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b59bf2db JS |
1 | ///////////////////////////////////////////////////////////////////////////// |
2 | // Name: imaggif.cpp | |
3 | // Purpose: wxGIFHandler | |
4 | // Author: Guillermo Rodriguez Garcia | |
5 | // wxWindows adaptation by Vaclav Slavik | |
6 | // Licence: wxWindows licence | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
ce4169a4 RR |
9 | /* |
10 | We don't put pragma implement in this file because it is already present in | |
11 | src/common/image.cpp | |
12 | */ | |
b59bf2db JS |
13 | |
14 | // For compilers that support precompilation, includes "wx.h". | |
15 | #include <wx/wxprec.h> | |
16 | ||
17 | #ifdef __BORLANDC__ | |
ce4169a4 | 18 | #pragma hdrstop |
b59bf2db JS |
19 | #endif |
20 | ||
ce4169a4 RR |
21 | #ifndef WX_PRECOMP |
22 | #include "wx/defs.h" | |
23 | #endif | |
b59bf2db | 24 | |
ce4169a4 RR |
25 | #include "wx/image.h" |
26 | #include "wx/wfstream.h" | |
27 | #include "wx/module.h" | |
28 | #include "wx/log.h" | |
b59bf2db | 29 | |
ce4169a4 RR |
30 | IMPLEMENT_DYNAMIC_CLASS(wxGIFHandler,wxImageHandler) |
31 | ||
32 | #if wxUSE_STREAMS | |
b59bf2db JS |
33 | |
34 | /* | |
35 | ||
36 | FOLLOWING CODE IS BY G.R.G. : | |
37 | (except wxInputStream stuff) | |
38 | ||
39 | */ | |
40 | ||
41 | /************************************************************************ | |
e207152c | 42 | READGIF.H - Reads a GIF file |
b59bf2db JS |
43 | ------------------------------------------------------------------------ |
44 | Guillermo Rodriguez Garcia | |
45 | <guille@iies.es> | |
46 | ||
99cc0158 | 47 | Version: 2.1 |
b59bf2db JS |
48 | *************************************************************************/ |
49 | ||
e207152c | 50 | |
b59bf2db JS |
51 | typedef struct |
52 | { | |
53 | int w; /* width */ | |
54 | int h; /* height */ | |
99cc0158 | 55 | int transparent; /* transparent color (-1 = none) */ |
b59bf2db JS |
56 | unsigned char *p; /* bitmap */ |
57 | unsigned char *pal; /* palette */ | |
58 | } IMAGEN; | |
59 | ||
60 | ||
e207152c | 61 | |
b59bf2db | 62 | /************************************************************************ |
e207152c | 63 | READGIF.C - Reads a GIF file |
b59bf2db JS |
64 | ------------------------------------------------------------------------ |
65 | Guillermo Rodriguez Garcia | |
66 | <guille@iies.es> | |
67 | ||
99cc0158 | 68 | Version: 2.1 |
b59bf2db JS |
69 | *************************************************************************/ |
70 | ||
71 | ||
b59bf2db JS |
72 | #include <stdlib.h> |
73 | #include <string.h> | |
74 | ||
75 | ||
76 | /* error codes */ | |
77 | #define E_OK 0 /* everything was OK */ | |
78 | #define E_ARCHIVO -1 /* error opening file */ | |
79 | #define E_FORMATO -2 /* error in gif header */ | |
80 | #define E_MEMORIA -3 /* error allocating memory */ | |
81 | ||
82 | ||
83 | /* This class binding is by VS, so all bugs in it are mine ;-) */ | |
84 | ||
85 | class gifDecoder | |
86 | { | |
87 | private: | |
88 | /* globals */ | |
89 | int restbits; /* remaining valid bits */ | |
90 | unsigned int restbyte; /* remaining bytes in this block */ | |
91 | unsigned int lastbyte; /* last byte read */ | |
92 | ||
53b7ce7e | 93 | wxInputStream *f; /* input file */ |
b59bf2db | 94 | |
e207152c VS |
95 | public: |
96 | gifDecoder(wxInputStream *s) { f = s; } | |
97 | int getcode(int bits); | |
98 | int dgif(IMAGEN *img, int interl, int bits); | |
99 | int readgif(IMAGEN *img); | |
b59bf2db JS |
100 | }; |
101 | ||
102 | ||
b59bf2db JS |
103 | |
104 | /* getcode: | |
105 | * Reads the next code from the file, with size 'bits' | |
b59bf2db JS |
106 | */ |
107 | int gifDecoder::getcode(int bits) | |
108 | { | |
109 | unsigned int mask; /* bit mask */ | |
110 | unsigned int code; /* code (result) */ | |
111 | ||
112 | ||
113 | /* get remaining bits from last byte read */ | |
114 | mask = (1 << bits) - 1; | |
115 | code = (lastbyte >> (8 - restbits)) & mask; | |
116 | ||
e207152c | 117 | /* keep reading new bytes while needed */ |
b59bf2db JS |
118 | while (bits > restbits) |
119 | { | |
120 | /* if no bytes left in this block, read the next block */ | |
121 | if (restbyte == 0) | |
e207152c | 122 | restbyte = (unsigned char)f->GetC(); |
b59bf2db JS |
123 | |
124 | /* read next byte and isolate the bits we need */ | |
e207152c | 125 | lastbyte = (unsigned char)f->GetC(); |
b59bf2db JS |
126 | mask = (1 << (bits - restbits)) - 1; |
127 | code = code + ((lastbyte & mask) << restbits); | |
128 | restbyte--; | |
129 | ||
130 | /* adjust total number of bits extracted from the buffer */ | |
131 | restbits = restbits + 8; | |
132 | } | |
e207152c | 133 | |
b59bf2db JS |
134 | /* find number of bits reamining for next code */ |
135 | restbits = (restbits - bits); | |
136 | ||
137 | return code; | |
138 | } | |
139 | ||
53b7ce7e | 140 | |
e207152c | 141 | |
b59bf2db JS |
142 | /* dgif: |
143 | * GIF decoding function. The initial code size (aka root size) | |
144 | * is 'bits'. Supports interlaced images (interl == 1). | |
145 | */ | |
146 | int gifDecoder::dgif(IMAGEN *img, int interl, int bits) | |
147 | { | |
148 | int ab_prefix[4096]; /* alphabet (prefixes) */ | |
149 | int ab_tail[4096]; /* alphabet (tails) */ | |
150 | int stack[4096]; /* decompression stack */ | |
151 | ||
152 | int ab_clr; /* clear code */ | |
153 | int ab_fin; /* end of info code */ | |
154 | int ab_bits; /* actual symbol width, in bits */ | |
155 | int ab_free; /* first free position in alphabet */ | |
156 | int ab_max; /* last possible character in alphabet */ | |
157 | int pass; /* pass number in interlaced images */ | |
158 | int pos; /* index into decompresion stack */ | |
159 | int x, y; /* position in image buffer */ | |
160 | ||
161 | int code, readcode, lastcode, abcabca; | |
162 | ||
163 | /* these won't change */ | |
164 | ab_clr = (1 << bits); | |
165 | ab_fin = (1 << bits) + 1; | |
166 | ||
167 | /* these will change through the decompression proccess */ | |
168 | ab_bits = bits + 1; | |
169 | ab_free = (1 << bits) + 2; | |
170 | ab_max = (1 << ab_bits) - 1; | |
171 | lastcode = -1; | |
172 | abcabca = -1; | |
173 | pass = 1; | |
174 | pos = x = y = 0; | |
175 | ||
176 | /* reset static globals */ | |
177 | restbits = 0; | |
178 | restbyte = 0; | |
179 | lastbyte = 0; | |
180 | ||
181 | do | |
182 | { | |
183 | /* get next code */ | |
184 | readcode = code = getcode(ab_bits); | |
185 | ||
186 | /* end of image? */ | |
187 | if (code == ab_fin) break; | |
188 | ||
189 | /* reset alphabet? */ | |
190 | if (code == ab_clr) | |
191 | { | |
192 | /* reset main variables */ | |
193 | ab_bits = bits + 1; | |
194 | ab_free = (1 << bits) + 2; | |
195 | ab_max = (1 << ab_bits) - 1; | |
196 | lastcode = -1; | |
197 | abcabca = -1; | |
198 | ||
199 | /* skip to next code */ | |
200 | continue; | |
201 | } | |
202 | ||
203 | /* unknown code: special case (like in ABCABCA) */ | |
204 | if (code >= ab_free) | |
205 | { | |
206 | code = lastcode; /* take last string */ | |
207 | stack[pos++] = abcabca; /* add first character */ | |
208 | } | |
209 | ||
210 | /* build the string for this code in the stack */ | |
211 | while (code > ab_clr) | |
212 | { | |
213 | stack[pos++] = ab_tail[code]; | |
214 | code = ab_prefix[code]; | |
215 | } | |
216 | stack[pos] = code; /* push last code into the stack */ | |
217 | abcabca = code; /* save for special case */ | |
218 | ||
219 | /* make new entry in alphabet (only if NOT just cleared) */ | |
220 | if (lastcode != -1) | |
221 | { | |
222 | ab_prefix[ab_free] = lastcode; | |
223 | ab_tail[ab_free] = code; | |
224 | ab_free++; | |
225 | ||
226 | if ((ab_free > ab_max) && (ab_bits < 12)) | |
227 | { | |
228 | ab_bits++; | |
229 | ab_max = (1 << ab_bits) - 1; | |
230 | } | |
231 | } | |
232 | ||
233 | /* dump stack data to the buffer */ | |
234 | while (pos >= 0) | |
235 | { | |
236 | (img->p)[x + (y * (img->w))] = (char)stack[pos--]; | |
237 | ||
238 | if (++x >= (img->w)) | |
239 | { | |
240 | x = 0; | |
241 | ||
242 | if (interl) | |
243 | { | |
244 | /* support for interlaced images */ | |
245 | switch (pass) | |
246 | { | |
247 | case 1: y += 8; break; | |
248 | case 2: y += 8; break; | |
249 | case 3: y += 4; break; | |
250 | case 4: y += 2; break; | |
251 | } | |
252 | if (y >= (img->h)) | |
253 | { | |
254 | switch (++pass) | |
255 | { | |
256 | case 2: y = 4; break; | |
257 | case 3: y = 2; break; | |
258 | case 4: y = 1; break; | |
259 | } | |
260 | } | |
261 | } | |
262 | else | |
263 | { | |
264 | /* non-interlaced */ | |
265 | y++; | |
266 | } | |
267 | } | |
268 | } | |
269 | ||
270 | pos = 0; | |
271 | lastcode = readcode; | |
272 | } | |
273 | while (code != ab_fin); | |
274 | ||
275 | return 0; | |
276 | } | |
277 | ||
e207152c VS |
278 | |
279 | ||
b59bf2db JS |
280 | /* readgif: |
281 | * Reads a GIF image from the file with filename 'nombre' in the | |
282 | * IMAGEN structure pointed by 'img'. Can read GIFs with any bit | |
283 | * size (color depth), but the output image is always expanded | |
284 | * to 8 bits per pixel. Also, the image palette always contains | |
285 | * 256 colors, although some of them may be unused. Returns E_OK | |
286 | * (== 0) on success, or an error code if something fails. Error | |
287 | * codes are E_ARCHIVO, E_FORMATO, E_MEMORIA (see above). | |
288 | */ | |
289 | int gifDecoder::readgif(IMAGEN *img) | |
290 | { | |
291 | int size, ncolors, bits, interl, i; | |
292 | unsigned char pal[768]; | |
293 | unsigned char buf[16]; | |
294 | ||
e207152c | 295 | |
b59bf2db | 296 | /* read header and logical screen descriptor block (LSDB) */ |
e207152c | 297 | f->Read(buf, 13); |
b59bf2db JS |
298 | |
299 | /* check GIF signature */ | |
300 | if (memcmp(buf, "GIF", 3) != 0) return E_FORMATO; | |
301 | ||
302 | /* load global color map if available */ | |
303 | if ((buf[10] & 0x80) == 0x80) | |
304 | { | |
305 | ncolors = 2 << (buf[10] & 0x07); | |
e207152c | 306 | f->Read(pal, 3 * ncolors); |
b59bf2db JS |
307 | } |
308 | ||
99cc0158 VS |
309 | /* assume no transparent color */ |
310 | img->transparent = -1; | |
b59bf2db | 311 | |
99cc0158 | 312 | /* skip most extensions */ |
e207152c | 313 | while (((unsigned char)f->GetC()) == 0x21) /* separator */ |
99cc0158 | 314 | { |
e207152c | 315 | if (((unsigned char)f->GetC()) == 0xF9) /* graphic control ext. */ |
99cc0158 | 316 | { |
99cc0158 | 317 | f->Read(buf, 6); |
e207152c | 318 | if (buf[1] & 0x01) |
99cc0158 | 319 | img->transparent = buf[4]; |
99cc0158 VS |
320 | } |
321 | else | |
e207152c | 322 | while ((i = (unsigned char)f->GetC()) != 0) /* byte count */ |
99cc0158 | 323 | f->SeekI(i, wxFromCurrent); |
b59bf2db JS |
324 | } |
325 | ||
326 | /* read image descriptor block (IDB) */ | |
e207152c | 327 | f->Read(buf, 9); |
b59bf2db | 328 | img->w = buf[4] + 256 * buf[5]; |
b59bf2db JS |
329 | img->h = buf[6] + 256 * buf[7]; |
330 | size = img->w * img->h; | |
331 | interl = ((buf[8] & 0x40)? 1 : 0); | |
332 | ||
333 | /* load local color map if available */ | |
334 | if ((buf[8] & 0x80) == 0x80) | |
335 | { | |
336 | ncolors = 2 << (buf[8] & 0x07); | |
e207152c | 337 | f->Read(pal, 3 * ncolors); |
b59bf2db JS |
338 | } |
339 | ||
340 | /* get initial code size from first byte in raster data */ | |
e207152c | 341 | bits = (unsigned char)f->GetC(); |
b59bf2db JS |
342 | |
343 | /* allocate memory for image and palette */ | |
344 | if ((img->p = (unsigned char*) malloc(size)) == NULL) return E_MEMORIA; | |
345 | if ((img->pal = (unsigned char*) malloc(768)) == NULL) return E_MEMORIA; | |
346 | ||
347 | /* shift palette to fit VGA 6-bit format */ | |
348 | for (i = 0; i < 768; i++) | |
e207152c | 349 | (img->pal)[i] = (unsigned char)pal[i]; /* >> 2 not in wxWin */ |
b59bf2db JS |
350 | |
351 | /* decode GIF */ | |
352 | dgif(img, interl, bits); | |
353 | ||
354 | /* finish successfully :-) */ | |
355 | return E_OK; | |
356 | } | |
357 | ||
e207152c VS |
358 | |
359 | ||
b59bf2db JS |
360 | /* |
361 | ||
362 | FOLLOWING CODE IS BY V.S. : | |
363 | ||
364 | */ | |
365 | ||
366 | //----------------------------------------------------------------------------- | |
367 | // wxGIFHandler | |
368 | //----------------------------------------------------------------------------- | |
369 | ||
b59bf2db JS |
370 | bool wxGIFHandler::LoadFile( wxImage *image, wxInputStream& stream ) |
371 | { | |
372 | unsigned char *ptr, *src, *pal; | |
b59bf2db JS |
373 | IMAGEN igif; |
374 | int i; | |
375 | gifDecoder *decod; | |
376 | ||
377 | image->Destroy(); | |
378 | ||
53b7ce7e | 379 | decod = new gifDecoder(&stream); |
b59bf2db | 380 | |
e207152c | 381 | if (decod->readgif(&igif) != E_OK) { |
3e473156 | 382 | wxLogDebug(_T("Error reading GIF")); |
b59bf2db JS |
383 | delete decod; |
384 | return FALSE; | |
385 | } | |
b59bf2db JS |
386 | delete decod; |
387 | ||
388 | image->Create(igif.w, igif.h); | |
389 | if (!image->Ok()) { | |
390 | free(igif.pal); | |
391 | free(igif.p); | |
392 | return FALSE; | |
393 | } | |
b59bf2db JS |
394 | |
395 | ptr = image->GetData(); | |
396 | src = igif.p; | |
397 | pal = igif.pal; | |
e207152c VS |
398 | |
399 | if (igif.transparent != -1) { | |
400 | for (i = 0; i < 256; i++) | |
401 | if ((pal[3 * i + 0] == 255) && (pal[3 * i + 1] == 0) && (pal[3 * i + 2] == 255)) pal[3 * i + 2] = 254; | |
402 | pal[3 * (igif.transparent) + 0] = 255, | |
403 | pal[3 * (igif.transparent) + 1] = 0, | |
404 | pal[3 * (igif.transparent) + 2] = 255; | |
405 | image->SetMaskColour(255, 0, 255); | |
406 | } | |
407 | else image->SetMask(FALSE); | |
408 | ||
b59bf2db JS |
409 | for (i = 0; i < igif.w * igif.h; i++, src++) { |
410 | *(ptr++) = pal[3 * (*src) + 0]; | |
411 | *(ptr++) = pal[3 * (*src) + 1]; | |
412 | *(ptr++) = pal[3 * (*src) + 2]; | |
413 | } | |
414 | ||
415 | free(igif.pal); | |
416 | free(igif.p); | |
417 | return TRUE; | |
418 | } | |
419 | ||
74e3313b VZ |
420 | bool wxGIFHandler::SaveFile( wxImage * WXUNUSED(image), |
421 | wxOutputStream& WXUNUSED(stream) ) | |
b59bf2db | 422 | { |
3e473156 | 423 | wxLogDebug(_T("wxGIFHandler is read-only!!")); |
b59bf2db JS |
424 | return FALSE; |
425 | } | |
426 | ||
ce4169a4 | 427 | #endif |