/*
* 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_sig_cmp (buf, 0, 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 */