ios swift方形照片取景器

Question

I am making a custom camera view controller using AVFoundation frameworks in Swift 4/iOS 11/Xcode 9.1

My code for setUpCaptureSession: (credit to brian voong of letsbuildthatapp.com , I have followed his IG/firebase tutorial and made extensive use of his work!)

fileprivate func setupCaptureSession() {
    let captureSession = AVCaptureSession()

    //setup inputs
    let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

    do {
        let input = try AVCaptureDeviceInput(device: captureDevice!)
        if captureSession.canAddInput(input) {
            captureSession.addInput(input)
        }
    } catch let err {
        debugPrint(err)
    }
    //setup outputs

    if captureSession.canAddOutput(output) {
        captureSession.addOutput(output)
    }
    //setup output preview
    let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer.frame = photoPreView.frame
    view.layer.addSublayer(previewLayer)

    captureSession.startRunning()

}

photoPreView is a view I manually added to the storyboard with aspect ratio 1:1. my issue is visible in this screenshot below:

The capture session is indeed within photoPreView.frame but I want the capture session to fill up the entire area and zoom in , much like how the square mode of the native iOS camera works, or how Instagram's photo capture appears as well.

Answer 1

在捕获图层上，您应该设置...

previewLayer.videoGravity = .resizeAspectFill