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 #include <zlib.h> 22 23 #ifndef BOOL 24 #define BOOL unsigned char 25 #endif 26 #ifndef TRUE 27 #define TRUE (BOOL) 1 28 #endif 29 #ifndef FALSE 30 #define FALSE (BOOL) 0 31 #endif 32 33 #ifdef __TURBOC__ 34 #define STDIN 0 35 #define STDOUT 1 36 #define STDERR 2 37 #endif 38 39 /* to make png2pnm verbose so we can find problems (needs to be before png.h) */ 40 #ifndef PNG_DEBUG 41 #define PNG_DEBUG 0 42 #endif 43 44 #include "png.h" 45 46 /* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */ 47 #ifndef png_jmpbuf 48 # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) 49 #endif 50 51 /* function prototypes */ 52 53 int main (int argc, char *argv[]); 54 void usage (); 55 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha); 56 57 /* 58 * main 59 */ 60 61 int main(int argc, char *argv[]) 62 { 63 FILE *fp_rd = stdin; 64 FILE *fp_wr = stdout; 65 FILE *fp_al = NULL; 66 BOOL raw = TRUE; 67 BOOL alpha = FALSE; 68 int argi; 69 70 for (argi = 1; argi < argc; argi++) 71 { 72 if (argv[argi][0] == '-') 73 { 74 switch (argv[argi][1]) 75 { 76 case 'n': 77 raw = FALSE; 78 break; 79 case 'r': 80 raw = TRUE; 81 break; 82 case 'a': 83 alpha = TRUE; 84 argi++; 85 if ((fp_al = fopen (argv[argi], "wb")) == NULL) 86 { 87 fprintf (stderr, "PNM2PNG\n"); 88 fprintf (stderr, "Error: can not create alpha-channel file %s\n", argv[argi]); 89 exit (1); 90 } 91 break; 92 case 'h': 93 case '?': 94 usage(); 95 exit(0); 96 break; 97 default: 98 fprintf (stderr, "PNG2PNM\n"); 99 fprintf (stderr, "Error: unknown option %s\n", argv[argi]); 100 usage(); 101 exit(1); 102 break; 103 } /* end switch */ 104 } 105 else if (fp_rd == stdin) 106 { 107 if ((fp_rd = fopen (argv[argi], "rb")) == NULL) 108 { 109 fprintf (stderr, "PNG2PNM\n"); 110 fprintf (stderr, "Error: file %s does not exist\n", argv[argi]); 111 exit (1); 112 } 113 } 114 else if (fp_wr == stdout) 115 { 116 if ((fp_wr = fopen (argv[argi], "wb")) == NULL) 117 { 118 fprintf (stderr, "PNG2PNM\n"); 119 fprintf (stderr, "Error: can not create file %s\n", argv[argi]); 120 exit (1); 121 } 122 } 123 else 124 { 125 fprintf (stderr, "PNG2PNM\n"); 126 fprintf (stderr, "Error: too many parameters\n"); 127 usage(); 128 exit(1); 129 } 130 } /* end for */ 131 132 #ifdef __TURBOC__ 133 /* set stdin/stdout if required to binary */ 134 if (fp_rd == stdin) 135 { 136 setmode (STDIN, O_BINARY); 137 } 138 if ((raw) && (fp_wr == stdout)) 139 { 140 setmode (STDOUT, O_BINARY); 141 } 142 #endif 143 144 /* call the conversion program itself */ 145 if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE) 146 { 147 fprintf (stderr, "PNG2PNM\n"); 148 fprintf (stderr, "Error: unsuccessful conversion of PNG-image\n"); 149 exit(1); 150 } 151 152 /* close input file */ 153 fclose (fp_rd); 154 /* close output file */ 155 fclose (fp_wr); 156 /* close alpha file */ 157 if (alpha) 158 fclose (fp_al); 159 160 return 0; 161 } 162 163 /* 164 * usage 165 */ 166 167 void usage() 168 { 169 fprintf (stderr, "PNG2PNM\n"); 170 fprintf (stderr, " by Willem van Schaik, 1999\n"); 171 #ifdef __TURBOC__ 172 fprintf (stderr, " for Turbo-C and Borland-C compilers\n"); 173 #else 174 fprintf (stderr, " for Linux (and Unix) compilers\n"); 175 #endif 176 fprintf (stderr, "Usage: png2pnm [options] <file>.png [<file>.pnm]\n"); 177 fprintf (stderr, " or: ... | png2pnm [options]\n"); 178 fprintf (stderr, "Options:\n"); 179 fprintf (stderr, " -r[aw] write pnm-file in binary format (P4/P5/P6) (default)\n"); 180 fprintf (stderr, " -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n"); 181 fprintf (stderr, " -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n"); 182 fprintf (stderr, " -h | -? print this help-information\n"); 183 } 184 185 /* 186 * png2pnm 187 */ 188 189 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha) 190 { 191 png_struct *png_ptr = NULL; 192 png_info *info_ptr = NULL; 193 png_byte buf[8]; 194 png_byte *png_pixels = NULL; 195 png_byte **row_pointers = NULL; 196 png_byte *pix_ptr = NULL; 197 png_uint_32 row_bytes; 198 199 png_uint_32 width; 200 png_uint_32 height; 201 int bit_depth; 202 int channels; 203 int color_type; 204 int alpha_present; 205 int row, col; 206 int ret; 207 int i; 208 long dep_16; 209 210 /* read and check signature in PNG file */ 211 ret = fread (buf, 1, 8, png_file); 212 if (ret != 8) 213 return FALSE; 214 215 ret = png_sig_cmp (buf, 0, 8); 216 if (ret) 217 return FALSE; 218 219 /* create png and info structures */ 220 221 png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, 222 NULL, NULL, NULL); 223 if (!png_ptr) 224 return FALSE; /* out of memory */ 225 226 info_ptr = png_create_info_struct (png_ptr); 227 if (!info_ptr) 228 { 229 png_destroy_read_struct (&png_ptr, NULL, NULL); 230 return FALSE; /* out of memory */ 231 } 232 233 if (setjmp (png_jmpbuf(png_ptr))) 234 { 235 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 236 return FALSE; 237 } 238 239 /* set up the input control for C streams */ 240 png_init_io (png_ptr, png_file); 241 png_set_sig_bytes (png_ptr, 8); /* we already read the 8 signature bytes */ 242 243 /* read the file information */ 244 png_read_info (png_ptr, info_ptr); 245 246 /* get size and bit-depth of the PNG-image */ 247 png_get_IHDR (png_ptr, info_ptr, 248 &width, &height, &bit_depth, &color_type, 249 NULL, NULL, NULL); 250 251 /* set-up the transformations */ 252 253 /* transform paletted images into full-color rgb */ 254 if (color_type == PNG_COLOR_TYPE_PALETTE) 255 png_set_expand (png_ptr); 256 /* expand images to bit-depth 8 (only applicable for grayscale images) */ 257 if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) 258 png_set_expand (png_ptr); 259 /* transform transparency maps into full alpha-channel */ 260 if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS)) 261 png_set_expand (png_ptr); 262 263 #ifdef NJET 264 /* downgrade 16-bit images to 8 bit */ 265 if (bit_depth == 16) 266 png_set_strip_16 (png_ptr); 267 /* transform grayscale images into full-color */ 268 if (color_type == PNG_COLOR_TYPE_GRAY || 269 color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 270 png_set_gray_to_rgb (png_ptr); 271 /* only if file has a file gamma, we do a correction */ 272 if (png_get_gAMA (png_ptr, info_ptr, &file_gamma)) 273 png_set_gamma (png_ptr, (double) 2.2, file_gamma); 274 #endif 275 276 /* all transformations have been registered; now update info_ptr data, 277 * get rowbytes and channels, and allocate image memory */ 278 279 png_read_update_info (png_ptr, info_ptr); 280 281 /* get the new color-type and bit-depth (after expansion/stripping) */ 282 png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, 283 NULL, NULL, NULL); 284 285 /* check for 16-bit files */ 286 if (bit_depth == 16) 287 { 288 raw = FALSE; 289 #ifdef __TURBOC__ 290 pnm_file->flags &= ~((unsigned) _F_BIN); 291 #endif 292 } 293 294 /* calculate new number of channels and store alpha-presence */ 295 if (color_type == PNG_COLOR_TYPE_GRAY) 296 channels = 1; 297 else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) 298 channels = 2; 299 else if (color_type == PNG_COLOR_TYPE_RGB) 300 channels = 3; 301 else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) 302 channels = 4; 303 else 304 channels = 0; /* should never happen */ 305 alpha_present = (channels - 1) % 2; 306 307 /* check if alpha is expected to be present in file */ 308 if (alpha && !alpha_present) 309 { 310 fprintf (stderr, "PNG2PNM\n"); 311 fprintf (stderr, "Error: PNG-file doesn't contain alpha channel\n"); 312 exit (1); 313 } 314 315 /* row_bytes is the width x number of channels x (bit-depth / 8) */ 316 row_bytes = png_get_rowbytes (png_ptr, info_ptr); 317 318 if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) { 319 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 320 return FALSE; 321 } 322 323 if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL) 324 { 325 png_destroy_read_struct (&png_ptr, &info_ptr, NULL); 326 free (png_pixels); 327 png_pixels = NULL; 328 return FALSE; 329 } 330 331 /* set the individual row_pointers to point at the correct offsets */ 332 for (i = 0; i < (height); i++) 333 row_pointers[i] = png_pixels + i * row_bytes; 334 335 /* now we can go ahead and just read the whole image */ 336 png_read_image (png_ptr, row_pointers); 337 338 /* read rest of file, and get additional chunks in info_ptr - REQUIRED */ 339 png_read_end (png_ptr, info_ptr); 340 341 /* clean up after the read, and free any memory allocated - REQUIRED */ 342 png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL); 343 344 /* write header of PNM file */ 345 346 if ((color_type == PNG_COLOR_TYPE_GRAY) || 347 (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) 348 { 349 fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2"); 350 fprintf (pnm_file, "%d %d\n", (int) width, (int) height); 351 fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 352 } 353 else if ((color_type == PNG_COLOR_TYPE_RGB) || 354 (color_type == PNG_COLOR_TYPE_RGB_ALPHA)) 355 { 356 fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3"); 357 fprintf (pnm_file, "%d %d\n", (int) width, (int) height); 358 fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 359 } 360 361 /* write header of PGM file with alpha channel */ 362 363 if ((alpha) && 364 ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) || 365 (color_type == PNG_COLOR_TYPE_RGB_ALPHA))) 366 { 367 fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2"); 368 fprintf (alpha_file, "%d %d\n", (int) width, (int) height); 369 fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L)); 370 } 371 372 /* write data to PNM file */ 373 pix_ptr = png_pixels; 374 375 for (row = 0; row < height; row++) 376 { 377 for (col = 0; col < width; col++) 378 { 379 for (i = 0; i < (channels - alpha_present); i++) 380 { 381 if (raw) 382 fputc ((int) *pix_ptr++ , pnm_file); 383 else 384 if (bit_depth == 16){ 385 dep_16 = (long) *pix_ptr++; 386 fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++)); 387 } 388 else 389 fprintf (pnm_file, "%ld ", (long) *pix_ptr++); 390 } 391 if (alpha_present) 392 { 393 if (!alpha) 394 { 395 pix_ptr++; /* alpha */ 396 if (bit_depth == 16) 397 pix_ptr++; 398 } 399 else /* output alpha-channel as pgm file */ 400 { 401 if (raw) 402 fputc ((int) *pix_ptr++ , alpha_file); 403 else 404 if (bit_depth == 16){ 405 dep_16 = (long) *pix_ptr++; 406 fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++); 407 } 408 else 409 fprintf (alpha_file, "%ld ", (long) *pix_ptr++); 410 } 411 } /* if alpha_present */ 412 413 if (!raw) 414 if (col % 4 == 3) 415 fprintf (pnm_file, "\n"); 416 } /* end for col */ 417 418 if (!raw) 419 if (col % 4 != 0) 420 fprintf (pnm_file, "\n"); 421 } /* end for row */ 422 423 if (row_pointers != (unsigned char**) NULL) 424 free (row_pointers); 425 if (png_pixels != (unsigned char*) NULL) 426 free (png_pixels); 427 428 return TRUE; 429 430 } /* end of source */ 431 432
