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1 | |
2 /* pngtrans.c - transforms the data in a row (used by both readers and writers) | |
3 * | |
4 * Last changed in libpng 1.6.18 [July 23, 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 | |
14 #include "pngpriv.h" | |
15 | |
16 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
17 | |
18 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) | |
19 /* Turn on BGR-to-RGB mapping */ | |
20 void PNGAPI | |
21 png_set_bgr(png_structrp png_ptr) | |
22 { | |
23 png_debug(1, "in png_set_bgr"); | |
24 | |
25 if (png_ptr == NULL) | |
26 return; | |
27 | |
28 png_ptr->transformations |= PNG_BGR; | |
29 } | |
30 #endif | |
31 | |
32 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) | |
33 /* Turn on 16-bit byte swapping */ | |
34 void PNGAPI | |
35 png_set_swap(png_structrp png_ptr) | |
36 { | |
37 png_debug(1, "in png_set_swap"); | |
38 | |
39 if (png_ptr == NULL) | |
40 return; | |
41 | |
42 if (png_ptr->bit_depth == 16) | |
43 png_ptr->transformations |= PNG_SWAP_BYTES; | |
44 } | |
45 #endif | |
46 | |
47 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) | |
48 /* Turn on pixel packing */ | |
49 void PNGAPI | |
50 png_set_packing(png_structrp png_ptr) | |
51 { | |
52 png_debug(1, "in png_set_packing"); | |
53 | |
54 if (png_ptr == NULL) | |
55 return; | |
56 | |
57 if (png_ptr->bit_depth < 8) | |
58 { | |
59 png_ptr->transformations |= PNG_PACK; | |
60 # ifdef PNG_WRITE_SUPPORTED | |
61 png_ptr->usr_bit_depth = 8; | |
62 # endif | |
63 } | |
64 } | |
65 #endif | |
66 | |
67 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) | |
68 /* Turn on packed pixel swapping */ | |
69 void PNGAPI | |
70 png_set_packswap(png_structrp png_ptr) | |
71 { | |
72 png_debug(1, "in png_set_packswap"); | |
73 | |
74 if (png_ptr == NULL) | |
75 return; | |
76 | |
77 if (png_ptr->bit_depth < 8) | |
78 png_ptr->transformations |= PNG_PACKSWAP; | |
79 } | |
80 #endif | |
81 | |
82 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) | |
83 void PNGAPI | |
84 png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits) | |
85 { | |
86 png_debug(1, "in png_set_shift"); | |
87 | |
88 if (png_ptr == NULL) | |
89 return; | |
90 | |
91 png_ptr->transformations |= PNG_SHIFT; | |
92 png_ptr->shift = *true_bits; | |
93 } | |
94 #endif | |
95 | |
96 #if defined(PNG_READ_INTERLACING_SUPPORTED) || \ | |
97 defined(PNG_WRITE_INTERLACING_SUPPORTED) | |
98 int PNGAPI | |
99 png_set_interlace_handling(png_structrp png_ptr) | |
100 { | |
101 png_debug(1, "in png_set_interlace handling"); | |
102 | |
103 if (png_ptr != 0 && png_ptr->interlaced != 0) | |
104 { | |
105 png_ptr->transformations |= PNG_INTERLACE; | |
106 return (7); | |
107 } | |
108 | |
109 return (1); | |
110 } | |
111 #endif | |
112 | |
113 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) | |
114 /* Add a filler byte on read, or remove a filler or alpha byte on write. | |
115 * The filler type has changed in v0.95 to allow future 2-byte fillers | |
116 * for 48-bit input data, as well as to avoid problems with some compilers | |
117 * that don't like bytes as parameters. | |
118 */ | |
119 void PNGAPI | |
120 png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc) | |
121 { | |
122 png_debug(1, "in png_set_filler"); | |
123 | |
124 if (png_ptr == NULL) | |
125 return; | |
126 | |
127 /* In libpng 1.6 it is possible to determine whether this is a read or write | |
128 * operation and therefore to do more checking here for a valid call. | |
129 */ | |
130 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0) | |
131 { | |
132 # ifdef PNG_READ_FILLER_SUPPORTED | |
133 /* On read png_set_filler is always valid, regardless of the base PNG | |
134 * format, because other transformations can give a format where the | |
135 * filler code can execute (basically an 8 or 16-bit component RGB or G | |
136 * format.) | |
137 * | |
138 * NOTE: usr_channels is not used by the read code! (This has led to | |
139 * confusion in the past.) The filler is only used in the read code. | |
140 */ | |
141 png_ptr->filler = (png_uint_16)filler; | |
142 # else | |
143 png_app_error(png_ptr, "png_set_filler not supported on read"); | |
144 PNG_UNUSED(filler) /* not used in the write case */ | |
145 return; | |
146 # endif | |
147 } | |
148 | |
149 else /* write */ | |
150 { | |
151 # ifdef PNG_WRITE_FILLER_SUPPORTED | |
152 /* On write the usr_channels parameter must be set correctly at the | |
153 * start to record the number of channels in the app-supplied data. | |
154 */ | |
155 switch (png_ptr->color_type) | |
156 { | |
157 case PNG_COLOR_TYPE_RGB: | |
158 png_ptr->usr_channels = 4; | |
159 break; | |
160 | |
161 case PNG_COLOR_TYPE_GRAY: | |
162 if (png_ptr->bit_depth >= 8) | |
163 { | |
164 png_ptr->usr_channels = 2; | |
165 break; | |
166 } | |
167 | |
168 else | |
169 { | |
170 /* There simply isn't any code in libpng to strip out bits | |
171 * from bytes when the components are less than a byte in | |
172 * size! | |
173 */ | |
174 png_app_error(png_ptr, | |
175 "png_set_filler is invalid for low bit depth gray output"); | |
176 return; | |
177 } | |
178 | |
179 default: | |
180 png_app_error(png_ptr, | |
181 "png_set_filler: inappropriate color type"); | |
182 return; | |
183 } | |
184 # else | |
185 png_app_error(png_ptr, "png_set_filler not supported on write"); | |
186 return; | |
187 # endif | |
188 } | |
189 | |
190 /* Here on success - libpng supports the operation, set the transformation | |
191 * and the flag to say where the filler channel is. | |
192 */ | |
193 png_ptr->transformations |= PNG_FILLER; | |
194 | |
195 if (filler_loc == PNG_FILLER_AFTER) | |
196 png_ptr->flags |= PNG_FLAG_FILLER_AFTER; | |
197 | |
198 else | |
199 png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER; | |
200 } | |
201 | |
202 /* Added to libpng-1.2.7 */ | |
203 void PNGAPI | |
204 png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc) | |
205 { | |
206 png_debug(1, "in png_set_add_alpha"); | |
207 | |
208 if (png_ptr == NULL) | |
209 return; | |
210 | |
211 png_set_filler(png_ptr, filler, filler_loc); | |
212 /* The above may fail to do anything. */ | |
213 if ((png_ptr->transformations & PNG_FILLER) != 0) | |
214 png_ptr->transformations |= PNG_ADD_ALPHA; | |
215 } | |
216 | |
217 #endif | |
218 | |
219 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ | |
220 defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) | |
221 void PNGAPI | |
222 png_set_swap_alpha(png_structrp png_ptr) | |
223 { | |
224 png_debug(1, "in png_set_swap_alpha"); | |
225 | |
226 if (png_ptr == NULL) | |
227 return; | |
228 | |
229 png_ptr->transformations |= PNG_SWAP_ALPHA; | |
230 } | |
231 #endif | |
232 | |
233 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ | |
234 defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) | |
235 void PNGAPI | |
236 png_set_invert_alpha(png_structrp png_ptr) | |
237 { | |
238 png_debug(1, "in png_set_invert_alpha"); | |
239 | |
240 if (png_ptr == NULL) | |
241 return; | |
242 | |
243 png_ptr->transformations |= PNG_INVERT_ALPHA; | |
244 } | |
245 #endif | |
246 | |
247 #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) | |
248 void PNGAPI | |
249 png_set_invert_mono(png_structrp png_ptr) | |
250 { | |
251 png_debug(1, "in png_set_invert_mono"); | |
252 | |
253 if (png_ptr == NULL) | |
254 return; | |
255 | |
256 png_ptr->transformations |= PNG_INVERT_MONO; | |
257 } | |
258 | |
259 /* Invert monochrome grayscale data */ | |
260 void /* PRIVATE */ | |
261 png_do_invert(png_row_infop row_info, png_bytep row) | |
262 { | |
263 png_debug(1, "in png_do_invert"); | |
264 | |
265 /* This test removed from libpng version 1.0.13 and 1.2.0: | |
266 * if (row_info->bit_depth == 1 && | |
267 */ | |
268 if (row_info->color_type == PNG_COLOR_TYPE_GRAY) | |
269 { | |
270 png_bytep rp = row; | |
271 png_size_t i; | |
272 png_size_t istop = row_info->rowbytes; | |
273 | |
274 for (i = 0; i < istop; i++) | |
275 { | |
276 *rp = (png_byte)(~(*rp)); | |
277 rp++; | |
278 } | |
279 } | |
280 | |
281 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
282 row_info->bit_depth == 8) | |
283 { | |
284 png_bytep rp = row; | |
285 png_size_t i; | |
286 png_size_t istop = row_info->rowbytes; | |
287 | |
288 for (i = 0; i < istop; i += 2) | |
289 { | |
290 *rp = (png_byte)(~(*rp)); | |
291 rp += 2; | |
292 } | |
293 } | |
294 | |
295 #ifdef PNG_16BIT_SUPPORTED | |
296 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && | |
297 row_info->bit_depth == 16) | |
298 { | |
299 png_bytep rp = row; | |
300 png_size_t i; | |
301 png_size_t istop = row_info->rowbytes; | |
302 | |
303 for (i = 0; i < istop; i += 4) | |
304 { | |
305 *rp = (png_byte)(~(*rp)); | |
306 *(rp + 1) = (png_byte)(~(*(rp + 1))); | |
307 rp += 4; | |
308 } | |
309 } | |
310 #endif | |
311 } | |
312 #endif | |
313 | |
314 #ifdef PNG_16BIT_SUPPORTED | |
315 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) | |
316 /* Swaps byte order on 16-bit depth images */ | |
317 void /* PRIVATE */ | |
318 png_do_swap(png_row_infop row_info, png_bytep row) | |
319 { | |
320 png_debug(1, "in png_do_swap"); | |
321 | |
322 if (row_info->bit_depth == 16) | |
323 { | |
324 png_bytep rp = row; | |
325 png_uint_32 i; | |
326 png_uint_32 istop= row_info->width * row_info->channels; | |
327 | |
328 for (i = 0; i < istop; i++, rp += 2) | |
329 { | |
330 #ifdef PNG_BUILTIN_BSWAP16_SUPPORTED | |
331 /* Feature added to libpng-1.6.11 for testing purposes, not | |
332 * enabled by default. | |
333 */ | |
334 *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp); | |
335 #else | |
336 png_byte t = *rp; | |
337 *rp = *(rp + 1); | |
338 *(rp + 1) = t; | |
339 #endif | |
340 } | |
341 } | |
342 } | |
343 #endif | |
344 #endif | |
345 | |
346 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) | |
347 static PNG_CONST png_byte onebppswaptable[256] = { | |
348 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, | |
349 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, | |
350 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, | |
351 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, | |
352 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, | |
353 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, | |
354 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, | |
355 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, | |
356 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, | |
357 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, | |
358 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, | |
359 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, | |
360 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, | |
361 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, | |
362 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, | |
363 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, | |
364 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, | |
365 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, | |
366 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, | |
367 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, | |
368 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, | |
369 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, | |
370 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, | |
371 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD, | |
372 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, | |
373 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, | |
374 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, | |
375 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, | |
376 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, | |
377 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, | |
378 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, | |
379 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF | |
380 }; | |
381 | |
382 static PNG_CONST png_byte twobppswaptable[256] = { | |
383 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0, | |
384 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0, | |
385 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4, | |
386 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4, | |
387 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8, | |
388 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8, | |
389 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC, | |
390 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC, | |
391 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1, | |
392 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1, | |
393 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5, | |
394 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5, | |
395 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9, | |
396 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9, | |
397 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD, | |
398 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD, | |
399 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2, | |
400 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2, | |
401 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6, | |
402 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6, | |
403 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA, | |
404 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA, | |
405 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE, | |
406 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE, | |
407 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3, | |
408 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3, | |
409 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7, | |
410 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7, | |
411 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB, | |
412 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB, | |
413 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF, | |
414 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF | |
415 }; | |
416 | |
417 static PNG_CONST png_byte fourbppswaptable[256] = { | |
418 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, | |
419 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0, | |
420 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, | |
421 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1, | |
422 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, | |
423 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2, | |
424 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, | |
425 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3, | |
426 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, | |
427 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4, | |
428 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, | |
429 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5, | |
430 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, | |
431 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6, | |
432 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, | |
433 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7, | |
434 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, | |
435 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8, | |
436 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, | |
437 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9, | |
438 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, | |
439 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA, | |
440 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, | |
441 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB, | |
442 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, | |
443 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC, | |
444 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, | |
445 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD, | |
446 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, | |
447 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE, | |
448 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, | |
449 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF | |
450 }; | |
451 | |
452 /* Swaps pixel packing order within bytes */ | |
453 void /* PRIVATE */ | |
454 png_do_packswap(png_row_infop row_info, png_bytep row) | |
455 { | |
456 png_debug(1, "in png_do_packswap"); | |
457 | |
458 if (row_info->bit_depth < 8) | |
459 { | |
460 png_bytep rp; | |
461 png_const_bytep end, table; | |
462 | |
463 end = row + row_info->rowbytes; | |
464 | |
465 if (row_info->bit_depth == 1) | |
466 table = onebppswaptable; | |
467 | |
468 else if (row_info->bit_depth == 2) | |
469 table = twobppswaptable; | |
470 | |
471 else if (row_info->bit_depth == 4) | |
472 table = fourbppswaptable; | |
473 | |
474 else | |
475 return; | |
476 | |
477 for (rp = row; rp < end; rp++) | |
478 *rp = table[*rp]; | |
479 } | |
480 } | |
481 #endif /* PACKSWAP || WRITE_PACKSWAP */ | |
482 | |
483 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \ | |
484 defined(PNG_READ_STRIP_ALPHA_SUPPORTED) | |
485 /* Remove a channel - this used to be 'png_do_strip_filler' but it used a | |
486 * somewhat weird combination of flags to determine what to do. All the calls | |
487 * to png_do_strip_filler are changed in 1.5.2 to call this instead with the | |
488 * correct arguments. | |
489 * | |
490 * The routine isn't general - the channel must be the channel at the start or | |
491 * end (not in the middle) of each pixel. | |
492 */ | |
493 void /* PRIVATE */ | |
494 png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start) | |
495 { | |
496 png_bytep sp = row; /* source pointer */ | |
497 png_bytep dp = row; /* destination pointer */ | |
498 png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */ | |
499 | |
500 /* At the start sp will point to the first byte to copy and dp to where | |
501 * it is copied to. ep always points just beyond the end of the row, so | |
502 * the loop simply copies (channels-1) channels until sp reaches ep. | |
503 * | |
504 * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc. | |
505 * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc. | |
506 */ | |
507 | |
508 /* GA, GX, XG cases */ | |
509 if (row_info->channels == 2) | |
510 { | |
511 if (row_info->bit_depth == 8) | |
512 { | |
513 if (at_start != 0) /* Skip initial filler */ | |
514 ++sp; | |
515 else /* Skip initial channel and, for sp, the filler */ | |
516 sp += 2, ++dp; | |
517 | |
518 /* For a 1 pixel wide image there is nothing to do */ | |
519 while (sp < ep) | |
520 *dp++ = *sp, sp += 2; | |
521 | |
522 row_info->pixel_depth = 8; | |
523 } | |
524 | |
525 else if (row_info->bit_depth == 16) | |
526 { | |
527 if (at_start != 0) /* Skip initial filler */ | |
528 sp += 2; | |
529 else /* Skip initial channel and, for sp, the filler */ | |
530 sp += 4, dp += 2; | |
531 | |
532 while (sp < ep) | |
533 *dp++ = *sp++, *dp++ = *sp, sp += 3; | |
534 | |
535 row_info->pixel_depth = 16; | |
536 } | |
537 | |
538 else | |
539 return; /* bad bit depth */ | |
540 | |
541 row_info->channels = 1; | |
542 | |
543 /* Finally fix the color type if it records an alpha channel */ | |
544 if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
545 row_info->color_type = PNG_COLOR_TYPE_GRAY; | |
546 } | |
547 | |
548 /* RGBA, RGBX, XRGB cases */ | |
549 else if (row_info->channels == 4) | |
550 { | |
551 if (row_info->bit_depth == 8) | |
552 { | |
553 if (at_start != 0) /* Skip initial filler */ | |
554 ++sp; | |
555 else /* Skip initial channels and, for sp, the filler */ | |
556 sp += 4, dp += 3; | |
557 | |
558 /* Note that the loop adds 3 to dp and 4 to sp each time. */ | |
559 while (sp < ep) | |
560 *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2; | |
561 | |
562 row_info->pixel_depth = 24; | |
563 } | |
564 | |
565 else if (row_info->bit_depth == 16) | |
566 { | |
567 if (at_start != 0) /* Skip initial filler */ | |
568 sp += 2; | |
569 else /* Skip initial channels and, for sp, the filler */ | |
570 sp += 8, dp += 6; | |
571 | |
572 while (sp < ep) | |
573 { | |
574 /* Copy 6 bytes, skip 2 */ | |
575 *dp++ = *sp++, *dp++ = *sp++; | |
576 *dp++ = *sp++, *dp++ = *sp++; | |
577 *dp++ = *sp++, *dp++ = *sp, sp += 3; | |
578 } | |
579 | |
580 row_info->pixel_depth = 48; | |
581 } | |
582 | |
583 else | |
584 return; /* bad bit depth */ | |
585 | |
586 row_info->channels = 3; | |
587 | |
588 /* Finally fix the color type if it records an alpha channel */ | |
589 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
590 row_info->color_type = PNG_COLOR_TYPE_RGB; | |
591 } | |
592 | |
593 else | |
594 return; /* The filler channel has gone already */ | |
595 | |
596 /* Fix the rowbytes value. */ | |
597 row_info->rowbytes = dp-row; | |
598 } | |
599 #endif | |
600 | |
601 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) | |
602 /* Swaps red and blue bytes within a pixel */ | |
603 void /* PRIVATE */ | |
604 png_do_bgr(png_row_infop row_info, png_bytep row) | |
605 { | |
606 png_debug(1, "in png_do_bgr"); | |
607 | |
608 if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0) | |
609 { | |
610 png_uint_32 row_width = row_info->width; | |
611 if (row_info->bit_depth == 8) | |
612 { | |
613 if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
614 { | |
615 png_bytep rp; | |
616 png_uint_32 i; | |
617 | |
618 for (i = 0, rp = row; i < row_width; i++, rp += 3) | |
619 { | |
620 png_byte save = *rp; | |
621 *rp = *(rp + 2); | |
622 *(rp + 2) = save; | |
623 } | |
624 } | |
625 | |
626 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
627 { | |
628 png_bytep rp; | |
629 png_uint_32 i; | |
630 | |
631 for (i = 0, rp = row; i < row_width; i++, rp += 4) | |
632 { | |
633 png_byte save = *rp; | |
634 *rp = *(rp + 2); | |
635 *(rp + 2) = save; | |
636 } | |
637 } | |
638 } | |
639 | |
640 #ifdef PNG_16BIT_SUPPORTED | |
641 else if (row_info->bit_depth == 16) | |
642 { | |
643 if (row_info->color_type == PNG_COLOR_TYPE_RGB) | |
644 { | |
645 png_bytep rp; | |
646 png_uint_32 i; | |
647 | |
648 for (i = 0, rp = row; i < row_width; i++, rp += 6) | |
649 { | |
650 png_byte save = *rp; | |
651 *rp = *(rp + 4); | |
652 *(rp + 4) = save; | |
653 save = *(rp + 1); | |
654 *(rp + 1) = *(rp + 5); | |
655 *(rp + 5) = save; | |
656 } | |
657 } | |
658 | |
659 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
660 { | |
661 png_bytep rp; | |
662 png_uint_32 i; | |
663 | |
664 for (i = 0, rp = row; i < row_width; i++, rp += 8) | |
665 { | |
666 png_byte save = *rp; | |
667 *rp = *(rp + 4); | |
668 *(rp + 4) = save; | |
669 save = *(rp + 1); | |
670 *(rp + 1) = *(rp + 5); | |
671 *(rp + 5) = save; | |
672 } | |
673 } | |
674 } | |
675 #endif | |
676 } | |
677 } | |
678 #endif /* READ_BGR || WRITE_BGR */ | |
679 | |
680 #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \ | |
681 defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED) | |
682 /* Added at libpng-1.5.10 */ | |
683 void /* PRIVATE */ | |
684 png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info) | |
685 { | |
686 if (png_ptr->num_palette < (1 << row_info->bit_depth) && | |
687 png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */ | |
688 { | |
689 /* Calculations moved outside switch in an attempt to stop different | |
690 * compiler warnings. 'padding' is in *bits* within the last byte, it is | |
691 * an 'int' because pixel_depth becomes an 'int' in the expression below, | |
692 * and this calculation is used because it avoids warnings that other | |
693 * forms produced on either GCC or MSVC. | |
694 */ | |
695 int padding = (-row_info->pixel_depth * row_info->width) & 7; | |
696 png_bytep rp = png_ptr->row_buf + row_info->rowbytes; | |
697 | |
698 switch (row_info->bit_depth) | |
699 { | |
700 case 1: | |
701 { | |
702 /* in this case, all bytes must be 0 so we don't need | |
703 * to unpack the pixels except for the rightmost one. | |
704 */ | |
705 for (; rp > png_ptr->row_buf; rp--) | |
706 { | |
707 if ((*rp >> padding) != 0) | |
708 png_ptr->num_palette_max = 1; | |
709 padding = 0; | |
710 } | |
711 | |
712 break; | |
713 } | |
714 | |
715 case 2: | |
716 { | |
717 for (; rp > png_ptr->row_buf; rp--) | |
718 { | |
719 int i = ((*rp >> padding) & 0x03); | |
720 | |
721 if (i > png_ptr->num_palette_max) | |
722 png_ptr->num_palette_max = i; | |
723 | |
724 i = (((*rp >> padding) >> 2) & 0x03); | |
725 | |
726 if (i > png_ptr->num_palette_max) | |
727 png_ptr->num_palette_max = i; | |
728 | |
729 i = (((*rp >> padding) >> 4) & 0x03); | |
730 | |
731 if (i > png_ptr->num_palette_max) | |
732 png_ptr->num_palette_max = i; | |
733 | |
734 i = (((*rp >> padding) >> 6) & 0x03); | |
735 | |
736 if (i > png_ptr->num_palette_max) | |
737 png_ptr->num_palette_max = i; | |
738 | |
739 padding = 0; | |
740 } | |
741 | |
742 break; | |
743 } | |
744 | |
745 case 4: | |
746 { | |
747 for (; rp > png_ptr->row_buf; rp--) | |
748 { | |
749 int i = ((*rp >> padding) & 0x0f); | |
750 | |
751 if (i > png_ptr->num_palette_max) | |
752 png_ptr->num_palette_max = i; | |
753 | |
754 i = (((*rp >> padding) >> 4) & 0x0f); | |
755 | |
756 if (i > png_ptr->num_palette_max) | |
757 png_ptr->num_palette_max = i; | |
758 | |
759 padding = 0; | |
760 } | |
761 | |
762 break; | |
763 } | |
764 | |
765 case 8: | |
766 { | |
767 for (; rp > png_ptr->row_buf; rp--) | |
768 { | |
769 if (*rp > png_ptr->num_palette_max) | |
770 png_ptr->num_palette_max = (int) *rp; | |
771 } | |
772 | |
773 break; | |
774 } | |
775 | |
776 default: | |
777 break; | |
778 } | |
779 } | |
780 } | |
781 #endif /* CHECK_FOR_INVALID_INDEX */ | |
782 | |
783 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ | |
784 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) | |
785 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED | |
786 void PNGAPI | |
787 png_set_user_transform_info(png_structrp png_ptr, png_voidp | |
788 user_transform_ptr, int user_transform_depth, int user_transform_channels) | |
789 { | |
790 png_debug(1, "in png_set_user_transform_info"); | |
791 | |
792 if (png_ptr == NULL) | |
793 return; | |
794 | |
795 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED | |
796 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
797 (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0) | |
798 { | |
799 png_app_error(png_ptr, | |
800 "info change after png_start_read_image or png_read_update_info"); | |
801 return; | |
802 } | |
803 #endif | |
804 | |
805 png_ptr->user_transform_ptr = user_transform_ptr; | |
806 png_ptr->user_transform_depth = (png_byte)user_transform_depth; | |
807 png_ptr->user_transform_channels = (png_byte)user_transform_channels; | |
808 } | |
809 #endif | |
810 | |
811 /* This function returns a pointer to the user_transform_ptr associated with | |
812 * the user transform functions. The application should free any memory | |
813 * associated with this pointer before png_write_destroy and png_read_destroy | |
814 * are called. | |
815 */ | |
816 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED | |
817 png_voidp PNGAPI | |
818 png_get_user_transform_ptr(png_const_structrp png_ptr) | |
819 { | |
820 if (png_ptr == NULL) | |
821 return (NULL); | |
822 | |
823 return png_ptr->user_transform_ptr; | |
824 } | |
825 #endif | |
826 | |
827 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED | |
828 png_uint_32 PNGAPI | |
829 png_get_current_row_number(png_const_structrp png_ptr) | |
830 { | |
831 /* See the comments in png.h - this is the sub-image row when reading an | |
832 * interlaced image. | |
833 */ | |
834 if (png_ptr != NULL) | |
835 return png_ptr->row_number; | |
836 | |
837 return PNG_UINT_32_MAX; /* help the app not to fail silently */ | |
838 } | |
839 | |
840 png_byte PNGAPI | |
841 png_get_current_pass_number(png_const_structrp png_ptr) | |
842 { | |
843 if (png_ptr != NULL) | |
844 return png_ptr->pass; | |
845 return 8; /* invalid */ | |
846 } | |
847 #endif /* USER_TRANSFORM_INFO */ | |
848 #endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */ | |
849 #endif /* READ || WRITE */ | |
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