/// <reference types="@rbxts/types" />
/// <reference types="@rbxts/types" />
/// <reference types="react" />
/**
 * Returns the current viewport size of the camera.
 * @param listener Optional listener to be called when the viewport changes.
 * @returns A binding to the viewport size.
 */
export declare function useViewport(listener?: (viewport: Vector2) => void): import("@rbxts/react").Binding<Vector2>;