volume_rgba ( self,  data_value=None )

Find the closest displayed data color for the given data value. If no data value is given, use the color for the lowest threshold. Otherwise use the color of the first surface level below the data value if surfaces are shown. If not level is below the data level use the color of the lowest surface. For the interpolated solid use the interpolated color for the data component, or if the data value is outside the threshold range, use the closest endpoint color.