duckengine/src/helper/color/hslToRGB.ts

A 2D Game Engine for the web.

export default function hslToRGB(
	h: number | string,
	s: number | string,
	l: number | string
) {
	let r, g, b;

	h = parseInt(h as string);
	s = parseInt(s as string);
	l = parseInt(l as string);

	if (s === 0) {
		r = g = b = l; // achromatic
	} else {
		const hue2rgb = function hue2rgb(p: number, q: number, t: number) {
			if (t < 0) t += 1;
			if (t > 1) t -= 1;
			if (t < 1 / 6) return p + (q - p) * 6 * t;
			if (t < 1 / 2) return q;
			if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
			return p;
		};

		const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
		const p = 2 * l - q;
		r = hue2rgb(p, q, h + 1 / 3);
		g = hue2rgb(p, q, h);
		b = hue2rgb(p, q, h - 1 / 3);
	}

	return `rgb(${Math.round(r * 255)}, ${Math.round(g * 255)}, ${Math.round(
		b * 255
	)})`;
}