Swift 4 Modal with transparent background

ModalTransparentBackground.swift

//
//  Created by Eduardo Domene Junior on 19/04/2018.
//  Make sure that your view controller in Attributes Inspector is marked as:
// * Presentation - Over the current context
// * Defines context
// * Provides context

import UIKit

class ModalTransparentBackground: UIViewController {
    var backgroundView = UIView()
    
    override func viewDidLoad() {
        view.backgroundColor = UIColor.clear
        view.isOpaque = false
        backgroundView.frame = view.bounds
        backgroundView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
        
        // Get ViewController presenting this modal
        if let parent = self.presentingViewController {
            backgroundView.frame = parent.view.bounds
            backgroundView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
            parent.view.addSubview(backgroundView)
        }
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        backgroundView.removeFromSuperview()
    }
  
    @IBAction func okButtonTapped(_ sender: Any) {
        self.dismiss(animated: true, completion: nil)
    }
    
    deinit {
        print("ModalTransparentBackground deinit")
    }
}