CameraViewController.swift

//
//  CameraViewController.swift
//  CameraTest
//
//  Created by Reona Kubo on 2019/07/08.
//  Copyright © 2019 Reona Kubo. All rights reserved.
//

import UIKit
import AVFoundation

class CameraViewController: UIViewController {

    private var avSession: AVCaptureSession!
    private var avDevice: AVCaptureDevice!
    private var avInput: AVCaptureInput!
    private var avOutput: AVCapturePhotoOutput!

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

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        self.initCamera()
    }

    deinit {
        avSession.stopRunning()
        for output in avSession.outputs {
            avSession.removeOutput(output)
        }

        for input in avSession.inputs {
            avSession.removeInput(input)
        }
        avOutput = nil
        avInput = nil
        avDevice = nil
        avSession = nil
    }

    private func initCamera() {
        // AVキャプチャセッッション
        avSession = AVCaptureSession()
        if(avSession.canSetSessionPreset(AVCaptureSession.Preset.photo)){
            avSession.beginConfiguration()
            /* Highのときは9:16で撮影される
             Photoのときは 3:4 で撮影される*/
            avSession.sessionPreset = AVCaptureSession.Preset.photo
            avSession.commitConfiguration()
        }

        // ここを .front .back で前面・背面カメラを変更
        let devicePosition: AVCaptureDevice.Position = .back
        // AVキャプチャデバイス
        let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera, .builtInTelephotoCamera], mediaType: .video, position: devicePosition)
        for device in discoverySession.devices {
            if device.position == devicePosition {
                avDevice = device
            }
        }
        showCamera()
    }

    private func showCamera() {
        guard let avDevice = avDevice else { return }
        do {
            avInput = try AVCaptureDeviceInput.init(device:avDevice)
        } catch {
            print(error)
            return
        }
        // AVキャプチャデバイスインプットをセッションに追加
        if(avSession.canAddInput(avInput)){
            avSession.addInput(avInput)
            avOutput = AVCapturePhotoOutput()

            if(avSession.canAddOutput(avOutput)){
                avSession.addOutput(avOutput)
            }
        }

        // 画像を表示するレイヤーを生成
        let capVideoLayer: AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: avSession)
        capVideoLayer.videoGravity = .resizeAspectFill
        capVideoLayer.frame = view.frame
        view.layer.addSublayer(capVideoLayer)
        avSession.startRunning()
    }

}