Provides different colormaps for different visualization types.

def get_freesurfer_cmap(vis_type):
    """Provides different colormaps for different visualization types."""

    if vis_type in ('cortical_volumetric', 'cortical_contour'):
            LUT = get_freesurfer_cortical_LUT()
            cmap = ListedColormap(LUT)
    elif vis_type in ('labels_volumetric', 'labels_contour'):
        black = np.array([0, 0, 0, 1])
        cmap = plt.get_cmap('hsv')
        # TODO using more than 20 labels might be a problem?
        cmap = cmap(np.linspace(0, 1, 20))
        # prepending black to paint background as black
        colors = np.vstack((black, cmap))
        cmap = ListedColormap(colors, 'my_colormap')
    else:
        raise NotImplementedError('color map for the visualization type {} has not been implemented!'.format(vis_type))

    return cmap