SwiftでViewをaddとremove

                    //remove
                    self.readCanvas?.removeFromSuperview()
                    self.drawCanvas?.removeFromSuperview()
                                        
                    //ReadCanvas
                    self.readCanvas = UIView(frame:self.canvasFrame);
                    self.readCanvas.backgroundColor = UIColor.clearColor()
                    self.baseUiView.addSubview(self.readCanvas);
                    
                    //DrawCanvas
                    self.drawCanvas = UIView(frame:self.canvasFrame);
                    self.drawCanvas.backgroundColor = UIColor.clearColor()
                    self.baseUiView.addSubview(self.drawCanvas);