A UIView with rounded corners

RoundedCornersView.swift

//
//  RoundedCornersView.swift
//
//  Created by Jeroen Wesbeek on 24/11/16.
//  Copyright © 2016 Jeroen Wesbeek. All rights reserved.
//
import Foundation
import UIKit

@IBDesignable class RoundedCornersView: UIView {
    public var roundedCorners: UIRectCorner = .allCorners
    @IBInspectable public var cornerRadius: CGFloat = 1.0 {
        didSet {
            if cornerRadius != oldValue {
                setNeedsLayout()
            }
        }
    }
    @IBInspectable public var borderLineWidth: CGFloat = 2.0 {
        didSet {
            if borderLineWidth != oldValue {
                borderLayer.lineWidth = borderLineWidth
                setNeedsLayout()
            }
        }
    }
    @IBInspectable public var borderColor: UIColor = UIColor.gray {
        didSet {
            if borderColor != oldValue {
                borderLayer.strokeColor = borderColor.cgColor
            }
        }
    }
    
    lazy var maskLayer: CAShapeLayer = {
        let maskLayer = CAShapeLayer()
        self.layer.mask = maskLayer
        return maskLayer
    }()
    
    lazy var borderLayer: CAShapeLayer = {
        let borderLayer = CAShapeLayer()
        borderLayer.fillColor = nil
        borderLayer.strokeColor = self.borderColor.cgColor
        borderLayer.lineWidth = self.borderLineWidth
        self.layer.addSublayer(borderLayer)
        return borderLayer
    }()
    
    override func layoutSublayers(of layer: CALayer) {
        super.layoutSublayers(of: layer)
        
        // create bezier path
        let size = CGSize(width: cornerRadius, height: cornerRadius)
        let path = UIBezierPath(roundedRect: bounds, byRoundingCorners: roundedCorners, cornerRadii: size)
        
        // update layers
        maskLayer.path = path.cgPath
        borderLayer.path = path.cgPath
    }
}