multi_line hover in bokeh

Question

As in this question:

I found that hovertool is not implemented for multi_line plots which is a bit of a setback. This is mentioned under 'warnings' here: http://docs.bokeh.org/en/0.11.0/docs/reference/models/tools.html#bokeh.models.tools.HoverTool

Is there any work arounds for this? Also, If I were to implement this feature, what would be a good place to start and is there anything specific to be aware of? Also, is this feature in the current Bokeh roadmap?

As it happens this will probably be looked at by someone at Continuum this week, in response to a need on a client project, so you may be in luck soon. — bigreddot, Jul 12 '16 at 03:02
@bigreddot do you know if this is still happening? Highlighting lines in Bokeh would be a really cool feature. — jonalm, Mar 09 '17 at 20:47

score 16 · Accepted Answer · answered Mar 10 '17 at 00:06

16

As of Bokeh 0.12.4 (earlier, actually but I forget the exact release) the hover tool supports mutli_line:

from collections import defaultdict

import numpy as np
from scipy.stats import norm

from bokeh.plotting import show, figure
from bokeh.models import ColumnDataSource, HoverTool
from bokeh.palettes import Viridis6

RT_x = np.linspace(118, 123, num=50)

mass_spec = defaultdict(list)
for scale, mz in [(1.0, 83), (0.9, 55), (0.6, 98), (0.4, 43), (0.2, 39), (0.12, 29)]:
    mass_spec["RT"].append(RT_x)
    mass_spec["RT_intensity"].append(norm(loc=120.4).pdf(RT_x) * scale)
    mass_spec['MZ_tip'].append(mz)
    mass_spec['Intensity_tip'].append(scale)
mass_spec['color'] = Viridis6

source = ColumnDataSource(mass_spec)

p = figure(plot_height=400)
p.multi_line(xs='RT', ys='RT_intensity', legend="Intensity_tip",
             line_width=5, line_color='color', line_alpha=0.6,
             hover_line_color='color', hover_line_alpha=1.0,
             source=source)

p.add_tools(HoverTool(show_arrow=False, line_policy='next', tooltips=[
    ('MZ', '@MZ_tip'),
    ('Rel Intensity', '@Intensity_tip')
]))

show(p)

Which results in

answered Mar 10 '17 at 00:06

bigreddot

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Thanks. The reason I was confused was because I tried to use the `hover_line_alpha` keyword in the `MultiLine` model glyph, which gives `AttributeError: unexpected attribute 'hover_line_alpha' to MultiLine, ...` in 0.12.4. Is 'bokeh.plotting.figure' preferred over 'bokeh.models.Plot' (to be honest I don't really understand the difference)? – jonalm Mar 10 '17 at 08:57
Right, `hover_line_alpha` is a higher level convenience. Both `MultiLine` and `Plot` are low level building blocks. For example, `Plot` is basically just a container for things that can draw. You can put axes and grids into it, but *you* have to do it. `figure` is a higher level API, that puts a basic plot with axes and tools together for you. More info: http://bokeh.pydata.org/en/latest/docs/user_guide/concepts.html#interfaces – bigreddot Mar 10 '17 at 15:24
1

For anyone curious, if you want the x and y values added to your hover tool tip, you can use `$x` and `$y`. Full list of special, known fields: http://docs.bokeh.org/en/latest/docs/reference/models/tools.html#bokeh.models.tools.HoverTool.tooltips – Matt Popovich Dec 04 '20 at 08:43
Is this still working? I'm trying to replicate this and nothing is shown when I hover onto the plot. – Hojin Cho Mar 04 '21 at 01:50
1

There was a recent bug. It was fixed in latest 2.3 releases this week. – bigreddot Mar 04 '21 at 16:57

multi_line hover in bokeh

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