Altair Saver - Playwright

Note You should use vl-convert instead of this, as it requires no additional dependencies and is pip installable. It will become the default export engine in Altair 5 as well.

Installing the requirements for altair_saver correctly is annoying. This library makes it much easier if you want png or svg output for altair plots.

Install

pip install git+https://github.com/pmbaumgartner/altair-saver-playwright
playwright install chromium

Don't forget that second step to install chromium!

Use

from altair_saver_playwright import save

import altair as alt
import pandas as pd

source = pd.DataFrame(
    {
        "a": ["A", "B", "C", "D", "E", "F", "G", "H", "I"],
        "b": [28, 55, 43, 91, 81, 53, 19, 87, 52],
    }
)

chart = alt.Chart(source).mark_bar().encode(x="a", y="b")

save(chart, "mycoolchart.svg")

In a notebook? Use the async API. (Related info)

from altair_saver_playwright import save_async  # Note new function name here

import altair as alt
import pandas as pd

source = pd.DataFrame(
    {
        "a": ["A", "B", "C", "D", "E", "F", "G", "H", "I"],
        "b": [28, 55, 43, 91, 81, 53, 19, 87, 52],
    }
)

chart = alt.Chart(source).mark_bar().encode(x="a", y="b")

# Don't forget the await here
await save_async(chart, "mycoolchart.svg")

What is this doing?

This package:

• Saves the chart as HTML (which is built into altair) in a temporary file
• Uses chromium installed via playwright (much easier install) to navigate to the saved HTML
• Clicks the Menu in the HTML file to "Save to PNG/SVG"
• Saves the download to the path you determine