Initial Commit

node_modules/color-space/uvw.js

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+/**
+ * https://en.wikipedia.org/wiki/CIE_1964_color_space
+ *
+ * Very similar to LUV, but w and v are calculated a bit differently.
+ *
+ * @module  color-space/uvw
+ */
+import ucs from './ucs.js';
+import xyz from './xyz.js';
+
+var uvw = {
+	name: 'uvw',
+	min: [-134, -140, 0],
+	max: [224, 122, 100],
+	channel: ['U', 'V', 'W'],
+	alias: ['UVW', 'cieuvw', 'cie1964']
+};
+
+export default (uvw);
+
+/**
+ * UVW to XYZ
+ */
+uvw.xyz = function (arg, i, o) {
+	var _u, _v, w, u, v, x, y, z, xn, yn, zn, un, vn;
+	u = arg[0], v = arg[1], w = arg[2];
+
+	if (w === 0) return [0, 0, 0];
+
+	//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 = (6 * yn) / (xn + (15 * yn) + (3 * zn));
+
+	y = Math.pow((w + 17) / 25, 3);
+
+	_u = u / (13 * w) + un || 0;
+	_v = v / (13 * w) + vn || 0;
+
+	x = (6 / 4) * y * _u / _v;
+	z = y * (2 / _v - 0.5 * _u / _v - 5);
+
+	return [x, y, z];
+};
+
+
+/**
+ * XYZ to UVW
+ *
+ * @return {Array<number>} An UVW array
+ */
+xyz.uvw = function (arr, i, o) {
+	var x = arr[0], y = arr[1], z = arr[2], xn, yn, zn, un, vn;
+
+	//find out normal source u v
+	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 = (6 * yn) / (xn + (15 * yn) + (3 * zn));
+
+	var _u = 4 * x / (x + 15 * y + 3 * z) || 0;
+	var _v = 6 * y / (x + 15 * y + 3 * z) || 0;
+
+	//calc values
+	var w = 25 * Math.pow(y, 1 / 3) - 17;
+	var u = 13 * w * (_u - un);
+	var v = 13 * w * (_v - vn);
+
+	return [u, v, w];
+};
+
+
+
+/**
+ * UVW to UCS
+ *
+ * @param {Array<number>} uvw UCS values
+ *
+ * @return {Array<number>} UVW values
+ */
+uvw.ucs = function (uvw) {
+	//find chromacity variables
+	throw new Error('Not implemented');
+};
+
+
+/**
+ * UCS to UVW
+ *
+ * @param {Array<number>} ucs UVW values
+ *
+ * @return {Array<number>} UCS values
+ */
+ucs.uvw = function (ucs) {
+	// //find chromacity variables
+	// var u = U / (U + V + W);
+	// var v = V / (U + V + W);
+
+	// //find 1964 UVW
+	// w = 25 * Math.pow(y, 1/3) - 17;
+	// u = 13 * w * (u - un);
+	// v = 13 * w * (v - vn);
+	throw new Error('Not implemented');
+};