自定义相机纵横比

Question

I am creating a custom camera view with AVFoundation with following code:

    captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
    captureSession.addOutput(stillOutput)
    if err != nil {
        println("error: \(err?.localizedDescription)")
    }

    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer?.videoGravity=AVLayerVideoGravityResizeAspectFill

And it works well. Then I am capturing and showing image on the screen with following code:

    self.stillOutput.captureStillImageAsynchronouslyFromConnection(videoConnection){
                            (imageSampleBuffer : CMSampleBuffer!, _) in

let imageDataJpeg = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageSampleBuffer)
var pickedImage: UIImage = UIImage(data: imageDataJpeg)!
var previewImageView=UIImageView()
self.previewImageView.frame = CGRect(x:0, y:0, width:UIScreen.mainScreen().bounds.width, height:UIScreen.mainScreen().bounds.height)
self.previewImageView.layer.zPosition = -1
self.view.addSubview(self.previewImageView)

But camera works properly when i want to show preview image it looks like this:

Camera:

After the shot preview:

It should look like the camera view. How can I fix it?

Answer 1

如果要使纵横比为3:4 ，则应设置：

captureSession.sessionPreset = .photo