1 :
2 : /* pngtrans.c - transforms the data in a row (used by both readers and writers)
3 : *
4 : * Last changed in libpng 1.5.4 [July 7, 2011]
5 : * Copyright (c) 1998-2011 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_structp 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_structp 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_structp 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 : png_ptr->usr_bit_depth = 8;
61 : }
62 : }
63 : #endif
64 :
65 : #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
66 : /* Turn on packed pixel swapping */
67 : void PNGAPI
68 : png_set_packswap(png_structp png_ptr)
69 : {
70 : png_debug(1, "in png_set_packswap");
71 :
72 : if (png_ptr == NULL)
73 : return;
74 :
75 : if (png_ptr->bit_depth < 8)
76 : png_ptr->transformations |= PNG_PACKSWAP;
77 : }
78 : #endif
79 :
80 : #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
81 : void PNGAPI
82 : png_set_shift(png_structp png_ptr, png_const_color_8p true_bits)
83 : {
84 : png_debug(1, "in png_set_shift");
85 :
86 : if (png_ptr == NULL)
87 : return;
88 :
89 : png_ptr->transformations |= PNG_SHIFT;
90 : png_ptr->shift = *true_bits;
91 : }
92 : #endif
93 :
94 : #if defined(PNG_READ_INTERLACING_SUPPORTED) || \
95 : defined(PNG_WRITE_INTERLACING_SUPPORTED)
96 : int PNGAPI
97 0 : png_set_interlace_handling(png_structp png_ptr)
98 : {
99 : png_debug(1, "in png_set_interlace handling");
100 :
101 0 : if (png_ptr && png_ptr->interlaced)
102 : {
103 0 : png_ptr->transformations |= PNG_INTERLACE;
104 0 : return (7);
105 : }
106 :
107 0 : return (1);
108 : }
109 : #endif
110 :
111 : #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
112 : /* Add a filler byte on read, or remove a filler or alpha byte on write.
113 : * The filler type has changed in v0.95 to allow future 2-byte fillers
114 : * for 48-bit input data, as well as to avoid problems with some compilers
115 : * that don't like bytes as parameters.
116 : */
117 : void PNGAPI
118 : png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
119 : {
120 : png_debug(1, "in png_set_filler");
121 :
122 : if (png_ptr == NULL)
123 : return;
124 :
125 : png_ptr->transformations |= PNG_FILLER;
126 : png_ptr->filler = (png_uint_16)filler;
127 :
128 : if (filler_loc == PNG_FILLER_AFTER)
129 : png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
130 :
131 : else
132 : png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
133 :
134 : /* This should probably go in the "do_read_filler" routine.
135 : * I attempted to do that in libpng-1.0.1a but that caused problems
136 : * so I restored it in libpng-1.0.2a
137 : */
138 :
139 : if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
140 : {
141 : png_ptr->usr_channels = 4;
142 : }
143 :
144 : /* Also I added this in libpng-1.0.2a (what happens when we expand
145 : * a less-than-8-bit grayscale to GA?) */
146 :
147 : if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth >= 8)
148 : {
149 : png_ptr->usr_channels = 2;
150 : }
151 : }
152 :
153 : /* Added to libpng-1.2.7 */
154 : void PNGAPI
155 : png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
156 : {
157 : png_debug(1, "in png_set_add_alpha");
158 :
159 : if (png_ptr == NULL)
160 : return;
161 :
162 : png_set_filler(png_ptr, filler, filler_loc);
163 : png_ptr->transformations |= PNG_ADD_ALPHA;
164 : }
165 :
166 : #endif
167 :
168 : #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
169 : defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
170 : void PNGAPI
171 : png_set_swap_alpha(png_structp png_ptr)
172 : {
173 : png_debug(1, "in png_set_swap_alpha");
174 :
175 : if (png_ptr == NULL)
176 : return;
177 :
178 : png_ptr->transformations |= PNG_SWAP_ALPHA;
179 : }
180 : #endif
181 :
182 : #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
183 : defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
184 : void PNGAPI
185 : png_set_invert_alpha(png_structp png_ptr)
186 : {
187 : png_debug(1, "in png_set_invert_alpha");
188 :
189 : if (png_ptr == NULL)
190 : return;
191 :
192 : png_ptr->transformations |= PNG_INVERT_ALPHA;
193 : }
194 : #endif
195 :
196 : #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
197 : void PNGAPI
198 : png_set_invert_mono(png_structp png_ptr)
199 : {
200 : png_debug(1, "in png_set_invert_mono");
201 :
202 : if (png_ptr == NULL)
203 : return;
204 :
205 : png_ptr->transformations |= PNG_INVERT_MONO;
206 : }
207 :
208 : /* Invert monochrome grayscale data */
209 : void /* PRIVATE */
210 : png_do_invert(png_row_infop row_info, png_bytep row)
211 : {
212 : png_debug(1, "in png_do_invert");
213 :
214 : /* This test removed from libpng version 1.0.13 and 1.2.0:
215 : * if (row_info->bit_depth == 1 &&
216 : */
217 : if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
218 : {
219 : png_bytep rp = row;
220 : png_size_t i;
221 : png_size_t istop = row_info->rowbytes;
222 :
223 : for (i = 0; i < istop; i++)
224 : {
225 : *rp = (png_byte)(~(*rp));
226 : rp++;
227 : }
228 : }
229 :
230 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
231 : row_info->bit_depth == 8)
232 : {
233 : png_bytep rp = row;
234 : png_size_t i;
235 : png_size_t istop = row_info->rowbytes;
236 :
237 : for (i = 0; i < istop; i += 2)
238 : {
239 : *rp = (png_byte)(~(*rp));
240 : rp += 2;
241 : }
242 : }
243 :
244 : #ifdef PNG_16BIT_SUPPORTED
245 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
246 : row_info->bit_depth == 16)
247 : {
248 : png_bytep rp = row;
249 : png_size_t i;
250 : png_size_t istop = row_info->rowbytes;
251 :
252 : for (i = 0; i < istop; i += 4)
253 : {
254 : *rp = (png_byte)(~(*rp));
255 : *(rp + 1) = (png_byte)(~(*(rp + 1)));
256 : rp += 4;
257 : }
258 : }
259 : #endif
260 : }
261 : #endif
262 :
263 : #ifdef PNG_16BIT_SUPPORTED
264 : #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
265 : /* Swaps byte order on 16 bit depth images */
266 : void /* PRIVATE */
267 : png_do_swap(png_row_infop row_info, png_bytep row)
268 : {
269 : png_debug(1, "in png_do_swap");
270 :
271 : if (row_info->bit_depth == 16)
272 : {
273 : png_bytep rp = row;
274 : png_uint_32 i;
275 : png_uint_32 istop= row_info->width * row_info->channels;
276 :
277 : for (i = 0; i < istop; i++, rp += 2)
278 : {
279 : png_byte t = *rp;
280 : *rp = *(rp + 1);
281 : *(rp + 1) = t;
282 : }
283 : }
284 : }
285 : #endif
286 : #endif
287 :
288 : #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
289 : static PNG_CONST png_byte onebppswaptable[256] = {
290 : 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
291 : 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
292 : 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
293 : 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
294 : 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
295 : 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
296 : 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
297 : 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
298 : 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
299 : 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
300 : 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
301 : 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
302 : 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
303 : 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
304 : 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
305 : 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
306 : 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
307 : 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
308 : 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
309 : 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
310 : 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
311 : 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
312 : 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
313 : 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
314 : 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
315 : 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
316 : 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
317 : 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
318 : 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
319 : 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
320 : 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
321 : 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
322 : };
323 :
324 : static PNG_CONST png_byte twobppswaptable[256] = {
325 : 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
326 : 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
327 : 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
328 : 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
329 : 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
330 : 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
331 : 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
332 : 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
333 : 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
334 : 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
335 : 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
336 : 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
337 : 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
338 : 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
339 : 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
340 : 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
341 : 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
342 : 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
343 : 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
344 : 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
345 : 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
346 : 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
347 : 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
348 : 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
349 : 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
350 : 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
351 : 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
352 : 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
353 : 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
354 : 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
355 : 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
356 : 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
357 : };
358 :
359 : static PNG_CONST png_byte fourbppswaptable[256] = {
360 : 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
361 : 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
362 : 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
363 : 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
364 : 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
365 : 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
366 : 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
367 : 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
368 : 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
369 : 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
370 : 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
371 : 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
372 : 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
373 : 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
374 : 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
375 : 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
376 : 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
377 : 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
378 : 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
379 : 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
380 : 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
381 : 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
382 : 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
383 : 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
384 : 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
385 : 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
386 : 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
387 : 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
388 : 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
389 : 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
390 : 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
391 : 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
392 : };
393 :
394 : /* Swaps pixel packing order within bytes */
395 : void /* PRIVATE */
396 : png_do_packswap(png_row_infop row_info, png_bytep row)
397 : {
398 : png_debug(1, "in png_do_packswap");
399 :
400 : if (row_info->bit_depth < 8)
401 : {
402 : png_bytep rp;
403 : png_const_bytep end, table;
404 :
405 : end = row + row_info->rowbytes;
406 :
407 : if (row_info->bit_depth == 1)
408 : table = onebppswaptable;
409 :
410 : else if (row_info->bit_depth == 2)
411 : table = twobppswaptable;
412 :
413 : else if (row_info->bit_depth == 4)
414 : table = fourbppswaptable;
415 :
416 : else
417 : return;
418 :
419 : for (rp = row; rp < end; rp++)
420 : *rp = table[*rp];
421 : }
422 : }
423 : #endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
424 :
425 : #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
426 : defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
427 : /* Remove a channel - this used to be 'png_do_strip_filler' but it used a
428 : * somewhat weird combination of flags to determine what to do. All the calls
429 : * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
430 : * correct arguments.
431 : *
432 : * The routine isn't general - the channel must be the channel at the start or
433 : * end (not in the middle) of each pixel.
434 : */
435 : void /* PRIVATE */
436 : png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
437 : {
438 : png_bytep sp = row; /* source pointer */
439 : png_bytep dp = row; /* destination pointer */
440 : png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
441 :
442 : /* At the start sp will point to the first byte to copy and dp to where
443 : * it is copied to. ep always points just beyond the end of the row, so
444 : * the loop simply copies (channels-1) channels until sp reaches ep.
445 : *
446 : * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
447 : * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
448 : */
449 :
450 : /* GA, GX, XG cases */
451 : if (row_info->channels == 2)
452 : {
453 : if (row_info->bit_depth == 8)
454 : {
455 : if (at_start) /* Skip initial filler */
456 : ++sp;
457 : else /* Skip initial channel and, for sp, the filler */
458 : sp += 2, ++dp;
459 :
460 : /* For a 1 pixel wide image there is nothing to do */
461 : while (sp < ep)
462 : *dp++ = *sp, sp += 2;
463 :
464 : row_info->pixel_depth = 8;
465 : }
466 :
467 : else if (row_info->bit_depth == 16)
468 : {
469 : if (at_start) /* Skip initial filler */
470 : sp += 2;
471 : else /* Skip initial channel and, for sp, the filler */
472 : sp += 4, dp += 2;
473 :
474 : while (sp < ep)
475 : *dp++ = *sp++, *dp++ = *sp, sp += 3;
476 :
477 : row_info->pixel_depth = 16;
478 : }
479 :
480 : else
481 : return; /* bad bit depth */
482 :
483 : row_info->channels = 1;
484 :
485 : /* Finally fix the color type if it records an alpha channel */
486 : if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
487 : row_info->color_type = PNG_COLOR_TYPE_GRAY;
488 : }
489 :
490 : /* RGBA, RGBX, XRGB cases */
491 : else if (row_info->channels == 4)
492 : {
493 : if (row_info->bit_depth == 8)
494 : {
495 : if (at_start) /* Skip initial filler */
496 : ++sp;
497 : else /* Skip initial channels and, for sp, the filler */
498 : sp += 4, dp += 3;
499 :
500 : /* Note that the loop adds 3 to dp and 4 to sp each time. */
501 : while (sp < ep)
502 : *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2;
503 :
504 : row_info->pixel_depth = 24;
505 : }
506 :
507 : else if (row_info->bit_depth == 16)
508 : {
509 : if (at_start) /* Skip initial filler */
510 : sp += 2;
511 : else /* Skip initial channels and, for sp, the filler */
512 : sp += 8, dp += 6;
513 :
514 : while (sp < ep)
515 : {
516 : /* Copy 6 bytes, skip 2 */
517 : *dp++ = *sp++, *dp++ = *sp++;
518 : *dp++ = *sp++, *dp++ = *sp++;
519 : *dp++ = *sp++, *dp++ = *sp, sp += 3;
520 : }
521 :
522 : row_info->pixel_depth = 48;
523 : }
524 :
525 : else
526 : return; /* bad bit depth */
527 :
528 : row_info->channels = 3;
529 :
530 : /* Finally fix the color type if it records an alpha channel */
531 : if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
532 : row_info->color_type = PNG_COLOR_TYPE_RGB;
533 : }
534 :
535 : else
536 : return; /* The filler channel has gone already */
537 :
538 : /* Fix the rowbytes value. */
539 : row_info->rowbytes = dp-row;
540 : }
541 : #endif
542 :
543 : #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
544 : /* Swaps red and blue bytes within a pixel */
545 : void /* PRIVATE */
546 : png_do_bgr(png_row_infop row_info, png_bytep row)
547 : {
548 : png_debug(1, "in png_do_bgr");
549 :
550 : if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
551 : {
552 : png_uint_32 row_width = row_info->width;
553 : if (row_info->bit_depth == 8)
554 : {
555 : if (row_info->color_type == PNG_COLOR_TYPE_RGB)
556 : {
557 : png_bytep rp;
558 : png_uint_32 i;
559 :
560 : for (i = 0, rp = row; i < row_width; i++, rp += 3)
561 : {
562 : png_byte save = *rp;
563 : *rp = *(rp + 2);
564 : *(rp + 2) = save;
565 : }
566 : }
567 :
568 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
569 : {
570 : png_bytep rp;
571 : png_uint_32 i;
572 :
573 : for (i = 0, rp = row; i < row_width; i++, rp += 4)
574 : {
575 : png_byte save = *rp;
576 : *rp = *(rp + 2);
577 : *(rp + 2) = save;
578 : }
579 : }
580 : }
581 :
582 : #ifdef PNG_16BIT_SUPPORTED
583 : else if (row_info->bit_depth == 16)
584 : {
585 : if (row_info->color_type == PNG_COLOR_TYPE_RGB)
586 : {
587 : png_bytep rp;
588 : png_uint_32 i;
589 :
590 : for (i = 0, rp = row; i < row_width; i++, rp += 6)
591 : {
592 : png_byte save = *rp;
593 : *rp = *(rp + 4);
594 : *(rp + 4) = save;
595 : save = *(rp + 1);
596 : *(rp + 1) = *(rp + 5);
597 : *(rp + 5) = save;
598 : }
599 : }
600 :
601 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
602 : {
603 : png_bytep rp;
604 : png_uint_32 i;
605 :
606 : for (i = 0, rp = row; i < row_width; i++, rp += 8)
607 : {
608 : png_byte save = *rp;
609 : *rp = *(rp + 4);
610 : *(rp + 4) = save;
611 : save = *(rp + 1);
612 : *(rp + 1) = *(rp + 5);
613 : *(rp + 5) = save;
614 : }
615 : }
616 : }
617 : #endif
618 : }
619 : }
620 : #endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
621 :
622 : #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
623 : defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
624 : #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
625 : void PNGAPI
626 : png_set_user_transform_info(png_structp png_ptr, png_voidp
627 : user_transform_ptr, int user_transform_depth, int user_transform_channels)
628 : {
629 : png_debug(1, "in png_set_user_transform_info");
630 :
631 : if (png_ptr == NULL)
632 : return;
633 : png_ptr->user_transform_ptr = user_transform_ptr;
634 : png_ptr->user_transform_depth = (png_byte)user_transform_depth;
635 : png_ptr->user_transform_channels = (png_byte)user_transform_channels;
636 : }
637 : #endif
638 :
639 : /* This function returns a pointer to the user_transform_ptr associated with
640 : * the user transform functions. The application should free any memory
641 : * associated with this pointer before png_write_destroy and png_read_destroy
642 : * are called.
643 : */
644 : #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
645 : png_voidp PNGAPI
646 : png_get_user_transform_ptr(png_const_structp png_ptr)
647 : {
648 : if (png_ptr == NULL)
649 : return (NULL);
650 :
651 : return ((png_voidp)png_ptr->user_transform_ptr);
652 : }
653 : #endif
654 :
655 : #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
656 : png_uint_32 PNGAPI
657 : png_get_current_row_number(png_const_structp png_ptr)
658 : {
659 : /* See the comments in png.h - this is the sub-image row when reading and
660 : * interlaced image.
661 : */
662 : if (png_ptr != NULL)
663 : return png_ptr->row_number;
664 :
665 : return PNG_UINT_32_MAX; /* help the app not to fail silently */
666 : }
667 :
668 : png_byte PNGAPI
669 : png_get_current_pass_number(png_const_structp png_ptr)
670 : {
671 : if (png_ptr != NULL)
672 : return png_ptr->pass;
673 : return 8; /* invalid */
674 : }
675 : #endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
676 : #endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
677 : PNG_WRITE_USER_TRANSFORM_SUPPORTED */
678 : #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
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