src/bmp.cpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file bmp.cpp Read and write support for bmps. */
  11
  12 #include "stdafx.h"
  13 #include "bmp.h"
  14 #include "core/bitmath_func.hpp"
  15 #include "core/alloc_func.hpp"
  16 #include "core/mem_func.hpp"
  17
  18 void BmpInitializeBuffer(BmpBuffer *buffer, FILE *file)
  19 {
  20         buffer->pos      = -1;
  21         buffer->file     = file;
  22         buffer->read     = 0;
  23         buffer->real_pos = ftell(file);
  24 }
  25
  26 static inline void AdvanceBuffer(BmpBuffer *buffer)
  27 {
  28         if (buffer->read < 0) return;
  29
  30         buffer->read = (int)fread(buffer->data, 1, BMP_BUFFER_SIZE, buffer->file);
  31         buffer->pos  = 0;
  32 }
  33
  34 static inline bool EndOfBuffer(BmpBuffer *buffer)
  35 {
  36         if (buffer->read < 0) return false;
  37
  38         if (buffer->pos == buffer->read || buffer->pos < 0) AdvanceBuffer(buffer);
  39         return buffer->pos == buffer->read;
  40 }
  41
  42 static inline byte ReadByte(BmpBuffer *buffer)
  43 {
  44         if (buffer->read < 0) return 0;
  45
  46         if (buffer->pos == buffer->read || buffer->pos < 0) AdvanceBuffer(buffer);
  47         buffer->real_pos++;
  48         return buffer->data[buffer->pos++];
  49 }
  50
  51 static inline uint16 ReadWord(BmpBuffer *buffer)
  52 {
  53         uint16 var = ReadByte(buffer);
  54         return var | (ReadByte(buffer) << 8);
  55 }
  56
  57 static inline uint32 ReadDword(BmpBuffer *buffer)
  58 {
  59         uint32 var = ReadWord(buffer);
  60         return var | (ReadWord(buffer) << 16);
  61 }
  62
  63 static inline void SkipBytes(BmpBuffer *buffer, int bytes)
  64 {
  65         int i;
  66         for (i = 0; i < bytes; i++) ReadByte(buffer);
  67 }
  68
  69 static inline void SetStreamOffset(BmpBuffer *buffer, int offset)
  70 {
  71         if (fseek(buffer->file, offset, SEEK_SET) < 0) {
  72                 buffer->read = -1;
  73         }
  74         buffer->pos = -1;
  75         buffer->real_pos = offset;
  76         AdvanceBuffer(buffer);
  77 }
  78
  79 /**
  80  * Reads a 1 bpp uncompressed bitmap
  81  * The bitmap is converted to a 8 bpp bitmap
  82  */
  83 static inline bool BmpRead1(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
  84 {
  85         uint x, y, i;
  86         byte pad = GB(4 - info->width / 8, 0, 2);
  87         byte *pixel_row;
  88         byte b;
  89         for (y = info->height; y > 0; y--) {
  90                 x = 0;
  91                 pixel_row = &data->bitmap[(y - 1) * info->width];
  92                 while (x < info->width) {
  93                         if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
  94                         b = ReadByte(buffer);
  95                         for (i = 8; i > 0; i--) {
  96                                 if (x < info->width) *pixel_row++ = GB(b, i - 1, 1);
  97                                 x++;
  98                         }
  99                 }
 100                 /* Padding for 32 bit align */
 101                 SkipBytes(buffer, pad);
 102         }
 103         return true;
 104 }
 105
 106 /**
 107  * Reads a 4 bpp uncompressed bitmap
 108  * The bitmap is converted to a 8 bpp bitmap
 109  */
 110 static inline bool BmpRead4(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 111 {
 112         uint x, y;
 113         byte pad = GB(4 - info->width / 2, 0, 2);
 114         byte *pixel_row;
 115         byte b;
 116         for (y = info->height; y > 0; y--) {
 117                 x = 0;
 118                 pixel_row = &data->bitmap[(y - 1) * info->width];
 119                 while (x < info->width) {
 120                         if (EndOfBuffer(buffer)) return false;  // the file is shorter than expected
 121                         b = ReadByte(buffer);
 122                         *pixel_row++ = GB(b, 4, 4);
 123                         x++;
 124                         if (x < info->width) {
 125                                 *pixel_row++ = GB(b, 0, 4);
 126                                 x++;
 127                         }
 128                 }
 129                 /* Padding for 32 bit align */
 130                 SkipBytes(buffer, pad);
 131         }
 132         return true;
 133 }
 134
 135 /**
 136  * Reads a 4-bit RLE compressed bitmap
 137  * The bitmap is converted to a 8 bpp bitmap
 138  */
 139 static inline bool BmpRead4Rle(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 140 {
 141         uint x = 0;
 142         uint y = info->height - 1;
 143         byte *pixel = &data->bitmap[y * info->width];
 144         while (y != 0 || x < info->width) {
 145                 if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 146
 147                 byte n = ReadByte(buffer);
 148                 byte c = ReadByte(buffer);
 149                 if (n == 0) {
 150                         switch (c) {
 151                                 case 0: // end of line
 152                                         x = 0;
 153                                         if (y == 0) return false;
 154                                         pixel = &data->bitmap[--y * info->width];
 155                                         break;
 156
 157                                 case 1: // end of bitmap
 158                                         return true;
 159
 160                                 case 2: { // delta
 161                                         if (EndOfBuffer(buffer)) return false;
 162                                         byte dx = ReadByte(buffer);
 163                                         byte dy = ReadByte(buffer);
 164
 165                                         /* Check for over- and underflow. */
 166                                         if (x + dx >= info->width || x + dx < x || dy > y) return false;
 167
 168                                         x += dx;
 169                                         y -= dy;
 170                                         pixel = &data->bitmap[y * info->width + x];
 171                                         break;
 172                                 }
 173
 174                                 default: { // uncompressed
 175                                         uint i = 0;
 176                                         while (i++ < c) {
 177                                                 if (EndOfBuffer(buffer) || x >= info->width) return false;
 178                                                 byte b = ReadByte(buffer);
 179                                                 *pixel++ = GB(b, 4, 4);
 180                                                 x++;
 181                                                 if (i++ < c) {
 182                                                         if (x >= info->width) return false;
 183                                                         *pixel++ = GB(b, 0, 4);
 184                                                         x++;
 185                                                 }
 186                                         }
 187                                         /* Padding for 16 bit align */
 188                                         SkipBytes(buffer, ((c + 1) / 2) % 2);
 189                                         break;
 190                                 }
 191                         }
 192                 } else {
 193                         /* Apparently it is common to encounter BMPs where the count of
 194                          * pixels to be written is higher than the remaining line width.
 195                          * Ignore the superfluous pixels instead of reporting an error. */
 196                         uint i = 0;
 197                         while (x < info->width && i++ < n) {
 198                                 *pixel++ = GB(c, 4, 4);
 199                                 x++;
 200                                 if (x < info->width && i++ < n) {
 201                                         *pixel++ = GB(c, 0, 4);
 202                                         x++;
 203                                 }
 204                         }
 205                 }
 206         }
 207         return true;
 208 }
 209
 210 /**
 211  * Reads a 8 bpp bitmap
 212  */
 213 static inline bool BmpRead8(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 214 {
 215         uint i;
 216         uint y;
 217         byte pad = GB(4 - info->width, 0, 2);
 218         byte *pixel;
 219         for (y = info->height; y > 0; y--) {
 220                 if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 221                 pixel = &data->bitmap[(y - 1) * info->width];
 222                 for (i = 0; i < info->width; i++) *pixel++ = ReadByte(buffer);
 223                 /* Padding for 32 bit align */
 224                 SkipBytes(buffer, pad);
 225         }
 226         return true;
 227 }
 228
 229 /**
 230  * Reads a 8-bit RLE compressed bpp bitmap
 231  */
 232 static inline bool BmpRead8Rle(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 233 {
 234         uint x = 0;
 235         uint y = info->height - 1;
 236         byte *pixel = &data->bitmap[y * info->width];
 237         while (y != 0 || x < info->width) {
 238                 if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 239
 240                 byte n = ReadByte(buffer);
 241                 byte c = ReadByte(buffer);
 242                 if (n == 0) {
 243                         switch (c) {
 244                                 case 0: // end of line
 245                                         x = 0;
 246                                         if (y == 0) return false;
 247                                         pixel = &data->bitmap[--y * info->width];
 248                                         break;
 249
 250                                 case 1: // end of bitmap
 251                                         return true;
 252
 253                                 case 2: { // delta
 254                                         if (EndOfBuffer(buffer)) return false;
 255                                         byte dx = ReadByte(buffer);
 256                                         byte dy = ReadByte(buffer);
 257
 258                                         /* Check for over- and underflow. */
 259                                         if (x + dx >= info->width || x + dx < x || dy > y) return false;
 260
 261                                         x += dx;
 262                                         y -= dy;
 263                                         pixel = &data->bitmap[y * info->width + x];
 264                                         break;
 265                                 }
 266
 267                                 default: { // uncompressed
 268                                         for (uint i = 0; i < c; i++) {
 269                                                 if (EndOfBuffer(buffer) || x >= info->width) return false;
 270                                                 *pixel++ = ReadByte(buffer);
 271                                                 x++;
 272                                         }
 273                                         /* Padding for 16 bit align */
 274                                         SkipBytes(buffer, c % 2);
 275                                         break;
 276                                 }
 277                         }
 278                 } else {
 279                         /* Apparently it is common to encounter BMPs where the count of
 280                          * pixels to be written is higher than the remaining line width.
 281                          * Ignore the superfluous pixels instead of reporting an error. */
 282                         for (uint i = 0; x < info->width && i < n; i++) {
 283                                 *pixel++ = c;
 284                                 x++;
 285                         }
 286                 }
 287         }
 288         return true;
 289 }
 290
 291 /**
 292  * Reads a 24 bpp uncompressed bitmap
 293  */
 294 static inline bool BmpRead24(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 295 {
 296         uint x, y;
 297         byte pad = GB(4 - info->width * 3, 0, 2);
 298         byte *pixel_row;
 299         for (y = info->height; y > 0; y--) {
 300                 pixel_row = &data->bitmap[(y - 1) * info->width * 3];
 301                 for (x = 0; x < info->width; x++) {
 302                         if (EndOfBuffer(buffer)) return false; // the file is shorter than expected
 303                         *(pixel_row + 2) = ReadByte(buffer); // green
 304                         *(pixel_row + 1) = ReadByte(buffer); // blue
 305                         *pixel_row       = ReadByte(buffer); // red
 306                         pixel_row += 3;
 307                 }
 308                 /* Padding for 32 bit align */
 309                 SkipBytes(buffer, pad);
 310         }
 311         return true;
 312 }
 313
 314 /*
 315  * Reads bitmap headers, and palette (if any)
 316  */
 317 bool BmpReadHeader(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 318 {
 319         uint32 header_size;
 320         assert(info != NULL);
 321         MemSetT(info, 0);
 322
 323         /* Reading BMP header */
 324         if (ReadWord(buffer) != 0x4D42) return false; // signature should be 'BM'
 325         SkipBytes(buffer, 8); // skip file size and reserved
 326         info->offset = ReadDword(buffer);
 327
 328         /* Reading info header */
 329         header_size = ReadDword(buffer);
 330         if (header_size < 12) return false; // info header should be at least 12 bytes long
 331
 332         info->os2_bmp = (header_size == 12); // OS/2 1.x or windows 2.x info header is 12 bytes long
 333
 334         if (info->os2_bmp) {
 335                 info->width = ReadWord(buffer);
 336                 info->height = ReadWord(buffer);
 337                 header_size -= 8;
 338         } else {
 339                 info->width = ReadDword(buffer);
 340                 info->height = ReadDword(buffer);
 341                 header_size -= 12;
 342         }
 343
 344         if (ReadWord(buffer) != 1) return false; // BMP can have only 1 plane
 345
 346         info->bpp = ReadWord(buffer);
 347         if (info->bpp != 1 && info->bpp != 4 && info->bpp != 8 && info->bpp != 24) {
 348                 /* Only 1 bpp, 4 bpp, 8bpp and 24 bpp bitmaps are supported */
 349                 return false;
 350         }
 351
 352         /* Reads compression method if available in info header*/
 353         if ((header_size -= 4) >= 4) {
 354                 info->compression = ReadDword(buffer);
 355                 header_size -= 4;
 356         }
 357
 358         /* Only 4-bit and 8-bit rle compression is supported */
 359         if (info->compression > 2 || (info->compression > 0 && !(info->bpp == 4 || info->bpp == 8))) return false;
 360
 361         if (info->bpp <= 8) {
 362                 uint i;
 363
 364                 /* Reads number of colours if available in info header */
 365                 if (header_size >= 16) {
 366                         SkipBytes(buffer, 12);                  // skip image size and resolution
 367                         info->palette_size = ReadDword(buffer); // number of colours in palette
 368                         SkipBytes(buffer, header_size - 16);    // skip the end of info header
 369                 }
 370                 if (info->palette_size == 0) info->palette_size = 1 << info->bpp;
 371
 372                 data->palette = xcalloct<Colour>(info->palette_size);
 373
 374                 for (i = 0; i < info->palette_size; i++) {
 375                         data->palette[i].b = ReadByte(buffer);
 376                         data->palette[i].g = ReadByte(buffer);
 377                         data->palette[i].r = ReadByte(buffer);
 378                         if (!info->os2_bmp) SkipBytes(buffer, 1); // unused
 379                 }
 380         }
 381
 382         return buffer->real_pos <= info->offset;
 383 }
 384
 385 /*
 386  * Reads the bitmap
 387  * 1 bpp and 4 bpp bitmaps are converted to 8 bpp bitmaps
 388  */
 389 bool BmpReadBitmap(BmpBuffer *buffer, BmpInfo *info, BmpData *data)
 390 {
 391         assert(info != NULL && data != NULL);
 392
 393         data->bitmap = xcalloct<byte>(info->width * info->height * ((info->bpp == 24) ? 3 : 1));
 394
 395         /* Load image */
 396         SetStreamOffset(buffer, info->offset);
 397         switch (info->compression) {
 398         case 0: // no compression
 399                 switch (info->bpp) {
 400                 case 1:  return BmpRead1(buffer, info, data);
 401                 case 4:  return BmpRead4(buffer, info, data);
 402                 case 8:  return BmpRead8(buffer, info, data);
 403                 case 24: return BmpRead24(buffer, info, data);
 404                 default: NOT_REACHED();
 405                 }
 406         case 1:  return BmpRead8Rle(buffer, info, data); // 8-bit RLE compression
 407         case 2:  return BmpRead4Rle(buffer, info, data); // 4-bit RLE compression
 408         default: NOT_REACHED();
 409         }
 410 }
 411
 412 void BmpDestroyData(BmpData *data)
 413 {
 414         assert(data != NULL);
 415         free(data->palette);
 416         free(data->bitmap);
 417 }