import { RefObject } from 'react';
declare type PRect = Partial<DOMRect> & {
    readonly bottom: number;
    readonly height: number;
    readonly left: number;
    readonly right: number;
    readonly top: number;
    readonly width: number;
};
export declare function getTopPosition(targetRect: PRect, popoverRect: PRect): {
    top: string;
};
declare type RefOrId = RefObject<HTMLElement | string | null>;
export declare type PositionCallback = (elem: HTMLElement, anchor: HTMLElement | null) => void;
interface UsePositioning {
    position: PositionCallback;
    visible: boolean;
    ref: RefOrId;
    anchorRef?: RefOrId;
    updateOnScroll?: boolean;
}
export declare function usePositioning({ position, visible, ref, anchorRef, updateOnScroll, }: UsePositioning): void;
export declare const positionDropDown: PositionCallback;
export declare const getViewport: () => Element | null;
export {};