ios - AVCaptureVideoPreviewLayer 方向 - 需要横向

Question

我的应用只有横向。我正在像这样呈现 AVCaptureVideoPreviewLayer:

self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[self.previewLayer setBackgroundColor:[[UIColor blackColor] CGColor]];
[self.previewLayer setVideoGravity:AVLayerVideoGravityResizeAspect];                    
NSLog(@"previewView: %@", self.previewView);
CALayer *rootLayer = [self.previewView layer];
[rootLayer setMasksToBounds:YES];
[self.previewLayer setFrame:[rootLayer bounds]];
    NSLog(@"previewlayer: %f, %f, %f, %f", self.previewLayer.frame.origin.x, self.previewLayer.frame.origin.y, self.previewLayer.frame.size.width, self.previewLayer.frame.size.height);
[rootLayer addSublayer:self.previewLayer];
[session startRunning];

self.previewView的frame为(0,0,568,320)，是正确的。 self.previewLayer 记录帧 (0,0,568,320)，这在理论上是正确的。但是，相机显示在横向屏幕中间显示为纵向矩形，并且相机预览图像的方向错了 90 度。我究竟做错了什么？我需要相机预览层以全屏、横向模式显示，并且图像的方向应该正确。

Answer 1

swift 5.5，Xcode 13.2

private func updatePreviewLayer(layer: AVCaptureConnection, orientation: AVCaptureVideoOrientation) {
    layer.videoOrientation = orientation
    self.previewLayer?.frame = view.bounds
}

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    
    if let connection = self.previewLayer?.connection {
        let currentDevice = UIDevice.current
        let orientation: UIDeviceOrientation = currentDevice.orientation
        let previewLayerConnection: AVCaptureConnection = connection
        
        if previewLayerConnection.isVideoOrientationSupported {
            switch orientation {
            case .portrait: self.updatePreviewLayer(layer: previewLayerConnection, orientation: .portrait)
            case .landscapeRight: self.updatePreviewLayer(layer: previewLayerConnection, orientation: .landscapeLeft)
            case .landscapeLeft: self.updatePreviewLayer(layer: previewLayerConnection, orientation: .landscapeRight)
            case .portraitUpsideDown: self.updatePreviewLayer(layer: previewLayerConnection, orientation: .portraitUpsideDown)
            default: self.updatePreviewLayer(layer: previewLayerConnection, orientation: .portrait)
            }
        }
    }
}

swift 2.2，Xcode 7.3

private func updatePreviewLayer(layer: AVCaptureConnection, orientation: AVCaptureVideoOrientation) {
    
    layer.videoOrientation = orientation

    previewLayer.frame = self.view.bounds

}

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    
    if let connection =  self.previewLayer?.connection  {
        
        let currentDevice: UIDevice = UIDevice.currentDevice()
        
        let orientation: UIDeviceOrientation = currentDevice.orientation
        
        let previewLayerConnection : AVCaptureConnection = connection
        
        if (previewLayerConnection.supportsVideoOrientation) {
            
            switch (orientation) {
            case .Portrait: updatePreviewLayer(previewLayerConnection, orientation: .Portrait)
                                
            case .LandscapeRight: updatePreviewLayer(previewLayerConnection, orientation: .LandscapeLeft)
                                
            case .LandscapeLeft: updatePreviewLayer(previewLayerConnection, orientation: .LandscapeRight)
                                
            case .PortraitUpsideDown: updatePreviewLayer(previewLayerConnection, orientation: .PortraitUpsideDown)
                                
            default: updatePreviewLayer(previewLayerConnection, orientation: .Portrait)
            
            }
        }
    }
}