ProgressBar that has circular form with gradient

CircularProgressView.swift

@IBDesignable
public class CircularProgressView: UIView {
    @IBInspectable public var progress: Float = 0 {
        didSet {
            drawProgress()
        }
    }

    public var lineWidth: CGFloat = 4 {
        didSet {
            setNeedsLayout()
        }
    }

    public var startColor: UIColor = .blue {
        didSet {
            setNeedsLayout()
        }
    }

    public var endColor: UIColor = .controlBlue {
        didSet {
            setNeedsLayout()
        }
    }

    var progressBarRadius: CGFloat {
        return (width - 7) / 2
    }

    var backgroundRadius: CGFloat {
        return progressBarRadius - lineWidth
    }

    var tipRadius: CGFloat {
        return progressBarRadius - (lineWidth / 2)
    }

    var hemiCircleCenter: CGPoint {
        return CGPoint(x: frame.width / 2, y: frame.height)
    }

    public override func awakeFromNib() {
        super.awakeFromNib()
        drawProgress()
    }

    public override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        drawProgress()
    }

    public override func layoutSubviews() {
        super.layoutSubviews()
        drawProgress()
    }

    func drawProgress() {
        layer.sublayers = []

        layer.addSublayer(greyStrokeLayer)
        layer.addSublayer(tipLayer)
        layer.addSublayer(gradientLayer)
        layer.addSublayer(backgroundLayer)
        clipsToBounds = true
    }

    var greyStrokeLayer: CAShapeLayer {
        let greyStroke = CAShapeLayer()
        greyStroke.path = UIBezierPath(arcCenter: hemiCircleCenter, radius: backgroundRadius, startAngle: 0, endAngle: CGFloat.pi, clockwise: false).cgPath
        greyStroke.lineWidth = lineWidth * 2
        greyStroke.fillColor = nil
        greyStroke.strokeColor = UIColor.separator.cgColor
        return greyStroke
    }

    var gradientLayer: CAGradientLayer {
        let gradient = CAGradientLayer()
        gradient.frame = CGRect(x: 0, y: 0, width: frame.width * CGFloat(progress), height: frame.height)
        gradient.colors = [startColor, endColor].map { $0.cgColor }
        gradient.startPoint = CGPoint(x: 0.0, y: 0.5)
        gradient.endPoint = CGPoint(x: 1.0, y: 0.5)

        let progressBarLayer = CAShapeLayer()
        progressBarLayer.path = UIBezierPath(arcCenter: hemiCircleCenter, radius: progressBarRadius, startAngle: 0, endAngle: CGFloat.pi, clockwise: false).cgPath
        gradient.mask = progressBarLayer

        return gradient
    }

    var backgroundLayer: CAShapeLayer {
        let backGround = CAShapeLayer()
        backGround.path = UIBezierPath(arcCenter: hemiCircleCenter, radius: backgroundRadius, startAngle: 0, endAngle: CGFloat.pi, clockwise: false).cgPath
        backGround.fillColor = UIColor.secondarySystemGroupedBackground.cgColor
        return backGround
    }

    var tipLayer: CAShapeLayer {
        let tip = CAShapeLayer()
        tip.frame = bounds
        tip.path = UIBezierPath(arcCenter: hemiCircleCenter, radius: tipRadius, startAngle: -CGFloat.pi, endAngle: (CGFloat(progress) - 1) * CGFloat.pi, clockwise: true).cgPath
        tip.strokeColor = endColor.cgColor
        tip.fillColor = nil
        tip.lineCap = .round
        tip.lineWidth = lineWidth
        return tip
    }
}