Rotation only in one ViewController

I’d recommend using supportedInterfaceOrientationsForWindow in your appDelegate to allow rotation only in that specific view controller, ex:

Swift 4/Swift 5

func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {

    // Make sure the root controller has been set
    // (won't initially be set when the app is launched)
    if let navigationController = window?.rootViewController as? UINavigationController {

        // If the visible view controller is the
        // view controller you'd like to rotate, allow
        // that window to support all orientations
        if navigationController.visibleViewController is SpecificViewController {
            return UIInterfaceOrientationMask.all
        } 

        // Else only allow the window to support portrait orientation
        else {
            return UIInterfaceOrientationMask.portrait
        }
    }

    // If the root view controller hasn't been set yet, just
    // return anything
    return UIInterfaceOrientationMask.portrait
}

Note that if that SpecificViewController is in landscape before going to a portrait screen, the other view will still open in landscape. To circumvent this, I’d recommend disallowing transitions while that view is in landscape.

---

Swift 3

func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> Int {

    // Make sure the root controller has been set
    // (won't initially be set when the app is launched)
    if let navigationController = self.window?.rootViewController as? UINavigationController {

        // If the visible view controller is the
        // view controller you'd like to rotate, allow
        // that window to support all orientations
        if navigationController.visibleViewController is SpecificViewController  {
            return Int(UIInterfaceOrientationMask.All.rawValue)
        }

        // Else only allow the window to support portrait orientation
        else {
            return Int(UIInterfaceOrientationMask.Portrait.rawValue)
        }
    }

    // If the root view controller hasn't been set yet, just
    // return anything
    return Int(UIInterfaceOrientationMask.Portrait.rawValue)
}