ios - 自定义相机纵横比

Question

我正在使用 AVFoundation 使用以下代码创建自定义相机 View :

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

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

而且效果很好。然后我使用以下代码在屏幕上捕获并显示图像:

    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)

但是当我想显示预览图像时相机工作正常，它看起来像这样:

相机:

拍摄预览后:

它应该看起来像相机 View 。我该如何解决？

Answer 1

如果你想制作宽高比3:4你应该设置:

captureSession.sessionPreset = .photo