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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 | ||
9 | #ifdef __GNUG__ | |
10 | #pragma implementation "imaggif.h" | |
11 | #endif | |
12 | ||
13 | // For compilers that support precompilation, includes "wx.h". | |
14 | #include <wx/wxprec.h> | |
15 | ||
16 | #ifdef __BORLANDC__ | |
17 | #pragma hdrstop | |
18 | #endif | |
19 | ||
20 | #include <wx/wx.h> | |
21 | ||
22 | #include <wx/image.h> | |
23 | #include <wx/wfstream.h> | |
24 | #include <wx/module.h> | |
25 | ||
26 | #include <wx/imaggif.h> | |
27 | ||
28 | /* | |
29 | ||
30 | FOLLOWING CODE IS BY G.R.G. : | |
31 | (except wxInputStream stuff) | |
32 | ||
33 | */ | |
34 | ||
35 | /************************************************************************ | |
36 | READGIF.H - Leer un archivo GIF de 8 bits | |
37 | ------------------------------------------------------------------------ | |
38 | Tratamiento Digital de la Imagen | |
39 | ------------------------------------------------------------------------ | |
40 | Guillermo Rodriguez Garcia | |
41 | <guille@iies.es> | |
42 | ||
99cc0158 | 43 | Version: 2.1 |
b59bf2db JS |
44 | *************************************************************************/ |
45 | ||
46 | typedef struct | |
47 | { | |
48 | int w; /* width */ | |
49 | int h; /* height */ | |
99cc0158 | 50 | int transparent; /* transparent color (-1 = none) */ |
b59bf2db JS |
51 | unsigned char *p; /* bitmap */ |
52 | unsigned char *pal; /* palette */ | |
53 | } IMAGEN; | |
54 | ||
55 | ||
56 | /************************************************************************ | |
57 | READGIF.C - Lee un archivo GIF de 256 colores | |
58 | ------------------------------------------------------------------------ | |
59 | Tratamiento Digital de la Imagen | |
60 | ------------------------------------------------------------------------ | |
61 | Guillermo Rodriguez Garcia | |
62 | <guille@iies.es> | |
63 | ||
99cc0158 | 64 | Version: 2.1 |
b59bf2db JS |
65 | *************************************************************************/ |
66 | ||
67 | ||
b59bf2db JS |
68 | #include <stdlib.h> |
69 | #include <string.h> | |
70 | ||
71 | ||
72 | /* error codes */ | |
73 | #define E_OK 0 /* everything was OK */ | |
74 | #define E_ARCHIVO -1 /* error opening file */ | |
75 | #define E_FORMATO -2 /* error in gif header */ | |
76 | #define E_MEMORIA -3 /* error allocating memory */ | |
77 | ||
78 | ||
79 | /* This class binding is by VS, so all bugs in it are mine ;-) */ | |
80 | ||
81 | class gifDecoder | |
82 | { | |
83 | private: | |
84 | /* globals */ | |
85 | int restbits; /* remaining valid bits */ | |
86 | unsigned int restbyte; /* remaining bytes in this block */ | |
87 | unsigned int lastbyte; /* last byte read */ | |
88 | ||
53b7ce7e | 89 | wxInputStream *f; /* input file */ |
b59bf2db JS |
90 | |
91 | public: | |
53b7ce7e | 92 | gifDecoder(wxInputStream *s) {f = s;} |
b59bf2db JS |
93 | int getcode(int bits); |
94 | int dgif(IMAGEN *img, int interl, int bits); | |
95 | int readgif(IMAGEN *img); | |
53b7ce7e VS |
96 | |
97 | private: | |
99cc0158 | 98 | unsigned char mygetc(); |
53b7ce7e VS |
99 | // This is NEEDED! GetC is char (signed) why we need unsigned value |
100 | // from here | |
b59bf2db JS |
101 | }; |
102 | ||
103 | ||
99cc0158 VS |
104 | unsigned char gifDecoder::mygetc() |
105 | { | |
106 | unsigned char c; | |
107 | f -> Read(&c, 1); | |
108 | return c; | |
109 | } | |
110 | ||
b59bf2db JS |
111 | |
112 | /* getcode: | |
113 | * Reads the next code from the file, with size 'bits' | |
114 | * v2.0 - changed to support 'bits' values < 8 | |
115 | */ | |
116 | int gifDecoder::getcode(int bits) | |
117 | { | |
118 | unsigned int mask; /* bit mask */ | |
119 | unsigned int code; /* code (result) */ | |
120 | ||
121 | ||
122 | /* get remaining bits from last byte read */ | |
123 | mask = (1 << bits) - 1; | |
124 | code = (lastbyte >> (8 - restbits)) & mask; | |
125 | ||
126 | /* keep reading new bytes until needed */ | |
127 | while (bits > restbits) | |
128 | { | |
129 | /* if no bytes left in this block, read the next block */ | |
130 | if (restbyte == 0) | |
53b7ce7e | 131 | restbyte = mygetc(); |
b59bf2db JS |
132 | |
133 | /* read next byte and isolate the bits we need */ | |
53b7ce7e | 134 | lastbyte = mygetc(); |
b59bf2db JS |
135 | mask = (1 << (bits - restbits)) - 1; |
136 | code = code + ((lastbyte & mask) << restbits); | |
137 | restbyte--; | |
138 | ||
139 | /* adjust total number of bits extracted from the buffer */ | |
140 | restbits = restbits + 8; | |
141 | } | |
142 | ||
143 | /* find number of bits reamining for next code */ | |
144 | restbits = (restbits - bits); | |
145 | ||
146 | return code; | |
147 | } | |
148 | ||
53b7ce7e | 149 | |
b59bf2db JS |
150 | /* dgif: |
151 | * GIF decoding function. The initial code size (aka root size) | |
152 | * is 'bits'. Supports interlaced images (interl == 1). | |
153 | */ | |
154 | int gifDecoder::dgif(IMAGEN *img, int interl, int bits) | |
155 | { | |
156 | int ab_prefix[4096]; /* alphabet (prefixes) */ | |
157 | int ab_tail[4096]; /* alphabet (tails) */ | |
158 | int stack[4096]; /* decompression stack */ | |
159 | ||
160 | int ab_clr; /* clear code */ | |
161 | int ab_fin; /* end of info code */ | |
162 | int ab_bits; /* actual symbol width, in bits */ | |
163 | int ab_free; /* first free position in alphabet */ | |
164 | int ab_max; /* last possible character in alphabet */ | |
165 | int pass; /* pass number in interlaced images */ | |
166 | int pos; /* index into decompresion stack */ | |
167 | int x, y; /* position in image buffer */ | |
168 | ||
169 | int code, readcode, lastcode, abcabca; | |
170 | ||
171 | /* these won't change */ | |
172 | ab_clr = (1 << bits); | |
173 | ab_fin = (1 << bits) + 1; | |
174 | ||
175 | /* these will change through the decompression proccess */ | |
176 | ab_bits = bits + 1; | |
177 | ab_free = (1 << bits) + 2; | |
178 | ab_max = (1 << ab_bits) - 1; | |
179 | lastcode = -1; | |
180 | abcabca = -1; | |
181 | pass = 1; | |
182 | pos = x = y = 0; | |
183 | ||
184 | /* reset static globals */ | |
185 | restbits = 0; | |
186 | restbyte = 0; | |
187 | lastbyte = 0; | |
188 | ||
189 | do | |
190 | { | |
191 | /* get next code */ | |
192 | readcode = code = getcode(ab_bits); | |
193 | ||
194 | /* end of image? */ | |
195 | if (code == ab_fin) break; | |
196 | ||
197 | /* reset alphabet? */ | |
198 | if (code == ab_clr) | |
199 | { | |
200 | /* reset main variables */ | |
201 | ab_bits = bits + 1; | |
202 | ab_free = (1 << bits) + 2; | |
203 | ab_max = (1 << ab_bits) - 1; | |
204 | lastcode = -1; | |
205 | abcabca = -1; | |
206 | ||
207 | /* skip to next code */ | |
208 | continue; | |
209 | } | |
210 | ||
211 | /* unknown code: special case (like in ABCABCA) */ | |
212 | if (code >= ab_free) | |
213 | { | |
214 | code = lastcode; /* take last string */ | |
215 | stack[pos++] = abcabca; /* add first character */ | |
216 | } | |
217 | ||
218 | /* build the string for this code in the stack */ | |
219 | while (code > ab_clr) | |
220 | { | |
221 | stack[pos++] = ab_tail[code]; | |
222 | code = ab_prefix[code]; | |
223 | } | |
224 | stack[pos] = code; /* push last code into the stack */ | |
225 | abcabca = code; /* save for special case */ | |
226 | ||
227 | /* make new entry in alphabet (only if NOT just cleared) */ | |
228 | if (lastcode != -1) | |
229 | { | |
230 | ab_prefix[ab_free] = lastcode; | |
231 | ab_tail[ab_free] = code; | |
232 | ab_free++; | |
233 | ||
234 | if ((ab_free > ab_max) && (ab_bits < 12)) | |
235 | { | |
236 | ab_bits++; | |
237 | ab_max = (1 << ab_bits) - 1; | |
238 | } | |
239 | } | |
240 | ||
241 | /* dump stack data to the buffer */ | |
242 | while (pos >= 0) | |
243 | { | |
244 | (img->p)[x + (y * (img->w))] = (char)stack[pos--]; | |
245 | ||
246 | if (++x >= (img->w)) | |
247 | { | |
248 | x = 0; | |
249 | ||
250 | if (interl) | |
251 | { | |
252 | /* support for interlaced images */ | |
253 | switch (pass) | |
254 | { | |
255 | case 1: y += 8; break; | |
256 | case 2: y += 8; break; | |
257 | case 3: y += 4; break; | |
258 | case 4: y += 2; break; | |
259 | } | |
260 | if (y >= (img->h)) | |
261 | { | |
262 | switch (++pass) | |
263 | { | |
264 | case 2: y = 4; break; | |
265 | case 3: y = 2; break; | |
266 | case 4: y = 1; break; | |
267 | } | |
268 | } | |
269 | } | |
270 | else | |
271 | { | |
272 | /* non-interlaced */ | |
273 | y++; | |
274 | } | |
275 | } | |
276 | } | |
277 | ||
278 | pos = 0; | |
279 | lastcode = readcode; | |
280 | } | |
281 | while (code != ab_fin); | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
286 | /* readgif: | |
287 | * Reads a GIF image from the file with filename 'nombre' in the | |
288 | * IMAGEN structure pointed by 'img'. Can read GIFs with any bit | |
289 | * size (color depth), but the output image is always expanded | |
290 | * to 8 bits per pixel. Also, the image palette always contains | |
291 | * 256 colors, although some of them may be unused. Returns E_OK | |
292 | * (== 0) on success, or an error code if something fails. Error | |
293 | * codes are E_ARCHIVO, E_FORMATO, E_MEMORIA (see above). | |
294 | */ | |
295 | int gifDecoder::readgif(IMAGEN *img) | |
296 | { | |
297 | int size, ncolors, bits, interl, i; | |
298 | unsigned char pal[768]; | |
299 | unsigned char buf[16]; | |
300 | ||
b59bf2db | 301 | /* read header and logical screen descriptor block (LSDB) */ |
53b7ce7e | 302 | f -> Read(buf, 13); |
b59bf2db JS |
303 | |
304 | /* check GIF signature */ | |
305 | if (memcmp(buf, "GIF", 3) != 0) return E_FORMATO; | |
306 | ||
307 | /* load global color map if available */ | |
308 | if ((buf[10] & 0x80) == 0x80) | |
309 | { | |
310 | ncolors = 2 << (buf[10] & 0x07); | |
53b7ce7e | 311 | f -> Read(pal, 3 * ncolors); |
b59bf2db JS |
312 | } |
313 | ||
99cc0158 VS |
314 | /* assume no transparent color */ |
315 | img->transparent = -1; | |
b59bf2db | 316 | |
99cc0158 VS |
317 | /* skip most extensions */ |
318 | while (mygetc() == 0x21) /* separator */ | |
319 | { | |
320 | wxLogDebug("ugh"); | |
321 | if (mygetc() == 0xF9) /* graphic control ext. */ | |
322 | { | |
323 | wxLogDebug("..."); | |
324 | f->Read(buf, 6); | |
325 | wxLogDebug("buf[1] is %i (%i)", buf[1], buf[1] & 0x01); | |
326 | if (buf[1] & 0x01) { | |
327 | wxLogDebug("setting transparen %i", buf[4]); | |
328 | img->transparent = buf[4]; | |
329 | } | |
330 | } | |
331 | else | |
332 | while ((i = mygetc()) != 0) /* byte count */ | |
333 | f->SeekI(i, wxFromCurrent); | |
b59bf2db JS |
334 | } |
335 | ||
336 | /* read image descriptor block (IDB) */ | |
53b7ce7e | 337 | f -> Read(buf, 9); |
b59bf2db JS |
338 | img->w = buf[4] + 256 * buf[5]; |
339 | ||
340 | img->h = buf[6] + 256 * buf[7]; | |
341 | size = img->w * img->h; | |
342 | interl = ((buf[8] & 0x40)? 1 : 0); | |
343 | ||
344 | /* load local color map if available */ | |
345 | if ((buf[8] & 0x80) == 0x80) | |
346 | { | |
347 | ncolors = 2 << (buf[8] & 0x07); | |
53b7ce7e | 348 | f -> Read(pal, 3 * ncolors); |
b59bf2db JS |
349 | } |
350 | ||
351 | /* get initial code size from first byte in raster data */ | |
53b7ce7e | 352 | bits = mygetc(); |
b59bf2db JS |
353 | |
354 | /* allocate memory for image and palette */ | |
355 | if ((img->p = (unsigned char*) malloc(size)) == NULL) return E_MEMORIA; | |
356 | if ((img->pal = (unsigned char*) malloc(768)) == NULL) return E_MEMORIA; | |
357 | ||
358 | /* shift palette to fit VGA 6-bit format */ | |
359 | for (i = 0; i < 768; i++) | |
360 | (img->pal)[i] = (unsigned char)pal[i] /* >> 2 not needed under wxWin */; | |
361 | ||
362 | /* decode GIF */ | |
363 | dgif(img, interl, bits); | |
364 | ||
365 | /* finish successfully :-) */ | |
366 | return E_OK; | |
367 | } | |
368 | ||
369 | /* | |
370 | ||
371 | FOLLOWING CODE IS BY V.S. : | |
372 | ||
373 | */ | |
374 | ||
375 | //----------------------------------------------------------------------------- | |
376 | // wxGIFHandler | |
377 | //----------------------------------------------------------------------------- | |
378 | ||
379 | IMPLEMENT_DYNAMIC_CLASS(wxGIFHandler,wxImageHandler) | |
380 | ||
381 | bool wxGIFHandler::LoadFile( wxImage *image, wxInputStream& stream ) | |
382 | { | |
383 | unsigned char *ptr, *src, *pal; | |
b59bf2db JS |
384 | IMAGEN igif; |
385 | int i; | |
386 | gifDecoder *decod; | |
387 | ||
388 | image->Destroy(); | |
389 | ||
53b7ce7e | 390 | decod = new gifDecoder(&stream); |
b59bf2db JS |
391 | |
392 | if (decod -> readgif(&igif) != E_OK) { | |
50920146 | 393 | wxLogDebug(_T("Error reading GIF")); |
b59bf2db JS |
394 | delete decod; |
395 | return FALSE; | |
396 | } | |
b59bf2db JS |
397 | delete decod; |
398 | ||
399 | image->Create(igif.w, igif.h); | |
400 | if (!image->Ok()) { | |
401 | free(igif.pal); | |
402 | free(igif.p); | |
403 | return FALSE; | |
404 | } | |
405 | image->SetMask(FALSE); | |
406 | ||
407 | ptr = image->GetData(); | |
408 | src = igif.p; | |
409 | pal = igif.pal; | |
410 | for (i = 0; i < igif.w * igif.h; i++, src++) { | |
411 | *(ptr++) = pal[3 * (*src) + 0]; | |
412 | *(ptr++) = pal[3 * (*src) + 1]; | |
413 | *(ptr++) = pal[3 * (*src) + 2]; | |
414 | } | |
415 | ||
99cc0158 VS |
416 | if (igif.transparent != -1) { |
417 | wxLogDebug("oko"); | |
418 | image->SetMaskColour(pal[3 * (igif.transparent) + 0], pal[3 * (igif.transparent) + 0], pal[3 * (igif.transparent) + 0]); | |
419 | image->SetMask(TRUE); | |
420 | } | |
421 | ||
422 | wxLogDebug("(unsigned int)%i", (unsigned int)-1); | |
b59bf2db JS |
423 | free(igif.pal); |
424 | free(igif.p); | |
425 | return TRUE; | |
426 | } | |
427 | ||
428 | bool wxGIFHandler::SaveFile( wxImage *image, wxOutputStream& stream ) | |
429 | { | |
50920146 | 430 | wxLogDebug(_T("wxGIFHandler is read-only!!")); |
b59bf2db JS |
431 | return FALSE; |
432 | } | |
433 | ||
b59bf2db | 434 | |
99cc0158 VS |
435 | |
436 | ||
437 | ||
438 | ||
439 |