import { Color } from "../color";
import { HslDetector } from "../detector/hsl-detector";
/**
* HSL表現の抽出処理を提供します。
*/
class HslExtractor {
/**
* 色情報を抽出します。
* @param {String} expression WEBカラーの色表現。
* @return {Color} 抽出結果を返します。
*/
extract(expression) {
const detector = new HslDetector();
if (!detector.match(expression)) return null;
const head = expression.indexOf("(");
const tail = expression.indexOf(")");
const body = expression.slice(head + 1, tail);
const values = body.split(",");
const hue = Number(values[0].trim());
const saturation = Number(values[1].replace(/[^0-9.]/g, ""));
const lightness = Number(values[2].replace(/[^0-9.]/g, ""));
/* ---------------------------------------------------------------------- */
// 30-seconds-of-code (Licensed under CC BY 4.0)
// https://www.30secondsofcode.org/js/s/hsl-to-rgb
const hslToRgb = (h, s, l) => {
s /= 100;
l /= 100;
const k = n => (n + h / 30) % 12;
const a = s * Math.min(l, 1 - l);
const f = n => l - a * Math.max(-1, Math.min(k(n) - 3, Math.min(9 - k(n), 1)));
return [255 * f(0), 255 * f(8), 255 * f(4)];
};
/* ---------------------------------------------------------------------- */
const rgb = hslToRgb(hue, saturation, lightness).map(x => Math.round(x));
return new Color(rgb[0], rgb[1], rgb[2], null);
}
}
export { HslExtractor };
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