def get_colorbar_range(ctl):
    """ Return the range of a color transfer function (ctl) as a list = [min, max]

    I am sure there is a better way of doing this, but for now I am getting the minimum
    and maximum values from the ctl.RGBPoints.
    """
    rgbPoints = ctl.RGBPoints
    min = rgbPoints[0]
    max = rgbPoints[-4]
    return [min, max]