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

I converted the code above from Objc to Swift 3, if anyone still looks for a solution in 2017.

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 = AVCaptureDeviceDiscoverySession(deviceTypes: [.builtInWideAngleCamera],
                                                           mediaType: AVMediaTypeVideo,
                                                           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: kCVPixelFormatType_32BGRA]

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

    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill

    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(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
    let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
    CVPixelBufferLockBaseAddress(imageBuffer!, CVPixelBufferLockFlags(rawValue: .allZeros))
    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: .allZeros))
}

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

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

Also, I found a shorter solution for getting the image from the CMSampleBuffer:

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
    let myPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
    let myCIimage = CIImage(cvPixelBuffer: myPixelBuffer!)
    let videoImage = UIImage(ciImage: myCIimage)
    cameraImage = videoImage
}