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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 page

  • sidebar: A collapsible sidebar

  • main: The main area of the application

  • modal: 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.


In addition to the four different areas we can populate, the FastListTemplate also provides the parameters below:

  • 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 “/”.

  • logo (str): URI of logo to add to the header (if local file, logo is base64 encoded as URI).

  • title (str): A title to show in the header. Also added to the document head meta settings and as the browser tab title.

  • favicon (str): URI of favicon to add to the document head (if local file, favicon is base64 encoded as URI).

  • sidebar_footer (str): Can be used to insert additional HTML. For example a menu, some additional info, links etc.

  • config (TemplateConfig): Contains configuration options similar to pn.config but applied to the current Template only. (Currently only css_files is supported)

  • busy_indicator (BooleanIndicator): Visual indicator of application busy state.

For styling you can use

  • theme (Theme): A Theme class (available in panel.template. One of DefaultTheme or DarkTheme).

    • For convenience you can provide “default” or “dark” string to the constructor.

    • If you add ?theme=default or ?theme=dark in the url this will set the theme unless explicitly declared

  • theme_toggle (boolean): If True a switch to toggle the Theme is shown. Default is True.

  • background_color (str): Optional body background color override.

  • neutral_color (str): Optional body neutral color override.

  • accent_base_color (str): Optional body accent base color override. The default is #0072B5 (French Blue).

  • header_background (str): Optional header background color override.

  • header_color (str): Optional header text color override.

  • header_neutral_color (str): Optional header neutral color override.

  • header_accent_base_color (str): Optional header accent base color override.

  • corner_radius (str): The corner radius applied to controls.

  • font (str): A font url to import.

  • font_url (str): A font url to import.

  • shadow (str): Optional shadow override. Whether or not to apply shadow.

  • main_layout (str): What to wrap the main components into. Options are ‘’ (i.e. none) and ‘card’ (Default). Could be extended to Accordion, Tab etc. in the future.

The accent argument is a short cut to set both the accent_base_color and the header_background. Some accent colors that work well are #A01346 (Fast), #00A170 (Mint), #DAA520 (Golden Rod), #2F4F4F (Dark Slate Grey), #F08080 (Light Coral) and #4099da (Summer Sky).

For layout you can use

  • sidebar_width (int): The width of the sidebar in pixels. Default is 330.

  • main_max_width (str): The maximum width of the main area. For example ‘800px’ or ‘80%’. If the string is ‘’ (default) no max width is set.

For meta and base values you can use

  • meta_description (str): A meta description to add to the document head for search engine optimization. For example ‘P.A. Nelson’.

  • meta_keywords (str): Meta keywords to add to the document head for search engine optimization.

  • meta_author (str): A meta author to add to the the document head for search engine optimization. For example ‘P.A. Nelson’.

  • meta_refresh (str): A meta refresh rate to add to the document head. For example ‘30’ will instruct the browser to refresh every 30 seconds. Default is ‘’, i.e. no automatic refresh.

  • meta_viewport (str): A meta viewport to add to the header.

  • base_url (str): Specifies the base URL for all relative URLs in a page. Default is ‘’, i.e. not the domain.

  • base_target (str): Specifies the base Target for all relative URLs in a page. Default is _self.

In this case we are using the FastListTemplate, built using the Fast.design framework. Here is an example of how you can set up a display using this template:

ACCENT_COLOR = pn.template.FastListTemplate.accent_base_color
XS = np.linspace(0, np.pi)

def sine(freq, phase):
    return hv.Curve((XS, np.sin(XS * freq + phase))).opts(
        responsive=True, min_height=400, title="Sine", color=ACCENT_COLOR

def cosine(freq, phase):
    return hv.Curve((XS, np.cos(XS * freq + phase))).opts(
        responsive=True, min_height=400, title="Cosine", color=ACCENT_COLOR

freq = pn.widgets.FloatSlider(name="Frequency", start=0, end=10, value=2)
phase = pn.widgets.FloatSlider(name="Phase", start=0, end=np.pi)

sine = pn.bind(sine, freq=freq, phase=phase)
cosine = pn.bind(cosine, freq=freq, phase=phase)

template = pn.template.FastListTemplate(
    site="Panel", title="FastListTemplate",
    sidebar=[pn.pane.Markdown("## Settings"), freq, phase],
    main=[pn.pane.HoloViews(hv.DynamicMap(sine) + hv.DynamicMap(cosine), sizing_mode="stretch_both")]

FastListTemplate with DefaultTheme

FastListTemplate 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. This template comes with a DarkTheme and a DefaultTheme, which can be set via FastlistTemplate(theme="dark"). If no theme is set, then DefaultTheme will be applied.

It should be noted this template currently does not render correctly in a notebook, and for the best performance the should ideally be deployed to a server.

This web page was generated from a Jupyter notebook and not all interactivity will work on this website. Right click to download and run locally for full Python-backed interactivity.

Download this notebook from GitHub (right-click to download).