如何在CameraX中镜像PreviewView?

免责声明:我知道存在这个问题，但是目前立场尚未解决，我正在尝试提供更多信息，而又不会污染那些无用的答案的问题，反正也无法解决问题.

Disclaimer: I'm aware of the existence of this question, but it currently stands unresolved and I'm trying to provide extra information without polluting that one with useless answers that won't solve the problem anyway.

我有一个带有前置摄像头的自定义设备，该摄像头默认情况下是镜像的，因此我想正常显示预览，并且需要水平翻转PreviewView的内容，但是我被卡住了.过去其他人建议使用 PreviewView#setScaleX(-1)，但是它要么根本不起作用，要么需要在代码中的特定位置调用，而我还没有还没找到.

I have a custom device with a front camera that is mirrored by default, so I want to display the preview normally and I need to horizontally flip the content of PreviewView, but I'm stuck. Other people in the past have suggested using PreviewView#setScaleX(-1) but it either doesn't work at all or it needs to be called at a very specific point in the code, which I haven't found yet.

下面的代码是官方

The code below is a simplified version of CameraFragment.kt in the official CameraXBasic example; I've added comments where I've already tired calling viewFinder.scaleX = -1f with no success. Honestly I don't really think that the place makes a difference because if I call it with any value other than 1 it works fine with both scaleX and scaleY, but it always ignores the negative sign so it never flips.

private lateinit var viewFinder: PreviewView

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    ...
    viewFinder = view.findViewById(R.id.view_finder)
    // HERE
    viewFinder.post {
        // HERE
        setupCamera()
    }
}

private fun setupCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(requireContext())
    cameraProviderFuture.addListener(Runnable {
        val cameraProvider = cameraProviderFuture.get()

        val cameraSelector = CameraSelector.Builder()
            .requireLensFacing(CameraSelector.LENS_FACING_FRONT)
            .build()

       val preview = Preview.Builder()
            .build()
            .also {
                // HERE
                it.setSurfaceProvider(viewFinder.surfaceProvider)
            }

       cameraProvider.unbindAll()

        try {
            cameraProvider.bindToLifecycle(this, cameraSelector, preview)
            // HERE
        } catch (exc: Exception) {
            Log.e(TAG, "Use case binding failed", exc)
        }
        // HERE
    }, ContextCompat.getMainExecutor(requireContext()))
    // HERE
}