ios-深度解析二维码的生成与使用

1  // 1.创建Transform    orginalImage的数据类型为CIImage
2  let scale = imageView.bounds.width / orginalImage.extent.width
3  let transform = CGAffineTransformMakeScale(scale, scale)
4  // 2.放大图片
5  let hdImage = orginalImage.imageByApplyingTransform(transform)

         // 1.创建照片选择控制器
        let ipc = UIImagePickerController()
        // 2.设置来源的类型
        ipc.sourceType = .PhotoLibrary
        // 3.设置代理
        ipc.delegate = self
        // 4.弹出控制器
        presentViewController(ipc, animated: true, completion: nil)
     
          在代理方法中实现    选中图片dismiss掉控制器
    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
          //选中照片
        imageView.image = info[UIImagePickerControllerOriginalImage] as? UIImage
       
        picker.dismissViewControllerAnimated(true, completion: nil)
    }

       // 1.创建识别器
        let detector = CIDetector(ofType: CIDetectorTypeQRCode, context: nil, options: nil)
      
        // 2.获取图片,并且将图片转成CIIImage
        let image = imageView.image!
        guard let ciImage = CIImage(image: image) else {
            return
        } 
        // 3.识别图片中二维码
        let features = detector.featuresInImage(ciImage)
       
        // 4.遍历数组中所有的元素
        for f in features {
          // feature类型是CIFeature  要转换成二维码类型 CIQRCodeFeature
            guard let qrCodeF = f as? CIQRCodeFeature else {
                continue
            }
            //打印二维码的信息
            print(qrCodeF.messageString)
        }

        // 1.改变约束(原来约束为-240)
        scanViewBottomCons.constant = 240  
        // 2.执行动画
        UIView.animateWithDuration(1.0) {
            UIView.setAnimationRepeatCount(MAXFLOAT)
            self.qrCodeView.layoutIfNeeded()
        }

         // 1.创建捕捉会话
        let session = AVCaptureSession()
       
        // 2.设置输入(摄像头)
        let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
        guard let input = try? AVCaptureDeviceInput(device: device) else {
            return
        }
        session.addInput(input)
       
        // 3.设置输出(Metadata)
        let output = AVCaptureMetadataOutput()
        // 设置代理
        output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
        session.addOutput(output)
        // 设置output的输出的类型(该类型的设置必须在添加到session之后)
        output.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
       
        // 4.添加预览图层(可以没有)
        let previewLayer = AVCaptureVideoPreviewLayer(session: session)
        previewLayer.frame = view.bounds
        view.layer.insertSublayer(previewLayer, atIndex: 0)
       
        // 5.开始扫描
        session.startRunning()

func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
  guard let objc = metadataObjects.last as? AVMetadataMachineReadableCodeObject else {
    return
  }
    print(objc.stringValue)
 }

　　　　 // 设置扫描的区域
        let screenW = UIScreen.mainScreen().bounds.width
        let screenH = UIScreen.mainScreen().bounds.height
        let x : CGFloat = qrCodeView.frame.origin.x / screenW
        let y : CGFloat = qrCodeView.frame.origin.y / screenH
        let w : CGFloat = qrCodeView.frame.width / screenW
        let h : CGFloat = qrCodeView.frame.height / screenH
        output.rectOfInterest = CGRect(x: y, y: x, width: h, height: w)