f256/imageconvert/imageconvert.c

/*
 *	Copyright (c) 2024 Scott Duensing, scott@kangaroopunch.com
 *
 *	Permission is hereby granted, free of charge, to any person obtaining a copy
 *	of this software and associated documentation files (the "Software"), to deal
 *	in the Software without restriction, including without limitation the rights
 *	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *	copies of the Software, and to permit persons to whom the Software is
 *	furnished to do so, subject to the following conditions:
 *
 *	The above copyright notice and this permission notice shall be included in
 *	all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 *	SOFTWARE.
 */


#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"


typedef unsigned char byte;

typedef struct colorS {
	byte r;
	byte g;
	byte b;
} colorT;


char *replaceExtension(char *org, char *new_ext) {
	char   *ext;
	char   *tmp     = strdup(org);
	size_t  newSize;
	char   *newName;

	ext = strrchr(tmp , '.');
	if (ext) *ext = 0;

	newSize = strlen(tmp) + strlen(new_ext) + 1;
	newName = malloc(newSize);
	sprintf(newName, "%s%s", tmp, new_ext);

	free(tmp);

	return newName;
}


int main(int argc, char *argv[]) {

	int     x;
	int     y;
	int     w;
	int     h;
	int     n;
	int     colors = 0;
	byte    found;
	byte   *data;
	byte   *p;
	colorT  c;
	colorT  palette[256];
	char   *filename;
	FILE   *out;

	if (argc != 2) {
		printf("Usage:  %s [imagefile]\n", argv[0]);
		return 1;
	}

	data = stbi_load(argv[1], &w, &h, &n, 3);
	if (data == NULL) {
		printf("Unable to load %s!\n", argv[1]);
		return 2;
	}

	// Build palette.
	printf("Building palette...\n");
	p = data;
	for (y=0; y<h; y++) {
		for (x=0; x<w; x++) {
			c.r = *p++;
			c.g = *p++;
			c.b = *p++;
			found = 0;
			for (n=0; n<colors; n++) {
				if ((palette[n].r == c.r) && (palette[n].g == c.g) && (palette[n].b == c.b)) {
					found = 1;
					break;
				}
			}
			if (found == 0) {
				palette[colors].r = c.r;
				palette[colors].g = c.g;
				palette[colors].b = c.b;
				colors++;
				if (colors > 256) {
					free(data);
					printf("More than 256 colors in the image.  Aborting.\n");
					return 3;
				}
			}
		}
	}

	// Write out F256 CLUT.
	filename = replaceExtension(argv[1], ".clut");
	printf("Writing %d color palette %s...\n", colors, filename);
	out = fopen(filename, "wb");
	if (out == NULL) {
		printf("Unable to write %s.  Aborting.\n", filename);
		free(data);
		free(filename);
		return 4;
	}
	for (n=0; n<colors; n++) {
		fputc(palette[n].b, out);
		fputc(palette[n].g, out);
		fputc(palette[n].r, out);
		fputc(0xff, out);
	}
	fclose(out);
	free(filename);

	// Write out raw indexed image.
	filename = replaceExtension(argv[1], ".indexed");
	printf("Writing %dx%d indexed image %s...\n", w, h, filename);
	out = fopen(filename, "wb");
	if (out == NULL) {
		printf("Unable to write %s.  Aborting.\n", filename);
		free(data);
		free(filename);
		return 5;
	}
	p = data;
	for (y=0; y<h; y++) {
		for (x=0; x<w; x++) {
			c.r = *p++;
			c.g = *p++;
			c.b = *p++;
			for (n=0; n<colors; n++) {
				if ((palette[n].r == c.r) && (palette[n].g == c.g) && (palette[n].b == c.b)) {
					fputc(n, out);
					break;
				}
			}
		}
	}
	fclose(out);
	free(filename);

	free(data);

	printf("Finished!\n");

	return 0;
}