Subclassing MKAnnotationView and overriding drawRect

extension MapViewController: MKMapViewDelegate {
    func mapView(mapView: MKMapView!, viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView! {
        if let annotation = annotation as? Food {
            if annotation == mapView.userLocation {
                return nil
            }
            let identifier = "pin"
            var view: CustomPin
            if let dequeuedView = mapView.dequeueReusableAnnotationViewWithIdentifier(identifier) as? CustomPin
            {
                dequeuedView.annotation = annotation
                view = dequeuedView
            } else {
                view = CustomPin(annotation: annotation, reuseIdentifier: identifier)
                view.image = annotation.image
            }
            return view
        }
        return nil
    }
}


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import UIKit
import MapKit

class CustomPin: MKAnnotationView {
    override init(annotation:MKAnnotation, reuseIdentifier:String) {
        super.init(annotation: annotation, reuseIdentifier: reuseIdentifier)
        self.canShowCallout = true
        self.opaque = false
    }
    
    override init(frame: CGRect) {
        super.init(frame:frame)
    }
    
    
    required init(coder: NSCoder) {
        fatalError("NSCoding not supported")
    }
    
    override func drawRect(rect: CGRect)
    {
    
        println("Please please please work")
        
        var startAngle: Float = Float(2 * M_PI)
        var endAngle: Float = 0.0

        let strokeWidth = 1.0
        let radius = CGFloat((CGFloat(self.frame.size.width) - CGFloat(strokeWidth)) / 2)

        var context = UIGraphicsGetCurrentContext()

        let center = CGPointMake(self.frame.size.width / 2, self.frame.size.height / 2)

        CGContextSetStrokeColorWithColor(context, UIColor.whiteColor().CGColor)

        CGContextSetLineWidth(context, CGFloat(strokeWidth))
        
        CGContextSetFillColorWithColor(context, UIColor.clearColor().CGColor)

        startAngle = startAngle - Float(M_PI_2)
        endAngle = endAngle - Float(M_PI_2)
        
        CGContextAddArc(context, center.x, center.y, CGFloat(radius), CGFloat(startAngle), CGFloat(endAngle), 0)

        CGContextDrawPath(context, kCGPathStroke)
        
    }
}