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source: vbox/trunk/src/libs/libpng-1.2.8/pngtrans.c@ 50079

Last change on this file since 50079 was 6393, checked in by vboxsync, 17 years ago

export libpng and zlib so Windows and OS/2 builds cleanly.
  • Property svn:eol-style set to native
File size: 19.9 KB
Line 
1
2/* pngtrans.c - transforms the data in a row (used by both readers and writers)
3 *
4 * libpng 1.2.8 - December 3, 2004
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2004 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 */
10
11#define PNG_INTERNAL
12#include "png.h"
13
14#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
15/* turn on BGR-to-RGB mapping */
16void PNGAPI
17png_set_bgr(png_structp png_ptr)
18{
19 png_debug(1, "in png_set_bgr\n");
20 png_ptr->transformations |= PNG_BGR;
21}
22#endif
23
24#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
25/* turn on 16 bit byte swapping */
26void PNGAPI
27png_set_swap(png_structp png_ptr)
28{
29 png_debug(1, "in png_set_swap\n");
30 if (png_ptr->bit_depth == 16)
31 png_ptr->transformations |= PNG_SWAP_BYTES;
32}
33#endif
34
35#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
36/* turn on pixel packing */
37void PNGAPI
38png_set_packing(png_structp png_ptr)
39{
40 png_debug(1, "in png_set_packing\n");
41 if (png_ptr->bit_depth < 8)
42 {
43 png_ptr->transformations |= PNG_PACK;
44 png_ptr->usr_bit_depth = 8;
45 }
46}
47#endif
48
49#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
50/* turn on packed pixel swapping */
51void PNGAPI
52png_set_packswap(png_structp png_ptr)
53{
54 png_debug(1, "in png_set_packswap\n");
55 if (png_ptr->bit_depth < 8)
56 png_ptr->transformations |= PNG_PACKSWAP;
57}
58#endif
59
60#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
61void PNGAPI
62png_set_shift(png_structp png_ptr, png_color_8p true_bits)
63{
64 png_debug(1, "in png_set_shift\n");
65 png_ptr->transformations |= PNG_SHIFT;
66 png_ptr->shift = *true_bits;
67}
68#endif
69
70#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
71 defined(PNG_WRITE_INTERLACING_SUPPORTED)
72int PNGAPI
73png_set_interlace_handling(png_structp png_ptr)
74{
75 png_debug(1, "in png_set_interlace handling\n");
76 if (png_ptr->interlaced)
77 {
78 png_ptr->transformations |= PNG_INTERLACE;
79 return (7);
80 }
81
82 return (1);
83}
84#endif
85
86#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
87/* Add a filler byte on read, or remove a filler or alpha byte on write.
88 * The filler type has changed in v0.95 to allow future 2-byte fillers
89 * for 48-bit input data, as well as to avoid problems with some compilers
90 * that don't like bytes as parameters.
91 */
92void PNGAPI
93png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
94{
95 png_debug(1, "in png_set_filler\n");
96 png_ptr->transformations |= PNG_FILLER;
97 png_ptr->filler = (png_byte)filler;
98 if (filler_loc == PNG_FILLER_AFTER)
99 png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
100 else
101 png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
102
103 /* This should probably go in the "do_read_filler" routine.
104 * I attempted to do that in libpng-1.0.1a but that caused problems
105 * so I restored it in libpng-1.0.2a
106 */
107
108 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
109 {
110 png_ptr->usr_channels = 4;
111 }
112
113 /* Also I added this in libpng-1.0.2a (what happens when we expand
114 * a less-than-8-bit grayscale to GA? */
115
116 if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth >= 8)
117 {
118 png_ptr->usr_channels = 2;
119 }
120}
121
122#if !defined(PNG_1_0_X)
123/* Added to libpng-1.2.7 */
124void PNGAPI
125png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
126{
127 png_debug(1, "in png_set_add_alpha\n");
128 png_set_filler(png_ptr, filler, filler_loc);
129 png_ptr->transformations |= PNG_ADD_ALPHA;
130}
131#endif
132
133#endif
134
135#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
136 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
137void PNGAPI
138png_set_swap_alpha(png_structp png_ptr)
139{
140 png_debug(1, "in png_set_swap_alpha\n");
141 png_ptr->transformations |= PNG_SWAP_ALPHA;
142}
143#endif
144
145#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
146 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
147void PNGAPI
148png_set_invert_alpha(png_structp png_ptr)
149{
150 png_debug(1, "in png_set_invert_alpha\n");
151 png_ptr->transformations |= PNG_INVERT_ALPHA;
152}
153#endif
154
155#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
156void PNGAPI
157png_set_invert_mono(png_structp png_ptr)
158{
159 png_debug(1, "in png_set_invert_mono\n");
160 png_ptr->transformations |= PNG_INVERT_MONO;
161}
162
163/* invert monochrome grayscale data */
164void /* PRIVATE */
165png_do_invert(png_row_infop row_info, png_bytep row)
166{
167 png_debug(1, "in png_do_invert\n");
168 /* This test removed from libpng version 1.0.13 and 1.2.0:
169 * if (row_info->bit_depth == 1 &&
170 */
171#if defined(PNG_USELESS_TESTS_SUPPORTED)
172 if (row == NULL || row_info == NULL)
173 return;
174#endif
175 if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
176 {
177 png_bytep rp = row;
178 png_uint_32 i;
179 png_uint_32 istop = row_info->rowbytes;
180
181 for (i = 0; i < istop; i++)
182 {
183 *rp = (png_byte)(~(*rp));
184 rp++;
185 }
186 }
187 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
188 row_info->bit_depth == 8)
189 {
190 png_bytep rp = row;
191 png_uint_32 i;
192 png_uint_32 istop = row_info->rowbytes;
193
194 for (i = 0; i < istop; i+=2)
195 {
196 *rp = (png_byte)(~(*rp));
197 rp+=2;
198 }
199 }
200 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
201 row_info->bit_depth == 16)
202 {
203 png_bytep rp = row;
204 png_uint_32 i;
205 png_uint_32 istop = row_info->rowbytes;
206
207 for (i = 0; i < istop; i+=4)
208 {
209 *rp = (png_byte)(~(*rp));
210 *(rp+1) = (png_byte)(~(*(rp+1)));
211 rp+=4;
212 }
213 }
214}
215#endif
216
217#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
218/* swaps byte order on 16 bit depth images */
219void /* PRIVATE */
220png_do_swap(png_row_infop row_info, png_bytep row)
221{
222 png_debug(1, "in png_do_swap\n");
223 if (
224#if defined(PNG_USELESS_TESTS_SUPPORTED)
225 row != NULL && row_info != NULL &&
226#endif
227 row_info->bit_depth == 16)
228 {
229 png_bytep rp = row;
230 png_uint_32 i;
231 png_uint_32 istop= row_info->width * row_info->channels;
232
233 for (i = 0; i < istop; i++, rp += 2)
234 {
235 png_byte t = *rp;
236 *rp = *(rp + 1);
237 *(rp + 1) = t;
238 }
239 }
240}
241#endif
242
243#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
244static png_byte onebppswaptable[256] = {
245 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
246 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
247 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
248 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
249 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
250 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
251 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
252 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
253 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
254 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
255 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
256 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
257 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
258 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
259 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
260 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
261 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
262 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
263 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
264 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
265 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
266 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
267 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
268 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
269 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
270 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
271 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
272 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
273 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
274 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
275 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
276 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
277};
278
279static png_byte twobppswaptable[256] = {
280 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
281 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
282 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
283 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
284 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
285 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
286 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
287 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
288 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
289 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
290 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
291 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
292 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
293 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
294 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
295 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
296 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
297 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
298 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
299 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
300 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
301 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
302 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
303 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
304 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
305 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
306 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
307 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
308 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
309 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
310 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
311 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
312};
313
314static png_byte fourbppswaptable[256] = {
315 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
316 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
317 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
318 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
319 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
320 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
321 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
322 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
323 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
324 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
325 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
326 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
327 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
328 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
329 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
330 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
331 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
332 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
333 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
334 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
335 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
336 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
337 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
338 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
339 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
340 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
341 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
342 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
343 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
344 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
345 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
346 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
347};
348
349/* swaps pixel packing order within bytes */
350void /* PRIVATE */
351png_do_packswap(png_row_infop row_info, png_bytep row)
352{
353 png_debug(1, "in png_do_packswap\n");
354 if (
355#if defined(PNG_USELESS_TESTS_SUPPORTED)
356 row != NULL && row_info != NULL &&
357#endif
358 row_info->bit_depth < 8)
359 {
360 png_bytep rp, end, table;
361
362 end = row + row_info->rowbytes;
363
364 if (row_info->bit_depth == 1)
365 table = onebppswaptable;
366 else if (row_info->bit_depth == 2)
367 table = twobppswaptable;
368 else if (row_info->bit_depth == 4)
369 table = fourbppswaptable;
370 else
371 return;
372
373 for (rp = row; rp < end; rp++)
374 *rp = table[*rp];
375 }
376}
377#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
378
379#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
380 defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
381/* remove filler or alpha byte(s) */
382void /* PRIVATE */
383png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
384{
385 png_debug(1, "in png_do_strip_filler\n");
386#if defined(PNG_USELESS_TESTS_SUPPORTED)
387 if (row != NULL && row_info != NULL)
388#endif
389 {
390 png_bytep sp=row;
391 png_bytep dp=row;
392 png_uint_32 row_width=row_info->width;
393 png_uint_32 i;
394
395 if ((row_info->color_type == PNG_COLOR_TYPE_RGB ||
396 (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
397 (flags & PNG_FLAG_STRIP_ALPHA))) &&
398 row_info->channels == 4)
399 {
400 if (row_info->bit_depth == 8)
401 {
402 /* This converts from RGBX or RGBA to RGB */
403 if (flags & PNG_FLAG_FILLER_AFTER)
404 {
405 dp+=3; sp+=4;
406 for (i = 1; i < row_width; i++)
407 {
408 *dp++ = *sp++;
409 *dp++ = *sp++;
410 *dp++ = *sp++;
411 sp++;
412 }
413 }
414 /* This converts from XRGB or ARGB to RGB */
415 else
416 {
417 for (i = 0; i < row_width; i++)
418 {
419 sp++;
420 *dp++ = *sp++;
421 *dp++ = *sp++;
422 *dp++ = *sp++;
423 }
424 }
425 row_info->pixel_depth = 24;
426 row_info->rowbytes = row_width * 3;
427 }
428 else /* if (row_info->bit_depth == 16) */
429 {
430 if (flags & PNG_FLAG_FILLER_AFTER)
431 {
432 /* This converts from RRGGBBXX or RRGGBBAA to RRGGBB */
433 sp += 8; dp += 6;
434 for (i = 1; i < row_width; i++)
435 {
436 /* This could be (although png_memcpy is probably slower):
437 png_memcpy(dp, sp, 6);
438 sp += 8;
439 dp += 6;
440 */
441
442 *dp++ = *sp++;
443 *dp++ = *sp++;
444 *dp++ = *sp++;
445 *dp++ = *sp++;
446 *dp++ = *sp++;
447 *dp++ = *sp++;
448 sp += 2;
449 }
450 }
451 else
452 {
453 /* This converts from XXRRGGBB or AARRGGBB to RRGGBB */
454 for (i = 0; i < row_width; i++)
455 {
456 /* This could be (although png_memcpy is probably slower):
457 png_memcpy(dp, sp, 6);
458 sp += 8;
459 dp += 6;
460 */
461
462 sp+=2;
463 *dp++ = *sp++;
464 *dp++ = *sp++;
465 *dp++ = *sp++;
466 *dp++ = *sp++;
467 *dp++ = *sp++;
468 *dp++ = *sp++;
469 }
470 }
471 row_info->pixel_depth = 48;
472 row_info->rowbytes = row_width * 6;
473 }
474 row_info->channels = 3;
475 }
476 else if ((row_info->color_type == PNG_COLOR_TYPE_GRAY ||
477 (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
478 (flags & PNG_FLAG_STRIP_ALPHA))) &&
479 row_info->channels == 2)
480 {
481 if (row_info->bit_depth == 8)
482 {
483 /* This converts from GX or GA to G */
484 if (flags & PNG_FLAG_FILLER_AFTER)
485 {
486 for (i = 0; i < row_width; i++)
487 {
488 *dp++ = *sp++;
489 sp++;
490 }
491 }
492 /* This converts from XG or AG to G */
493 else
494 {
495 for (i = 0; i < row_width; i++)
496 {
497 sp++;
498 *dp++ = *sp++;
499 }
500 }
501 row_info->pixel_depth = 8;
502 row_info->rowbytes = row_width;
503 }
504 else /* if (row_info->bit_depth == 16) */
505 {
506 if (flags & PNG_FLAG_FILLER_AFTER)
507 {
508 /* This converts from GGXX or GGAA to GG */
509 sp += 4; dp += 2;
510 for (i = 1; i < row_width; i++)
511 {
512 *dp++ = *sp++;
513 *dp++ = *sp++;
514 sp += 2;
515 }
516 }
517 else
518 {
519 /* This converts from XXGG or AAGG to GG */
520 for (i = 0; i < row_width; i++)
521 {
522 sp += 2;
523 *dp++ = *sp++;
524 *dp++ = *sp++;
525 }
526 }
527 row_info->pixel_depth = 16;
528 row_info->rowbytes = row_width * 2;
529 }
530 row_info->channels = 1;
531 }
532 if (flags & PNG_FLAG_STRIP_ALPHA)
533 row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
534 }
535}
536#endif
537
538#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
539/* swaps red and blue bytes within a pixel */
540void /* PRIVATE */
541png_do_bgr(png_row_infop row_info, png_bytep row)
542{
543 png_debug(1, "in png_do_bgr\n");
544 if (
545#if defined(PNG_USELESS_TESTS_SUPPORTED)
546 row != NULL && row_info != NULL &&
547#endif
548 (row_info->color_type & PNG_COLOR_MASK_COLOR))
549 {
550 png_uint_32 row_width = row_info->width;
551 if (row_info->bit_depth == 8)
552 {
553 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
554 {
555 png_bytep rp;
556 png_uint_32 i;
557
558 for (i = 0, rp = row; i < row_width; i++, rp += 3)
559 {
560 png_byte save = *rp;
561 *rp = *(rp + 2);
562 *(rp + 2) = save;
563 }
564 }
565 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
566 {
567 png_bytep rp;
568 png_uint_32 i;
569
570 for (i = 0, rp = row; i < row_width; i++, rp += 4)
571 {
572 png_byte save = *rp;
573 *rp = *(rp + 2);
574 *(rp + 2) = save;
575 }
576 }
577 }
578 else if (row_info->bit_depth == 16)
579 {
580 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
581 {
582 png_bytep rp;
583 png_uint_32 i;
584
585 for (i = 0, rp = row; i < row_width; i++, rp += 6)
586 {
587 png_byte save = *rp;
588 *rp = *(rp + 4);
589 *(rp + 4) = save;
590 save = *(rp + 1);
591 *(rp + 1) = *(rp + 5);
592 *(rp + 5) = save;
593 }
594 }
595 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
596 {
597 png_bytep rp;
598 png_uint_32 i;
599
600 for (i = 0, rp = row; i < row_width; i++, rp += 8)
601 {
602 png_byte save = *rp;
603 *rp = *(rp + 4);
604 *(rp + 4) = save;
605 save = *(rp + 1);
606 *(rp + 1) = *(rp + 5);
607 *(rp + 5) = save;
608 }
609 }
610 }
611 }
612}
613#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
614
615#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
616 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
617 defined(PNG_LEGACY_SUPPORTED)
618void PNGAPI
619png_set_user_transform_info(png_structp png_ptr, png_voidp
620 user_transform_ptr, int user_transform_depth, int user_transform_channels)
621{
622 png_debug(1, "in png_set_user_transform_info\n");
623#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
624 png_ptr->user_transform_ptr = user_transform_ptr;
625 png_ptr->user_transform_depth = (png_byte)user_transform_depth;
626 png_ptr->user_transform_channels = (png_byte)user_transform_channels;
627#else
628 if(user_transform_ptr || user_transform_depth || user_transform_channels)
629 png_warning(png_ptr,
630 "This version of libpng does not support user transform info");
631#endif
632}
633#endif
634
635/* This function returns a pointer to the user_transform_ptr associated with
636 * the user transform functions. The application should free any memory
637 * associated with this pointer before png_write_destroy and png_read_destroy
638 * are called.
639 */
640png_voidp PNGAPI
641png_get_user_transform_ptr(png_structp png_ptr)
642{
643#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
644 return ((png_voidp)png_ptr->user_transform_ptr);
645#else
646 if(png_ptr)
647 return (NULL);
648 return (NULL);
649#endif
650}
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