A convenient way is just subclass a UIView
, add a layer on it and make the view color transparent if it's not by default.
import UIKit
class SemiCirleView: UIView {
var semiCirleLayer: CAShapeLayer!
override func layoutSubviews() {
super.layoutSubviews()
if semiCirleLayer == nil {
let arcCenter = CGPoint(x: bounds.size.width / 2, y: bounds.size.height / 2)
let circleRadius = bounds.size.width / 2
let circlePath = UIBezierPath(arcCenter: arcCenter, radius: circleRadius, startAngle: CGFloat.pi, endAngle: CGFloat.pi * 2, clockwise: true)
semiCirleLayer = CAShapeLayer()
semiCirleLayer.path = circlePath.cgPath
semiCirleLayer.fillColor = UIColor.red.cgColor
layer.addSublayer(semiCirleLayer)
// Make the view color transparent
backgroundColor = UIColor.clear
}
}
}