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 (at) libsdl.org 21 */ 22 #include "SDL_config.h" 23 24 /* 25 Code to load and save surfaces in Windows BMP format. 26 27 Why support BMP format? Well, it's a native format for Windows, and 28 most image processing programs can read and write it. It would be nice 29 to be able to have at least one image format that we can natively load 30 and save, and since PNG is so complex that it would bloat the library, 31 BMP is a good alternative. 32 33 This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp. 34 */ 35 36 #include "SDL_video.h" 37 #include "SDL_endian.h" 38 39 /* Compression encodings for BMP files */ 40 #ifndef BI_RGB 41 #define BI_RGB 0 42 #define BI_RLE8 1 43 #define BI_RLE4 2 44 #define BI_BITFIELDS 3 45 #endif 46 47 48 SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc) 49 { 50 SDL_bool was_error; 51 long fp_offset = 0; 52 int bmpPitch; 53 int i, pad; 54 SDL_Surface *surface; 55 Uint32 Rmask; 56 Uint32 Gmask; 57 Uint32 Bmask; 58 SDL_Palette *palette; 59 Uint8 *bits; 60 Uint8 *top, *end; 61 SDL_bool topDown; 62 int ExpandBMP; 63 64 /* The Win32 BMP file header (14 bytes) */ 65 char magic[2]; 66 Uint32 bfSize; 67 Uint16 bfReserved1; 68 Uint16 bfReserved2; 69 Uint32 bfOffBits; 70 71 /* The Win32 BITMAPINFOHEADER struct (40 bytes) */ 72 Uint32 biSize; 73 Sint32 biWidth; 74 Sint32 biHeight; 75 Uint16 biPlanes; 76 Uint16 biBitCount; 77 Uint32 biCompression; 78 Uint32 biSizeImage; 79 Sint32 biXPelsPerMeter; 80 Sint32 biYPelsPerMeter; 81 Uint32 biClrUsed; 82 Uint32 biClrImportant; 83 84 /* Make sure we are passed a valid data source */ 85 surface = NULL; 86 was_error = SDL_FALSE; 87 if ( src == NULL ) { 88 was_error = SDL_TRUE; 89 goto done; 90 } 91 92 /* Read in the BMP file header */ 93 fp_offset = SDL_RWtell(src); 94 SDL_ClearError(); 95 if ( SDL_RWread(src, magic, 1, 2) != 2 ) { 96 SDL_Error(SDL_EFREAD); 97 was_error = SDL_TRUE; 98 goto done; 99 } 100 if ( SDL_strncmp(magic, "BM", 2) != 0 ) { 101 SDL_SetError("File is not a Windows BMP file"); 102 was_error = SDL_TRUE; 103 goto done; 104 } 105 bfSize = SDL_ReadLE32(src); 106 bfReserved1 = SDL_ReadLE16(src); 107 bfReserved2 = SDL_ReadLE16(src); 108 bfOffBits = SDL_ReadLE32(src); 109 110 /* Read the Win32 BITMAPINFOHEADER */ 111 biSize = SDL_ReadLE32(src); 112 if ( biSize == 12 ) { 113 biWidth = (Uint32)SDL_ReadLE16(src); 114 biHeight = (Uint32)SDL_ReadLE16(src); 115 biPlanes = SDL_ReadLE16(src); 116 biBitCount = SDL_ReadLE16(src); 117 biCompression = BI_RGB; 118 biSizeImage = 0; 119 biXPelsPerMeter = 0; 120 biYPelsPerMeter = 0; 121 biClrUsed = 0; 122 biClrImportant = 0; 123 } else { 124 biWidth = SDL_ReadLE32(src); 125 biHeight = SDL_ReadLE32(src); 126 biPlanes = SDL_ReadLE16(src); 127 biBitCount = SDL_ReadLE16(src); 128 biCompression = SDL_ReadLE32(src); 129 biSizeImage = SDL_ReadLE32(src); 130 biXPelsPerMeter = SDL_ReadLE32(src); 131 biYPelsPerMeter = SDL_ReadLE32(src); 132 biClrUsed = SDL_ReadLE32(src); 133 biClrImportant = SDL_ReadLE32(src); 134 } 135 136 /* stop some compiler warnings. */ 137 (void) bfSize; 138 (void) bfReserved1; 139 (void) bfReserved2; 140 (void) biPlanes; 141 (void) biSizeImage; 142 (void) biXPelsPerMeter; 143 (void) biYPelsPerMeter; 144 (void) biClrImportant; 145 146 if (biHeight < 0) { 147 topDown = SDL_TRUE; 148 biHeight = -biHeight; 149 } else { 150 topDown = SDL_FALSE; 151 } 152 153 /* Check for read error */ 154 if ( SDL_strcmp(SDL_GetError(), "") != 0 ) { 155 was_error = SDL_TRUE; 156 goto done; 157 } 158 159 /* Expand 1 and 4 bit bitmaps to 8 bits per pixel */ 160 switch (biBitCount) { 161 case 1: 162 case 4: 163 ExpandBMP = biBitCount; 164 biBitCount = 8; 165 break; 166 default: 167 ExpandBMP = 0; 168 break; 169 } 170 171 /* We don't support any BMP compression right now */ 172 Rmask = Gmask = Bmask = 0; 173 switch (biCompression) { 174 case BI_RGB: 175 /* If there are no masks, use the defaults */ 176 if ( bfOffBits == (14+biSize) ) { 177 /* Default values for the BMP format */ 178 switch (biBitCount) { 179 case 15: 180 case 16: 181 Rmask = 0x7C00; 182 Gmask = 0x03E0; 183 Bmask = 0x001F; 184 break; 185 case 24: 186 #if SDL_BYTEORDER == SDL_BIG_ENDIAN 187 Rmask = 0x000000FF; 188 Gmask = 0x0000FF00; 189 Bmask = 0x00FF0000; 190 break; 191 #endif 192 case 32: 193 Rmask = 0x00FF0000; 194 Gmask = 0x0000FF00; 195 Bmask = 0x000000FF; 196 break; 197 default: 198 break; 199 } 200 break; 201 } 202 /* Fall through -- read the RGB masks */ 203 204 case BI_BITFIELDS: 205 switch (biBitCount) { 206 case 15: 207 case 16: 208 case 32: 209 Rmask = SDL_ReadLE32(src); 210 Gmask = SDL_ReadLE32(src); 211 Bmask = SDL_ReadLE32(src); 212 break; 213 default: 214 break; 215 } 216 break; 217 default: 218 SDL_SetError("Compressed BMP files not supported"); 219 was_error = SDL_TRUE; 220 goto done; 221 } 222 223 /* Create a compatible surface, note that the colors are RGB ordered */ 224 surface = SDL_CreateRGBSurface(SDL_SWSURFACE, 225 biWidth, biHeight, biBitCount, Rmask, Gmask, Bmask, 0); 226 if ( surface == NULL ) { 227 was_error = SDL_TRUE; 228 goto done; 229 } 230 231 /* Load the palette, if any */ 232 palette = (surface->format)->palette; 233 if ( palette ) { 234 if ( biClrUsed == 0 ) { 235 biClrUsed = 1 << biBitCount; 236 } 237 if ( biSize == 12 ) { 238 for ( i = 0; i < (int)biClrUsed; ++i ) { 239 SDL_RWread(src, &palette->colors[i].b, 1, 1); 240 SDL_RWread(src, &palette->colors[i].g, 1, 1); 241 SDL_RWread(src, &palette->colors[i].r, 1, 1); 242 palette->colors[i].unused = 0; 243 } 244 } else { 245 for ( i = 0; i < (int)biClrUsed; ++i ) { 246 SDL_RWread(src, &palette->colors[i].b, 1, 1); 247 SDL_RWread(src, &palette->colors[i].g, 1, 1); 248 SDL_RWread(src, &palette->colors[i].r, 1, 1); 249 SDL_RWread(src, &palette->colors[i].unused, 1, 1); 250 } 251 } 252 palette->ncolors = biClrUsed; 253 } 254 255 /* Read the surface pixels. Note that the bmp image is upside down */ 256 if ( SDL_RWseek(src, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) { 257 SDL_Error(SDL_EFSEEK); 258 was_error = SDL_TRUE; 259 goto done; 260 } 261 top = (Uint8 *)surface->pixels; 262 end = (Uint8 *)surface->pixels+(surface->h*surface->pitch); 263 switch (ExpandBMP) { 264 case 1: 265 bmpPitch = (biWidth + 7) >> 3; 266 pad = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0); 267 break; 268 case 4: 269 bmpPitch = (biWidth + 1) >> 1; 270 pad = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0); 271 break; 272 default: 273 pad = ((surface->pitch%4) ? 274 (4-(surface->pitch%4)) : 0); 275 break; 276 } 277 if ( topDown ) { 278 bits = top; 279 } else { 280 bits = end - surface->pitch; 281 } 282 while ( bits >= top && bits < end ) { 283 switch (ExpandBMP) { 284 case 1: 285 case 4: { 286 Uint8 pixel = 0; 287 int shift = (8-ExpandBMP); 288 for ( i=0; i<surface->w; ++i ) { 289 if ( i%(8/ExpandBMP) == 0 ) { 290 if ( !SDL_RWread(src, &pixel, 1, 1) ) { 291 SDL_SetError( 292 "Error reading from BMP"); 293 was_error = SDL_TRUE; 294 goto done; 295 } 296 } 297 *(bits+i) = (pixel>>shift); 298 pixel <<= ExpandBMP; 299 } } 300 break; 301 302 default: 303 if ( SDL_RWread(src, bits, 1, surface->pitch) 304 != surface->pitch ) { 305 SDL_Error(SDL_EFREAD); 306 was_error = SDL_TRUE; 307 goto done; 308 } 309 #if SDL_BYTEORDER == SDL_BIG_ENDIAN 310 /* Byte-swap the pixels if needed. Note that the 24bpp 311 case has already been taken care of above. */ 312 switch(biBitCount) { 313 case 15: 314 case 16: { 315 Uint16 *pix = (Uint16 *)bits; 316 for(i = 0; i < surface->w; i++) 317 pix[i] = SDL_Swap16(pix[i]); 318 break; 319 } 320 321 case 32: { 322 Uint32 *pix = (Uint32 *)bits; 323 for(i = 0; i < surface->w; i++) 324 pix[i] = SDL_Swap32(pix[i]); 325 break; 326 } 327 } 328 #endif 329 break; 330 } 331 /* Skip padding bytes, ugh */ 332 if ( pad ) { 333 Uint8 padbyte; 334 for ( i=0; i<pad; ++i ) { 335 SDL_RWread(src, &padbyte, 1, 1); 336 } 337 } 338 if ( topDown ) { 339 bits += surface->pitch; 340 } else { 341 bits -= surface->pitch; 342 } 343 } 344 done: 345 if ( was_error ) { 346 if ( src ) { 347 SDL_RWseek(src, fp_offset, RW_SEEK_SET); 348 } 349 if ( surface ) { 350 SDL_FreeSurface(surface); 351 } 352 surface = NULL; 353 } 354 if ( freesrc && src ) { 355 SDL_RWclose(src); 356 } 357 return(surface); 358 } 359 360 int SDL_SaveBMP_RW (SDL_Surface *saveme, SDL_RWops *dst, int freedst) 361 { 362 long fp_offset; 363 int i, pad; 364 SDL_Surface *surface; 365 Uint8 *bits; 366 367 /* The Win32 BMP file header (14 bytes) */ 368 char magic[2] = { 'B', 'M' }; 369 Uint32 bfSize; 370 Uint16 bfReserved1; 371 Uint16 bfReserved2; 372 Uint32 bfOffBits; 373 374 /* The Win32 BITMAPINFOHEADER struct (40 bytes) */ 375 Uint32 biSize; 376 Sint32 biWidth; 377 Sint32 biHeight; 378 Uint16 biPlanes; 379 Uint16 biBitCount; 380 Uint32 biCompression; 381 Uint32 biSizeImage; 382 Sint32 biXPelsPerMeter; 383 Sint32 biYPelsPerMeter; 384 Uint32 biClrUsed; 385 Uint32 biClrImportant; 386 387 /* Make sure we have somewhere to save */ 388 surface = NULL; 389 if ( dst ) { 390 if ( saveme->format->palette ) { 391 if ( saveme->format->BitsPerPixel == 8 ) { 392 surface = saveme; 393 } else { 394 SDL_SetError("%d bpp BMP files not supported", 395 saveme->format->BitsPerPixel); 396 } 397 } 398 else if ( (saveme->format->BitsPerPixel == 24) && 399 #if SDL_BYTEORDER == SDL_LIL_ENDIAN 400 (saveme->format->Rmask == 0x00FF0000) && 401 (saveme->format->Gmask == 0x0000FF00) && 402 (saveme->format->Bmask == 0x000000FF) 403 #else 404 (saveme->format->Rmask == 0x000000FF) && 405 (saveme->format->Gmask == 0x0000FF00) && 406 (saveme->format->Bmask == 0x00FF0000) 407 #endif 408 ) { 409 surface = saveme; 410 } else { 411 SDL_Rect bounds; 412 413 /* Convert to 24 bits per pixel */ 414 surface = SDL_CreateRGBSurface(SDL_SWSURFACE, 415 saveme->w, saveme->h, 24, 416 #if SDL_BYTEORDER == SDL_LIL_ENDIAN 417 0x00FF0000, 0x0000FF00, 0x000000FF, 418 #else 419 0x000000FF, 0x0000FF00, 0x00FF0000, 420 #endif 421 0); 422 if ( surface != NULL ) { 423 bounds.x = 0; 424 bounds.y = 0; 425 bounds.w = saveme->w; 426 bounds.h = saveme->h; 427 if ( SDL_LowerBlit(saveme, &bounds, surface, 428 &bounds) < 0 ) { 429 SDL_FreeSurface(surface); 430 SDL_SetError( 431 "Couldn't convert image to 24 bpp"); 432 surface = NULL; 433 } 434 } 435 } 436 } 437 438 if ( surface && (SDL_LockSurface(surface) == 0) ) { 439 const int bw = surface->w*surface->format->BytesPerPixel; 440 441 /* Set the BMP file header values */ 442 bfSize = 0; /* We'll write this when we're done */ 443 bfReserved1 = 0; 444 bfReserved2 = 0; 445 bfOffBits = 0; /* We'll write this when we're done */ 446 447 /* Write the BMP file header values */ 448 fp_offset = SDL_RWtell(dst); 449 SDL_ClearError(); 450 SDL_RWwrite(dst, magic, 2, 1); 451 SDL_WriteLE32(dst, bfSize); 452 SDL_WriteLE16(dst, bfReserved1); 453 SDL_WriteLE16(dst, bfReserved2); 454 SDL_WriteLE32(dst, bfOffBits); 455 456 /* Set the BMP info values */ 457 biSize = 40; 458 biWidth = surface->w; 459 biHeight = surface->h; 460 biPlanes = 1; 461 biBitCount = surface->format->BitsPerPixel; 462 biCompression = BI_RGB; 463 biSizeImage = surface->h*surface->pitch; 464 biXPelsPerMeter = 0; 465 biYPelsPerMeter = 0; 466 if ( surface->format->palette ) { 467 biClrUsed = surface->format->palette->ncolors; 468 } else { 469 biClrUsed = 0; 470 } 471 biClrImportant = 0; 472 473 /* Write the BMP info values */ 474 SDL_WriteLE32(dst, biSize); 475 SDL_WriteLE32(dst, biWidth); 476 SDL_WriteLE32(dst, biHeight); 477 SDL_WriteLE16(dst, biPlanes); 478 SDL_WriteLE16(dst, biBitCount); 479 SDL_WriteLE32(dst, biCompression); 480 SDL_WriteLE32(dst, biSizeImage); 481 SDL_WriteLE32(dst, biXPelsPerMeter); 482 SDL_WriteLE32(dst, biYPelsPerMeter); 483 SDL_WriteLE32(dst, biClrUsed); 484 SDL_WriteLE32(dst, biClrImportant); 485 486 /* Write the palette (in BGR color order) */ 487 if ( surface->format->palette ) { 488 SDL_Color *colors; 489 int ncolors; 490 491 colors = surface->format->palette->colors; 492 ncolors = surface->format->palette->ncolors; 493 for ( i=0; i<ncolors; ++i ) { 494 SDL_RWwrite(dst, &colors[i].b, 1, 1); 495 SDL_RWwrite(dst, &colors[i].g, 1, 1); 496 SDL_RWwrite(dst, &colors[i].r, 1, 1); 497 SDL_RWwrite(dst, &colors[i].unused, 1, 1); 498 } 499 } 500 501 /* Write the bitmap offset */ 502 bfOffBits = SDL_RWtell(dst)-fp_offset; 503 if ( SDL_RWseek(dst, fp_offset+10, RW_SEEK_SET) < 0 ) { 504 SDL_Error(SDL_EFSEEK); 505 } 506 SDL_WriteLE32(dst, bfOffBits); 507 if ( SDL_RWseek(dst, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) { 508 SDL_Error(SDL_EFSEEK); 509 } 510 511 /* Write the bitmap image upside down */ 512 bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch); 513 pad = ((bw%4) ? (4-(bw%4)) : 0); 514 while ( bits > (Uint8 *)surface->pixels ) { 515 bits -= surface->pitch; 516 if ( SDL_RWwrite(dst, bits, 1, bw) != bw) { 517 SDL_Error(SDL_EFWRITE); 518 break; 519 } 520 if ( pad ) { 521 const Uint8 padbyte = 0; 522 for ( i=0; i<pad; ++i ) { 523 SDL_RWwrite(dst, &padbyte, 1, 1); 524 } 525 } 526 } 527 528 /* Write the BMP file size */ 529 bfSize = SDL_RWtell(dst)-fp_offset; 530 if ( SDL_RWseek(dst, fp_offset+2, RW_SEEK_SET) < 0 ) { 531 SDL_Error(SDL_EFSEEK); 532 } 533 SDL_WriteLE32(dst, bfSize); 534 if ( SDL_RWseek(dst, fp_offset+bfSize, RW_SEEK_SET) < 0 ) { 535 SDL_Error(SDL_EFSEEK); 536 } 537 538 /* Close it up.. */ 539 SDL_UnlockSurface(surface); 540 if ( surface != saveme ) { 541 SDL_FreeSurface(surface); 542 } 543 } 544 545 if ( freedst && dst ) { 546 SDL_RWclose(dst); 547 } 548 return((SDL_strcmp(SDL_GetError(), "") == 0) ? 0 : -1); 549 } 550
