bokeh tooltip

    plot_figure = figure(
        title='embedding plot',
        plot_width=700,
        plot_height=400,
        tools=('pan, wheel_zoom, reset, tap, box_select'),
        output_backend="webgl"
    )

    color_col = 'curr_label'
    cids = class_names#db_df[color_col].unique() # really should be class
    # cids = (["-1"] if "-1" in cids else []) + [x for x in np.random.permutation(cids) if x != "-1"]
    # colors = Magma256[::len(Magma256)//len(cids)][:len(cids)]
    # color_mapping = CategoricalColorMapper(factors=cids,palette=colors)
    # clr = dict(field='color_col', transform=color_mapping)
    clr = factor_cmap(color_col, palette=Category20[len(cids)], factors=cids, )

    db_scatter = plot_figure.circle(x='x', y='y', radius=4, radius_units='screen', fill_alpha=.8,
                                    legend_field='orig_label',color=clr, source=db_cds)

    selected_circle = Circle(fill_alpha=1., fill_color=clr, line_alpha=1.)
    nonselected_circle = Circle(fill_alpha=1., fill_color=clr, line_alpha=0.)

    db_scatter.selection_glyph = selected_circle
    db_scatter.nonselection_glyph = nonselected_circle

    plot_figure.add_tools(HoverTool(tooltips="""
    <div style="border: 1px solid;border-radius: 5px;padding:2px;margin:2px">
        <div>
            <img src="@image_url" style='float: center; margin: 5px 5px 5px 5px; padding:1px; width:100%; height:100%; object-fit: contain'/>
        </div>
        <div>
            <span style='font-size: 16px; color: #224499'>Label: @curr_label</span>
            <br/>
            <span style='font-size: 16px; color: #224499'>Orig. Label: @orig_label</span>
            <br/>
            <span style='font-size: 16px; color: #224499'>Id: @index</span>
        </div>
    </div>
    """, renderers=[db_scatter]))


    from bokeh.models import WheelZoomTool
    plot_figure.toolbar.active_scroll = plot_figure.select_one(WheelZoomTool)