iOS custom UIButton with roundedRect, shadow and highlight.

MyUIButton.swift

import UIKit

class MyUIButton: UIButton {

    var highlightTitle = false
    var highlightBackground = false
    var highlightLayer = false

    override open var isHighlighted: Bool {
        didSet {
            guard let attributedString = attributedTitle(for: .normal) else {
                return
            }
            var attributes = attributedString.attributes(at: 0, effectiveRange: nil)
            let color = attributes[.foregroundColor] as? UIColor

            if isHighlighted {
                if highlightTitle {
                    attributes[.foregroundColor] = color?.withAlphaComponent(0.5)
                }
                if highlightBackground {
                    backgroundColor = backgroundColor?.withAlphaComponent(0.5)
                }
                if highlightLayer,
                    let shapeLayer = layer.sublayers?[0] as? CAShapeLayer,
                    let cgColor = shapeLayer.fillColor {
                    let colorWithAlpha = UIColor(cgColor: cgColor).withAlphaComponent(0.5)
                    shapeLayer.fillColor = colorWithAlpha.cgColor
                }
            } else {
                if highlightTitle {
                    attributes[.foregroundColor] = color?.withAlphaComponent(1)
                }
                if highlightBackground {
                    backgroundColor = backgroundColor?.withAlphaComponent(1)
                }
                if highlightLayer,
                    let shapeLayer = layer.sublayers?[0] as? CAShapeLayer,
                    let cgColor = shapeLayer.fillColor {
                    let colorWithAlpha = UIColor(cgColor: cgColor).withAlphaComponent(1)
                    shapeLayer.fillColor = colorWithAlpha.cgColor
                }
            }

            let newAttributedString = NSAttributedString(string: attributedString.string,
                                                         attributes: attributes)
            setAttributedTitle(newAttributedString, for: .normal)
        }
    }

    convenience init(highlightTitle: Bool) {
        self.init(frame: .zero)
        self.highlightTitle = highlightTitle
    }
    
    convenience init(highlightBackground: Bool) {
        self.init(frame: .zero)
        self.highlightBackground = highlightBackground
    }
    
    convenience init(highlightLayer: Bool) {
        self.init(frame: .zero)
        self.highlightLayer = highlightLayer
    }

}

// Highlight atributed title
let button1 = MyButton(highlightTitle: true)

// Highlight view.background
let button2 = MyButton(highlightBackground: true)

// Highlight FIRST layer with roundedRect and shadow
let button3 = MyButton(highlightLayer: true)
let shadowLayer = CAShapeLayer()
shadowLayer.path = UIBezierPath(roundedRect: roundedRect, cornerRadius: cornerRadius).cgPath
shadowLayer.fillColor = UIColor(red: 216, green: 66, blue: 152, alpha: 1).cgColor
shadowLayer.shadowPath = shadowLayer.path
shadowLayer.shadowColor = UIColor(red: 216, green: 66, blue: 152, alpha: 1).cgColor
shadowLayer.shadowOffset = CGSize(width: 0, height: 5)
shadowLayer.shadowOpacity = 0.5
shadowLayer.shadowRadius = 10
button3.layer.insertSublayer(shadowLayer, at: 0) // <---- IMPORTANT at 0 position