MKPolylineRenderer produces jagged, unequal paths

Question

I am using the iOS 7 MapKit APIs to produce 3D camera movements on a map that displays an MKDirectionsRequest-produced path. The path is rendered by MKOverlayRenderer like s

Answer 1

MKPolyline is not drawing when zoom is changing and when the region is changing. Simple fix below.

public class PolylineRenderer : MKPolylineRenderer {

    private var displayLink: CADisplayLink!
    private var ticks = 0

    override public init(overlay: MKOverlay) {
        super.init(overlay: overlay)

        displayLink = CADisplayLink(target: self, selector:#selector(PolylineRenderer._update))
    displayLink.add(to: .main, forMode: .commonModes)
    }

    func _update() {
        if ticks < 3 {
            ticks+=1
        } else {
            ticks = 0
        }

        if ticks == 0 {
            self.setNeedsDisplay()
        }
    }

    deinit {
        if displayLink != nil {
            displayLink.invalidate()
        }
    }
}

Its pretty simple once you realize its just not painting fast enough. Skipping 3 ticks does not kill the CPU and bye to the jaggies.