Scaling the contents on UIWindow.

UIWindow+scale.swift

extension UIWindow {
    
    var scale: CGFloat {
        get {
            return sqrt(transform.a * transform.a + transform.c * transform.c)
        }

        set {
            if newValue == 1.0 {
                transform = CGAffineTransform.identity
            } else {
                transform = CGAffineTransform.identity.scaledBy(x: newValue / 1.0, y: newValue / 1.0)
            }
            frame = UIScreen.main.bounds
        }
    }

}