Camera2 front camera preview rotation

Question

i am working on camera2 and have got a problem with rotation. In some devices, when switching to front camera, preview is being rotated 180 degrees. Was looking such a "setDefaultOrientation()" method for camera2 but couldn't find it.

Thanks

Answer 1

With a GLSurfaceView, you're presumably using a SurfaceTexture to map the camera preview stream into a GL texture, and then rendering it.

The image data in the texture is not automatically rotated to be 'upright' - for one, there's no way for the OS to know how you're going to render your texture.

However, the SurfaceTexture has a getTransformMatrix call, which when connected to the camera2 API, will give you the necessary transform from the camera's orientation to the device's native orientation (typically portrait for phones, landscape for tablets, but not always). You'll then have to add the transform from the native orientation to your app's orientation to this matrix, and then apply the combined matrix transform to adjust the preview image.

Answer 2

you can set the correct image rotation in CaptureRequest object while capturing an image in CameraCaptureSession.StateCallback using CameraCharacterisitics

CameraCharacterisitics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId);

like this.

private CameraCaptureSession.StateCallback sessionStateCallback = new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
  captureSession = session;
  try {
    CaptureRequest.Builder builder = session.getDevice().createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
    builder.addTarget(imageReader.getSurface());
    builder.set(CaptureRequest.JPEG_ORIENTATION, cameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION));
    session.capture(builder.build(), null, backgroundHandler);
  } catch (CameraAccessException e) {
    Log.d("tag", e.getMessage());
  }
}

@Override
public void onConfigureFailed(@NonNull CameraCaptureSession session) {
}
};

Answer 3

you can try this code for open your camera

I hope this will help

public void startPreview() {
    try {
        Log.i(TAG, "starting preview: " + started);

        // ....
        Camera.CameraInfo camInfo = new Camera.CameraInfo();
        Camera.getCameraInfo(cameraIndex, camInfo);
        int cameraRotationOffset = camInfo.orientation;
        // ...

        Camera.Parameters parameters = camera.getParameters();
        List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();
        Camera.Size previewSize = null;
        float closestRatio = Float.MAX_VALUE;

        int targetPreviewWidth = isLandscape() ? getWidth() : getHeight();
        int targetPreviewHeight = isLandscape() ? getHeight() : getWidth();
        float targetRatio = targetPreviewWidth / (float) targetPreviewHeight;

        Log.v(TAG, "target size: " + targetPreviewWidth + " / " + targetPreviewHeight + " ratio:" + targetRatio);
        for (Camera.Size candidateSize : previewSizes) {
            float whRatio = candidateSize.width / (float) candidateSize.height;
            if (previewSize == null || Math.abs(targetRatio - whRatio) < Math.abs(targetRatio - closestRatio)) {
                closestRatio = whRatio;
                previewSize = candidateSize;
            }
        }

        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        int degrees = 0;
        switch (rotation) {
        case Surface.ROTATION_0:
            degrees = 0;
            break; // Natural orientation
        case Surface.ROTATION_90:
            degrees = 90;
            break; // Landscape left
        case Surface.ROTATION_180:
            degrees = 180;
            break;// Upside down
        case Surface.ROTATION_270:
            degrees = 270;
            break;// Landscape right
        }
        int displayRotation;
        if (isFrontFacingCam) {
            displayRotation = (cameraRotationOffset + degrees) % 360;
            displayRotation = (360 - displayRotation) % 360; // compensate
                                                                // the
                                                                // mirror
        } else { // back-facing
            displayRotation = (cameraRotationOffset - degrees + 360) % 360;
        }

        Log.v(TAG, "rotation cam / phone = displayRotation: " + cameraRotationOffset + " / " + degrees + " = "
                + displayRotation);

        this.camera.setDisplayOrientation(displayRotation);

        int rotate;
        if (isFrontFacingCam) {
            rotate = (360 + cameraRotationOffset + degrees) % 360;
        } else {
            rotate = (360 + cameraRotationOffset - degrees) % 360;
        }

        Log.v(TAG, "screenshot rotation: " + cameraRotationOffset + " / " + degrees + " = " + rotate);

        Log.v(TAG, "preview size: " + previewSize.width + " / " + previewSize.height);
        parameters.setPreviewSize(previewSize.width, previewSize.height);
        parameters.setRotation(rotate);
        camera.setParameters(parameters);
        camera.setPreviewDisplay(mHolder);
        camera.startPreview();

        Log.d(TAG, "preview started");

        started = true;
    } catch (IOException e) {
        Log.d(TAG, "Error setting camera preview: " + e.getMessage());
    }
}