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1 | |
2 /* pngread.c - read a PNG file | |
3 * | |
4 * Last changed in libpng 1.6.17 [March 26, 2015] | |
5 * Copyright (c) 1998-2015 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.) | |
8 * | |
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 | |
12 * | |
13 * This file contains routines that an application calls directly to | |
14 * read a PNG file or stream. | |
15 */ | |
16 | |
17 #include "pngpriv.h" | |
18 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) | |
19 # include <errno.h> | |
20 #endif | |
21 | |
22 #ifdef PNG_READ_SUPPORTED | |
23 | |
24 /* Create a PNG structure for reading, and allocate any memory needed. */ | |
25 PNG_FUNCTION(png_structp,PNGAPI | |
26 png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr, | |
27 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED) | |
28 { | |
29 #ifndef PNG_USER_MEM_SUPPORTED | |
30 png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr, | |
31 error_fn, warn_fn, NULL, NULL, NULL); | |
32 #else | |
33 return png_create_read_struct_2(user_png_ver, error_ptr, error_fn, | |
34 warn_fn, NULL, NULL, NULL); | |
35 } | |
36 | |
37 /* Alternate create PNG structure for reading, and allocate any memory | |
38 * needed. | |
39 */ | |
40 PNG_FUNCTION(png_structp,PNGAPI | |
41 png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr, | |
42 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, | |
43 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) | |
44 { | |
45 png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr, | |
46 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn); | |
47 #endif /* USER_MEM */ | |
48 | |
49 if (png_ptr != NULL) | |
50 { | |
51 png_ptr->mode = PNG_IS_READ_STRUCT; | |
52 | |
53 /* Added in libpng-1.6.0; this can be used to detect a read structure if | |
54 * required (it will be zero in a write structure.) | |
55 */ | |
56 # ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
57 png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE; | |
58 # endif | |
59 | |
60 # ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED | |
61 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN; | |
62 | |
63 /* In stable builds only warn if an application error can be completely | |
64 * handled. | |
65 */ | |
66 # if PNG_RELEASE_BUILD | |
67 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN; | |
68 # endif | |
69 # endif | |
70 | |
71 /* TODO: delay this, it can be done in png_init_io (if the app doesn't | |
72 * do it itself) avoiding setting the default function if it is not | |
73 * required. | |
74 */ | |
75 png_set_read_fn(png_ptr, NULL, NULL); | |
76 } | |
77 | |
78 return png_ptr; | |
79 } | |
80 | |
81 | |
82 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
83 /* Read the information before the actual image data. This has been | |
84 * changed in v0.90 to allow reading a file that already has the magic | |
85 * bytes read from the stream. You can tell libpng how many bytes have | |
86 * been read from the beginning of the stream (up to the maximum of 8) | |
87 * via png_set_sig_bytes(), and we will only check the remaining bytes | |
88 * here. The application can then have access to the signature bytes we | |
89 * read if it is determined that this isn't a valid PNG file. | |
90 */ | |
91 void PNGAPI | |
92 png_read_info(png_structrp png_ptr, png_inforp info_ptr) | |
93 { | |
94 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
95 int keep; | |
96 #endif | |
97 | |
98 png_debug(1, "in png_read_info"); | |
99 | |
100 if (png_ptr == NULL || info_ptr == NULL) | |
101 return; | |
102 | |
103 /* Read and check the PNG file signature. */ | |
104 png_read_sig(png_ptr, info_ptr); | |
105 | |
106 for (;;) | |
107 { | |
108 png_uint_32 length = png_read_chunk_header(png_ptr); | |
109 png_uint_32 chunk_name = png_ptr->chunk_name; | |
110 | |
111 /* IDAT logic needs to happen here to simplify getting the two flags | |
112 * right. | |
113 */ | |
114 if (chunk_name == png_IDAT) | |
115 { | |
116 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0) | |
117 png_chunk_error(png_ptr, "Missing IHDR before IDAT"); | |
118 | |
119 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && | |
120 (png_ptr->mode & PNG_HAVE_PLTE) == 0) | |
121 png_chunk_error(png_ptr, "Missing PLTE before IDAT"); | |
122 | |
123 else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0) | |
124 png_chunk_benign_error(png_ptr, "Too many IDATs found"); | |
125 | |
126 png_ptr->mode |= PNG_HAVE_IDAT; | |
127 } | |
128 | |
129 else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0) | |
130 png_ptr->mode |= PNG_AFTER_IDAT; | |
131 | |
132 /* This should be a binary subdivision search or a hash for | |
133 * matching the chunk name rather than a linear search. | |
134 */ | |
135 if (chunk_name == png_IHDR) | |
136 png_handle_IHDR(png_ptr, info_ptr, length); | |
137 | |
138 else if (chunk_name == png_IEND) | |
139 png_handle_IEND(png_ptr, info_ptr, length); | |
140 | |
141 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
142 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0) | |
143 { | |
144 png_handle_unknown(png_ptr, info_ptr, length, keep); | |
145 | |
146 if (chunk_name == png_PLTE) | |
147 png_ptr->mode |= PNG_HAVE_PLTE; | |
148 | |
149 else if (chunk_name == png_IDAT) | |
150 { | |
151 png_ptr->idat_size = 0; /* It has been consumed */ | |
152 break; | |
153 } | |
154 } | |
155 #endif | |
156 else if (chunk_name == png_PLTE) | |
157 png_handle_PLTE(png_ptr, info_ptr, length); | |
158 | |
159 else if (chunk_name == png_IDAT) | |
160 { | |
161 png_ptr->idat_size = length; | |
162 break; | |
163 } | |
164 | |
165 #ifdef PNG_READ_bKGD_SUPPORTED | |
166 else if (chunk_name == png_bKGD) | |
167 png_handle_bKGD(png_ptr, info_ptr, length); | |
168 #endif | |
169 | |
170 #ifdef PNG_READ_cHRM_SUPPORTED | |
171 else if (chunk_name == png_cHRM) | |
172 png_handle_cHRM(png_ptr, info_ptr, length); | |
173 #endif | |
174 | |
175 #ifdef PNG_READ_gAMA_SUPPORTED | |
176 else if (chunk_name == png_gAMA) | |
177 png_handle_gAMA(png_ptr, info_ptr, length); | |
178 #endif | |
179 | |
180 #ifdef PNG_READ_hIST_SUPPORTED | |
181 else if (chunk_name == png_hIST) | |
182 png_handle_hIST(png_ptr, info_ptr, length); | |
183 #endif | |
184 | |
185 #ifdef PNG_READ_oFFs_SUPPORTED | |
186 else if (chunk_name == png_oFFs) | |
187 png_handle_oFFs(png_ptr, info_ptr, length); | |
188 #endif | |
189 | |
190 #ifdef PNG_READ_pCAL_SUPPORTED | |
191 else if (chunk_name == png_pCAL) | |
192 png_handle_pCAL(png_ptr, info_ptr, length); | |
193 #endif | |
194 | |
195 #ifdef PNG_READ_sCAL_SUPPORTED | |
196 else if (chunk_name == png_sCAL) | |
197 png_handle_sCAL(png_ptr, info_ptr, length); | |
198 #endif | |
199 | |
200 #ifdef PNG_READ_pHYs_SUPPORTED | |
201 else if (chunk_name == png_pHYs) | |
202 png_handle_pHYs(png_ptr, info_ptr, length); | |
203 #endif | |
204 | |
205 #ifdef PNG_READ_sBIT_SUPPORTED | |
206 else if (chunk_name == png_sBIT) | |
207 png_handle_sBIT(png_ptr, info_ptr, length); | |
208 #endif | |
209 | |
210 #ifdef PNG_READ_sRGB_SUPPORTED | |
211 else if (chunk_name == png_sRGB) | |
212 png_handle_sRGB(png_ptr, info_ptr, length); | |
213 #endif | |
214 | |
215 #ifdef PNG_READ_iCCP_SUPPORTED | |
216 else if (chunk_name == png_iCCP) | |
217 png_handle_iCCP(png_ptr, info_ptr, length); | |
218 #endif | |
219 | |
220 #ifdef PNG_READ_sPLT_SUPPORTED | |
221 else if (chunk_name == png_sPLT) | |
222 png_handle_sPLT(png_ptr, info_ptr, length); | |
223 #endif | |
224 | |
225 #ifdef PNG_READ_tEXt_SUPPORTED | |
226 else if (chunk_name == png_tEXt) | |
227 png_handle_tEXt(png_ptr, info_ptr, length); | |
228 #endif | |
229 | |
230 #ifdef PNG_READ_tIME_SUPPORTED | |
231 else if (chunk_name == png_tIME) | |
232 png_handle_tIME(png_ptr, info_ptr, length); | |
233 #endif | |
234 | |
235 #ifdef PNG_READ_tRNS_SUPPORTED | |
236 else if (chunk_name == png_tRNS) | |
237 png_handle_tRNS(png_ptr, info_ptr, length); | |
238 #endif | |
239 | |
240 #ifdef PNG_READ_zTXt_SUPPORTED | |
241 else if (chunk_name == png_zTXt) | |
242 png_handle_zTXt(png_ptr, info_ptr, length); | |
243 #endif | |
244 | |
245 #ifdef PNG_READ_iTXt_SUPPORTED | |
246 else if (chunk_name == png_iTXt) | |
247 png_handle_iTXt(png_ptr, info_ptr, length); | |
248 #endif | |
249 | |
250 else | |
251 png_handle_unknown(png_ptr, info_ptr, length, | |
252 PNG_HANDLE_CHUNK_AS_DEFAULT); | |
253 } | |
254 } | |
255 #endif /* SEQUENTIAL_READ */ | |
256 | |
257 /* Optional call to update the users info_ptr structure */ | |
258 void PNGAPI | |
259 png_read_update_info(png_structrp png_ptr, png_inforp info_ptr) | |
260 { | |
261 png_debug(1, "in png_read_update_info"); | |
262 | |
263 if (png_ptr != NULL) | |
264 { | |
265 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0) | |
266 { | |
267 png_read_start_row(png_ptr); | |
268 | |
269 # ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
270 png_read_transform_info(png_ptr, info_ptr); | |
271 # else | |
272 PNG_UNUSED(info_ptr) | |
273 # endif | |
274 } | |
275 | |
276 /* New in 1.6.0 this avoids the bug of doing the initializations twice */ | |
277 else | |
278 png_app_error(png_ptr, | |
279 "png_read_update_info/png_start_read_image: duplicate call"); | |
280 } | |
281 } | |
282 | |
283 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
284 /* Initialize palette, background, etc, after transformations | |
285 * are set, but before any reading takes place. This allows | |
286 * the user to obtain a gamma-corrected palette, for example. | |
287 * If the user doesn't call this, we will do it ourselves. | |
288 */ | |
289 void PNGAPI | |
290 png_start_read_image(png_structrp png_ptr) | |
291 { | |
292 png_debug(1, "in png_start_read_image"); | |
293 | |
294 if (png_ptr != NULL) | |
295 { | |
296 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0) | |
297 png_read_start_row(png_ptr); | |
298 | |
299 /* New in 1.6.0 this avoids the bug of doing the initializations twice */ | |
300 else | |
301 png_app_error(png_ptr, | |
302 "png_start_read_image/png_read_update_info: duplicate call"); | |
303 } | |
304 } | |
305 #endif /* SEQUENTIAL_READ */ | |
306 | |
307 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
308 #ifdef PNG_MNG_FEATURES_SUPPORTED | |
309 /* Undoes intrapixel differencing, | |
310 * NOTE: this is apparently only supported in the 'sequential' reader. | |
311 */ | |
312 static void | |
313 png_do_read_intrapixel(png_row_infop row_info, png_bytep row) | |
314 { | |
315 png_debug(1, "in png_do_read_intrapixel"); | |
316 | |
317 if ( | |
318 (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0) | |
319 { | |
320 int bytes_per_pixel; | |
321 png_uint_32 row_width = row_info->width; | |
322 | |
323 if (row_info->bit_depth == 8) | |
324 { | |
325 png_bytep rp; | |
326 png_uint_32 i; | |
327 | |
328 if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
329 bytes_per_pixel = 3; | |
330 | |
331 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
332 bytes_per_pixel = 4; | |
333 | |
334 else | |
335 return; | |
336 | |
337 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) | |
338 { | |
339 *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff); | |
340 *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff); | |
341 } | |
342 } | |
343 else if (row_info->bit_depth == 16) | |
344 { | |
345 png_bytep rp; | |
346 png_uint_32 i; | |
347 | |
348 if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
349 bytes_per_pixel = 6; | |
350 | |
351 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
352 bytes_per_pixel = 8; | |
353 | |
354 else | |
355 return; | |
356 | |
357 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) | |
358 { | |
359 png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); | |
360 png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); | |
361 png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); | |
362 png_uint_32 red = (s0 + s1 + 65536) & 0xffff; | |
363 png_uint_32 blue = (s2 + s1 + 65536) & 0xffff; | |
364 *(rp ) = (png_byte)((red >> 8) & 0xff); | |
365 *(rp + 1) = (png_byte)(red & 0xff); | |
366 *(rp + 4) = (png_byte)((blue >> 8) & 0xff); | |
367 *(rp + 5) = (png_byte)(blue & 0xff); | |
368 } | |
369 } | |
370 } | |
371 } | |
372 #endif /* MNG_FEATURES */ | |
373 | |
374 void PNGAPI | |
375 png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row) | |
376 { | |
377 png_row_info row_info; | |
378 | |
379 if (png_ptr == NULL) | |
380 return; | |
381 | |
382 png_debug2(1, "in png_read_row (row %lu, pass %d)", | |
383 (unsigned long)png_ptr->row_number, png_ptr->pass); | |
384 | |
385 /* png_read_start_row sets the information (in particular iwidth) for this | |
386 * interlace pass. | |
387 */ | |
388 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0) | |
389 png_read_start_row(png_ptr); | |
390 | |
391 /* 1.5.6: row_info moved out of png_struct to a local here. */ | |
392 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */ | |
393 row_info.color_type = png_ptr->color_type; | |
394 row_info.bit_depth = png_ptr->bit_depth; | |
395 row_info.channels = png_ptr->channels; | |
396 row_info.pixel_depth = png_ptr->pixel_depth; | |
397 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); | |
398 | |
399 #ifdef PNG_WARNINGS_SUPPORTED | |
400 if (png_ptr->row_number == 0 && png_ptr->pass == 0) | |
401 { | |
402 /* Check for transforms that have been set but were defined out */ | |
403 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED) | |
404 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0) | |
405 png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined"); | |
406 #endif | |
407 | |
408 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED) | |
409 if ((png_ptr->transformations & PNG_FILLER) != 0) | |
410 png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined"); | |
411 #endif | |
412 | |
413 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \ | |
414 !defined(PNG_READ_PACKSWAP_SUPPORTED) | |
415 if ((png_ptr->transformations & PNG_PACKSWAP) != 0) | |
416 png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined"); | |
417 #endif | |
418 | |
419 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED) | |
420 if ((png_ptr->transformations & PNG_PACK) != 0) | |
421 png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined"); | |
422 #endif | |
423 | |
424 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) | |
425 if ((png_ptr->transformations & PNG_SHIFT) != 0) | |
426 png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined"); | |
427 #endif | |
428 | |
429 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED) | |
430 if ((png_ptr->transformations & PNG_BGR) != 0) | |
431 png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined"); | |
432 #endif | |
433 | |
434 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED) | |
435 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0) | |
436 png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined"); | |
437 #endif | |
438 } | |
439 #endif /* WARNINGS */ | |
440 | |
441 #ifdef PNG_READ_INTERLACING_SUPPORTED | |
442 /* If interlaced and we do not need a new row, combine row and return. | |
443 * Notice that the pixels we have from previous rows have been transformed | |
444 * already; we can only combine like with like (transformed or | |
445 * untransformed) and, because of the libpng API for interlaced images, this | |
446 * means we must transform before de-interlacing. | |
447 */ | |
448 if (png_ptr->interlaced != 0 && | |
449 (png_ptr->transformations & PNG_INTERLACE) != 0) | |
450 { | |
451 switch (png_ptr->pass) | |
452 { | |
453 case 0: | |
454 if (png_ptr->row_number & 0x07) | |
455 { | |
456 if (dsp_row != NULL) | |
457 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
458 png_read_finish_row(png_ptr); | |
459 return; | |
460 } | |
461 break; | |
462 | |
463 case 1: | |
464 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5) | |
465 { | |
466 if (dsp_row != NULL) | |
467 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
468 | |
469 png_read_finish_row(png_ptr); | |
470 return; | |
471 } | |
472 break; | |
473 | |
474 case 2: | |
475 if ((png_ptr->row_number & 0x07) != 4) | |
476 { | |
477 if (dsp_row != NULL && (png_ptr->row_number & 4)) | |
478 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
479 | |
480 png_read_finish_row(png_ptr); | |
481 return; | |
482 } | |
483 break; | |
484 | |
485 case 3: | |
486 if ((png_ptr->row_number & 3) || png_ptr->width < 3) | |
487 { | |
488 if (dsp_row != NULL) | |
489 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
490 | |
491 png_read_finish_row(png_ptr); | |
492 return; | |
493 } | |
494 break; | |
495 | |
496 case 4: | |
497 if ((png_ptr->row_number & 3) != 2) | |
498 { | |
499 if (dsp_row != NULL && (png_ptr->row_number & 2)) | |
500 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
501 | |
502 png_read_finish_row(png_ptr); | |
503 return; | |
504 } | |
505 break; | |
506 | |
507 case 5: | |
508 if ((png_ptr->row_number & 1) || png_ptr->width < 2) | |
509 { | |
510 if (dsp_row != NULL) | |
511 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
512 | |
513 png_read_finish_row(png_ptr); | |
514 return; | |
515 } | |
516 break; | |
517 | |
518 default: | |
519 case 6: | |
520 if ((png_ptr->row_number & 1) == 0) | |
521 { | |
522 png_read_finish_row(png_ptr); | |
523 return; | |
524 } | |
525 break; | |
526 } | |
527 } | |
528 #endif | |
529 | |
530 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0) | |
531 png_error(png_ptr, "Invalid attempt to read row data"); | |
532 | |
533 /* Fill the row with IDAT data: */ | |
534 png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1); | |
535 | |
536 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE) | |
537 { | |
538 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST) | |
539 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1, | |
540 png_ptr->prev_row + 1, png_ptr->row_buf[0]); | |
541 else | |
542 png_error(png_ptr, "bad adaptive filter value"); | |
543 } | |
544 | |
545 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before | |
546 * 1.5.6, while the buffer really is this big in current versions of libpng | |
547 * it may not be in the future, so this was changed just to copy the | |
548 * interlaced count: | |
549 */ | |
550 memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1); | |
551 | |
552 #ifdef PNG_MNG_FEATURES_SUPPORTED | |
553 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 && | |
554 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING)) | |
555 { | |
556 /* Intrapixel differencing */ | |
557 png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1); | |
558 } | |
559 #endif | |
560 | |
561 #ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
562 if (png_ptr->transformations) | |
563 png_do_read_transformations(png_ptr, &row_info); | |
564 #endif | |
565 | |
566 /* The transformed pixel depth should match the depth now in row_info. */ | |
567 if (png_ptr->transformed_pixel_depth == 0) | |
568 { | |
569 png_ptr->transformed_pixel_depth = row_info.pixel_depth; | |
570 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth) | |
571 png_error(png_ptr, "sequential row overflow"); | |
572 } | |
573 | |
574 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth) | |
575 png_error(png_ptr, "internal sequential row size calculation error"); | |
576 | |
577 #ifdef PNG_READ_INTERLACING_SUPPORTED | |
578 /* Expand interlaced rows to full size */ | |
579 if (png_ptr->interlaced != 0 && | |
580 (png_ptr->transformations & PNG_INTERLACE) != 0) | |
581 { | |
582 if (png_ptr->pass < 6) | |
583 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass, | |
584 png_ptr->transformations); | |
585 | |
586 if (dsp_row != NULL) | |
587 png_combine_row(png_ptr, dsp_row, 1/*display*/); | |
588 | |
589 if (row != NULL) | |
590 png_combine_row(png_ptr, row, 0/*row*/); | |
591 } | |
592 | |
593 else | |
594 #endif | |
595 { | |
596 if (row != NULL) | |
597 png_combine_row(png_ptr, row, -1/*ignored*/); | |
598 | |
599 if (dsp_row != NULL) | |
600 png_combine_row(png_ptr, dsp_row, -1/*ignored*/); | |
601 } | |
602 png_read_finish_row(png_ptr); | |
603 | |
604 if (png_ptr->read_row_fn != NULL) | |
605 (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass); | |
606 | |
607 } | |
608 #endif /* SEQUENTIAL_READ */ | |
609 | |
610 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
611 /* Read one or more rows of image data. If the image is interlaced, | |
612 * and png_set_interlace_handling() has been called, the rows need to | |
613 * contain the contents of the rows from the previous pass. If the | |
614 * image has alpha or transparency, and png_handle_alpha()[*] has been | |
615 * called, the rows contents must be initialized to the contents of the | |
616 * screen. | |
617 * | |
618 * "row" holds the actual image, and pixels are placed in it | |
619 * as they arrive. If the image is displayed after each pass, it will | |
620 * appear to "sparkle" in. "display_row" can be used to display a | |
621 * "chunky" progressive image, with finer detail added as it becomes | |
622 * available. If you do not want this "chunky" display, you may pass | |
623 * NULL for display_row. If you do not want the sparkle display, and | |
624 * you have not called png_handle_alpha(), you may pass NULL for rows. | |
625 * If you have called png_handle_alpha(), and the image has either an | |
626 * alpha channel or a transparency chunk, you must provide a buffer for | |
627 * rows. In this case, you do not have to provide a display_row buffer | |
628 * also, but you may. If the image is not interlaced, or if you have | |
629 * not called png_set_interlace_handling(), the display_row buffer will | |
630 * be ignored, so pass NULL to it. | |
631 * | |
632 * [*] png_handle_alpha() does not exist yet, as of this version of libpng | |
633 */ | |
634 | |
635 void PNGAPI | |
636 png_read_rows(png_structrp png_ptr, png_bytepp row, | |
637 png_bytepp display_row, png_uint_32 num_rows) | |
638 { | |
639 png_uint_32 i; | |
640 png_bytepp rp; | |
641 png_bytepp dp; | |
642 | |
643 png_debug(1, "in png_read_rows"); | |
644 | |
645 if (png_ptr == NULL) | |
646 return; | |
647 | |
648 rp = row; | |
649 dp = display_row; | |
650 if (rp != NULL && dp != NULL) | |
651 for (i = 0; i < num_rows; i++) | |
652 { | |
653 png_bytep rptr = *rp++; | |
654 png_bytep dptr = *dp++; | |
655 | |
656 png_read_row(png_ptr, rptr, dptr); | |
657 } | |
658 | |
659 else if (rp != NULL) | |
660 for (i = 0; i < num_rows; i++) | |
661 { | |
662 png_bytep rptr = *rp; | |
663 png_read_row(png_ptr, rptr, NULL); | |
664 rp++; | |
665 } | |
666 | |
667 else if (dp != NULL) | |
668 for (i = 0; i < num_rows; i++) | |
669 { | |
670 png_bytep dptr = *dp; | |
671 png_read_row(png_ptr, NULL, dptr); | |
672 dp++; | |
673 } | |
674 } | |
675 #endif /* SEQUENTIAL_READ */ | |
676 | |
677 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
678 /* Read the entire image. If the image has an alpha channel or a tRNS | |
679 * chunk, and you have called png_handle_alpha()[*], you will need to | |
680 * initialize the image to the current image that PNG will be overlaying. | |
681 * We set the num_rows again here, in case it was incorrectly set in | |
682 * png_read_start_row() by a call to png_read_update_info() or | |
683 * png_start_read_image() if png_set_interlace_handling() wasn't called | |
684 * prior to either of these functions like it should have been. You can | |
685 * only call this function once. If you desire to have an image for | |
686 * each pass of a interlaced image, use png_read_rows() instead. | |
687 * | |
688 * [*] png_handle_alpha() does not exist yet, as of this version of libpng | |
689 */ | |
690 void PNGAPI | |
691 png_read_image(png_structrp png_ptr, png_bytepp image) | |
692 { | |
693 png_uint_32 i, image_height; | |
694 int pass, j; | |
695 png_bytepp rp; | |
696 | |
697 png_debug(1, "in png_read_image"); | |
698 | |
699 if (png_ptr == NULL) | |
700 return; | |
701 | |
702 #ifdef PNG_READ_INTERLACING_SUPPORTED | |
703 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0) | |
704 { | |
705 pass = png_set_interlace_handling(png_ptr); | |
706 /* And make sure transforms are initialized. */ | |
707 png_start_read_image(png_ptr); | |
708 } | |
709 else | |
710 { | |
711 if (png_ptr->interlaced != 0 && | |
712 (png_ptr->transformations & PNG_INTERLACE) == 0) | |
713 { | |
714 /* Caller called png_start_read_image or png_read_update_info without | |
715 * first turning on the PNG_INTERLACE transform. We can fix this here, | |
716 * but the caller should do it! | |
717 */ | |
718 png_warning(png_ptr, "Interlace handling should be turned on when " | |
719 "using png_read_image"); | |
720 /* Make sure this is set correctly */ | |
721 png_ptr->num_rows = png_ptr->height; | |
722 } | |
723 | |
724 /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in | |
725 * the above error case. | |
726 */ | |
727 pass = png_set_interlace_handling(png_ptr); | |
728 } | |
729 #else | |
730 if (png_ptr->interlaced) | |
731 png_error(png_ptr, | |
732 "Cannot read interlaced image -- interlace handler disabled"); | |
733 | |
734 pass = 1; | |
735 #endif | |
736 | |
737 image_height=png_ptr->height; | |
738 | |
739 for (j = 0; j < pass; j++) | |
740 { | |
741 rp = image; | |
742 for (i = 0; i < image_height; i++) | |
743 { | |
744 png_read_row(png_ptr, *rp, NULL); | |
745 rp++; | |
746 } | |
747 } | |
748 } | |
749 #endif /* SEQUENTIAL_READ */ | |
750 | |
751 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
752 /* Read the end of the PNG file. Will not read past the end of the | |
753 * file, will verify the end is accurate, and will read any comments | |
754 * or time information at the end of the file, if info is not NULL. | |
755 */ | |
756 void PNGAPI | |
757 png_read_end(png_structrp png_ptr, png_inforp info_ptr) | |
758 { | |
759 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
760 int keep; | |
761 #endif | |
762 | |
763 png_debug(1, "in png_read_end"); | |
764 | |
765 if (png_ptr == NULL) | |
766 return; | |
767 | |
768 /* If png_read_end is called in the middle of reading the rows there may | |
769 * still be pending IDAT data and an owned zstream. Deal with this here. | |
770 */ | |
771 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
772 if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0) | |
773 #endif | |
774 png_read_finish_IDAT(png_ptr); | |
775 | |
776 #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED | |
777 /* Report invalid palette index; added at libng-1.5.10 */ | |
778 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && | |
779 png_ptr->num_palette_max > png_ptr->num_palette) | |
780 png_benign_error(png_ptr, "Read palette index exceeding num_palette"); | |
781 #endif | |
782 | |
783 do | |
784 { | |
785 png_uint_32 length = png_read_chunk_header(png_ptr); | |
786 png_uint_32 chunk_name = png_ptr->chunk_name; | |
787 | |
788 if (chunk_name == png_IEND) | |
789 png_handle_IEND(png_ptr, info_ptr, length); | |
790 | |
791 else if (chunk_name == png_IHDR) | |
792 png_handle_IHDR(png_ptr, info_ptr, length); | |
793 | |
794 else if (info_ptr == NULL) | |
795 png_crc_finish(png_ptr, length); | |
796 | |
797 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
798 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0) | |
799 { | |
800 if (chunk_name == png_IDAT) | |
801 { | |
802 if ((length > 0) || | |
803 (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0) | |
804 png_benign_error(png_ptr, "Too many IDATs found"); | |
805 } | |
806 png_handle_unknown(png_ptr, info_ptr, length, keep); | |
807 if (chunk_name == png_PLTE) | |
808 png_ptr->mode |= PNG_HAVE_PLTE; | |
809 } | |
810 #endif | |
811 | |
812 else if (chunk_name == png_IDAT) | |
813 { | |
814 /* Zero length IDATs are legal after the last IDAT has been | |
815 * read, but not after other chunks have been read. | |
816 */ | |
817 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0) | |
818 png_benign_error(png_ptr, "Too many IDATs found"); | |
819 | |
820 png_crc_finish(png_ptr, length); | |
821 } | |
822 else if (chunk_name == png_PLTE) | |
823 png_handle_PLTE(png_ptr, info_ptr, length); | |
824 | |
825 #ifdef PNG_READ_bKGD_SUPPORTED | |
826 else if (chunk_name == png_bKGD) | |
827 png_handle_bKGD(png_ptr, info_ptr, length); | |
828 #endif | |
829 | |
830 #ifdef PNG_READ_cHRM_SUPPORTED | |
831 else if (chunk_name == png_cHRM) | |
832 png_handle_cHRM(png_ptr, info_ptr, length); | |
833 #endif | |
834 | |
835 #ifdef PNG_READ_gAMA_SUPPORTED | |
836 else if (chunk_name == png_gAMA) | |
837 png_handle_gAMA(png_ptr, info_ptr, length); | |
838 #endif | |
839 | |
840 #ifdef PNG_READ_hIST_SUPPORTED | |
841 else if (chunk_name == png_hIST) | |
842 png_handle_hIST(png_ptr, info_ptr, length); | |
843 #endif | |
844 | |
845 #ifdef PNG_READ_oFFs_SUPPORTED | |
846 else if (chunk_name == png_oFFs) | |
847 png_handle_oFFs(png_ptr, info_ptr, length); | |
848 #endif | |
849 | |
850 #ifdef PNG_READ_pCAL_SUPPORTED | |
851 else if (chunk_name == png_pCAL) | |
852 png_handle_pCAL(png_ptr, info_ptr, length); | |
853 #endif | |
854 | |
855 #ifdef PNG_READ_sCAL_SUPPORTED | |
856 else if (chunk_name == png_sCAL) | |
857 png_handle_sCAL(png_ptr, info_ptr, length); | |
858 #endif | |
859 | |
860 #ifdef PNG_READ_pHYs_SUPPORTED | |
861 else if (chunk_name == png_pHYs) | |
862 png_handle_pHYs(png_ptr, info_ptr, length); | |
863 #endif | |
864 | |
865 #ifdef PNG_READ_sBIT_SUPPORTED | |
866 else if (chunk_name == png_sBIT) | |
867 png_handle_sBIT(png_ptr, info_ptr, length); | |
868 #endif | |
869 | |
870 #ifdef PNG_READ_sRGB_SUPPORTED | |
871 else if (chunk_name == png_sRGB) | |
872 png_handle_sRGB(png_ptr, info_ptr, length); | |
873 #endif | |
874 | |
875 #ifdef PNG_READ_iCCP_SUPPORTED | |
876 else if (chunk_name == png_iCCP) | |
877 png_handle_iCCP(png_ptr, info_ptr, length); | |
878 #endif | |
879 | |
880 #ifdef PNG_READ_sPLT_SUPPORTED | |
881 else if (chunk_name == png_sPLT) | |
882 png_handle_sPLT(png_ptr, info_ptr, length); | |
883 #endif | |
884 | |
885 #ifdef PNG_READ_tEXt_SUPPORTED | |
886 else if (chunk_name == png_tEXt) | |
887 png_handle_tEXt(png_ptr, info_ptr, length); | |
888 #endif | |
889 | |
890 #ifdef PNG_READ_tIME_SUPPORTED | |
891 else if (chunk_name == png_tIME) | |
892 png_handle_tIME(png_ptr, info_ptr, length); | |
893 #endif | |
894 | |
895 #ifdef PNG_READ_tRNS_SUPPORTED | |
896 else if (chunk_name == png_tRNS) | |
897 png_handle_tRNS(png_ptr, info_ptr, length); | |
898 #endif | |
899 | |
900 #ifdef PNG_READ_zTXt_SUPPORTED | |
901 else if (chunk_name == png_zTXt) | |
902 png_handle_zTXt(png_ptr, info_ptr, length); | |
903 #endif | |
904 | |
905 #ifdef PNG_READ_iTXt_SUPPORTED | |
906 else if (chunk_name == png_iTXt) | |
907 png_handle_iTXt(png_ptr, info_ptr, length); | |
908 #endif | |
909 | |
910 else | |
911 png_handle_unknown(png_ptr, info_ptr, length, | |
912 PNG_HANDLE_CHUNK_AS_DEFAULT); | |
913 } while ((png_ptr->mode & PNG_HAVE_IEND) == 0); | |
914 } | |
915 #endif /* SEQUENTIAL_READ */ | |
916 | |
917 /* Free all memory used in the read struct */ | |
918 static void | |
919 png_read_destroy(png_structrp png_ptr) | |
920 { | |
921 png_debug(1, "in png_read_destroy"); | |
922 | |
923 #ifdef PNG_READ_GAMMA_SUPPORTED | |
924 png_destroy_gamma_table(png_ptr); | |
925 #endif | |
926 | |
927 png_free(png_ptr, png_ptr->big_row_buf); | |
928 png_ptr->big_row_buf = NULL; | |
929 png_free(png_ptr, png_ptr->big_prev_row); | |
930 png_ptr->big_prev_row = NULL; | |
931 png_free(png_ptr, png_ptr->read_buffer); | |
932 png_ptr->read_buffer = NULL; | |
933 | |
934 #ifdef PNG_READ_QUANTIZE_SUPPORTED | |
935 png_free(png_ptr, png_ptr->palette_lookup); | |
936 png_ptr->palette_lookup = NULL; | |
937 png_free(png_ptr, png_ptr->quantize_index); | |
938 png_ptr->quantize_index = NULL; | |
939 #endif | |
940 | |
941 if ((png_ptr->free_me & PNG_FREE_PLTE) != 0) | |
942 { | |
943 png_zfree(png_ptr, png_ptr->palette); | |
944 png_ptr->palette = NULL; | |
945 } | |
946 png_ptr->free_me &= ~PNG_FREE_PLTE; | |
947 | |
948 #if defined(PNG_tRNS_SUPPORTED) || \ | |
949 defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) | |
950 if ((png_ptr->free_me & PNG_FREE_TRNS) != 0) | |
951 { | |
952 png_free(png_ptr, png_ptr->trans_alpha); | |
953 png_ptr->trans_alpha = NULL; | |
954 } | |
955 png_ptr->free_me &= ~PNG_FREE_TRNS; | |
956 #endif | |
957 | |
958 inflateEnd(&png_ptr->zstream); | |
959 | |
960 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED | |
961 png_free(png_ptr, png_ptr->save_buffer); | |
962 png_ptr->save_buffer = NULL; | |
963 #endif | |
964 | |
965 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \ | |
966 defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) | |
967 png_free(png_ptr, png_ptr->unknown_chunk.data); | |
968 png_ptr->unknown_chunk.data = NULL; | |
969 #endif | |
970 | |
971 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED | |
972 png_free(png_ptr, png_ptr->chunk_list); | |
973 png_ptr->chunk_list = NULL; | |
974 #endif | |
975 | |
976 /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error | |
977 * callbacks are still set at this point. They are required to complete the | |
978 * destruction of the png_struct itself. | |
979 */ | |
980 } | |
981 | |
982 /* Free all memory used by the read */ | |
983 void PNGAPI | |
984 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr, | |
985 png_infopp end_info_ptr_ptr) | |
986 { | |
987 png_structrp png_ptr = NULL; | |
988 | |
989 png_debug(1, "in png_destroy_read_struct"); | |
990 | |
991 if (png_ptr_ptr != NULL) | |
992 png_ptr = *png_ptr_ptr; | |
993 | |
994 if (png_ptr == NULL) | |
995 return; | |
996 | |
997 /* libpng 1.6.0: use the API to destroy info structs to ensure consistent | |
998 * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API. | |
999 * The extra was, apparently, unnecessary yet this hides memory leak bugs. | |
1000 */ | |
1001 png_destroy_info_struct(png_ptr, end_info_ptr_ptr); | |
1002 png_destroy_info_struct(png_ptr, info_ptr_ptr); | |
1003 | |
1004 *png_ptr_ptr = NULL; | |
1005 png_read_destroy(png_ptr); | |
1006 png_destroy_png_struct(png_ptr); | |
1007 } | |
1008 | |
1009 void PNGAPI | |
1010 png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn) | |
1011 { | |
1012 if (png_ptr == NULL) | |
1013 return; | |
1014 | |
1015 png_ptr->read_row_fn = read_row_fn; | |
1016 } | |
1017 | |
1018 | |
1019 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED | |
1020 #ifdef PNG_INFO_IMAGE_SUPPORTED | |
1021 void PNGAPI | |
1022 png_read_png(png_structrp png_ptr, png_inforp info_ptr, | |
1023 int transforms, | |
1024 voidp params) | |
1025 { | |
1026 if (png_ptr == NULL || info_ptr == NULL) | |
1027 return; | |
1028 | |
1029 /* png_read_info() gives us all of the information from the | |
1030 * PNG file before the first IDAT (image data chunk). | |
1031 */ | |
1032 png_read_info(png_ptr, info_ptr); | |
1033 if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep))) | |
1034 png_error(png_ptr, "Image is too high to process with png_read_png()"); | |
1035 | |
1036 /* -------------- image transformations start here ------------------- */ | |
1037 /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM | |
1038 * is not implemented. This will only happen in de-configured (non-default) | |
1039 * libpng builds. The results can be unexpected - png_read_png may return | |
1040 * short or mal-formed rows because the transform is skipped. | |
1041 */ | |
1042 | |
1043 /* Tell libpng to strip 16-bit/color files down to 8 bits per color. | |
1044 */ | |
1045 if ((transforms & PNG_TRANSFORM_SCALE_16) != 0) | |
1046 /* Added at libpng-1.5.4. "strip_16" produces the same result that it | |
1047 * did in earlier versions, while "scale_16" is now more accurate. | |
1048 */ | |
1049 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED | |
1050 png_set_scale_16(png_ptr); | |
1051 #else | |
1052 png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported"); | |
1053 #endif | |
1054 | |
1055 /* If both SCALE and STRIP are required pngrtran will effectively cancel the | |
1056 * latter by doing SCALE first. This is ok and allows apps not to check for | |
1057 * which is supported to get the right answer. | |
1058 */ | |
1059 if ((transforms & PNG_TRANSFORM_STRIP_16) != 0) | |
1060 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED | |
1061 png_set_strip_16(png_ptr); | |
1062 #else | |
1063 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported"); | |
1064 #endif | |
1065 | |
1066 /* Strip alpha bytes from the input data without combining with | |
1067 * the background (not recommended). | |
1068 */ | |
1069 if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0) | |
1070 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED | |
1071 png_set_strip_alpha(png_ptr); | |
1072 #else | |
1073 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported"); | |
1074 #endif | |
1075 | |
1076 /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single | |
1077 * byte into separate bytes (useful for paletted and grayscale images). | |
1078 */ | |
1079 if ((transforms & PNG_TRANSFORM_PACKING) != 0) | |
1080 #ifdef PNG_READ_PACK_SUPPORTED | |
1081 png_set_packing(png_ptr); | |
1082 #else | |
1083 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported"); | |
1084 #endif | |
1085 | |
1086 /* Change the order of packed pixels to least significant bit first | |
1087 * (not useful if you are using png_set_packing). | |
1088 */ | |
1089 if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0) | |
1090 #ifdef PNG_READ_PACKSWAP_SUPPORTED | |
1091 png_set_packswap(png_ptr); | |
1092 #else | |
1093 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported"); | |
1094 #endif | |
1095 | |
1096 /* Expand paletted colors into true RGB triplets | |
1097 * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel | |
1098 * Expand paletted or RGB images with transparency to full alpha | |
1099 * channels so the data will be available as RGBA quartets. | |
1100 */ | |
1101 if ((transforms & PNG_TRANSFORM_EXPAND) != 0) | |
1102 #ifdef PNG_READ_EXPAND_SUPPORTED | |
1103 png_set_expand(png_ptr); | |
1104 #else | |
1105 png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported"); | |
1106 #endif | |
1107 | |
1108 /* We don't handle background color or gamma transformation or quantizing. | |
1109 */ | |
1110 | |
1111 /* Invert monochrome files to have 0 as white and 1 as black | |
1112 */ | |
1113 if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0) | |
1114 #ifdef PNG_READ_INVERT_SUPPORTED | |
1115 png_set_invert_mono(png_ptr); | |
1116 #else | |
1117 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported"); | |
1118 #endif | |
1119 | |
1120 /* If you want to shift the pixel values from the range [0,255] or | |
1121 * [0,65535] to the original [0,7] or [0,31], or whatever range the | |
1122 * colors were originally in: | |
1123 */ | |
1124 if ((transforms & PNG_TRANSFORM_SHIFT) != 0) | |
1125 #ifdef PNG_READ_SHIFT_SUPPORTED | |
1126 if ((info_ptr->valid & PNG_INFO_sBIT) != 0) | |
1127 png_set_shift(png_ptr, &info_ptr->sig_bit); | |
1128 #else | |
1129 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported"); | |
1130 #endif | |
1131 | |
1132 /* Flip the RGB pixels to BGR (or RGBA to BGRA) */ | |
1133 if ((transforms & PNG_TRANSFORM_BGR) != 0) | |
1134 #ifdef PNG_READ_BGR_SUPPORTED | |
1135 png_set_bgr(png_ptr); | |
1136 #else | |
1137 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported"); | |
1138 #endif | |
1139 | |
1140 /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */ | |
1141 if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0) | |
1142 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED | |
1143 png_set_swap_alpha(png_ptr); | |
1144 #else | |
1145 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported"); | |
1146 #endif | |
1147 | |
1148 /* Swap bytes of 16-bit files to least significant byte first */ | |
1149 if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0) | |
1150 #ifdef PNG_READ_SWAP_SUPPORTED | |
1151 png_set_swap(png_ptr); | |
1152 #else | |
1153 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported"); | |
1154 #endif | |
1155 | |
1156 /* Added at libpng-1.2.41 */ | |
1157 /* Invert the alpha channel from opacity to transparency */ | |
1158 if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0) | |
1159 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED | |
1160 png_set_invert_alpha(png_ptr); | |
1161 #else | |
1162 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported"); | |
1163 #endif | |
1164 | |
1165 /* Added at libpng-1.2.41 */ | |
1166 /* Expand grayscale image to RGB */ | |
1167 if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0) | |
1168 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED | |
1169 png_set_gray_to_rgb(png_ptr); | |
1170 #else | |
1171 png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported"); | |
1172 #endif | |
1173 | |
1174 /* Added at libpng-1.5.4 */ | |
1175 if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0) | |
1176 #ifdef PNG_READ_EXPAND_16_SUPPORTED | |
1177 png_set_expand_16(png_ptr); | |
1178 #else | |
1179 png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported"); | |
1180 #endif | |
1181 | |
1182 /* We don't handle adding filler bytes */ | |
1183 | |
1184 /* We use png_read_image and rely on that for interlace handling, but we also | |
1185 * call png_read_update_info therefore must turn on interlace handling now: | |
1186 */ | |
1187 (void)png_set_interlace_handling(png_ptr); | |
1188 | |
1189 /* Optional call to gamma correct and add the background to the palette | |
1190 * and update info structure. REQUIRED if you are expecting libpng to | |
1191 * update the palette for you (i.e., you selected such a transform above). | |
1192 */ | |
1193 png_read_update_info(png_ptr, info_ptr); | |
1194 | |
1195 /* -------------- image transformations end here ------------------- */ | |
1196 | |
1197 png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0); | |
1198 if (info_ptr->row_pointers == NULL) | |
1199 { | |
1200 png_uint_32 iptr; | |
1201 | |
1202 info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr, | |
1203 info_ptr->height * (sizeof (png_bytep)))); | |
1204 | |
1205 for (iptr=0; iptr<info_ptr->height; iptr++) | |
1206 info_ptr->row_pointers[iptr] = NULL; | |
1207 | |
1208 info_ptr->free_me |= PNG_FREE_ROWS; | |
1209 | |
1210 for (iptr = 0; iptr < info_ptr->height; iptr++) | |
1211 info_ptr->row_pointers[iptr] = png_voidcast(png_bytep, | |
1212 png_malloc(png_ptr, info_ptr->rowbytes)); | |
1213 } | |
1214 | |
1215 png_read_image(png_ptr, info_ptr->row_pointers); | |
1216 info_ptr->valid |= PNG_INFO_IDAT; | |
1217 | |
1218 /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */ | |
1219 png_read_end(png_ptr, info_ptr); | |
1220 | |
1221 PNG_UNUSED(params) | |
1222 } | |
1223 #endif /* INFO_IMAGE */ | |
1224 #endif /* SEQUENTIAL_READ */ | |
1225 | |
1226 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED | |
1227 /* SIMPLIFIED READ | |
1228 * | |
1229 * This code currently relies on the sequential reader, though it could easily | |
1230 * be made to work with the progressive one. | |
1231 */ | |
1232 /* Arguments to png_image_finish_read: */ | |
1233 | |
1234 /* Encoding of PNG data (used by the color-map code) */ | |
1235 # define P_NOTSET 0 /* File encoding not yet known */ | |
1236 # define P_sRGB 1 /* 8-bit encoded to sRGB gamma */ | |
1237 # define P_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */ | |
1238 # define P_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */ | |
1239 # define P_LINEAR8 4 /* 8-bit linear: only from a file value */ | |
1240 | |
1241 /* Color-map processing: after libpng has run on the PNG image further | |
1242 * processing may be needed to convert the data to color-map indices. | |
1243 */ | |
1244 #define PNG_CMAP_NONE 0 | |
1245 #define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */ | |
1246 #define PNG_CMAP_TRANS 2 /* Process GA data to a background index */ | |
1247 #define PNG_CMAP_RGB 3 /* Process RGB data */ | |
1248 #define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */ | |
1249 | |
1250 /* The following document where the background is for each processing case. */ | |
1251 #define PNG_CMAP_NONE_BACKGROUND 256 | |
1252 #define PNG_CMAP_GA_BACKGROUND 231 | |
1253 #define PNG_CMAP_TRANS_BACKGROUND 254 | |
1254 #define PNG_CMAP_RGB_BACKGROUND 256 | |
1255 #define PNG_CMAP_RGB_ALPHA_BACKGROUND 216 | |
1256 | |
1257 typedef struct | |
1258 { | |
1259 /* Arguments: */ | |
1260 png_imagep image; | |
1261 png_voidp buffer; | |
1262 png_int_32 row_stride; | |
1263 png_voidp colormap; | |
1264 png_const_colorp background; | |
1265 /* Local variables: */ | |
1266 png_voidp local_row; | |
1267 png_voidp first_row; | |
1268 ptrdiff_t row_bytes; /* step between rows */ | |
1269 int file_encoding; /* E_ values above */ | |
1270 png_fixed_point gamma_to_linear; /* For P_FILE, reciprocal of gamma */ | |
1271 int colormap_processing; /* PNG_CMAP_ values above */ | |
1272 } png_image_read_control; | |
1273 | |
1274 /* Do all the *safe* initialization - 'safe' means that png_error won't be | |
1275 * called, so setting up the jmp_buf is not required. This means that anything | |
1276 * called from here must *not* call png_malloc - it has to call png_malloc_warn | |
1277 * instead so that control is returned safely back to this routine. | |
1278 */ | |
1279 static int | |
1280 png_image_read_init(png_imagep image) | |
1281 { | |
1282 if (image->opaque == NULL) | |
1283 { | |
1284 png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image, | |
1285 png_safe_error, png_safe_warning); | |
1286 | |
1287 /* And set the rest of the structure to NULL to ensure that the various | |
1288 * fields are consistent. | |
1289 */ | |
1290 memset(image, 0, (sizeof *image)); | |
1291 image->version = PNG_IMAGE_VERSION; | |
1292 | |
1293 if (png_ptr != NULL) | |
1294 { | |
1295 png_infop info_ptr = png_create_info_struct(png_ptr); | |
1296 | |
1297 if (info_ptr != NULL) | |
1298 { | |
1299 png_controlp control = png_voidcast(png_controlp, | |
1300 png_malloc_warn(png_ptr, (sizeof *control))); | |
1301 | |
1302 if (control != NULL) | |
1303 { | |
1304 memset(control, 0, (sizeof *control)); | |
1305 | |
1306 control->png_ptr = png_ptr; | |
1307 control->info_ptr = info_ptr; | |
1308 control->for_write = 0; | |
1309 | |
1310 image->opaque = control; | |
1311 return 1; | |
1312 } | |
1313 | |
1314 /* Error clean up */ | |
1315 png_destroy_info_struct(png_ptr, &info_ptr); | |
1316 } | |
1317 | |
1318 png_destroy_read_struct(&png_ptr, NULL, NULL); | |
1319 } | |
1320 | |
1321 return png_image_error(image, "png_image_read: out of memory"); | |
1322 } | |
1323 | |
1324 return png_image_error(image, "png_image_read: opaque pointer not NULL"); | |
1325 } | |
1326 | |
1327 /* Utility to find the base format of a PNG file from a png_struct. */ | |
1328 static png_uint_32 | |
1329 png_image_format(png_structrp png_ptr) | |
1330 { | |
1331 png_uint_32 format = 0; | |
1332 | |
1333 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) | |
1334 format |= PNG_FORMAT_FLAG_COLOR; | |
1335 | |
1336 if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0) | |
1337 format |= PNG_FORMAT_FLAG_ALPHA; | |
1338 | |
1339 /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS | |
1340 * sets the png_struct fields; that's all we are interested in here. The | |
1341 * precise interaction with an app call to png_set_tRNS and PNG file reading | |
1342 * is unclear. | |
1343 */ | |
1344 else if (png_ptr->num_trans > 0) | |
1345 format |= PNG_FORMAT_FLAG_ALPHA; | |
1346 | |
1347 if (png_ptr->bit_depth == 16) | |
1348 format |= PNG_FORMAT_FLAG_LINEAR; | |
1349 | |
1350 if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0) | |
1351 format |= PNG_FORMAT_FLAG_COLORMAP; | |
1352 | |
1353 return format; | |
1354 } | |
1355 | |
1356 /* Is the given gamma significantly different from sRGB? The test is the same | |
1357 * one used in pngrtran.c when deciding whether to do gamma correction. The | |
1358 * arithmetic optimizes the division by using the fact that the inverse of the | |
1359 * file sRGB gamma is 2.2 | |
1360 */ | |
1361 static int | |
1362 png_gamma_not_sRGB(png_fixed_point g) | |
1363 { | |
1364 if (g < PNG_FP_1) | |
1365 { | |
1366 /* An uninitialized gamma is assumed to be sRGB for the simplified API. */ | |
1367 if (g == 0) | |
1368 return 0; | |
1369 | |
1370 return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */); | |
1371 } | |
1372 | |
1373 return 1; | |
1374 } | |
1375 | |
1376 /* Do the main body of a 'png_image_begin_read' function; read the PNG file | |
1377 * header and fill in all the information. This is executed in a safe context, | |
1378 * unlike the init routine above. | |
1379 */ | |
1380 static int | |
1381 png_image_read_header(png_voidp argument) | |
1382 { | |
1383 png_imagep image = png_voidcast(png_imagep, argument); | |
1384 png_structrp png_ptr = image->opaque->png_ptr; | |
1385 png_inforp info_ptr = image->opaque->info_ptr; | |
1386 | |
1387 png_set_benign_errors(png_ptr, 1/*warn*/); | |
1388 png_read_info(png_ptr, info_ptr); | |
1389 | |
1390 /* Do this the fast way; just read directly out of png_struct. */ | |
1391 image->width = png_ptr->width; | |
1392 image->height = png_ptr->height; | |
1393 | |
1394 { | |
1395 png_uint_32 format = png_image_format(png_ptr); | |
1396 | |
1397 image->format = format; | |
1398 | |
1399 #ifdef PNG_COLORSPACE_SUPPORTED | |
1400 /* Does the colorspace match sRGB? If there is no color endpoint | |
1401 * (colorant) information assume yes, otherwise require the | |
1402 * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set. If the | |
1403 * colorspace has been determined to be invalid ignore it. | |
1404 */ | |
1405 if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags | |
1406 & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB| | |
1407 PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS)) | |
1408 image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB; | |
1409 #endif | |
1410 } | |
1411 | |
1412 /* We need the maximum number of entries regardless of the format the | |
1413 * application sets here. | |
1414 */ | |
1415 { | |
1416 png_uint_32 cmap_entries; | |
1417 | |
1418 switch (png_ptr->color_type) | |
1419 { | |
1420 case PNG_COLOR_TYPE_GRAY: | |
1421 cmap_entries = 1U << png_ptr->bit_depth; | |
1422 break; | |
1423 | |
1424 case PNG_COLOR_TYPE_PALETTE: | |
1425 cmap_entries = png_ptr->num_palette; | |
1426 break; | |
1427 | |
1428 default: | |
1429 cmap_entries = 256; | |
1430 break; | |
1431 } | |
1432 | |
1433 if (cmap_entries > 256) | |
1434 cmap_entries = 256; | |
1435 | |
1436 image->colormap_entries = cmap_entries; | |
1437 } | |
1438 | |
1439 return 1; | |
1440 } | |
1441 | |
1442 #ifdef PNG_STDIO_SUPPORTED | |
1443 int PNGAPI | |
1444 png_image_begin_read_from_stdio(png_imagep image, FILE* file) | |
1445 { | |
1446 if (image != NULL && image->version == PNG_IMAGE_VERSION) | |
1447 { | |
1448 if (file != NULL) | |
1449 { | |
1450 if (png_image_read_init(image) != 0) | |
1451 { | |
1452 /* This is slightly evil, but png_init_io doesn't do anything other | |
1453 * than this and we haven't changed the standard IO functions so | |
1454 * this saves a 'safe' function. | |
1455 */ | |
1456 image->opaque->png_ptr->io_ptr = file; | |
1457 return png_safe_execute(image, png_image_read_header, image); | |
1458 } | |
1459 } | |
1460 | |
1461 else | |
1462 return png_image_error(image, | |
1463 "png_image_begin_read_from_stdio: invalid argument"); | |
1464 } | |
1465 | |
1466 else if (image != NULL) | |
1467 return png_image_error(image, | |
1468 "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION"); | |
1469 | |
1470 return 0; | |
1471 } | |
1472 | |
1473 int PNGAPI | |
1474 png_image_begin_read_from_file(png_imagep image, const char *file_name) | |
1475 { | |
1476 if (image != NULL && image->version == PNG_IMAGE_VERSION) | |
1477 { | |
1478 if (file_name != NULL) | |
1479 { | |
1480 FILE *fp = fopen(file_name, "rb"); | |
1481 | |
1482 if (fp != NULL) | |
1483 { | |
1484 if (png_image_read_init(image) != 0) | |
1485 { | |
1486 image->opaque->png_ptr->io_ptr = fp; | |
1487 image->opaque->owned_file = 1; | |
1488 return png_safe_execute(image, png_image_read_header, image); | |
1489 } | |
1490 | |
1491 /* Clean up: just the opened file. */ | |
1492 (void)fclose(fp); | |
1493 } | |
1494 | |
1495 else | |
1496 return png_image_error(image, strerror(errno)); | |
1497 } | |
1498 | |
1499 else | |
1500 return png_image_error(image, | |
1501 "png_image_begin_read_from_file: invalid argument"); | |
1502 } | |
1503 | |
1504 else if (image != NULL) | |
1505 return png_image_error(image, | |
1506 "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION"); | |
1507 | |
1508 return 0; | |
1509 } | |
1510 #endif /* STDIO */ | |
1511 | |
1512 static void PNGCBAPI | |
1513 png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need) | |
1514 { | |
1515 if (png_ptr != NULL) | |
1516 { | |
1517 png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr); | |
1518 if (image != NULL) | |
1519 { | |
1520 png_controlp cp = image->opaque; | |
1521 if (cp != NULL) | |
1522 { | |
1523 png_const_bytep memory = cp->memory; | |
1524 png_size_t size = cp->size; | |
1525 | |
1526 if (memory != NULL && size >= need) | |
1527 { | |
1528 memcpy(out, memory, need); | |
1529 cp->memory = memory + need; | |
1530 cp->size = size - need; | |
1531 return; | |
1532 } | |
1533 | |
1534 png_error(png_ptr, "read beyond end of data"); | |
1535 } | |
1536 } | |
1537 | |
1538 png_error(png_ptr, "invalid memory read"); | |
1539 } | |
1540 } | |
1541 | |
1542 int PNGAPI png_image_begin_read_from_memory(png_imagep image, | |
1543 png_const_voidp memory, png_size_t size) | |
1544 { | |
1545 if (image != NULL && image->version == PNG_IMAGE_VERSION) | |
1546 { | |
1547 if (memory != NULL && size > 0) | |
1548 { | |
1549 if (png_image_read_init(image) != 0) | |
1550 { | |
1551 /* Now set the IO functions to read from the memory buffer and | |
1552 * store it into io_ptr. Again do this in-place to avoid calling a | |
1553 * libpng function that requires error handling. | |
1554 */ | |
1555 image->opaque->memory = png_voidcast(png_const_bytep, memory); | |
1556 image->opaque->size = size; | |
1557 image->opaque->png_ptr->io_ptr = image; | |
1558 image->opaque->png_ptr->read_data_fn = png_image_memory_read; | |
1559 | |
1560 return png_safe_execute(image, png_image_read_header, image); | |
1561 } | |
1562 } | |
1563 | |
1564 else | |
1565 return png_image_error(image, | |
1566 "png_image_begin_read_from_memory: invalid argument"); | |
1567 } | |
1568 | |
1569 else if (image != NULL) | |
1570 return png_image_error(image, | |
1571 "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION"); | |
1572 | |
1573 return 0; | |
1574 } | |
1575 | |
1576 /* Utility function to skip chunks that are not used by the simplified image | |
1577 * read functions and an appropriate macro to call it. | |
1578 */ | |
1579 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED | |
1580 static void | |
1581 png_image_skip_unused_chunks(png_structrp png_ptr) | |
1582 { | |
1583 /* Prepare the reader to ignore all recognized chunks whose data will not | |
1584 * be used, i.e., all chunks recognized by libpng except for those | |
1585 * involved in basic image reading: | |
1586 * | |
1587 * IHDR, PLTE, IDAT, IEND | |
1588 * | |
1589 * Or image data handling: | |
1590 * | |
1591 * tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT. | |
1592 * | |
1593 * This provides a small performance improvement and eliminates any | |
1594 * potential vulnerability to security problems in the unused chunks. | |
1595 * | |
1596 * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored | |
1597 * too. This allows the simplified API to be compiled without iCCP support, | |
1598 * however if the support is there the chunk is still checked to detect | |
1599 * errors (which are unfortunately quite common.) | |
1600 */ | |
1601 { | |
1602 static PNG_CONST png_byte chunks_to_process[] = { | |
1603 98, 75, 71, 68, '\0', /* bKGD */ | |
1604 99, 72, 82, 77, '\0', /* cHRM */ | |
1605 103, 65, 77, 65, '\0', /* gAMA */ | |
1606 # ifdef PNG_READ_iCCP_SUPPORTED | |
1607 105, 67, 67, 80, '\0', /* iCCP */ | |
1608 # endif | |
1609 115, 66, 73, 84, '\0', /* sBIT */ | |
1610 115, 82, 71, 66, '\0', /* sRGB */ | |
1611 }; | |
1612 | |
1613 /* Ignore unknown chunks and all other chunks except for the | |
1614 * IHDR, PLTE, tRNS, IDAT, and IEND chunks. | |
1615 */ | |
1616 png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER, | |
1617 NULL, -1); | |
1618 | |
1619 /* But do not ignore image data handling chunks */ | |
1620 png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT, | |
1621 chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5); | |
1622 } | |
1623 } | |
1624 | |
1625 # define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p) | |
1626 #else | |
1627 # define PNG_SKIP_CHUNKS(p) ((void)0) | |
1628 #endif /* HANDLE_AS_UNKNOWN */ | |
1629 | |
1630 /* The following macro gives the exact rounded answer for all values in the | |
1631 * range 0..255 (it actually divides by 51.2, but the rounding still generates | |
1632 * the correct numbers 0..5 | |
1633 */ | |
1634 #define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8) | |
1635 | |
1636 /* Utility functions to make particular color-maps */ | |
1637 static void | |
1638 set_file_encoding(png_image_read_control *display) | |
1639 { | |
1640 png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma; | |
1641 if (png_gamma_significant(g) != 0) | |
1642 { | |
1643 if (png_gamma_not_sRGB(g) != 0) | |
1644 { | |
1645 display->file_encoding = P_FILE; | |
1646 display->gamma_to_linear = png_reciprocal(g); | |
1647 } | |
1648 | |
1649 else | |
1650 display->file_encoding = P_sRGB; | |
1651 } | |
1652 | |
1653 else | |
1654 display->file_encoding = P_LINEAR8; | |
1655 } | |
1656 | |
1657 static unsigned int | |
1658 decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding) | |
1659 { | |
1660 if (encoding == P_FILE) /* double check */ | |
1661 encoding = display->file_encoding; | |
1662 | |
1663 if (encoding == P_NOTSET) /* must be the file encoding */ | |
1664 { | |
1665 set_file_encoding(display); | |
1666 encoding = display->file_encoding; | |
1667 } | |
1668 | |
1669 switch (encoding) | |
1670 { | |
1671 case P_FILE: | |
1672 value = png_gamma_16bit_correct(value*257, display->gamma_to_linear); | |
1673 break; | |
1674 | |
1675 case P_sRGB: | |
1676 value = png_sRGB_table[value]; | |
1677 break; | |
1678 | |
1679 case P_LINEAR: | |
1680 break; | |
1681 | |
1682 case P_LINEAR8: | |
1683 value *= 257; | |
1684 break; | |
1685 | |
1686 #ifdef __GNUC__ | |
1687 default: | |
1688 png_error(display->image->opaque->png_ptr, | |
1689 "unexpected encoding (internal error)"); | |
1690 #endif | |
1691 } | |
1692 | |
1693 return value; | |
1694 } | |
1695 | |
1696 static png_uint_32 | |
1697 png_colormap_compose(png_image_read_control *display, | |
1698 png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha, | |
1699 png_uint_32 background, int encoding) | |
1700 { | |
1701 /* The file value is composed on the background, the background has the given | |
1702 * encoding and so does the result, the file is encoded with P_FILE and the | |
1703 * file and alpha are 8-bit values. The (output) encoding will always be | |
1704 * P_LINEAR or P_sRGB. | |
1705 */ | |
1706 png_uint_32 f = decode_gamma(display, foreground, foreground_encoding); | |
1707 png_uint_32 b = decode_gamma(display, background, encoding); | |
1708 | |
1709 /* The alpha is always an 8-bit value (it comes from the palette), the value | |
1710 * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires. | |
1711 */ | |
1712 f = f * alpha + b * (255-alpha); | |
1713 | |
1714 if (encoding == P_LINEAR) | |
1715 { | |
1716 /* Scale to 65535; divide by 255, approximately (in fact this is extremely | |
1717 * accurate, it divides by 255.00000005937181414556, with no overflow.) | |
1718 */ | |
1719 f *= 257; /* Now scaled by 65535 */ | |
1720 f += f >> 16; | |
1721 f = (f+32768) >> 16; | |
1722 } | |
1723 | |
1724 else /* P_sRGB */ | |
1725 f = PNG_sRGB_FROM_LINEAR(f); | |
1726 | |
1727 return f; | |
1728 } | |
1729 | |
1730 /* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must | |
1731 * be 8-bit. | |
1732 */ | |
1733 static void | |
1734 png_create_colormap_entry(png_image_read_control *display, | |
1735 png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue, | |
1736 png_uint_32 alpha, int encoding) | |
1737 { | |
1738 png_imagep image = display->image; | |
1739 const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ? | |
1740 P_LINEAR : P_sRGB; | |
1741 const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 && | |
1742 (red != green || green != blue); | |
1743 | |
1744 if (ip > 255) | |
1745 png_error(image->opaque->png_ptr, "color-map index out of range"); | |
1746 | |
1747 /* Update the cache with whether the file gamma is significantly different | |
1748 * from sRGB. | |
1749 */ | |
1750 if (encoding == P_FILE) | |
1751 { | |
1752 if (display->file_encoding == P_NOTSET) | |
1753 set_file_encoding(display); | |
1754 | |
1755 /* Note that the cached value may be P_FILE too, but if it is then the | |
1756 * gamma_to_linear member has been set. | |
1757 */ | |
1758 encoding = display->file_encoding; | |
1759 } | |
1760 | |
1761 if (encoding == P_FILE) | |
1762 { | |
1763 png_fixed_point g = display->gamma_to_linear; | |
1764 | |
1765 red = png_gamma_16bit_correct(red*257, g); | |
1766 green = png_gamma_16bit_correct(green*257, g); | |
1767 blue = png_gamma_16bit_correct(blue*257, g); | |
1768 | |
1769 if (convert_to_Y != 0 || output_encoding == P_LINEAR) | |
1770 { | |
1771 alpha *= 257; | |
1772 encoding = P_LINEAR; | |
1773 } | |
1774 | |
1775 else | |
1776 { | |
1777 red = PNG_sRGB_FROM_LINEAR(red * 255); | |
1778 green = PNG_sRGB_FROM_LINEAR(green * 255); | |
1779 blue = PNG_sRGB_FROM_LINEAR(blue * 255); | |
1780 encoding = P_sRGB; | |
1781 } | |
1782 } | |
1783 | |
1784 else if (encoding == P_LINEAR8) | |
1785 { | |
1786 /* This encoding occurs quite frequently in test cases because PngSuite | |
1787 * includes a gAMA 1.0 chunk with most images. | |
1788 */ | |
1789 red *= 257; | |
1790 green *= 257; | |
1791 blue *= 257; | |
1792 alpha *= 257; | |
1793 encoding = P_LINEAR; | |
1794 } | |
1795 | |
1796 else if (encoding == P_sRGB && | |
1797 (convert_to_Y != 0 || output_encoding == P_LINEAR)) | |
1798 { | |
1799 /* The values are 8-bit sRGB values, but must be converted to 16-bit | |
1800 * linear. | |
1801 */ | |
1802 red = png_sRGB_table[red]; | |
1803 green = png_sRGB_table[green]; | |
1804 blue = png_sRGB_table[blue]; | |
1805 alpha *= 257; | |
1806 encoding = P_LINEAR; | |
1807 } | |
1808 | |
1809 /* This is set if the color isn't gray but the output is. */ | |
1810 if (encoding == P_LINEAR) | |
1811 { | |
1812 if (convert_to_Y != 0) | |
1813 { | |
1814 /* NOTE: these values are copied from png_do_rgb_to_gray */ | |
1815 png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green + | |
1816 (png_uint_32)2366 * blue; | |
1817 | |
1818 if (output_encoding == P_LINEAR) | |
1819 y = (y + 16384) >> 15; | |
1820 | |
1821 else | |
1822 { | |
1823 /* y is scaled by 32768, we need it scaled by 255: */ | |
1824 y = (y + 128) >> 8; | |
1825 y *= 255; | |
1826 y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7); | |
1827 alpha = PNG_DIV257(alpha); | |
1828 encoding = P_sRGB; | |
1829 } | |
1830 | |
1831 blue = red = green = y; | |
1832 } | |
1833 | |
1834 else if (output_encoding == P_sRGB) | |
1835 { | |
1836 red = PNG_sRGB_FROM_LINEAR(red * 255); | |
1837 green = PNG_sRGB_FROM_LINEAR(green * 255); | |
1838 blue = PNG_sRGB_FROM_LINEAR(blue * 255); | |
1839 alpha = PNG_DIV257(alpha); | |
1840 encoding = P_sRGB; | |
1841 } | |
1842 } | |
1843 | |
1844 if (encoding != output_encoding) | |
1845 png_error(image->opaque->png_ptr, "bad encoding (internal error)"); | |
1846 | |
1847 /* Store the value. */ | |
1848 { | |
1849 # ifdef PNG_FORMAT_AFIRST_SUPPORTED | |
1850 const int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 && | |
1851 (image->format & PNG_FORMAT_FLAG_ALPHA) != 0; | |
1852 # else | |
1853 # define afirst 0 | |
1854 # endif | |
1855 # ifdef PNG_FORMAT_BGR_SUPPORTED | |
1856 const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0; | |
1857 # else | |
1858 # define bgr 0 | |
1859 # endif | |
1860 | |
1861 if (output_encoding == P_LINEAR) | |
1862 { | |
1863 png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap); | |
1864 | |
1865 entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format); | |
1866 | |
1867 /* The linear 16-bit values must be pre-multiplied by the alpha channel | |
1868 * value, if less than 65535 (this is, effectively, composite on black | |
1869 * if the alpha channel is removed.) | |
1870 */ | |
1871 switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format)) | |
1872 { | |
1873 case 4: | |
1874 entry[afirst ? 0 : 3] = (png_uint_16)alpha; | |
1875 /* FALL THROUGH */ | |
1876 | |
1877 case 3: | |
1878 if (alpha < 65535) | |
1879 { | |
1880 if (alpha > 0) | |
1881 { | |
1882 blue = (blue * alpha + 32767U)/65535U; | |
1883 green = (green * alpha + 32767U)/65535U; | |
1884 red = (red * alpha + 32767U)/65535U; | |
1885 } | |
1886 | |
1887 else | |
1888 red = green = blue = 0; | |
1889 } | |
1890 entry[afirst + (2 ^ bgr)] = (png_uint_16)blue; | |
1891 entry[afirst + 1] = (png_uint_16)green; | |
1892 entry[afirst + bgr] = (png_uint_16)red; | |
1893 break; | |
1894 | |
1895 case 2: | |
1896 entry[1 ^ afirst] = (png_uint_16)alpha; | |
1897 /* FALL THROUGH */ | |
1898 | |
1899 case 1: | |
1900 if (alpha < 65535) | |
1901 { | |
1902 if (alpha > 0) | |
1903 green = (green * alpha + 32767U)/65535U; | |
1904 | |
1905 else | |
1906 green = 0; | |
1907 } | |
1908 entry[afirst] = (png_uint_16)green; | |
1909 break; | |
1910 | |
1911 default: | |
1912 break; | |
1913 } | |
1914 } | |
1915 | |
1916 else /* output encoding is P_sRGB */ | |
1917 { | |
1918 png_bytep entry = png_voidcast(png_bytep, display->colormap); | |
1919 | |
1920 entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format); | |
1921 | |
1922 switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format)) | |
1923 { | |
1924 case 4: | |
1925 entry[afirst ? 0 : 3] = (png_byte)alpha; | |
1926 case 3: | |
1927 entry[afirst + (2 ^ bgr)] = (png_byte)blue; | |
1928 entry[afirst + 1] = (png_byte)green; | |
1929 entry[afirst + bgr] = (png_byte)red; | |
1930 break; | |
1931 | |
1932 case 2: | |
1933 entry[1 ^ afirst] = (png_byte)alpha; | |
1934 case 1: | |
1935 entry[afirst] = (png_byte)green; | |
1936 break; | |
1937 | |
1938 default: | |
1939 break; | |
1940 } | |
1941 } | |
1942 | |
1943 # ifdef afirst | |
1944 # undef afirst | |
1945 # endif | |
1946 # ifdef bgr | |
1947 # undef bgr | |
1948 # endif | |
1949 } | |
1950 } | |
1951 | |
1952 static int | |
1953 make_gray_file_colormap(png_image_read_control *display) | |
1954 { | |
1955 unsigned int i; | |
1956 | |
1957 for (i=0; i<256; ++i) | |
1958 png_create_colormap_entry(display, i, i, i, i, 255, P_FILE); | |
1959 | |
1960 return i; | |
1961 } | |
1962 | |
1963 static int | |
1964 make_gray_colormap(png_image_read_control *display) | |
1965 { | |
1966 unsigned int i; | |
1967 | |
1968 for (i=0; i<256; ++i) | |
1969 png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB); | |
1970 | |
1971 return i; | |
1972 } | |
1973 #define PNG_GRAY_COLORMAP_ENTRIES 256 | |
1974 | |
1975 static int | |
1976 make_ga_colormap(png_image_read_control *display) | |
1977 { | |
1978 unsigned int i, a; | |
1979 | |
1980 /* Alpha is retained, the output will be a color-map with entries | |
1981 * selected by six levels of alpha. One transparent entry, 6 gray | |
1982 * levels for all the intermediate alpha values, leaving 230 entries | |
1983 * for the opaque grays. The color-map entries are the six values | |
1984 * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the | |
1985 * relevant entry. | |
1986 * | |
1987 * if (alpha > 229) // opaque | |
1988 * { | |
1989 * // The 231 entries are selected to make the math below work: | |
1990 * base = 0; | |
1991 * entry = (231 * gray + 128) >> 8; | |
1992 * } | |
1993 * else if (alpha < 26) // transparent | |
1994 * { | |
1995 * base = 231; | |
1996 * entry = 0; | |
1997 * } | |
1998 * else // partially opaque | |
1999 * { | |
2000 * base = 226 + 6 * PNG_DIV51(alpha); | |
2001 * entry = PNG_DIV51(gray); | |
2002 * } | |
2003 */ | |
2004 i = 0; | |
2005 while (i < 231) | |
2006 { | |
2007 unsigned int gray = (i * 256 + 115) / 231; | |
2008 png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB); | |
2009 } | |
2010 | |
2011 /* 255 is used here for the component values for consistency with the code | |
2012 * that undoes premultiplication in pngwrite.c. | |
2013 */ | |
2014 png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB); | |
2015 | |
2016 for (a=1; a<5; ++a) | |
2017 { | |
2018 unsigned int g; | |
2019 | |
2020 for (g=0; g<6; ++g) | |
2021 png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51, | |
2022 P_sRGB); | |
2023 } | |
2024 | |
2025 return i; | |
2026 } | |
2027 | |
2028 #define PNG_GA_COLORMAP_ENTRIES 256 | |
2029 | |
2030 static int | |
2031 make_rgb_colormap(png_image_read_control *display) | |
2032 { | |
2033 unsigned int i, r; | |
2034 | |
2035 /* Build a 6x6x6 opaque RGB cube */ | |
2036 for (i=r=0; r<6; ++r) | |
2037 { | |
2038 unsigned int g; | |
2039 | |
2040 for (g=0; g<6; ++g) | |
2041 { | |
2042 unsigned int b; | |
2043 | |
2044 for (b=0; b<6; ++b) | |
2045 png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255, | |
2046 P_sRGB); | |
2047 } | |
2048 } | |
2049 | |
2050 return i; | |
2051 } | |
2052 | |
2053 #define PNG_RGB_COLORMAP_ENTRIES 216 | |
2054 | |
2055 /* Return a palette index to the above palette given three 8-bit sRGB values. */ | |
2056 #define PNG_RGB_INDEX(r,g,b) \ | |
2057 ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b))) | |
2058 | |
2059 static int | |
2060 png_image_read_colormap(png_voidp argument) | |
2061 { | |
2062 png_image_read_control *display = | |
2063 png_voidcast(png_image_read_control*, argument); | |
2064 const png_imagep image = display->image; | |
2065 | |
2066 const png_structrp png_ptr = image->opaque->png_ptr; | |
2067 const png_uint_32 output_format = image->format; | |
2068 const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ? | |
2069 P_LINEAR : P_sRGB; | |
2070 | |
2071 unsigned int cmap_entries; | |
2072 unsigned int output_processing; /* Output processing option */ | |
2073 unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */ | |
2074 | |
2075 /* Background information; the background color and the index of this color | |
2076 * in the color-map if it exists (else 256). | |
2077 */ | |
2078 unsigned int background_index = 256; | |
2079 png_uint_32 back_r, back_g, back_b; | |
2080 | |
2081 /* Flags to accumulate things that need to be done to the input. */ | |
2082 int expand_tRNS = 0; | |
2083 | |
2084 /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is | |
2085 * very difficult to do, the results look awful, and it is difficult to see | |
2086 * what possible use it is because the application can't control the | |
2087 * color-map. | |
2088 */ | |
2089 if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 || | |
2090 png_ptr->num_trans > 0) /* alpha in input */ && | |
2091 ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */) | |
2092 { | |
2093 if (output_encoding == P_LINEAR) /* compose on black */ | |
2094 back_b = back_g = back_r = 0; | |
2095 | |
2096 else if (display->background == NULL /* no way to remove it */) | |
2097 png_error(png_ptr, | |
2098 "a background color must be supplied to remove alpha/transparency"); | |
2099 | |
2100 /* Get a copy of the background color (this avoids repeating the checks | |
2101 * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the | |
2102 * output format. | |
2103 */ | |
2104 else | |
2105 { | |
2106 back_g = display->background->green; | |
2107 if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0) | |
2108 { | |
2109 back_r = display->background->red; | |
2110 back_b = display->background->blue; | |
2111 } | |
2112 else | |
2113 back_b = back_r = back_g; | |
2114 } | |
2115 } | |
2116 | |
2117 else if (output_encoding == P_LINEAR) | |
2118 back_b = back_r = back_g = 65535; | |
2119 | |
2120 else | |
2121 back_b = back_r = back_g = 255; | |
2122 | |
2123 /* Default the input file gamma if required - this is necessary because | |
2124 * libpng assumes that if no gamma information is present the data is in the | |
2125 * output format, but the simplified API deduces the gamma from the input | |
2126 * format. | |
2127 */ | |
2128 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0) | |
2129 { | |
2130 /* Do this directly, not using the png_colorspace functions, to ensure | |
2131 * that it happens even if the colorspace is invalid (though probably if | |
2132 * it is the setting will be ignored) Note that the same thing can be | |
2133 * achieved at the application interface with png_set_gAMA. | |
2134 */ | |
2135 if (png_ptr->bit_depth == 16 && | |
2136 (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0) | |
2137 png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR; | |
2138 | |
2139 else | |
2140 png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE; | |
2141 | |
2142 png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA; | |
2143 } | |
2144 | |
2145 /* Decide what to do based on the PNG color type of the input data. The | |
2146 * utility function png_create_colormap_entry deals with most aspects of the | |
2147 * output transformations; this code works out how to produce bytes of | |
2148 * color-map entries from the original format. | |
2149 */ | |
2150 switch (png_ptr->color_type) | |
2151 { | |
2152 case PNG_COLOR_TYPE_GRAY: | |
2153 if (png_ptr->bit_depth <= 8) | |
2154 { | |
2155 /* There at most 256 colors in the output, regardless of | |
2156 * transparency. | |
2157 */ | |
2158 unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0; | |
2159 | |
2160 cmap_entries = 1U << png_ptr->bit_depth; | |
2161 if (cmap_entries > image->colormap_entries) | |
2162 png_error(png_ptr, "gray[8] color-map: too few entries"); | |
2163 | |
2164 step = 255 / (cmap_entries - 1); | |
2165 output_processing = PNG_CMAP_NONE; | |
2166 | |
2167 /* If there is a tRNS chunk then this either selects a transparent | |
2168 * value or, if the output has no alpha, the background color. | |
2169 */ | |
2170 if (png_ptr->num_trans > 0) | |
2171 { | |
2172 trans = png_ptr->trans_color.gray; | |
2173 | |
2174 if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) | |
2175 back_alpha = output_encoding == P_LINEAR ? 65535 : 255; | |
2176 } | |
2177 | |
2178 /* png_create_colormap_entry just takes an RGBA and writes the | |
2179 * corresponding color-map entry using the format from 'image', | |
2180 * including the required conversion to sRGB or linear as | |
2181 * appropriate. The input values are always either sRGB (if the | |
2182 * gamma correction flag is 0) or 0..255 scaled file encoded values | |
2183 * (if the function must gamma correct them). | |
2184 */ | |
2185 for (i=val=0; i<cmap_entries; ++i, val += step) | |
2186 { | |
2187 /* 'i' is a file value. While this will result in duplicated | |
2188 * entries for 8-bit non-sRGB encoded files it is necessary to | |
2189 * have non-gamma corrected values to do tRNS handling. | |
2190 */ | |
2191 if (i != trans) | |
2192 png_create_colormap_entry(display, i, val, val, val, 255, | |
2193 P_FILE/*8-bit with file gamma*/); | |
2194 | |
2195 /* Else this entry is transparent. The colors don't matter if | |
2196 * there is an alpha channel (back_alpha == 0), but it does no | |
2197 * harm to pass them in; the values are not set above so this | |
2198 * passes in white. | |
2199 * | |
2200 * NOTE: this preserves the full precision of the application | |
2201 * supplied background color when it is used. | |
2202 */ | |
2203 else | |
2204 png_create_colormap_entry(display, i, back_r, back_g, back_b, | |
2205 back_alpha, output_encoding); | |
2206 } | |
2207 | |
2208 /* We need libpng to preserve the original encoding. */ | |
2209 data_encoding = P_FILE; | |
2210 | |
2211 /* The rows from libpng, while technically gray values, are now also | |
2212 * color-map indices; however, they may need to be expanded to 1 | |
2213 * byte per pixel. This is what png_set_packing does (i.e., it | |
2214 * unpacks the bit values into bytes.) | |
2215 */ | |
2216 if (png_ptr->bit_depth < 8) | |
2217 png_set_packing(png_ptr); | |
2218 } | |
2219 | |
2220 else /* bit depth is 16 */ | |
2221 { | |
2222 /* The 16-bit input values can be converted directly to 8-bit gamma | |
2223 * encoded values; however, if a tRNS chunk is present 257 color-map | |
2224 * entries are required. This means that the extra entry requires | |
2225 * special processing; add an alpha channel, sacrifice gray level | |
2226 * 254 and convert transparent (alpha==0) entries to that. | |
2227 * | |
2228 * Use libpng to chop the data to 8 bits. Convert it to sRGB at the | |
2229 * same time to minimize quality loss. If a tRNS chunk is present | |
2230 * this means libpng must handle it too; otherwise it is impossible | |
2231 * to do the exact match on the 16-bit value. | |
2232 * | |
2233 * If the output has no alpha channel *and* the background color is | |
2234 * gray then it is possible to let libpng handle the substitution by | |
2235 * ensuring that the corresponding gray level matches the background | |
2236 * color exactly. | |
2237 */ | |
2238 data_encoding = P_sRGB; | |
2239 | |
2240 if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries) | |
2241 png_error(png_ptr, "gray[16] color-map: too few entries"); | |
2242 | |
2243 cmap_entries = make_gray_colormap(display); | |
2244 | |
2245 if (png_ptr->num_trans > 0) | |
2246 { | |
2247 unsigned int back_alpha; | |
2248 | |
2249 if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
2250 back_alpha = 0; | |
2251 | |
2252 else | |
2253 { | |
2254 if (back_r == back_g && back_g == back_b) | |
2255 { | |
2256 /* Background is gray; no special processing will be | |
2257 * required. | |
2258 */ | |
2259 png_color_16 c; | |
2260 png_uint_32 gray = back_g; | |
2261 | |
2262 if (output_encoding == P_LINEAR) | |
2263 { | |
2264 gray = PNG_sRGB_FROM_LINEAR(gray * 255); | |
2265 | |
2266 /* And make sure the corresponding palette entry | |
2267 * matches. | |
2268 */ | |
2269 png_create_colormap_entry(display, gray, back_g, back_g, | |
2270 back_g, 65535, P_LINEAR); | |
2271 } | |
2272 | |
2273 /* The background passed to libpng, however, must be the | |
2274 * sRGB value. | |
2275 */ | |
2276 c.index = 0; /*unused*/ | |
2277 c.gray = c.red = c.green = c.blue = (png_uint_16)gray; | |
2278 | |
2279 /* NOTE: does this work without expanding tRNS to alpha? | |
2280 * It should be the color->gray case below apparently | |
2281 * doesn't. | |
2282 */ | |
2283 png_set_background_fixed(png_ptr, &c, | |
2284 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, | |
2285 0/*gamma: not used*/); | |
2286 | |
2287 output_processing = PNG_CMAP_NONE; | |
2288 break; | |
2289 } | |
2290 #ifdef __COVERITY__ | |
2291 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR) | |
2292 * here. | |
2293 */ | |
2294 back_alpha = 255; | |
2295 #else | |
2296 back_alpha = output_encoding == P_LINEAR ? 65535 : 255; | |
2297 #endif | |
2298 } | |
2299 | |
2300 /* output_processing means that the libpng-processed row will be | |
2301 * 8-bit GA and it has to be processing to single byte color-map | |
2302 * values. Entry 254 is replaced by either a completely | |
2303 * transparent entry or by the background color at full | |
2304 * precision (and the background color is not a simple gray | |
2305 * level in this case.) | |
2306 */ | |
2307 expand_tRNS = 1; | |
2308 output_processing = PNG_CMAP_TRANS; | |
2309 background_index = 254; | |
2310 | |
2311 /* And set (overwrite) color-map entry 254 to the actual | |
2312 * background color at full precision. | |
2313 */ | |
2314 png_create_colormap_entry(display, 254, back_r, back_g, back_b, | |
2315 back_alpha, output_encoding); | |
2316 } | |
2317 | |
2318 else | |
2319 output_processing = PNG_CMAP_NONE; | |
2320 } | |
2321 break; | |
2322 | |
2323 case PNG_COLOR_TYPE_GRAY_ALPHA: | |
2324 /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum | |
2325 * of 65536 combinations. If, however, the alpha channel is to be | |
2326 * removed there are only 256 possibilities if the background is gray. | |
2327 * (Otherwise there is a subset of the 65536 possibilities defined by | |
2328 * the triangle between black, white and the background color.) | |
2329 * | |
2330 * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to | |
2331 * worry about tRNS matching - tRNS is ignored if there is an alpha | |
2332 * channel. | |
2333 */ | |
2334 data_encoding = P_sRGB; | |
2335 | |
2336 if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
2337 { | |
2338 if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries) | |
2339 png_error(png_ptr, "gray+alpha color-map: too few entries"); | |
2340 | |
2341 cmap_entries = make_ga_colormap(display); | |
2342 | |
2343 background_index = PNG_CMAP_GA_BACKGROUND; | |
2344 output_processing = PNG_CMAP_GA; | |
2345 } | |
2346 | |
2347 else /* alpha is removed */ | |
2348 { | |
2349 /* Alpha must be removed as the PNG data is processed when the | |
2350 * background is a color because the G and A channels are | |
2351 * independent and the vector addition (non-parallel vectors) is a | |
2352 * 2-D problem. | |
2353 * | |
2354 * This can be reduced to the same algorithm as above by making a | |
2355 * colormap containing gray levels (for the opaque grays), a | |
2356 * background entry (for a transparent pixel) and a set of four six | |
2357 * level color values, one set for each intermediate alpha value. | |
2358 * See the comments in make_ga_colormap for how this works in the | |
2359 * per-pixel processing. | |
2360 * | |
2361 * If the background is gray, however, we only need a 256 entry gray | |
2362 * level color map. It is sufficient to make the entry generated | |
2363 * for the background color be exactly the color specified. | |
2364 */ | |
2365 if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 || | |
2366 (back_r == back_g && back_g == back_b)) | |
2367 { | |
2368 /* Background is gray; no special processing will be required. */ | |
2369 png_color_16 c; | |
2370 png_uint_32 gray = back_g; | |
2371 | |
2372 if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries) | |
2373 png_error(png_ptr, "gray-alpha color-map: too few entries"); | |
2374 | |
2375 cmap_entries = make_gray_colormap(display); | |
2376 | |
2377 if (output_encoding == P_LINEAR) | |
2378 { | |
2379 gray = PNG_sRGB_FROM_LINEAR(gray * 255); | |
2380 | |
2381 /* And make sure the corresponding palette entry matches. */ | |
2382 png_create_colormap_entry(display, gray, back_g, back_g, | |
2383 back_g, 65535, P_LINEAR); | |
2384 } | |
2385 | |
2386 /* The background passed to libpng, however, must be the sRGB | |
2387 * value. | |
2388 */ | |
2389 c.index = 0; /*unused*/ | |
2390 c.gray = c.red = c.green = c.blue = (png_uint_16)gray; | |
2391 | |
2392 png_set_background_fixed(png_ptr, &c, | |
2393 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, | |
2394 0/*gamma: not used*/); | |
2395 | |
2396 output_processing = PNG_CMAP_NONE; | |
2397 } | |
2398 | |
2399 else | |
2400 { | |
2401 png_uint_32 i, a; | |
2402 | |
2403 /* This is the same as png_make_ga_colormap, above, except that | |
2404 * the entries are all opaque. | |
2405 */ | |
2406 if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries) | |
2407 png_error(png_ptr, "ga-alpha color-map: too few entries"); | |
2408 | |
2409 i = 0; | |
2410 while (i < 231) | |
2411 { | |
2412 png_uint_32 gray = (i * 256 + 115) / 231; | |
2413 png_create_colormap_entry(display, i++, gray, gray, gray, | |
2414 255, P_sRGB); | |
2415 } | |
2416 | |
2417 /* NOTE: this preserves the full precision of the application | |
2418 * background color. | |
2419 */ | |
2420 background_index = i; | |
2421 png_create_colormap_entry(display, i++, back_r, back_g, back_b, | |
2422 #ifdef __COVERITY__ | |
2423 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR) | |
2424 * here. | |
2425 */ 255U, | |
2426 #else | |
2427 output_encoding == P_LINEAR ? 65535U : 255U, | |
2428 #endif | |
2429 output_encoding); | |
2430 | |
2431 /* For non-opaque input composite on the sRGB background - this | |
2432 * requires inverting the encoding for each component. The input | |
2433 * is still converted to the sRGB encoding because this is a | |
2434 * reasonable approximate to the logarithmic curve of human | |
2435 * visual sensitivity, at least over the narrow range which PNG | |
2436 * represents. Consequently 'G' is always sRGB encoded, while | |
2437 * 'A' is linear. We need the linear background colors. | |
2438 */ | |
2439 if (output_encoding == P_sRGB) /* else already linear */ | |
2440 { | |
2441 /* This may produce a value not exactly matching the | |
2442 * background, but that's ok because these numbers are only | |
2443 * used when alpha != 0 | |
2444 */ | |
2445 back_r = png_sRGB_table[back_r]; | |
2446 back_g = png_sRGB_table[back_g]; | |
2447 back_b = png_sRGB_table[back_b]; | |
2448 } | |
2449 | |
2450 for (a=1; a<5; ++a) | |
2451 { | |
2452 unsigned int g; | |
2453 | |
2454 /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled | |
2455 * by an 8-bit alpha value (0..255). | |
2456 */ | |
2457 png_uint_32 alpha = 51 * a; | |
2458 png_uint_32 back_rx = (255-alpha) * back_r; | |
2459 png_uint_32 back_gx = (255-alpha) * back_g; | |
2460 png_uint_32 back_bx = (255-alpha) * back_b; | |
2461 | |
2462 for (g=0; g<6; ++g) | |
2463 { | |
2464 png_uint_32 gray = png_sRGB_table[g*51] * alpha; | |
2465 | |
2466 png_create_colormap_entry(display, i++, | |
2467 PNG_sRGB_FROM_LINEAR(gray + back_rx), | |
2468 PNG_sRGB_FROM_LINEAR(gray + back_gx), | |
2469 PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB); | |
2470 } | |
2471 } | |
2472 | |
2473 cmap_entries = i; | |
2474 output_processing = PNG_CMAP_GA; | |
2475 } | |
2476 } | |
2477 break; | |
2478 | |
2479 case PNG_COLOR_TYPE_RGB: | |
2480 case PNG_COLOR_TYPE_RGB_ALPHA: | |
2481 /* Exclude the case where the output is gray; we can always handle this | |
2482 * with the cases above. | |
2483 */ | |
2484 if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0) | |
2485 { | |
2486 /* The color-map will be grayscale, so we may as well convert the | |
2487 * input RGB values to a simple grayscale and use the grayscale | |
2488 * code above. | |
2489 * | |
2490 * NOTE: calling this apparently damages the recognition of the | |
2491 * transparent color in background color handling; call | |
2492 * png_set_tRNS_to_alpha before png_set_background_fixed. | |
2493 */ | |
2494 png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1, | |
2495 -1); | |
2496 data_encoding = P_sRGB; | |
2497 | |
2498 /* The output will now be one or two 8-bit gray or gray+alpha | |
2499 * channels. The more complex case arises when the input has alpha. | |
2500 */ | |
2501 if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || | |
2502 png_ptr->num_trans > 0) && | |
2503 (output_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
2504 { | |
2505 /* Both input and output have an alpha channel, so no background | |
2506 * processing is required; just map the GA bytes to the right | |
2507 * color-map entry. | |
2508 */ | |
2509 expand_tRNS = 1; | |
2510 | |
2511 if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries) | |
2512 png_error(png_ptr, "rgb[ga] color-map: too few entries"); | |
2513 | |
2514 cmap_entries = make_ga_colormap(display); | |
2515 background_index = PNG_CMAP_GA_BACKGROUND; | |
2516 output_processing = PNG_CMAP_GA; | |
2517 } | |
2518 | |
2519 else | |
2520 { | |
2521 /* Either the input or the output has no alpha channel, so there | |
2522 * will be no non-opaque pixels in the color-map; it will just be | |
2523 * grayscale. | |
2524 */ | |
2525 if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries) | |
2526 png_error(png_ptr, "rgb[gray] color-map: too few entries"); | |
2527 | |
2528 /* Ideally this code would use libpng to do the gamma correction, | |
2529 * but if an input alpha channel is to be removed we will hit the | |
2530 * libpng bug in gamma+compose+rgb-to-gray (the double gamma | |
2531 * correction bug). Fix this by dropping the gamma correction in | |
2532 * this case and doing it in the palette; this will result in | |
2533 * duplicate palette entries, but that's better than the | |
2534 * alternative of double gamma correction. | |
2535 */ | |
2536 if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || | |
2537 png_ptr->num_trans > 0) && | |
2538 png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0) | |
2539 { | |
2540 cmap_entries = make_gray_file_colormap(display); | |
2541 data_encoding = P_FILE; | |
2542 } | |
2543 | |
2544 else | |
2545 cmap_entries = make_gray_colormap(display); | |
2546 | |
2547 /* But if the input has alpha or transparency it must be removed | |
2548 */ | |
2549 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || | |
2550 png_ptr->num_trans > 0) | |
2551 { | |
2552 png_color_16 c; | |
2553 png_uint_32 gray = back_g; | |
2554 | |
2555 /* We need to ensure that the application background exists in | |
2556 * the colormap and that completely transparent pixels map to | |
2557 * it. Achieve this simply by ensuring that the entry | |
2558 * selected for the background really is the background color. | |
2559 */ | |
2560 if (data_encoding == P_FILE) /* from the fixup above */ | |
2561 { | |
2562 /* The app supplied a gray which is in output_encoding, we | |
2563 * need to convert it to a value of the input (P_FILE) | |
2564 * encoding then set this palette entry to the required | |
2565 * output encoding. | |
2566 */ | |
2567 if (output_encoding == P_sRGB) | |
2568 gray = png_sRGB_table[gray]; /* now P_LINEAR */ | |
2569 | |
2570 gray = PNG_DIV257(png_gamma_16bit_correct(gray, | |
2571 png_ptr->colorspace.gamma)); /* now P_FILE */ | |
2572 | |
2573 /* And make sure the corresponding palette entry contains | |
2574 * exactly the required sRGB value. | |
2575 */ | |
2576 png_create_colormap_entry(display, gray, back_g, back_g, | |
2577 back_g, 0/*unused*/, output_encoding); | |
2578 } | |
2579 | |
2580 else if (output_encoding == P_LINEAR) | |
2581 { | |
2582 gray = PNG_sRGB_FROM_LINEAR(gray * 255); | |
2583 | |
2584 /* And make sure the corresponding palette entry matches. | |
2585 */ | |
2586 png_create_colormap_entry(display, gray, back_g, back_g, | |
2587 back_g, 0/*unused*/, P_LINEAR); | |
2588 } | |
2589 | |
2590 /* The background passed to libpng, however, must be the | |
2591 * output (normally sRGB) value. | |
2592 */ | |
2593 c.index = 0; /*unused*/ | |
2594 c.gray = c.red = c.green = c.blue = (png_uint_16)gray; | |
2595 | |
2596 /* NOTE: the following is apparently a bug in libpng. Without | |
2597 * it the transparent color recognition in | |
2598 * png_set_background_fixed seems to go wrong. | |
2599 */ | |
2600 expand_tRNS = 1; | |
2601 png_set_background_fixed(png_ptr, &c, | |
2602 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, | |
2603 0/*gamma: not used*/); | |
2604 } | |
2605 | |
2606 output_processing = PNG_CMAP_NONE; | |
2607 } | |
2608 } | |
2609 | |
2610 else /* output is color */ | |
2611 { | |
2612 /* We could use png_quantize here so long as there is no transparent | |
2613 * color or alpha; png_quantize ignores alpha. Easier overall just | |
2614 * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube. | |
2615 * Consequently we always want libpng to produce sRGB data. | |
2616 */ | |
2617 data_encoding = P_sRGB; | |
2618 | |
2619 /* Is there any transparency or alpha? */ | |
2620 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || | |
2621 png_ptr->num_trans > 0) | |
2622 { | |
2623 /* Is there alpha in the output too? If so all four channels are | |
2624 * processed into a special RGB cube with alpha support. | |
2625 */ | |
2626 if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
2627 { | |
2628 png_uint_32 r; | |
2629 | |
2630 if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries) | |
2631 png_error(png_ptr, "rgb+alpha color-map: too few entries"); | |
2632 | |
2633 cmap_entries = make_rgb_colormap(display); | |
2634 | |
2635 /* Add a transparent entry. */ | |
2636 png_create_colormap_entry(display, cmap_entries, 255, 255, | |
2637 255, 0, P_sRGB); | |
2638 | |
2639 /* This is stored as the background index for the processing | |
2640 * algorithm. | |
2641 */ | |
2642 background_index = cmap_entries++; | |
2643 | |
2644 /* Add 27 r,g,b entries each with alpha 0.5. */ | |
2645 for (r=0; r<256; r = (r << 1) | 0x7f) | |
2646 { | |
2647 png_uint_32 g; | |
2648 | |
2649 for (g=0; g<256; g = (g << 1) | 0x7f) | |
2650 { | |
2651 png_uint_32 b; | |
2652 | |
2653 /* This generates components with the values 0, 127 and | |
2654 * 255 | |
2655 */ | |
2656 for (b=0; b<256; b = (b << 1) | 0x7f) | |
2657 png_create_colormap_entry(display, cmap_entries++, | |
2658 r, g, b, 128, P_sRGB); | |
2659 } | |
2660 } | |
2661 | |
2662 expand_tRNS = 1; | |
2663 output_processing = PNG_CMAP_RGB_ALPHA; | |
2664 } | |
2665 | |
2666 else | |
2667 { | |
2668 /* Alpha/transparency must be removed. The background must | |
2669 * exist in the color map (achieved by setting adding it after | |
2670 * the 666 color-map). If the standard processing code will | |
2671 * pick up this entry automatically that's all that is | |
2672 * required; libpng can be called to do the background | |
2673 * processing. | |
2674 */ | |
2675 unsigned int sample_size = | |
2676 PNG_IMAGE_SAMPLE_SIZE(output_format); | |
2677 png_uint_32 r, g, b; /* sRGB background */ | |
2678 | |
2679 if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries) | |
2680 png_error(png_ptr, "rgb-alpha color-map: too few entries"); | |
2681 | |
2682 cmap_entries = make_rgb_colormap(display); | |
2683 | |
2684 png_create_colormap_entry(display, cmap_entries, back_r, | |
2685 back_g, back_b, 0/*unused*/, output_encoding); | |
2686 | |
2687 if (output_encoding == P_LINEAR) | |
2688 { | |
2689 r = PNG_sRGB_FROM_LINEAR(back_r * 255); | |
2690 g = PNG_sRGB_FROM_LINEAR(back_g * 255); | |
2691 b = PNG_sRGB_FROM_LINEAR(back_b * 255); | |
2692 } | |
2693 | |
2694 else | |
2695 { | |
2696 r = back_r; | |
2697 g = back_g; | |
2698 b = back_g; | |
2699 } | |
2700 | |
2701 /* Compare the newly-created color-map entry with the one the | |
2702 * PNG_CMAP_RGB algorithm will use. If the two entries don't | |
2703 * match, add the new one and set this as the background | |
2704 * index. | |
2705 */ | |
2706 if (memcmp((png_const_bytep)display->colormap + | |
2707 sample_size * cmap_entries, | |
2708 (png_const_bytep)display->colormap + | |
2709 sample_size * PNG_RGB_INDEX(r,g,b), | |
2710 sample_size) != 0) | |
2711 { | |
2712 /* The background color must be added. */ | |
2713 background_index = cmap_entries++; | |
2714 | |
2715 /* Add 27 r,g,b entries each with created by composing with | |
2716 * the background at alpha 0.5. | |
2717 */ | |
2718 for (r=0; r<256; r = (r << 1) | 0x7f) | |
2719 { | |
2720 for (g=0; g<256; g = (g << 1) | 0x7f) | |
2721 { | |
2722 /* This generates components with the values 0, 127 | |
2723 * and 255 | |
2724 */ | |
2725 for (b=0; b<256; b = (b << 1) | 0x7f) | |
2726 png_create_colormap_entry(display, cmap_entries++, | |
2727 png_colormap_compose(display, r, P_sRGB, 128, | |
2728 back_r, output_encoding), | |
2729 png_colormap_compose(display, g, P_sRGB, 128, | |
2730 back_g, output_encoding), | |
2731 png_colormap_compose(display, b, P_sRGB, 128, | |
2732 back_b, output_encoding), | |
2733 0/*unused*/, output_encoding); | |
2734 } | |
2735 } | |
2736 | |
2737 expand_tRNS = 1; | |
2738 output_processing = PNG_CMAP_RGB_ALPHA; | |
2739 } | |
2740 | |
2741 else /* background color is in the standard color-map */ | |
2742 { | |
2743 png_color_16 c; | |
2744 | |
2745 c.index = 0; /*unused*/ | |
2746 c.red = (png_uint_16)back_r; | |
2747 c.gray = c.green = (png_uint_16)back_g; | |
2748 c.blue = (png_uint_16)back_b; | |
2749 | |
2750 png_set_background_fixed(png_ptr, &c, | |
2751 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, | |
2752 0/*gamma: not used*/); | |
2753 | |
2754 output_processing = PNG_CMAP_RGB; | |
2755 } | |
2756 } | |
2757 } | |
2758 | |
2759 else /* no alpha or transparency in the input */ | |
2760 { | |
2761 /* Alpha in the output is irrelevant, simply map the opaque input | |
2762 * pixels to the 6x6x6 color-map. | |
2763 */ | |
2764 if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries) | |
2765 png_error(png_ptr, "rgb color-map: too few entries"); | |
2766 | |
2767 cmap_entries = make_rgb_colormap(display); | |
2768 output_processing = PNG_CMAP_RGB; | |
2769 } | |
2770 } | |
2771 break; | |
2772 | |
2773 case PNG_COLOR_TYPE_PALETTE: | |
2774 /* It's already got a color-map. It may be necessary to eliminate the | |
2775 * tRNS entries though. | |
2776 */ | |
2777 { | |
2778 unsigned int num_trans = png_ptr->num_trans; | |
2779 png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL; | |
2780 png_const_colorp colormap = png_ptr->palette; | |
2781 const int do_background = trans != NULL && | |
2782 (output_format & PNG_FORMAT_FLAG_ALPHA) == 0; | |
2783 unsigned int i; | |
2784 | |
2785 /* Just in case: */ | |
2786 if (trans == NULL) | |
2787 num_trans = 0; | |
2788 | |
2789 output_processing = PNG_CMAP_NONE; | |
2790 data_encoding = P_FILE; /* Don't change from color-map indices */ | |
2791 cmap_entries = png_ptr->num_palette; | |
2792 if (cmap_entries > 256) | |
2793 cmap_entries = 256; | |
2794 | |
2795 if (cmap_entries > image->colormap_entries) | |
2796 png_error(png_ptr, "palette color-map: too few entries"); | |
2797 | |
2798 for (i=0; i < cmap_entries; ++i) | |
2799 { | |
2800 if (do_background != 0 && i < num_trans && trans[i] < 255) | |
2801 { | |
2802 if (trans[i] == 0) | |
2803 png_create_colormap_entry(display, i, back_r, back_g, | |
2804 back_b, 0, output_encoding); | |
2805 | |
2806 else | |
2807 { | |
2808 /* Must compose the PNG file color in the color-map entry | |
2809 * on the sRGB color in 'back'. | |
2810 */ | |
2811 png_create_colormap_entry(display, i, | |
2812 png_colormap_compose(display, colormap[i].red, P_FILE, | |
2813 trans[i], back_r, output_encoding), | |
2814 png_colormap_compose(display, colormap[i].green, P_FILE, | |
2815 trans[i], back_g, output_encoding), | |
2816 png_colormap_compose(display, colormap[i].blue, P_FILE, | |
2817 trans[i], back_b, output_encoding), | |
2818 output_encoding == P_LINEAR ? trans[i] * 257U : | |
2819 trans[i], | |
2820 output_encoding); | |
2821 } | |
2822 } | |
2823 | |
2824 else | |
2825 png_create_colormap_entry(display, i, colormap[i].red, | |
2826 colormap[i].green, colormap[i].blue, | |
2827 i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/); | |
2828 } | |
2829 | |
2830 /* The PNG data may have indices packed in fewer than 8 bits, it | |
2831 * must be expanded if so. | |
2832 */ | |
2833 if (png_ptr->bit_depth < 8) | |
2834 png_set_packing(png_ptr); | |
2835 } | |
2836 break; | |
2837 | |
2838 default: | |
2839 png_error(png_ptr, "invalid PNG color type"); | |
2840 /*NOT REACHED*/ | |
2841 } | |
2842 | |
2843 /* Now deal with the output processing */ | |
2844 if (expand_tRNS != 0 && png_ptr->num_trans > 0 && | |
2845 (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0) | |
2846 png_set_tRNS_to_alpha(png_ptr); | |
2847 | |
2848 switch (data_encoding) | |
2849 { | |
2850 case P_sRGB: | |
2851 /* Change to 8-bit sRGB */ | |
2852 png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB); | |
2853 /* FALL THROUGH */ | |
2854 | |
2855 case P_FILE: | |
2856 if (png_ptr->bit_depth > 8) | |
2857 png_set_scale_16(png_ptr); | |
2858 break; | |
2859 | |
2860 #ifdef __GNUC__ | |
2861 default: | |
2862 png_error(png_ptr, "bad data option (internal error)"); | |
2863 #endif | |
2864 } | |
2865 | |
2866 if (cmap_entries > 256 || cmap_entries > image->colormap_entries) | |
2867 png_error(png_ptr, "color map overflow (BAD internal error)"); | |
2868 | |
2869 image->colormap_entries = cmap_entries; | |
2870 | |
2871 /* Double check using the recorded background index */ | |
2872 switch (output_processing) | |
2873 { | |
2874 case PNG_CMAP_NONE: | |
2875 if (background_index != PNG_CMAP_NONE_BACKGROUND) | |
2876 goto bad_background; | |
2877 break; | |
2878 | |
2879 case PNG_CMAP_GA: | |
2880 if (background_index != PNG_CMAP_GA_BACKGROUND) | |
2881 goto bad_background; | |
2882 break; | |
2883 | |
2884 case PNG_CMAP_TRANS: | |
2885 if (background_index >= cmap_entries || | |
2886 background_index != PNG_CMAP_TRANS_BACKGROUND) | |
2887 goto bad_background; | |
2888 break; | |
2889 | |
2890 case PNG_CMAP_RGB: | |
2891 if (background_index != PNG_CMAP_RGB_BACKGROUND) | |
2892 goto bad_background; | |
2893 break; | |
2894 | |
2895 case PNG_CMAP_RGB_ALPHA: | |
2896 if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND) | |
2897 goto bad_background; | |
2898 break; | |
2899 | |
2900 default: | |
2901 png_error(png_ptr, "bad processing option (internal error)"); | |
2902 | |
2903 bad_background: | |
2904 png_error(png_ptr, "bad background index (internal error)"); | |
2905 } | |
2906 | |
2907 display->colormap_processing = output_processing; | |
2908 | |
2909 return 1/*ok*/; | |
2910 } | |
2911 | |
2912 /* The final part of the color-map read called from png_image_finish_read. */ | |
2913 static int | |
2914 png_image_read_and_map(png_voidp argument) | |
2915 { | |
2916 png_image_read_control *display = png_voidcast(png_image_read_control*, | |
2917 argument); | |
2918 png_imagep image = display->image; | |
2919 png_structrp png_ptr = image->opaque->png_ptr; | |
2920 int passes; | |
2921 | |
2922 /* Called when the libpng data must be transformed into the color-mapped | |
2923 * form. There is a local row buffer in display->local and this routine must | |
2924 * do the interlace handling. | |
2925 */ | |
2926 switch (png_ptr->interlaced) | |
2927 { | |
2928 case PNG_INTERLACE_NONE: | |
2929 passes = 1; | |
2930 break; | |
2931 | |
2932 case PNG_INTERLACE_ADAM7: | |
2933 passes = PNG_INTERLACE_ADAM7_PASSES; | |
2934 break; | |
2935 | |
2936 default: | |
2937 png_error(png_ptr, "unknown interlace type"); | |
2938 } | |
2939 | |
2940 { | |
2941 png_uint_32 height = image->height; | |
2942 png_uint_32 width = image->width; | |
2943 int proc = display->colormap_processing; | |
2944 png_bytep first_row = png_voidcast(png_bytep, display->first_row); | |
2945 ptrdiff_t step_row = display->row_bytes; | |
2946 int pass; | |
2947 | |
2948 for (pass = 0; pass < passes; ++pass) | |
2949 { | |
2950 unsigned int startx, stepx, stepy; | |
2951 png_uint_32 y; | |
2952 | |
2953 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) | |
2954 { | |
2955 /* The row may be empty for a short image: */ | |
2956 if (PNG_PASS_COLS(width, pass) == 0) | |
2957 continue; | |
2958 | |
2959 startx = PNG_PASS_START_COL(pass); | |
2960 stepx = PNG_PASS_COL_OFFSET(pass); | |
2961 y = PNG_PASS_START_ROW(pass); | |
2962 stepy = PNG_PASS_ROW_OFFSET(pass); | |
2963 } | |
2964 | |
2965 else | |
2966 { | |
2967 y = 0; | |
2968 startx = 0; | |
2969 stepx = stepy = 1; | |
2970 } | |
2971 | |
2972 for (; y<height; y += stepy) | |
2973 { | |
2974 png_bytep inrow = png_voidcast(png_bytep, display->local_row); | |
2975 png_bytep outrow = first_row + y * step_row; | |
2976 png_const_bytep end_row = outrow + width; | |
2977 | |
2978 /* Read read the libpng data into the temporary buffer. */ | |
2979 png_read_row(png_ptr, inrow, NULL); | |
2980 | |
2981 /* Now process the row according to the processing option, note | |
2982 * that the caller verifies that the format of the libpng output | |
2983 * data is as required. | |
2984 */ | |
2985 outrow += startx; | |
2986 switch (proc) | |
2987 { | |
2988 case PNG_CMAP_GA: | |
2989 for (; outrow < end_row; outrow += stepx) | |
2990 { | |
2991 /* The data is always in the PNG order */ | |
2992 unsigned int gray = *inrow++; | |
2993 unsigned int alpha = *inrow++; | |
2994 unsigned int entry; | |
2995 | |
2996 /* NOTE: this code is copied as a comment in | |
2997 * make_ga_colormap above. Please update the | |
2998 * comment if you change this code! | |
2999 */ | |
3000 if (alpha > 229) /* opaque */ | |
3001 { | |
3002 entry = (231 * gray + 128) >> 8; | |
3003 } | |
3004 else if (alpha < 26) /* transparent */ | |
3005 { | |
3006 entry = 231; | |
3007 } | |
3008 else /* partially opaque */ | |
3009 { | |
3010 entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray); | |
3011 } | |
3012 | |
3013 *outrow = (png_byte)entry; | |
3014 } | |
3015 break; | |
3016 | |
3017 case PNG_CMAP_TRANS: | |
3018 for (; outrow < end_row; outrow += stepx) | |
3019 { | |
3020 png_byte gray = *inrow++; | |
3021 png_byte alpha = *inrow++; | |
3022 | |
3023 if (alpha == 0) | |
3024 *outrow = PNG_CMAP_TRANS_BACKGROUND; | |
3025 | |
3026 else if (gray != PNG_CMAP_TRANS_BACKGROUND) | |
3027 *outrow = gray; | |
3028 | |
3029 else | |
3030 *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1); | |
3031 } | |
3032 break; | |
3033 | |
3034 case PNG_CMAP_RGB: | |
3035 for (; outrow < end_row; outrow += stepx) | |
3036 { | |
3037 *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]); | |
3038 inrow += 3; | |
3039 } | |
3040 break; | |
3041 | |
3042 case PNG_CMAP_RGB_ALPHA: | |
3043 for (; outrow < end_row; outrow += stepx) | |
3044 { | |
3045 unsigned int alpha = inrow[3]; | |
3046 | |
3047 /* Because the alpha entries only hold alpha==0.5 values | |
3048 * split the processing at alpha==0.25 (64) and 0.75 | |
3049 * (196). | |
3050 */ | |
3051 | |
3052 if (alpha >= 196) | |
3053 *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], | |
3054 inrow[2]); | |
3055 | |
3056 else if (alpha < 64) | |
3057 *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND; | |
3058 | |
3059 else | |
3060 { | |
3061 /* Likewise there are three entries for each of r, g | |
3062 * and b. We could select the entry by popcount on | |
3063 * the top two bits on those architectures that | |
3064 * support it, this is what the code below does, | |
3065 * crudely. | |
3066 */ | |
3067 unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1; | |
3068 | |
3069 /* Here are how the values map: | |
3070 * | |
3071 * 0x00 .. 0x3f -> 0 | |
3072 * 0x40 .. 0xbf -> 1 | |
3073 * 0xc0 .. 0xff -> 2 | |
3074 * | |
3075 * So, as above with the explicit alpha checks, the | |
3076 * breakpoints are at 64 and 196. | |
3077 */ | |
3078 if (inrow[0] & 0x80) back_i += 9; /* red */ | |
3079 if (inrow[0] & 0x40) back_i += 9; | |
3080 if (inrow[0] & 0x80) back_i += 3; /* green */ | |
3081 if (inrow[0] & 0x40) back_i += 3; | |
3082 if (inrow[0] & 0x80) back_i += 1; /* blue */ | |
3083 if (inrow[0] & 0x40) back_i += 1; | |
3084 | |
3085 *outrow = (png_byte)back_i; | |
3086 } | |
3087 | |
3088 inrow += 4; | |
3089 } | |
3090 break; | |
3091 | |
3092 default: | |
3093 break; | |
3094 } | |
3095 } | |
3096 } | |
3097 } | |
3098 | |
3099 return 1; | |
3100 } | |
3101 | |
3102 static int | |
3103 png_image_read_colormapped(png_voidp argument) | |
3104 { | |
3105 png_image_read_control *display = png_voidcast(png_image_read_control*, | |
3106 argument); | |
3107 png_imagep image = display->image; | |
3108 png_controlp control = image->opaque; | |
3109 png_structrp png_ptr = control->png_ptr; | |
3110 png_inforp info_ptr = control->info_ptr; | |
3111 | |
3112 int passes = 0; /* As a flag */ | |
3113 | |
3114 PNG_SKIP_CHUNKS(png_ptr); | |
3115 | |
3116 /* Update the 'info' structure and make sure the result is as required; first | |
3117 * make sure to turn on the interlace handling if it will be required | |
3118 * (because it can't be turned on *after* the call to png_read_update_info!) | |
3119 */ | |
3120 if (display->colormap_processing == PNG_CMAP_NONE) | |
3121 passes = png_set_interlace_handling(png_ptr); | |
3122 | |
3123 png_read_update_info(png_ptr, info_ptr); | |
3124 | |
3125 /* The expected output can be deduced from the colormap_processing option. */ | |
3126 switch (display->colormap_processing) | |
3127 { | |
3128 case PNG_CMAP_NONE: | |
3129 /* Output must be one channel and one byte per pixel, the output | |
3130 * encoding can be anything. | |
3131 */ | |
3132 if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE || | |
3133 info_ptr->color_type == PNG_COLOR_TYPE_GRAY) && | |
3134 info_ptr->bit_depth == 8) | |
3135 break; | |
3136 | |
3137 goto bad_output; | |
3138 | |
3139 case PNG_CMAP_TRANS: | |
3140 case PNG_CMAP_GA: | |
3141 /* Output must be two channels and the 'G' one must be sRGB, the latter | |
3142 * can be checked with an exact number because it should have been set | |
3143 * to this number above! | |
3144 */ | |
3145 if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
3146 info_ptr->bit_depth == 8 && | |
3147 png_ptr->screen_gamma == PNG_GAMMA_sRGB && | |
3148 image->colormap_entries == 256) | |
3149 break; | |
3150 | |
3151 goto bad_output; | |
3152 | |
3153 case PNG_CMAP_RGB: | |
3154 /* Output must be 8-bit sRGB encoded RGB */ | |
3155 if (info_ptr->color_type == PNG_COLOR_TYPE_RGB && | |
3156 info_ptr->bit_depth == 8 && | |
3157 png_ptr->screen_gamma == PNG_GAMMA_sRGB && | |
3158 image->colormap_entries == 216) | |
3159 break; | |
3160 | |
3161 goto bad_output; | |
3162 | |
3163 case PNG_CMAP_RGB_ALPHA: | |
3164 /* Output must be 8-bit sRGB encoded RGBA */ | |
3165 if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA && | |
3166 info_ptr->bit_depth == 8 && | |
3167 png_ptr->screen_gamma == PNG_GAMMA_sRGB && | |
3168 image->colormap_entries == 244 /* 216 + 1 + 27 */) | |
3169 break; | |
3170 | |
3171 /* goto bad_output; */ | |
3172 /* FALL THROUGH */ | |
3173 | |
3174 default: | |
3175 bad_output: | |
3176 png_error(png_ptr, "bad color-map processing (internal error)"); | |
3177 } | |
3178 | |
3179 /* Now read the rows. Do this here if it is possible to read directly into | |
3180 * the output buffer, otherwise allocate a local row buffer of the maximum | |
3181 * size libpng requires and call the relevant processing routine safely. | |
3182 */ | |
3183 { | |
3184 png_voidp first_row = display->buffer; | |
3185 ptrdiff_t row_bytes = display->row_stride; | |
3186 | |
3187 /* The following expression is designed to work correctly whether it gives | |
3188 * a signed or an unsigned result. | |
3189 */ | |
3190 if (row_bytes < 0) | |
3191 { | |
3192 char *ptr = png_voidcast(char*, first_row); | |
3193 ptr += (image->height-1) * (-row_bytes); | |
3194 first_row = png_voidcast(png_voidp, ptr); | |
3195 } | |
3196 | |
3197 display->first_row = first_row; | |
3198 display->row_bytes = row_bytes; | |
3199 } | |
3200 | |
3201 if (passes == 0) | |
3202 { | |
3203 int result; | |
3204 png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr)); | |
3205 | |
3206 display->local_row = row; | |
3207 result = png_safe_execute(image, png_image_read_and_map, display); | |
3208 display->local_row = NULL; | |
3209 png_free(png_ptr, row); | |
3210 | |
3211 return result; | |
3212 } | |
3213 | |
3214 else | |
3215 { | |
3216 png_alloc_size_t row_bytes = display->row_bytes; | |
3217 | |
3218 while (--passes >= 0) | |
3219 { | |
3220 png_uint_32 y = image->height; | |
3221 png_bytep row = png_voidcast(png_bytep, display->first_row); | |
3222 | |
3223 while (y-- > 0) | |
3224 { | |
3225 png_read_row(png_ptr, row, NULL); | |
3226 row += row_bytes; | |
3227 } | |
3228 } | |
3229 | |
3230 return 1; | |
3231 } | |
3232 } | |
3233 | |
3234 /* Just the row reading part of png_image_read. */ | |
3235 static int | |
3236 png_image_read_composite(png_voidp argument) | |
3237 { | |
3238 png_image_read_control *display = png_voidcast(png_image_read_control*, | |
3239 argument); | |
3240 png_imagep image = display->image; | |
3241 png_structrp png_ptr = image->opaque->png_ptr; | |
3242 int passes; | |
3243 | |
3244 switch (png_ptr->interlaced) | |
3245 { | |
3246 case PNG_INTERLACE_NONE: | |
3247 passes = 1; | |
3248 break; | |
3249 | |
3250 case PNG_INTERLACE_ADAM7: | |
3251 passes = PNG_INTERLACE_ADAM7_PASSES; | |
3252 break; | |
3253 | |
3254 default: | |
3255 png_error(png_ptr, "unknown interlace type"); | |
3256 } | |
3257 | |
3258 { | |
3259 png_uint_32 height = image->height; | |
3260 png_uint_32 width = image->width; | |
3261 ptrdiff_t step_row = display->row_bytes; | |
3262 unsigned int channels = | |
3263 (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1; | |
3264 int pass; | |
3265 | |
3266 for (pass = 0; pass < passes; ++pass) | |
3267 { | |
3268 unsigned int startx, stepx, stepy; | |
3269 png_uint_32 y; | |
3270 | |
3271 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) | |
3272 { | |
3273 /* The row may be empty for a short image: */ | |
3274 if (PNG_PASS_COLS(width, pass) == 0) | |
3275 continue; | |
3276 | |
3277 startx = PNG_PASS_START_COL(pass) * channels; | |
3278 stepx = PNG_PASS_COL_OFFSET(pass) * channels; | |
3279 y = PNG_PASS_START_ROW(pass); | |
3280 stepy = PNG_PASS_ROW_OFFSET(pass); | |
3281 } | |
3282 | |
3283 else | |
3284 { | |
3285 y = 0; | |
3286 startx = 0; | |
3287 stepx = channels; | |
3288 stepy = 1; | |
3289 } | |
3290 | |
3291 for (; y<height; y += stepy) | |
3292 { | |
3293 png_bytep inrow = png_voidcast(png_bytep, display->local_row); | |
3294 png_bytep outrow; | |
3295 png_const_bytep end_row; | |
3296 | |
3297 /* Read the row, which is packed: */ | |
3298 png_read_row(png_ptr, inrow, NULL); | |
3299 | |
3300 outrow = png_voidcast(png_bytep, display->first_row); | |
3301 outrow += y * step_row; | |
3302 end_row = outrow + width * channels; | |
3303 | |
3304 /* Now do the composition on each pixel in this row. */ | |
3305 outrow += startx; | |
3306 for (; outrow < end_row; outrow += stepx) | |
3307 { | |
3308 png_byte alpha = inrow[channels]; | |
3309 | |
3310 if (alpha > 0) /* else no change to the output */ | |
3311 { | |
3312 unsigned int c; | |
3313 | |
3314 for (c=0; c<channels; ++c) | |
3315 { | |
3316 png_uint_32 component = inrow[c]; | |
3317 | |
3318 if (alpha < 255) /* else just use component */ | |
3319 { | |
3320 /* This is PNG_OPTIMIZED_ALPHA, the component value | |
3321 * is a linear 8-bit value. Combine this with the | |
3322 * current outrow[c] value which is sRGB encoded. | |
3323 * Arithmetic here is 16-bits to preserve the output | |
3324 * values correctly. | |
3325 */ | |
3326 component *= 257*255; /* =65535 */ | |
3327 component += (255-alpha)*png_sRGB_table[outrow[c]]; | |
3328 | |
3329 /* So 'component' is scaled by 255*65535 and is | |
3330 * therefore appropriate for the sRGB to linear | |
3331 * conversion table. | |
3332 */ | |
3333 component = PNG_sRGB_FROM_LINEAR(component); | |
3334 } | |
3335 | |
3336 outrow[c] = (png_byte)component; | |
3337 } | |
3338 } | |
3339 | |
3340 inrow += channels+1; /* components and alpha channel */ | |
3341 } | |
3342 } | |
3343 } | |
3344 } | |
3345 | |
3346 return 1; | |
3347 } | |
3348 | |
3349 /* The do_local_background case; called when all the following transforms are to | |
3350 * be done: | |
3351 * | |
3352 * PNG_RGB_TO_GRAY | |
3353 * PNG_COMPOSITE | |
3354 * PNG_GAMMA | |
3355 * | |
3356 * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and | |
3357 * PNG_COMPOSITE code performs gamma correction, so we get double gamma | |
3358 * correction. The fix-up is to prevent the PNG_COMPOSITE operation from | |
3359 * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha | |
3360 * row and handles the removal or pre-multiplication of the alpha channel. | |
3361 */ | |
3362 static int | |
3363 png_image_read_background(png_voidp argument) | |
3364 { | |
3365 png_image_read_control *display = png_voidcast(png_image_read_control*, | |
3366 argument); | |
3367 png_imagep image = display->image; | |
3368 png_structrp png_ptr = image->opaque->png_ptr; | |
3369 png_inforp info_ptr = image->opaque->info_ptr; | |
3370 png_uint_32 height = image->height; | |
3371 png_uint_32 width = image->width; | |
3372 int pass, passes; | |
3373 | |
3374 /* Double check the convoluted logic below. We expect to get here with | |
3375 * libpng doing rgb to gray and gamma correction but background processing | |
3376 * left to the png_image_read_background function. The rows libpng produce | |
3377 * might be 8 or 16-bit but should always have two channels; gray plus alpha. | |
3378 */ | |
3379 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0) | |
3380 png_error(png_ptr, "lost rgb to gray"); | |
3381 | |
3382 if ((png_ptr->transformations & PNG_COMPOSE) != 0) | |
3383 png_error(png_ptr, "unexpected compose"); | |
3384 | |
3385 if (png_get_channels(png_ptr, info_ptr) != 2) | |
3386 png_error(png_ptr, "lost/gained channels"); | |
3387 | |
3388 /* Expect the 8-bit case to always remove the alpha channel */ | |
3389 if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 && | |
3390 (image->format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3391 png_error(png_ptr, "unexpected 8-bit transformation"); | |
3392 | |
3393 switch (png_ptr->interlaced) | |
3394 { | |
3395 case PNG_INTERLACE_NONE: | |
3396 passes = 1; | |
3397 break; | |
3398 | |
3399 case PNG_INTERLACE_ADAM7: | |
3400 passes = PNG_INTERLACE_ADAM7_PASSES; | |
3401 break; | |
3402 | |
3403 default: | |
3404 png_error(png_ptr, "unknown interlace type"); | |
3405 } | |
3406 | |
3407 /* Use direct access to info_ptr here because otherwise the simplified API | |
3408 * would require PNG_EASY_ACCESS_SUPPORTED (just for this.) Note this is | |
3409 * checking the value after libpng expansions, not the original value in the | |
3410 * PNG. | |
3411 */ | |
3412 switch (info_ptr->bit_depth) | |
3413 { | |
3414 case 8: | |
3415 /* 8-bit sRGB gray values with an alpha channel; the alpha channel is | |
3416 * to be removed by composing on a background: either the row if | |
3417 * display->background is NULL or display->background->green if not. | |
3418 * Unlike the code above ALPHA_OPTIMIZED has *not* been done. | |
3419 */ | |
3420 { | |
3421 png_bytep first_row = png_voidcast(png_bytep, display->first_row); | |
3422 ptrdiff_t step_row = display->row_bytes; | |
3423 | |
3424 for (pass = 0; pass < passes; ++pass) | |
3425 { | |
3426 png_bytep row = png_voidcast(png_bytep, | |
3427 display->first_row); | |
3428 unsigned int startx, stepx, stepy; | |
3429 png_uint_32 y; | |
3430 | |
3431 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) | |
3432 { | |
3433 /* The row may be empty for a short image: */ | |
3434 if (PNG_PASS_COLS(width, pass) == 0) | |
3435 continue; | |
3436 | |
3437 startx = PNG_PASS_START_COL(pass); | |
3438 stepx = PNG_PASS_COL_OFFSET(pass); | |
3439 y = PNG_PASS_START_ROW(pass); | |
3440 stepy = PNG_PASS_ROW_OFFSET(pass); | |
3441 } | |
3442 | |
3443 else | |
3444 { | |
3445 y = 0; | |
3446 startx = 0; | |
3447 stepx = stepy = 1; | |
3448 } | |
3449 | |
3450 if (display->background == NULL) | |
3451 { | |
3452 for (; y<height; y += stepy) | |
3453 { | |
3454 png_bytep inrow = png_voidcast(png_bytep, | |
3455 display->local_row); | |
3456 png_bytep outrow = first_row + y * step_row; | |
3457 png_const_bytep end_row = outrow + width; | |
3458 | |
3459 /* Read the row, which is packed: */ | |
3460 png_read_row(png_ptr, inrow, NULL); | |
3461 | |
3462 /* Now do the composition on each pixel in this row. */ | |
3463 outrow += startx; | |
3464 for (; outrow < end_row; outrow += stepx) | |
3465 { | |
3466 png_byte alpha = inrow[1]; | |
3467 | |
3468 if (alpha > 0) /* else no change to the output */ | |
3469 { | |
3470 png_uint_32 component = inrow[0]; | |
3471 | |
3472 if (alpha < 255) /* else just use component */ | |
3473 { | |
3474 /* Since PNG_OPTIMIZED_ALPHA was not set it is | |
3475 * necessary to invert the sRGB transfer | |
3476 * function and multiply the alpha out. | |
3477 */ | |
3478 component = png_sRGB_table[component] * alpha; | |
3479 component += png_sRGB_table[outrow[0]] * | |
3480 (255-alpha); | |
3481 component = PNG_sRGB_FROM_LINEAR(component); | |
3482 } | |
3483 | |
3484 outrow[0] = (png_byte)component; | |
3485 } | |
3486 | |
3487 inrow += 2; /* gray and alpha channel */ | |
3488 } | |
3489 } | |
3490 } | |
3491 | |
3492 else /* constant background value */ | |
3493 { | |
3494 png_byte background8 = display->background->green; | |
3495 png_uint_16 background = png_sRGB_table[background8]; | |
3496 | |
3497 for (; y<height; y += stepy) | |
3498 { | |
3499 png_bytep inrow = png_voidcast(png_bytep, | |
3500 display->local_row); | |
3501 png_bytep outrow = first_row + y * step_row; | |
3502 png_const_bytep end_row = outrow + width; | |
3503 | |
3504 /* Read the row, which is packed: */ | |
3505 png_read_row(png_ptr, inrow, NULL); | |
3506 | |
3507 /* Now do the composition on each pixel in this row. */ | |
3508 outrow += startx; | |
3509 for (; outrow < end_row; outrow += stepx) | |
3510 { | |
3511 png_byte alpha = inrow[1]; | |
3512 | |
3513 if (alpha > 0) /* else use background */ | |
3514 { | |
3515 png_uint_32 component = inrow[0]; | |
3516 | |
3517 if (alpha < 255) /* else just use component */ | |
3518 { | |
3519 component = png_sRGB_table[component] * alpha; | |
3520 component += background * (255-alpha); | |
3521 component = PNG_sRGB_FROM_LINEAR(component); | |
3522 } | |
3523 | |
3524 outrow[0] = (png_byte)component; | |
3525 } | |
3526 | |
3527 else | |
3528 outrow[0] = background8; | |
3529 | |
3530 inrow += 2; /* gray and alpha channel */ | |
3531 } | |
3532 | |
3533 row += display->row_bytes; | |
3534 } | |
3535 } | |
3536 } | |
3537 } | |
3538 break; | |
3539 | |
3540 case 16: | |
3541 /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must | |
3542 * still be done and, maybe, the alpha channel removed. This code also | |
3543 * handles the alpha-first option. | |
3544 */ | |
3545 { | |
3546 png_uint_16p first_row = png_voidcast(png_uint_16p, | |
3547 display->first_row); | |
3548 /* The division by two is safe because the caller passed in a | |
3549 * stride which was multiplied by 2 (below) to get row_bytes. | |
3550 */ | |
3551 ptrdiff_t step_row = display->row_bytes / 2; | |
3552 int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0; | |
3553 unsigned int outchannels = 1+preserve_alpha; | |
3554 int swap_alpha = 0; | |
3555 | |
3556 # ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED | |
3557 if (preserve_alpha != 0 && | |
3558 (image->format & PNG_FORMAT_FLAG_AFIRST) != 0) | |
3559 swap_alpha = 1; | |
3560 # endif | |
3561 | |
3562 for (pass = 0; pass < passes; ++pass) | |
3563 { | |
3564 unsigned int startx, stepx, stepy; | |
3565 png_uint_32 y; | |
3566 | |
3567 /* The 'x' start and step are adjusted to output components here. | |
3568 */ | |
3569 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) | |
3570 { | |
3571 /* The row may be empty for a short image: */ | |
3572 if (PNG_PASS_COLS(width, pass) == 0) | |
3573 continue; | |
3574 | |
3575 startx = PNG_PASS_START_COL(pass) * outchannels; | |
3576 stepx = PNG_PASS_COL_OFFSET(pass) * outchannels; | |
3577 y = PNG_PASS_START_ROW(pass); | |
3578 stepy = PNG_PASS_ROW_OFFSET(pass); | |
3579 } | |
3580 | |
3581 else | |
3582 { | |
3583 y = 0; | |
3584 startx = 0; | |
3585 stepx = outchannels; | |
3586 stepy = 1; | |
3587 } | |
3588 | |
3589 for (; y<height; y += stepy) | |
3590 { | |
3591 png_const_uint_16p inrow; | |
3592 png_uint_16p outrow = first_row + y*step_row; | |
3593 png_uint_16p end_row = outrow + width * outchannels; | |
3594 | |
3595 /* Read the row, which is packed: */ | |
3596 png_read_row(png_ptr, png_voidcast(png_bytep, | |
3597 display->local_row), NULL); | |
3598 inrow = png_voidcast(png_const_uint_16p, display->local_row); | |
3599 | |
3600 /* Now do the pre-multiplication on each pixel in this row. | |
3601 */ | |
3602 outrow += startx; | |
3603 for (; outrow < end_row; outrow += stepx) | |
3604 { | |
3605 png_uint_32 component = inrow[0]; | |
3606 png_uint_16 alpha = inrow[1]; | |
3607 | |
3608 if (alpha > 0) /* else 0 */ | |
3609 { | |
3610 if (alpha < 65535) /* else just use component */ | |
3611 { | |
3612 component *= alpha; | |
3613 component += 32767; | |
3614 component /= 65535; | |
3615 } | |
3616 } | |
3617 | |
3618 else | |
3619 component = 0; | |
3620 | |
3621 outrow[swap_alpha] = (png_uint_16)component; | |
3622 if (preserve_alpha != 0) | |
3623 outrow[1 ^ swap_alpha] = alpha; | |
3624 | |
3625 inrow += 2; /* components and alpha channel */ | |
3626 } | |
3627 } | |
3628 } | |
3629 } | |
3630 break; | |
3631 | |
3632 #ifdef __GNUC__ | |
3633 default: | |
3634 png_error(png_ptr, "unexpected bit depth"); | |
3635 #endif | |
3636 } | |
3637 | |
3638 return 1; | |
3639 } | |
3640 | |
3641 /* The guts of png_image_finish_read as a png_safe_execute callback. */ | |
3642 static int | |
3643 png_image_read_direct(png_voidp argument) | |
3644 { | |
3645 png_image_read_control *display = png_voidcast(png_image_read_control*, | |
3646 argument); | |
3647 png_imagep image = display->image; | |
3648 png_structrp png_ptr = image->opaque->png_ptr; | |
3649 png_inforp info_ptr = image->opaque->info_ptr; | |
3650 | |
3651 png_uint_32 format = image->format; | |
3652 int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0; | |
3653 int do_local_compose = 0; | |
3654 int do_local_background = 0; /* to avoid double gamma correction bug */ | |
3655 int passes = 0; | |
3656 | |
3657 /* Add transforms to ensure the correct output format is produced then check | |
3658 * that the required implementation support is there. Always expand; always | |
3659 * need 8 bits minimum, no palette and expanded tRNS. | |
3660 */ | |
3661 png_set_expand(png_ptr); | |
3662 | |
3663 /* Now check the format to see if it was modified. */ | |
3664 { | |
3665 png_uint_32 base_format = png_image_format(png_ptr) & | |
3666 ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */; | |
3667 png_uint_32 change = format ^ base_format; | |
3668 png_fixed_point output_gamma; | |
3669 int mode; /* alpha mode */ | |
3670 | |
3671 /* Do this first so that we have a record if rgb to gray is happening. */ | |
3672 if ((change & PNG_FORMAT_FLAG_COLOR) != 0) | |
3673 { | |
3674 /* gray<->color transformation required. */ | |
3675 if ((format & PNG_FORMAT_FLAG_COLOR) != 0) | |
3676 png_set_gray_to_rgb(png_ptr); | |
3677 | |
3678 else | |
3679 { | |
3680 /* libpng can't do both rgb to gray and | |
3681 * background/pre-multiplication if there is also significant gamma | |
3682 * correction, because both operations require linear colors and | |
3683 * the code only supports one transform doing the gamma correction. | |
3684 * Handle this by doing the pre-multiplication or background | |
3685 * operation in this code, if necessary. | |
3686 * | |
3687 * TODO: fix this by rewriting pngrtran.c (!) | |
3688 * | |
3689 * For the moment (given that fixing this in pngrtran.c is an | |
3690 * enormous change) 'do_local_background' is used to indicate that | |
3691 * the problem exists. | |
3692 */ | |
3693 if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3694 do_local_background = 1/*maybe*/; | |
3695 | |
3696 png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, | |
3697 PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT); | |
3698 } | |
3699 | |
3700 change &= ~PNG_FORMAT_FLAG_COLOR; | |
3701 } | |
3702 | |
3703 /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise. | |
3704 */ | |
3705 { | |
3706 png_fixed_point input_gamma_default; | |
3707 | |
3708 if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 && | |
3709 (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0) | |
3710 input_gamma_default = PNG_GAMMA_LINEAR; | |
3711 else | |
3712 input_gamma_default = PNG_DEFAULT_sRGB; | |
3713 | |
3714 /* Call png_set_alpha_mode to set the default for the input gamma; the | |
3715 * output gamma is set by a second call below. | |
3716 */ | |
3717 png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default); | |
3718 } | |
3719 | |
3720 if (linear != 0) | |
3721 { | |
3722 /* If there *is* an alpha channel in the input it must be multiplied | |
3723 * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG. | |
3724 */ | |
3725 if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3726 mode = PNG_ALPHA_STANDARD; /* associated alpha */ | |
3727 | |
3728 else | |
3729 mode = PNG_ALPHA_PNG; | |
3730 | |
3731 output_gamma = PNG_GAMMA_LINEAR; | |
3732 } | |
3733 | |
3734 else | |
3735 { | |
3736 mode = PNG_ALPHA_PNG; | |
3737 output_gamma = PNG_DEFAULT_sRGB; | |
3738 } | |
3739 | |
3740 /* If 'do_local_background' is set check for the presence of gamma | |
3741 * correction; this is part of the work-round for the libpng bug | |
3742 * described above. | |
3743 * | |
3744 * TODO: fix libpng and remove this. | |
3745 */ | |
3746 if (do_local_background != 0) | |
3747 { | |
3748 png_fixed_point gtest; | |
3749 | |
3750 /* This is 'png_gamma_threshold' from pngrtran.c; the test used for | |
3751 * gamma correction, the screen gamma hasn't been set on png_struct | |
3752 * yet; it's set below. png_struct::gamma, however, is set to the | |
3753 * final value. | |
3754 */ | |
3755 if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma, | |
3756 PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0) | |
3757 do_local_background = 0; | |
3758 | |
3759 else if (mode == PNG_ALPHA_STANDARD) | |
3760 { | |
3761 do_local_background = 2/*required*/; | |
3762 mode = PNG_ALPHA_PNG; /* prevent libpng doing it */ | |
3763 } | |
3764 | |
3765 /* else leave as 1 for the checks below */ | |
3766 } | |
3767 | |
3768 /* If the bit-depth changes then handle that here. */ | |
3769 if ((change & PNG_FORMAT_FLAG_LINEAR) != 0) | |
3770 { | |
3771 if (linear != 0 /*16-bit output*/) | |
3772 png_set_expand_16(png_ptr); | |
3773 | |
3774 else /* 8-bit output */ | |
3775 png_set_scale_16(png_ptr); | |
3776 | |
3777 change &= ~PNG_FORMAT_FLAG_LINEAR; | |
3778 } | |
3779 | |
3780 /* Now the background/alpha channel changes. */ | |
3781 if ((change & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3782 { | |
3783 /* Removing an alpha channel requires composition for the 8-bit | |
3784 * formats; for the 16-bit it is already done, above, by the | |
3785 * pre-multiplication and the channel just needs to be stripped. | |
3786 */ | |
3787 if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3788 { | |
3789 /* If RGB->gray is happening the alpha channel must be left and the | |
3790 * operation completed locally. | |
3791 * | |
3792 * TODO: fix libpng and remove this. | |
3793 */ | |
3794 if (do_local_background != 0) | |
3795 do_local_background = 2/*required*/; | |
3796 | |
3797 /* 16-bit output: just remove the channel */ | |
3798 else if (linear != 0) /* compose on black (well, pre-multiply) */ | |
3799 png_set_strip_alpha(png_ptr); | |
3800 | |
3801 /* 8-bit output: do an appropriate compose */ | |
3802 else if (display->background != NULL) | |
3803 { | |
3804 png_color_16 c; | |
3805 | |
3806 c.index = 0; /*unused*/ | |
3807 c.red = display->background->red; | |
3808 c.green = display->background->green; | |
3809 c.blue = display->background->blue; | |
3810 c.gray = display->background->green; | |
3811 | |
3812 /* This is always an 8-bit sRGB value, using the 'green' channel | |
3813 * for gray is much better than calculating the luminance here; | |
3814 * we can get off-by-one errors in that calculation relative to | |
3815 * the app expectations and that will show up in transparent | |
3816 * pixels. | |
3817 */ | |
3818 png_set_background_fixed(png_ptr, &c, | |
3819 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, | |
3820 0/*gamma: not used*/); | |
3821 } | |
3822 | |
3823 else /* compose on row: implemented below. */ | |
3824 { | |
3825 do_local_compose = 1; | |
3826 /* This leaves the alpha channel in the output, so it has to be | |
3827 * removed by the code below. Set the encoding to the 'OPTIMIZE' | |
3828 * one so the code only has to hack on the pixels that require | |
3829 * composition. | |
3830 */ | |
3831 mode = PNG_ALPHA_OPTIMIZED; | |
3832 } | |
3833 } | |
3834 | |
3835 else /* output needs an alpha channel */ | |
3836 { | |
3837 /* This is tricky because it happens before the swap operation has | |
3838 * been accomplished; however, the swap does *not* swap the added | |
3839 * alpha channel (weird API), so it must be added in the correct | |
3840 * place. | |
3841 */ | |
3842 png_uint_32 filler; /* opaque filler */ | |
3843 int where; | |
3844 | |
3845 if (linear != 0) | |
3846 filler = 65535; | |
3847 | |
3848 else | |
3849 filler = 255; | |
3850 | |
3851 # ifdef PNG_FORMAT_AFIRST_SUPPORTED | |
3852 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0) | |
3853 { | |
3854 where = PNG_FILLER_BEFORE; | |
3855 change &= ~PNG_FORMAT_FLAG_AFIRST; | |
3856 } | |
3857 | |
3858 else | |
3859 # endif | |
3860 where = PNG_FILLER_AFTER; | |
3861 | |
3862 png_set_add_alpha(png_ptr, filler, where); | |
3863 } | |
3864 | |
3865 /* This stops the (irrelevant) call to swap_alpha below. */ | |
3866 change &= ~PNG_FORMAT_FLAG_ALPHA; | |
3867 } | |
3868 | |
3869 /* Now set the alpha mode correctly; this is always done, even if there is | |
3870 * no alpha channel in either the input or the output because it correctly | |
3871 * sets the output gamma. | |
3872 */ | |
3873 png_set_alpha_mode_fixed(png_ptr, mode, output_gamma); | |
3874 | |
3875 # ifdef PNG_FORMAT_BGR_SUPPORTED | |
3876 if ((change & PNG_FORMAT_FLAG_BGR) != 0) | |
3877 { | |
3878 /* Check only the output format; PNG is never BGR; don't do this if | |
3879 * the output is gray, but fix up the 'format' value in that case. | |
3880 */ | |
3881 if ((format & PNG_FORMAT_FLAG_COLOR) != 0) | |
3882 png_set_bgr(png_ptr); | |
3883 | |
3884 else | |
3885 format &= ~PNG_FORMAT_FLAG_BGR; | |
3886 | |
3887 change &= ~PNG_FORMAT_FLAG_BGR; | |
3888 } | |
3889 # endif | |
3890 | |
3891 # ifdef PNG_FORMAT_AFIRST_SUPPORTED | |
3892 if ((change & PNG_FORMAT_FLAG_AFIRST) != 0) | |
3893 { | |
3894 /* Only relevant if there is an alpha channel - it's particularly | |
3895 * important to handle this correctly because do_local_compose may | |
3896 * be set above and then libpng will keep the alpha channel for this | |
3897 * code to remove. | |
3898 */ | |
3899 if ((format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3900 { | |
3901 /* Disable this if doing a local background, | |
3902 * TODO: remove this when local background is no longer required. | |
3903 */ | |
3904 if (do_local_background != 2) | |
3905 png_set_swap_alpha(png_ptr); | |
3906 } | |
3907 | |
3908 else | |
3909 format &= ~PNG_FORMAT_FLAG_AFIRST; | |
3910 | |
3911 change &= ~PNG_FORMAT_FLAG_AFIRST; | |
3912 } | |
3913 # endif | |
3914 | |
3915 /* If the *output* is 16-bit then we need to check for a byte-swap on this | |
3916 * architecture. | |
3917 */ | |
3918 if (linear != 0) | |
3919 { | |
3920 PNG_CONST png_uint_16 le = 0x0001; | |
3921 | |
3922 if ((*(png_const_bytep) & le) != 0) | |
3923 png_set_swap(png_ptr); | |
3924 } | |
3925 | |
3926 /* If change is not now 0 some transformation is missing - error out. */ | |
3927 if (change != 0) | |
3928 png_error(png_ptr, "png_read_image: unsupported transformation"); | |
3929 } | |
3930 | |
3931 PNG_SKIP_CHUNKS(png_ptr); | |
3932 | |
3933 /* Update the 'info' structure and make sure the result is as required; first | |
3934 * make sure to turn on the interlace handling if it will be required | |
3935 * (because it can't be turned on *after* the call to png_read_update_info!) | |
3936 * | |
3937 * TODO: remove the do_local_background fixup below. | |
3938 */ | |
3939 if (do_local_compose == 0 && do_local_background != 2) | |
3940 passes = png_set_interlace_handling(png_ptr); | |
3941 | |
3942 png_read_update_info(png_ptr, info_ptr); | |
3943 | |
3944 { | |
3945 png_uint_32 info_format = 0; | |
3946 | |
3947 if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0) | |
3948 info_format |= PNG_FORMAT_FLAG_COLOR; | |
3949 | |
3950 if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0) | |
3951 { | |
3952 /* do_local_compose removes this channel below. */ | |
3953 if (do_local_compose == 0) | |
3954 { | |
3955 /* do_local_background does the same if required. */ | |
3956 if (do_local_background != 2 || | |
3957 (format & PNG_FORMAT_FLAG_ALPHA) != 0) | |
3958 info_format |= PNG_FORMAT_FLAG_ALPHA; | |
3959 } | |
3960 } | |
3961 | |
3962 else if (do_local_compose != 0) /* internal error */ | |
3963 png_error(png_ptr, "png_image_read: alpha channel lost"); | |
3964 | |
3965 if (info_ptr->bit_depth == 16) | |
3966 info_format |= PNG_FORMAT_FLAG_LINEAR; | |
3967 | |
3968 # ifdef PNG_FORMAT_BGR_SUPPORTED | |
3969 if ((png_ptr->transformations & PNG_BGR) != 0) | |
3970 info_format |= PNG_FORMAT_FLAG_BGR; | |
3971 # endif | |
3972 | |
3973 # ifdef PNG_FORMAT_AFIRST_SUPPORTED | |
3974 if (do_local_background == 2) | |
3975 { | |
3976 if ((format & PNG_FORMAT_FLAG_AFIRST) != 0) | |
3977 info_format |= PNG_FORMAT_FLAG_AFIRST; | |
3978 } | |
3979 | |
3980 if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 || | |
3981 ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 && | |
3982 (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0)) | |
3983 { | |
3984 if (do_local_background == 2) | |
3985 png_error(png_ptr, "unexpected alpha swap transformation"); | |
3986 | |
3987 info_format |= PNG_FORMAT_FLAG_AFIRST; | |
3988 } | |
3989 # endif | |
3990 | |
3991 /* This is actually an internal error. */ | |
3992 if (info_format != format) | |
3993 png_error(png_ptr, "png_read_image: invalid transformations"); | |
3994 } | |
3995 | |
3996 /* Now read the rows. If do_local_compose is set then it is necessary to use | |
3997 * a local row buffer. The output will be GA, RGBA or BGRA and must be | |
3998 * converted to G, RGB or BGR as appropriate. The 'local_row' member of the | |
3999 * display acts as a flag. | |
4000 */ | |
4001 { | |
4002 png_voidp first_row = display->buffer; | |
4003 ptrdiff_t row_bytes = display->row_stride; | |
4004 | |
4005 if (linear != 0) | |
4006 row_bytes *= 2; | |
4007 | |
4008 /* The following expression is designed to work correctly whether it gives | |
4009 * a signed or an unsigned result. | |
4010 */ | |
4011 if (row_bytes < 0) | |
4012 { | |
4013 char *ptr = png_voidcast(char*, first_row); | |
4014 ptr += (image->height-1) * (-row_bytes); | |
4015 first_row = png_voidcast(png_voidp, ptr); | |
4016 } | |
4017 | |
4018 display->first_row = first_row; | |
4019 display->row_bytes = row_bytes; | |
4020 } | |
4021 | |
4022 if (do_local_compose != 0) | |
4023 { | |
4024 int result; | |
4025 png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr)); | |
4026 | |
4027 display->local_row = row; | |
4028 result = png_safe_execute(image, png_image_read_composite, display); | |
4029 display->local_row = NULL; | |
4030 png_free(png_ptr, row); | |
4031 | |
4032 return result; | |
4033 } | |
4034 | |
4035 else if (do_local_background == 2) | |
4036 { | |
4037 int result; | |
4038 png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr)); | |
4039 | |
4040 display->local_row = row; | |
4041 result = png_safe_execute(image, png_image_read_background, display); | |
4042 display->local_row = NULL; | |
4043 png_free(png_ptr, row); | |
4044 | |
4045 return result; | |
4046 } | |
4047 | |
4048 else | |
4049 { | |
4050 png_alloc_size_t row_bytes = display->row_bytes; | |
4051 | |
4052 while (--passes >= 0) | |
4053 { | |
4054 png_uint_32 y = image->height; | |
4055 png_bytep row = png_voidcast(png_bytep, display->first_row); | |
4056 | |
4057 while (y-- > 0) | |
4058 { | |
4059 png_read_row(png_ptr, row, NULL); | |
4060 row += row_bytes; | |
4061 } | |
4062 } | |
4063 | |
4064 return 1; | |
4065 } | |
4066 } | |
4067 | |
4068 int PNGAPI | |
4069 png_image_finish_read(png_imagep image, png_const_colorp background, | |
4070 void *buffer, png_int_32 row_stride, void *colormap) | |
4071 { | |
4072 if (image != NULL && image->version == PNG_IMAGE_VERSION) | |
4073 { | |
4074 png_uint_32 check; | |
4075 | |
4076 if (row_stride == 0) | |
4077 row_stride = PNG_IMAGE_ROW_STRIDE(*image); | |
4078 | |
4079 if (row_stride < 0) | |
4080 check = -row_stride; | |
4081 | |
4082 else | |
4083 check = row_stride; | |
4084 | |
4085 if (image->opaque != NULL && buffer != NULL && | |
4086 check >= PNG_IMAGE_ROW_STRIDE(*image)) | |
4087 { | |
4088 if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 || | |
4089 (image->colormap_entries > 0 && colormap != NULL)) | |
4090 { | |
4091 int result; | |
4092 png_image_read_control display; | |
4093 | |
4094 memset(&display, 0, (sizeof display)); | |
4095 display.image = image; | |
4096 display.buffer = buffer; | |
4097 display.row_stride = row_stride; | |
4098 display.colormap = colormap; | |
4099 display.background = background; | |
4100 display.local_row = NULL; | |
4101 | |
4102 /* Choose the correct 'end' routine; for the color-map case all the | |
4103 * setup has already been done. | |
4104 */ | |
4105 if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0) | |
4106 result = | |
4107 png_safe_execute(image, png_image_read_colormap, &display) && | |
4108 png_safe_execute(image, png_image_read_colormapped, &display); | |
4109 | |
4110 else | |
4111 result = | |
4112 png_safe_execute(image, png_image_read_direct, &display); | |
4113 | |
4114 png_image_free(image); | |
4115 return result; | |
4116 } | |
4117 | |
4118 else | |
4119 return png_image_error(image, | |
4120 "png_image_finish_read[color-map]: no color-map"); | |
4121 } | |
4122 | |
4123 else | |
4124 return png_image_error(image, | |
4125 "png_image_finish_read: invalid argument"); | |
4126 } | |
4127 | |
4128 else if (image != NULL) | |
4129 return png_image_error(image, | |
4130 "png_image_finish_read: damaged PNG_IMAGE_VERSION"); | |
4131 | |
4132 return 0; | |
4133 } | |
4134 | |
4135 #endif /* SIMPLIFIED_READ */ | |
4136 #endif /* READ */ | |
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