             
             scrollView.center = getChanged()
             panViewAlpha = 1 - getProgress()
-            view.backgroundColor = UIColor(white: 0.0, alpha: panViewAlpha)
+            view.backgroundColor = backgroundColor.withAlphaComponent(panViewAlpha)
             gesture.setTranslation(CGPoint.zero, in: nil)
 
         case .ended:

    
    open var dismissCompletion: (() -> Void)?
    
    open lazy var session: URLSession = {
        let configuration = URLSessionConfiguration.ephemeral
        return URLSession(configuration: configuration, delegate: nil, delegateQueue: OperationQueue.main)

            UIView.animate(withDuration: 0.3,
                animations: {
                    self.scrollView.center = self.panViewOrigin!
                    self.view.backgroundColor = self.backgroundColor
                },
                completion: { _ in
                    self.panViewOrigin = nil
