iPhone Plus机型上presentedView显示异常问题排查与解决

在iPhone 7模拟器中，我有一个名为cartView的视图，显示效果如下：

点击cartView底部的next按钮后，会弹出名为presentedView的视图，显示效果正常：

触发弹出的代码 #

let vc = PresentedUserDetailsViewController() 
vc.modalPresentationStyle = .custom 
present(vc, animated: true, completion: nil) 

PresentedUserDetailsViewController核心实现 #

lazy var backdropView: UIView = { 
    let bdView = UIView(frame: self.view.bounds) 
    bdView.backgroundColor = UIColor.black.withAlphaComponent(0.5) 
    return bdView 
}() 

let menuHeight = UIScreen.main.bounds.height / 2

var isPresenting = false 

init() { 
    super.init(nibName: nil, bundle: nil) 
    modalPresentationStyle = .custom 
    transitioningDelegate = self 
} 

自定义转场动画扩展 #

extension PresentedUserDetailsViewController: UIViewControllerTransitioningDelegate, UIViewControllerAnimatedTransitioning { 
    func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? { 
        return self 
    } 
    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? { 
        return self 
    } 
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval { 
        return 1 
    } 
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) { 
        let containerView = transitionContext.containerView 
        let toViewController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to) 
        guard let toVC = toViewController else { return } 
        isPresenting = !isPresenting 
        if isPresenting == true { 
            containerView.addSubview(toVC.view) 
            menuView.frame.origin.y += menuHeight 
            backdropView.alpha = 0 
            UIView.animate(withDuration: 0.4, delay: 0, options: [.curveEaseOut], animations: { 
                self.menuView.frame.origin.y -= self.menuHeight 
                self.backdropView.alpha = 1 
            }, completion: { (finished) in 
                transitionContext.completeTransition(true) 
            }) 
        } else { 
            UIView.animate(withDuration: 0.4, delay: 0, options: [.curveEaseOut], animations: { 
                self.menuView.frame.origin.y += self.menuHeight 
                self.backdropView.alpha = 0 
            }, completion: { (finished) in 
                transitionContext.completeTransition(true) 
            }) 
        } 
    } 
} 

异常情况说明 #

但在iPhone Plus机型（如iPhone 6 Plus、iPhone 7 Plus）中运行时，presentedView显示异常：

此时presentedView无法填满整个屏幕，且背后的cartView（包括next按钮）仍可见。

修改后的预期显示效果（iPhone 6 Plus）：

iPad Air 2上的显示效果：

请问如何让presentedView在iPhone Plus机型上像iPhone 7那样正常显示？

内容的提问来源于stack exchange，提问作者user8653398