Aspect ratio not considering custom sized views / AutoFitSurfaceView is stretched

Hi!

I'm developing an abstraction over the Camera2 API and found this sample to be very useful, so thanks!

I'm currently stuck with one issue though, and I can't seem to resolve that (since 2 days now), I keep finding old Camera (v1) related S/O threads and no answers in this repo's Issues/PRs.

My Preview (SurfaceView/TextureView) is stretched. Here's how it looks:

Preview (using the `AutoFitSurfaceView`)

Actual Photo with resizeMode/scaleType "cover"

as you can see, the first image is really weirdly stretched while the photo being shot is actually in correct dimensions.
I'm _pretty_ sure that the cause of the problem is the `AutoFitSurfaceView` which only uses the display size for aspect ratio calculation, but that obviously doesn't work if the `SurfaceView` is not the same size as the phone display, as seen in my screenshot. (Bottom Bar & Status Bar takes away some space)

I thought maybe someone here would be so kind to help me out here. 😄

Thanks!

**EDIT**

Some extra context: I create the `AutoFitSurfaceView` in my custom view's `init`, but I also tried the `onAttachedToWindow` and got the same result. I don't have a Fragment or Activity in this context, since I'm writing a react native library.

Anyways, here's how I initialize the `AutoFitSurfaceView`:

```kt
class CameraView(context: Context) : FrameLayout(context) {

// ...

init {
// ...

surfaceView = AutoFitSurfaceView(context)
surfaceView.layoutParams = LayoutParams(
LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT)
surfaceView.holder.addCallback(object: SurfaceHolder.Callback {
override fun surfaceDestroyed(holder: SurfaceHolder) = Unit
override fun surfaceChanged(holder: SurfaceHolder, format: Int, width: Int, height: Int) = Unit
override fun surfaceCreated(holder: SurfaceHolder) {
// Selects appropriate preview size and configures view finder
val previewSize = getPreviewOutputSize(surfaceView.display, characteristics, SurfaceHolder::class.java)
Log.d(REACT_CLASS, "View finder size: ${surfaceView.width} x ${surfaceView.height}")
Log.d(REACT_CLASS, "Selected preview size: $previewSize")
surfaceView.setAspectRatio(previewSize.width, previewSize.height)

// To ensure that size is set, initialize camera in the view's thread with the found previewSize
surfaceView.post { configureSession(previewSize) }
}
})
addView(surfaceView)

// ...
```

Also, I found [this answer on a similar Stackoverflow question](https://stackoverflow.com/a/22758359/5281431) which creates a custom subclass of the SurfaceView which should automatically resize with the Camera - but this doesn't use the Camera2 API, I think that's the old Camera 1 API which won't work for me.

Start with AutoFitSurfaceView and the CameraView initialization shown in the issue, then trace getPreviewOutputSize and the call to setAspectRatio. Reproduce the stretched preview with a custom-sized view and compare its dimensions with the selected preview size; done means the preview preserves the camera image's aspect ratio in that layout.

Written by the indexing model from the issue text.