HsvToRgb.js

/**
 * HSV to RGB color conversion
 *
 * H runs from 0 to 360 degrees
 * S and V run from 0 to 100
 * 
 * Ported from the excellent java algorithm by Eugene Vishnevsky at:
 * http://www.cs.rit.edu/~ncs/color/t_convert.html
 * from : http://snipplr.com/view/14590/hsv-to-rgb/
 */
function hsvToRgb(h, s, v) {
	var r, g, b;
	var i;
	var f, p, q, t;
 
	// Make sure our arguments stay in-range
	h = Math.max(0, Math.min(360, h));
	s = Math.max(0, Math.min(100, s));
	v = Math.max(0, Math.min(100, v));
 
	// We accept saturation and value arguments from 0 to 100 because that's
	// how Photoshop represents those values. Internally, however, the
	// saturation and value are calculated from a range of 0 to 1. We make
	// That conversion here.
	s /= 100;
	v /= 100;
 
	if(s == 0) {
		// Achromatic (grey)
		r = g = b = v;
		return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
	}
 
	h /= 60; // sector 0 to 5
	i = Math.floor(h);
	f = h - i; // factorial part of h
	p = v * (1 - s);
	q = v * (1 - s * f);
	t = v * (1 - s * (1 - f));
 
	switch(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;
 
		default: // case 5:
			r = v;
			g = p;
			b = q;
	}
 
	return {r: r, g: g, b: b};
}