Interface ZoomContext

interface ZoomContext {
    zoomBy: (delta: number) => void;
    zoomByAt: (delta: number, at: Point) => void;
    zoomByAtWorld: (delta: number, at: Point) => void;
    zoomTo: (targetZoom: number) => void;
    zoomToAt: (targetZoom: number, at: Point) => void;
    zoomToAtWorld: (targetZoom: number, at: Point) => void;
    cleanup(): void;
    setup(): void;
}