initial commit. phase 1 complete

frontend/node_modules/culori/src/luv/convertLuvToXyz50.js

@@ -0,0 +1,25 @@
+import { k } from '../xyz50/constants.js';
+import { D50 } from '../constants.js';
+
+export const u_fn = (x, y, z) => (4 * x) / (x + 15 * y + 3 * z);
+export const v_fn = (x, y, z) => (9 * y) / (x + 15 * y + 3 * z);
+
+export const un = u_fn(D50.X, D50.Y, D50.Z);
+export const vn = v_fn(D50.X, D50.Y, D50.Z);
+
+const convertLuvToXyz50 = ({ l, u, v, alpha }) => {
+	let up = u / (13 * l) + un;
+	let vp = v / (13 * l) + vn;
+	let y = D50.Y * (l <= 8 ? l / k : Math.pow((l + 16) / 116, 3));
+	let x = (y * (9 * up)) / (4 * vp);
+	let z = (y * (12 - 3 * up - 20 * vp)) / (4 * vp);
+
+	let res = { mode: 'xyz50', x, y, z };
+	if (alpha !== undefined) {
+		res.alpha = alpha;
+	}
+
+	return res;
+};
+
+export default convertLuvToXyz50;