设置预览图层的框架会导致框架设置不正确

Question

我在PBJVision上遇到了一些麻烦。

我将它集成到Swift项目中，当我尝试设置预览图层的框架时，会导致框架不一致：

我有这段代码：

var _previewLayer: AVCaptureVideoPreviewLayer = PBJVision.sharedInstance().previewLayer
@IBOutlet weak var previewView: UIView! // this is the white view in the back

let bounds = self.previewView.layer.bounds
_previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
_previewLayer.bounds = bounds
_previewLayer.position = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds))
previewView.layer.addSublayer(_previewLayer)

Answer 1

Have you tried resizing the frame of the _previewLayer when the previewView lays out its subviews?

Subclass UIView for your previewView, set a property for your AVCaptureVideoPreviewLayer, and set its frame to to match your view's bounds:

class PreviewView: UIView {

    let previewLayer: AVCaptureVideoPreviewLayer?

    override func layoutSubviews() {
        self.previewLayer?.frame = self.bounds;
    }
}

Answer 2

我遇到了同样的问题。

我尝试了@rkyr推荐（在viewDidLayoutSubviews方法中设置框架），但没有成功。我还想在不添加子类的情况下修复它。

我能够通过2次更改修复它： - 确保将previewLayer定义为AVCaptureVideoPreviewLayer（CALayer的子类）而不是CALayer，这是我的情况

var previewLayer: AVCaptureVideoPreviewLayer? // :CALayer

• 确保已设置图层的框架，并在设置了图层会话的所有设置后将其添加到视图中：此代码有效：

  captureSession = AVCaptureSession()
  let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)
  do {
      let input = try AVCaptureDeviceInput(device: captureDevice!)
      captureSession?.addInput(input)
  } catch {
      onErrorCloseAndReturn(error: error)
  }
  let dataOutput = AVCaptureVideoDataOutput()
  dataOutput.videoSettings = [((kCVPixelBufferPixelFormatTypeKey as NSString) as String): NSNumber(value: kCVPixelFormatType_32BGRA)]
  dataOutput.alwaysDiscardsLateVideoFrames = true
  if captureSession!.canAddOutput(dataOutput) {
      captureSession?.addOutput(dataOutput)
  }
  captureSession?.commitConfiguration()
  let queue = DispatchQueue(label: "captureQueue")
  dataOutput.setSampleBufferDelegate(self, queue: queue)
  captureSession?.startRunning()
  
  previewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)
  previewLayer?.frame = self.view.layer.bounds
  self.view.layer.addSublayer(previewLayer!)
  

我帮忙...... e