/**
 * panel-resize - the drag math behind a dropdown panel's bottom resize grip
 * (the "····" handle). Rune-free and DOM-only so every popover select can reuse
 * it: on the grip's `pointerdown` it tracks the pointer and reports a clamped
 * height as it moves, releasing its listeners on `pointerup`.
 *
 * The grip is only meaningful when the panel opens DOWNWARD (it grows toward the
 * bottom of the screen); components hide it on an upward flip, where there is no
 * room below to grow into.
 */
export type PanelResizeOptions = {
    /** Panel height (px) at the moment the drag starts. */
    startHeight: number;
    /** Smallest height the panel may shrink to. Default 80. */
    min?: number;
    /** Largest height the panel may grow to - the live viewport ceiling. */
    max: () => number;
    /** Called with the new clamped height on each pointer move. */
    onHeight: (height: number) => void;
};
/**
 * Begin a vertical resize from a grip `pointerdown`. Returns nothing; the drag
 * ends itself on `pointerup`. Safe to call from an `onpointerdown` handler.
 */
export declare function startPanelResize(event: PointerEvent, opts: PanelResizeOptions): void;