相机预览上的 SwiftUI 位置叠加

Question

我正在尝试在使用在某些设备上为纵向，在其他设备上为横向。我可以手动设置坐标但是一直没能得到相机预览框的正确坐标。

这是一个 SwiftUI 应用程序，所以我在一个 UIViewControllerRepresentable。这就是我所拥有的，显然，目标圈子是当设备 and/or 方向改变时总是出错。我似乎无法捕捉存在相机预览的模态视图的框架。我愿意成为能够在模态视图上指定相机预览的框架和位置。

struct CaptureImageView: View {
    @Binding var isShown: Bool
    @Binding var image: Image?
    @Binding var newUIImage: UIImage?
    @Binding var showSaveButton: Bool

    func makeCoordinator() -> Coordinator {
        return Coordinator(isShown: $isShown, image: $newUIImage, showSaveButton: $showSaveButton)
    }
}

extension CaptureImageView: UIViewControllerRepresentable {

    func makeUIViewController(context: UIViewControllerRepresentableContext<CaptureImageView>) -> UIImagePickerController {

        let vc = UIImagePickerController()

        if UIImagePickerController.isSourceTypeAvailable(UIImagePickerController.SourceType.camera) {
            vc.sourceType = .camera
            vc.allowsEditing = true
            vc.delegate = context.coordinator

            let screenSize: CGRect = UIScreen.main.bounds
            let screenWidth = screenSize.width
            let screenHeight = screenSize.height

            vc.cameraOverlayView = CircleView(frame: CGRect(x: (screenWidth / 2) - 50, y: (screenWidth / 2) + 25, width: 100, height: 100))

            return vc
        }
        return UIImagePickerController()
    }

    func updateUIViewController(_ uiViewController: UIImagePickerController, context: UIViewControllerRepresentableContext<CaptureImageView>) {
    }
}

这是想法 - 但目标始终需要居中：

目标文件：

class CircleView: UIView {

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = UIColor.clear
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func draw(_ rect: CGRect) {
        if let context = UIGraphicsGetCurrentContext() {
            context.setLineWidth(3.0)
            UIColor.red.set()

            let center = CGPoint(x: frame.size.width / 2, y: frame.size.height / 2)
            let radius = (frame.size.width - 10) / 2

            context.addArc(center: center, radius: radius, startAngle: 0.0, endAngle: .pi * 2.0, clockwise: true)
            context.strokePath()
        }
    }
}

任何指导将不胜感激。 Xcode版本 11.3.1 (11C504)

Answer 1

虽然我仍然想找到获取相机框架的方法的答案 - 我的目标主要可以通过在 ZStack 中创建一个圆形视图来实现，将相机视图放在 SwiftUI 中的圆形视图后面，例如这个：

if showCaptureImageView {
    ZStack {
        CaptureImageView(isShown: $showCaptureImageView, image: $myImage, newUIImage: $newUIImage, showSaveButton: $showSaveButton)
        
        Circle()
            .stroke(Color.red, style: StrokeStyle(lineWidth: 10 ))
            .frame(width: 100, height: 100)
            .offset(CGSize(width: 0, height: -50.0))
    }
}//if show

Answer 2

如 GrandSteph 所述 - 更好的方法是将相机视图包裹在几何体中 Reader。这是一种方法：

if showCaptureImageView {
    ZStack {
        VStack {
            Rectangle()//just to show that the circle below can be centered
                    .frame(width: 300, height: 150)
                    .background(Color.blue)

            GeometryReader { geo in
                CaptureImageView(isShown: self.$showCaptureImageView, image: self.$image)
                .onAppear {
                    self.cameraWindowWidth = geo.size.width
                    self.cameraWindowHeight = geo.size.height
                }
            }//geo
        }//v

        Circle().frame(width: 50, height: 50)
        .position(x: self.cameraWindowWidth / 2, y: (self.cameraWindowHeight / 2) + 150)
        .foregroundColor(.red)

    }//z
}//if show

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