import { UIObject } from "./UIObject";
export interface UIColorDescriptor {
    red: number;
    green: number;
    blue: number;
    alpha?: number;
}
export type UIColorSemanticKey = string;
export declare class UIColor extends UIObject {
    static _liveColors: WeakRef<UIColor>[];
    static _registrationMap: Map<string, UIColor>;
    static _cssSubscriptions: Map<string, Set<() => void>>;
    stringValue: string;
    semanticKey?: UIColorSemanticKey;
    _semanticClass?: typeof UIColor;
    _elementRef?: HTMLElement;
    _styleProperty?: string;
    constructor(stringValue: string, semanticKey?: UIColorSemanticKey);
    toString(): string;
    /**
     * Re-resolves this instance's stringValue from its class's static getter
     * matching the semanticKey, then writes the new value directly to the DOM
     * via the stored element reference and style property.
     * No-op if this instance has no semanticKey.
     */
    apply(): void;
    /**
     * Assigns a semantic key and the class that owns it to this color instance.
     * Intended for derived colors that should participate in theme switching,
     * e.g. `BSColor._primaryBase.colorWithAlpha(0.5).withSemanticKey("primaryShadow", BSColor)`.
     * Returns `this` for fluent chaining.
     */
    withSemanticKey(semanticKey: UIColorSemanticKey, semanticClass: typeof UIColor): this;
    /**
     * Iterates all live registered UIColor instances, calls apply() on each,
     * compacts dead WeakRefs in the same pass, then fires any CSS subscriptions
     * whose semantic key was affected.
     */
    static applySemanticColors(): void;
    /**
     * Updates the backing field for a semantic color and re-applies all live
     * semantic colors. The backing field is always `_` + semanticKey, e.g.
     * `BSColor.updateSemanticColor("primary", "#ff0000")` sets `BSColor._primary`.
     * Called as a static method on the subclass that owns the color.
     */
    static updateSemanticColor(semanticKey: UIColorSemanticKey, value: string): void;
    /**
     * Registers a callback to be fired when applySemanticColors() affects
     * the given semantic key. Intended for injected CSS blocks that cannot
     * be tracked via the colorStyleProxy.
     */
    static subscribe(semanticKey: UIColorSemanticKey, callback: () => void): void;
    static unsubscribe(semanticKey: UIColorSemanticKey, callback: () => void): void;
    static get redColor(): UIColor;
    static get blueColor(): UIColor;
    static get greenColor(): UIColor;
    static get yellowColor(): UIColor;
    static get blackColor(): UIColor;
    static get brownColor(): UIColor;
    static get whiteColor(): UIColor;
    static get greyColor(): UIColor;
    static get lightGreyColor(): UIColor;
    static get transparentColor(): UIColor;
    static get clearColor(): UIColor;
    static get undefinedColor(): UIColor;
    static get nilColor(): UIColor;
    static nameToHex(name: string): string | undefined;
    static hexToDescriptor(c: string): UIColorDescriptor;
    static rgbToDescriptor(colorString: string): {
        red: number;
        green: number;
        blue: number;
        alpha: number;
    };
    get colorDescriptor(): UIColorDescriptor;
    colorWithRed(red: number): UIColor;
    colorWithGreen(green: number): UIColor;
    colorWithBlue(blue: number): UIColor;
    colorWithAlpha(alpha: number): UIColor;
    static colorWithRGBA(red: number, green: number, blue: number, alpha?: number): UIColor;
    static colorWithDescriptor(descriptor: UIColorDescriptor): UIColor;
    private static defaultAlphaToOne;
    colorByMultiplyingRGB(multiplier: number): UIColor;
    /**
     * Returns the perceptual lightness (L*) of this color in the range [0, 1],
     * using the CIELAB formula. 0 = absolute black, 1 = absolute white.
     * Unlike raw relative luminance, this scale is perceptually uniform —
     * 0.5 is the genuine visual midpoint between black and white.
     */
    get perceivedLightness(): number;
    get isLight(): boolean;
}