Round button with intrinsic content size

RoundButton.swift

//
//  RoundButton.swift
//
//  Created by Bruno Scheltzke on 04/06/20.
//  Copyright © 2020 Bruno Scheltzke All rights reserved.
//

import UIKit

@IBDesignable
class RoundButton: UIButton {
    
    override var bounds: CGRect {
        didSet {
            setup()
        }
    }
    
    @IBInspectable var cornerRadius: CGFloat {
        set {
            layer.cornerRadius = newValue
            clipsToBounds = newValue > 0
        }
        get {
            return layer.cornerRadius
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setup()
    }
    
    func setup() {
        cornerRadius = frame.height/2.2
        tintColor = .white
        backgroundColor = .systemBlue
        titleLabel?.font = .systemFont(ofSize: 19)
        layer.shadowColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.25).cgColor
        layer.shadowOffset = CGSize(width: 0.0, height: 2.0)
        layer.shadowOpacity = 1.0
        layer.shadowRadius = 0.0
        layer.masksToBounds = false
    }
    
    override var intrinsicContentSize: CGSize {
        let height: CGFloat = 50
        var width: CGFloat = 100
        if let font = self.titleLabel?.font,
            let calculatedWidth = titleLabel?.text?.width(withConstrainedHeight: height, font: font),
            calculatedWidth != 0 {
            width = calculatedWidth + 120
        }
        return CGSize(width: width, height: height)
    }
    
}

@IBDesignable
class PrimaryRoundButton: RoundButton {
    
    override func setup() {
        super.setup()
        backgroundColor = .orange
    }
    
}

extension String {
    
    func width(withConstrainedHeight height: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: .greatestFiniteMagnitude, height: height)
        let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: font], context: nil)

        return ceil(boundingBox.width)
    }
    
}