Low Pass Filter android

Question

I am trying to adapt a low pass filter from this site: Low Pass Filter

My problem is that I do not know what is the goal of below line:

int rotation = Compatibility.getRotation(this);

I have googled a lot in order to search information about this but without no luck. Anyone knows what it does?

See below piece of code:

@Override
public void onSensorChanged(SensorEvent evt) {
    if (evt.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
        gravSensorVals = lowPass(evt.values.clone(), gravSensorVals);
    } else if (evt.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {
        magSensorVals = lowPass(evt.values.clone(), magSensorVals);
    }
    if (gravSensorVals != null && magSensorVals != null) {
        SensorManager.getRotationMatrix(RTmp, I, gravSensorVals, magSensorVals);
        int rotation = Compatibility.getRotation(this);
        if (rotation == 1) {
            SensorManager.remapCoordinateSystem(RTmp, SensorManager.AXIS_X, SensorManager.AXIS_MINUS_Z, Rot);
        } else {
            SensorManager.remapCoordinateSystem(RTmp, SensorManager.AXIS_Y, SensorManager.AXIS_MINUS_Z, Rot);
        }
        SensorManager.getOrientation(Rot, results);
        UIARView.azimuth = (float)(((results[0]*180)/Math.PI)+180);
        UIARView.pitch = (float)(((results[1]*180/Math.PI))+90);
        UIARView.roll = (float)(((results[2]*180/Math.PI)));
        radarMarkerView.postInvalidate();
    }
}

Answer 1

From android documentation: here, it will check the device orientation. So value of one is ROTATION_90. device rotated 90 degrees counter clockwise.