使用 AVFoundation 旋转 UIViewRepresentable View

Question

我正在使用 CameraPreview (UIViewRepresentable) 作为 UIKit 和 SwiftUI 之间的桥梁。 CameraPreview配置为CameraModel，使用AVCaptureVideoPreviewLayer。 CameraModel 正在配置 AVCaptureSession 和 AVCaptureDeviceInput。一切正常，除非我尝试在 iPad 上旋转设备。 CameraPreview 未正确旋转并使用上一次旋转的输入。（下图）我可以在 SwiftUI (based on this article) 中检查正在旋转的设备，但我不知道如何重新配置 CameraPreview 和 AVCaptureVideoPreviewLayer 的旋转。知道如何在我发现设备旋转后在 UIKit 中触发布局更新吗？

代码如下：

struct CameraView: View {
    @StateObject var camera = CameraModel()

    var body: some View {
            CameraPreview(camera: camera)
                .ignoresSafeArea(.all, edges: .all)
     }
}

struct CameraPreview: UIViewRepresentable {
    @ObservedObject var camera: CameraModel
    
    func makeUIView(context: Context) -> UIView {
        let view = UIView(frame: UIScreen.main.bounds)
        camera.preview = AVCaptureVideoPreviewLayer(session: camera.session)
        camera.preview.frame = view.frame
        
        //your own properies
        camera.preview.videoGravity = .resizeAspectFill
        view.layer.addSublayer(camera.preview)
        
        //starting session
        camera.session.startRunning()
        return view
    }
    
    func updateUIView(_ uiView: UIViewType, context: Context) { }
}

class CameraModel: NSObject, ObservableObject, AVCapturePhotoCaptureDelegate {
    @Published var session = AVCaptureSession()
    @Published var preview: AVCaptureVideoPreviewLayer!
    @Published var output = AVCapturePhotoOutput()

    func setUp() {
        do {
            self.session.beginConfiguration()
            let device = AVCaptureDevice.default(for: .video)
            let input = try AVCaptureDeviceInput(device:device!)
            if self.session.canAddInput(input) {
                self.session.addInput(input)
            } 
            if self.session.canAddOutput(self.output) {
                self.session.addOutput(self.output)
            } 
            self.session.commitConfiguration()
            
        }catch {
            print(error.localizedDescription)
        }
    }
}

Answer 1

我通过以下方式解决了这个问题：

将预览帧调整为 bounds 而不是 frame。

当我在某些超级视图 View 上检测到设备方向发生变化时，我更改了 deviceRotation 变量的值，这会自动触发 updateUIView 函数。

 struct CameraPreview: UIViewRepresentable {
   @ObservedObject var camera: CameraModel
   var deviceRotation: UIDeviceOrientation

  func makeUIView(context: Context) -> UIView {
     let view = UIView(frame: UIScreen.main.bounds)
     camera.preview = AVCaptureVideoPreviewLayer(session: camera.session)
     camera.preview.frame = view.bounds

     //your own properies
     camera.preview.videoGravity = .resizeAspectFill
     view.layer.addSublayer(camera.preview)

     //starting session
     camera.session.startRunning()
     return view
  }

  func updateUIView(_ uiView: UIViewType, context: Context) {
     let view = UIView(frame: UIScreen.main.bounds)
     camera.preview.frame = view.bounds
  }  
}

在 AVCaptureConnection 上手动设置 AVCaptureVideoOrientation 以更正设备方向。每次检测到方向变化时，我都会这样做：
```
previewConnection.videoPreviewLayer?.connection?.videoOrientation = orientation.videoOrientation
```

使用 AVFoundation 旋转 UIViewRepresentable View

Rotation of UIViewRepresentable View using AVFoundation

avfoundation

swift

swiftui

uiviewcontrollerrepresentable