altair-viewer 0.1.0

A background data server for Altair charts.

Altair Viewer

Offline chart viewer for Altair visualizations

This package provides tools for viewing Altair charts without a web connection in arbitrary Python environments. Charts can be displayed either inline in a Jupyter notebook environment, or in a separate browser window for use in any environment.

Installation

The development version of Altair-viewer can be installed with pip:

$ pip install git+http://github.com/altair-viz/altair_viewer.git

Usage: General Environments

Altair viewer provides two top-level functions for displaying charts: altair_viewer.display() and altair_viewer.show(). Their use is slightly different:

• altair_viewer.display(chart) is meant for use in interactive computing environments where a single Python process is used interactively. It will serve a chart viewer at a localhost URL, and any susequent chart created within the session will appear in the same window. The background server will be terminated when the main Python process terminates, so this is not suitable for standalone scripts.

• altair_viewer.show(chart) is meant for use once at the end of a script. It does the same as display(), but automatically opens a browser window, and adds an input prompt to prevent the script (and the server it creates) from terminating.

Usage: IPython & Jupyter

Within Jupyter notebook, IPython notebook, and related environments that support Mimetype-based display, altair viewer can be used by enabling the altair_viewer renderer:

import altair as alt
alt.renderers.enable('altair_viewer')

This will cause charts at the end of a Jupyter notebook cell to be rendered in a separate browser window, as with the display() and show() methods.

If enabled with inline=True, charts will be rendered inline in the notebook:

import altair as alt
alt.renderers.enable('altair_viewer', inline=True)

To display a single chart using Altair viewer in an IPython environment without globally enabling the associated renderer, you can use the display method:

import altair_viewer
altair_viewer.display(chart, inline=True)

Note that the display based on altair viewer will only function correctly as long as the Kernel that created the charts is active, as it depends on the background server started by the kernel. In particular, this means that if you save a notebook and reopen it later, charts will not display until the associated cells are re-run.