如何使用AVFoundation将预览（缩放）图像另存为照片？

因此，我已经解决了如何使用CATransform3DMakeScale（2.4，2.4，2.4）制作缩放效果的问题，但是现在我在尝试保存Zoome预览消息（执行缩放时的代码）时遇到了问题：

 // init camera device
    let captureDevice : AVCaptureDevice? = initCaptureDevice()
    print("camera was initialized")
    // Prepare output
    initOutput()
    if (captureDevice != nil) {
        let deviceInput : AVCaptureInput? = initInputDevice(captureDevice: captureDevice!)
        if (deviceInput != nil) {
            initSession(deviceInput: deviceInput!)
            // Preview Size
            let previewLayer: AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.session)
            previewLayer.frame = self.view.bounds
            previewLayer.transform = CATransform3DMakeScale(2.4, 2.4, 2.4)
             imagePreviewScale = previewLayer.contentsScale
            self.view.layer.addSublayer(previewLayer)
            self.session?.startRunning()

现在，我尝试像这样保存预览的缩放图像：

 let videoConnection : AVCaptureConnection? = self.imageOutput?.connection(withMediaType: AVMediaTypeVideo)
    if (videoConnection != nil) {

        videoConnection?.videoScaleAndCropFactor = imagePreviewScale

        self.imageOutput?.captureStillImageAsynchronously(from: videoConnection, completionHandler: { (imageDataSampleBuffer, error) -> Void in
            if (imageDataSampleBuffer != nil) {
                                    // Capture JPEG

                let imageData : NSData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer) as NSData
                // JPEG
                let image = UIImage(data: imageData as Data)

并添加了线

 imagePreviewScale = previewLayer.contentsScale

但是仍然没有任何反应，请任何人可以告诉我如何保存“精确缩放”的图片？