Single Legend for GlyphRenderers on Multiple Plots

I have tried to make this work

from bokeh.models import ColumnDataSource, CDSView, IndexFilter
from bokeh.palettes import Reds3
from bokeh.layouts import row
from bokeh.plotting import curdoc, figure
from bokeh.models.annotations import Legend
import numpy as np

plot_1 = figure(
    width=300,
    height=300,
    tools="pan,box_zoom,box_select,wheel_zoom,tap,save,reset,crosshair",
    toolbar_location='left',
)

plot_2 = figure(
    width=430,
    height=300,
    tools="pan,box_zoom,box_select,wheel_zoom,tap,save,reset,crosshair",
    toolbar_location='left',
)

x = list(range(0,10))
y = np.random.random_integers(200, size=(10))
l = np.random.random_integers(3, size=(10))

x2 = list(range(0,10))
y2 = np.random.random_integers(200, size=(10))
l2 = np.random.random_integers(3, size=(10))

source = ColumnDataSource(data=dict(x=x, y=y, x2=x2, y2=y2))

view_1 = CDSView(
    source=source,
    filters=[IndexFilter([0, 1, 2, 3])]
)

view_2 = CDSView(
    source=source,
    filters=[IndexFilter([5, 6, 7])]
)

view_3 = CDSView(
    source=source,
    filters=[IndexFilter([8, 9, 4])]
)

circle_1 = plot_1.circle(
    x='x',
    y='y',
    size=5,
    fill_alpha=1,
    line_color=None,
    fill_color=Reds3[0],
    source=source,
    view=view_1,
)

circle_2 = plot_1.circle(
    x='x',
    y='y',
    size=5,
    fill_alpha=1,
    line_color=None,
    fill_color=Reds3[1],
    source=source,
    view=view_2,
)

circle_3 = plot_1.circle(
    x='x',
    y='y',
    size=5,
    fill_alpha=1,
    line_color=None,
    fill_color=Reds3[2],
    source=source,
    view=view_3,
)

view_4 = CDSView(
    source=source,
    filters=[IndexFilter([0, 1, 2, 3])]
)

view_5 = CDSView(
    source=source,
    filters=[IndexFilter([5, 6, 7])]
)

view_6 = CDSView(
    source=source,
    filters=[IndexFilter([8, 9, 4])]
)

circle_4 = plot_2.circle(
    x='x',
    y='y',
    size=5,
    fill_alpha=1,
    fill_color=Reds3[0],
    line_color=None,
    source=source,
    view=view_4,
)

circle_5 = plot_2.circle(
    x='x',
    y='y',
    size=5,
    fill_alpha=1,
    fill_color=Reds3[1],
    line_color=None,
    source=source,
    view=view_5,
)

circle_6 = plot_2.circle(
    x='x',
    y='y',
    size=5,
    fill_alpha=1,
    fill_color=Reds3[2],
    line_color=None,
    source=source,
    view=view_6,
)

legend = Legend(
    items=[
        ("LEGEND 1", [circle_4]),
        ("LEGEND 2", [circle_5]),
        ("LEGEND 3", [circle_3, circle_6]),  # renderers for several plots
    ],
    location=(10, 0)
)
plot_2.add_layout(legend, 'right')
plot_2.legend.click_policy = 'hide'

curdoc().add_root(row([plot_1, plot_2]))

I think this is not possible because the legend is usually added to one plot plot.add_layout(legend, 'right'). Anyway I have run an example and the glyphs have become invisible on both plots. But I get this error on JavaScript Cannot read property 'draw_legend' of undefined and the color on the legend box is not visible.

So I write this as a feature request. I think It would be useful to have more flexibility on the Legends objects.

[johnrbnsn]

Not a high priority but we can try to consider it at some point

I’d like to say, one of the main reasons I chose Bokeh was your linked plot support. Having large amounts of data on multiple plots, the interactive legend working between them would be a huge benefit for me.

[matheusrmorgado]

Not a high priority but we can try to consider it at some point

It would be very interesting if this resource exists. It would also help me a lot.