SVG Primitives

Build mm-precise SVG schematics in Python with three mechanical guarantees:

1. Text never overflows its container — labeled shapes auto-size to fit measured text bbox + padding.
2. Arrowheads stay tangent-correct — arrows emit <marker orient="auto"> so the renderer rotates the head along the path's terminal tangent; works on straight lines and cubic Beziers.
3. Paint order is deterministic — layers paint in registration order; connectors visibly pass under boxes without manual reordering.

The skill ships an end-to-end pytest suite (50+ tests) that renders SVGs and asserts these invariants on the rendered output, so the guarantees are enforced by construction rather than by hand-checking each figure.

When to use this skill

Reach for svg-primitives when:

• The figure is a schematic (boxes, arrows, labels) and you're driving it from Python — e.g. nodes come from a YAML config, or the layout depends on data.
• You need the boxes to auto-fit their labels (no hand-tuning widths).
• The figure has curved arrows that must point cleanly at their targets.
• You want deterministic z-order so connectors sit under shapes without manual element reordering.
• The output will be composed into a multi-panel figure as a panel SVG that scientific-figure/compose.py loads.