Holoviews plot with horizontal scrollbar?

Question

I would like to realize a holoviews plot with a scrollbar for the time/x axis.

In detail, I want to plot a long ecg signal (20 minutes) and be able to display a frame of e.g. 10 seconds with the possibility to scroll along the entire signal.

Is there a way to realize this? Thank you!

Example

Answer 1

There are at least two options you should know about.

1. Option

Enable the scrolling by mouse. For this you have to activate the tool xwheel_pan for your figure.

See this very basic example:

import numpy as np
import holoviews as hv
hv.extension('bokeh')

x = np.linspace(0, 4*np.pi, 100)
y = np.sin(x)
scatter = hv.Scatter((x, y), label='sin(x)').opts(
        tools=['xwheel_pan'], 
        active_tools=['xwheel_pan']
    )
scatter

In this example the tool is also activated by default. Using the wheel of the mouse will result in an action like this.

2. Option

Add a second figure and a RangeTool.

This example needs some more lines of code:

import numpy as np
import holoviews as hv
from holoviews import opts
from holoviews.plotting.links import RangeToolLink
hv.extension('bokeh')

x = np.linspace(0, 4*np.pi, 100)
y = np.sin(x)
scatter = hv.Scatter((x, y), label='sin(x)').opts(width=300, height=300)
selection = hv.Scatter((x, y)).opts(width=300, height=100, yaxis=None, default_tools=[])

RangeToolLink(selection, scatter)
layout = (scatter + selection).cols(1)
layout.opts(opts.Layout(shared_axes=False, merge_tools=False))