二维码扫描、更新与创建

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  • 二维码需要用到库AVFoundation

  • 导入库完毕后，按照下面几个步骤来做

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    /// 1.创建输入
        private lazy var inputDevice: AVCaptureDeviceInput? =
        {
           let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
            do{
                let input = try AVCaptureDeviceInput(device: device)
                return input
            }catch
            {
                return nil
            }
        }()
        /// 2.创建输出
        private lazy var output: AVCaptureMetadataOutput = {
           let output = AVCaptureMetadataOutput()
            return output
        }()
        /// 3.创建会话
        private lazy var session: AVCaptureSession = {
            let s = AVCaptureSession()
            s.sessionPreset = "AVCaptureSessionPreset1920x1080"
            return s
        }()
        /// 4.创建预览图层
        private lazy var previewLayer: AVCaptureVideoPreviewLayer = {
           let layer = AVCaptureVideoPreviewLayer(session: self.session)
            layer.frame = UIScreen.mainScreen().bounds
            return layer
        }()

  • 代理捕捉扫描信息

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    extension QRCodeViewController: AVCaptureMetadataOutputObjectsDelegate
    {
        func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!)
        {
            NJLog(metadataObjects.last?.stringValue)
        }
    }

  • 启动扫描

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    private func startScanQRCode()
        {
            // 1.判断是否可以添加输入设备
            if !session.canAddInput(inputDevice)
            {
                return
            }
            // 2.判断是否可以添加输出对象
            if !session.canAddOutput(output)
            {
                return
            }
            // 3.添加输入和输出到会话中
            session.addInput(inputDevice)
            session.addOutput(output)
            // 4.设置输出解析数据类型
            // 必须在输出对象添加到会话之后才可以设置, 否则会报错
            output.metadataObjectTypes = output.availableMetadataObjectTypes
            // 5.设置输出代理, 监听解析到得结果
            output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
            
            // 6.添加预览图层
            view.layer.insertSublayer(previewLayer, atIndex: 0)
    		// 将绘制边框图层添加到预览图层上        previewLayer.addSublayer(drawLayer)
            // 6.利用会话开始扫描
            session.startRunning()
        }

  • 设置感兴趣范围

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    /// 2.创建输出
        private lazy var output: AVCaptureMetadataOutput = {
           let output = AVCaptureMetadataOutput()
            // 设置兴趣点(感兴趣范围), 默认是全屏
            // 注意: 是以横屏的左上角为参照
    //        output.rectOfInterest = CGRect(x: 0, y: 0, width: 0.5, height: 0.5)
            let frame = self.containerView.frame
            let size = self.view.frame.size
            // 由于是按照横屏来计算的, 所以需要将x变为y, y变为x, 将宽变为高, 高变为宽
            output.rectOfInterest = CGRect(x: frame.origin.y / size.height, y: frame.origin.x / size.width, width: frame.size.height / size.height, height: frame.size.width / size.width)
            
            return output
        }()

  • 描绘边框

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    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!)
    {
        // 0. 移除以前的描边
        clearCorners()
        
        for objc in metadataObjects
        {
            // 1.将扫描到二维码的坐标转换为我们能够识别的坐标
           let codeObjc =  previewLayer.transformedMetadataObjectForMetadataObject(objc as! AVMetadataObject)
            // 2.根据转换好的坐标绘制二维码描边
            drawCorners(codeObjc as! AVMetadataMachineReadableCodeObject)
        }
    }
    ///绘制二维码描边
    private func drawCorners(codeObjc: AVMetadataMachineReadableCodeObject)
    {
        if codeObjc.corners == nil || codeObjc.corners.count == 0
        {
            return
        }
        
        // 1.绘制路径
        let subLayer = CAShapeLayer()
        subLayer.lineWidth = 4
        subLayer.strokeColor = UIColor.redColor().CGColor
        subLayer.fillColor = UIColor.clearColor().CGColor
        
        // 2.从传入对象中获取4个点, 创建Path
        let path = UIBezierPath()
        var point = CGPointZero
        var index = 0
        let dictArr = codeObjc.corners
        // 2.1取出第0个点
        // 将字典中的xy转换为CGPoint
        CGPointMakeWithDictionaryRepresentation(dictArr[index++] as! CFDictionaryRef, &point)
        // 2.2移动到第0个点
        path.moveToPoint(point)
        
        // 2.3添加其它的点
        while index < dictArr.count
        {
            CGPointMakeWithDictionaryRepresentation(dictArr[index++] as! CFDictionaryRef, &point)
            path.addLineToPoint(point)
        }
        
        // 2.4关闭路径
        path.closePath()
        
        subLayer.path = path.CGPath
        
        // 3.将layer添加到drawLayer上
        drawLayer.addSublayer(subLayer)
    }
    /// 移除以前的描边
    private func clearCorners()
    {
        if drawLayer.sublayers == nil || drawLayer.sublayers?.count == 0
        {
            return
        }
        
        for subLayer in drawLayer.sublayers!
        {
            subLayer.removeFromSuperlayer()
        }
    }

二维码创建

  • 根据信息创建二维码

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    // 1.生成二维码
           
           // 1.创建滤镜
           let filter = CIFilter(name: "CIQRCodeGenerator")!
           // 2.还原滤镜默认设置
           filter.setDefaults()
           // 3.设置数据
           filter.setValue("极客江南".dataUsingEncoding(NSUTF8StringEncoding), forKey: "inputMessage")
           // 4.从滤镜从取出二维码
           let ciImage = filter.outputImage!
           //        customImageView.image = UIImage(CIImage: ciImage)
           //        customImageView.image = createNonInterpolatedUIImageFormCIImage(ciImage, size: 500)
           let QRCodeImage = createNonInterpolatedUIImageFormCIImage(ciImage, size: 500)
           
           
           // 5.设置图片到界面上
           image.image = QRCodeImage

  • 生成高清放大的图像

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/**
    根据CIImage生成指定大小的高清UIImage
    
    :param: image 指定CIImage
    :param: size    指定大小
    :returns: 生成好的图片
    */
    private func createNonInterpolatedUIImageFormCIImage(image: CIImage, size: CGFloat) -> UIImage {
        
        let extent: CGRect = CGRectIntegral(image.extent)
        let scale: CGFloat = min(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent))
        
        // 1.创建bitmap;
        let width = CGRectGetWidth(extent) * scale
        let height = CGRectGetHeight(extent) * scale
        let cs: CGColorSpaceRef = CGColorSpaceCreateDeviceGray()!
        let bitmapRef = CGBitmapContextCreate(nil, Int(width), Int(height), 8, 0, cs, 0)!
        
        let context = CIContext(options: nil)
        let bitmapImage: CGImageRef = context.createCGImage(image, fromRect: extent)
        
        CGContextSetInterpolationQuality(bitmapRef,  CGInterpolationQuality.None)
        CGContextScaleCTM(bitmapRef, scale, scale);
        CGContextDrawImage(bitmapRef, extent, bitmapImage);
        
        // 2.保存bitmap到图片
        let scaledImage: CGImageRef = CGBitmapContextCreateImage(bitmapRef)!
        
        return UIImage(CGImage: scaledImage)
    }