How To Make a Quarter Circle using AutoLayout

Question

How can I make a quadrant (quarter-circle) like the one below, using Auto-Layout in Swift? I understand that UIBezierPath is required but I can't seem to get it to work.

Answer 1

Quick, simple example:

class QuarterCircleView: UIView {
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        // only add the shape layer once
        if layer.sublayers == nil {
            let lay = CAShapeLayer()
            lay.fillColor = UIColor.blue.cgColor
            layer.addSublayer(lay)
        }
        if let lay = layer.sublayers?.first as? CAShapeLayer {
            let center = CGPoint(x: bounds.midX, y: bounds.midY)
            let bez  = UIBezierPath()
            bez.move(to: center)
            bez.addArc(withCenter: center, radius: bounds.width * 0.5, startAngle: .pi, endAngle: .pi * 1.5, clockwise: true)
            bez.close()
            lay.path = bez.cgPath
        }
    }
    
}

Note: you really should show what you've tried when posting a question. Search for CAShapeLayer and read some tutorials.