import { EMPTY_SCROLL_STATE, type ScrollState } from '../model/types';
export type { ScrollState };
export { EMPTY_SCROLL_STATE };
/**
 * Anything that can act as the scrolling viewport for virtualization.
 * `'window'` (or omitting it) uses the page scroll; an element enables
 * virtualization inside an `overflow: auto` panel, modal, or dashboard pane.
 */
export type ScrollTargetOption = Window | HTMLElement | null | undefined | 'window' | (() => Window | HTMLElement | null);
/** Narrow a {@link ScrollTargetOption} to a concrete, live target. */
export declare function resolveScrollTarget(option: ScrollTargetOption): Window | HTMLElement | null;
/**
 * Read current scroll geometry. Performs one `getBoundingClientRect()` on the
 * container, so callers should batch this into an animation frame rather than
 * invoking it per scroll event.
 */
export declare function readScrollState(target: Window | HTMLElement | null, container: HTMLElement | null): ScrollState;
export declare function scrollStatesEqual(a: ScrollState, b: ScrollState): boolean;
/**
 * Observe scroll and resize on `target`, reporting geometry changes.
 *
 * Events are coalesced into at most one report per animation frame, and the
 * container's offset is re-read on every frame — so a sticky header collapsing
 * mid-scroll cannot desynchronise the visible window. Identical consecutive
 * states are suppressed to avoid pointless re-renders.
 *
 * @returns a dispose function that removes every listener.
 */
export declare function createScrollTracker(target: Window | HTMLElement | null, getContainer: () => HTMLElement | null, onChange: (state: ScrollState) => void): () => void;