/* *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com> * *  version 1.0 - 1999.10.15 - First version. * *  Permission to use, copy, modify, and distribute this software and *  its documentation for any purpose and without fee is hereby granted, *  provided that the above copyright notice appear in all copies and *  that both that copyright notice and this permission notice appear in *  supporting documentation. This software is provided "as is" without *  express or implied warranty. */#include <stdio.h>#include <stdlib.h>#ifdef __TURBOC__#include <mem.h>#include <fcntl.h>#endif#ifndef BOOL#define BOOL unsigned char#endif#ifndef TRUE#define TRUE (BOOL) 1#endif#ifndef FALSE#define FALSE (BOOL) 0#endif#ifdef __TURBOC__#define STDIN  0#define STDOUT 1#define STDERR 2#endif/* to make png2pnm verbose so we can find problems (needs to be before png.h) */#ifndef PNG_DEBUG#define PNG_DEBUG 0#endif#include "png.h"/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */#ifndef png_jmpbuf#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)#endif/* function prototypes */int  main (int argc, char *argv[]);void usage ();BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);/* *  main */int main(int argc, char *argv[]){  FILE *fp_rd = stdin;  FILE *fp_wr = stdout;  FILE *fp_al = NULL;  BOOL raw = TRUE;  BOOL alpha = FALSE;  int argi;  for (argi = 1; argi < argc; argi++)  {    if (argv[argi][0] == '-')    {      switch (argv[argi][1])      {        case 'n':          raw = FALSE;          break;        case 'r':          raw = TRUE;          break;        case 'a':          alpha = TRUE;          argi++;          if ((fp_al = fopen (argv[argi], "wb")) == NULL)          {            fprintf (stderr, "PNM2PNG\n");            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);            exit (1);          }          break;        case 'h':        case '?':          usage();          exit(0);          break;        default:          fprintf (stderr, "PNG2PNM\n");          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);          usage();          exit(1);          break;      } /* end switch */    }    else if (fp_rd == stdin)    {      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)      {             fprintf (stderr, "PNG2PNM\n");            fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);            exit (1);      }    }    else if (fp_wr == stdout)    {      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)      {        fprintf (stderr, "PNG2PNM\n");        fprintf (stderr, "Error:  can not create file %s\n", argv[argi]);        exit (1);      }    }    else    {      fprintf (stderr, "PNG2PNM\n");      fprintf (stderr, "Error:  too many parameters\n");      usage();      exit(1);    }  } /* end for */#ifdef __TURBOC__  /* set stdin/stdout if required to binary */  if (fp_rd == stdin)  {    setmode (STDIN, O_BINARY);  }  if ((raw) && (fp_wr == stdout))  {    setmode (STDOUT, O_BINARY);  }#endif  /* call the conversion program itself */  if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)  {    fprintf (stderr, "PNG2PNM\n");    fprintf (stderr, "Error:  unsuccessful convertion of PNG-image\n");    exit(1);  }  /* close input file */  fclose (fp_rd);  /* close output file */  fclose (fp_wr);  /* close alpha file */  if (alpha)    fclose (fp_al);  return 0;}/* *  usage */void usage(){  fprintf (stderr, "PNG2PNM\n");  fprintf (stderr, "   by Willem van Schaik, 1999\n");#ifdef __TURBOC__  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");#else  fprintf (stderr, "   for Linux (and Unix) compilers\n");#endif  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");  fprintf (stderr, "   or:  ... | png2pnm [options]\n");  fprintf (stderr, "Options:\n");  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");  fprintf (stderr, "   -h | -?  print this help-information\n");}/* *  png2pnm */BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha){  png_struct    *png_ptr = NULL;  png_info	*info_ptr = NULL;  png_byte      buf[8];  png_byte      *png_pixels = NULL;  png_byte      **row_pointers = NULL;  png_byte      *pix_ptr = NULL;  png_uint_32   row_bytes;  png_uint_32   width;  png_uint_32   height;  int           bit_depth;  int           channels;  int           color_type;  int           alpha_present;  int           row, col;  int           ret;  int           i;  long          dep_16;  /* read and check signature in PNG file */  ret = fread (buf, 1, 8, png_file);  if (ret != 8)    return FALSE;  ret = png_check_sig (buf, 8);  if (!ret)    return FALSE;  /* create png and info structures */  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,    NULL, NULL, NULL);  if (!png_ptr)    return FALSE;   /* out of memory */  info_ptr = png_create_info_struct (png_ptr);  if (!info_ptr)  {    png_destroy_read_struct (&png_ptr, NULL, NULL);    return FALSE;   /* out of memory */  }  if (setjmp (png_jmpbuf(png_ptr)))  {    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);    return FALSE;  }  /* set up the input control for C streams */  png_init_io (png_ptr, png_file);  png_set_sig_bytes (png_ptr, 8);  /* we already read the 8 signature bytes */  /* read the file information */  png_read_info (png_ptr, info_ptr);  /* get size and bit-depth of the PNG-image */  png_get_IHDR (png_ptr, info_ptr,    &width, &height, &bit_depth, &color_type,    NULL, NULL, NULL);  /* set-up the transformations */  /* transform paletted images into full-color rgb */  if (color_type == PNG_COLOR_TYPE_PALETTE)    png_set_expand (png_ptr);  /* expand images to bit-depth 8 (only applicable for grayscale images) */  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)    png_set_expand (png_ptr);  /* transform transparency maps into full alpha-channel */  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))    png_set_expand (png_ptr);#ifdef NJET  /* downgrade 16-bit images to 8 bit */  if (bit_depth == 16)    png_set_strip_16 (png_ptr);  /* transform grayscale images into full-color */  if (color_type == PNG_COLOR_TYPE_GRAY ||    color_type == PNG_COLOR_TYPE_GRAY_ALPHA)    png_set_gray_to_rgb (png_ptr);  /* only if file has a file gamma, we do a correction */  if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))    png_set_gamma (png_ptr, (double) 2.2, file_gamma);#endif  /* all transformations have been registered; now update info_ptr data,   * get rowbytes and channels, and allocate image memory */  png_read_update_info (png_ptr, info_ptr);  /* get the new color-type and bit-depth (after expansion/stripping) */  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,    NULL, NULL, NULL);  /* check for 16-bit files */  if (bit_depth == 16)  {    raw = FALSE;#ifdef __TURBOC__    pnm_file->flags &= ~((unsigned) _F_BIN);#endif  }  /* calculate new number of channels and store alpha-presence */  if (color_type == PNG_COLOR_TYPE_GRAY)    channels = 1;  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)    channels = 2;  else if (color_type == PNG_COLOR_TYPE_RGB)    channels = 3;  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)    channels = 4;  else    channels = 0; /* should never happen */  alpha_present = (channels - 1) % 2;  /* check if alpha is expected to be present in file */  if (alpha && !alpha_present)  {    fprintf (stderr, "PNG2PNM\n");    fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");    exit (1);  }  /* row_bytes is the width x number of channels x (bit-depth / 8) */  row_bytes = png_get_rowbytes (png_ptr, info_ptr);  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) {    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);    return FALSE;  }  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)  {    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);    free (png_pixels);    png_pixels = NULL;    return FALSE;  }  /* set the individual row_pointers to point at the correct offsets */  for (i = 0; i < (height); i++)    row_pointers[i] = png_pixels + i * row_bytes;  /* now we can go ahead and just read the whole image */  png_read_image (png_ptr, row_pointers);  /* read rest of file, and get additional chunks in info_ptr - REQUIRED */  png_read_end (png_ptr, info_ptr);  /* clean up after the read, and free any memory allocated - REQUIRED */  png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL);  /* write header of PNM file */  if ((color_type == PNG_COLOR_TYPE_GRAY) ||      (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))  {    fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));  }  else if ((color_type == PNG_COLOR_TYPE_RGB) ||           (color_type == PNG_COLOR_TYPE_RGB_ALPHA))  {    fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));  }  /* write header of PGM file with alpha channel */  if ((alpha) &&      ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||       (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))  {    fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");    fprintf (alpha_file, "%d %d\n", (int) width, (int) height);    fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));  }  /* write data to PNM file */  pix_ptr = png_pixels;  for (row = 0; row < height; row++)  {    for (col = 0; col < width; col++)    {      for (i = 0; i < (channels - alpha_present); i++)      {        if (raw)          fputc ((int) *pix_ptr++ , pnm_file);        else          if (bit_depth == 16){	    dep_16 = (long) *pix_ptr++;            fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));          }          else            fprintf (pnm_file, "%ld ", (long) *pix_ptr++);      }      if (alpha_present)      {        if (!alpha)        {          pix_ptr++; /* alpha */          if (bit_depth == 16)            pix_ptr++;        }        else /* output alpha-channel as pgm file */        {          if (raw)            fputc ((int) *pix_ptr++ , alpha_file);          else            if (bit_depth == 16){	      dep_16 = (long) *pix_ptr++;              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);	    }              else              fprintf (alpha_file, "%ld ", (long) *pix_ptr++);        }      } /* if alpha_present */      if (!raw)        if (col % 4 == 3)          fprintf (pnm_file, "\n");    } /* end for col */    if (!raw)      if (col % 4 != 0)        fprintf (pnm_file, "\n");  } /* end for row */  if (row_pointers != (unsigned char**) NULL)    free (row_pointers);  if (png_pixels != (unsigned char*) NULL)    free (png_pixels);  return TRUE;} /* end of source */