ax-camera

Camera Capture with AVFoundation

Quick Patterns

Basic Session Setup

import AVFoundation

let session = AVCaptureSession()
let photoOutput = AVCapturePhotoOutput()
let sessionQueue = DispatchQueue(label: "camera.session")

sessionQueue.async {
    session.beginConfiguration()
    defer { session.commitConfiguration() }

    session.sessionPreset = .photo

    guard let camera = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back),
          let input = try? AVCaptureDeviceInput(device: camera),
          session.canAddInput(input) else { return }
    session.addInput(input)

    guard session.canAddOutput(photoOutput) else { return }
    session.addOutput(photoOutput)
    photoOutput.maxPhotoQualityPrioritization = .quality

    session.startRunning() // Blocking -- never on main thread
}

SwiftUI Camera Preview

struct CameraPreview: UIViewRepresentable {
    let session: AVCaptureSession

    func makeUIView(context: Context) -> PreviewView {
        let view = PreviewView()
        view.previewLayer.session = session
        view.previewLayer.videoGravity = .resizeAspectFill
        return view
    }
    func updateUIView(_ uiView: PreviewView, context: Context) {}

    class PreviewView: UIView {
        override class var layerClass: AnyClass { AVCaptureVideoPreviewLayer.self }
        var previewLayer: AVCaptureVideoPreviewLayer { layer as! AVCaptureVideoPreviewLayer }
    }
}

Rotation Handling (iOS 17+)

let coordinator = AVCaptureDevice.RotationCoordinator(device: camera, previewLayer: previewLayer)
previewLayer.connection?.videoRotationAngle = coordinator.videoRotationAngleForHorizonLevelPreview

let observation = coordinator.observe(\.videoRotationAngleForHorizonLevelPreview, options: [.new]) { [weak previewLayer] coord, _ in
    DispatchQueue.main.async {
        previewLayer?.connection?.videoRotationAngle = coord.videoRotationAngleForHorizonLevelPreview
    }
}

Capture Photo with Rotation

func capturePhoto() {
    var settings = AVCapturePhotoSettings()
    settings.photoQualityPrioritization = .balanced
    if let connection = photoOutput.connection(with: .video) {
        connection.videoRotationAngle = coordinator.videoRotationAngleForHorizonLevelCapture
    }
    photoOutput.capturePhoto(with: settings, delegate: self)
}