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javaandroidandroid-cameraxautoexposurecompensation

Android CameraX - manually change exposure compensation?

I'm using CameraX for my project. I have created preview useCase and capture useCase.

final CameraSelector cameraSelector = new CameraSelector.Builder().requireLensFacing(lensFacing).build();

        previewBuilder = new Preview.Builder()
            .setTargetResolution(targetOutputSize)
            .setTargetRotation(rotation);

        preview = previewBuilder.build();

        final ImageCapture.Builder imageCaptureBuilder = new ImageCapture.Builder()
            .setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
            .setTargetResolution(targetOutputSize)
            .setTargetRotation(rotation);

        imageCapture = imageCaptureBuilder.build();

Everything works fine. Now, I need to add functionality to manually change exposure compensation, but I can't find any reference in official documentation or anywhere else how to do this. Is it possible with CameraX, or I need to switch to Camera2 API?

Please, any help is welcome.

Solution

  • There is new version of CameraX library.

    def camerax_version = '1.0.0-beta09'

    Firstly add those dependencies to gradle file.

    // CameraX core library
implementation "androidx.camera:camera-core:$camerax_version"

// CameraX Camera2 extensions
implementation "androidx.camera:camera-camera2:$camerax_version"

    This version supports Exposure compensation which can be adjusted in runtime. First create preview and takePicure use cases, and then bind those use cases to cameraProvider.

     camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview, imageCapture);

    Now we have camera instance and it can be used to retrive CameraInfo, and from CameraInfo, we retrive ExposureState.

    ExposureState exposureState = camera.getCameraInfo().getExposureState();

    We can use exposureState to check if exposure compensation is supported on device

    if (!exposureState.isExposureCompensationSupported()) return;

    Next we need to get ExposureCompensation Range

    Range<Integer> range = exposureState.getExposureCompensationRange();

    Finally, we can set ExposureCompensation index in following way

     if (range.contains(index))
     camera.getCameraControl().setExposureCompensationIndex(index);