MapView overlay is cutting off after zoom in - swift3

Question

I am facing a weird problem with MKMapView. I have used a MKOverlayRenderer. Now the problem is when I am zooming out image showing correctly. But in case of zoom in, some portion of the image are cutting off. It's looking like a portion of MapView is coming above the overlay. Following is my overlay renderer code.
class MapOverlayRenderer: MKOverlayRenderer {
var overlayImage: UIImage
var plan: Plan
init(overlay: MKOverlay, overlayImage: UIImage, plan: Plan) {
self.overlayImage = overlayImage
self.plan = plan
super.init(overlay: overlay)
}
override func draw(_ mapRect: MKMapRect, zoomScale: MKZoomScale, in ctx: CGContext) {
let theMapRect = overlay.boundingMapRect
let theRect = rect(for: theMapRect)
// Rotate around top left corner
ctx.rotate(by: CGFloat(degreesToRadians(plan.bearing)));
// Draw the image
UIGraphicsPushContext(ctx)
overlayImage.draw(in: theRect, blendMode: CGBlendMode.normal, alpha: 1.0)
UIGraphicsPopContext();
}
func degreesToRadians(_ x:Double) -> Double {
return (M_PI * x / 180.0)
}
}
Though I don't know the actual reason but when I am commenting ctx.rotate(by:) function this problem is been fixed. But that's not my solution cause image has to be in position.

Answer 1

Please Try below.
override func draw(_ mapRect: MKMapRect, zoomScale: MKZoomScale, in ctx: CGContext) {
DispatchQueue.main.async {
let theMapRect = overlay.boundingMapRect
let theRect = rect(for: theMapRect)
// Rotate around top left corner
ctx.rotate(by: CGFloat(degreesToRadians(plan.bearing)));
// Draw the image
UIGraphicsPushContext(ctx)
overlayImage.draw(in: theRect, blendMode: CGBlendMode.normal, alpha: 1.0)
UIGraphicsPopContext();
}
}