/** A sideways strip's two questions as arithmetic, since a unit test has no rendered box. `stripEdges`:
 *  which end hides content, since a flush last item looks like a complete strip. `scrollToShow`: where to
 *  stand so one item is wholly visible, since a record opened at its fourth stage must not show the first. */
/** Edges in any one coordinate system, both boxes read in the same one. */
export interface StripEdge {
    left: number;
    right: number;
}
/** A sub-pixel `scrollWidth` excess is not a hidden item; `scrollLeft` is negative in RTL, so distance is
 *  read as a magnitude. */
export declare function stripEdges(scrollLeft: number, scrollWidth: number, clientWidth: number): {
    behind: boolean;
    ahead: boolean;
};
/** `null` when already in view, so a caller never writes a no-op scroll. Scrolls the shorter way, to the
 *  trailing edge and no further, keeping earlier stages on screen. `pad` leaves some of what is behind
 *  showing, so the strip reads as continuing. */
export declare function scrollToShow(box: StripEdge, item: StripEdge, scrollLeft: number, pad?: number): number | null;