为什么Camera图像的某些部分位于其视图范围之外？

Question

我已经设置了一个UIView，其中将显示相机。一切正常，但是当我将AVCaptureVideoPreviewLayer的videoGravity设置为AVLayerVideoGravityResizeAspectFill时，似乎有些顶级＆amp;在点击的照片中也可以看到相机视图框外的底部部分。请参阅附图（https://i.stack.imgur.com/tDErR.jpg）

我尝试设置clipsToBounds = true但它似乎没有解决问题。

这是我的代码..

import UIKit
import AVFoundation

class ViewController: UIViewController {
@IBOutlet weak var previewView: UIView!
@IBOutlet weak var capturedImage: UIImageView!
var session: AVCaptureSession?
var stillImageOutput: AVCaptureStillImageOutput?
var videoPreviewLayer: AVCaptureVideoPreviewLayer?

override func viewDidLoad() {
    super.viewDidLoad()
    self.previewView.clipsToBounds = true
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    configureCamera()
}
func configureCamera(){
    session = AVCaptureSession()
    session!.sessionPreset = AVCaptureSessionPresetPhoto
    let backCamera = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
    var error: NSError?
    var input: AVCaptureDeviceInput!
    do {
        input = try AVCaptureDeviceInput(device: backCamera)
    } catch let error1 as NSError {
        error = error1
        input = nil
        print(error!.localizedDescription)
    }
    if error == nil && session!.canAddInput(input) {
        session!.addInput(input)
        stillImageOutput = AVCaptureStillImageOutput()
        stillImageOutput?.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
        if session!.canAddOutput(stillImageOutput) {
            session!.addOutput(stillImageOutput)
            videoPreviewLayer = AVCaptureVideoPreviewLayer(session: session)
            videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
            videoPreviewLayer!.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
            let rootLayer :CALayer = self.previewView.layer
            rootLayer.masksToBounds = true
            videoPreviewLayer?.frame = rootLayer.bounds
            videoPreviewLayer?.masksToBounds = true
            rootLayer.addSublayer((videoPreviewLayer)!)
            rootLayer.borderColor = UIColor.green.cgColor
            rootLayer.borderWidth = 2.0
            self.previewView.clipsToBounds = true
            session!.startRunning()
        }
     }
}
@IBAction func btnTakePhoto(_ sender: AnyObject) {
    let videoConnection = stillImageOutput!.connection(withMediaType: AVMediaTypeVideo)
    if(videoConnection != nil) {
        stillImageOutput?.captureStillImageAsynchronously(from: videoConnection, completionHandler: { (sampleBuffer, error) -> Void in
            if sampleBuffer != nil {
                let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer)
                let dataProvider = CGDataProvider(data: imageData as! CFData)
                let cgImageRef = CGImage.init(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: CGColorRenderingIntent.relativeColorimetric)

                let image = UIImage(cgImage: cgImageRef!, scale: 1.0, orientation: UIImageOrientation.right)
                self.capturedImage.image = image
                self.session!.stopRunning()

            }
        })
    }
}
override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    videoPreviewLayer!.frame = self.previewView.layer.bounds
    self.previewView.clipsToBounds = true

}
}

请注意，我不想使用任何其他视频游戏，如AVLayerVideoGravityResizeAspect.Please有人帮助我。我很挣扎。