ios - 使用 IOS 相机预览层填充 View

Question

学习教程，我正在尝试进行全屏预览。目前，我的相机看起来很正方形，我相当有信心这可能是一个宽高比问题。相机似乎击中了左右边界。如何将预览固定到导航栏底部和屏幕底部以及两侧？

import UIKit
import AVFoundation

class HomeViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate {

    let captureSession = AVCaptureSession()
    var previewLayer:CALayer!

    var captureDevice:AVCaptureDevice!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        prepareCamera()
    }

    func prepareCamera(){
        captureSession.sessionPreset = AVCaptureSessionPresetPhoto

        if let availableDevices = AVCaptureDeviceDiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaTypeVideo, position: .back).devices {
            captureDevice = availableDevices.first
            beginSession()
        }
    }

    func beginSession () {
        do {
            let captureDeviceInput = try AVCaptureDeviceInput(device: captureDevice)
            captureSession.addInput(captureDeviceInput)
        } catch {
            print(error.localizedDescription)
        }

        if let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession) {
            self.previewLayer = previewLayer
            self.view.layer.addSublayer(self.previewLayer)
            self.previewLayer.frame = self.view.layer.frame
//ADD CONSTRAINTS HERE

            captureSession.startRunning()

            let dataOutput = AVCaptureVideoDataOutput()
            dataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString):NSNumber(value:kCVPixelFormatType_32BGRA)]

            dataOutput.alwaysDiscardsLateVideoFrames = true

            if captureSession.canAddOutput(dataOutput) {
                captureSession.addOutput(dataOutput)
            }

            captureSession.commitConfiguration()

//            let queue = DispatchQueue(label: com.willkie.captureQueue)
//            dataOutput.setSampleBufferDelegate(self, queue: queue)
        }
    }

    func captureOutput(_ captureOutput: AVCaptureOutput!, didDrop sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {

    }

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


}

Answer 1

我认为可能改变你的这个特定行应该有效 -

self.previewLayer.frame = self.view.layer.frame 

到

self.previewLayer.frame = self.view.layer.bounds

此外，只有在上面的代码中调整了框架后，您才应该添加子图层。现在你之前已经添加了。

self.view.layer.addSublayer(self.previewLayer)

还需要加上引力

previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill

如果它仍然不起作用，请将自定义 View 添加到您的 View Controller 并将其设置为您想要显示相机预览的大小，然后您可以使用它 -

self.previewLayer.frame = self.customViewOutlet.layer.bounds