Rec. 2100 HLG

import { Color } from "saturon";
import { MATRICES } from "saturon/converters";

/**
 * @see {@link https://www.w3.org/TR/css-color-hdr-1/|CSS Color HDR Module Level 1}
 */
Color.register("color-spaces", [
    {
        name: "rec2100-hlg",
        value: {
            components: ["r", "g", "b"],
            bridge: "xyz-d65",
            toLinear: (c: number) => {
                const a = 0.17883277;
                const b = 1 - 4 * a;
                const c1 = 0.5 - a * Math.log(4 * a);
                if (c <= 0.5) return c ** 2 / 3;
                return (Math.exp((c - c1) / a) + b) / 12;
            },
            fromLinear: (E: number) => {
                const a = 0.17883277;
                const b = 1 - 4 * a;
                const c1 = 0.5 - a * Math.log(4 * a);
                const sign = E < 0 ? -1 : 1;
                const absE = Math.abs(E);
                if (absE <= 1 / 12) return sign * Math.sqrt(3 * absE);
                return sign * (a * Math.log(12 * absE - b) + c1);
            },
            toBridgeMatrix: MATRICES.REC2020_to_XYZD65,
            fromBridgeMatrix: MATRICES.XYZD65_to_REC2020,
        },
    },
]);

import { Color } from "saturon";

const valid = Color.isValid("color(rec2100-hlg 1 0 0)");
console.log(valid); // true

const color = new Color("rec2100-hlg", [1, 0, 0]);
const inGamut = color.inGamut("rec2100-hlg");
console.log(inGamut); // true