share/png/contrib/pngminus/png2pnm.c

   1 /*
   2  *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
   3  *  copyright (C) 1999 by Willem van Schaik <willem@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