Initial Commit

node_modules/color-space/luv.js

@@ -0,0 +1,100 @@
+/**
+ * CIE LUV (C'est la vie)
+ *
+ * @module color-space/luv
+ */
+import xyz from './xyz.js';
+
+var luv = {
+	name: 'luv',
+	//NOTE: luv has no rigidly defined limits
+	//easyrgb fails to get proper coords
+	//boronine states no rigid limits
+	//colorMine refers this ones:
+	min: [0, -134, -140],
+	max: [100, 224, 122],
+	channel: ['lightness', 'u', 'v'],
+	alias: ['LUV', 'cieluv', 'cie1976'],
+
+	xyz: function (arg, i, o) {
+		var _u, _v, l, u, v, x, y, z, xn, yn, zn, un, vn;
+		l = arg[0], u = arg[1], v = arg[2];
+
+		if (l === 0) return [0, 0, 0];
+
+		//get constants
+		//var e = 0.008856451679035631; //(6/29)^3
+		var k = 0.0011070564598794539; //(3/29)^3
+
+		//get illuminant/observer
+		i = i || 'D65';
+		o = o || 2;
+
+		xn = xyz.whitepoint[o][i][0];
+		yn = xyz.whitepoint[o][i][1];
+		zn = xyz.whitepoint[o][i][2];
+
+		un = (4 * xn) / (xn + (15 * yn) + (3 * zn));
+		vn = (9 * yn) / (xn + (15 * yn) + (3 * zn));
+		// un = 0.19783000664283;
+		// vn = 0.46831999493879;
+
+
+		_u = u / (13 * l) + un || 0;
+		_v = v / (13 * l) + vn || 0;
+
+		y = l > 8 ? yn * Math.pow((l + 16) / 116, 3) : yn * l * k;
+
+		//wikipedia method
+		x = y * 9 * _u / (4 * _v) || 0;
+		z = y * (12 - 3 * _u - 20 * _v) / (4 * _v) || 0;
+
+		//boronine method
+		//https://github.com/boronine/husl/blob/master/husl.coffee#L201
+		// x = 0 - (9 * y * _u) / ((_u - 4) * _v - _u * _v);
+		// z = (9 * y - (15 * _v * y) - (_v * x)) / (3 * _v);
+
+		return [x, y, z];
+	}
+};
+
+export default (luv);
+
+// http://www.brucelindbloom.com/index.html?Equations.html
+// https://github.com/boronine/husl/blob/master/husl.coffee
+//i - illuminant
+//o - observer
+xyz.luv = function (arg, i, o) {
+	var _u, _v, l, u, v, x, y, z, xn, yn, zn, un, vn;
+
+	//get constants
+	var e = 0.008856451679035631; //(6/29)^3
+	var k = 903.2962962962961; //(29/3)^3
+
+	//get illuminant/observer coords
+	i = i || 'D65';
+	o = o || 2;
+
+	xn = xyz.whitepoint[o][i][0];
+	yn = xyz.whitepoint[o][i][1];
+	zn = xyz.whitepoint[o][i][2];
+
+	un = (4 * xn) / (xn + (15 * yn) + (3 * zn));
+	vn = (9 * yn) / (xn + (15 * yn) + (3 * zn));
+
+
+	x = arg[0], y = arg[1], z = arg[2];
+
+
+	_u = (4 * x) / (x + (15 * y) + (3 * z)) || 0;
+	_v = (9 * y) / (x + (15 * y) + (3 * z)) || 0;
+
+	var yr = y / yn;
+
+	l = yr <= e ? k * yr : 116 * Math.pow(yr, 1 / 3) - 16;
+
+	u = 13 * l * (_u - un);
+	v = 13 * l * (_v - vn);
+
+	return [l, u, v];
+};