【Swift】カメラアプリの作り方ご紹介。

import UIKit
import Foundation
import AVFoundation

class ViewController: UIViewController,AVCaptureVideoDataOutputSampleBufferDelegate,UIGestureRecognizerDelegate, AVCapturePhotoCaptureDelegate {

    //カメラ関連　セッション　デバイス　出力
    var session: AVCaptureSession!
    var device: AVCaptureDevice!
    var output: AVCaptureVideoDataOutput!
    //保存用Image
    var saveimg:UIImage? = nil
    // カメラ表示用imageview
    @IBOutlet weak var CameraImageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // カメラの初期設定        
        if initCamera() {
            session.startRunning()
        }else{
            assert(false) //カメラが使えない
        }
        // Do any additional setup after loading the view.
    }
    
    // カメラの準備処理
    func initCamera() -> Bool {
        //解像度 フレームレート カメラ向き
        let preset = AVCaptureSession.Preset.hd4K3840x2160
        let frame = CMTimeMake(value: 1, timescale: 20) //
        let position = AVCaptureDevice.Position.back
        
        setImageViewLayout(preset: preset)//UIImageViewの大きさを調整
        // セッションの作成.
        session = AVCaptureSession()
        // 解像度の指定.
        session.sessionPreset = preset
        // デバイス取得.
        device = AVCaptureDevice.default(AVCaptureDevice.DeviceType.builtInWideAngleCamera,for: AVMediaType.video,position: position)
        //AVCaptureDevice.default(AVCaptureDevice.DeviceType.
        // VideoInputを取得.
        var input: AVCaptureDeviceInput! = nil
        do {
            input = try
                AVCaptureDeviceInput(device: device) as AVCaptureDeviceInput
        } catch let error {
            print(error)
            return false
        }
        // セッションに追加.
        if session.canAddInput(input) {
            session.addInput(input)
        } else {
            return false
        }
        // 出力先を設定
        output = AVCaptureVideoDataOutput()
        //ピクセルフォーマットを設定
        output.videoSettings =
            [ kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String : Int(kCVPixelFormatType_32BGRA) ]
        //サブスレッド用のシリアルキューを用意
    
        output.setSampleBufferDelegate(self, queue: DispatchQueue.main)
        // 遅れてきたフレームは無視する
        output.alwaysDiscardsLateVideoFrames = true
        // FPSを設定
        do {
            try device.lockForConfiguration()
            device.activeVideoMinFrameDuration = frame //フレームレート
            
            device.unlockForConfiguration()
        } catch {
            return false
        }
        // セッションに追加.
        if session.canAddOutput(output) {
            session.addOutput(output)
        } else {
            return false
        }
        // カメラの向きを合わせる
        for connection in output.connections {
            if connection.isVideoOrientationSupported {
                connection.videoOrientation = AVCaptureVideoOrientation.portrait
            }
        }
        return true
    }
    // 画像を出力
    func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
        DispatchQueue.main.async{ [self] in //非同期処理として実行
            let img = self.captureImage(sampleBuffer) //UIImageへ変換
            var resultImg: UIImage //結果を格納する
            resultImg = img
            // 表示
            self.CameraImageView.image = resultImg
            
            saveimg = resultImg
        }
    }

    // 動画のbufferを画像に変換
    func captureImage(_ sampleBuffer:CMSampleBuffer) -> UIImage{
        let imageBuffer: CVImageBuffer! = CMSampleBufferGetImageBuffer(sampleBuffer)

        // ベースアドレスをロック
        CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
        // 画像データの情報を取得
        let baseAddress: UnsafeMutableRawPointer = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0)!
        let bytesPerRow: Int = CVPixelBufferGetBytesPerRow(imageBuffer)
        let width: Int = CVPixelBufferGetWidth(imageBuffer)
        let height: Int = CVPixelBufferGetHeight(imageBuffer)
        // RGB色空間を作成
        let colorSpace: CGColorSpace! = CGColorSpaceCreateDeviceRGB()
        // Bitmap graphic contextを作成
        let bitsPerCompornent: Int = 8
        let bitmapInfo = CGBitmapInfo(rawValue: (CGBitmapInfo.byteOrder32Little.rawValue | CGImageAlphaInfo.premultipliedFirst.rawValue) as UInt32)
        let newContext: CGContext! = CGContext(data: baseAddress, width: width, height: height, bitsPerComponent: bitsPerCompornent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo.rawValue) as CGContext?
        // Quartz imageを作成
        let imageRef: CGImage! = newContext!.makeImage()
        // ベースアドレスをアンロック
        CVPixelBufferUnlockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
        // UIImageを作成
        let resultImage: UIImage = UIImage(cgImage: imageRef)
        saveimg = resultImage

        return resultImage
    }
    // カメラの表示サイズ
    func setImageViewLayout(preset: AVCaptureSession.Preset){
        let width = self.view.frame.width
        var height:CGFloat
        switch preset {
        case .photo:
            height = width * 852 / 640
        case .high:
            height = width * 1280 / 720
        case .medium:
            height = width * 480 / 360
        case .low:
            height = width * 192 / 144
        case .cif352x288:
            height = width * 352 / 288
        case .hd1280x720:
            height = width * 1280 / 720
        default:
            height = self.view.frame.height
        }
        CameraImageView.frame = CGRect(x: 0, y: 0, width: width, height: height)
    }
}

,AVCaptureVideoDataOutputSampleBufferDelegate,UIGestureRecognizerDelegate, AVCapturePhotoCaptureDelegate

//カメラ関連　セッション　デバイス　出力
var session: AVCaptureSession!
var device: AVCaptureDevice!
var output: AVCaptureVideoDataOutput!
//保存用Image
var saveimg:UIImage? = nil