Multiple cutouts

gistfile1.txt

//: A UIKit based Playground for presenting user interface
  
import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    lazy var hello: UILabel = {
        let hello = UILabel()
        hello.frame = CGRect(x: 50, y: 200, width: 50, height: 50)
        hello.text = "Hello"
        hello.textColor = .black
        hello.textAlignment = .center
        return hello
    }()
    
    lazy var world: UILabel = {
        let world = UILabel()
        world.frame = CGRect(x: 150, y: 200, width: 50, height: 50)
        world.text = "World"
        world.textColor = .black
        world.textAlignment = .center
        return world
    }()
    
    lazy var bam: UILabel = {
        let bam = UILabel()
        bam.frame = CGRect(x: 250, y: 200, width: 50, height: 50)
        bam.text = "!"
        bam.textColor = .black
        bam.textAlignment = .center
        return bam
    }()
    
    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white

        view.addSubview(hello)
        view.addSubview(world)
        view.addSubview(bam)
        
        self.view = view
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        let cutoutView = CutoutView()
        cutoutView.frame = view.frame
        cutoutView.cutoutPaths = [
            circularCutoutPath(hello),
            circularCutoutPath(world),
            circularCutoutPath(bam)
        ]
        
        view.addSubview(cutoutView)
    }
    
    func circularCutoutPath(_ view: UIView) -> UIBezierPath {
        let circlePath = UIBezierPath(arcCenter: view.center, radius: view.frame.width/2, startAngle: CGFloat(-rad(90)), endAngle: CGFloat(rad(360-90)), clockwise: true)
        
        return circlePath
    }
}

func rad(_ degrees: Double) -> Double {
    return degrees * .pi / 180.00
}

class CutoutView: UIView {
    
    var fillColor: UIColor = UIColor.black.withAlphaComponent(0.8) {
        didSet {
            setNeedsDisplay()
        }
    }
    var cutoutPaths: [UIBezierPath] = [] {
        didSet {
            setNeedsDisplay()
        }
    }
    
    override func draw(_ rect: CGRect) {
        layer.sublayers?.removeAll()
        
        let maskLayer = CAShapeLayer()
        maskLayer.frame = bounds
        maskLayer.fillColor = fillColor.cgColor
        maskLayer.fillRule = kCAFillRuleEvenOdd
        
        let path = UIBezierPath(rect: bounds)
        
        for cutoutPath in cutoutPaths {
            path.append(cutoutPath)
        }
        maskLayer.path = path.cgPath
        
        layer.mask = maskLayer
    }
}

// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()