source: trunk/src/3rdparty/libpng/pngwtran.c@ 890

Last change on this file since 890 was 846, checked in by Dmitry A. Kuminov, 14 years ago

trunk: Merged in qt 4.7.2 sources from branches/vendor/nokia/qt.
File size: 16.5 KB
Line 
1
2/* pngwtran.c - transforms the data in a row for PNG writers
3 *
4 * Last changed in libpng 1.4.0 [January 3, 2010]
5 * Copyright (c) 1998-2010 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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
14#define PNG_NO_PEDANTIC_WARNINGS
15#include "png.h"
16#ifdef PNG_WRITE_SUPPORTED
17#include "pngpriv.h"
18
19/* Transform the data according to the user's wishes. The order of
20 * transformations is significant.
21 */
22void /* PRIVATE */
23png_do_write_transformations(png_structp png_ptr)
24{
25 png_debug(1, "in png_do_write_transformations");
26
27 if (png_ptr == NULL)
28 return;
29
30#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
31 if (png_ptr->transformations & PNG_USER_TRANSFORM)
32 if (png_ptr->write_user_transform_fn != NULL)
33 (*(png_ptr->write_user_transform_fn)) /* User write transform function */
34 (png_ptr, /* png_ptr */
35 &(png_ptr->row_info), /* row_info: */
36 /* png_uint_32 width; width of row */
37 /* png_uint_32 rowbytes; number of bytes in row */
38 /* png_byte color_type; color type of pixels */
39 /* png_byte bit_depth; bit depth of samples */
40 /* png_byte channels; number of channels (1-4) */
41 /* png_byte pixel_depth; bits per pixel (depth*channels) */
42 png_ptr->row_buf + 1); /* start of pixel data for row */
43#endif
44#ifdef PNG_WRITE_FILLER_SUPPORTED
45 if (png_ptr->transformations & PNG_FILLER)
46 png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
47 png_ptr->flags);
48#endif
49#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
50 if (png_ptr->transformations & PNG_PACKSWAP)
51 png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
52#endif
53#ifdef PNG_WRITE_PACK_SUPPORTED
54 if (png_ptr->transformations & PNG_PACK)
55 png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
56 (png_uint_32)png_ptr->bit_depth);
57#endif
58#ifdef PNG_WRITE_SWAP_SUPPORTED
59 if (png_ptr->transformations & PNG_SWAP_BYTES)
60 png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
61#endif
62#ifdef PNG_WRITE_SHIFT_SUPPORTED
63 if (png_ptr->transformations & PNG_SHIFT)
64 png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
65 &(png_ptr->shift));
66#endif
67#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
68 if (png_ptr->transformations & PNG_SWAP_ALPHA)
69 png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
70#endif
71#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
72 if (png_ptr->transformations & PNG_INVERT_ALPHA)
73 png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
74#endif
75#ifdef PNG_WRITE_BGR_SUPPORTED
76 if (png_ptr->transformations & PNG_BGR)
77 png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
78#endif
79#ifdef PNG_WRITE_INVERT_SUPPORTED
80 if (png_ptr->transformations & PNG_INVERT_MONO)
81 png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
82#endif
83}
84
85#ifdef PNG_WRITE_PACK_SUPPORTED
86/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
87 * row_info bit depth should be 8 (one pixel per byte). The channels
88 * should be 1 (this only happens on grayscale and paletted images).
89 */
90void /* PRIVATE */
91png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
92{
93 png_debug(1, "in png_do_pack");
94
95 if (row_info->bit_depth == 8 &&
96 row_info->channels == 1)
97 {
98 switch ((int)bit_depth)
99 {
100 case 1:
101 {
102 png_bytep sp, dp;
103 int mask, v;
104 png_uint_32 i;
105 png_uint_32 row_width = row_info->width;
106
107 sp = row;
108 dp = row;
109 mask = 0x80;
110 v = 0;
111
112 for (i = 0; i < row_width; i++)
113 {
114 if (*sp != 0)
115 v |= mask;
116 sp++;
117 if (mask > 1)
118 mask >>= 1;
119 else
120 {
121 mask = 0x80;
122 *dp = (png_byte)v;
123 dp++;
124 v = 0;
125 }
126 }
127 if (mask != 0x80)
128 *dp = (png_byte)v;
129 break;
130 }
131 case 2:
132 {
133 png_bytep sp, dp;
134 int shift, v;
135 png_uint_32 i;
136 png_uint_32 row_width = row_info->width;
137
138 sp = row;
139 dp = row;
140 shift = 6;
141 v = 0;
142 for (i = 0; i < row_width; i++)
143 {
144 png_byte value;
145
146 value = (png_byte)(*sp & 0x03);
147 v |= (value << shift);
148 if (shift == 0)
149 {
150 shift = 6;
151 *dp = (png_byte)v;
152 dp++;
153 v = 0;
154 }
155 else
156 shift -= 2;
157 sp++;
158 }
159 if (shift != 6)
160 *dp = (png_byte)v;
161 break;
162 }
163 case 4:
164 {
165 png_bytep sp, dp;
166 int shift, v;
167 png_uint_32 i;
168 png_uint_32 row_width = row_info->width;
169
170 sp = row;
171 dp = row;
172 shift = 4;
173 v = 0;
174 for (i = 0; i < row_width; i++)
175 {
176 png_byte value;
177
178 value = (png_byte)(*sp & 0x0f);
179 v |= (value << shift);
180
181 if (shift == 0)
182 {
183 shift = 4;
184 *dp = (png_byte)v;
185 dp++;
186 v = 0;
187 }
188 else
189 shift -= 4;
190
191 sp++;
192 }
193 if (shift != 4)
194 *dp = (png_byte)v;
195 break;
196 }
197 }
198 row_info->bit_depth = (png_byte)bit_depth;
199 row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
200 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
201 row_info->width);
202 }
203}
204#endif
205
206#ifdef PNG_WRITE_SHIFT_SUPPORTED
207/* Shift pixel values to take advantage of whole range. Pass the
208 * true number of bits in bit_depth. The row should be packed
209 * according to row_info->bit_depth. Thus, if you had a row of
210 * bit depth 4, but the pixels only had values from 0 to 7, you
211 * would pass 3 as bit_depth, and this routine would translate the
212 * data to 0 to 15.
213 */
214void /* PRIVATE */
215png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
216{
217 png_debug(1, "in png_do_shift");
218
219 if (
220 row_info->color_type != PNG_COLOR_TYPE_PALETTE)
221 {
222 int shift_start[4], shift_dec[4];
223 int channels = 0;
224
225 if (row_info->color_type & PNG_COLOR_MASK_COLOR)
226 {
227 shift_start[channels] = row_info->bit_depth - bit_depth->red;
228 shift_dec[channels] = bit_depth->red;
229 channels++;
230 shift_start[channels] = row_info->bit_depth - bit_depth->green;
231 shift_dec[channels] = bit_depth->green;
232 channels++;
233 shift_start[channels] = row_info->bit_depth - bit_depth->blue;
234 shift_dec[channels] = bit_depth->blue;
235 channels++;
236 }
237 else
238 {
239 shift_start[channels] = row_info->bit_depth - bit_depth->gray;
240 shift_dec[channels] = bit_depth->gray;
241 channels++;
242 }
243 if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
244 {
245 shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
246 shift_dec[channels] = bit_depth->alpha;
247 channels++;
248 }
249
250 /* With low row depths, could only be grayscale, so one channel */
251 if (row_info->bit_depth < 8)
252 {
253 png_bytep bp = row;
254 png_uint_32 i;
255 png_byte mask;
256 png_uint_32 row_bytes = row_info->rowbytes;
257
258 if (bit_depth->gray == 1 && row_info->bit_depth == 2)
259 mask = 0x55;
260 else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
261 mask = 0x11;
262 else
263 mask = 0xff;
264
265 for (i = 0; i < row_bytes; i++, bp++)
266 {
267 png_uint_16 v;
268 int j;
269
270 v = *bp;
271 *bp = 0;
272 for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
273 {
274 if (j > 0)
275 *bp |= (png_byte)((v << j) & 0xff);
276 else
277 *bp |= (png_byte)((v >> (-j)) & mask);
278 }
279 }
280 }
281 else if (row_info->bit_depth == 8)
282 {
283 png_bytep bp = row;
284 png_uint_32 i;
285 png_uint_32 istop = channels * row_info->width;
286
287 for (i = 0; i < istop; i++, bp++)
288 {
289
290 png_uint_16 v;
291 int j;
292 int c = (int)(i%channels);
293
294 v = *bp;
295 *bp = 0;
296 for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
297 {
298 if (j > 0)
299 *bp |= (png_byte)((v << j) & 0xff);
300 else
301 *bp |= (png_byte)((v >> (-j)) & 0xff);
302 }
303 }
304 }
305 else
306 {
307 png_bytep bp;
308 png_uint_32 i;
309 png_uint_32 istop = channels * row_info->width;
310
311 for (bp = row, i = 0; i < istop; i++)
312 {
313 int c = (int)(i%channels);
314 png_uint_16 value, v;
315 int j;
316
317 v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
318 value = 0;
319 for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
320 {
321 if (j > 0)
322 value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
323 else
324 value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
325 }
326 *bp++ = (png_byte)(value >> 8);
327 *bp++ = (png_byte)(value & 0xff);
328 }
329 }
330 }
331}
332#endif
333
334#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
335void /* PRIVATE */
336png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
337{
338 png_debug(1, "in png_do_write_swap_alpha");
339
340 {
341 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
342 {
343 /* This converts from ARGB to RGBA */
344 if (row_info->bit_depth == 8)
345 {
346 png_bytep sp, dp;
347 png_uint_32 i;
348 png_uint_32 row_width = row_info->width;
349 for (i = 0, sp = dp = row; i < row_width; i++)
350 {
351 png_byte save = *(sp++);
352 *(dp++) = *(sp++);
353 *(dp++) = *(sp++);
354 *(dp++) = *(sp++);
355 *(dp++) = save;
356 }
357 }
358 /* This converts from AARRGGBB to RRGGBBAA */
359 else
360 {
361 png_bytep sp, dp;
362 png_uint_32 i;
363 png_uint_32 row_width = row_info->width;
364
365 for (i = 0, sp = dp = row; i < row_width; i++)
366 {
367 png_byte save[2];
368 save[0] = *(sp++);
369 save[1] = *(sp++);
370 *(dp++) = *(sp++);
371 *(dp++) = *(sp++);
372 *(dp++) = *(sp++);
373 *(dp++) = *(sp++);
374 *(dp++) = *(sp++);
375 *(dp++) = *(sp++);
376 *(dp++) = save[0];
377 *(dp++) = save[1];
378 }
379 }
380 }
381 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
382 {
383 /* This converts from AG to GA */
384 if (row_info->bit_depth == 8)
385 {
386 png_bytep sp, dp;
387 png_uint_32 i;
388 png_uint_32 row_width = row_info->width;
389
390 for (i = 0, sp = dp = row; i < row_width; i++)
391 {
392 png_byte save = *(sp++);
393 *(dp++) = *(sp++);
394 *(dp++) = save;
395 }
396 }
397 /* This converts from AAGG to GGAA */
398 else
399 {
400 png_bytep sp, dp;
401 png_uint_32 i;
402 png_uint_32 row_width = row_info->width;
403
404 for (i = 0, sp = dp = row; i < row_width; i++)
405 {
406 png_byte save[2];
407 save[0] = *(sp++);
408 save[1] = *(sp++);
409 *(dp++) = *(sp++);
410 *(dp++) = *(sp++);
411 *(dp++) = save[0];
412 *(dp++) = save[1];
413 }
414 }
415 }
416 }
417}
418#endif
419
420#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
421void /* PRIVATE */
422png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
423{
424 png_debug(1, "in png_do_write_invert_alpha");
425
426 {
427 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
428 {
429 /* This inverts the alpha channel in RGBA */
430 if (row_info->bit_depth == 8)
431 {
432 png_bytep sp, dp;
433 png_uint_32 i;
434 png_uint_32 row_width = row_info->width;
435 for (i = 0, sp = dp = row; i < row_width; i++)
436 {
437 /* Does nothing
438 *(dp++) = *(sp++);
439 *(dp++) = *(sp++);
440 *(dp++) = *(sp++);
441 */
442 sp+=3; dp = sp;
443 *(dp++) = (png_byte)(255 - *(sp++));
444 }
445 }
446 /* This inverts the alpha channel in RRGGBBAA */
447 else
448 {
449 png_bytep sp, dp;
450 png_uint_32 i;
451 png_uint_32 row_width = row_info->width;
452
453 for (i = 0, sp = dp = row; i < row_width; i++)
454 {
455 /* Does nothing
456 *(dp++) = *(sp++);
457 *(dp++) = *(sp++);
458 *(dp++) = *(sp++);
459 *(dp++) = *(sp++);
460 *(dp++) = *(sp++);
461 *(dp++) = *(sp++);
462 */
463 sp+=6; dp = sp;
464 *(dp++) = (png_byte)(255 - *(sp++));
465 *(dp++) = (png_byte)(255 - *(sp++));
466 }
467 }
468 }
469 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
470 {
471 /* This inverts the alpha channel in GA */
472 if (row_info->bit_depth == 8)
473 {
474 png_bytep sp, dp;
475 png_uint_32 i;
476 png_uint_32 row_width = row_info->width;
477
478 for (i = 0, sp = dp = row; i < row_width; i++)
479 {
480 *(dp++) = *(sp++);
481 *(dp++) = (png_byte)(255 - *(sp++));
482 }
483 }
484 /* This inverts the alpha channel in GGAA */
485 else
486 {
487 png_bytep sp, dp;
488 png_uint_32 i;
489 png_uint_32 row_width = row_info->width;
490
491 for (i = 0, sp = dp = row; i < row_width; i++)
492 {
493 /* Does nothing
494 *(dp++) = *(sp++);
495 *(dp++) = *(sp++);
496 */
497 sp+=2; dp = sp;
498 *(dp++) = (png_byte)(255 - *(sp++));
499 *(dp++) = (png_byte)(255 - *(sp++));
500 }
501 }
502 }
503 }
504}
505#endif
506
507#ifdef PNG_MNG_FEATURES_SUPPORTED
508/* Undoes intrapixel differencing */
509void /* PRIVATE */
510png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
511{
512 png_debug(1, "in png_do_write_intrapixel");
513
514 if (
515 (row_info->color_type & PNG_COLOR_MASK_COLOR))
516 {
517 int bytes_per_pixel;
518 png_uint_32 row_width = row_info->width;
519 if (row_info->bit_depth == 8)
520 {
521 png_bytep rp;
522 png_uint_32 i;
523
524 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
525 bytes_per_pixel = 3;
526 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
527 bytes_per_pixel = 4;
528 else
529 return;
530
531 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
532 {
533 *(rp) = (png_byte)((*rp - *(rp+1))&0xff);
534 *(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff);
535 }
536 }
537 else if (row_info->bit_depth == 16)
538 {
539 png_bytep rp;
540 png_uint_32 i;
541
542 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
543 bytes_per_pixel = 6;
544 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
545 bytes_per_pixel = 8;
546 else
547 return;
548
549 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
550 {
551 png_uint_32 s0 = (*(rp ) << 8) | *(rp+1);
552 png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3);
553 png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5);
554 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
555 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
556 *(rp ) = (png_byte)((red >> 8) & 0xff);
557 *(rp+1) = (png_byte)(red & 0xff);
558 *(rp+4) = (png_byte)((blue >> 8) & 0xff);
559 *(rp+5) = (png_byte)(blue & 0xff);
560 }
561 }
562 }
563}
564#endif /* PNG_MNG_FEATURES_SUPPORTED */
565#endif /* PNG_WRITE_SUPPORTED */
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