Minimal call
c = pt.chart(xlim=(0, 8), ylim=(0, 4))
c.add_rect([0, 2, 4, 6], 0, 1.5, 2, fill="C0", alpha=0.6)
c.add_rect(0.5, 2.5, 7, 1, fill="C1", alpha=0.3)
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(...))`).