hsv.js

/**
 * @module color-space/hsv
 */
import rgb from './rgb.js';
import hsl from './hsl.js';

export default {
	name: 'hsv',
	min: [0,0,0],
	max: [360,100,100],
	channel: ['hue', 'saturation', 'value'],
	alias: ['HSV', 'HSB'],

	rgb: function(hsv) {
		var h = hsv[0] / 60,
			s = hsv[1] / 100,
			v = hsv[2] / 100,
			hi = Math.floor(h) % 6;

		var f = h - Math.floor(h),
			p = 255 * v * (1 - s),
			q = 255 * v * (1 - (s * f)),
			t = 255 * v * (1 - (s * (1 - f)));
		v *= 255;

		switch(hi) {
			case 0:
				return [v, t, p];
			case 1:
				return [q, v, p];
			case 2:
				return [p, v, t];
			case 3:
				return [p, q, v];
			case 4:
				return [t, p, v];
			case 5:
				return [v, p, q];
		}
	},

	hsl: function(hsv) {
		var h = hsv[0],
			s = hsv[1] / 100,
			v = hsv[2] / 100,
			sl, l;

		l = (2 - s) * v;
		sl = s * v;
		sl /= (l <= 1) ? l : 2 - l;
		sl = sl || 0;
		l /= 2;

		return [h, sl * 100, l * 100];
	}
};


//append rgb
rgb.hsv = function(rgb) {
	var r = rgb[0],
		g = rgb[1],
		b = rgb[2],
		min = Math.min(r, g, b),
		max = Math.max(r, g, b),
		delta = max - min,
		h, s, v;

	if (max === 0) {
		s = 0;
	}
	else {
		s = (delta/max * 100);
	}

	if (max === min) {
		h = 0;
	}
	else if (r === max) {
		h = (g - b) / delta;
	}
	else if (g === max) {
		h = 2 + (b - r) / delta;
	}
	else if (b === max) {
		h = 4 + (r - g) / delta;
	}

	h = Math.min(h * 60, 360);

	if (h < 0) {
		h += 360;
	}

	v = ((max / 255) * 1000) / 10;

	return [h, s, v];
};



//extend hsl
hsl.hsv = function(hsl) {
	var h = hsl[0],
			s = hsl[1] / 100,
			l = hsl[2] / 100,
			sv, v;
	l *= 2;
	s *= (l <= 1) ? l : 2 - l;
	v = (l + s) / 2;
	sv = (2 * s) / (l + s) || 0;

	return [h, sv * 100, v * 100];
};