pyfragments

Add animations to revealjs presentations from Python code-blocks.

Example

A Revealjs presentation created with Quarto, which shows matplotlib figure animated with fragments (i.e., moving to the next slide):

This is created with the following code, in a Quarto .qmd file.

---
format: revealjs
---

## Animated scatterplot

Move to the next slide to see the transitions.

```{python}
# | output: asis
import matplotlib.pyplot as plt
from pyfragments.png import AnimatedFigure

with AnimatedFigure() as ani:
    plt.xlim(-1, 3)
    plt.ylim(-1, 3)
    for i in range(3):
        with ani.fragment():
            plt.scatter(i, i, s=200)

```

Docs

See the demo in GitHub Pages.

To change the order of fragments, or make different elements appear at the same time, use ani.fragment(<num>):

with ani.fragment(2):  # appears second
    ax.scatter(...)
with ani.fragment(1):  # appears first
    ax.scatter(...)
with ani.fragment(2):  # appears second
    ax.scatter(...)

SVG

To use SVG images, each call to a matplotlib function must include a group id (gid) with a value of .fragment.

---
format: revealjs
---

# Example of an animated figure

## Animated scatterplot

Move to the next slide to see the transitions.

```{python}
from matplotlib.figure import Figure
from pyfragments.svg import animate

fig = Figure()
ax = fig.add_subplot()
for i in range(3):
    ax.scatter(i, i, gid=".fragment")
animate(fig)
```

To change the order of fragments, or make different elements appear at the same time, use .fragment-<num>:

ax.scatter(..., gid=".fragment-2")  # appears second
ax.scatter(..., gid=".fragment-1")  # appears first
ax.scatter(..., gid=".fragment-2")  # appears second

To allow animation of images, such as with ax.imshow, it is important to disable image.composite_image:

import matplotlib

matplotlib.rc("image", composite_image=False)

Install

Using pixi, install from PyPI with:

pixi add --pypi pyfragments

or install the latest development version from GitHub with:

pixi add --pypi pyfragments@https://github.com/maurosilber/pyfragments.git

Otherwise, use pip or your pip-compatible package manager:

pip install pyfragments  # from PyPI
pip install git+https://github.com/maurosilber/pyfragments.git  # from GitHub

Development

This project is managed by pixi. You can install it for development using:

git clone https://github.com/maurosilber/pyfragments
cd pyfragments
pixi run pre-commit-install

Pre-commit hooks are used to lint and format the project.

Testing

Run tests using:

pixi run test

Publishing to PyPI

When a tagged commit is pushed to GitHub, the GitHub Action defined in .github/workflows/ci.yml builds and publishes the package to PyPI.

Tag a commit and push the tags with:

git tag <my-tag>
git push --tags

Trusted publishing must be enabled once in PyPI Publishing. Fill the following values in the form:

PyPI Project Name: pyfragments
            Owner: maurosilber
  Repository name: pyfragments
    Workflow name: ci.yml
 Environment name: pypi