matplotlib-lossless-webp

A tiny Python package that forces lossless compression in matplotlib when saving WebP images.

Otherwise, matplotlib's .webp exports are somewhat low quality unless you set specific PIL parameters.

In this way, you can use .webp as a smaller, drop-in replacement for .png while maintaining perfect quality.

Installation

This project is on PyPI and can be installed with

pip install matplotlib-lossless-webp

Usage

Importing the package will force all future savefig() calls to be lossless when the filename ends with .webp.

import matplotlib.pyplot as plt
import matplotlib_lossless_webp  # noqa

plt.plot([1, 2, 3], [4, 5, 6])
plt.savefig('test.webp')  # automatically saves as lossless / high quality

Why?

This is mostly for convenience, but scientific figures should normally be lossless, so this is a reasonable default!

Matplotlib is a bit strange for .webp files in that you can't just pass something like savefig(..., quality=100) or savefig(..., lossless=True).

The (allegedly) intended invocation is to pass the lossless parameter through to PIL with savefig(..., pil_kwargs={'lossless': True}), but that is cumbersome to add repeatedly.

If this needs to be disabled on a rare, case-by-case basis, this package will not override explicit usage like savefig(..., pil_kwargs={'lossless': False}).