Save our mad hattery to photos library

LiveCaptureHattingViewController.swift

extension LiveCaptureHattingViewController {
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?)
    {
        takeScreenShot()
    }
    
    func takeScreenShot()
    {
        guard let currentPixelBuffer = currentPixelBuffer else {
            return
        }
        
        let frame = CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.size.height)
        let photoView = UIView(frame: frame)
        let imageView = UIImageView(frame: frame)
        imageView.image = imageFromBuffer(buffer: currentPixelBuffer)
        imageView.contentMode = UIViewContentMode.scaleAspectFill
        photoView.addSubview(imageView)
        hats.forEach{ photoView.addSubview($0) }
        
        UIGraphicsBeginImageContext(photoView.frame.size)
        photoView.layer.render(in: UIGraphicsGetCurrentContext()!)
        let imageRef = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        UIImageWriteToSavedPhotosAlbum(imageRef!, nil, nil, nil)
    }
    
    private func imageFromBuffer(buffer: CMSampleBuffer) -> UIImage?
    {
        guard let imageBuffer = CMSampleBufferGetImageBuffer(buffer) else { return nil }
        let ciImage = CIImage(cvPixelBuffer: imageBuffer)
        guard let cgImage = CIContext().createCGImage(ciImage, from: ciImage.extent) else { return nil }
        return UIImage(cgImage: cgImage)
    }
}