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1 /* pngtrans.c - transforms the data in a row (used by both readers and writers) | |
2 * | |
3 * Last changed in libpng 1.6.2 [April 25, 2013] | |
4 * Copyright (c) 1998-2013 Glenn Randers-Pehrson | |
5 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) | |
6 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) | |
7 * | |
8 * This code is released under the libpng license. | |
9 * For conditions of distribution and use, see the disclaimer | |
10 * and license in png.h | |
11 */ | |
12 | |
13 #include "pngpriv.h" | |
14 | |
15 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
16 | |
17 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) | |
18 /* Turn on BGR-to-RGB mapping */ | |
19 void PNGAPI | |
20 png_set_bgr(png_structrp png_ptr) | |
21 { | |
22 png_debug(1, "in png_set_bgr"); | |
23 | |
24 if (png_ptr == NULL) | |
25 return; | |
26 | |
27 png_ptr->transformations |= PNG_BGR; | |
28 } | |
29 #endif | |
30 | |
31 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) | |
32 /* Turn on 16 bit byte swapping */ | |
33 void PNGAPI | |
34 png_set_swap(png_structrp png_ptr) | |
35 { | |
36 png_debug(1, "in png_set_swap"); | |
37 | |
38 if (png_ptr == NULL) | |
39 return; | |
40 | |
41 if (png_ptr->bit_depth == 16) | |
42 png_ptr->transformations |= PNG_SWAP_BYTES; | |
43 } | |
44 #endif | |
45 | |
46 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) | |
47 /* Turn on pixel packing */ | |
48 void PNGAPI | |
49 png_set_packing(png_structrp png_ptr) | |
50 { | |
51 png_debug(1, "in png_set_packing"); | |
52 | |
53 if (png_ptr == NULL) | |
54 return; | |
55 | |
56 if (png_ptr->bit_depth < 8) | |
57 { | |
58 png_ptr->transformations |= PNG_PACK; | |
59 png_ptr->usr_bit_depth = 8; | |
60 } | |
61 } | |
62 #endif | |
63 | |
64 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) | |
65 /* Turn on packed pixel swapping */ | |
66 void PNGAPI | |
67 png_set_packswap(png_structrp png_ptr) | |
68 { | |
69 png_debug(1, "in png_set_packswap"); | |
70 | |
71 if (png_ptr == NULL) | |
72 return; | |
73 | |
74 if (png_ptr->bit_depth < 8) | |
75 png_ptr->transformations |= PNG_PACKSWAP; | |
76 } | |
77 #endif | |
78 | |
79 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) | |
80 void PNGAPI | |
81 png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits) | |
82 { | |
83 png_debug(1, "in png_set_shift"); | |
84 | |
85 if (png_ptr == NULL) | |
86 return; | |
87 | |
88 png_ptr->transformations |= PNG_SHIFT; | |
89 png_ptr->shift = *true_bits; | |
90 } | |
91 #endif | |
92 | |
93 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \ | |
94 defined(PNG_WRITE_INTERLACING_SUPPORTED) | |
95 int PNGAPI | |
96 png_set_interlace_handling(png_structrp png_ptr) | |
97 { | |
98 png_debug(1, "in png_set_interlace handling"); | |
99 | |
100 if (png_ptr && png_ptr->interlaced) | |
101 { | |
102 png_ptr->transformations |= PNG_INTERLACE; | |
103 return (7); | |
104 } | |
105 | |
106 return (1); | |
107 } | |
108 #endif | |
109 | |
110 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) | |
111 /* Add a filler byte on read, or remove a filler or alpha byte on write. | |
112 * The filler type has changed in v0.95 to allow future 2-byte fillers | |
113 * for 48-bit input data, as well as to avoid problems with some compilers | |
114 * that don't like bytes as parameters. | |
115 */ | |
116 void PNGAPI | |
117 png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc) | |
118 { | |
119 png_debug(1, "in png_set_filler"); | |
120 | |
121 if (png_ptr == NULL) | |
122 return; | |
123 | |
124 /* In libpng 1.6 it is possible to determine whether this is a read or write | |
125 * operation and therefore to do more checking here for a valid call. | |
126 */ | |
127 if (png_ptr->mode & PNG_IS_READ_STRUCT) | |
128 { | |
129 # ifdef PNG_READ_FILLER_SUPPORTED | |
130 /* On read png_set_filler is always valid, regardless of the base PNG | |
131 * format, because other transformations can give a format where the | |
132 * filler code can execute (basically an 8 or 16-bit component RGB or G | |
133 * format.) | |
134 * | |
135 * NOTE: usr_channels is not used by the read code! (This has led to | |
136 * confusion in the past.) The filler is only used in the read code. | |
137 */ | |
138 png_ptr->filler = (png_uint_16)filler; | |
139 # else | |
140 png_app_error(png_ptr, "png_set_filler not supported on read"); | |
141 PNG_UNUSED(filler) /* not used in the write case */ | |
142 return; | |
143 # endif | |
144 } | |
145 | |
146 else /* write */ | |
147 { | |
148 # ifdef PNG_WRITE_FILLER_SUPPORTED | |
149 /* On write the usr_channels parameter must be set correctly at the | |
150 * start to record the number of channels in the app-supplied data. | |
151 */ | |
152 switch (png_ptr->color_type) | |
153 { | |
154 case PNG_COLOR_TYPE_RGB: | |
155 png_ptr->usr_channels = 4; | |
156 break; | |
157 | |
158 case PNG_COLOR_TYPE_GRAY: | |
159 if (png_ptr->bit_depth >= 8) | |
160 { | |
161 png_ptr->usr_channels = 2; | |
162 break; | |
163 } | |
164 | |
165 else | |
166 { | |
167 /* There simply isn't any code in libpng to strip out bits | |
168 * from bytes when the components are less than a byte in | |
169 * size! | |
170 */ | |
171 png_app_error(png_ptr, | |
172 "png_set_filler is invalid for low bit depth gray output"); | |
173 return; | |
174 } | |
175 | |
176 default: | |
177 png_app_error(png_ptr, | |
178 "png_set_filler: inappropriate color type"); | |
179 return; | |
180 } | |
181 # else | |
182 png_app_error(png_ptr, "png_set_filler not supported on write"); | |
183 return; | |
184 # endif | |
185 } | |
186 | |
187 /* Here on success - libpng supports the operation, set the transformation | |
188 * and the flag to say where the filler channel is. | |
189 */ | |
190 png_ptr->transformations |= PNG_FILLER; | |
191 | |
192 if (filler_loc == PNG_FILLER_AFTER) | |
193 png_ptr->flags |= PNG_FLAG_FILLER_AFTER; | |
194 | |
195 else | |
196 png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER; | |
197 } | |
198 | |
199 /* Added to libpng-1.2.7 */ | |
200 void PNGAPI | |
201 png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc) | |
202 { | |
203 png_debug(1, "in png_set_add_alpha"); | |
204 | |
205 if (png_ptr == NULL) | |
206 return; | |
207 | |
208 png_set_filler(png_ptr, filler, filler_loc); | |
209 /* The above may fail to do anything. */ | |
210 if (png_ptr->transformations & PNG_FILLER) | |
211 png_ptr->transformations |= PNG_ADD_ALPHA; | |
212 } | |
213 | |
214 #endif | |
215 | |
216 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ | |
217 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) | |
218 void PNGAPI | |
219 png_set_swap_alpha(png_structrp png_ptr) | |
220 { | |
221 png_debug(1, "in png_set_swap_alpha"); | |
222 | |
223 if (png_ptr == NULL) | |
224 return; | |
225 | |
226 png_ptr->transformations |= PNG_SWAP_ALPHA; | |
227 } | |
228 #endif | |
229 | |
230 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ | |
231 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) | |
232 void PNGAPI | |
233 png_set_invert_alpha(png_structrp png_ptr) | |
234 { | |
235 png_debug(1, "in png_set_invert_alpha"); | |
236 | |
237 if (png_ptr == NULL) | |
238 return; | |
239 | |
240 png_ptr->transformations |= PNG_INVERT_ALPHA; | |
241 } | |
242 #endif | |
243 | |
244 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) | |
245 void PNGAPI | |
246 png_set_invert_mono(png_structrp png_ptr) | |
247 { | |
248 png_debug(1, "in png_set_invert_mono"); | |
249 | |
250 if (png_ptr == NULL) | |
251 return; | |
252 | |
253 png_ptr->transformations |= PNG_INVERT_MONO; | |
254 } | |
255 | |
256 /* Invert monochrome grayscale data */ | |
257 void /* PRIVATE */ | |
258 png_do_invert(png_row_infop row_info, png_bytep row) | |
259 { | |
260 png_debug(1, "in png_do_invert"); | |
261 | |
262 /* This test removed from libpng version 1.0.13 and 1.2.0: | |
263 * if (row_info->bit_depth == 1 && | |
264 */ | |
265 if (row_info->color_type == PNG_COLOR_TYPE_GRAY) | |
266 { | |
267 png_bytep rp = row; | |
268 png_size_t i; | |
269 png_size_t istop = row_info->rowbytes; | |
270 | |
271 for (i = 0; i < istop; i++) | |
272 { | |
273 *rp = (png_byte)(~(*rp)); | |
274 rp++; | |
275 } | |
276 } | |
277 | |
278 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
279 row_info->bit_depth == 8) | |
280 { | |
281 png_bytep rp = row; | |
282 png_size_t i; | |
283 png_size_t istop = row_info->rowbytes; | |
284 | |
285 for (i = 0; i < istop; i += 2) | |
286 { | |
287 *rp = (png_byte)(~(*rp)); | |
288 rp += 2; | |
289 } | |
290 } | |
291 | |
292 #ifdef PNG_16BIT_SUPPORTED | |
293 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
294 row_info->bit_depth == 16) | |
295 { | |
296 png_bytep rp = row; | |
297 png_size_t i; | |
298 png_size_t istop = row_info->rowbytes; | |
299 | |
300 for (i = 0; i < istop; i += 4) | |
301 { | |
302 *rp = (png_byte)(~(*rp)); | |
303 *(rp + 1) = (png_byte)(~(*(rp + 1))); | |
304 rp += 4; | |
305 } | |
306 } | |
307 #endif | |
308 } | |
309 #endif | |
310 | |
311 #ifdef PNG_16BIT_SUPPORTED | |
312 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) | |
313 /* Swaps byte order on 16 bit depth images */ | |
314 void /* PRIVATE */ | |
315 png_do_swap(png_row_infop row_info, png_bytep row) | |
316 { | |
317 png_debug(1, "in png_do_swap"); | |
318 | |
319 if (row_info->bit_depth == 16) | |
320 { | |
321 png_bytep rp = row; | |
322 png_uint_32 i; | |
323 png_uint_32 istop= row_info->width * row_info->channels; | |
324 | |
325 for (i = 0; i < istop; i++, rp += 2) | |
326 { | |
327 png_byte t = *rp; | |
328 *rp = *(rp + 1); | |
329 *(rp + 1) = t; | |
330 } | |
331 } | |
332 } | |
333 #endif | |
334 #endif | |
335 | |
336 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) | |
337 static PNG_CONST png_byte onebppswaptable[256] = { | |
338 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, | |
339 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, | |
340 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, | |
341 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, | |
342 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, | |
343 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, | |
344 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, | |
345 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, | |
346 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, | |
347 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, | |
348 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, | |
349 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, | |
350 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, | |
351 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, | |
352 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, | |
353 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, | |
354 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, | |
355 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, | |
356 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, | |
357 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, | |
358 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, | |
359 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, | |
360 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, | |
361 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD, | |
362 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, | |
363 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, | |
364 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, | |
365 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, | |
366 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, | |
367 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, | |
368 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, | |
369 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF | |
370 }; | |
371 | |
372 static PNG_CONST png_byte twobppswaptable[256] = { | |
373 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0, | |
374 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0, | |
375 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4, | |
376 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4, | |
377 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8, | |
378 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8, | |
379 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC, | |
380 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC, | |
381 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1, | |
382 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1, | |
383 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5, | |
384 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5, | |
385 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9, | |
386 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9, | |
387 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD, | |
388 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD, | |
389 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2, | |
390 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2, | |
391 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6, | |
392 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6, | |
393 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA, | |
394 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA, | |
395 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE, | |
396 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE, | |
397 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3, | |
398 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3, | |
399 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7, | |
400 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7, | |
401 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB, | |
402 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB, | |
403 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF, | |
404 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF | |
405 }; | |
406 | |
407 static PNG_CONST png_byte fourbppswaptable[256] = { | |
408 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, | |
409 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0, | |
410 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, | |
411 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1, | |
412 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, | |
413 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2, | |
414 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, | |
415 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3, | |
416 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, | |
417 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4, | |
418 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, | |
419 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5, | |
420 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, | |
421 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6, | |
422 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, | |
423 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7, | |
424 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, | |
425 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8, | |
426 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, | |
427 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9, | |
428 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, | |
429 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA, | |
430 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, | |
431 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB, | |
432 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, | |
433 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC, | |
434 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, | |
435 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD, | |
436 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, | |
437 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE, | |
438 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, | |
439 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF | |
440 }; | |
441 | |
442 /* Swaps pixel packing order within bytes */ | |
443 void /* PRIVATE */ | |
444 png_do_packswap(png_row_infop row_info, png_bytep row) | |
445 { | |
446 png_debug(1, "in png_do_packswap"); | |
447 | |
448 if (row_info->bit_depth < 8) | |
449 { | |
450 png_bytep rp; | |
451 png_const_bytep end, table; | |
452 | |
453 end = row + row_info->rowbytes; | |
454 | |
455 if (row_info->bit_depth == 1) | |
456 table = onebppswaptable; | |
457 | |
458 else if (row_info->bit_depth == 2) | |
459 table = twobppswaptable; | |
460 | |
461 else if (row_info->bit_depth == 4) | |
462 table = fourbppswaptable; | |
463 | |
464 else | |
465 return; | |
466 | |
467 for (rp = row; rp < end; rp++) | |
468 *rp = table[*rp]; | |
469 } | |
470 } | |
471 #endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */ | |
472 | |
473 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \ | |
474 defined(PNG_READ_STRIP_ALPHA_SUPPORTED) | |
475 /* Remove a channel - this used to be 'png_do_strip_filler' but it used a | |
476 * somewhat weird combination of flags to determine what to do. All the calls | |
477 * to png_do_strip_filler are changed in 1.5.2 to call this instead with the | |
478 * correct arguments. | |
479 * | |
480 * The routine isn't general - the channel must be the channel at the start or | |
481 * end (not in the middle) of each pixel. | |
482 */ | |
483 void /* PRIVATE */ | |
484 png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start) | |
485 { | |
486 png_bytep sp = row; /* source pointer */ | |
487 png_bytep dp = row; /* destination pointer */ | |
488 png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */ | |
489 | |
490 /* At the start sp will point to the first byte to copy and dp to where | |
491 * it is copied to. ep always points just beyond the end of the row, so | |
492 * the loop simply copies (channels-1) channels until sp reaches ep. | |
493 * | |
494 * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc. | |
495 * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc. | |
496 */ | |
497 | |
498 /* GA, GX, XG cases */ | |
499 if (row_info->channels == 2) | |
500 { | |
501 if (row_info->bit_depth == 8) | |
502 { | |
503 if (at_start) /* Skip initial filler */ | |
504 ++sp; | |
505 else /* Skip initial channel and, for sp, the filler */ | |
506 sp += 2, ++dp; | |
507 | |
508 /* For a 1 pixel wide image there is nothing to do */ | |
509 while (sp < ep) | |
510 *dp++ = *sp, sp += 2; | |
511 | |
512 row_info->pixel_depth = 8; | |
513 } | |
514 | |
515 else if (row_info->bit_depth == 16) | |
516 { | |
517 if (at_start) /* Skip initial filler */ | |
518 sp += 2; | |
519 else /* Skip initial channel and, for sp, the filler */ | |
520 sp += 4, dp += 2; | |
521 | |
522 while (sp < ep) | |
523 *dp++ = *sp++, *dp++ = *sp, sp += 3; | |
524 | |
525 row_info->pixel_depth = 16; | |
526 } | |
527 | |
528 else | |
529 return; /* bad bit depth */ | |
530 | |
531 row_info->channels = 1; | |
532 | |
533 /* Finally fix the color type if it records an alpha channel */ | |
534 if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
535 row_info->color_type = PNG_COLOR_TYPE_GRAY; | |
536 } | |
537 | |
538 /* RGBA, RGBX, XRGB cases */ | |
539 else if (row_info->channels == 4) | |
540 { | |
541 if (row_info->bit_depth == 8) | |
542 { | |
543 if (at_start) /* Skip initial filler */ | |
544 ++sp; | |
545 else /* Skip initial channels and, for sp, the filler */ | |
546 sp += 4, dp += 3; | |
547 | |
548 /* Note that the loop adds 3 to dp and 4 to sp each time. */ | |
549 while (sp < ep) | |
550 *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2; | |
551 | |
552 row_info->pixel_depth = 24; | |
553 } | |
554 | |
555 else if (row_info->bit_depth == 16) | |
556 { | |
557 if (at_start) /* Skip initial filler */ | |
558 sp += 2; | |
559 else /* Skip initial channels and, for sp, the filler */ | |
560 sp += 8, dp += 6; | |
561 | |
562 while (sp < ep) | |
563 { | |
564 /* Copy 6 bytes, skip 2 */ | |
565 *dp++ = *sp++, *dp++ = *sp++; | |
566 *dp++ = *sp++, *dp++ = *sp++; | |
567 *dp++ = *sp++, *dp++ = *sp, sp += 3; | |
568 } | |
569 | |
570 row_info->pixel_depth = 48; | |
571 } | |
572 | |
573 else | |
574 return; /* bad bit depth */ | |
575 | |
576 row_info->channels = 3; | |
577 | |
578 /* Finally fix the color type if it records an alpha channel */ | |
579 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
580 row_info->color_type = PNG_COLOR_TYPE_RGB; | |
581 } | |
582 | |
583 else | |
584 return; /* The filler channel has gone already */ | |
585 | |
586 /* Fix the rowbytes value. */ | |
587 row_info->rowbytes = dp-row; | |
588 } | |
589 #endif | |
590 | |
591 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) | |
592 /* Swaps red and blue bytes within a pixel */ | |
593 void /* PRIVATE */ | |
594 png_do_bgr(png_row_infop row_info, png_bytep row) | |
595 { | |
596 png_debug(1, "in png_do_bgr"); | |
597 | |
598 if ((row_info->color_type & PNG_COLOR_MASK_COLOR)) | |
599 { | |
600 png_uint_32 row_width = row_info->width; | |
601 if (row_info->bit_depth == 8) | |
602 { | |
603 if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
604 { | |
605 png_bytep rp; | |
606 png_uint_32 i; | |
607 | |
608 for (i = 0, rp = row; i < row_width; i++, rp += 3) | |
609 { | |
610 png_byte save = *rp; | |
611 *rp = *(rp + 2); | |
612 *(rp + 2) = save; | |
613 } | |
614 } | |
615 | |
616 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
617 { | |
618 png_bytep rp; | |
619 png_uint_32 i; | |
620 | |
621 for (i = 0, rp = row; i < row_width; i++, rp += 4) | |
622 { | |
623 png_byte save = *rp; | |
624 *rp = *(rp + 2); | |
625 *(rp + 2) = save; | |
626 } | |
627 } | |
628 } | |
629 | |
630 #ifdef PNG_16BIT_SUPPORTED | |
631 else if (row_info->bit_depth == 16) | |
632 { | |
633 if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
634 { | |
635 png_bytep rp; | |
636 png_uint_32 i; | |
637 | |
638 for (i = 0, rp = row; i < row_width; i++, rp += 6) | |
639 { | |
640 png_byte save = *rp; | |
641 *rp = *(rp + 4); | |
642 *(rp + 4) = save; | |
643 save = *(rp + 1); | |
644 *(rp + 1) = *(rp + 5); | |
645 *(rp + 5) = save; | |
646 } | |
647 } | |
648 | |
649 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
650 { | |
651 png_bytep rp; | |
652 png_uint_32 i; | |
653 | |
654 for (i = 0, rp = row; i < row_width; i++, rp += 8) | |
655 { | |
656 png_byte save = *rp; | |
657 *rp = *(rp + 4); | |
658 *(rp + 4) = save; | |
659 save = *(rp + 1); | |
660 *(rp + 1) = *(rp + 5); | |
661 *(rp + 5) = save; | |
662 } | |
663 } | |
664 } | |
665 #endif | |
666 } | |
667 } | |
668 #endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */ | |
669 | |
670 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \ | |
671 defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED) | |
672 /* Added at libpng-1.5.10 */ | |
673 void /* PRIVATE */ | |
674 png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info) | |
675 { | |
676 if (png_ptr->num_palette < (1 << row_info->bit_depth) && | |
677 png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */ | |
678 { | |
679 /* Calculations moved outside switch in an attempt to stop different | |
680 * compiler warnings. 'padding' is in *bits* within the last byte, it is | |
681 * an 'int' because pixel_depth becomes an 'int' in the expression below, | |
682 * and this calculation is used because it avoids warnings that other | |
683 * forms produced on either GCC or MSVC. | |
684 */ | |
685 int padding = (-row_info->pixel_depth * row_info->width) & 7; | |
686 png_bytep rp = png_ptr->row_buf + row_info->rowbytes; | |
687 | |
688 switch (row_info->bit_depth) | |
689 { | |
690 case 1: | |
691 { | |
692 /* in this case, all bytes must be 0 so we don't need | |
693 * to unpack the pixels except for the rightmost one. | |
694 */ | |
695 for (; rp > png_ptr->row_buf; rp--) | |
696 { | |
697 if (*rp >> padding != 0) | |
698 png_ptr->num_palette_max = 1; | |
699 padding = 0; | |
700 } | |
701 | |
702 break; | |
703 } | |
704 | |
705 case 2: | |
706 { | |
707 for (; rp > png_ptr->row_buf; rp--) | |
708 { | |
709 int i = ((*rp >> padding) & 0x03); | |
710 | |
711 if (i > png_ptr->num_palette_max) | |
712 png_ptr->num_palette_max = i; | |
713 | |
714 i = (((*rp >> padding) >> 2) & 0x03); | |
715 | |
716 if (i > png_ptr->num_palette_max) | |
717 png_ptr->num_palette_max = i; | |
718 | |
719 i = (((*rp >> padding) >> 4) & 0x03); | |
720 | |
721 if (i > png_ptr->num_palette_max) | |
722 png_ptr->num_palette_max = i; | |
723 | |
724 i = (((*rp >> padding) >> 6) & 0x03); | |
725 | |
726 if (i > png_ptr->num_palette_max) | |
727 png_ptr->num_palette_max = i; | |
728 | |
729 padding = 0; | |
730 } | |
731 | |
732 break; | |
733 } | |
734 | |
735 case 4: | |
736 { | |
737 for (; rp > png_ptr->row_buf; rp--) | |
738 { | |
739 int i = ((*rp >> padding) & 0x0f); | |
740 | |
741 if (i > png_ptr->num_palette_max) | |
742 png_ptr->num_palette_max = i; | |
743 | |
744 i = (((*rp >> padding) >> 4) & 0x0f); | |
745 | |
746 if (i > png_ptr->num_palette_max) | |
747 png_ptr->num_palette_max = i; | |
748 | |
749 padding = 0; | |
750 } | |
751 | |
752 break; | |
753 } | |
754 | |
755 case 8: | |
756 { | |
757 for (; rp > png_ptr->row_buf; rp--) | |
758 { | |
759 if (*rp > png_ptr->num_palette_max) | |
760 png_ptr->num_palette_max = (int) *rp; | |
761 } | |
762 | |
763 break; | |
764 } | |
765 | |
766 default: | |
767 break; | |
768 } | |
769 } | |
770 } | |
771 #endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */ | |
772 | |
773 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ | |
774 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) | |
775 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED | |
776 void PNGAPI | |
777 png_set_user_transform_info(png_structrp png_ptr, png_voidp | |
778 user_transform_ptr, int user_transform_depth, int user_transform_channels) | |
779 { | |
780 png_debug(1, "in png_set_user_transform_info"); | |
781 | |
782 if (png_ptr == NULL) | |
783 return; | |
784 | |
785 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED | |
786 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
787 (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0) | |
788 { | |
789 png_app_error(png_ptr, | |
790 "info change after png_start_read_image or png_read_update_info"); | |
791 return; | |
792 } | |
793 #endif | |
794 | |
795 png_ptr->user_transform_ptr = user_transform_ptr; | |
796 png_ptr->user_transform_depth = (png_byte)user_transform_depth; | |
797 png_ptr->user_transform_channels = (png_byte)user_transform_channels; | |
798 } | |
799 #endif | |
800 | |
801 /* This function returns a pointer to the user_transform_ptr associated with | |
802 * the user transform functions. The application should free any memory | |
803 * associated with this pointer before png_write_destroy and png_read_destroy | |
804 * are called. | |
805 */ | |
806 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED | |
807 png_voidp PNGAPI | |
808 png_get_user_transform_ptr(png_const_structrp png_ptr) | |
809 { | |
810 if (png_ptr == NULL) | |
811 return (NULL); | |
812 | |
813 return png_ptr->user_transform_ptr; | |
814 } | |
815 #endif | |
816 | |
817 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED | |
818 png_uint_32 PNGAPI | |
819 png_get_current_row_number(png_const_structrp png_ptr) | |
820 { | |
821 /* See the comments in png.h - this is the sub-image row when reading and | |
822 * interlaced image. | |
823 */ | |
824 if (png_ptr != NULL) | |
825 return png_ptr->row_number; | |
826 | |
827 return PNG_UINT_32_MAX; /* help the app not to fail silently */ | |
828 } | |
829 | |
830 png_byte PNGAPI | |
831 png_get_current_pass_number(png_const_structrp png_ptr) | |
832 { | |
833 if (png_ptr != NULL) | |
834 return png_ptr->pass; | |
835 return 8; /* invalid */ | |
836 } | |
837 #endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */ | |
838 #endif /* PNG_READ_USER_TRANSFORM_SUPPORTED || | |
839 PNG_WRITE_USER_TRANSFORM_SUPPORTED */ | |
840 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ | |
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