#include <stdio.h>
#include <stdlib.h> /* For atoi */
#include "gd.h"

/* A short program which converts a .png file into a .gd file, for
	your convenience in creating images on the fly from a
	basis image that must be loaded quickly. The .gd format
	is not intended to be a general-purpose format. */

int main(int argc, char **argv)
{
	gdImagePtr im;
	FILE *in, *out;
	int x, y, w, h;

	if (argc != 7) {
		fprintf(stderr, "Usage: gdparttopng filename.gd filename.png x y w h\n");
		exit(1);
	}
	in = fopen(argv[1], "rb");
	if (!in) {
		fprintf(stderr, "Input file does not exist!\n");
		exit(1);
	}

	x = atoi(argv[3]);
	y = atoi(argv[4]);
        w = atoi(argv[5]);
        h = atoi(argv[6]);

	printf("Extracting from (%d, %d), size is %dx%d\n", x, y, w, h);

	im = gdImageCreateFromGd2Part(in, x, y, w, h);
	fclose(in);
	if (!im) {
		fprintf(stderr, "Input is not in PNG format!\n");
		exit(1);
	}
	out = fopen(argv[2], "wb");
	if (!out) {
		fprintf(stderr, "Output file cannot be written to!\n");
		gdImageDestroy(im);
		exit(1);	
	}
        gdImagePng(im, out);
	fclose(out);
	gdImageDestroy(im);

	return 0;
}