class ViewController: UIViewController {

    @IBOutlet weak var chartView: UIView!

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        createCircularPath()
    }

    fileprivate func createCircularPath() {

        let trakLayer = CAShapeLayer()
        let progress = CAShapeLayer()

        let frame = chartView.frame
        chartView.layer.cornerRadius = chartView.frame.height * 0.5
        chartView.backgroundColor = .clear

        let center = CGPoint(x: frame.width * 0.5, y: frame.height * 0.5)
        let radius = (frame.width - 1.5) / 2
        let startAngle = -0.5 * Double.pi
        let endAngle = 1.5 * Double.pi
        let bezie = UIBezierPath(arcCenter: center, radius: radius, startAngle: CGFloat(startAngle), endAngle: CGFloat(endAngle), clockwise: true)

        trakLayer.path = bezie.cgPath
        trakLayer.fillColor = UIColor.clear.cgColor
        trakLayer.strokeColor = UIColor.red.withAlphaComponent(0.3).cgColor
        trakLayer.lineWidth = 10
        trakLayer.strokeEnd = 1.0

        progress.path = bezie.cgPath
        progress.fillColor = UIColor.clear.cgColor
        progress.strokeColor = UIColor.red.cgColor
        progress.lineWidth = 10
        progress.strokeEnd = 0.50


        chartView.layer.addSublayer(trakLayer)
        chartView.layer.addSublayer(progress)
    }


}