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1 /*
2     SDL - Simple DirectMedia Layer
3     Copyright (C) 1997-2012 Sam Lantinga
4 
5     This library is free software; you can redistribute it and/or
6     modify it under the terms of the GNU Lesser General Public
7     License as published by the Free Software Foundation; either
8     version 2.1 of the License, or (at your option) any later version.
9 
10     This library is distributed in the hope that it will be useful,
11     but WITHOUT ANY WARRANTY; without even the implied warranty of
12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13     Lesser General Public License for more details.
14 
15     You should have received a copy of the GNU Lesser General Public
16     License along with this library; if not, write to the Free Software
17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18 
19     Sam Lantinga
20     slouken@libsdl.org
21 */
22 #include "SDL_config.h"
23 
24 /* General (mostly internal) pixel/color manipulation routines for SDL */
25 
26 #include "SDL_endian.h"
27 #include "SDL_video.h"
28 #include "SDL_sysvideo.h"
29 #include "SDL_blit.h"
30 #include "SDL_pixels_c.h"
31 #include "SDL_RLEaccel_c.h"
32 
33 /* Helper functions */
34 /*
35  * Allocate a pixel format structure and fill it according to the given info.
36  */
SDL_AllocFormat(int bpp,Uint32 Rmask,Uint32 Gmask,Uint32 Bmask,Uint32 Amask)37 SDL_PixelFormat *SDL_AllocFormat(int bpp,
38 			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
39 {
40 	SDL_PixelFormat *format;
41 	Uint32 mask;
42 
43 	/* Allocate an empty pixel format structure */
44 	format = SDL_malloc(sizeof(*format));
45 	if ( format == NULL ) {
46 		SDL_OutOfMemory();
47 		return(NULL);
48 	}
49 	SDL_memset(format, 0, sizeof(*format));
50 	format->alpha = SDL_ALPHA_OPAQUE;
51 
52 	/* Set up the format */
53 	format->BitsPerPixel = bpp;
54 	format->BytesPerPixel = (bpp+7)/8;
55 	if ( Rmask || Bmask || Gmask ) { /* Packed pixels with custom mask */
56 		format->palette = NULL;
57 		format->Rshift = 0;
58 		format->Rloss = 8;
59 		if ( Rmask ) {
60 			for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
61 				++format->Rshift;
62 			for ( ; (mask&0x01); mask >>= 1 )
63 				--format->Rloss;
64 		}
65 		format->Gshift = 0;
66 		format->Gloss = 8;
67 		if ( Gmask ) {
68 			for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
69 				++format->Gshift;
70 			for ( ; (mask&0x01); mask >>= 1 )
71 				--format->Gloss;
72 		}
73 		format->Bshift = 0;
74 		format->Bloss = 8;
75 		if ( Bmask ) {
76 			for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
77 				++format->Bshift;
78 			for ( ; (mask&0x01); mask >>= 1 )
79 				--format->Bloss;
80 		}
81 		format->Ashift = 0;
82 		format->Aloss = 8;
83 		if ( Amask ) {
84 			for ( mask = Amask; !(mask&0x01); mask >>= 1 )
85 				++format->Ashift;
86 			for ( ; (mask&0x01); mask >>= 1 )
87 				--format->Aloss;
88 		}
89 		format->Rmask = Rmask;
90 		format->Gmask = Gmask;
91 		format->Bmask = Bmask;
92 		format->Amask = Amask;
93 	} else if ( bpp > 8 ) {		/* Packed pixels with standard mask */
94 		/* R-G-B */
95 		if ( bpp > 24 )
96 			bpp = 24;
97 		format->Rloss = 8-(bpp/3);
98 		format->Gloss = 8-(bpp/3)-(bpp%3);
99 		format->Bloss = 8-(bpp/3);
100 		format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3);
101 		format->Gshift = (bpp/3);
102 		format->Bshift = 0;
103 		format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
104 		format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
105 		format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
106 	} else {
107 		/* Palettized formats have no mask info */
108 		format->Rloss = 8;
109 		format->Gloss = 8;
110 		format->Bloss = 8;
111 		format->Aloss = 8;
112 		format->Rshift = 0;
113 		format->Gshift = 0;
114 		format->Bshift = 0;
115 		format->Ashift = 0;
116 		format->Rmask = 0;
117 		format->Gmask = 0;
118 		format->Bmask = 0;
119 		format->Amask = 0;
120 	}
121 	if ( bpp <= 8 ) {			/* Palettized mode */
122 		int ncolors = 1<<bpp;
123 #ifdef DEBUG_PALETTE
124 		fprintf(stderr,"bpp=%d ncolors=%d\n",bpp,ncolors);
125 #endif
126 		format->palette = (SDL_Palette *)SDL_malloc(sizeof(SDL_Palette));
127 		if ( format->palette == NULL ) {
128 			SDL_FreeFormat(format);
129 			SDL_OutOfMemory();
130 			return(NULL);
131 		}
132 		(format->palette)->ncolors = ncolors;
133 		(format->palette)->colors = (SDL_Color *)SDL_malloc(
134 				(format->palette)->ncolors*sizeof(SDL_Color));
135 		if ( (format->palette)->colors == NULL ) {
136 			SDL_FreeFormat(format);
137 			SDL_OutOfMemory();
138 			return(NULL);
139 		}
140 		if ( Rmask || Bmask || Gmask ) {
141 			/* create palette according to masks */
142 			int i;
143 			int Rm=0,Gm=0,Bm=0;
144 			int Rw=0,Gw=0,Bw=0;
145 #ifdef ENABLE_PALETTE_ALPHA
146 			int Am=0,Aw=0;
147 #endif
148 			if(Rmask)
149 			{
150 				Rw=8-format->Rloss;
151 				for(i=format->Rloss;i>0;i-=Rw)
152 					Rm|=1<<i;
153 			}
154 #ifdef DEBUG_PALETTE
155 			fprintf(stderr,"Rw=%d Rm=0x%02X\n",Rw,Rm);
156 #endif
157 			if(Gmask)
158 			{
159 				Gw=8-format->Gloss;
160 				for(i=format->Gloss;i>0;i-=Gw)
161 					Gm|=1<<i;
162 			}
163 #ifdef DEBUG_PALETTE
164 			fprintf(stderr,"Gw=%d Gm=0x%02X\n",Gw,Gm);
165 #endif
166 			if(Bmask)
167 			{
168 				Bw=8-format->Bloss;
169 				for(i=format->Bloss;i>0;i-=Bw)
170 					Bm|=1<<i;
171 			}
172 #ifdef DEBUG_PALETTE
173 			fprintf(stderr,"Bw=%d Bm=0x%02X\n",Bw,Bm);
174 #endif
175 #ifdef ENABLE_PALETTE_ALPHA
176 			if(Amask)
177 			{
178 				Aw=8-format->Aloss;
179 				for(i=format->Aloss;i>0;i-=Aw)
180 					Am|=1<<i;
181 			}
182 # ifdef DEBUG_PALETTE
183 			fprintf(stderr,"Aw=%d Am=0x%02X\n",Aw,Am);
184 # endif
185 #endif
186 			for(i=0; i < ncolors; ++i) {
187 				int r,g,b;
188 				r=(i&Rmask)>>format->Rshift;
189 				r=(r<<format->Rloss)|((r*Rm)>>Rw);
190 				format->palette->colors[i].r=r;
191 
192 				g=(i&Gmask)>>format->Gshift;
193 				g=(g<<format->Gloss)|((g*Gm)>>Gw);
194 				format->palette->colors[i].g=g;
195 
196 				b=(i&Bmask)>>format->Bshift;
197 				b=(b<<format->Bloss)|((b*Bm)>>Bw);
198 				format->palette->colors[i].b=b;
199 
200 #ifdef ENABLE_PALETTE_ALPHA
201 				a=(i&Amask)>>format->Ashift;
202 				a=(a<<format->Aloss)|((a*Am)>>Aw);
203 				format->palette->colors[i].unused=a;
204 #else
205 				format->palette->colors[i].unused=0;
206 #endif
207 			}
208 		} else if ( ncolors == 2 ) {
209 			/* Create a black and white bitmap palette */
210 			format->palette->colors[0].r = 0xFF;
211 			format->palette->colors[0].g = 0xFF;
212 			format->palette->colors[0].b = 0xFF;
213 			format->palette->colors[1].r = 0x00;
214 			format->palette->colors[1].g = 0x00;
215 			format->palette->colors[1].b = 0x00;
216 		} else {
217 			/* Create an empty palette */
218 			SDL_memset((format->palette)->colors, 0,
219 				(format->palette)->ncolors*sizeof(SDL_Color));
220 		}
221 	}
222 	return(format);
223 }
SDL_ReallocFormat(SDL_Surface * surface,int bpp,Uint32 Rmask,Uint32 Gmask,Uint32 Bmask,Uint32 Amask)224 SDL_PixelFormat *SDL_ReallocFormat(SDL_Surface *surface, int bpp,
225 			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
226 {
227 	if ( surface->format ) {
228 		SDL_FreeFormat(surface->format);
229 		SDL_FormatChanged(surface);
230 	}
231 	surface->format = SDL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask);
232 	return surface->format;
233 }
234 
235 /*
236  * Change any previous mappings from/to the new surface format
237  */
SDL_FormatChanged(SDL_Surface * surface)238 void SDL_FormatChanged(SDL_Surface *surface)
239 {
240 	static int format_version = 0;
241 	++format_version;
242 	if ( format_version < 0 ) { /* It wrapped... */
243 		format_version = 1;
244 	}
245 	surface->format_version = format_version;
246 	SDL_InvalidateMap(surface->map);
247 }
248 /*
249  * Free a previously allocated format structure
250  */
SDL_FreeFormat(SDL_PixelFormat * format)251 void SDL_FreeFormat(SDL_PixelFormat *format)
252 {
253 	if ( format ) {
254 		if ( format->palette ) {
255 			if ( format->palette->colors ) {
256 				SDL_free(format->palette->colors);
257 			}
258 			SDL_free(format->palette);
259 		}
260 		SDL_free(format);
261 	}
262 }
263 /*
264  * Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors
265  */
SDL_DitherColors(SDL_Color * colors,int bpp)266 void SDL_DitherColors(SDL_Color *colors, int bpp)
267 {
268 	int i;
269 	if(bpp != 8)
270 		return;		/* only 8bpp supported right now */
271 
272 	for(i = 0; i < 256; i++) {
273 		int r, g, b;
274 		/* map each bit field to the full [0, 255] interval,
275 		   so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */
276 		r = i & 0xe0;
277 		r |= r >> 3 | r >> 6;
278 		colors[i].r = r;
279 		g = (i << 3) & 0xe0;
280 		g |= g >> 3 | g >> 6;
281 		colors[i].g = g;
282 		b = i & 0x3;
283 		b |= b << 2;
284 		b |= b << 4;
285 		colors[i].b = b;
286 	}
287 }
288 /*
289  * Calculate the pad-aligned scanline width of a surface
290  */
SDL_CalculatePitch(SDL_Surface * surface)291 Uint16 SDL_CalculatePitch(SDL_Surface *surface)
292 {
293 	Uint16 pitch;
294 
295 	/* Surface should be 4-byte aligned for speed */
296 	pitch = surface->w*surface->format->BytesPerPixel;
297 	switch (surface->format->BitsPerPixel) {
298 		case 1:
299 			pitch = (pitch+7)/8;
300 			break;
301 		case 4:
302 			pitch = (pitch+1)/2;
303 			break;
304 		default:
305 			break;
306 	}
307 	pitch = (pitch + 3) & ~3;	/* 4-byte aligning */
308 	return(pitch);
309 }
310 /*
311  * Match an RGB value to a particular palette index
312  */
SDL_FindColor(SDL_Palette * pal,Uint8 r,Uint8 g,Uint8 b)313 Uint8 SDL_FindColor(SDL_Palette *pal, Uint8 r, Uint8 g, Uint8 b)
314 {
315 	/* Do colorspace distance matching */
316 	unsigned int smallest;
317 	unsigned int distance;
318 	int rd, gd, bd;
319 	int i;
320 	Uint8 pixel=0;
321 
322 	smallest = ~0;
323 	for ( i=0; i<pal->ncolors; ++i ) {
324 		rd = pal->colors[i].r - r;
325 		gd = pal->colors[i].g - g;
326 		bd = pal->colors[i].b - b;
327 		distance = (rd*rd)+(gd*gd)+(bd*bd);
328 		if ( distance < smallest ) {
329 			pixel = i;
330 			if ( distance == 0 ) { /* Perfect match! */
331 				break;
332 			}
333 			smallest = distance;
334 		}
335 	}
336 	return(pixel);
337 }
338 
339 /* Find the opaque pixel value corresponding to an RGB triple */
SDL_MapRGB(const SDL_PixelFormat * const format,const Uint8 r,const Uint8 g,const Uint8 b)340 Uint32 SDL_MapRGB
341 (const SDL_PixelFormat * const format,
342  const Uint8 r, const Uint8 g, const Uint8 b)
343 {
344 	if ( format->palette == NULL ) {
345 		return (r >> format->Rloss) << format->Rshift
346 		       | (g >> format->Gloss) << format->Gshift
347 		       | (b >> format->Bloss) << format->Bshift
348 		       | format->Amask;
349 	} else {
350 		return SDL_FindColor(format->palette, r, g, b);
351 	}
352 }
353 
354 /* Find the pixel value corresponding to an RGBA quadruple */
SDL_MapRGBA(const SDL_PixelFormat * const format,const Uint8 r,const Uint8 g,const Uint8 b,const Uint8 a)355 Uint32 SDL_MapRGBA
356 (const SDL_PixelFormat * const format,
357  const Uint8 r, const Uint8 g, const Uint8 b, const Uint8 a)
358 {
359 	if ( format->palette == NULL ) {
360 	        return (r >> format->Rloss) << format->Rshift
361 		    | (g >> format->Gloss) << format->Gshift
362 		    | (b >> format->Bloss) << format->Bshift
363 		    | ((a >> format->Aloss) << format->Ashift & format->Amask);
364 	} else {
365 		return SDL_FindColor(format->palette, r, g, b);
366 	}
367 }
368 
SDL_GetRGBA(Uint32 pixel,const SDL_PixelFormat * const fmt,Uint8 * r,Uint8 * g,Uint8 * b,Uint8 * a)369 void SDL_GetRGBA(Uint32 pixel, const SDL_PixelFormat * const fmt,
370 		 Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a)
371 {
372 	if ( fmt->palette == NULL ) {
373 	        /*
374 		 * This makes sure that the result is mapped to the
375 		 * interval [0..255], and the maximum value for each
376 		 * component is 255. This is important to make sure
377 		 * that white is indeed reported as (255, 255, 255),
378 		 * and that opaque alpha is 255.
379 		 * This only works for RGB bit fields at least 4 bit
380 		 * wide, which is almost always the case.
381 		 */
382 	        unsigned v;
383 		v = (pixel & fmt->Rmask) >> fmt->Rshift;
384 		*r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1)));
385 		v = (pixel & fmt->Gmask) >> fmt->Gshift;
386 		*g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1)));
387 		v = (pixel & fmt->Bmask) >> fmt->Bshift;
388 		*b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1)));
389 		if(fmt->Amask) {
390 		        v = (pixel & fmt->Amask) >> fmt->Ashift;
391 			*a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1)));
392 		} else {
393 		        *a = SDL_ALPHA_OPAQUE;
394                 }
395 	} else {
396 		*r = fmt->palette->colors[pixel].r;
397 		*g = fmt->palette->colors[pixel].g;
398 		*b = fmt->palette->colors[pixel].b;
399 		*a = SDL_ALPHA_OPAQUE;
400 	}
401 }
402 
SDL_GetRGB(Uint32 pixel,const SDL_PixelFormat * const fmt,Uint8 * r,Uint8 * g,Uint8 * b)403 void SDL_GetRGB(Uint32 pixel, const SDL_PixelFormat * const fmt,
404                 Uint8 *r,Uint8 *g,Uint8 *b)
405 {
406 	if ( fmt->palette == NULL ) {
407 	        /* the note for SDL_GetRGBA above applies here too */
408 	        unsigned v;
409 		v = (pixel & fmt->Rmask) >> fmt->Rshift;
410 		*r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1)));
411 		v = (pixel & fmt->Gmask) >> fmt->Gshift;
412 		*g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1)));
413 		v = (pixel & fmt->Bmask) >> fmt->Bshift;
414 		*b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1)));
415 	} else {
416 		*r = fmt->palette->colors[pixel].r;
417 		*g = fmt->palette->colors[pixel].g;
418 		*b = fmt->palette->colors[pixel].b;
419 	}
420 }
421 
422 /* Apply gamma to a set of colors - this is easy. :) */
SDL_ApplyGamma(Uint16 * gamma,SDL_Color * colors,SDL_Color * output,int ncolors)423 void SDL_ApplyGamma(Uint16 *gamma, SDL_Color *colors, SDL_Color *output,
424 							int ncolors)
425 {
426 	int i;
427 
428 	for ( i=0; i<ncolors; ++i ) {
429 		output[i].r = gamma[0*256 + colors[i].r] >> 8;
430 		output[i].g = gamma[1*256 + colors[i].g] >> 8;
431 		output[i].b = gamma[2*256 + colors[i].b] >> 8;
432 	}
433 }
434 
435 /* Map from Palette to Palette */
Map1to1(SDL_Palette * src,SDL_Palette * dst,int * identical)436 static Uint8 *Map1to1(SDL_Palette *src, SDL_Palette *dst, int *identical)
437 {
438 	Uint8 *map;
439 	int i;
440 
441 	if ( identical ) {
442 		if ( src->ncolors <= dst->ncolors ) {
443 			/* If an identical palette, no need to map */
444 			if ( SDL_memcmp(src->colors, dst->colors, src->ncolors*
445 						sizeof(SDL_Color)) == 0 ) {
446 				*identical = 1;
447 				return(NULL);
448 			}
449 		}
450 		*identical = 0;
451 	}
452 	map = (Uint8 *)SDL_malloc(src->ncolors);
453 	if ( map == NULL ) {
454 		SDL_OutOfMemory();
455 		return(NULL);
456 	}
457 	for ( i=0; i<src->ncolors; ++i ) {
458 		map[i] = SDL_FindColor(dst,
459 			src->colors[i].r, src->colors[i].g, src->colors[i].b);
460 	}
461 	return(map);
462 }
463 /* Map from Palette to BitField */
Map1toN(SDL_PixelFormat * src,SDL_PixelFormat * dst)464 static Uint8 *Map1toN(SDL_PixelFormat *src, SDL_PixelFormat *dst)
465 {
466 	Uint8 *map;
467 	int i;
468 	int  bpp;
469 	unsigned alpha;
470 	SDL_Palette *pal = src->palette;
471 
472 	bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);
473 	map = (Uint8 *)SDL_malloc(pal->ncolors*bpp);
474 	if ( map == NULL ) {
475 		SDL_OutOfMemory();
476 		return(NULL);
477 	}
478 
479 	alpha = dst->Amask ? src->alpha : 0;
480 	/* We memory copy to the pixel map so the endianness is preserved */
481 	for ( i=0; i<pal->ncolors; ++i ) {
482 		ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst,
483 			      pal->colors[i].r, pal->colors[i].g,
484 			      pal->colors[i].b, alpha);
485 	}
486 	return(map);
487 }
488 /* Map from BitField to Dithered-Palette to Palette */
MapNto1(SDL_PixelFormat * src,SDL_PixelFormat * dst,int * identical)489 static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_PixelFormat *dst, int *identical)
490 {
491 	/* Generate a 256 color dither palette */
492 	SDL_Palette dithered;
493 	SDL_Color colors[256];
494 	SDL_Palette *pal = dst->palette;
495 
496 	/* SDL_DitherColors does not initialize the 'unused' component of colors,
497 	   but Map1to1 compares it against pal, so we should initialize it. */
498 	SDL_memset(colors, 0, sizeof(colors));
499 
500 	dithered.ncolors = 256;
501 	SDL_DitherColors(colors, 8);
502 	dithered.colors = colors;
503 	return(Map1to1(&dithered, pal, identical));
504 }
505 
SDL_AllocBlitMap(void)506 SDL_BlitMap *SDL_AllocBlitMap(void)
507 {
508 	SDL_BlitMap *map;
509 
510 	/* Allocate the empty map */
511 	map = (SDL_BlitMap *)SDL_malloc(sizeof(*map));
512 	if ( map == NULL ) {
513 		SDL_OutOfMemory();
514 		return(NULL);
515 	}
516 	SDL_memset(map, 0, sizeof(*map));
517 
518 	/* Allocate the software blit data */
519 	map->sw_data = (struct private_swaccel *)SDL_malloc(sizeof(*map->sw_data));
520 	if ( map->sw_data == NULL ) {
521 		SDL_FreeBlitMap(map);
522 		SDL_OutOfMemory();
523 		return(NULL);
524 	}
525 	SDL_memset(map->sw_data, 0, sizeof(*map->sw_data));
526 
527 	/* It's ready to go */
528 	return(map);
529 }
SDL_InvalidateMap(SDL_BlitMap * map)530 void SDL_InvalidateMap(SDL_BlitMap *map)
531 {
532 	if ( ! map ) {
533 		return;
534 	}
535 	map->dst = NULL;
536 	map->format_version = (unsigned int)-1;
537 	if ( map->table ) {
538 		SDL_free(map->table);
539 		map->table = NULL;
540 	}
541 }
SDL_MapSurface(SDL_Surface * src,SDL_Surface * dst)542 int SDL_MapSurface (SDL_Surface *src, SDL_Surface *dst)
543 {
544 	SDL_PixelFormat *srcfmt;
545 	SDL_PixelFormat *dstfmt;
546 	SDL_BlitMap *map;
547 
548 	/* Clear out any previous mapping */
549 	map = src->map;
550 	if ( (src->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
551 		SDL_UnRLESurface(src, 1);
552 	}
553 	SDL_InvalidateMap(map);
554 
555 	/* Figure out what kind of mapping we're doing */
556 	map->identity = 0;
557 	srcfmt = src->format;
558 	dstfmt = dst->format;
559 	switch (srcfmt->BytesPerPixel) {
560 	    case 1:
561 		switch (dstfmt->BytesPerPixel) {
562 		    case 1:
563 			/* Palette --> Palette */
564 			/* If both SDL_HWSURFACE, assume have same palette */
565 			if ( ((src->flags & SDL_HWSURFACE) == SDL_HWSURFACE) &&
566 			     ((dst->flags & SDL_HWSURFACE) == SDL_HWSURFACE) ) {
567 				map->identity = 1;
568 			} else {
569 				map->table = Map1to1(srcfmt->palette,
570 					dstfmt->palette, &map->identity);
571 			}
572 			if ( ! map->identity ) {
573 				if ( map->table == NULL ) {
574 					return(-1);
575 				}
576 			}
577 			if (srcfmt->BitsPerPixel!=dstfmt->BitsPerPixel)
578 				map->identity = 0;
579 			break;
580 
581 		    default:
582 			/* Palette --> BitField */
583 			map->table = Map1toN(srcfmt, dstfmt);
584 			if ( map->table == NULL ) {
585 				return(-1);
586 			}
587 			break;
588 		}
589 		break;
590 	default:
591 		switch (dstfmt->BytesPerPixel) {
592 		    case 1:
593 			/* BitField --> Palette */
594 			map->table = MapNto1(srcfmt, dstfmt, &map->identity);
595 			if ( ! map->identity ) {
596 				if ( map->table == NULL ) {
597 					return(-1);
598 				}
599 			}
600 			map->identity = 0;	/* Don't optimize to copy */
601 			break;
602 		    default:
603 			/* BitField --> BitField */
604 			if ( FORMAT_EQUAL(srcfmt, dstfmt) )
605 				map->identity = 1;
606 			break;
607 		}
608 		break;
609 	}
610 
611 	map->dst = dst;
612 	map->format_version = dst->format_version;
613 
614 	/* Choose your blitters wisely */
615 	return(SDL_CalculateBlit(src));
616 }
SDL_FreeBlitMap(SDL_BlitMap * map)617 void SDL_FreeBlitMap(SDL_BlitMap *map)
618 {
619 	if ( map ) {
620 		SDL_InvalidateMap(map);
621 		if ( map->sw_data != NULL ) {
622 			SDL_free(map->sw_data);
623 		}
624 		SDL_free(map);
625 	}
626 }
627