I'm trying to implement a camera-based barcode scanner on Android (using CameraX and MLKit). I want ...

# android

[Lukasz Kalnik]

I'm trying to implement a camera-based barcode scanner on Android (using CameraX and MLKit). I want to limit the recognized barcodes to a viewfinder frame in the center of the screen, but the returned bounding box has quite weird coordinates, and I don't know how to convert them to match the viewfinder coordinates.
The viewfinder view (and the whole camera screen) is in Compose.

[Chrimaeon]

Better try in #compose-android

[Robert Maged]

try LifecycleCameraController and wrap you analyzer in MlkitAnalyzer, this may help you with coordinates transformation.

[Lukasz Kalnik]

Thank you, I will try this!

[Lukasz Kalnik]

Turned out indeed using LifecycleCameraController and MlKitAnalyzer with CameraController.COORDINATE_SYSTEM_VIEW_REFERENCED fixed the problem!
Then (I'm using Compose) I just had to translate the pixel coordinates from the camera to dp units using LocalDensity.current.
Thanks again for your valuable suggestion.
Also this article explains very well the separation of responsibilities in CameraX between PreviewView and `CameraController`:
https://medium.com/androiddevelopers/camerax-learn-how-to-use-cameracontroller-e3ed10fffecf

[Lukasz Kalnik]

Example solution in Compose in this StackOverflow answer:
https://stackoverflow.com/a/77698616/4990683

[Robert Maged]

I'm glad it helped you resolve the issue! Thanks for sharing your experience.