import panel as pn
import numpy as np
import holoviews as hv
pn.extension(sizing_mode = 'stretch_width')
For a large variety of use cases we do not need complete control over the exact layout of each individual component on the page, as could be achieved with a custom template, we just want to achieve a more polished look and feel. For these cases Panel ships with a number of default templates, which are defined by declaring four main content areas on the page, which can be populated as desired:
header: The header area of the HTML pagesidebar: A collapsible sidebarmain: The main area of the applicationmodal: A modal area which can be opened and closed from Python
These four areas behave very similarly to other Panel layout components and have list-like semantics. This means we can easily append new components into these areas. Unlike other layout components however, the contents of the areas is fixed once rendered. If you need a dynamic layout you should therefore insert a regular Panel layout component (e.g. a Column or Row) and modify it in place once added to one of the content areas.
Templates can allow for us to quickly and easily create web apps for displaying our data. Panel comes with a default Template, and includes multiple Templates that extend the default which add some customization for a better display.
Parameters:¶
In addition to the four different areas we can populate the default templates also provide a few additional parameters:
busy_indicator(BooleanIndicator): Visual indicator of application busy state.header_background(str): Optional header background color override.header_color(str): Optional header text color override.logo(str): URI of logo to add to the header (if local file, logo is base64 encoded as URI).site(str): Name of the site. Will be shown in the header. Default is '', i.e. not shown.site_url(str): Url of the site and logo. Default is "/".title(str): A title to show in the header.theme(Theme): A Theme class (available inpanel.template.theme)sidebar_width(int): The width of the sidebar in pixels. Default is 370.
In this case we are using the MaterialTemplate, built on Material Components for the web, which is a CSS framework that provides a lot of built in stylings to create a smooth layout. Here is an example of how you can set up a display using this template:
material = pn.template.MaterialTemplate(title='Material Template')
xs = np.linspace(0, np.pi)
freq = pn.widgets.FloatSlider(name="Frequency", start=0, end=10, value=2)
phase = pn.widgets.FloatSlider(name="Phase", start=0, end=np.pi)
@pn.depends(freq=freq, phase=phase)
def sine(freq, phase):
return hv.Curve((xs, np.sin(xs*freq+phase))).opts(
responsive=True, min_height=400)
@pn.depends(freq=freq, phase=phase)
def cosine(freq, phase):
return hv.Curve((xs, np.cos(xs*freq+phase))).opts(
responsive=True, min_height=400)
material.sidebar.append(freq)
material.sidebar.append(phase)
material.main.append(
pn.Row(
pn.Card(hv.DynamicMap(sine), title='Sine'),
pn.Card(hv.DynamicMap(cosine), title='Cosine')
)
)
material.servable();
MaterialTemplate with DefaultTheme
MaterialTemplate with DarkTheme
The app can be displayed within the notebook by using .servable(), or rendered in another tab by replacing it with .show().
Themes can be added using the optional keyword argument theme. Each template comes with a DarkTheme and a DefaultTheme, which can be set MaterialTemplate(theme=DarkTheme). If no theme is set, then DefaultTheme will be applied.
It should be noted that Templates may not render correctly in a notebook, and for the best performance they should ideally be deployed to a server.