在多边形内部创建一个洞- Google Maps Swift

import GoogleMaps

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // 创建地图视图
        let camera = GMSCameraPosition.camera(withLatitude: 37.7749, longitude: -122.4194, zoom: 12.0)
        let mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
        self.view = mapView

        // 创建外部多边形
        let outerPolygon = GMSPolygon()
        outerPolygon.path = GMSMutablePath()
        outerPolygon.path?.addLatitude(37.785834, longitude: -122.406417)
        outerPolygon.path?.addLatitude(37.768934, longitude: -122.431297)
        outerPolygon.path?.addLatitude(37.774785, longitude: -122.454979)
        outerPolygon.strokeColor = UIColor.black
        outerPolygon.strokeWidth = 2.0

        // 创建内部多边形
        let innerPolygon = GMSPolygon()
        innerPolygon.path = GMSMutablePath()
        innerPolygon.path?.addLatitude(37.7745, longitude: -122.419)
        innerPolygon.path?.addLatitude(37.7745, longitude: -122.421)
        innerPolygon.path?.addLatitude(37.775, longitude: -122.421)
        innerPolygon.fillColor = UIColor.red

        // 添加多边形到地图
        outerPolygon.map = mapView
        innerPolygon.map = mapView
    }
}