我注意到，在iOS设备上，默认情况下，视频设备的videoOrientation的{{1}}属性对于前置摄像头是AVCaptureConnection，对于后置摄像头是landscapeLeft。同时，两种情况下的实际像素数据都定向为landscapeRight。据我所知，这不是任何错误，因为我在Apple的sample中找到了以下代码。
landscapeLeft extension PreviewMetalView.Rotation {
init?(with interfaceOrientation: UIInterfaceOrientation, videoOrientation: AVCaptureVideoOrientation, cameraPosition: AVCaptureDevice.Position) {
/*
Calculate the rotation between the videoOrientation and the interfaceOrientation.
The direction of the rotation depends upon the camera position.
*/
switch videoOrientation {
case .portrait:
switch interfaceOrientation {
case .landscapeRight:
if cameraPosition == .front {
self = .rotate90Degrees
} else {
self = .rotate270Degrees
}
case .landscapeLeft:
if cameraPosition == .front {
self = .rotate270Degrees
} else {
self = .rotate90Degrees
}
case .portrait:
self = .rotate0Degrees
case .portraitUpsideDown:
self = .rotate180Degrees
default: return nil
}
case .portraitUpsideDown:
switch interfaceOrientation {
case .landscapeRight:
if cameraPosition == .front {
self = .rotate270Degrees
} else {
self = .rotate90Degrees
}
case .landscapeLeft:
if cameraPosition == .front {
self = .rotate90Degrees
} else {
self = .rotate270Degrees
}
case .portrait:
self = .rotate180Degrees
case .portraitUpsideDown:
self = .rotate0Degrees
default: return nil
}
case .landscapeRight:
switch interfaceOrientation {
case .landscapeRight:
self = .rotate0Degrees
case .landscapeLeft:
self = .rotate180Degrees
case .portrait:
if cameraPosition == .front {
self = .rotate270Degrees
} else {
self = .rotate90Degrees
}
case .portraitUpsideDown:
if cameraPosition == .front {
self = .rotate90Degrees
} else {
self = .rotate270Degrees
}
default: return nil
}
case .landscapeLeft:
switch interfaceOrientation {
case .landscapeLeft:
self = .rotate0Degrees
case .landscapeRight:
self = .rotate180Degrees
case .portrait:
if cameraPosition == .front {
self = .rotate90Degrees
} else {
self = .rotate270Degrees
}
case .portraitUpsideDown:
if cameraPosition == .front {
self = .rotate270Degrees
} else {
self = .rotate90Degrees
}
default: return nil
}
}
}
}
在前后摄像头上的工作方式似乎有所不同，我在文档或网络上找不到任何相关信息。有人知道财产如此奇怪的行为的原因吗？