import { Ref } from 'vue';
/**
 * Draws the connecting line of a timeline as a single SVG path. Each item
 * registers its marker element; the line is measured from the markers that are
 * actually rendered and drawn as vertical segments between consecutive markers,
 * leaving a gap around each one. Because the line lives in a single overlay it
 * never has to be masked against the background, so it works on any surface.
 */
export declare function useTimeline(container: Readonly<Ref<HTMLElement | null>>): {
    registerMarker: (element: Readonly<Ref<HTMLElement | null>>) => () => void;
    linePath: Ref<string, string>;
};