     }
     
     public func erase() {
-        isUndo = true
+        isErase = true
         lines.removeAll()
         purePoints.removeAll()
         setNeedsDisplay()

    fileprivate let distanceForDraw:CGFloat = 25
    fileprivate var isEnd = false
    fileprivate var isUndo = false
    public      var lineWidth:CGFloat = TLStoryConfiguration.defaultDrawLineWeight
    public      var lineColor:UIColor = UIColor.white
    

            return
        }
        
        if isErase {
            isErase = false
            context?.clear(self.bounds)
        }
        
        guard purePoints.count != 0 else {
            return
        }
