various color conversion functions

Color conversion

function hsv2hex(hsv) {
	return rgb2hex(hsv2rgb(hsv));
}

function hex2hsv(hex) {
	var dec = hex2dec(hex);
	var rgb = dec2rgb(dec);
	var hsv = rgb2hsv(rgb);
	return hsv;
}

function hsl2hex(hsl) {
	var rgb = hsl2rgb(hsl);
	var hex = rgb2hex(rgb);
	return hex;
}

function hex2hsl(hex) {
	var dec = hex2dec(hex);
	var rgb = dec2rgb(dec);
	var hsl = rgb2hsl(rgb);
	return hsl;
}

function rgb2hsv(rgb){
	var r = rgb[0] / 255;
	var g = rgb[1] / 255;
	var b = rgb[2] / 255;
	var max = Math.max(r, g, b), min = Math.min(r, g, b);
	var h, s, v = max;
	var d = max - min;
	s = max == 0 ? 0 : d / max;
	if(max == min) {
		h = 0;
	} else {
		switch(max){
			case r: h = (g - b) / d + (g < b ? 6 : 0); break;
			case g: h = (b - r) / d + 2; break;
			case b: h = (r - g) / d + 4; break;
		}
		h /= 6;
	}
	return [h, s, v];
}

function dec2rgb(dec) {
	var r = dec >> 16 & 255;
	var g = dec >> 8 & 255;
	var b = dec & 255;
	return [r,g,b];
}

function dec2hex(dec, padding) {
	var hex = "";
	if(dec == 0)  {
		hex = "0";
	} else {
		while(dec) {
			var b = dec & 0xf;
			hex = (b < 10 ? b : String.fromCharCode(b + 87)) + hex;
			dec = dec >> 4;
		}
	}
	var padder = "0000000000";
	return (padder + hex).substr(padder.length - padding + hex.length, padding);
}


function hex2dec(hex) {
	var dec = parseInt(hex, 16);
	return dec;
}
	
function hsv2rgb(hsv) {
	var h = hsv[0];
	var s = hsv[1];
	var v = hsv[2];
	var r, g, b;
	var i = Math.floor(h * 6);
	var f = h * 6 - i;
	var p = v * (1 - s);
	var q = v * (1 - f * s);
	var t = v * (1 - (1 - f) * s);
	switch(i % 6){
		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.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
}

function rgb2hex(rgb) {
	rgb[0] = Math.round(rgb[0]);
	rgb[1] = Math.round(rgb[1]);
	rgb[2] = Math.round(rgb[2]);
	function h(i) {
		var code = i + 48 + (i > 9 ? 7 : 0);
		return String.fromCharCode(code);
	}
	var hex = h(rgb[0] >> 4) + h(rgb[0] % 16)
			+ h(rgb[1] >> 4) + h(rgb[1] % 16)
			+ h(rgb[2] >> 4) + h(rgb[2] % 16);
	return hex;
}

// from https://github.com/cloudhead/less.js
function hsl2rgb(hsl) {
	var h = (hsl[0] % 360) / 360,
		s = hsl[1],
		l = hsl[2];
		var m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
	var m1 = l * 2 - m2;
	return [hue(h + 1/3) * 255, hue(h) * 255, hue(h - 1/3) * 255];

	function hue(h) {
		h = h < 0 ? h + 1 : (h > 1 ? h - 1 : h);
		if (h * 6 < 1) 		return m1 + (m2 - m1) * h * 6;
		else if (h * 2 < 1) return m2;
		else if (h * 3 < 2) return m1 + (m2 - m1) * (2/3 - h) * 6;
		else				return m1;
	}
}

function rgb2hsl(rgb) {
	var r = rgb[0] / 255,
		g = rgb[1] / 255,
		b = rgb[2] / 255;
	var max = Math.max(r, g, b), min = Math.min(r, g, b);
	var h, s, l = (max + min) / 2, d = max - min;
	if (max === min) {
		h = s = 0;
	} else {
		s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
		switch (max) {
			case r: h = (g - b) / d + (g < b ? 6 : 0); break;
			case g: h = (b - r) / d + 2;               break;
			case b: h = (r - g) / d + 4;               break;
		}
		h /= 6;
	}
	return [h * 360, s, l];
}