src/video/SDL_pixels.c
author Sam Lantinga <slouken@libsdl.org>
Thu, 29 May 2003 04:29:13 +0000
changeset 628 e561e8752d33
parent 297 f6ffac90895c
child 688 c0522010bb6d
permissions -rw-r--r--
*** empty log message ***
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Library General Public
     7     License as published by the Free Software Foundation; either
     8     version 2 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     Library General Public License for more details.
    14 
    15     You should have received a copy of the GNU Library General Public
    16     License along with this library; if not, write to the Free
    17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 #ifdef SAVE_RCSID
    24 static char rcsid =
    25  "@(#) $Id$";
    26 #endif
    27 
    28 /* General (mostly internal) pixel/color manipulation routines for SDL */
    29 
    30 #include <stdio.h>
    31 #include <stdlib.h>
    32 #include <string.h>
    33 
    34 #include "SDL_error.h"
    35 #include "SDL_endian.h"
    36 #include "SDL_video.h"
    37 #include "SDL_sysvideo.h"
    38 #include "SDL_blit.h"
    39 #include "SDL_pixels_c.h"
    40 #include "SDL_RLEaccel_c.h"
    41 
    42 /* Helper functions */
    43 /*
    44  * Allocate a pixel format structure and fill it according to the given info.
    45  */
    46 SDL_PixelFormat *SDL_AllocFormat(int bpp,
    47 			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
    48 {
    49 	SDL_PixelFormat *format;
    50 	Uint32 mask;
    51 
    52 	/* Allocate an empty pixel format structure */
    53 	format = malloc(sizeof(*format));
    54 	if ( format == NULL ) {
    55 		SDL_OutOfMemory();
    56 		return(NULL);
    57 	}
    58 	memset(format, 0, sizeof(*format));
    59 	format->alpha = SDL_ALPHA_OPAQUE;
    60 
    61 	/* Set up the format */
    62 	format->BitsPerPixel = bpp;
    63 	format->BytesPerPixel = (bpp+7)/8;
    64 	switch (bpp) {
    65 		case 1:
    66 			/* Create the 2 color black-white palette */
    67 			format->palette = (SDL_Palette *)malloc(
    68 							sizeof(SDL_Palette));
    69 			if ( format->palette == NULL ) {
    70 				SDL_FreeFormat(format);
    71 				SDL_OutOfMemory();
    72 				return(NULL);
    73 			}
    74 			(format->palette)->ncolors = 2;
    75 			(format->palette)->colors = (SDL_Color *)malloc(
    76 				(format->palette)->ncolors*sizeof(SDL_Color));
    77 			if ( (format->palette)->colors == NULL ) {
    78 				SDL_FreeFormat(format);
    79 				SDL_OutOfMemory();
    80 				return(NULL);
    81 			}
    82 			format->palette->colors[0].r = 0xFF;
    83 			format->palette->colors[0].g = 0xFF;
    84 			format->palette->colors[0].b = 0xFF;
    85 			format->palette->colors[1].r = 0x00;
    86 			format->palette->colors[1].g = 0x00;
    87 			format->palette->colors[1].b = 0x00;
    88 			format->Rloss = 8;
    89 			format->Gloss = 8;
    90 			format->Bloss = 8;
    91 			format->Aloss = 8;
    92 			format->Rshift = 0;
    93 			format->Gshift = 0;
    94 			format->Bshift = 0;
    95 			format->Ashift = 0;
    96 			format->Rmask = 0;
    97 			format->Gmask = 0;
    98 			format->Bmask = 0;
    99 			format->Amask = 0;
   100 			break;
   101 
   102 		case 4:
   103 			/* Create the 16 color VGA palette */
   104 			format->palette = (SDL_Palette *)malloc(
   105 							sizeof(SDL_Palette));
   106 			if ( format->palette == NULL ) {
   107 				SDL_FreeFormat(format);
   108 				SDL_OutOfMemory();
   109 				return(NULL);
   110 			}
   111 			(format->palette)->ncolors = 16;
   112 			(format->palette)->colors = (SDL_Color *)malloc(
   113 				(format->palette)->ncolors*sizeof(SDL_Color));
   114 			if ( (format->palette)->colors == NULL ) {
   115 				SDL_FreeFormat(format);
   116 				SDL_OutOfMemory();
   117 				return(NULL);
   118 			}
   119 			/* Punt for now, will this ever be used? */
   120 			memset((format->palette)->colors, 0,
   121 				(format->palette)->ncolors*sizeof(SDL_Color));
   122 
   123 			/* Palettized formats have no mask info */
   124 			format->Rloss = 8;
   125 			format->Gloss = 8;
   126 			format->Bloss = 8;
   127 			format->Aloss = 8;
   128 			format->Rshift = 0;
   129 			format->Gshift = 0;
   130 			format->Bshift = 0;
   131 			format->Ashift = 0;
   132 			format->Rmask = 0;
   133 			format->Gmask = 0;
   134 			format->Bmask = 0;
   135 			format->Amask = 0;
   136 			break;
   137 
   138 		case 8:
   139 			/* Create an empty 256 color palette */
   140 			format->palette = (SDL_Palette *)malloc(
   141 							sizeof(SDL_Palette));
   142 			if ( format->palette == NULL ) {
   143 				SDL_FreeFormat(format);
   144 				SDL_OutOfMemory();
   145 				return(NULL);
   146 			}
   147 			(format->palette)->ncolors = 256;
   148 			(format->palette)->colors = (SDL_Color *)malloc(
   149 				(format->palette)->ncolors*sizeof(SDL_Color));
   150 			if ( (format->palette)->colors == NULL ) {
   151 				SDL_FreeFormat(format);
   152 				SDL_OutOfMemory();
   153 				return(NULL);
   154 			}
   155 			memset((format->palette)->colors, 0,
   156 				(format->palette)->ncolors*sizeof(SDL_Color));
   157 
   158 			/* Palettized formats have no mask info */
   159 			format->Rloss = 8;
   160 			format->Gloss = 8;
   161 			format->Bloss = 8;
   162 			format->Aloss = 8;
   163 			format->Rshift = 0;
   164 			format->Gshift = 0;
   165 			format->Bshift = 0;
   166 			format->Ashift = 0;
   167 			format->Rmask = 0;
   168 			format->Gmask = 0;
   169 			format->Bmask = 0;
   170 			format->Amask = 0;
   171 			break;
   172 
   173 		default:
   174 			/* No palette, just packed pixel info */
   175 			format->palette = NULL;
   176 			format->Rshift = 0;
   177 			format->Rloss = 8;
   178 			if ( Rmask ) {
   179 				for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
   180 					++format->Rshift;
   181 				for ( ; (mask&0x01); mask >>= 1 )
   182 					--format->Rloss;
   183 			}
   184 			format->Gshift = 0;
   185 			format->Gloss = 8;
   186 			if ( Gmask ) {
   187 				for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
   188 					++format->Gshift;
   189 				for ( ; (mask&0x01); mask >>= 1 )
   190 					--format->Gloss;
   191 			}
   192 			format->Bshift = 0;
   193 			format->Bloss = 8;
   194 			if ( Bmask ) {
   195 				for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
   196 					++format->Bshift;
   197 				for ( ; (mask&0x01); mask >>= 1 )
   198 					--format->Bloss;
   199 			}
   200 			format->Ashift = 0;
   201 			format->Aloss = 8;
   202 			if ( Amask ) {
   203 				for ( mask = Amask; !(mask&0x01); mask >>= 1 )
   204 					++format->Ashift;
   205 				for ( ; (mask&0x01); mask >>= 1 )
   206 					--format->Aloss;
   207 			}
   208 			format->Rmask = Rmask;
   209 			format->Gmask = Gmask;
   210 			format->Bmask = Bmask;
   211 			format->Amask = Amask;
   212 			break;
   213 	}
   214 	/* Calculate some standard bitmasks, if necessary 
   215 	 * Note:  This could conflict with an alpha mask, if given.
   216 	 */
   217 	if ( (bpp > 8) && !format->Rmask && !format->Gmask && !format->Bmask ) {
   218 		/* R-G-B */
   219 		if ( bpp > 24 )
   220 			bpp = 24;
   221 		format->Rloss = 8-(bpp/3);
   222 		format->Gloss = 8-(bpp/3)-(bpp%3);
   223 		format->Bloss = 8-(bpp/3);
   224 		format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3);
   225 		format->Gshift = (bpp/3);
   226 		format->Bshift = 0;
   227 		format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
   228 		format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
   229 		format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
   230 	}
   231 	return(format);
   232 }
   233 SDL_PixelFormat *SDL_ReallocFormat(SDL_Surface *surface, int bpp,
   234 			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
   235 {
   236 	if ( surface->format ) {
   237 		SDL_FreeFormat(surface->format);
   238 		SDL_FormatChanged(surface);
   239 	}
   240 	surface->format = SDL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask);
   241 	return surface->format;
   242 }
   243 
   244 /*
   245  * Change any previous mappings from/to the new surface format
   246  */
   247 void SDL_FormatChanged(SDL_Surface *surface)
   248 {
   249 	surface->format_version++;
   250 	SDL_InvalidateMap(surface->map);
   251 }
   252 /*
   253  * Free a previously allocated format structure
   254  */
   255 void SDL_FreeFormat(SDL_PixelFormat *format)
   256 {
   257 	if ( format ) {
   258 		if ( format->palette ) {
   259 			if ( format->palette->colors ) {
   260 				free(format->palette->colors);
   261 			}
   262 			free(format->palette);
   263 		}
   264 		free(format);
   265 	}
   266 }
   267 /*
   268  * Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors
   269  */
   270 void SDL_DitherColors(SDL_Color *colors, int bpp)
   271 {
   272 	int i;
   273 	if(bpp != 8)
   274 		return;		/* only 8bpp supported right now */
   275 
   276 	for(i = 0; i < 256; i++) {
   277 		int r, g, b;
   278 		/* map each bit field to the full [0, 255] interval,
   279 		   so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */
   280 		r = i & 0xe0;
   281 		r |= r >> 3 | r >> 6;
   282 		colors[i].r = r;
   283 		g = (i << 3) & 0xe0;
   284 		g |= g >> 3 | g >> 6;
   285 		colors[i].g = g;
   286 		b = i & 0x3;
   287 		b |= b << 2;
   288 		b |= b << 4;
   289 		colors[i].b = b;
   290 	}
   291 }
   292 /* 
   293  * Calculate the pad-aligned scanline width of a surface
   294  */
   295 Uint16 SDL_CalculatePitch(SDL_Surface *surface)
   296 {
   297 	Uint16 pitch;
   298 
   299 	/* Surface should be 4-byte aligned for speed */
   300 	pitch = surface->w*surface->format->BytesPerPixel;
   301 	switch (surface->format->BitsPerPixel) {
   302 		case 1:
   303 			pitch = (pitch+7)/8;
   304 			break;
   305 		case 4:
   306 			pitch = (pitch+1)/2;
   307 			break;
   308 		default:
   309 			break;
   310 	}
   311 	pitch = (pitch + 3) & ~3;	/* 4-byte aligning */
   312 	return(pitch);
   313 }
   314 /*
   315  * Match an RGB value to a particular palette index
   316  */
   317 Uint8 SDL_FindColor(SDL_Palette *pal, Uint8 r, Uint8 g, Uint8 b)
   318 {
   319 	/* Do colorspace distance matching */
   320 	unsigned int smallest;
   321 	unsigned int distance;
   322 	int rd, gd, bd;
   323 	int i;
   324 	Uint8 pixel=0;
   325 		
   326 	smallest = ~0;
   327 	for ( i=0; i<pal->ncolors; ++i ) {
   328 		rd = pal->colors[i].r - r;
   329 		gd = pal->colors[i].g - g;
   330 		bd = pal->colors[i].b - b;
   331 		distance = (rd*rd)+(gd*gd)+(bd*bd);
   332 		if ( distance < smallest ) {
   333 			pixel = i;
   334 			if ( distance == 0 ) { /* Perfect match! */
   335 				break;
   336 			}
   337 			smallest = distance;
   338 		}
   339 	}
   340 	return(pixel);
   341 }
   342 
   343 /* Find the opaque pixel value corresponding to an RGB triple */
   344 Uint32 SDL_MapRGB(SDL_PixelFormat *format, Uint8 r, Uint8 g, Uint8 b)
   345 {
   346 	if ( format->palette == NULL ) {
   347 		return (r >> format->Rloss) << format->Rshift
   348 		       | (g >> format->Gloss) << format->Gshift
   349 		       | (b >> format->Bloss) << format->Bshift
   350 		       | format->Amask;
   351 	} else {
   352 		return SDL_FindColor(format->palette, r, g, b);
   353 	}
   354 }
   355 
   356 /* Find the pixel value corresponding to an RGBA quadruple */
   357 Uint32 SDL_MapRGBA(SDL_PixelFormat *format, Uint8 r, Uint8 g, Uint8 b, 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 
   369 void SDL_GetRGBA(Uint32 pixel, SDL_PixelFormat *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));
   385 		v = (pixel & fmt->Gmask) >> fmt->Gshift;
   386 		*g = (v << fmt->Gloss) + (v >> (8 - fmt->Gloss));
   387 		v = (pixel & fmt->Bmask) >> fmt->Bshift;
   388 		*b = (v << fmt->Bloss) + (v >> (8 - fmt->Bloss));
   389 		if(fmt->Amask) {
   390 		        v = (pixel & fmt->Amask) >> fmt->Ashift;
   391 			*a = (v << fmt->Aloss) + (v >> (8 - fmt->Aloss));
   392 		} else
   393 		        *a = SDL_ALPHA_OPAQUE;
   394 	} else {
   395 		*r = fmt->palette->colors[pixel].r;
   396 		*g = fmt->palette->colors[pixel].g;
   397 		*b = fmt->palette->colors[pixel].b;
   398 		*a = SDL_ALPHA_OPAQUE;
   399 	}
   400 }
   401 
   402 void SDL_GetRGB(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r,Uint8 *g,Uint8 *b)
   403 {
   404 	if ( fmt->palette == NULL ) {
   405 	        /* the note for SDL_GetRGBA above applies here too */
   406 	        unsigned v;
   407 		v = (pixel & fmt->Rmask) >> fmt->Rshift;
   408 		*r = (v << fmt->Rloss) + (v >> (8 - fmt->Rloss));
   409 		v = (pixel & fmt->Gmask) >> fmt->Gshift;
   410 		*g = (v << fmt->Gloss) + (v >> (8 - fmt->Gloss));
   411 		v = (pixel & fmt->Bmask) >> fmt->Bshift;
   412 		*b = (v << fmt->Bloss) + (v >> (8 - fmt->Bloss));
   413 	} else {
   414 		*r = fmt->palette->colors[pixel].r;
   415 		*g = fmt->palette->colors[pixel].g;
   416 		*b = fmt->palette->colors[pixel].b;
   417 	}
   418 }
   419 
   420 /* Apply gamma to a set of colors - this is easy. :) */
   421 void SDL_ApplyGamma(Uint16 *gamma, SDL_Color *colors, SDL_Color *output,
   422 							int ncolors)
   423 {
   424 	int i;
   425 
   426 	for ( i=0; i<ncolors; ++i ) {
   427 		output[i].r = gamma[0*256 + colors[i].r] >> 8;
   428 		output[i].g = gamma[1*256 + colors[i].g] >> 8;
   429 		output[i].b = gamma[2*256 + colors[i].b] >> 8;
   430 	}
   431 }
   432 
   433 /* Map from Palette to Palette */
   434 static Uint8 *Map1to1(SDL_Palette *src, SDL_Palette *dst, int *identical)
   435 {
   436 	Uint8 *map;
   437 	int i;
   438 
   439 	if ( identical ) {
   440 		if ( src->ncolors <= dst->ncolors ) {
   441 			/* If an identical palette, no need to map */
   442 			if ( memcmp(src->colors, dst->colors, src->ncolors*
   443 						sizeof(SDL_Color)) == 0 ) {
   444 				*identical = 1;
   445 				return(NULL);
   446 			}
   447 		}
   448 		*identical = 0;
   449 	}
   450 	map = (Uint8 *)malloc(src->ncolors);
   451 	if ( map == NULL ) {
   452 		SDL_OutOfMemory();
   453 		return(NULL);
   454 	}
   455 	for ( i=0; i<src->ncolors; ++i ) {
   456 		map[i] = SDL_FindColor(dst,
   457 			src->colors[i].r, src->colors[i].g, src->colors[i].b);
   458 	}
   459 	return(map);
   460 }
   461 /* Map from Palette to BitField */
   462 static Uint8 *Map1toN(SDL_Palette *src, SDL_PixelFormat *dst)
   463 {
   464 	Uint8 *map;
   465 	int i;
   466 	int  bpp;
   467 	unsigned alpha;
   468 
   469 	bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);
   470 	map = (Uint8 *)malloc(src->ncolors*bpp);
   471 	if ( map == NULL ) {
   472 		SDL_OutOfMemory();
   473 		return(NULL);
   474 	}
   475 
   476 	alpha = dst->Amask ? SDL_ALPHA_OPAQUE : 0;
   477 	/* We memory copy to the pixel map so the endianness is preserved */
   478 	for ( i=0; i<src->ncolors; ++i ) {
   479 		ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst,
   480 			      src->colors[i].r, src->colors[i].g,
   481 			      src->colors[i].b, alpha);
   482 	}
   483 	return(map);
   484 }
   485 /* Map from BitField to Dithered-Palette to Palette */
   486 static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_Palette *dst, int *identical)
   487 {
   488 	/* Generate a 256 color dither palette */
   489 	SDL_Palette dithered;
   490 	SDL_Color colors[256];
   491 
   492 	dithered.ncolors = 256;
   493 	SDL_DitherColors(colors, 8);
   494 	dithered.colors = colors;
   495 	return(Map1to1(&dithered, dst, identical));
   496 }
   497 
   498 SDL_BlitMap *SDL_AllocBlitMap(void)
   499 {
   500 	SDL_BlitMap *map;
   501 
   502 	/* Allocate the empty map */
   503 	map = (SDL_BlitMap *)malloc(sizeof(*map));
   504 	if ( map == NULL ) {
   505 		SDL_OutOfMemory();
   506 		return(NULL);
   507 	}
   508 	memset(map, 0, sizeof(*map));
   509 
   510 	/* Allocate the software blit data */
   511 	map->sw_data = (struct private_swaccel *)malloc(sizeof(*map->sw_data));
   512 	if ( map->sw_data == NULL ) {
   513 		SDL_FreeBlitMap(map);
   514 		SDL_OutOfMemory();
   515 		return(NULL);
   516 	}
   517 	memset(map->sw_data, 0, sizeof(*map->sw_data));
   518 
   519 	/* It's ready to go */
   520 	return(map);
   521 }
   522 void SDL_InvalidateMap(SDL_BlitMap *map)
   523 {
   524 	if ( ! map ) {
   525 		return;
   526 	}
   527 	map->dst = NULL;
   528 	map->format_version = (unsigned int)-1;
   529 	if ( map->table ) {
   530 		free(map->table);
   531 		map->table = NULL;
   532 	}
   533 }
   534 int SDL_MapSurface (SDL_Surface *src, SDL_Surface *dst)
   535 {
   536 	SDL_PixelFormat *srcfmt;
   537 	SDL_PixelFormat *dstfmt;
   538 	SDL_BlitMap *map;
   539 
   540 	/* Clear out any previous mapping */
   541 	map = src->map;
   542 	if ( (src->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
   543 		SDL_UnRLESurface(src, 1);
   544 	}
   545 	SDL_InvalidateMap(map);
   546 
   547 	/* Figure out what kind of mapping we're doing */
   548 	map->identity = 0;
   549 	srcfmt = src->format;
   550 	dstfmt = dst->format;
   551 	switch (srcfmt->BytesPerPixel) {
   552 	    case 1:
   553 		switch (dstfmt->BytesPerPixel) {
   554 		    case 1:
   555 			/* Palette --> Palette */
   556 			/* If both SDL_HWSURFACE, assume have same palette */
   557 			if ( ((src->flags & SDL_HWSURFACE) == SDL_HWSURFACE) &&
   558 			     ((dst->flags & SDL_HWSURFACE) == SDL_HWSURFACE) ) {
   559 				map->identity = 1;
   560 			} else {
   561 				map->table = Map1to1(srcfmt->palette,
   562 					dstfmt->palette, &map->identity);
   563 			}
   564 			if ( ! map->identity ) {
   565 				if ( map->table == NULL ) {
   566 					return(-1);
   567 				}
   568 			}
   569 			if (srcfmt->BitsPerPixel!=dstfmt->BitsPerPixel)
   570 				map->identity = 0;
   571 			break;
   572 
   573 		    default:
   574 			/* Palette --> BitField */
   575 			map->table = Map1toN(srcfmt->palette, dstfmt);
   576 			if ( map->table == NULL ) {
   577 				return(-1);
   578 			}
   579 			break;
   580 		}
   581 		break;
   582 	default:
   583 		switch (dstfmt->BytesPerPixel) {
   584 		    case 1:
   585 			/* BitField --> Palette */
   586 			map->table = MapNto1(srcfmt,
   587 					dstfmt->palette, &map->identity);
   588 			if ( ! map->identity ) {
   589 				if ( map->table == NULL ) {
   590 					return(-1);
   591 				}
   592 			}
   593 			map->identity = 0;	/* Don't optimize to copy */
   594 			break;
   595 		    default:
   596 			/* BitField --> BitField */
   597 			if ( FORMAT_EQUAL(srcfmt, dstfmt) )
   598 				map->identity = 1;
   599 			break;
   600 		}
   601 		break;
   602 	}
   603 
   604 	map->dst = dst;
   605 	map->format_version = dst->format_version;
   606 
   607 	/* Choose your blitters wisely */
   608 	return(SDL_CalculateBlit(src));
   609 }
   610 void SDL_FreeBlitMap(SDL_BlitMap *map)
   611 {
   612 	if ( map ) {
   613 		SDL_InvalidateMap(map);
   614 		if ( map->sw_data != NULL ) {
   615 			free(map->sw_data);
   616 		}
   617 		free(map);
   618 	}
   619 }