Using multiple bokeh HoverTool instances together with the models API

Question

I'd like to use multiple Hovertools in one plot together with Hovertool's names attribute to selectivly apply each tool. Take for instance

hover1 = HoverTool(tooltips=[("group", "1")], names = ['line1'])
hover2 = HoverTool(tooltips=[("group", "2")], names = ['lines2'])

and the two data sources:

source1 = ColumnDataSource(data=dict(
xs=[[1, 3, 2], [3, 4, 6, 6]],
ys=[[2, 1, 4], [4, 7, 8, 5]], 
))

source2 = ColumnDataSource(data=dict(
xs=[[1, 3, 2], [6, 7, 9, 8]],
ys=[[-1, 0, 1], [1, 1, 2, 1]]
))

I'd though the following (using the bokeh.models API) should do what I want

p = figure(plot_width=400, plot_height=400)
l1 = MultiLine(xs='xs', ys='ys', name='lines1')
l2 = MultiLine(xs='xs', ys='ys', name='lines2')
p.add_tools(hover)
p.add_tools(hover2)
p.add_glyph(source1, l1)
p.add_glyph(source2, l2)
show(p)

Alas the Hovertools in the resulting plot do not work (i.e. no tooltips are shown). Using the bokeh.plotting API as follows and everything works as expected:

p = figure(plot_width=400, plot_height=400, tools=[hover, hover2])
p.multi_line(xs='xs', ys='ys', source=source1, name='lines1')
p.multi_line(xs='xs', ys='ys', source=source2, name='lines2')
show(p)

Question: How does one replicate the result of the bokeh.plotting API with the bokeh.models API?

You can have more than one renderer on one `Hovertool`. But you can´t use more than one `Hovertool` on the same plot, as far as I know. You can customise you hover tooltips with a callback called `CustomJSHover`. Check the documentation — ChesuCR, Jun 13 '18 at 11:43
@ChesuCR When using the plotting API there is a warning about duplicate tools but using multiple `HoverTool`s otherwise seems to work all right (there is even an individual icon in the toolbar for each `HoverTool` that allows enabling/disabling it individually). — Sascha, Jun 13 '18 at 11:53
See [this Q&A](https://stackoverflow.com/a/34534995/9629533) for the use of multiple hover tools as well. — Sascha, Jun 13 '18 at 11:58
Ah!! Good to know. I have tried to make that work time ago and it didn´t work, maybe I had used a different tool. Anyway check if my answer that I have written is useful for you — ChesuCR, Jun 13 '18 at 22:13

ChesuCR · Accepted Answer · 2018-06-13T22:41:50.073

The names attribute of the HoverTool model in the Bokeh Documentation:

names: property type: List ( String )

A list of names to query for. If set, only renderers that have a matching value for their name attribute will be used.

With this

l1 = MultiLine(xs='xs', ys='ys', name='lines1')

You are assigning the name to the Multiline object and that is a glyph, not a renderer. So try this instead

from bokeh.io import output_notebook, show
output_notebook()

import numpy as np
from bokeh.plotting import figure
from bokeh.models.sources import ColumnDataSource
from bokeh.models.glyphs import MultiLine
from bokeh.layouts import row
from bokeh.models.tools import HoverTool

source = ColumnDataSource(data=dict(
        xs1=[[1, 2, 3], [5, 6, 7]],
        ys1=[[1, 2, 3], [6, 5, 7]],
        xs2=[[7, 8, 9], [1, 2, 3]],
        ys2=[[4, 5, 7], [6, 7, 2]],
    )
)

hover1 = HoverTool(tooltips=[("group", "1")], names = ['lines1'])
hover2 = HoverTool(tooltips=[("group", "2")], names = ['lines2'])

p = figure(plot_width=400, plot_height=400)
l1 = MultiLine(xs='xs1', ys='ys1')
l2 = MultiLine(xs='xs2', ys='ys2')
r1 = p.add_glyph(source, l1, name='lines1')  # the name is assigned to the renderer
r2 = p.add_glyph(source, l2, name='lines2')
# r1.name = 'lines1'  # or you could assign the name like this as well
# r2.name = 'lines2'

p.add_tools(hover1)
p.add_tools(hover2)

# p = figure(plot_width=400, plot_height=400, tools=[hover1, hover2])
# p.multi_line(xs='xs1', ys='ys1', source=source, name='lines1')
# p.multi_line(xs='xs2', ys='ys2', source=source, name='lines2')


show(p)

Works like a charm! Thanks a lot not only for taking time to find a solution but also explaining the solution :) — Sascha, Jun 14 '18 at 06:35
Nice!! Mark the post as the correct answer if it works. Thank you — ChesuCR, Jun 14 '18 at 08:34
@ChesuCR I am getting the following error. It doesn't seem to be accepting a list. Tried with plain string but it didn't work. It's been a while since you posted this so I am assuming things have changed in Bokeh 3.2.1 Error: ValueError: failed to validate HoverTool(id='p1010', ...).name: expected either None or a value of type String, got ['line1'] — Gopinath S, Aug 03 '23 at 01:55
Ah you are right, they should have changed that at some point. I may update the answer in the future. Thanks — ChesuCR, Aug 08 '23 at 06:23

Using multiple bokeh HoverTool instances together with the models API

1 Answers1