Minimal call
c = pt.chart(xlim=(0, 5), ylim=(0, 3.5))
c.add_polygon([0, 2, 1], [0, 0, 2], alpha=0.5)
c.add_polygon([3, 4, 3, 2], [1, 2, 3, 2], fill="none", linewidth=2)
Docstring
User-supplied geometry primitives — rect, polygon, polyline.
`rect` is scale-aware and broadcasts hlines/vlines-style. `polygon` takes
a single closed contour from parallel `xs` / `ys` vertices. `polyline` is
the open-path counterpart to `polygon` — same `(xs, ys)` shape, stroke-only,
never closes. Use it for diagonal reference segments and decorative
multi-point paths in data coords (the gap between `hlines`/`vlines` and
the data-shaped `c.add_line(aes(...))`).