如何绘制用户可以在地图上选择特定区域时可以绘制的自定义多边形

Question

我正在制作一个应用程序，该应用程序将通过用户交互来显示地图以选择特定的属性区域，这是通过在Google地图上绘制多边形来实现的，但问题是我想绘制没有线数限制的动态多边形，我的代码只画5条线。我不想限制行数，并且当多边形的起点和终点相遇时，该区域将完全封闭。

我已经尝试过这个Swift Google Maps does not delete polygons

这是我用来实现5行多边形的代码，我正在寻找更好的代码示例

import UIKit
import GoogleMaps

class ViewController: UIViewController {
    var counterMarker: Int = 0
    var allMarkers:[GMSMarker] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    override func loadView() {
        let camera = GMSCameraPosition.camera(withLatitude: -33.86, longitude: 151.20, zoom: 6.0)
        let mapView = GMSMapView.map(withFrame: CGRect.zero, camera: camera)

        mapView.delegate = self
        mapView.isMyLocationEnabled = true
        view = mapView
    }
}

extension ViewController: GMSMapViewDelegate {

    func mapView(_ mapView: GMSMapView, didLongPressAt coordinate: CLLocationCoordinate2D) {
        // Custom logic here
        if counterMarker < 4 {
            let marker = GMSMarker()
            marker.position = coordinate
            marker.title = "I added this with a long tap"
            marker.snippet = ""
            allMarkers.append(marker)
            counterMarker += 1
            // Create the polygon, and assign it to the map.
            mapView.clear()
            let rect = reorderMarkersClockwise(mapView)
            for mark in allMarkers {
                mark.map = mapView
            }
            let polygon = GMSPolygon(path: rect)
            polygon.fillColor = UIColor(red: 0.25, green: 0, blue: 0, alpha: 0.05);
            polygon.strokeColor = .black
            polygon.strokeWidth = 2
            polygon.map = mapView

        }
    }

    func mapView(_ mapView: GMSMapView, didLongPressInfoWindowOf marker: GMSMarker) {
        marker.map = nil
        for (index, cmark) in allMarkers.enumerated() {
            if cmark.position.latitude == marker.position.latitude, cmark.position.longitude == marker.position.longitude {
                allMarkers.remove(at: index)
                break;
            }
        }
        counterMarker -= 1

        mapView.clear()
        let rect = reorderMarkersClockwise(mapView)
        for mark in allMarkers {
            mark.map = mapView
        }

        // Create the polygon, and assign it to the map.
        let polygon = GMSPolygon(path: rect)
        polygon.fillColor = UIColor(red: 0.25, green: 0, blue: 0, alpha: 0.05);
        polygon.strokeColor = .black
        polygon.strokeWidth = 2
        polygon.map = mapView
    }

    func reorderMarkersClockwise(_ mapView: GMSMapView) -> GMSMutablePath {
        let rect = GMSMutablePath()
        if (counterMarker > 1) {
            let arr = allMarkers.map{$0.position}.sorted(by: isLess)
            for pos in arr {
                rect.add(pos)
            }
        } else {
            for mark in allMarkers {
                rect.add(mark.position)
            }
        }
        return rect
    }

    func isLess(_ a: CLLocationCoordinate2D, _ b: CLLocationCoordinate2D) -> Bool {
        let center = getCenterPointOfPoints()

        if (a.latitude >= 0 && b.latitude < 0) {
            return true
        } else if (a.latitude == 0 && b.latitude == 0) {
            return a.longitude > b.longitude
        }

        let det = (a.latitude - center.latitude) * (b.longitude - center.longitude) - (b.latitude - center.latitude) * (a.longitude - center.longitude)
        if (det < 0) {
            return true
        } else if (det > 0) {
            return false
        }

        let d1 = (a.latitude - center.latitude) * (a.latitude - center.latitude) + (a.longitude - center.longitude) * (a.longitude - center.longitude)
        let d2 = (b.latitude - center.latitude) * (b.latitude - center.latitude) + (b.longitude - center.longitude) * (b.longitude - center.longitude)
        return d1 > d2
    }

    func getCenterPointOfPoints() -> CLLocationCoordinate2D {
        let arr = allMarkers.map {$0.position}
        let s1: Double = arr.map{$0.latitude}.reduce(0, +)
        let s2: Double = arr.map{$0.longitude}.reduce(0, +)
        let c_lat = arr.count > 0 ? s1 / Double(arr.count) : 0.0
        let c_lng = arr.count > 0 ? s2 / Double(arr.count) : 0.0
        return CLLocationCoordinate2D.init(latitude: c_lat, longitude: c_lng)
    }
}

我想绘制没有线数限制的动态多边形，我的代码仅绘制5条线。我不想限制行数，并且当多边形的起点和终点相遇时，该区域将完全封闭。