Swift - How to create a view with a shape cropped in it

Question

I\'m trying to achieve the result shown in the image using swift 1.2 and xcode 6.

Basically I want to create a view with a shape cut in it to be able to see the the

Answer 1

    //assume you create a UIImageView and content image before execute this code
  let sampleMask = UIView()
    sampleMask.frame = self.view.frame
    sampleMask.backgroundColor =  UIColor.black.withAlphaComponent(0.6)
    //assume you work in UIViewcontroller
    self.view.addSubview(sampleMask)
    let maskLayer = CALayer()
    maskLayer.frame = sampleMask.bounds
    let circleLayer = CAShapeLayer()
    //assume the circle's radius is 150
    circleLayer.frame = CGRect(x:0 , y:0,width: sampleMask.frame.size.width,height: sampleMask.frame.size.height)
    let finalPath = UIBezierPath(roundedRect: CGRect(x:0 , y:0,width: sampleMask.frame.size.width,height: sampleMask.frame.size.height), cornerRadius: 0)
    let circlePath = UIBezierPath(ovalIn: CGRect(x:sampleMask.center.x - 150, y:sampleMask.center.y - 150, width: 300, height: 300))
    finalPath.append(circlePath.reversing())
    circleLayer.path = finalPath.cgPath
    circleLayer.borderColor = UIColor.white.withAlphaComponent(1).cgColor
     circleLayer.borderWidth = 1
    maskLayer.addSublayer(circleLayer)

    sampleMask.layer.mask = maskLayer