First Commit

node_modules/culori/src/okhsl/convertOkhslToOklab.js

@@ -0,0 +1,62 @@
+/*
+	Adapted from code by Björn Ottosson,
+	released under the MIT license:
+
+	Copyright (c) 2021 Björn Ottosson
+
+	Permission is hereby granted, free of charge, to any person obtaining a copy of
+	this software and associated documentation files (the "Software"), to deal in
+	the Software without restriction, including without limitation the rights to
+	use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+	of the Software, and to permit persons to whom the Software is furnished to do
+	so, subject to the following conditions:
+
+	The above copyright notice and this permission notice shall be included in all
+	copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	SOFTWARE.
+ */
+
+import { toe_inv, get_Cs } from './helpers.js';
+
+export default function convertOkhslToOklab(hsl) {
+	let l = toe_inv(hsl.l);
+
+	const ret = { mode: 'oklab', l };
+
+	if (hsl.alpha !== undefined) {
+		ret.alpha = hsl.alpha;
+	}
+
+	if (!hsl.s || hsl.l === 1) {
+		ret.a = ret.b = 0;
+		return ret;
+	}
+
+	let a_ = Math.cos((hsl.h / 180) * Math.PI);
+	let b_ = Math.sin((hsl.h / 180) * Math.PI);
+	let [C_0, C_mid, C_max] = get_Cs(l, a_, b_);
+	let t, k_0, k_1, k_2;
+	if (hsl.s < 0.8) {
+		t = 1.25 * hsl.s;
+		k_0 = 0;
+		k_1 = 0.8 * C_0;
+		k_2 = 1 - k_1 / C_mid;
+	} else {
+		t = 5 * (hsl.s - 0.8);
+		k_0 = C_mid;
+		k_1 = (0.2 * C_mid * C_mid * 1.25 * 1.25) / C_0;
+		k_2 = 1 - k_1 / (C_max - C_mid);
+	}
+	let C = k_0 + (t * k_1) / (1 - k_2 * t);
+	ret.a = C * a_;
+	ret.b = C * b_;
+
+	return ret;
+}