pngwtran.c@ 102315

最後變更在這個檔案從102315是 96425,由 vboxsync 提交於 2 年前
src/libs: Switch to libpng-1.6.37, bugref:8515 [re-export]
屬性 svn:eol-style 設為 `native`
檔案大小: 15.0 KB

行
1
2	/* pngwtran.c - transforms the data in a row for PNG writers
3	*
4	* Copyright (c) 2018 Cosmin Truta
5	* Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
6	* Copyright (c) 1996-1997 Andreas Dilger
7	* 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	#include "pngpriv.h"
15
16	#ifdef PNG_WRITE_SUPPORTED
17	#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
18
19	#ifdef PNG_WRITE_PACK_SUPPORTED
20	/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
21	* row_info bit depth should be 8 (one pixel per byte). The channels
22	* should be 1 (this only happens on grayscale and paletted images).
23	*/
24	static void
25	png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
26	{
27	png_debug(1, "in png_do_pack");
28
29	if (row_info->bit_depth == 8 &&
30	row_info->channels == 1)
31	{
32	switch ((int)bit_depth)
33	{
34	case 1:
35	{
36	png_bytep sp, dp;
37	int mask, v;
38	png_uint_32 i;
39	png_uint_32 row_width = row_info->width;
40
41	sp = row;
42	dp = row;
43	mask = 0x80;
44	v = 0;
45
46	for (i = 0; i < row_width; i++)
47	{
48	if (*sp != 0)
49	v \|= mask;
50
51	sp++;
52
53	if (mask > 1)
54	mask >>= 1;
55
56	else
57	{
58	mask = 0x80;
59	*dp = (png_byte)v;
60	dp++;
61	v = 0;
62	}
63	}
64
65	if (mask != 0x80)
66	*dp = (png_byte)v;
67
68	break;
69	}
70
71	case 2:
72	{
73	png_bytep sp, dp;
74	unsigned int shift;
75	int v;
76	png_uint_32 i;
77	png_uint_32 row_width = row_info->width;
78
79	sp = row;
80	dp = row;
81	shift = 6;
82	v = 0;
83
84	for (i = 0; i < row_width; i++)
85	{
86	png_byte value;
87
88	value = (png_byte)(*sp & 0x03);
89	v \|= (value << shift);
90
91	if (shift == 0)
92	{
93	shift = 6;
94	*dp = (png_byte)v;
95	dp++;
96	v = 0;
97	}
98
99	else
100	shift -= 2;
101
102	sp++;
103	}
104
105	if (shift != 6)
106	*dp = (png_byte)v;
107
108	break;
109	}
110
111	case 4:
112	{
113	png_bytep sp, dp;
114	unsigned int shift;
115	int v;
116	png_uint_32 i;
117	png_uint_32 row_width = row_info->width;
118
119	sp = row;
120	dp = row;
121	shift = 4;
122	v = 0;
123
124	for (i = 0; i < row_width; i++)
125	{
126	png_byte value;
127
128	value = (png_byte)(*sp & 0x0f);
129	v \|= (value << shift);
130
131	if (shift == 0)
132	{
133	shift = 4;
134	*dp = (png_byte)v;
135	dp++;
136	v = 0;
137	}
138
139	else
140	shift -= 4;
141
142	sp++;
143	}
144
145	if (shift != 4)
146	*dp = (png_byte)v;
147
148	break;
149	}
150
151	default:
152	break;
153	}
154
155	row_info->bit_depth = (png_byte)bit_depth;
156	row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
157	row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
158	row_info->width);
159	}
160	}
161	#endif
162
163	#ifdef PNG_WRITE_SHIFT_SUPPORTED
164	/* Shift pixel values to take advantage of whole range. Pass the
165	* true number of bits in bit_depth. The row should be packed
166	* according to row_info->bit_depth. Thus, if you had a row of
167	* bit depth 4, but the pixels only had values from 0 to 7, you
168	* would pass 3 as bit_depth, and this routine would translate the
169	* data to 0 to 15.
170	*/
171	static void
172	png_do_shift(png_row_infop row_info, png_bytep row,
173	png_const_color_8p bit_depth)
174	{
175	png_debug(1, "in png_do_shift");
176
177	if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
178	{
179	int shift_start[4], shift_dec[4];
180	unsigned int channels = 0;
181
182	if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
183	{
184	shift_start[channels] = row_info->bit_depth - bit_depth->red;
185	shift_dec[channels] = bit_depth->red;
186	channels++;
187
188	shift_start[channels] = row_info->bit_depth - bit_depth->green;
189	shift_dec[channels] = bit_depth->green;
190	channels++;
191
192	shift_start[channels] = row_info->bit_depth - bit_depth->blue;
193	shift_dec[channels] = bit_depth->blue;
194	channels++;
195	}
196
197	else
198	{
199	shift_start[channels] = row_info->bit_depth - bit_depth->gray;
200	shift_dec[channels] = bit_depth->gray;
201	channels++;
202	}
203
204	if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
205	{
206	shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
207	shift_dec[channels] = bit_depth->alpha;
208	channels++;
209	}
210
211	/* With low row depths, could only be grayscale, so one channel */
212	if (row_info->bit_depth < 8)
213	{
214	png_bytep bp = row;
215	size_t i;
216	unsigned int mask;
217	size_t row_bytes = row_info->rowbytes;
218
219	if (bit_depth->gray == 1 && row_info->bit_depth == 2)
220	mask = 0x55;
221
222	else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
223	mask = 0x11;
224
225	else
226	mask = 0xff;
227
228	for (i = 0; i < row_bytes; i++, bp++)
229	{
230	int j;
231	unsigned int v, out;
232
233	v = *bp;
234	out = 0;
235
236	for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
237	{
238	if (j > 0)
239	out \|= v << j;
240
241	else
242	out \|= (v >> (-j)) & mask;
243	}
244
245	*bp = (png_byte)(out & 0xff);
246	}
247	}
248
249	else if (row_info->bit_depth == 8)
250	{
251	png_bytep bp = row;
252	png_uint_32 i;
253	png_uint_32 istop = channels * row_info->width;
254
255	for (i = 0; i < istop; i++, bp++)
256	{
257	unsigned int c = i%channels;
258	int j;
259	unsigned int v, out;
260
261	v = *bp;
262	out = 0;
263
264	for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
265	{
266	if (j > 0)
267	out \|= v << j;
268
269	else
270	out \|= v >> (-j);
271	}
272
273	*bp = (png_byte)(out & 0xff);
274	}
275	}
276
277	else
278	{
279	png_bytep bp;
280	png_uint_32 i;
281	png_uint_32 istop = channels * row_info->width;
282
283	for (bp = row, i = 0; i < istop; i++)
284	{
285	unsigned int c = i%channels;
286	int j;
287	unsigned int value, v;
288
289	v = png_get_uint_16(bp);
290	value = 0;
291
292	for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
293	{
294	if (j > 0)
295	value \|= v << j;
296
297	else
298	value \|= v >> (-j);
299	}
300	*bp++ = (png_byte)((value >> 8) & 0xff);
301	*bp++ = (png_byte)(value & 0xff);
302	}
303	}
304	}
305	}
306	#endif
307
308	#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
309	static void
310	png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
311	{
312	png_debug(1, "in png_do_write_swap_alpha");
313
314	{
315	if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
316	{
317	if (row_info->bit_depth == 8)
318	{
319	/* This converts from ARGB to RGBA */
320	png_bytep sp, dp;
321	png_uint_32 i;
322	png_uint_32 row_width = row_info->width;
323
324	for (i = 0, sp = dp = row; i < row_width; i++)
325	{
326	png_byte save = *(sp++);
327	(dp++) = (sp++);
328	(dp++) = (sp++);
329	(dp++) = (sp++);
330	*(dp++) = save;
331	}
332	}
333
334	#ifdef PNG_WRITE_16BIT_SUPPORTED
335	else
336	{
337	/* This converts from AARRGGBB to RRGGBBAA */
338	png_bytep sp, dp;
339	png_uint_32 i;
340	png_uint_32 row_width = row_info->width;
341
342	for (i = 0, sp = dp = row; i < row_width; i++)
343	{
344	png_byte save[2];
345	save[0] = *(sp++);
346	save[1] = *(sp++);
347	(dp++) = (sp++);
348	(dp++) = (sp++);
349	(dp++) = (sp++);
350	(dp++) = (sp++);
351	(dp++) = (sp++);
352	(dp++) = (sp++);
353	*(dp++) = save[0];
354	*(dp++) = save[1];
355	}
356	}
357	#endif /* WRITE_16BIT */
358	}
359
360	else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
361	{
362	if (row_info->bit_depth == 8)
363	{
364	/* This converts from AG to GA */
365	png_bytep sp, dp;
366	png_uint_32 i;
367	png_uint_32 row_width = row_info->width;
368
369	for (i = 0, sp = dp = row; i < row_width; i++)
370	{
371	png_byte save = *(sp++);
372	(dp++) = (sp++);
373	*(dp++) = save;
374	}
375	}
376
377	#ifdef PNG_WRITE_16BIT_SUPPORTED
378	else
379	{
380	/* This converts from AAGG to GGAA */
381	png_bytep sp, dp;
382	png_uint_32 i;
383	png_uint_32 row_width = row_info->width;
384
385	for (i = 0, sp = dp = row; i < row_width; i++)
386	{
387	png_byte save[2];
388	save[0] = *(sp++);
389	save[1] = *(sp++);
390	(dp++) = (sp++);
391	(dp++) = (sp++);
392	*(dp++) = save[0];
393	*(dp++) = save[1];
394	}
395	}
396	#endif /* WRITE_16BIT */
397	}
398	}
399	}
400	#endif
401
402	#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
403	static void
404	png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
405	{
406	png_debug(1, "in png_do_write_invert_alpha");
407
408	{
409	if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
410	{
411	if (row_info->bit_depth == 8)
412	{
413	/* This inverts the alpha channel in RGBA */
414	png_bytep sp, dp;
415	png_uint_32 i;
416	png_uint_32 row_width = row_info->width;
417
418	for (i = 0, sp = dp = row; i < row_width; i++)
419	{
420	/* Does nothing
421	(dp++) = (sp++);
422	(dp++) = (sp++);
423	(dp++) = (sp++);
424	*/
425	sp+=3; dp = sp;
426	dp = (png_byte)(255 - (sp++));
427	}
428	}
429
430	#ifdef PNG_WRITE_16BIT_SUPPORTED
431	else
432	{
433	/* This inverts the alpha channel in RRGGBBAA */
434	png_bytep sp, dp;
435	png_uint_32 i;
436	png_uint_32 row_width = row_info->width;
437
438	for (i = 0, sp = dp = row; i < row_width; i++)
439	{
440	/* Does nothing
441	(dp++) = (sp++);
442	(dp++) = (sp++);
443	(dp++) = (sp++);
444	(dp++) = (sp++);
445	(dp++) = (sp++);
446	(dp++) = (sp++);
447	*/
448	sp+=6; dp = sp;
449	(dp++) = (png_byte)(255 - (sp++));
450	dp = (png_byte)(255 - (sp++));
451	}
452	}
453	#endif /* WRITE_16BIT */
454	}
455
456	else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
457	{
458	if (row_info->bit_depth == 8)
459	{
460	/* This inverts the alpha channel in GA */
461	png_bytep sp, dp;
462	png_uint_32 i;
463	png_uint_32 row_width = row_info->width;
464
465	for (i = 0, sp = dp = row; i < row_width; i++)
466	{
467	(dp++) = (sp++);
468	(dp++) = (png_byte)(255 - (sp++));
469	}
470	}
471
472	#ifdef PNG_WRITE_16BIT_SUPPORTED
473	else
474	{
475	/* This inverts the alpha channel in GGAA */
476	png_bytep sp, dp;
477	png_uint_32 i;
478	png_uint_32 row_width = row_info->width;
479
480	for (i = 0, sp = dp = row; i < row_width; i++)
481	{
482	/* Does nothing
483	(dp++) = (sp++);
484	(dp++) = (sp++);
485	*/
486	sp+=2; dp = sp;
487	(dp++) = (png_byte)(255 - (sp++));
488	dp = (png_byte)(255 - (sp++));
489	}
490	}
491	#endif /* WRITE_16BIT */
492	}
493	}
494	}
495	#endif
496
497	/* Transform the data according to the user's wishes. The order of
498	* transformations is significant.
499	*/
500	void /* PRIVATE */
501	png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
502	{
503	png_debug(1, "in png_do_write_transformations");
504
505	if (png_ptr == NULL)
506	return;
507
508	#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
509	if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
510	if (png_ptr->write_user_transform_fn != NULL)
511	((png_ptr->write_user_transform_fn)) / User write transform
512	function */
513	(png_ptr, /* png_ptr */
514	row_info, /* row_info: */
515	/* png_uint_32 width; width of row */
516	/* size_t rowbytes; number of bytes in row */
517	/* png_byte color_type; color type of pixels */
518	/* png_byte bit_depth; bit depth of samples */
519	/* png_byte channels; number of channels (1-4) */
520	/* png_byte pixel_depth; bits per pixel (depthchannels) /
521	png_ptr->row_buf + 1); /* start of pixel data for row */
522	#endif
523
524	#ifdef PNG_WRITE_FILLER_SUPPORTED
525	if ((png_ptr->transformations & PNG_FILLER) != 0)
526	png_do_strip_channel(row_info, png_ptr->row_buf + 1,
527	!(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
528	#endif
529
530	#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
531	if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
532	png_do_packswap(row_info, png_ptr->row_buf + 1);
533	#endif
534
535	#ifdef PNG_WRITE_PACK_SUPPORTED
536	if ((png_ptr->transformations & PNG_PACK) != 0)
537	png_do_pack(row_info, png_ptr->row_buf + 1,
538	(png_uint_32)png_ptr->bit_depth);
539	#endif
540
541	#ifdef PNG_WRITE_SWAP_SUPPORTED
542	# ifdef PNG_16BIT_SUPPORTED
543	if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
544	png_do_swap(row_info, png_ptr->row_buf + 1);
545	# endif
546	#endif
547
548	#ifdef PNG_WRITE_SHIFT_SUPPORTED
549	if ((png_ptr->transformations & PNG_SHIFT) != 0)
550	png_do_shift(row_info, png_ptr->row_buf + 1,
551	&(png_ptr->shift));
552	#endif
553
554	#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
555	if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
556	png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
557	#endif
558
559	#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
560	if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
561	png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
562	#endif
563
564	#ifdef PNG_WRITE_BGR_SUPPORTED
565	if ((png_ptr->transformations & PNG_BGR) != 0)
566	png_do_bgr(row_info, png_ptr->row_buf + 1);
567	#endif
568
569	#ifdef PNG_WRITE_INVERT_SUPPORTED
570	if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
571	png_do_invert(row_info, png_ptr->row_buf + 1);
572	#endif
573	}
574	#endif /* WRITE_TRANSFORMS */
575	#endif /* WRITE */

注意: 瀏覽 TracBrowser 來幫助您使用儲存庫瀏覽器

source: vbox/trunk/src/libs/libpng-1.6.37/pngwtran.c@ 102315

以其他格式下載: