_WRITE_bKGD_SUPPORTED) | |
518 | /* write the background chunk */ | |
519 | void | |
520 | png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type) | |
521 | { | |
522 | png_byte buf[6]; | |
523 | ||
524 | png_debug(1, "in png_write_bKGD\n"); | |
525 | if (color_type == PNG_COLOR_TYPE_PALETTE) | |
526 | { | |
527 | if (back->index > png_ptr->num_palette) | |
528 | { | |
529 | png_warning(png_ptr, "Invalid background palette index"); | |
530 | return; | |
531 | } | |
532 | buf[0] = back->index; | |
533 | png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)1); | |
534 | } | |
535 | else if (color_type & PNG_COLOR_MASK_COLOR) | |
536 | { | |
537 | png_save_uint_16(buf, back->red); | |
538 | png_save_uint_16(buf + 2, back->green); | |
539 | png_save_uint_16(buf + 4, back->blue); | |
540 | png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)6); | |
541 | } | |
542 | else | |
543 | { | |
544 | png_save_uint_16(buf, back->gray); | |
545 | png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)2); | |
546 | } | |
547 | } | |
548 | #endif | |
549 | ||
550 | #if defined(PNG_WRITE_hIST_SUPPORTED) | |
551 | /* write the histogram */ | |
552 | void | |
553 | png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist) | |
554 | { | |
555 | int i; | |
556 | png_byte buf[3]; | |
557 | ||
558 | png_debug(1, "in png_write_hIST\n"); | |
559 | if (num_hist > (int)png_ptr->num_palette) | |
560 | { | |
561 | png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist, | |
562 | png_ptr->num_palette); | |
563 | png_warning(png_ptr, "Invalid number of histogram entries specified"); | |
564 | return; | |
565 | } | |
566 | ||
567 | png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(num_hist * 2)); | |
568 | for (i = 0; i < num_hist; i++) | |
569 | { | |
570 | png_save_uint_16(buf, hist[i]); | |
571 | png_write_chunk_data(png_ptr, buf, (png_size_t)2); | |
572 | } | |
573 | png_write_chunk_end(png_ptr); | |
574 | } | |
575 | #endif | |
576 | ||
a626cc03 RR |
577 | #if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED) || \ |
578 | defined(PNG_WRITE_pCAL_SUPPORTED) | |
c801d85f KB |
579 | /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification, |
580 | * and if invalid, correct the keyword rather than discarding the entire | |
581 | * chunk. The PNG 1.0 specification requires keywords 1-79 characters in | |
582 | * length, forbids leading or trailing whitespace, multiple internal spaces, | |
583 | * and the non-break space (0x80) from ISO 8859-1. Returns keyword length. | |
584 | * | |
585 | * The new_key is allocated to hold the corrected keyword and must be freed | |
586 | * by the calling routine. This avoids problems with trying to write to | |
587 | * static keywords without having to have duplicate copies of the strings. | |
588 | */ | |
589 | png_size_t | |
590 | png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key) | |
591 | { | |
592 | png_size_t key_len; | |
593 | png_charp kp, dp; | |
594 | int kflag; | |
595 | ||
596 | png_debug(1, "in png_check_keyword\n"); | |
597 | *new_key = NULL; | |
598 | ||
599 | if (key == NULL || (key_len = png_strlen(key)) == 0) | |
600 | { | |
601 | png_chunk_warning(png_ptr, "zero length keyword"); | |
602 | return ((png_size_t)0); | |
603 | } | |
604 | ||
605 | png_debug1(2, "Keyword to be checked is '%s'\n", key); | |
606 | ||
607 | *new_key = (png_charp)png_malloc(png_ptr, (png_uint_32)(key_len + 1)); | |
608 | ||
609 | /* Replace non-printing characters with a blank and print a warning */ | |
610 | for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++) | |
611 | { | |
612 | if (*kp < 0x20 || (*kp > 0x7E && (png_byte)*kp < 0xA1)) | |
613 | { | |
614 | #if !defined(PNG_NO_STDIO) | |
615 | char msg[40]; | |
616 | ||
617 | sprintf(msg, "invalid keyword character 0x%02X", *kp); | |
618 | png_chunk_warning(png_ptr, msg); | |
619 | #else | |
620 | png_chunk_warning(png_ptr, "invalid character in keyword"); | |
621 | #endif | |
622 | *dp = ' '; | |
623 | } | |
624 | else | |
625 | { | |
626 | *dp = *kp; | |
627 | } | |
628 | } | |
629 | *dp = '\0'; | |
630 | ||
631 | /* Remove any trailing white space. */ | |
632 | kp = *new_key + key_len - 1; | |
633 | if (*kp == ' ') | |
634 | { | |
635 | png_chunk_warning(png_ptr, "trailing spaces removed from keyword"); | |
636 | ||
637 | while (*kp == ' ') | |
638 | { | |
639 | *(kp--) = '\0'; | |
640 | key_len--; | |
641 | } | |
642 | } | |
643 | ||
644 | /* Remove any leading white space. */ | |
645 | kp = *new_key; | |
646 | if (*kp == ' ') | |
647 | { | |
648 | png_chunk_warning(png_ptr, "leading spaces removed from keyword"); | |
649 | ||
650 | while (*kp == ' ') | |
651 | { | |
652 | kp++; | |
653 | key_len--; | |
654 | } | |
655 | } | |
656 | ||
657 | png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp); | |
658 | ||
659 | /* Remove multiple internal spaces. */ | |
660 | for (kflag = 0, dp = *new_key; *kp != '\0'; kp++) | |
661 | { | |
662 | if (*kp == ' ' && kflag == 0) | |
663 | { | |
664 | *(dp++) = *kp; | |
665 | kflag = 1; | |
666 | } | |
667 | else if (*kp == ' ') | |
668 | { | |
669 | key_len--; | |
670 | } | |
671 | else | |
672 | { | |
673 | *(dp++) = *kp; | |
674 | kflag = 0; | |
675 | } | |
676 | } | |
677 | *dp = '\0'; | |
678 | ||
679 | if (key_len == 0) | |
680 | { | |
681 | png_chunk_warning(png_ptr, "zero length keyword"); | |
682 | } | |
683 | ||
684 | if (key_len > 79) | |
685 | { | |
686 | png_chunk_warning(png_ptr, "keyword length must be 1 - 79 characters"); | |
687 | new_key[79] = '\0'; | |
688 | key_len = 79; | |
689 | } | |
690 | ||
691 | return (key_len); | |
692 | } | |
693 | #endif | |
694 | ||
695 | #if defined(PNG_WRITE_tEXt_SUPPORTED) | |
696 | /* write a tEXt chunk */ | |
697 | void | |
698 | png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text, | |
699 | png_size_t text_len) | |
700 | { | |
701 | png_size_t key_len; | |
702 | png_charp new_key; | |
703 | ||
704 | png_debug(1, "in png_write_tEXt\n"); | |
705 | if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0) | |
706 | { | |
707 | png_warning(png_ptr, "Empty keyword in tEXt chunk"); | |
708 | return; | |
709 | } | |
710 | ||
711 | if (text == NULL || *text == '\0') | |
712 | text_len = 0; | |
713 | ||
714 | /* make sure we include the 0 after the key */ | |
715 | png_write_chunk_start(png_ptr, png_tEXt, (png_uint_32)key_len+text_len+1); | |
716 | png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1); | |
717 | if (text_len) | |
718 | png_write_chunk_data(png_ptr, (png_bytep)text, text_len); | |
719 | ||
720 | png_write_chunk_end(png_ptr); | |
721 | png_free(png_ptr, new_key); | |
722 | } | |
723 | #endif | |
724 | ||
725 | #if defined(PNG_WRITE_zTXt_SUPPORTED) | |
726 | /* write a compressed text chunk */ | |
727 | void | |
728 | png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text, | |
729 | png_size_t text_len, int compression) | |
730 | { | |
731 | png_size_t key_len; | |
732 | char buf[1]; | |
733 | png_charp new_key; | |
734 | int i, ret; | |
735 | png_charpp output_ptr = NULL; /* array of pointers to output */ | |
736 | int num_output_ptr = 0; /* number of output pointers used */ | |
737 | int max_output_ptr = 0; /* size of output_ptr */ | |
738 | ||
739 | png_debug(1, "in png_write_zTXt\n"); | |
740 | ||
741 | if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0) | |
742 | { | |
743 | png_warning(png_ptr, "Empty keyword in zTXt chunk"); | |
744 | return; | |
745 | } | |
746 | ||
747 | if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE) | |
748 | { | |
749 | png_write_tEXt(png_ptr, new_key, text, (png_size_t)0); | |
750 | png_free(png_ptr, new_key); | |
751 | return; | |
752 | } | |
753 | ||
754 | png_free(png_ptr, new_key); | |
755 | ||
756 | if (compression >= PNG_TEXT_COMPRESSION_LAST) | |
757 | { | |
758 | #if !defined(PNG_NO_STDIO) | |
759 | char msg[50]; | |
760 | sprintf(msg, "Unknown zTXt compression type %d", compression); | |
761 | png_warning(png_ptr, msg); | |
762 | #else | |
763 | png_warning(png_ptr, "Unknown zTXt compression type"); | |
764 | #endif | |
765 | compression = PNG_TEXT_COMPRESSION_zTXt; | |
766 | } | |
767 | ||
768 | /* We can't write the chunk until we find out how much data we have, | |
a626cc03 | 769 | * which means we need to run the compressor first and save the |
c801d85f KB |
770 | * output. This shouldn't be a problem, as the vast majority of |
771 | * comments should be reasonable, but we will set up an array of | |
772 | * malloc'd pointers to be sure. | |
773 | * | |
774 | * If we knew the application was well behaved, we could simplify this | |
775 | * greatly by assuming we can always malloc an output buffer large | |
776 | * enough to hold the compressed text ((1001 * text_len / 1000) + 12) | |
777 | * and malloc this directly. The only time this would be a bad idea is | |
778 | * if we can't malloc more than 64K and we have 64K of random input | |
779 | * data, or if the input string is incredibly large (although this | |
780 | * wouldn't cause a failure, just a slowdown due to swapping). | |
781 | */ | |
782 | ||
783 | /* set up the compression buffers */ | |
784 | png_ptr->zstream.avail_in = (uInt)text_len; | |
785 | png_ptr->zstream.next_in = (Bytef *)text; | |
786 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
787 | png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf; | |
788 | ||
789 | /* this is the same compression loop as in png_write_row() */ | |
790 | do | |
791 | { | |
792 | /* compress the data */ | |
793 | ret = deflate(&png_ptr->zstream, Z_NO_FLUSH); | |
794 | if (ret != Z_OK) | |
795 | { | |
796 | /* error */ | |
797 | if (png_ptr->zstream.msg != NULL) | |
798 | png_error(png_ptr, png_ptr->zstream.msg); | |
799 | else | |
800 | png_error(png_ptr, "zlib error"); | |
801 | } | |
802 | /* check to see if we need more room */ | |
803 | if (!png_ptr->zstream.avail_out && png_ptr->zstream.avail_in) | |
804 | { | |
805 | /* make sure the output array has room */ | |
806 | if (num_output_ptr >= max_output_ptr) | |
807 | { | |
808 | int old_max; | |
809 | ||
810 | old_max = max_output_ptr; | |
811 | max_output_ptr = num_output_ptr + 4; | |
812 | if (output_ptr != NULL) | |
813 | { | |
814 | png_charpp old_ptr; | |
815 | ||
816 | old_ptr = output_ptr; | |
817 | output_ptr = (png_charpp)png_malloc(png_ptr, | |
818 | (png_uint_32)(max_output_ptr * sizeof (png_charpp))); | |
819 | png_memcpy(output_ptr, old_ptr, old_max * sizeof (png_charp)); | |
820 | png_free(png_ptr, old_ptr); | |
821 | } | |
822 | else | |
823 | output_ptr = (png_charpp)png_malloc(png_ptr, | |
824 | (png_uint_32)(max_output_ptr * sizeof (png_charp))); | |
825 | } | |
826 | ||
827 | /* save the data */ | |
828 | output_ptr[num_output_ptr] = (png_charp)png_malloc(png_ptr, | |
829 | (png_uint_32)png_ptr->zbuf_size); | |
830 | png_memcpy(output_ptr[num_output_ptr], png_ptr->zbuf, | |
831 | png_ptr->zbuf_size); | |
832 | num_output_ptr++; | |
833 | ||
834 | /* and reset the buffer */ | |
835 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
836 | png_ptr->zstream.next_out = png_ptr->zbuf; | |
837 | } | |
a626cc03 | 838 | /* continue until we don't have any more to compress */ |
c801d85f KB |
839 | } while (png_ptr->zstream.avail_in); |
840 | ||
841 | /* finish the compression */ | |
842 | do | |
843 | { | |
844 | /* tell zlib we are finished */ | |
845 | ret = deflate(&png_ptr->zstream, Z_FINISH); | |
846 | if (ret != Z_OK && ret != Z_STREAM_END) | |
847 | { | |
848 | /* we got an error */ | |
849 | if (png_ptr->zstream.msg != NULL) | |
850 | png_error(png_ptr, png_ptr->zstream.msg); | |
851 | else | |
852 | png_error(png_ptr, "zlib error"); | |
853 | } | |
854 | ||
855 | /* check to see if we need more room */ | |
856 | if (!(png_ptr->zstream.avail_out) && ret == Z_OK) | |
857 | { | |
858 | /* check to make sure our output array has room */ | |
859 | if (num_output_ptr >= max_output_ptr) | |
860 | { | |
861 | int old_max; | |
862 | ||
863 | old_max = max_output_ptr; | |
864 | max_output_ptr = num_output_ptr + 4; | |
865 | if (output_ptr != NULL) | |
866 | { | |
867 | png_charpp old_ptr; | |
868 | ||
869 | old_ptr = output_ptr; | |
870 | /* This could be optimized to realloc() */ | |
871 | output_ptr = (png_charpp)png_malloc(png_ptr, | |
872 | (png_uint_32)(max_output_ptr * sizeof (png_charpp))); | |
873 | png_memcpy(output_ptr, old_ptr, old_max * sizeof (png_charp)); | |
874 | png_free(png_ptr, old_ptr); | |
875 | } | |
876 | else | |
877 | output_ptr = (png_charpp)png_malloc(png_ptr, | |
878 | (png_uint_32)(max_output_ptr * sizeof (png_charp))); | |
879 | } | |
880 | ||
881 | /* save off the data */ | |
882 | output_ptr[num_output_ptr] = (png_charp)png_malloc(png_ptr, | |
883 | (png_uint_32)png_ptr->zbuf_size); | |
884 | png_memcpy(output_ptr[num_output_ptr], png_ptr->zbuf, | |
885 | png_ptr->zbuf_size); | |
886 | num_output_ptr++; | |
887 | ||
888 | /* and reset the buffer pointers */ | |
889 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
890 | png_ptr->zstream.next_out = png_ptr->zbuf; | |
891 | } | |
892 | } while (ret != Z_STREAM_END); | |
893 | ||
894 | /* text length is number of buffers plus last buffer */ | |
895 | text_len = png_ptr->zbuf_size * num_output_ptr; | |
896 | if (png_ptr->zstream.avail_out < png_ptr->zbuf_size) | |
897 | text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out; | |
898 | ||
899 | /* write start of chunk */ | |
900 | png_write_chunk_start(png_ptr, png_zTXt, (png_uint_32)(key_len+text_len+2)); | |
901 | /* write key */ | |
902 | png_write_chunk_data(png_ptr, (png_bytep)key, key_len + 1); | |
903 | buf[0] = (png_byte)compression; | |
904 | /* write compression */ | |
905 | png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1); | |
906 | ||
907 | /* write saved output buffers, if any */ | |
908 | for (i = 0; i < num_output_ptr; i++) | |
909 | { | |
910 | png_write_chunk_data(png_ptr,(png_bytep)output_ptr[i],png_ptr->zbuf_size); | |
911 | png_free(png_ptr, output_ptr[i]); | |
912 | } | |
913 | if (max_output_ptr != 0) | |
914 | png_free(png_ptr, output_ptr); | |
915 | /* write anything left in zbuf */ | |
916 | if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size) | |
917 | png_write_chunk_data(png_ptr, png_ptr->zbuf, | |
918 | png_ptr->zbuf_size - png_ptr->zstream.avail_out); | |
919 | /* close the chunk */ | |
920 | png_write_chunk_end(png_ptr); | |
921 | ||
922 | /* reset zlib for another zTXt or the image data */ | |
923 | deflateReset(&png_ptr->zstream); | |
924 | } | |
925 | #endif | |
926 | ||
927 | ||
928 | #if defined(PNG_WRITE_oFFs_SUPPORTED) | |
929 | /* write the oFFs chunk */ | |
930 | void | |
931 | png_write_oFFs(png_structp png_ptr, png_uint_32 x_offset, | |
932 | png_uint_32 y_offset, | |
933 | int unit_type) | |
934 | { | |
935 | png_byte buf[9]; | |
936 | ||
937 | png_debug(1, "in png_write_oFFs\n"); | |
938 | if (unit_type >= PNG_OFFSET_LAST) | |
939 | png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); | |
940 | ||
941 | png_save_uint_32(buf, x_offset); | |
942 | png_save_uint_32(buf + 4, y_offset); | |
943 | buf[8] = (png_byte)unit_type; | |
944 | ||
945 | png_write_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); | |
946 | } | |
947 | #endif | |
948 | ||
949 | #if defined(PNG_WRITE_pCAL_SUPPORTED) | |
950 | /* write the pCAL chunk (png-scivis-19970203) */ | |
951 | void | |
952 | png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0, | |
953 | png_int_32 X1, int type, int nparams, png_charp units, png_charpp params) | |
954 | { | |
a626cc03 | 955 | png_size_t purpose_len, units_len, total_len; |
c801d85f KB |
956 | png_uint_32p params_len; |
957 | png_byte buf[10]; | |
958 | png_charp new_purpose; | |
959 | int i; | |
960 | ||
961 | png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams); | |
962 | if (type >= PNG_EQUATION_LAST) | |
963 | png_warning(png_ptr, "Unrecognized equation type for pCAL chunk"); | |
964 | ||
965 | purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1; | |
966 | png_debug1(3, "pCAL purpose length = %d\n", purpose_len); | |
967 | units_len = png_strlen(units) + (nparams == 0 ? 0 : 1); | |
968 | png_debug1(3, "pCAL units length = %d\n", units_len); | |
969 | total_len = purpose_len + units_len + 10; | |
970 | ||
971 | params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams | |
972 | *sizeof(png_uint_32))); | |
973 | ||
974 | /* Find the length of each parameter, making sure we don't count the | |
975 | null terminator for the last parameter. */ | |
976 | for (i = 0; i < nparams; i++) | |
977 | { | |
978 | params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1); | |
979 | png_debug2(3, "pCAL parameter %d length = %d\n", i, params_len[i]); | |
980 | total_len += (png_size_t)params_len[i]; | |
981 | } | |
982 | ||
983 | png_debug1(3, "pCAL total length = %d\n", total_len); | |
984 | png_write_chunk_start(png_ptr, png_pCAL, (png_uint_32)total_len); | |
985 | png_write_chunk_data(png_ptr, (png_bytep)new_purpose, purpose_len); | |
986 | png_save_int_32(buf, X0); | |
987 | png_save_int_32(buf + 4, X1); | |
988 | buf[8] = (png_byte)type; | |
989 | buf[9] = (png_byte)nparams; | |
990 | png_write_chunk_data(png_ptr, buf, (png_size_t)10); | |
991 | png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len); | |
992 | ||
993 | png_free(png_ptr, new_purpose); | |
994 | ||
995 | for (i = 0; i < nparams; i++) | |
996 | { | |
997 | png_write_chunk_data(png_ptr, (png_bytep)params[i], | |
998 | (png_size_t)params_len[i]); | |
999 | } | |
1000 | ||
1001 | png_free(png_ptr, params_len); | |
1002 | png_write_chunk_end(png_ptr); | |
1003 | } | |
1004 | #endif | |
1005 | ||
1006 | #if defined(PNG_WRITE_pHYs_SUPPORTED) | |
1007 | /* write the pHYs chunk */ | |
1008 | void | |
1009 | png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit, | |
1010 | png_uint_32 y_pixels_per_unit, | |
1011 | int unit_type) | |
1012 | { | |
1013 | png_byte buf[9]; | |
1014 | ||
1015 | png_debug(1, "in png_write_pHYs\n"); | |
1016 | if (unit_type >= PNG_RESOLUTION_LAST) | |
1017 | png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); | |
1018 | ||
1019 | png_save_uint_32(buf, x_pixels_per_unit); | |
1020 | png_save_uint_32(buf + 4, y_pixels_per_unit); | |
1021 | buf[8] = (png_byte)unit_type; | |
1022 | ||
1023 | png_write_chunk(png_ptr, png_pHYs, buf, (png_size_t)9); | |
1024 | } | |
1025 | #endif | |
1026 | ||
1027 | #if defined(PNG_WRITE_tIME_SUPPORTED) | |
1028 | /* Write the tIME chunk. Use either png_convert_from_struct_tm() | |
1029 | * or png_convert_from_time_t(), or fill in the structure yourself. | |
1030 | */ | |
1031 | void | |
1032 | png_write_tIME(png_structp png_ptr, png_timep mod_time) | |
1033 | { | |
1034 | png_byte buf[7]; | |
1035 | ||
1036 | png_debug(1, "in png_write_tIME\n"); | |
1037 | if (mod_time->month > 12 || mod_time->month < 1 || | |
1038 | mod_time->day > 31 || mod_time->day < 1 || | |
1039 | mod_time->hour > 23 || mod_time->second > 60) | |
1040 | { | |
1041 | png_warning(png_ptr, "Invalid time specified for tIME chunk"); | |
1042 | return; | |
1043 | } | |
1044 | ||
1045 | png_save_uint_16(buf, mod_time->year); | |
1046 | buf[2] = mod_time->month; | |
1047 | buf[3] = mod_time->day; | |
1048 | buf[4] = mod_time->hour; | |
1049 | buf[5] = mod_time->minute; | |
1050 | buf[6] = mod_time->second; | |
1051 | ||
1052 | png_write_chunk(png_ptr, png_tIME, buf, (png_size_t)7); | |
1053 | } | |
1054 | #endif | |
1055 | ||
1056 | /* initializes the row writing capability of libpng */ | |
1057 | void | |
1058 | png_write_start_row(png_structp png_ptr) | |
1059 | { | |
1060 | png_size_t buf_size; | |
1061 | ||
1062 | png_debug(1, "in png_write_start_row\n"); | |
1063 | buf_size = (png_size_t)(((png_ptr->width * png_ptr->usr_channels * | |
1064 | png_ptr->usr_bit_depth + 7) >> 3) + 1); | |
1065 | ||
1066 | /* set up row buffer */ | |
1067 | png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size); | |
1068 | png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; | |
1069 | ||
1070 | /* set up filtering buffer, if using this filter */ | |
1071 | if (png_ptr->do_filter & PNG_FILTER_SUB) | |
1072 | { | |
1073 | png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, | |
1074 | (png_ptr->rowbytes + 1)); | |
1075 | png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB; | |
1076 | } | |
1077 | ||
1078 | /* We only need to keep the previous row if we are using one of these. */ | |
1079 | if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) | |
1080 | { | |
1081 | /* set up previous row buffer */ | |
1082 | png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size); | |
1083 | png_memset(png_ptr->prev_row, 0, buf_size); | |
1084 | ||
1085 | if (png_ptr->do_filter & PNG_FILTER_UP) | |
1086 | { | |
1087 | png_ptr->up_row = (png_bytep )png_malloc(png_ptr, | |
1088 | (png_ptr->rowbytes + 1)); | |
1089 | png_ptr->up_row[0] = PNG_FILTER_VALUE_UP; | |
1090 | } | |
1091 | ||
1092 | if (png_ptr->do_filter & PNG_FILTER_AVG) | |
1093 | { | |
1094 | png_ptr->avg_row = (png_bytep)png_malloc(png_ptr, | |
1095 | (png_ptr->rowbytes + 1)); | |
1096 | png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG; | |
1097 | } | |
1098 | ||
1099 | if (png_ptr->do_filter & PNG_FILTER_PAETH) | |
1100 | { | |
1101 | png_ptr->paeth_row = (png_bytep )png_malloc(png_ptr, | |
1102 | (png_ptr->rowbytes + 1)); | |
1103 | png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH; | |
1104 | } | |
1105 | } | |
1106 | ||
1107 | #ifdef PNG_WRITE_INTERLACING_SUPPORTED | |
1108 | /* if interlaced, we need to set up width and height of pass */ | |
1109 | if (png_ptr->interlaced) | |
1110 | { | |
1111 | if (!(png_ptr->transformations & PNG_INTERLACE)) | |
1112 | { | |
1113 | png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - | |
1114 | png_pass_ystart[0]) / png_pass_yinc[0]; | |
1115 | png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 - | |
1116 | png_pass_start[0]) / png_pass_inc[0]; | |
1117 | } | |
1118 | else | |
1119 | { | |
1120 | png_ptr->num_rows = png_ptr->height; | |
1121 | png_ptr->usr_width = png_ptr->width; | |
1122 | } | |
1123 | } | |
1124 | else | |
1125 | #endif | |
1126 | { | |
1127 | png_ptr->num_rows = png_ptr->height; | |
1128 | png_ptr->usr_width = png_ptr->width; | |
1129 | } | |
1130 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
1131 | png_ptr->zstream.next_out = png_ptr->zbuf; | |
1132 | } | |
1133 | ||
1134 | /* Internal use only. Called when finished processing a row of data. */ | |
1135 | void | |
1136 | png_write_finish_row(png_structp png_ptr) | |
1137 | { | |
1138 | int ret; | |
1139 | ||
1140 | png_debug(1, "in png_write_finish_row\n"); | |
1141 | /* next row */ | |
1142 | png_ptr->row_number++; | |
1143 | ||
1144 | /* see if we are done */ | |
1145 | if (png_ptr->row_number < png_ptr->num_rows) | |
1146 | return; | |
1147 | ||
1148 | #ifdef PNG_WRITE_INTERLACING_SUPPORTED | |
1149 | /* if interlaced, go to next pass */ | |
1150 | if (png_ptr->interlaced) | |
1151 | { | |
1152 | png_ptr->row_number = 0; | |
1153 | if (png_ptr->transformations & PNG_INTERLACE) | |
1154 | { | |
1155 | png_ptr->pass++; | |
1156 | } | |
1157 | else | |
1158 | { | |
1159 | /* loop until we find a non-zero width or height pass */ | |
1160 | do | |
1161 | { | |
1162 | png_ptr->pass++; | |
1163 | if (png_ptr->pass >= 7) | |
1164 | break; | |
1165 | png_ptr->usr_width = (png_ptr->width + | |
1166 | png_pass_inc[png_ptr->pass] - 1 - | |
1167 | png_pass_start[png_ptr->pass]) / | |
1168 | png_pass_inc[png_ptr->pass]; | |
1169 | png_ptr->num_rows = (png_ptr->height + | |
1170 | png_pass_yinc[png_ptr->pass] - 1 - | |
1171 | png_pass_ystart[png_ptr->pass]) / | |
1172 | png_pass_yinc[png_ptr->pass]; | |
1173 | if (png_ptr->transformations & PNG_INTERLACE) | |
1174 | break; | |
1175 | } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); | |
1176 | ||
1177 | } | |
1178 | ||
1179 | /* reset the row above the image for the next pass */ | |
1180 | if (png_ptr->pass < 7) | |
1181 | { | |
1182 | if (png_ptr->prev_row != NULL) | |
a626cc03 | 1183 | png_memset(png_ptr->prev_row, 0, |
c801d85f KB |
1184 | (png_size_t) (((png_uint_32)png_ptr->usr_channels * |
1185 | (png_uint_32)png_ptr->usr_bit_depth * | |
1186 | png_ptr->width + 7) >> 3) + 1); | |
1187 | return; | |
1188 | } | |
1189 | } | |
1190 | #endif | |
1191 | ||
1192 | /* if we get here, we've just written the last row, so we need | |
1193 | to flush the compressor */ | |
1194 | do | |
1195 | { | |
1196 | /* tell the compressor we are done */ | |
1197 | ret = deflate(&png_ptr->zstream, Z_FINISH); | |
1198 | /* check for an error */ | |
1199 | if (ret != Z_OK && ret != Z_STREAM_END) | |
1200 | { | |
1201 | if (png_ptr->zstream.msg != NULL) | |
1202 | png_error(png_ptr, png_ptr->zstream.msg); | |
1203 | else | |
1204 | png_error(png_ptr, "zlib error"); | |
1205 | } | |
1206 | /* check to see if we need more room */ | |
1207 | if (!(png_ptr->zstream.avail_out) && ret == Z_OK) | |
1208 | { | |
1209 | png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); | |
1210 | png_ptr->zstream.next_out = png_ptr->zbuf; | |
1211 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
1212 | } | |
1213 | } while (ret != Z_STREAM_END); | |
1214 | ||
1215 | /* write any extra space */ | |
1216 | if (png_ptr->zstream.avail_out < png_ptr->zbuf_size) | |
1217 | { | |
1218 | png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size - | |
1219 | png_ptr->zstream.avail_out); | |
1220 | } | |
1221 | ||
1222 | deflateReset(&png_ptr->zstream); | |
1223 | } | |
1224 | ||
1225 | #if defined(PNG_WRITE_INTERLACING_SUPPORTED) | |
1226 | /* Pick out the correct pixels for the interlace pass. | |
1227 | * The basic idea here is to go through the row with a source | |
1228 | * pointer and a destination pointer (sp and dp), and copy the | |
1229 | * correct pixels for the pass. As the row gets compacted, | |
1230 | * sp will always be >= dp, so we should never overwrite anything. | |
1231 | * See the default: case for the easiest code to understand. | |
1232 | */ | |
1233 | void | |
1234 | png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass) | |
1235 | { | |
1236 | png_debug(1, "in png_do_write_interlace\n"); | |
1237 | /* we don't have to do anything on the last pass (6) */ | |
1238 | #if defined(PNG_USELESS_TESTS_SUPPORTED) | |
1239 | if (row != NULL && row_info != NULL && pass < 6) | |
1240 | #else | |
1241 | if (pass < 6) | |
1242 | #endif | |
1243 | { | |
a626cc03 | 1244 | /* each pixel depth is handled separately */ |
c801d85f KB |
1245 | switch (row_info->pixel_depth) |
1246 | { | |
1247 | case 1: | |
1248 | { | |
1249 | png_bytep sp; | |
1250 | png_bytep dp; | |
1251 | int shift; | |
1252 | int d; | |
1253 | int value; | |
1254 | png_uint_32 i; | |
a626cc03 | 1255 | png_uint_32 row_width = row_info->width; |
c801d85f KB |
1256 | |
1257 | dp = row; | |
1258 | d = 0; | |
1259 | shift = 7; | |
a626cc03 | 1260 | for (i = png_pass_start[pass]; i < row_width; |
c801d85f KB |
1261 | i += png_pass_inc[pass]) |
1262 | { | |
1263 | sp = row + (png_size_t)(i >> 3); | |
1264 | value = (int)(*sp >> (7 - (int)(i & 7))) & 0x1; | |
1265 | d |= (value << shift); | |
1266 | ||
1267 | if (shift == 0) | |
1268 | { | |
1269 | shift = 7; | |
1270 | *dp++ = (png_byte)d; | |
1271 | d = 0; | |
1272 | } | |
1273 | else | |
1274 | shift--; | |
1275 | ||
1276 | } | |
1277 | if (shift != 7) | |
1278 | *dp = (png_byte)d; | |
1279 | break; | |
1280 | } | |
1281 | case 2: | |
1282 | { | |
1283 | png_bytep sp; | |
1284 | png_bytep dp; | |
1285 | int shift; | |
1286 | int d; | |
1287 | int value; | |
1288 | png_uint_32 i; | |
a626cc03 | 1289 | png_uint_32 row_width = row_info->width; |
c801d85f KB |
1290 | |
1291 | dp = row; | |
1292 | shift = 6; | |
1293 | d = 0; | |
a626cc03 | 1294 | for (i = png_pass_start[pass]; i < row_width; |
c801d85f KB |
1295 | i += png_pass_inc[pass]) |
1296 | { | |
1297 | sp = row + (png_size_t)(i >> 2); | |
1298 | value = (*sp >> ((3 - (int)(i & 3)) << 1)) & 0x3; | |
1299 | d |= (value << shift); | |
1300 | ||
1301 | if (shift == 0) | |
1302 | { | |
1303 | shift = 6; | |
1304 | *dp++ = (png_byte)d; | |
1305 | d = 0; | |
1306 | } | |
1307 | else | |
1308 | shift -= 2; | |
1309 | } | |
1310 | if (shift != 6) | |
1311 | *dp = (png_byte)d; | |
1312 | break; | |
1313 | } | |
1314 | case 4: | |
1315 | { | |
1316 | png_bytep sp; | |
1317 | png_bytep dp; | |
1318 | int shift; | |
1319 | int d; | |
1320 | int value; | |
1321 | png_uint_32 i; | |
a626cc03 | 1322 | png_uint_32 row_width = row_info->width; |
c801d85f KB |
1323 | |
1324 | dp = row; | |
1325 | shift = 4; | |
1326 | d = 0; | |
a626cc03 | 1327 | for (i = png_pass_start[pass]; i < row_width; |
c801d85f KB |
1328 | i += png_pass_inc[pass]) |
1329 | { | |
1330 | sp = row + (png_size_t)(i >> 1); | |
1331 | value = (*sp >> ((1 - (int)(i & 1)) << 2)) & 0xf; | |
1332 | d |= (value << shift); | |
1333 | ||
1334 | if (shift == 0) | |
1335 | { | |
1336 | shift = 4; | |
1337 | *dp++ = (png_byte)d; | |
1338 | d = 0; | |
1339 | } | |
1340 | else | |
1341 | shift -= 4; | |
1342 | } | |
1343 | if (shift != 4) | |
1344 | *dp = (png_byte)d; | |
1345 | break; | |
1346 | } | |
1347 | default: | |
1348 | { | |
1349 | png_bytep sp; | |
1350 | png_bytep dp; | |
1351 | png_uint_32 i; | |
a626cc03 | 1352 | png_uint_32 row_width = row_info->width; |
c801d85f KB |
1353 | png_size_t pixel_bytes; |
1354 | ||
1355 | /* start at the beginning */ | |
1356 | dp = row; | |
1357 | /* find out how many bytes each pixel takes up */ | |
1358 | pixel_bytes = (row_info->pixel_depth >> 3); | |
1359 | /* loop through the row, only looking at the pixels that | |
1360 | matter */ | |
a626cc03 | 1361 | for (i = png_pass_start[pass]; i < row_width; |
c801d85f KB |
1362 | i += png_pass_inc[pass]) |
1363 | { | |
1364 | /* find out where the original pixel is */ | |
1365 | sp = row + (png_size_t)i * pixel_bytes; | |
1366 | /* move the pixel */ | |
1367 | if (dp != sp) | |
1368 | png_memcpy(dp, sp, pixel_bytes); | |
1369 | /* next pixel */ | |
1370 | dp += pixel_bytes; | |
1371 | } | |
1372 | break; | |
1373 | } | |
1374 | } | |
1375 | /* set new row width */ | |
1376 | row_info->width = (row_info->width + | |
1377 | png_pass_inc[pass] - 1 - | |
1378 | png_pass_start[pass]) / | |
1379 | png_pass_inc[pass]; | |
1380 | row_info->rowbytes = ((row_info->width * | |
1381 | row_info->pixel_depth + 7) >> 3); | |
1382 | } | |
1383 | } | |
1384 | #endif | |
1385 | ||
1386 | /* This filters the row, chooses which filter to use, if it has not already | |
1387 | * been specified by the application, and then writes the row out with the | |
1388 | * chosen filter. | |
1389 | */ | |
1390 | #define PNG_MAXSUM (~((png_uint_32)0) >> 1) | |
1391 | #define PNG_HISHIFT 10 | |
1392 | #define PNG_LOMASK ((png_uint_32)0xffffL) | |
1393 | #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT)) | |
1394 | void | |
1395 | png_write_find_filter(png_structp png_ptr, png_row_infop row_info) | |
1396 | { | |
1397 | png_bytep prev_row, best_row, row_buf; | |
1398 | png_uint_32 mins, bpp; | |
a626cc03 RR |
1399 | png_byte filter_to_do = png_ptr->do_filter; |
1400 | png_uint_32 row_bytes = row_info->rowbytes; | |
1401 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1402 | int num_p_filters = (int)png_ptr->num_prev_filters; | |
1403 | #endif | |
c801d85f KB |
1404 | |
1405 | png_debug(1, "in png_write_find_filter\n"); | |
1406 | /* find out how many bytes offset each pixel is */ | |
1407 | bpp = (row_info->pixel_depth + 7) / 8; | |
1408 | ||
1409 | prev_row = png_ptr->prev_row; | |
1410 | best_row = row_buf = png_ptr->row_buf; | |
1411 | mins = PNG_MAXSUM; | |
1412 | ||
1413 | /* The prediction method we use is to find which method provides the | |
1414 | * smallest value when summing the absolute values of the distances | |
a626cc03 | 1415 | * from zero, using anything >= 128 as negative numbers. This is known |
c801d85f | 1416 | * as the "minimum sum of absolute differences" heuristic. Other |
a626cc03 | 1417 | * heuristics are the "weighted minimum sum of absolute differences" |
c801d85f | 1418 | * (experimental and can in theory improve compression), and the "zlib |
a626cc03 RR |
1419 | * predictive" method (not implemented yet), which does test compressions |
1420 | * of lines using different filter methods, and then chooses the | |
1421 | * (series of) filter(s) that give minimum compressed data size (VERY | |
c801d85f | 1422 | * computationally expensive). |
a626cc03 RR |
1423 | * |
1424 | * GRR 980525: consider also | |
1425 | * (1) minimum sum of absolute differences from running average (i.e., | |
1426 | * keep running sum of non-absolute differences & count of bytes) | |
1427 | * [track dispersion, too? restart average if dispersion too large?] | |
1428 | * (1b) minimum sum of absolute differences from sliding average, probably | |
1429 | * with window size <= deflate window (usually 32K) | |
1430 | * (2) minimum sum of squared differences from zero or running average | |
1431 | * (i.e., ~ root-mean-square approach) | |
c801d85f KB |
1432 | */ |
1433 | ||
a626cc03 | 1434 | |
c801d85f KB |
1435 | /* We don't need to test the 'no filter' case if this is the only filter |
1436 | * that has been chosen, as it doesn't actually do anything to the data. | |
1437 | */ | |
a626cc03 RR |
1438 | if (filter_to_do & PNG_FILTER_NONE && |
1439 | filter_to_do != PNG_FILTER_NONE) | |
c801d85f KB |
1440 | { |
1441 | png_bytep rp; | |
1442 | png_uint_32 sum = 0; | |
1443 | png_uint_32 i; | |
1444 | int v; | |
1445 | ||
a626cc03 | 1446 | for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) |
c801d85f KB |
1447 | { |
1448 | v = *rp; | |
1449 | sum += (v < 128) ? v : 256 - v; | |
1450 | } | |
1451 | ||
1452 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1453 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1454 | { | |
1455 | png_uint_32 sumhi, sumlo; | |
a626cc03 | 1456 | int j; |
c801d85f KB |
1457 | sumlo = sum & PNG_LOMASK; |
1458 | sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */ | |
1459 | ||
1460 | /* Reduce the sum if we match any of the previous rows */ | |
a626cc03 | 1461 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1462 | { |
a626cc03 | 1463 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) |
c801d85f | 1464 | { |
a626cc03 | 1465 | sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
c801d85f | 1466 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1467 | sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
c801d85f KB |
1468 | PNG_WEIGHT_SHIFT; |
1469 | } | |
1470 | } | |
1471 | ||
1472 | /* Factor in the cost of this filter (this is here for completeness, | |
1473 | * but it makes no sense to have a "cost" for the NONE filter, as | |
1474 | * it has the minimum possible computational cost - none). | |
1475 | */ | |
1476 | sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> | |
1477 | PNG_COST_SHIFT; | |
1478 | sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> | |
1479 | PNG_COST_SHIFT; | |
1480 | ||
1481 | if (sumhi > PNG_HIMASK) | |
1482 | sum = PNG_MAXSUM; | |
1483 | else | |
1484 | sum = (sumhi << PNG_HISHIFT) + sumlo; | |
1485 | } | |
1486 | #endif | |
1487 | mins = sum; | |
1488 | } | |
1489 | ||
1490 | /* sub filter */ | |
a626cc03 RR |
1491 | if (filter_to_do == PNG_FILTER_SUB) |
1492 | /* it's the only filter so no testing is needed */ | |
1493 | { | |
1494 | png_bytep rp, lp, dp; | |
1495 | png_uint_32 i; | |
1496 | for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; | |
1497 | i++, rp++, dp++) | |
1498 | { | |
1499 | *dp = *rp; | |
1500 | } | |
1501 | for (lp = row_buf + 1; i < row_bytes; | |
1502 | i++, rp++, lp++, dp++) | |
1503 | { | |
1504 | *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); | |
1505 | } | |
1506 | best_row = png_ptr->sub_row; | |
1507 | } | |
1508 | ||
1509 | else if (filter_to_do & PNG_FILTER_SUB) | |
c801d85f KB |
1510 | { |
1511 | png_bytep rp, dp, lp; | |
1512 | png_uint_32 sum = 0, lmins = mins; | |
1513 | png_uint_32 i; | |
1514 | int v; | |
1515 | ||
1516 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
a626cc03 | 1517 | /* We temporarily increase the "minimum sum" by the factor we |
c801d85f KB |
1518 | * would reduce the sum of this filter, so that we can do the |
1519 | * early exit comparison without scaling the sum each time. | |
1520 | */ | |
1521 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1522 | { | |
a626cc03 | 1523 | int j; |
c801d85f KB |
1524 | png_uint_32 lmhi, lmlo; |
1525 | lmlo = lmins & PNG_LOMASK; | |
1526 | lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; | |
1527 | ||
a626cc03 | 1528 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1529 | { |
a626cc03 | 1530 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) |
c801d85f | 1531 | { |
a626cc03 | 1532 | lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
c801d85f | 1533 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1534 | lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
c801d85f KB |
1535 | PNG_WEIGHT_SHIFT; |
1536 | } | |
1537 | } | |
1538 | ||
1539 | lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> | |
1540 | PNG_COST_SHIFT; | |
1541 | lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> | |
1542 | PNG_COST_SHIFT; | |
1543 | ||
1544 | if (lmhi > PNG_HIMASK) | |
1545 | lmins = PNG_MAXSUM; | |
1546 | else | |
1547 | lmins = (lmhi << PNG_HISHIFT) + lmlo; | |
1548 | } | |
1549 | #endif | |
1550 | ||
1551 | for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; | |
1552 | i++, rp++, dp++) | |
1553 | { | |
1554 | v = *dp = *rp; | |
1555 | ||
1556 | sum += (v < 128) ? v : 256 - v; | |
1557 | } | |
1558 | for (lp = row_buf + 1; i < row_info->rowbytes; | |
1559 | i++, rp++, lp++, dp++) | |
1560 | { | |
1561 | v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); | |
1562 | ||
1563 | sum += (v < 128) ? v : 256 - v; | |
1564 | ||
1565 | if (sum > lmins) /* We are already worse, don't continue. */ | |
1566 | break; | |
1567 | } | |
1568 | ||
1569 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1570 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1571 | { | |
a626cc03 | 1572 | int j; |
c801d85f KB |
1573 | png_uint_32 sumhi, sumlo; |
1574 | sumlo = sum & PNG_LOMASK; | |
1575 | sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; | |
1576 | ||
a626cc03 | 1577 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1578 | { |
a626cc03 | 1579 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) |
c801d85f | 1580 | { |
a626cc03 | 1581 | sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >> |
c801d85f | 1582 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1583 | sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >> |
c801d85f KB |
1584 | PNG_WEIGHT_SHIFT; |
1585 | } | |
1586 | } | |
1587 | ||
1588 | sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> | |
1589 | PNG_COST_SHIFT; | |
1590 | sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> | |
1591 | PNG_COST_SHIFT; | |
1592 | ||
1593 | if (sumhi > PNG_HIMASK) | |
1594 | sum = PNG_MAXSUM; | |
1595 | else | |
1596 | sum = (sumhi << PNG_HISHIFT) + sumlo; | |
1597 | } | |
1598 | #endif | |
1599 | ||
1600 | if (sum < mins) | |
1601 | { | |
1602 | mins = sum; | |
1603 | best_row = png_ptr->sub_row; | |
1604 | } | |
1605 | } | |
1606 | ||
1607 | /* up filter */ | |
a626cc03 RR |
1608 | if (filter_to_do == PNG_FILTER_UP) |
1609 | { | |
1610 | png_bytep rp, dp, pp; | |
1611 | png_uint_32 i; | |
1612 | ||
1613 | for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, | |
1614 | pp = prev_row + 1; i < row_bytes; | |
1615 | i++, rp++, pp++, dp++) | |
1616 | { | |
1617 | *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); | |
1618 | } | |
1619 | best_row = png_ptr->up_row; | |
1620 | } | |
1621 | ||
1622 | else if (filter_to_do & PNG_FILTER_UP) | |
c801d85f KB |
1623 | { |
1624 | png_bytep rp, dp, pp; | |
1625 | png_uint_32 sum = 0, lmins = mins; | |
1626 | png_uint_32 i; | |
1627 | int v; | |
1628 | ||
a626cc03 | 1629 | |
c801d85f KB |
1630 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) |
1631 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1632 | { | |
a626cc03 | 1633 | int j; |
c801d85f KB |
1634 | png_uint_32 lmhi, lmlo; |
1635 | lmlo = lmins & PNG_LOMASK; | |
1636 | lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; | |
1637 | ||
a626cc03 | 1638 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1639 | { |
a626cc03 | 1640 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) |
c801d85f | 1641 | { |
a626cc03 | 1642 | lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
c801d85f | 1643 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1644 | lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
c801d85f KB |
1645 | PNG_WEIGHT_SHIFT; |
1646 | } | |
1647 | } | |
1648 | ||
1649 | lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> | |
1650 | PNG_COST_SHIFT; | |
1651 | lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> | |
1652 | PNG_COST_SHIFT; | |
1653 | ||
1654 | if (lmhi > PNG_HIMASK) | |
1655 | lmins = PNG_MAXSUM; | |
1656 | else | |
1657 | lmins = (lmhi << PNG_HISHIFT) + lmlo; | |
1658 | } | |
1659 | #endif | |
1660 | ||
1661 | for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, | |
a626cc03 | 1662 | pp = prev_row + 1; i < row_bytes; i++) |
c801d85f | 1663 | { |
a626cc03 | 1664 | v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
c801d85f KB |
1665 | |
1666 | sum += (v < 128) ? v : 256 - v; | |
1667 | ||
1668 | if (sum > lmins) /* We are already worse, don't continue. */ | |
1669 | break; | |
1670 | } | |
1671 | ||
1672 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1673 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1674 | { | |
a626cc03 | 1675 | int j; |
c801d85f KB |
1676 | png_uint_32 sumhi, sumlo; |
1677 | sumlo = sum & PNG_LOMASK; | |
1678 | sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; | |
1679 | ||
a626cc03 | 1680 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1681 | { |
a626cc03 | 1682 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) |
c801d85f | 1683 | { |
a626cc03 | 1684 | sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
c801d85f | 1685 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1686 | sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
c801d85f KB |
1687 | PNG_WEIGHT_SHIFT; |
1688 | } | |
1689 | } | |
1690 | ||
1691 | sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> | |
1692 | PNG_COST_SHIFT; | |
1693 | sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> | |
1694 | PNG_COST_SHIFT; | |
1695 | ||
1696 | if (sumhi > PNG_HIMASK) | |
1697 | sum = PNG_MAXSUM; | |
1698 | else | |
1699 | sum = (sumhi << PNG_HISHIFT) + sumlo; | |
1700 | } | |
1701 | #endif | |
1702 | ||
1703 | if (sum < mins) | |
1704 | { | |
1705 | mins = sum; | |
1706 | best_row = png_ptr->up_row; | |
1707 | } | |
1708 | } | |
1709 | ||
1710 | /* avg filter */ | |
a626cc03 RR |
1711 | if (filter_to_do == PNG_FILTER_AVG) |
1712 | { | |
1713 | png_bytep rp, dp, pp, lp; | |
1714 | png_uint_32 i; | |
1715 | for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, | |
1716 | pp = prev_row + 1; i < bpp; i++) | |
1717 | { | |
1718 | *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); | |
1719 | } | |
1720 | for (lp = row_buf + 1; i < row_bytes; i++) | |
1721 | { | |
1722 | *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) | |
1723 | & 0xff); | |
1724 | } | |
1725 | best_row = png_ptr->avg_row; | |
1726 | } | |
1727 | ||
1728 | else if (filter_to_do & PNG_FILTER_AVG) | |
c801d85f KB |
1729 | { |
1730 | png_bytep rp, dp, pp, lp; | |
1731 | png_uint_32 sum = 0, lmins = mins; | |
1732 | png_uint_32 i; | |
1733 | int v; | |
1734 | ||
1735 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1736 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1737 | { | |
a626cc03 | 1738 | int j; |
c801d85f KB |
1739 | png_uint_32 lmhi, lmlo; |
1740 | lmlo = lmins & PNG_LOMASK; | |
1741 | lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; | |
1742 | ||
a626cc03 | 1743 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1744 | { |
a626cc03 | 1745 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG) |
c801d85f | 1746 | { |
a626cc03 | 1747 | lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
c801d85f | 1748 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1749 | lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
c801d85f KB |
1750 | PNG_WEIGHT_SHIFT; |
1751 | } | |
1752 | } | |
1753 | ||
1754 | lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> | |
1755 | PNG_COST_SHIFT; | |
1756 | lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> | |
1757 | PNG_COST_SHIFT; | |
1758 | ||
1759 | if (lmhi > PNG_HIMASK) | |
1760 | lmins = PNG_MAXSUM; | |
1761 | else | |
1762 | lmins = (lmhi << PNG_HISHIFT) + lmlo; | |
1763 | } | |
1764 | #endif | |
1765 | ||
1766 | for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, | |
a626cc03 | 1767 | pp = prev_row + 1; i < bpp; i++) |
c801d85f | 1768 | { |
a626cc03 | 1769 | v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); |
c801d85f KB |
1770 | |
1771 | sum += (v < 128) ? v : 256 - v; | |
1772 | } | |
a626cc03 | 1773 | for (lp = row_buf + 1; i < row_bytes; i++) |
c801d85f | 1774 | { |
a626cc03 RR |
1775 | v = *dp++ = |
1776 | (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); | |
c801d85f KB |
1777 | |
1778 | sum += (v < 128) ? v : 256 - v; | |
1779 | ||
1780 | if (sum > lmins) /* We are already worse, don't continue. */ | |
1781 | break; | |
1782 | } | |
1783 | ||
1784 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1785 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1786 | { | |
a626cc03 | 1787 | int j; |
c801d85f KB |
1788 | png_uint_32 sumhi, sumlo; |
1789 | sumlo = sum & PNG_LOMASK; | |
1790 | sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; | |
1791 | ||
a626cc03 | 1792 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1793 | { |
a626cc03 | 1794 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) |
c801d85f | 1795 | { |
a626cc03 | 1796 | sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
c801d85f | 1797 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1798 | sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
c801d85f KB |
1799 | PNG_WEIGHT_SHIFT; |
1800 | } | |
1801 | } | |
1802 | ||
1803 | sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> | |
1804 | PNG_COST_SHIFT; | |
1805 | sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> | |
1806 | PNG_COST_SHIFT; | |
1807 | ||
1808 | if (sumhi > PNG_HIMASK) | |
1809 | sum = PNG_MAXSUM; | |
1810 | else | |
1811 | sum = (sumhi << PNG_HISHIFT) + sumlo; | |
1812 | } | |
1813 | #endif | |
1814 | ||
1815 | if (sum < mins) | |
1816 | { | |
1817 | mins = sum; | |
1818 | best_row = png_ptr->avg_row; | |
1819 | } | |
1820 | } | |
1821 | ||
1822 | /* Paeth filter */ | |
a626cc03 RR |
1823 | if (filter_to_do == PNG_FILTER_PAETH) |
1824 | { | |
1825 | png_bytep rp, dp, pp, cp, lp; | |
1826 | png_uint_32 i; | |
1827 | for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, | |
1828 | pp = prev_row + 1; i < bpp; i++) | |
1829 | { | |
1830 | *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); | |
1831 | } | |
1832 | ||
1833 | for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) | |
1834 | { | |
1835 | int a, b, c, pa, pb, pc, p; | |
1836 | ||
1837 | b = *pp++; | |
1838 | c = *cp++; | |
1839 | a = *lp++; | |
1840 | ||
1841 | p = b - c; | |
1842 | pc = a - c; | |
1843 | ||
1844 | #ifdef PNG_USE_ABS | |
1845 | pa = abs(p); | |
1846 | pb = abs(pc); | |
1847 | pc = abs(p + pc); | |
1848 | #else | |
1849 | pa = p < 0 ? -p : p; | |
1850 | pb = pc < 0 ? -pc : pc; | |
1851 | pc = (p + pc) < 0 ? -(p + pc) : p + pc; | |
1852 | #endif | |
1853 | ||
1854 | p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; | |
1855 | ||
1856 | *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); | |
1857 | } | |
1858 | best_row = png_ptr->paeth_row; | |
1859 | } | |
1860 | ||
1861 | else if (filter_to_do & PNG_FILTER_PAETH) | |
c801d85f KB |
1862 | { |
1863 | png_bytep rp, dp, pp, cp, lp; | |
1864 | png_uint_32 sum = 0, lmins = mins; | |
1865 | png_uint_32 i; | |
1866 | int v; | |
1867 | ||
1868 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1869 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1870 | { | |
a626cc03 | 1871 | int j; |
c801d85f KB |
1872 | png_uint_32 lmhi, lmlo; |
1873 | lmlo = lmins & PNG_LOMASK; | |
1874 | lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; | |
1875 | ||
a626cc03 | 1876 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1877 | { |
a626cc03 | 1878 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) |
c801d85f | 1879 | { |
a626cc03 | 1880 | lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
c801d85f | 1881 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1882 | lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
c801d85f KB |
1883 | PNG_WEIGHT_SHIFT; |
1884 | } | |
1885 | } | |
1886 | ||
1887 | lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> | |
1888 | PNG_COST_SHIFT; | |
1889 | lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> | |
1890 | PNG_COST_SHIFT; | |
1891 | ||
1892 | if (lmhi > PNG_HIMASK) | |
1893 | lmins = PNG_MAXSUM; | |
1894 | else | |
1895 | lmins = (lmhi << PNG_HISHIFT) + lmlo; | |
1896 | } | |
1897 | #endif | |
1898 | ||
1899 | for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, | |
a626cc03 | 1900 | pp = prev_row + 1; i < bpp; i++) |
c801d85f | 1901 | { |
a626cc03 | 1902 | v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
c801d85f KB |
1903 | |
1904 | sum += (v < 128) ? v : 256 - v; | |
1905 | } | |
a626cc03 RR |
1906 | |
1907 | for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) | |
c801d85f KB |
1908 | { |
1909 | int a, b, c, pa, pb, pc, p; | |
1910 | ||
a626cc03 RR |
1911 | b = *pp++; |
1912 | c = *cp++; | |
1913 | a = *lp++; | |
1914 | ||
1915 | #ifndef PNG_SLOW_PAETH | |
1916 | p = b - c; | |
1917 | pc = a - c; | |
1918 | #ifdef PNG_USE_ABS | |
1919 | pa = abs(p); | |
1920 | pb = abs(pc); | |
1921 | pc = abs(p + pc); | |
1922 | #else | |
1923 | pa = p < 0 ? -p : p; | |
1924 | pb = pc < 0 ? -pc : pc; | |
1925 | pc = (p + pc) < 0 ? -(p + pc) : p + pc; | |
1926 | #endif | |
1927 | p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; | |
1928 | #else /* PNG_SLOW_PAETH */ | |
c801d85f KB |
1929 | p = a + b - c; |
1930 | pa = abs(p - a); | |
1931 | pb = abs(p - b); | |
1932 | pc = abs(p - c); | |
c801d85f KB |
1933 | if (pa <= pb && pa <= pc) |
1934 | p = a; | |
1935 | else if (pb <= pc) | |
1936 | p = b; | |
1937 | else | |
1938 | p = c; | |
a626cc03 | 1939 | #endif /* PNG_SLOW_PAETH */ |
c801d85f | 1940 | |
a626cc03 | 1941 | v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); |
c801d85f KB |
1942 | |
1943 | sum += (v < 128) ? v : 256 - v; | |
1944 | ||
1945 | if (sum > lmins) /* We are already worse, don't continue. */ | |
1946 | break; | |
1947 | } | |
1948 | ||
1949 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1950 | if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) | |
1951 | { | |
a626cc03 | 1952 | int j; |
c801d85f KB |
1953 | png_uint_32 sumhi, sumlo; |
1954 | sumlo = sum & PNG_LOMASK; | |
1955 | sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; | |
1956 | ||
a626cc03 | 1957 | for (j = 0; j < num_p_filters; j++) |
c801d85f | 1958 | { |
a626cc03 | 1959 | if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) |
c801d85f | 1960 | { |
a626cc03 | 1961 | sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
c801d85f | 1962 | PNG_WEIGHT_SHIFT; |
a626cc03 | 1963 | sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
c801d85f KB |
1964 | PNG_WEIGHT_SHIFT; |
1965 | } | |
1966 | } | |
1967 | ||
1968 | sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> | |
1969 | PNG_COST_SHIFT; | |
1970 | sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> | |
1971 | PNG_COST_SHIFT; | |
1972 | ||
1973 | if (sumhi > PNG_HIMASK) | |
1974 | sum = PNG_MAXSUM; | |
1975 | else | |
1976 | sum = (sumhi << PNG_HISHIFT) + sumlo; | |
1977 | } | |
1978 | #endif | |
1979 | ||
1980 | if (sum < mins) | |
1981 | { | |
1982 | best_row = png_ptr->paeth_row; | |
1983 | } | |
1984 | } | |
1985 | ||
1986 | /* Do the actual writing of the filtered row data from the chosen filter. */ | |
a626cc03 | 1987 | |
c801d85f KB |
1988 | png_write_filtered_row(png_ptr, best_row); |
1989 | ||
1990 | #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) | |
1991 | /* Save the type of filter we picked this time for future calculations */ | |
1992 | if (png_ptr->num_prev_filters > 0) | |
1993 | { | |
a626cc03 RR |
1994 | int j; |
1995 | for (j = 1; j < num_p_filters; j++) | |
c801d85f | 1996 | { |
a626cc03 | 1997 | png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1]; |
c801d85f | 1998 | } |
a626cc03 | 1999 | png_ptr->prev_filters[j] = best_row[0]; |
c801d85f KB |
2000 | } |
2001 | #endif | |
2002 | } | |
2003 | ||
2004 | ||
2005 | /* Do the actual writing of a previously filtered row. */ | |
2006 | void | |
2007 | png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row) | |
2008 | { | |
2009 | png_debug(1, "in png_write_filtered_row\n"); | |
2010 | png_debug1(2, "filter = %d\n", filtered_row[0]); | |
2011 | /* set up the zlib input buffer */ | |
2012 | png_ptr->zstream.next_in = filtered_row; | |
2013 | png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1; | |
2014 | /* repeat until we have compressed all the data */ | |
2015 | do | |
2016 | { | |
2017 | int ret; /* return of zlib */ | |
2018 | ||
2019 | /* compress the data */ | |
2020 | ret = deflate(&png_ptr->zstream, Z_NO_FLUSH); | |
2021 | /* check for compression errors */ | |
2022 | if (ret != Z_OK) | |
2023 | { | |
2024 | if (png_ptr->zstream.msg != NULL) | |
2025 | png_error(png_ptr, png_ptr->zstream.msg); | |
2026 | else | |
2027 | png_error(png_ptr, "zlib error"); | |
2028 | } | |
2029 | ||
2030 | /* see if it is time to write another IDAT */ | |
2031 | if (!(png_ptr->zstream.avail_out)) | |
2032 | { | |
2033 | /* write the IDAT and reset the zlib output buffer */ | |
2034 | png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); | |
2035 | png_ptr->zstream.next_out = png_ptr->zbuf; | |
2036 | png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; | |
2037 | } | |
2038 | /* repeat until all data has been compressed */ | |
2039 | } while (png_ptr->zstream.avail_in); | |
2040 | ||
2041 | /* swap the current and previous rows */ | |
2042 | if (png_ptr->prev_row != NULL) | |
2043 | { | |
2044 | png_bytep tptr; | |
2045 | ||
2046 | tptr = png_ptr->prev_row; | |
2047 | png_ptr->prev_row = png_ptr->row_buf; | |
2048 | png_ptr->row_buf = tptr; | |
2049 | } | |
2050 | ||
2051 | /* finish row - updates counters and flushes zlib if last row */ | |
2052 | png_write_finish_row(png_ptr); | |
2053 | ||
2054 | #if defined(PNG_WRITE_FLUSH_SUPPORTED) | |
2055 | png_ptr->flush_rows++; | |
2056 | ||
2057 | if (png_ptr->flush_dist > 0 && | |
2058 | png_ptr->flush_rows >= png_ptr->flush_dist) | |
2059 | { | |
2060 | png_write_flush(png_ptr); | |
2061 | } | |
2062 | #endif /* PNG_WRITE_FLUSH_SUPPORTED */ | |
2063 | } |