Ios 如何使用MetadataOutputRectofFinterestForRect方法和rectOfInterest属性扫描特定区域？（二维码）
我正在建立一个二维码扫描仪与Swift和一切工作在这方面。我遇到的问题是，我试图使整个可视Ios 如何使用MetadataOutputRectofFinterestForRect方法和rectOfInterest属性扫描特定区域？（二维码）,ios,swift,qr-code,avcapturesession,Ios,Swift,Qr Code,Avcapturesession,我正在建立一个二维码扫描仪与Swift和一切工作在这方面。我遇到的问题是，我试图使整个可视AVCaptureVideoPreviewLayer中的一小部分能够扫描二维码。我发现，为了指定屏幕的哪个区域能够读取/捕获二维码，我必须使用名为rectOfInterest的avcaptureMataOutput属性。问题是，当我将其分配给CGRect时，我无法扫描任何内容。在网上做了更多的研究之后，我发现一些建议，我需要使用一种名为metadataOutputRectOfInterestForRect的
AVCaptureVideoPreviewLayerrectOfInterestavcaptureMataOutputmetadataOutputRectOfInterestForRectrectOfInterestmetadataoutputRectOfInterestForRectCGAffineTransformInvert:singular matrixfunc startScan() {
// Get an instance of the AVCaptureDevice class to initialize a device object and provide the video
// as the media type parameter.
let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
// Get an instance of the AVCaptureDeviceInput class using the previous device object.
var error:NSError?
let input: AnyObject! = AVCaptureDeviceInput.deviceInputWithDevice(captureDevice, error: &error)
if (error != nil) {
// If any error occurs, simply log the description of it and don't continue any more.
println("\(error?.localizedDescription)")
return
}
// Initialize the captureSession object.
captureSession = AVCaptureSession()
// Set the input device on the capture session.
captureSession?.addInput(input as! AVCaptureInput)
// Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
let captureMetadataOutput = AVCaptureMetadataOutput()
captureSession?.addOutput(captureMetadataOutput)
// calculate a centered square rectangle with red border
let size = 300
let screenWidth = self.view.frame.size.width
let xPos = (CGFloat(screenWidth) / CGFloat(2)) - (CGFloat(size) / CGFloat(2))
let scanRect = CGRect(x: Int(xPos), y: 150, width: size, height: size)
// create UIView that will server as a red square to indicate where to place QRCode for scanning
scanAreaView = UIView()
scanAreaView?.layer.borderColor = UIColor.redColor().CGColor
scanAreaView?.layer.borderWidth = 4
scanAreaView?.frame = scanRect
view.addSubview(scanAreaView!)
// Set delegate and use the default dispatch queue to execute the call back
captureMetadataOutput.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
captureMetadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
// Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
videoPreviewLayer?.frame = view.layer.bounds
captureMetadataOutput.rectOfInterest = videoPreviewLayer!.metadataOutputRectOfInterestForRect(scanRect)
view.layer.addSublayer(videoPreviewLayer)
// Start video capture.
captureSession?.startRunning()
// Initialize QR Code Frame to highlight the QR code
qrCodeFrameView = UIView()
qrCodeFrameView?.layer.borderColor = UIColor.greenColor().CGColor
qrCodeFrameView?.layer.borderWidth = 2
view.addSubview(qrCodeFrameView!)
view.bringSubviewToFront(qrCodeFrameView!)
// Add a button that will be used to close out of the scan view
videoBtn.setTitle("Close", forState: .Normal)
videoBtn.setTitleColor(UIColor.blackColor(), forState: .Normal)
videoBtn.backgroundColor = UIColor.grayColor()
videoBtn.layer.cornerRadius = 5.0;
videoBtn.frame = CGRectMake(10, 30, 70, 45)
videoBtn.addTarget(self, action: "pressClose:", forControlEvents: .TouchUpInside)
view.addSubview(videoBtn)
view.bringSubviewToFront(scanAreaView!)
}
captureMataOutput.rectOfInterest=videoPreviewLayer！。metadataOutputRectOfInterestForRect（scanRect）scanAreaView！。边界我无法真正澄清metadataOutputRectOfInterestForRect的问题，但是，您也可以直接设置属性。您需要具有视频的宽度和高度分辨率，您可以提前指定。我很快就使用了640*480设置。如文件所述，这些值必须 “相对于设备的自然方向，从左上角的（0,0）延伸到右下角的（1,1）” 看 下面是我试过的代码
var x = scanRect.origin.x/480
var y = scanRect.origin.y/640
var width = scanRect.width/480
var height = scanRect.height/640
var scanRectTransformed = CGRectMake(x, y, width, height)
captureMetadataOutput.rectOfInterest = scanRectTransformed
func avCaptureInputPortFormatDescriptionDidChangeNotification(notification: NSNotification) {
captureMetadataOutput.rectOfInterest = videoPreviewLayer.metadataOutputRectOfInterestForRect(scanRect)
}
var rect = videoPreviewLayer.rectForMetadataOutputRectOfInterest(YourAVMetadataObject.bounds)
dispatch_async(dispatch_get_main_queue(),{
self.qrCodeFrameView.frame = rect
})
我已经尝试过了，矩形始终在指定的区域内。在iOS 9.3.2中，我能够在
AVCaptureSession的startRunning
方法之后立即调用它：
captureSession.startRunning()
let visibleRect = previewLayer.metadataOutputRectOfInterestForRect(previewLayer.bounds)
captureMetadataOutput.rectOfInterest = visibleRect
我写了以下内容：
videoPreviewLayer?.frame = view.layer.bounds
videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
这对我来说很有效，但我仍然不知道为什么。///After
captureSession.startRunning()
///加上这个
if let videoPreviewLayer = self.videoPreviewLayer {
self.captureMetadataOutput.rectOfInterest =
videoPreviewLayer.metadataOutputRectOfInterest(for:
self.getRectOfInterest())
fileprivate func getRectOfInterest() -> CGRect {
let centerX = (self.frame.width / 2) - 100
let centerY = (self.frame.height / 2) - 100
let quadr: CGFloat = 200
let myRect = CGRect(x: centerX, y: centerY, width: quadr, height: quadr)
return myRect
}
Swift 4：
我设法创造了一种拥有感兴趣区域的效果。我尝试了所有建议的解决方案，但该区域要么是CGPoint.zero，要么大小不合适（在将帧转换为0-1坐标后）。对于那些无法让RegionFinterest
工作并且没有优化检测的人来说，这实际上是一种黑客攻击
在：
我有以下代码：
let visualCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
if self.viewfinderView.frame.contains(visualCodeObject.bounds) {
//visual code is inside the viewfinder, you can now handle detection
}
从全摄像机视图中的小矩形（特定区域）读取QRCode/BarCode
<br> **Mandatory to keep the below line after (start running)** <br>
[captureMetadataOutput setRectOfInterest:[_videoPreviewLayer metadataOutputRectOfInterestForRect:scanRect] ];
[_captureSession startRunning];
[captureMetadataOutput setRectOfInterest:[_videoPreviewLayer metadataOutputRectOfInterestForRect:scanRect] ];
**必须在（开始运行）后保留以下行）**
[CaptureMataOutput setRectOfInterest:[u videoPreviewLayer MetadataOutputRectofFinterestForRect:scanRect]；
[_CaptureSessionStartrunning]；
[CaptureMataOutput setRectOfInterest:[u videoPreviewLayer MetadataOutputRectofFinterestForRect:scanRect]；
注:
CaptureMataOutput
-->AVCaptureMataOutput\u videoPreviewLayer
-->AVCaptureVideoPreviewLayerscanRect
-->要读取QRCode的Rect
我知道现在已经有了解决方案，现在已经很晚了，但我通过捕获完整的视图图像，然后使用特定的矩形裁剪来实现我的解决方案
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
if let imageData = photo.fileDataRepresentation() {
print(imageData)
capturedImage = UIImage(data: imageData)
var crop = cropToPreviewLayer(originalImage: capturedImage!)
let sb = UIStoryboard(name: "Main", bundle: nil)
let s = sb.instantiateViewController(withIdentifier: "KeyFobScanned") as! KeyFobScanned
s.image = crop
self.navigationController?.pushViewController(s, animated: true)
}
}
private func cropToPreviewLayer(originalImage: UIImage) -> UIImage? {
guard let cgImage = originalImage.cgImage else { return nil }
let scanRect = CGRect(x: stackView.frame.origin.x, y: stackView.frame.origin.y, width: innerView.frame.size.width, height: innerView.frame.size.height)
let outputRect = videoPreviewLayer.metadataOutputRectConverted(fromLayerRect: scanRect)
let width = CGFloat(cgImage.width)
let height = CGFloat(cgImage.height)
let cropRect = CGRect(x: outputRect.origin.x * width, y: outputRect.origin.y * height, width: outputRect.size.width * width, height: outputRect.size.height * height)
if let croppedCGImage = cgImage.cropping(to: cropRect) {
return UIImage(cgImage: croppedCGImage, scale: 1.0, orientation: originalImage.imageOrientation)
}
return nil
}
可能不相关，但对我来说问题是屏幕方向。在我的肖像只有应用程序，我想有一个条形码扫描仪，只是检测代码在一个水平线在屏幕中部。我认为这会奏效：
CGRect(x: 0, y: 0.4, width: 1, height: 0.2)
相反，我必须用y来切换x，用高度来切换宽度
CGRect(x: 0.4, y: 0, width: 0.2, height: 1)
谢谢你的信息！我尝试使用您提供的代码，但不幸的是，它对我不起作用。我将640*480的值更新为1024*768，因为我使用的是iPad而不是手机，但扫描区域不在我用作目标区域的指定扫描区域内。我在我的应用程序中添加了UIView的图像，以更好地显示我正在努力实现的目标。请参阅更新的帖子，我已经用metadataOutputRectOfInterestForRect解决了这个问题，现在它似乎可以工作了。非常感谢！我以前根本没有扫描过。修正了我的问题：）对我来说还不清楚。我使用的是完全相同的代码
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
if let imageData = photo.fileDataRepresentation() {
print(imageData)
capturedImage = UIImage(data: imageData)
var crop = cropToPreviewLayer(originalImage: capturedImage!)
let sb = UIStoryboard(name: "Main", bundle: nil)
let s = sb.instantiateViewController(withIdentifier: "KeyFobScanned") as! KeyFobScanned
s.image = crop
self.navigationController?.pushViewController(s, animated: true)
}
}
private func cropToPreviewLayer(originalImage: UIImage) -> UIImage? {
guard let cgImage = originalImage.cgImage else { return nil }
let scanRect = CGRect(x: stackView.frame.origin.x, y: stackView.frame.origin.y, width: innerView.frame.size.width, height: innerView.frame.size.height)
let outputRect = videoPreviewLayer.metadataOutputRectConverted(fromLayerRect: scanRect)
let width = CGFloat(cgImage.width)
let height = CGFloat(cgImage.height)
let cropRect = CGRect(x: outputRect.origin.x * width, y: outputRect.origin.y * height, width: outputRect.size.width * width, height: outputRect.size.height * height)
if let croppedCGImage = cgImage.cropping(to: cropRect) {
return UIImage(cgImage: croppedCGImage, scale: 1.0, orientation: originalImage.imageOrientation)
}
return nil
}
CGRect(x: 0, y: 0.4, width: 1, height: 0.2)
CGRect(x: 0.4, y: 0, width: 0.2, height: 1)