A sizable UIViewController that can be used as a playground liveView and set to specific device sizes.

gistfile1.txt

import UIKit
import PlaygroundSupport

public class DeviceViewController : UIViewController {
    
    public enum ScreenType : Int {
        case iPhone3_5Inch
        case iPhone4Inch // includes 5th & 6h gen iPod Touch
        case iPhone4_7Inch
        case iPhone5_5Inch
        case iPad
        case iPad_12_9Inch
        case tv
    }
    
    override public func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
    }

    static public func setup(screenType: ScreenType, scale: CGFloat = 2.0, isPortrait: Bool = true) -> (UIWindow, DeviceViewController) {
        let vc = DeviceViewController()
        vc.view.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
        let screenSize = DeviceViewController.screenTypeSize(screenType, isPortrait: isPortrait)
        let playgroundSize = CGSize.init(width: screenSize.width*scale, height: screenSize.height*scale)
        let w = UIWindow(frame: CGRect(x: 0, y: 0, width: playgroundSize.width, height: playgroundSize.height))
        w.rootViewController = vc
        w.makeKeyAndVisible()
        return (w, vc)
    }
    
    static private func screenTypeSize(_ screenType:ScreenType, isPortrait:Bool = true) -> CGSize {
        switch screenType {
        case .iPhone3_5Inch:
            return isPortrait ? CGSize(width: 320, height: 480) : CGSize(width: 480, height: 320)
        case .iPhone4Inch:
            return isPortrait ? CGSize(width: 320, height: 568) : CGSize(width: 568, height: 320)
        case .iPhone4_7Inch:
            return isPortrait ? CGSize(width: 375, height: 667) : CGSize(width: 667, height: 375)
        case .iPhone5_5Inch:
            return isPortrait ? CGSize(width: 414, height: 736) : CGSize(width: 736, height: 414)
        case .iPad:
            return isPortrait ? CGSize(width: 768, height: 1024) : CGSize(width: 1024, height: 768)
        case .iPad_12_9Inch:
            return isPortrait ? CGSize(width: 1024, height: 1366) : CGSize(width: 1366, height: 1024)
        case .tv:
            return CGSize(width: 1980, height: 1020)
        }
    }
}

let (window, vc) = DeviceViewController.setup(screenType: .iPhone3_5Inch/*, scale: 2.0, isPortrait: true*/)
PlaygroundPage.current.liveView = window
vc.view.backgroundColor = .orange

Nice! Any plans to update for modern screen sizes?

A more flexible approach found here.