Transparent ViewController to See Parent Below?

Question

I would like to modally add a view controller with a transparent background, so the parent view controller beneath can be seen. (This is in an app for iPhone, not for iPad.)

Answer 1

Answer for Swift 5.

TransparentViewController

self.view.backgroundColor = .clear

PresentingViewController

let viewController = TransparentViewController()
viewController.modalPresentationStyle = .overFullScreen
navigationController.present(viewController, animated: false)