iOS: Capture image from front facing camera

Question

I am making an application where I would like to capture an image from the front facing camera, without presenting a capture screen of any kind. I want to take a picture com

Answer 1

Convert above code to Swift 4

import UIKit
import AVFoundation

class CameraViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {

@IBOutlet weak var cameraImageView: UIImageView!

var device: AVCaptureDevice?
var captureSession: AVCaptureSession?
var previewLayer: AVCaptureVideoPreviewLayer?
var cameraImage: UIImage?

override func viewDidLoad() {
    super.viewDidLoad()

    setupCamera()
    setupTimer()
}

func setupCamera() {
    let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera],
                                                            mediaType: AVMediaType.video,
                                                           position: .front)
    device = discoverySession.devices[0]

    let input: AVCaptureDeviceInput
    do {
        input = try AVCaptureDeviceInput(device: device!)
    } catch {
        return
    }

    let output = AVCaptureVideoDataOutput()
    output.alwaysDiscardsLateVideoFrames = true

    let queue = DispatchQueue(label: "cameraQueue")
    output.setSampleBufferDelegate(self, queue: queue)
    output.videoSettings = [kCVPixelBufferPixelFormatTypeKey as AnyHashable as! String: kCVPixelFormatType_32BGRA]

    captureSession = AVCaptureSession()
    captureSession?.addInput(input)
    captureSession?.addOutput(output)
    captureSession?.sessionPreset = AVCaptureSession.Preset.photo

    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)
    previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
    previewLayer?.frame = CGRect(x: 0.0, y: 0.0, width: view.frame.width, height: view.frame.height)

    view.layer.insertSublayer(previewLayer!, at: 0)

        captureSession?.startRunning()
    }

    func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
        let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
    CVPixelBufferLockBaseAddress(imageBuffer!, CVPixelBufferLockFlags(rawValue: 0))
        let baseAddress = UnsafeMutableRawPointer(CVPixelBufferGetBaseAddress(imageBuffer!))
        let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer!)
        let width = CVPixelBufferGetWidth(imageBuffer!)
        let height = CVPixelBufferGetHeight(imageBuffer!)

        let colorSpace = CGColorSpaceCreateDeviceRGB()
        let newContext = CGContext(data: baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo:
        CGBitmapInfo.byteOrder32Little.rawValue | CGImageAlphaInfo.premultipliedFirst.rawValue)

        let newImage = newContext!.makeImage()
         cameraImage = UIImage(cgImage: newImage!)

        CVPixelBufferUnlockBaseAddress(imageBuffer!, CVPixelBufferLockFlags(rawValue: 0))
    }

    func setupTimer() {
        _ = Timer.scheduledTimer(timeInterval: 2.0, target: self, selector: #selector(snapshot), userInfo: nil, repeats: true)
    }

    @objc func snapshot() {
        print("SNAPSHOT")
        cameraImageView.image = cameraImage
    }
}