swift - 使用 AVFoundation 旋转 UIViewRepresentable View

Question

我使用 CameraPreview (UIViewRepresentable) 作为 UIKit 和 SwiftUI 之间的桥梁。 CameraPreview 使用 CameraModel 配置并使用 AVCaptureVideoPreviewLayer。 CameraModel 正在配置 AVCaptureSession 和 AVCaptureDeviceInput。一切正常，除了当我尝试在 iPad 上旋转设备时除外。 CameraPreview 未正确旋转并使用之前旋转的输入。 (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。在我发现设备旋转后，有什么想法如何在 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:

1. 使预览框架适应边界而不是框架。

2. 当我检测到某些 super View View 上的设备方向发生变化时，我会更改 deviceRotation 变量的值，这会自动触发 updateUIView > 功能。

    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
     }  
   }
   

3. 手动设置 AVCaptureConnection 上的 AVCaptureVideoOrientation 以正确的设备方向。每次当我检测到方向变化时我都会这样做:

   previewConnection.videoPreviewLayer?.connection?.videoOrientation = orientation.videoOrientation