/* Create color scale for use in Tk programs
 *	set colorscale   [split [exec Tk_colorscale -s.7 -n10] " "]
 *  command line options:
 *	-d	decimal output for humans
 *	-m	color map: rainbow, purple, gray, terrain, iron, astro, zebra
 *	-n	number of colors
 *	-r	reverse the order
 *	-s	saturation (between 0 and 1)
 *
 * The author of this software is Eric Grosse. Copyright (c) 1993 by AT&T.
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software and in all copies of the supporting
 * documentation for such software.
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR AT&T MAKE ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 */

/* The following is defined in ftp://netlib.att.com/netlib/graphics/rainbow.c */
extern void rainbow(double h, double s, double v, double *r, double *g, double *b);

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <math.h>
extern int getopt(int,char**,char*); /* POSIX.2 unistd.h */
extern char *optarg;  extern int optind;

/* color maps */
#define RAINBOW	1
#define GRAY	2
#define TERRAIN	3
#define IRON	4
#define ASTRO	5
#define ZEBRA	6
#define PURPLE	7

int
mapstr(char *s)
{
	if(strcmp(s,"rainbow")==0) return(RAINBOW);
	if(strcmp(s,"purple")==0) return(PURPLE);
	if(strcmp(s,"gray")==0 || strcmp(s,"grey")==0) return(GRAY);
	if(strcmp(s,"terrain")==0 || strcmp(s,"topo")==0) return(TERRAIN);
	if(strcmp(s,"iron")==0 || strncmp(s,"hot",3)==0) return(IRON);
	if(strcmp(s,"astro")==0) return(ASTRO);
	if(strcmp(s,"zebra")==0) return(ZEBRA);
	fprintf(stderr,"color choices: rainbow, purple, gray, terrain, iron, astro, zebra\n");
	return(RAINBOW);
}

void
main(int argc, char**argv)
{
	int	r, g, b, reverse = 0, map, ncolors = 11, ihue, decimal = 0;
	double	hue, sat = .99, red, green, blue, h;

	map = RAINBOW;
	{int c;while((c=getopt(argc,argv,"dm:n:rs:"))!=-1)switch(c){
		case 'd':	decimal = 1-decimal; break;
		case 'm':	map = mapstr(optarg); break;
		case 'n':	ncolors = atoi(optarg); break;
		case 'r':	reverse = 1-reverse; break;
		case 's':	sat = atof(optarg); break;
	}}
	if(sat>0.99) sat = 0.99;
	for(ihue = 0; ihue < ncolors; ihue++){
		hue = ((double)ihue)/(ncolors-1);
		if(hue>1.) hue = 1.;
		if(reverse) hue = 1.-hue;
		switch(map){
		  case RAINBOW:
			rainbow(1.-hue, sat, 1., &red, &green, &blue);
			break;
		  case PURPLE:
			rainbow(1.5*(1.-hue), sat, 1., &red, &green, &blue);
			break;
		  case GRAY:
			red = hue;
			green = hue;
			blue = hue;
			break;
		  case TERRAIN:
			h = 3*hue;
			if(h<.25){
				red = 0;
				green = 0;
				blue = 0.25+2*h;
			}else if(h<2){
				red = 0;
				green = 0.25+(2-h);
				blue = 0;
			}else if(h<2.7){
				red = .75;
				green = .15;
				blue = .0;
			}else{
				red = .9;
				green = .9;
				blue = .9;
			}
			break;
		  case IRON:
			red = 3*(hue+.03);
			green = 3*(hue-.333333);
			blue = 3*(hue-.666667);
			break;
		  case ASTRO:
			red = hue;
			green = hue;
			blue = (hue+.2)/1.2;
			break;
		  case ZEBRA:
			red = (ihue+reverse) % 2;
			green = red;
			blue = red;
		}
		if(red>1.) red = 1.;
		if(green>1.) green = 1.;
		if(blue>1.) blue = 1.;
		if(red<0.) red = 0.;
		if(green<0.) green = 0.;
		if(blue<0.) blue = 0.;
		r = 255*red;
		g = 255*green;
		b = 255*blue;
		printf(decimal?" %d,%d,%d":" #%02x%02x%02x",r,g,b);
		if(ihue%20==19 && ihue!=ncolors-1)
			printf("\n");
	}
	printf("\n");
	exit(0);
}