I am trying to draw a semi-circle button. I'm having trouble both drawing the semi-circle and attaching it to the button I made in xcode. The button in xcode has constraints pinning it to the bottom of the screen and centering it. I reference the button in my view controller and then try to override it to a semi-circle as follows. I am getting a blank button. I also hard coded in the coordinates from the storyboard of where the button is. Is there a better way to do that?
let circlePath = UIBezierPath.init(arcCenter: CGPoint(x: 113.0, y: 434.0),
radius: 10.0, startAngle: 0.0, endAngle: CGFloat(M_PI), clockwise: true)
let circleShape = CAShapeLayer()
circleShape.path = circlePath.CGPath
sunButton.layer.mask = circleShape
The problem is that your shape layer is positioned way outside the buttons bounds. If you just add the shape layer as a subview of your button's layer you'll see the problem:
button.layer.addSublayer(circleShape)
You have to adjust the arc center point, so that the arc lies within the button's bounds:
let circlePath = UIBezierPath.init(arcCenter: CGPointMake(button.bounds.size.width / 2, 0), radius: button.bounds.size.height, startAngle: 0.0, endAngle: CGFloat(M_PI), clockwise: true)
let circleShape = CAShapeLayer()
circleShape.path = circlePath.CGPath
button.layer.mask = circleShape
And you'll get this:
Swift 5 update:
let circlePath = UIBezierPath.init(arcCenter: CGPoint(x: button.bounds.size.width / 2, y: 0), radius: button.bounds.size.height, startAngle: 0.0, endAngle: .pi, clockwise: true)
let circleShape = CAShapeLayer()
circleShape.path = circlePath.cgPath
button.layer.mask = circleShape
Swift 5:
// semiCircleDown
let circlePath = UIBezierPath(arcCenter: CGPoint(x: shapeView.bounds.size.width/2, y: 0), radius: shapeView.bounds.size.height, startAngle: 0, endAngle: .pi, clockwise: true).cgPath
//semiCircleUp
let circlePath = UIBezierPath(arcCenter: CGPoint(x: shapeView.bounds.size.width/2, y: 0), radius: shapeView.bounds.size.height, startAngle: 2 * .pi, endAngle: .pi, clockwise: true).cgPath
//quarterCircleRightDown
let circlePath = UIBezierPath(arcCenter: CGPoint(x: 0, y: 0), radius: shapeView.bounds.size.width, startAngle: 2 * .pi, endAngle: .pi * 3/2, clockwise: true).cgPath
//quarterCircleLeftDown
let circlePath = UIBezierPath(arcCenter: CGPoint(x: shapeView.bounds.size.width, y: 0), radius: shapeView.bounds.size.width, startAngle: .pi * 3/2, endAngle: .pi, clockwise: true).cgPath
quarterCircleRightUp
let circlePath = UIBezierPath(arcCenter: CGPoint(x: 0, y: shapeView.bounds.size.height), radius: shapeView.bounds.size.width, startAngle: 0, endAngle: .pi/2, clockwise: false).cgPath
//quarterCircleLeftUp
let circlePath = UIBezierPath(arcCenter: CGPoint(x: shapeView.bounds.size.width, y: shapeView.bounds.size.height), radius: shapeView.bounds.size.width, startAngle: .pi/2, endAngle: .pi, clockwise: false).cgPath
let shape = CAShapeLayer()
shape.path = circlePath.cgPath
shapeView.layer.mask = shape
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