Present a modal which is less than full screen

Seems like there are a few ways to do this. None are that straight forward.

1. Create a UIViewController and set the background of the top section as clear

2. Use a UIPresentationController

#1 seems like a hack. Smoke and mirrors :)

#2 seems like the proper way to do it. But if your base UIViewController is larger than the expected size, things won't look very nice in the UI.

Here's the code for #2. Here's how my app works:

• SleepViewController is the base VC. When you tap a button on this VC, it will present a modal created from TimePickerViewController

• TimePickerViewController is the modal that will be presented

final class SleepViewController: UIViewController {

   @IBAction func tapStartTimeButton(_ sender: UIButton) {

        let viewController = TimePickerViewController()
        viewController.modalPresentationStyle = .custom // must be .custom to use the presentation controller
        viewController.transitioningDelegate = self // must set the delegate to use the presentation controller
        present(viewController, animated: true, completion: nil)
    }
}

extension SleepViewController: UIViewControllerTransitioningDelegate {

    func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {

        return HalfSizePresentationController(presentedViewController: presented, presenting: presenting)
    }
}

final class HalfSizePresentationController: UIPresentationController {

    override var frameOfPresentedViewInContainerView: CGRect {
         return CGRect(x: 100, y: 300, width: 200, height: 300)
    }
}