1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/palette.c	Tue Jun 19 06:48:38 2012 +0300
     1.3 @@ -0,0 +1,145 @@
     1.4 +/*
     1.5 +A simple interactive mandelbrot fractal explorer
     1.6 +Copyright (C) John Tsiombikas <nuclear@member.fsf.org>
     1.7 +
     1.8 +This program is free software: you can redistribute it and/or modify
     1.9 +it under the terms of the GNU General Public License as published by
    1.10 +the Free Software Foundation, either version 3 of the License, or
    1.11 +(at your option) any later version.
    1.12 +
    1.13 +This program is distributed in the hope that it will be useful,
    1.14 +but WITHOUT ANY WARRANTY; without even the implied warranty of
    1.15 +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    1.16 +GNU General Public License for more details.
    1.17 +
    1.18 +You should have received a copy of the GNU General Public License
    1.19 +along with this program.  If not, see <http://www.gnu.org/licenses/>.
    1.20 +*/
    1.21 +#include <stdio.h>
    1.22 +#include <stdlib.h>
    1.23 +#include <string.h>
    1.24 +#include <errno.h>
    1.25 +#include "palette.h"
    1.26 +
    1.27 +struct palnode {
    1.28 +	double t;
    1.29 +	double r, g, b;
    1.30 +	struct palnode *next;
    1.31 +};
    1.32 +
    1.33 +static void fill_palette(struct palnode *list);
    1.34 +static void free_list(struct palnode *list);
    1.35 +
    1.36 +int load_palette(const char *fname)
    1.37 +{
    1.38 +	FILE *fp;
    1.39 +	int res;
    1.40 +
    1.41 +	if(!(fp = fopen(fname, "r"))) {
    1.42 +		fprintf(stderr, "failed to open palette file: %s: %s\n", fname, strerror(errno));
    1.43 +		return -1;
    1.44 +	}
    1.45 +	res = load_palette_file(fp);
    1.46 +	fclose(fp);
    1.47 +	return res;
    1.48 +}
    1.49 +
    1.50 +int load_palette_file(FILE *fp)
    1.51 +{
    1.52 +	char buf[256];
    1.53 +	struct palnode *palist = 0, *patail = 0;
    1.54 +
    1.55 +	if(!fgets(buf, sizeof buf, fp) || strstr(buf, "GRAD") != buf) {
    1.56 +		fprintf(stderr, "invalid palette file, lack of magic!\n");
    1.57 +		return -1;
    1.58 +	}
    1.59 +
    1.60 +	while(fgets(buf, sizeof buf, fp)) {
    1.61 +		struct palnode *node;
    1.62 +		float t, r, g, b;
    1.63 +
    1.64 +		if(sscanf(buf, "%f %f %f %f", &t, &r, &g, &b) != 4) {
    1.65 +			fprintf(stderr, "invalid palette file format\n");
    1.66 +			free_list(palist);
    1.67 +			return -1;
    1.68 +		}
    1.69 +
    1.70 +		if(!(node = malloc(sizeof *node))) {
    1.71 +			fprintf(stderr, "failed to allocate memory for list node\n");
    1.72 +			free_list(palist);
    1.73 +			return -1;
    1.74 +		}
    1.75 +		node->t = t;
    1.76 +		node->r = r;
    1.77 +		node->g = g;
    1.78 +		node->b = b;
    1.79 +		node->next = 0;
    1.80 +
    1.81 +		if(palist) {
    1.82 +			patail->next = node;
    1.83 +			patail = node;
    1.84 +		} else {
    1.85 +			palist = patail = node;
    1.86 +		}
    1.87 +	}
    1.88 +
    1.89 +	fill_palette(palist);
    1.90 +	free_list(palist);
    1.91 +	return 0;
    1.92 +}
    1.93 +
    1.94 +static void fill_palette(struct palnode *list)
    1.95 +{
    1.96 +	int i;
    1.97 +	struct palnode *start, *end;
    1.98 +	static const struct palnode last = {1.0, 0.0, 0.0, 0.0, 0};
    1.99 +
   1.100 +	memset(palette, 0, sizeof palette);
   1.101 +	if(!list) {
   1.102 +		return;
   1.103 +	}
   1.104 +
   1.105 +	start = list;
   1.106 +	end = list->next;
   1.107 +
   1.108 +	while(start && start != &last) {
   1.109 +		int sidx, eidx, count;
   1.110 +		double r, g, b, dr, dg, db;
   1.111 +
   1.112 +		if(!end) {
   1.113 +			end = (struct palnode*)&last;
   1.114 +		}
   1.115 +
   1.116 +		sidx = (int)(start->t * PAL_SIZE);
   1.117 +		eidx = (int)(end->t * PAL_SIZE);
   1.118 +		count = eidx - sidx;
   1.119 +
   1.120 +		r = start->r;
   1.121 +		g = start->g;
   1.122 +		b = start->b;
   1.123 +		dr = (end->r - start->r) / count;
   1.124 +		dg = (end->g - start->g) / count;
   1.125 +		db = (end->b - start->b) / count;
   1.126 +
   1.127 +		for(i=0; i<count; i++) {
   1.128 +			palette[sidx + i].r = (int)(r * 255.0);
   1.129 +			palette[sidx + i].g = (int)(g * 255.0);
   1.130 +			palette[sidx + i].b = (int)(b * 255.0);
   1.131 +			r += dr;
   1.132 +			g += dg;
   1.133 +			b += db;
   1.134 +		}
   1.135 +
   1.136 +		start = end;
   1.137 +		end = end->next;
   1.138 +	}
   1.139 +}
   1.140 +
   1.141 +static void free_list(struct palnode *list)
   1.142 +{
   1.143 +	while(list) {
   1.144 +		void *tmp = list;
   1.145 +		list = list->next;
   1.146 +		free(tmp);
   1.147 +	}
   1.148 +}