Initial Commit

node_modules/color-space/hwb.js

@@ -0,0 +1,109 @@
+/**
+ * @module color-space/hwb
+ */
+import rgb from './rgb.js';
+import hsv from './hsv.js';
+import hsl from './hsl.js';
+
+var hwb = {
+	name: 'hwb',
+	min: [0, 0, 0],
+	max: [360, 100, 100],
+	channel: ['hue', 'whiteness', 'blackness'],
+	alias: ['HWB'],
+
+	// http://dev.w3.org/csswg/css-color/#hwb-to-rgb
+	rgb: function (hwb) {
+		var h = hwb[0] / 360,
+			wh = hwb[1] / 100,
+			bl = hwb[2] / 100,
+			ratio = wh + bl,
+			i, v, f, n;
+
+		var r, g, b;
+
+		// wh + bl cant be > 1
+		if (ratio > 1) {
+			wh /= ratio;
+			bl /= ratio;
+		}
+
+		i = Math.floor(6 * h);
+		v = 1 - bl;
+		f = 6 * h - i;
+
+		//if it is even
+		if ((i & 0x01) !== 0) {
+			f = 1 - f;
+		}
+
+		n = wh + f * (v - wh);  // linear interpolation
+
+		switch (i) {
+			default:
+			case 6:
+			case 0: r = v; g = n; b = wh; break;
+			case 1: r = n; g = v; b = wh; break;
+			case 2: r = wh; g = v; b = n; break;
+			case 3: r = wh; g = n; b = v; break;
+			case 4: r = n; g = wh; b = v; break;
+			case 5: r = v; g = wh; b = n; break;
+		}
+
+		return [r * 255, g * 255, b * 255];
+	},
+
+
+	// http://alvyray.com/Papers/CG/HWB_JGTv208.pdf
+	hsv: function (arg) {
+		var h = arg[0], w = arg[1], b = arg[2], s, v;
+
+		//if w+b > 100% - take proportion (how many times )
+		if (w + b >= 100) {
+			s = 0;
+			v = 100 * w / (w + b);
+		}
+
+		//by default - take wiki formula
+		else {
+			s = 100 - (w / (1 - b / 100));
+			v = 100 - b;
+		}
+
+
+		return [h, s, v];
+	},
+
+	hsl: function (arg) {
+		return hsv.hsl(hwb.hsv(arg));
+	}
+};
+
+export default (hwb);
+
+
+// extend rgb
+rgb.hwb = function (val) {
+	var r = val[0],
+		g = val[1],
+		b = val[2],
+		h = rgb.hsl(val)[0],
+		w = 1 / 255 * Math.min(r, Math.min(g, b));
+
+	b = 1 - 1 / 255 * Math.max(r, Math.max(g, b));
+
+	return [h, w * 100, b * 100];
+};
+
+
+// keep proper hue on 0 values (conversion to rgb loses hue on zero-lightness)
+hsv.hwb = function (arg) {
+	var h = arg[0], s = arg[1], v = arg[2];
+	return [h, v === 0 ? 0 : (v * (1 - s / 100)), 100 - v];
+};
+
+
+//extend hsl with proper conversions
+hsl.hwb = function (arg) {
+	return hsv.hwb(hsl.hsv(arg));
+};