Loading Indicator

import time
import panel as pn
import holoviews as hv
import numpy as np
import holoviews.plotting.bokeh

pn.extension(loading_spinner='dots', loading_color='#00aa41', template='bootstrap')
hv.extension('bokeh')

Every pane, widget and layout provides the loading parameter. When set to True a spinner will overlay the panel and indicate that the panel is currently loading. When you set loading to false the spinner is removed.

Using the pn.extension or by setting the equivalent parameters on pn.config we can select between different visual styles and colors for the loading indicator.

pn.extension(loading_spinner='dots', loading_color='#00aa41')

We can enable the loading indicator for reactive functions annotated with depends or bind globally using:

pn.param.ParamMethod.loading_indicator = True

Alternatively we can enable it for a specific function by passing the loading_indicator=True argument to pn.panel or directly to the underlying ParamMethod/ParamFunction object:

button = pn.widgets.Button(name="UPDATE", button_type="primary", sizing_mode='stretch_width')

def random_plot(event):
    if event: time.sleep(5)
    return hv.Points(np.random.rand(100, 2)).opts(
        responsive=True, height=400, size=8, color="green")

pn.Column(
    button,
    pn.param.ParamFunction(pn.bind(random_plot, button), loading_indicator=True)
).servable()