AVFoundation的圖層預覽

使用AVFoundation可以用來自定義相機，幾乎全部都得自己定義，在這過程發現預覽圖層的轉向問題，終於找到解決方式

使用這個方法preViewLayer是自己創的預覽圖層

@objc func rotated() {
   if UIDeviceOrientationIsLandscape(UIDevice.current.orientation) {
     if UIDevice.current.orientation ==  UIDeviceOrientation.landscapeLeft {
     preViewLayer.connection?.videoOrientation = AVCaptureVideoOrientation.landscapeRight
    }else {
     preViewLayer.connection?.videoOrientation =  AVCaptureVideoOrientation.landscapeLeft
    }
 }
   if UIDeviceOrientationIsPortrait(UIDevice.current.orientation) {
     if UIDevice.current.orientation == UIDeviceOrientation.portrait{
     preViewLayer.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
   }
    else
  {
     preViewLayer.connection?.videoOrientation = AVCaptureVideoOrientation.portraitUpsideDown
    }
  }
}

然後加個監聽viewDidLoad或viewWillAppear

NotificationCenter.default.addObserver(self, selector: #selector(ViewController.rotated), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)

2018.04.18 更新

使用func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)

修改自Apple simple code

let deviceOrientation = UIDevice.current.orientation
guard let newVideoOrientation = AVCaptureVideoOrientation(rawValue: deviceOrientation.rawValue),
deviceOrientation.isPortrait || deviceOrientation.isLandscape else {
return
}
cameraPreviewlayer?.connection?.videoOrientation = newVideoOrientation
}