Capture current camera image using AVFoundation

Question

I'm trying to capture the image and save it to a variable when I press "myButton". What should I do?

My code is as follows:

import UIKit
import AVFoundation
import MobileCoreServices

class ViewController: UIViewController {

    let captureSession = AVCaptureSession()
    var previewLayer : AVCaptureVideoPreviewLayer?
    var captureDevice : AVCaptureDevice?
    @IBOutlet var myTap: UITapGestureRecognizer!
    @IBOutlet weak var myButton: UIButton!

    @IBAction func shotPress(sender: UIButton) {
        //Save image to variable somehow
        })
        var stillImageOutput = AVCaptureStillImageOutput()
        stillImageOutput.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]

        if captureSession.canAddOutput(stillImageOutput) {
            captureSession.addOutput(stillImageOutput)
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        captureSession.sessionPreset = AVCaptureSessionPresetHigh
        let devices = AVCaptureDevice.devices()
        for device in devices {
            if (device.hasMediaType(AVMediaTypeVideo)) {
                if(device.position == AVCaptureDevicePosition.Back) {
                    captureDevice = device as? AVCaptureDevice
                    if captureDevice != nil {
                        beginSession()
                    }
                }
            }
        }
    }

    func updateDeviceSettings(focusValue : Float, isoValue : Float) {
        if let device = captureDevice {
            if(device.lockForConfiguration(nil)) {
                device.focusMode = AVCaptureFocusMode.ContinuousAutoFocus
                device.unlockForConfiguration()
            }
        }
    }

    func beginSession() {
        var err : NSError? = nil
        captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
        if err != nil {
            println("error: \(err?.localizedDescription)")
        }
        previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        self.view.layer.addSublayer(previewLayer)
        self.view.bringSubviewToFront(myButton)
        previewLayer?.frame = self.view.layer.frame
        captureSession.startRunning()
    }

}

Answer 1

Updated for Swift 3:

 var stillImageOutput = AVCaptureStillImageOutput.init()
 stillImageOutput.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
 self.cameraSession.addOutput(stillImageOutput)

 if let videoConnection = stillImageOutput.connection(withMediaType:AVMediaTypeVideo){
     stillImageOutput.captureStillImageAsynchronously(from:videoConnection, completionHandler: {
     (sampleBuffer, error) in
     var imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
     var dataProvider = CGDataProvider.init(data: imageData as! CFData)
     var cgImageRef = CGImage.init(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: .defaultIntent)
     var image = UIImage.init(cgImage: cgImageRef!, scale: 1.0, orientation: .right)
     // do something with image
    })
 }

Answer 2

This is what I am using on one of the app that I am working on. Should be helpful for your problem as well.

func capturePicture(){

    println("Capturing image")
    stillImageOutput.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
    captureSession.addOutput(stillImageOutput)

    if let videoConnection = stillImageOutput.connectionWithMediaType(AVMediaTypeVideo){
            stillImageOutput.captureStillImageAsynchronouslyFromConnection(videoConnection, completionHandler: {
                    (sampleBuffer, error) in
                var imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
                var dataProvider = CGDataProviderCreateWithCFData(imageData)
                var cgImageRef = CGImageCreateWithJPEGDataProvider(dataProvider, nil, true, CGColorRenderingIntent.RenderingIntentDefault)
                var image = UIImage(CGImage: cgImageRef, scale: 1.0, orientation: UIImageOrientation.Right)

                var imageView = UIImageView(image: image)
                imageView.frame = CGRect(x:0, y:0, width:self.screenSize.width, height:self.screenSize.height)

                //Show the captured image to
                self.view.addSubview(imageView)

                //Save the captured preview to image
                UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)

                })
        }
}