feat: support Vega-Lite charting library #540
Description
Summary
Add support for Vega-Lite as a third-party charting library that maidr can work with.
Background
Vega-Lite is a high-level declarative grammar of interactive graphics, widely used in academic research, data science notebooks, and tools like Observable, Altair (Python), and Jupyter. It renders charts as SVG. chart2music provides a Vega-Lite integration example.
What This Involves
- Binder/Adapter: Create an adapter that extracts the Vega-Lite specification (JSON) and compiled data to generate the MAIDR JSON schema. Vega-Lite specs are declarative and data-rich, making extraction relatively straightforward.
- SVG Highlighting: Vega-Lite renders standard SVG elements. CSS selectors can target mark elements for highlighting.
- Chart Types: Vega-Lite supports bar, line, area, point (scatter), rect (heatmap), boxplot, tick, circle, square, rule, text, and composite views (layered, faceted, concatenated).
Considerations
- Vega-Lite's declarative spec contains all the data and encoding information needed to generate the MAIDR schema, potentially making this one of the most straightforward integrations.
- Vega-Lite supports composite views (layered, faceted, concatenated), which maps well to maidr's multi-layer and multi-panel support.
- The Vega ecosystem includes Vega-Embed for rendering — the adapter could hook into the view instance.
- Strong overlap with academic/research use cases where accessibility is especially important.
Reference
- chart2music Vega-Lite example: https://codepen.io/chart2music/full/jOzpyME
- Vega-Lite: https://vega.github.io/vega-lite/
- Altair (Python Vega-Lite): https://altair-viz.github.io/