Inverted circle overlay on map view (MapKit, MKOverlay, Swift)

Question

I am trying to add a custom overlay onto my map view to create an inverted circle (rather than the typical MKCircle overlay around a pin on the map). I've tried following this thread: Add inverted circle overlay to map view

I have not created a custom MKOverlay subclass, but I have created a custom MKOverlayRenderer subclass that I'm trying to use with MKCircle as the MKOverlay.

class MKInvertedCircleRenderer: MKOverlayRenderer {
var fillColor: UIColor = UIColor.blue

override func draw(_ mapRect: MKMapRect, zoomScale: MKZoomScale, in context: CGContext) {
    let path = UIBezierPath(rect: CGRect(x: mapRect.origin.x, y: mapRect.origin.y, width: mapRect.size.width, height: mapRect.size.height))

    context.setFillColor(fillColor.cgColor)
    context.addPath(path.cgPath)
    context.fillPath()
}}

And this is my mapView delegate call in my view controller:

func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
    switch(overlaySegmentedControl.selectedSegmentIndex) {
    case 0: // Draw circle on map view for region specified for "When I Arrive".
        let circleRenderer = MKCircleRenderer(overlay: overlay)
        circleRenderer.strokeColor = self.view.tintColor
        circleRenderer.lineWidth = 3.0
        circleRenderer.fillColor = self.view.tintColor.withAlphaComponent(0.15)

        return circleRenderer

    case 1: // Draw rectangle with circle cutout on map view for region specified for "When I Leave".
        let circleRenderer = MKInvertedCircleRenderer(overlay: overlay)

        return circleRenderer

    default:
        fatalError("Unspecified segmented control selected: \(overlaySegmentedControl.selectedSegmentIndex)")
    }
}

Currently, case 0 works as expected, by outputting a circle overlay around a pin on the map view.

Case 1 does not work, I was expecting it to draw a rect on the map, filled with my fillColor set in the MKOverlayRenderer subclass - however nothing shows up. I am trying to troubleshoot this before adding the path to cut out a circle in the middle.

Any help would be appreciated!

hubear hubear · Accepted Answer · 2018-02-07T01:18:42

Turns out you can't use MKCircle with a custom MKOverlayRenderer subclass.

You have to create your own custom MKOverlay subclass to work with the custom MKOverlayRenderer subclass.

Inverted circle overlay on map view (MapKit, MKOverlay, Swift)

1 Answers