import type { VFXElement } from "./types.js";
export type FreezeHooks = {
    /** Show the element's plain content while it is frozen. */
    showPlain(e: VFXElement): void;
    /** Hide the plain content again, restoring `opacity` for DOM elements. */
    hidePlain(e: VFXElement, opacity: string): void;
    isRegistered(e: VFXElement): boolean;
};
/** Tracks the roots frozen by `freezeInside`, including elements added under them later. */
export declare class FreezeTracker {
    #private;
    constructor(hooks: FreezeHooks);
    /**
     * Freeze the elements inside `root`, and any added under it until the undo.
     * Returns a function that undoes it.
     */
    freezeInside(root: HTMLElement, elements: readonly VFXElement[]): () => void;
    /**
     * Freeze a new element if it sits under a frozen root.
     * `hiddenOpacity` is the opacity it gets once unfrozen; null keeps the current one.
     * Returns whether it was frozen.
     */
    adopt(e: VFXElement, hiddenOpacity: string | null): boolean;
}