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

/* 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 GD2 format!\n");
        exit(1);
    }
    out = fopen(argv[2], "wb");
    if (!out) {
        fprintf(stderr, "Output file cannot be written to!\n");
        gdImageDestroy(im);
        exit(1);
    }
#ifdef HAVE_LIBPNG
    gdImagePng(im, out);
#else
    fprintf(stderr, "No PNG library support.\n");
#endif
    fclose(out);
    gdImageDestroy(im);

    return 0;
}
