Basic Camera Display / Buffer Analysis in SwiftUI

cameraView.swift

import SwiftUI
import AVFoundation


struct CameraView: View {
    // Set up the AVCaptureSession and AVCaptureVideoPreviewLayer
    let captureSession = AVCaptureSession()
    let previewLayer = AVCaptureVideoPreviewLayer()
    let cameraDelegate = CameraDelegate()
    
    var body: some View {
        // Use a GeometryReader to get the size of the view
        GeometryReader { geometry in
            // Set up the camera preview
            ZStack {
                PreviewLayerView(previewLayer: self.previewLayer)
                    .id("\(geometry.size.width)x\(geometry.size.height)")
            }
            .onAppear {
                self.previewLayer.frame = geometry.frame(in: .global)
                self.previewLayer.bounds = geometry.frame(in: .global)
                self.previewLayer.session = captureSession
                
                let videoOutput = AVCaptureVideoDataOutput()
                videoOutput.setSampleBufferDelegate(self.cameraDelegate as AVCaptureVideoDataOutputSampleBufferDelegate, queue: DispatchQueue(label: "sample buffer delegate", attributes: []))
                
                guard let device = AVCaptureDevice.default(for: .video) else {
                    fatalError()
                }
                
                if let input = try? AVCaptureDeviceInput(device: device) {
                    captureSession.addInput(input)
                } else {
                    print("camera input error")
                }
                
                if captureSession.canAddOutput(videoOutput) {
                    captureSession.addOutput(videoOutput)
                }
                self.captureSession.startRunning()
            }
            
            // Stop the capture session when the view disappears
            .onDisappear {
                self.captureSession.stopRunning()
            }
            
            
        }
    }
}

struct PreviewLayerView: UIViewRepresentable {
    let previewLayer: AVCaptureVideoPreviewLayer
    
    func makeUIView(context: Context) -> UIView {
        let view = UIView(frame: .zero)
        view.layer.addSublayer(previewLayer)
        return view
    }
    
    func updateUIView(_ uiView: UIView, context: Context) {
        previewLayer.frame = uiView.bounds
    }
}

class CameraDelegate: NSObject, AVCaptureVideoDataOutputSampleBufferDelegate {
  func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
    // Analyze the frame here
      
  }
}