rcolor.js

// Free to use & distribute under the MIT license
// Wes Johnson (@SterlingWes)
//
// inspired by http://martin.ankerl.com/2009/12/09/how-to-create-random-colors-programmatically/

(function (root, factory) {
    if (typeof exports === 'object') {
        module.exports = factory;
    } else if (typeof define === 'function' && define.amd) {
        define(factory);
    } else {
        root.RColor = factory();
    }
}(this, function () {

	var RColor = function() {
		this.hue			= Math.random(),
		this.goldenRatio 	= 0.618033988749895;
		this.hexwidth		= 2;
	};

	RColor.prototype.hsvToRgb = function (h,s,v) {
		var	h_i	= Math.floor(h*6),
			f 	= h*6 - h_i,
			p	= v * (1-s),
			q	= v * (1-f*s),
			t	= v * (1-(1-f)*s),
			r	= 255,
			g	= 255,
			b	= 255;
		switch(h_i) {
			case 0:	r = v, g = t, b = p;	break;
			case 1:	r = q, g = v, b = p;	break;
			case 2:	r = p, g = v, b = t;	break;
			case 3:	r = p, g = q, b = v;	break;
			case 4: r = t, g = p, b = v;	break;
			case 5: r = v, g = p, b = q;	break;
		}
		return [Math.floor(r*256),Math.floor(g*256),Math.floor(b*256)];
	};
	
	RColor.prototype.padHex = function(str) {
		if(str.length > this.hexwidth) return str;
		return new Array(this.hexwidth - str.length + 1).join('0') + str;
	};
	
	RColor.prototype.get = function(hex,saturation,value) {
		this.hue += this.goldenRatio;
		this.hue %= 1;
		if(typeof saturation !== "number")	saturation = 0.5;
		if(typeof value !== "number")		value = 0.95;
		var rgb = this.hsvToRgb(this.hue,saturation,value);
		if(hex)
			return "#" +  this.padHex(rgb[0].toString(16))
						+ this.padHex(rgb[1].toString(16))
						+ this.padHex(rgb[2].toString(16));
		else 
			return rgb;
	};

	return RColor;

}));