AVCaptureDevice - Tap-to-Focus feature (iOS)

TapToFocus.swift

@IBAction func handleTapToFocus(sender: UITapGestureRecognizer) {
    if let device = captureDevice {
        let focusPoint = sender.locationInView(previewView)
        let focusScaledPointX = focusPoint.x / previewView.frame.size.width
        let focusScaledPointY = focusPoint.y / previewView.frame.size.height
        if device.isFocusModeSupported(.AutoFocus) && device.focusPointOfInterestSupported {
            do {
                try device.lockForConfiguration()
            } catch {
                print("ERROR: Could not lock camera device for configuration")
                return
            }
             
            device.focusMode = .AutoFocus
            device.focusPointOfInterest = CGPointMake(focusScaledPointX, focusScaledPointY)
                
            device.unlockForConfiguration()
        }
    }
}