extensions/notebook-renderers/src/color.ts/HSVA/toRGBA
class HSVA:	static toRGBA(hsva: HSVA): RGBA {
		const { h, s, v, a } = hsva;
		const c = v * s;
		const x = c * (1 - Math.abs((h / 60) % 2 - 1));
		const m = v - c;
		let [r, g, b] = [0, 0, 0];

		if (h < 60) {
			r = c;
			g = x;
		} else if (h < 120) {
			r = x;
			g = c;
		} else if (h < 180) {
			g = c;
			b = x;
		} else if (h < 240) {
			g = x;
			b = c;
		} else if (h < 300) {
			r = x;
			b = c;
		} else if (h <= 360) {
			r = c;
			b = x;
		}

		r = Math.round((r + m) * 255);
		g = Math.round((g + m) * 255);
		b = Math.round((b + m) * 255);

		return new RGBA(r, g, b, a);
	}