         context.addLine(to: CGPoint(x: self.frame.size.width - 30, y: self.frame.size.height))   //终点坐标
         
         context.strokePath();
-    
+        
     }
 }
 

        return .portrait
    }
    

    
    
    override func viewDidLoad() {
        super.viewDidLoad()

        
    
        let devices = AVCaptureDevice.devices().filter{ ($0 as AnyObject).hasMediaType(AVMediaTypeVideo) && ($0 as AnyObject).position == AVCaptureDevicePosition.back }
        captureDevice = devices.first as? AVCaptureDevice
        if (captureDevice?.isFlashModeSupported(.auto))!{

        
    }
    
    func touchFocus(sender: UITapGestureRecognizer) {
        
        let point =   sender.location(in: self.view)
        
