Swift 3.0
Swift 4.1
extension CALayer {
func addBorder(edge: UIRectEdge, color: UIColor, thickness: CGFloat) {
let border = CALayer()
switch edge {
case UIRectEdge.top:
border.frame = CGRect(x: 0, y: 0, width: frame.width, height: thickness)
case UIRectEdge.bottom:
border.frame = CGRect(x:0, y: frame.height - thickness, width: frame.width, height:thickness)
case UIRectEdge.left:
border.frame = CGRect(x:0, y:0, width: thickness, height: frame.height)
case UIRectEdge.right:
border.frame = CGRect(x: frame.width - thickness, y: 0, width: thickness, height: frame.height)
default: do {}
}
border.backgroundColor = color.cgColor
addSublayer(border)
}
}