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

            return
        }
        
        guard purePoints.count != 0 else {
            return
        }

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