         }
         checkerImage = UIGraphicsGetImageFromCurrentImageContext()
         UIGraphicsEndImageContext()
-        checkerView.image = checkerImage
-        thumbImage.image = checkerImage
+        
+        let temp = backgroundMode
+        backgroundMode = .limit
+        backgroundMode = temp
     }
 
     override func didReceiveMemoryWarning() {

    
    @IBAction func switchBackground() {
        print("switchBackground")
    }
    
    @IBAction func undo() {

            return CGAffineTransformTranslate(xf, -(size.width - self.image.size.width / sy) / 2.0, 0)
        }
    }()
    
    private func updateUI() {
        print("updateUI", index, layers.count)
