Fill an area in the map with a colour - swift

Question

I've been doing a project in Swift 3.
I choose my points by touching in the map and after that I link them with a line.
I've been trying to fill the area between those points with the color Red but without any success. How can I acomplish this?
I set the fill color, in the mapview, but it isn't working.
I have this code so far:
import UIKit
import MapKit
class ViewController: UIViewController, MKMapViewDelegate {
#IBOutlet var map: MKMapView!
var points: [CLLocationCoordinate2D] = [CLLocationCoordinate2D]() //all touched points
override func viewDidLoad() {
super.viewDidLoad()
map.delegate = self
let latitude: CLLocationDegrees = 38.925560
let longitude: CLLocationDegrees = -9.229723
let lanDelta: CLLocationDegrees = 0.05
let lonDelta: CLLocationDegrees = 0.05
let span = MKCoordinateSpan(latitudeDelta: lanDelta, longitudeDelta: lonDelta)
let coordinates = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
let region = MKCoordinateRegion(center: coordinates, span: span)
map.setRegion(region, animated: true)
let uilpgr = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.longpress(gestureRecognizer:)))
uilpgr.minimumPressDuration = 0.5
map.addGestureRecognizer(uilpgr)
}
func longpress(gestureRecognizer: UIGestureRecognizer) {
guard gestureRecognizer.state == .began else { return }
let touchPoint = gestureRecognizer.location(in: self.map)
let coordinate = map.convert(touchPoint, toCoordinateFrom: self.map)
let annotation = MKPointAnnotation()
annotation.coordinate = coordinate
annotation.title = "My Place"
map.addAnnotation(annotation)
// print("longpress activated")
points.append(annotation.coordinate)
let polyline = MKPolyline(coordinates: points, count: points.count)
map.add(polyline)
}
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
let polylineRenderer = MKPolylineRenderer(overlay: overlay)
polylineRenderer.strokeColor = UIColor.blue
polylineRenderer.fillColor = UIColor.red
polylineRenderer.lineWidth = 5
return polylineRenderer
}
}

Answer 1

MKPolyLine will render a line. If you want a filled polygon you need MKPolyon. If you want both an outline and a fill, use both.
fileprivate var polygon: MKPolygon? = nil
func addPolygon() {
let polygon = MKPolygon(coordinates: &polygonCoordinates, count: polygonCoordinates.count)
self.polygon = polygon
mapView.add(polygon)
}
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
if let _ = overlay as? MKPolyline {
let renderer = MKPolylineRenderer(polyline: polyLine!)
renderer.strokeColor = UIColor.blue
renderer.lineWidth = 2
return renderer
} else {
let renderer = MKPolygonRenderer(polygon: polygon)
renderer.fillColor = UIColor.blue.withAlphaComponent(0.25)
return renderer
}
}