Next major version 2 with PHP 8.1, Symfony 6, Tabler UI, 2FA ... (#2902)

assets/js/widgets/KimaiColor.js

@@ -0,0 +1,38 @@
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/*!
+ * [KIMAI] KimaiColor: handle colors
+ */
+
+export default class KimaiColor {
+
+    /**
+     * @param {string} hexcolor
+     * @return {string}
+     */
+    static calculateContrastColor(hexcolor)
+    {
+        if (hexcolor.slice(0, 1) === '#') {
+            hexcolor = hexcolor.slice(1);
+        }
+
+        if (hexcolor.length === 3) {
+            hexcolor = hexcolor.split('').map(function (hex) { return hex + hex; }).join('');
+        }
+
+        const r = parseInt(hexcolor.substring(0,2),16);
+        const g = parseInt(hexcolor.substring(2,4),16);
+        const b = parseInt(hexcolor.substring(4,6),16);
+
+        // https://gomakethings.com/dynamically-changing-the-text-color-based-on-background-color-contrast-with-vanilla-js/
+        const yiq = ((r * 299) + (g * 587) + (b * 114)) / 1000;
+
+        return (yiq >= 128) ? '#000000' : '#ffffff';
+    }
+
+}