1 /* 2 * png2pnm.c --- conversion from PNG-file to PGM/PPM-file 3 * copyright (C) 1999 by Willem van Schaik <willem (at) schaik.com> 4 * 5 * version 1.0 - 1999.10.15 - First version. 6 * 7 * Permission to use, copy, modify, and distribute this software and 8 * its documentation for any purpose and without fee is hereby granted, 9 * provided that the above copyright notice appear in all copies and 10 * that both that copyright notice and this permission notice appear in 11 * supporting documentation. This software is provided "as is" without 12 * express or implied warranty. 13 */ 14 15 #include <stdio.h> 16 #include <stdlib.h> 17 #ifdef __TURBOC__ 18 #include <mem.h> 19 #include <fcntl.h> 20 #endif 21 22 #ifndef BOOL 23 #define BOOL unsigned char 24 #endif 25 #ifndef TRUE 26 #define TRUE (BOOL) 1 27 #endif 28 #ifndef FALSE 29 #define FALSE (BOOL) 0 30 #endif 31 32 #ifdef __TURBOC__ 33 #define STDIN 0 34 #define STDOUT 1 35 #define STDERR 2 36 #endif 37 38 /* to make png2pnm verbose so we can find problems (needs to be before png.h) */ 39 #ifndef PNG_DEBUG 40 #define PNG_DEBUG 0 41 #endif 42 43 #include "png.h" 44 45 /* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */ 46 #ifndef png_jmpbuf 47 # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) 48 #endif 49 50 /* function prototypes */ 51 52 int main (int argc, char *argv[]); 53 void usage (); 54 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha); 55 56 /* 57 * main 58 */ 59 60 int main(int argc, char *argv[]) 61 { 62 FILE *fp_rd = stdin; 63 FILE *fp_wr = stdout; 64 FILE *fp_al = NULL; 65 BOOL raw = TRUE; 66 BOOL alpha = FALSE; 67 int argi; 68 69 for (argi = 1; argi < argc; argi++) 70 { 71 if (argv[argi][0] == '-') 72 { 73 switch (argv[argi][1]) 74 { 75 case 'n': 76 raw = FALSE; 77 break; 78 case 'r': 79 raw = TRUE; 80 break; 81 case 'a': 82 alpha = TRUE; 83 argi++; 84 if ((fp_al = fopen (argv[argi], "wb")) == NULL) 85 { 86 fprintf (stderr, "PNM2PNG\n"); 87 fprintf (stderr, "Error: can not create alpha-channel file %s\n", argv[argi]); 88 exit (1); 89 } 90 break; 91 case 'h': 92 case '?': 93 usage(); 94 exit(0); 95 break; 96 default: 97 fprintf (stderr, "PNG2PNM\n"); 98 fprintf (stderr, "Error: unknown option %s\n", argv[argi]); 99 usage(); 100 exit(1); 101 break; 102 } /* end switch */ 103 } 104 else if (fp_rd == stdin) 105 { 106 if ((fp_rd = fopen (argv[argi], "rb")) == NULL) 107 { 108 fprintf (stderr, "PNG2PNM\n"); 109 fprintf (stderr, "Error: file %s does not exist\n", argv[argi]); 110 exit (1); 111 } 112 } 113 else if (fp_wr == stdout) 114 { 115 if ((fp_wr = fopen (argv[argi], "wb")) == NULL) 116 { 117 fprintf (stderr, "PNG2PNM\n"); 118 fprintf (stderr, "Error: can not create file %s\n", argv[argi]); 119 exit (1); 120 } 121 } 122 else 123 { 124 fprintf (stderr, "PNG2PNM\n"); 125 fprintf (stderr, "Error: too many parameters\n"); 126 usage(); 127 exit(1); 128 } 129 } /* end for */ 130 131 #ifdef __TURBOC__ 132 /* set stdin/stdout if required to binary */ 133 if (fp_rd == stdin) 134 { 135 setmode (STDIN, O_BINARY); 136 } 137 if ((raw) && (fp_wr == stdout)) 138 { 139 setmode (STDOUT, O_BINARY); 140 } 141 #endif 142 143 /* call the conversion program itself */ 144 if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE) 145 { 146 fprintf (stderr, "PNG2PNM\n"); 147 fprintf (stderr, "Error: unsuccessful convertion of PNG-image\n"); 148 exit(1); 149 } 150 151 /* close input file */ 152 fclose (fp_rd); 153 /* close output file */ 154 fclose (fp_wr); 155 /* close alpha file */ 156 if (alpha) 157 fclose (fp_al); 158 159 return 0; 160 } 161 162 /* 163 * usage 164 */ 165 166 void usage() 167 { 168 fprintf (stderr, "PNG2PNM\n"); 169 fprintf (stderr, " by Willem van Schaik, 1999\n"); 170 #ifdef __TURBOC__ 171 fprintf (stderr, " for Turbo-C and Borland-C compilers\n"); 172 #else 173 fprintf (stderr, " for Linux (and Unix) compilers\n"); 174 #endif 175 fprintf (stderr, "Usage: png2pnm [options] <file>.png [<file>.pnm]\n"); 176 fprintf (stderr, " or: ... | png2pnm [options]\n"); 177 fprintf (stderr, "Options:\n"); 178 fprintf (stderr, " -r[aw] write pnm-file in binary format (P4/P5/P6) (default)\n"); 179 fprintf (stderr, " -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n"); 180 fprintf (stderr, " -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n"); 181 fprintf (stderr, " -h | -? print this help-information\n"); 182 } 183 184 /* 185 * png2pnm 186 */ 187 188 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha) 189 { 190 png_struct *png_ptr = NULL; 191 png_info *info_ptr = NULL; 192 png_byte buf[8]; 193 png_byte *png_pixels = NULL; 194 png_byte **row_pointers = NULL; 195 png_byte *pix_ptr = NULL; 196 png_uint_32 row_bytes; 197 198 png_uint_32 width; 199 png_uint_32 height; 200 int bit_depth; 201 int channels; 202 int color_type; 203 int alpha_present; 204 int row, col; 205 int ret; 206 int i; 207 long dep_16; 208 209 /* read and check signature in PNG file */ 210 ret = fread (buf, 1, 8, png_file); 211 if (ret != 8) 212 return FALSE; 213 214 ret = !png_sig_cmp (buf, 0, 8); 215 if (!ret) 216 return FALSE; 217 218 /* create png and info structures */ 219 220 png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, 221 NULL, NULL, NULL); 222 if (!png_ptr) 223 return FALSE; /* out of memory */ 224 225 info_ptr = png_create_info_struct (png_ptr); 226 if (!info_ptr) 227 { 228 png_destroy_read_struct (&png_ptr, NULL, NULL); 229 return FALSE; /* out of memory */ 230 } 231 232 if (setjmp (png_jmpbuf(png_ptr))) 233 { 234 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 235 return FALSE; 236 } 237 238 /* set up the input control for C streams */ 239 png_init_io (png_ptr, png_file); 240 png_set_sig_bytes (png_ptr, 8); /* we already read the 8 signature bytes */ 241 242 /* read the file information */ 243 png_read_info (png_ptr, info_ptr); 244 245 /* get size and bit-depth of the PNG-image */ 246 png_get_IHDR (png_ptr, info_ptr, 247 &width, &height, &bit_depth, &color_type, 248 NULL, NULL, NULL); 249 250 /* set-up the transformations */ 251 252 /* transform paletted images into full-color rgb */ 253 if (color_type == PNG_COLOR_TYPE_PALETTE) 254 png_set_expand (png_ptr); 255 /* expand images to bit-depth 8 (only applicable for grayscale images) */ 256 if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) 257 png_set_expand (png_ptr); 258 /* transform transparency maps into full alpha-channel */ 259 if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS)) 260 png_set_expand (png_ptr); 261 262 #ifdef NJET 263 /* downgrade 16-bit images to 8 bit */ 264 if (bit_depth == 16) 265 png_set_strip_16 (png_ptr); 266 /* transform grayscale images into full-color */ 267 if (color_type == PNG_COLOR_TYPE_GRAY || 268 color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 269 png_set_gray_to_rgb (png_ptr); 270 /* only if file has a file gamma, we do a correction */ 271 if (png_get_gAMA (png_ptr, info_ptr, &file_gamma)) 272 png_set_gamma (png_ptr, (double) 2.2, file_gamma); 273 #endif 274 275 /* all transformations have been registered; now update info_ptr data, 276 * get rowbytes and channels, and allocate image memory */ 277 278 png_read_update_info (png_ptr, info_ptr); 279 280 /* get the new color-type and bit-depth (after expansion/stripping) */ 281 png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, 282 NULL, NULL, NULL); 283 284 /* check for 16-bit files */ 285 if (bit_depth == 16) 286 { 287 raw = FALSE; 288 #ifdef __TURBOC__ 289 pnm_file->flags &= ~((unsigned) _F_BIN); 290 #endif 291 } 292 293 /* calculate new number of channels and store alpha-presence */ 294 if (color_type == PNG_COLOR_TYPE_GRAY) 295 channels = 1; 296 else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 297 channels = 2; 298 else if (color_type == PNG_COLOR_TYPE_RGB) 299 channels = 3; 300 else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) 301 channels = 4; 302 else 303 channels = 0; /* should never happen */ 304 alpha_present = (channels - 1) % 2; 305 306 /* check if alpha is expected to be present in file */ 307 if (alpha && !alpha_present) 308 { 309 fprintf (stderr, "PNG2PNM\n"); 310 fprintf (stderr, "Error: PNG-file doesn't contain alpha channel\n"); 311 exit (1); 312 } 313 314 /* row_bytes is the width x number of channels x (bit-depth / 8) */ 315 row_bytes = png_get_rowbytes (png_ptr, info_ptr); 316 317 if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) { 318 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 319 return FALSE; 320 } 321 322 if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL) 323 { 324 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 325 free (png_pixels); 326 png_pixels = NULL; 327 return FALSE; 328 } 329 330 /* set the individual row_pointers to point at the correct offsets */ 331 for (i = 0; i < (height); i++) 332 row_pointers[i] = png_pixels + i * row_bytes; 333 334 /* now we can go ahead and just read the whole image */ 335 png_read_image (png_ptr, row_pointers); 336 337 /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ 338 png_read_end (png_ptr, info_ptr); 339 340 /* clean up after the read, and free any memory allocated - REQUIRED */ 341 png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL); 342 343 /* write header of PNM file */ 344 345 if ((color_type == PNG_COLOR_TYPE_GRAY) || 346 (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) 347 { 348 fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2"); 349 fprintf (pnm_file, "%d %d\n", (int) width, (int) height); 350 fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 351 } 352 else if ((color_type == PNG_COLOR_TYPE_RGB) || 353 (color_type == PNG_COLOR_TYPE_RGB_ALPHA)) 354 { 355 fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3"); 356 fprintf (pnm_file, "%d %d\n", (int) width, (int) height); 357 fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 358 } 359 360 /* write header of PGM file with alpha channel */ 361 362 if ((alpha) && 363 ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) || 364 (color_type == PNG_COLOR_TYPE_RGB_ALPHA))) 365 { 366 fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2"); 367 fprintf (alpha_file, "%d %d\n", (int) width, (int) height); 368 fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 369 } 370 371 /* write data to PNM file */ 372 pix_ptr = png_pixels; 373 374 for (row = 0; row < height; row++) 375 { 376 for (col = 0; col < width; col++) 377 { 378 for (i = 0; i < (channels - alpha_present); i++) 379 { 380 if (raw) 381 fputc ((int) *pix_ptr++ , pnm_file); 382 else 383 if (bit_depth == 16){ 384 dep_16 = (long) *pix_ptr++; 385 fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++)); 386 } 387 else 388 fprintf (pnm_file, "%ld ", (long) *pix_ptr++); 389 } 390 if (alpha_present) 391 { 392 if (!alpha) 393 { 394 pix_ptr++; /* alpha */ 395 if (bit_depth == 16) 396 pix_ptr++; 397 } 398 else /* output alpha-channel as pgm file */ 399 { 400 if (raw) 401 fputc ((int) *pix_ptr++ , alpha_file); 402 else 403 if (bit_depth == 16){ 404 dep_16 = (long) *pix_ptr++; 405 fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++); 406 } 407 else 408 fprintf (alpha_file, "%ld ", (long) *pix_ptr++); 409 } 410 } /* if alpha_present */ 411 412 if (!raw) 413 if (col % 4 == 3) 414 fprintf (pnm_file, "\n"); 415 } /* end for col */ 416 417 if (!raw) 418 if (col % 4 != 0) 419 fprintf (pnm_file, "\n"); 420 } /* end for row */ 421 422 if (row_pointers != (unsigned char**) NULL) 423 free (row_pointers); 424 if (png_pixels != (unsigned char*) NULL) 425 free (png_pixels); 426 427 return TRUE; 428 429 } /* end of source */ 430 431
