VideoPreviewController

VideoPreview.swift

import UIKit
import AVFoundation

open class VideoPreview : UIViewController {

	var captureSession: AVCaptureSession!
	var camera: AVCaptureDevice!
	var preview: AVCaptureVideoPreviewLayer!

	func initSession() {
		captureSession = AVCaptureSession()
		captureSession.beginConfiguration()
		captureSession.sessionPreset = .high

		let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back)
		camera = discoverySession.devices[0]

		try! camera.lockForConfiguration()
		camera.focusMode = .continuousAutoFocus
		camera.exposureMode = .continuousAutoExposure
		camera.unlockForConfiguration()

		let cameraInput = try! AVCaptureDeviceInput (device: camera)
		captureSession.addInput(cameraInput)
		captureSession.commitConfiguration()

		preview = AVCaptureVideoPreviewLayer(session: captureSession)
		preview.videoGravity = .resizeAspect
	}

	func updatePreview() {
		preview.connection?.videoOrientation = AVCaptureVideoOrientation(rawValue: UIApplication.shared.statusBarOrientation.rawValue)!
		preview.frame.size = view.frame.size
		// debug
		print("\(self.preview.connection!.videoOrientation.rawValue)")
	}

	override open func viewDidLoad() {
		super.viewDidLoad()
		initSession()
	}

	override open func viewWillAppear(_ animated: Bool) {
		super.viewWillAppear(animated)
		view.layer.addSublayer(preview)
		updatePreview()
		captureSession.startRunning()
	}

	open override func viewWillDisappear(_ animated: Bool) {
		super.viewWillDisappear(animated)
		preview.removeFromSuperlayer()
		captureSession.stopRunning()
	}

	override open func viewWillLayoutSubviews() {
		super.viewWillLayoutSubviews()
		updatePreview()
	}

	/*open override var shouldAutorotate: Bool {
		return false
	}*/

	open override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
		coordinator.animate(alongsideTransition: { context in
			self.updatePreview()
		})
		super.viewWillTransition(to: size, with: coordinator)
	}
}