/* This script and many more are available free online at
The JavaScript Source!! http://javascript.internet.com
Created by: Joseph Myers | http://www.codelib.net/
http://www.scriptsearch.com/details/11381.html
*/

var maxColor = parseInt('ff', 16);

function colorscale(hexstr, scalefactor) {
/* declared variables first, in order;
	afterwards, undeclared local variables */
	var r = scalefactor;
	var a, i;
	if (r < 0 || typeof(hexstr) != 'string')
		return hexstr;
		hexstr = hexstr.replace(/[^0-9a-f]+/ig, '');
		if (hexstr.length == 3) {
		a = hexstr.split('');
	} else if (hexstr.length == 6) {
		a = hexstr.match(/(\w{2})/g);
	} else
		return hexstr;
	for (i=0; i<a.length; i++) {
		if (a[i].length == 2)
			a[i] = parseInt(a[i], 16);
		else {
			a[i] = parseInt(a[i], 16);
			a[i] = a[i]*16 + a[i];
	}
}

function relsize(a) {
	if (a == maxColor)
	return Infinity;
	return a/(maxColor-a);
}

function relsizeinv(y) {
	if (y == Infinity)
	return maxColor;
	return maxColor*y/(1+y);
}

for (i=0; i<a.length; i++) {
	a[i] = relsizeinv(relsize(a[i])*r);
	a[i] = Math.floor(a[i]).toString(16);
	if (a[i].length == 1)
	a[i] = '0' + a[i];
}
return a.join('');
}

function showrainbow(f) {
	var colorcell, hex, i, nhex;
	hex = f.orig.value;
	hex = hex.replace(/\W/g, '');
	nhex = colorscale(hex, f.scalef.value-0);
	if (nhex != hex) {
		f.outp.value = nhex;
		colorcell = document.getElementById('origcolor');
		i = document.getElementById('newcolor');
		colorcell.style.background = '#' + hex;
		i.style.background = '#' + nhex;
		for (i=0; i<256; i++) {
			colorcell = document.getElementById('colorcell'+i);
			nhex = colorscale(hex, i/(256-i));
			colorcell.style.background = '#' + nhex;
			colorcell.nhexvalue = nhex;
		}
	}
}