thi-ng/umbrella

import type { NumericArray } from "@thi.ng/api";
import type { IRandom } from "@thi.ng/random";
import type { Color, ColorFactory, ReadonlyColor, TypedColor } from "../api.js";
import { defColor } from "../defcolor.js";
import { labLabD65_50 } from "../lab/lab-lab.js";
import { labLch, lchLab } from "../lab/lab-lch.js";
import { labRgb } from "../lab/lab-rgb.js";
import { rgbLab } from "../rgb/rgb-lab.js";
import { xyzLab } from "../xyz/xyz-lab.js";
import { xyzXyzD65_50 } from "../xyz/xyz-xyz.js";

export declare class LCH implements TypedColor<LCH> {
    buf: NumericArray;
    offset: number;
    stride: number;
    l: number;
    c: number;
    h: number;
    alpha: number;
    [id: number]: number;
    readonly mode: "lch";
    readonly length: 4;
    readonly range: [ReadonlyColor, ReadonlyColor];
    readonly xyz: [number, number, number];
    [Symbol.iterator](): Iterator<number, any, undefined>;
    clamp(): this;
    copy(): LCH;
    copyView(): LCH;
    deref(): Color;
    empty(): LCH;
    eqDelta(o: LCH, eps?: number): boolean;
    randomize(rnd?: IRandom): this;
    set(src: ReadonlyColor): this;
    toJSON(): number[];
}

/**
 * Luminance Chroma Hue (conversions assume {@link D50} white point, as per CSS
 * spec). Polar version of {@link labD50}.
 *
 * @remarks
 * Note: As with other hue-based color modes in this package, the hue is stored
 * normalized (in [0..1] interval) and NOT as degrees.
 */
export const lch = <ColorFactory<LCH>>defColor({
    mode: "lch",
    channels: {
        c: { range: [0, 1.312] },
        h: { hue: true },
    },
    order: <const>["l", "c", "h", "alpha"],
    from: {
        rgb: (out, src) => labLch(null, rgbLab(out, src)),
        lab50: labLch,
        lab65: [labLabD65_50, labLch],
        xyz50: [xyzLab, labLch],
        xyz65: [xyzXyzD65_50, xyzLab, labLch],
    },
    toRgb: [lchLab, labRgb],
});