feat: Shape.contains / Shape.boundary for source-plane shapes (image-source-mappings P2a)

[Jammy2211]

Summary

Phase 2a of the image-source-mappings epic: point containment and boundary polygons for the source-plane Shape classes, plus three defects the Phase 2 ShapeSolver validation suite exposed in PyAutoArray's triangle and overlay code. This is the PyAutoArray half of PyAutoLabs/PyAutoLens#719; the PyAutoLens PR (PyAutoLabs/PyAutoLens#720) depends on it — its CI is source-installed against PyAutoArray main, so it goes green once this merges. Merge order: this PR first.

• Shape.contains(points) -> bool array on every shape: Circle radial, Triangle barycentric, Polygon any-of its fan triangles (exact for convex polygons), Square bounds; Point.contains raises, pointing at Circle / PointSolver.
• Shape.boundary(n=100) -> (n, 2) closed loop for drawing the source-plane region.
• The coordinate convention is documented once on the Shape base class: points use the same axis order as triangles[..., 0] / [..., 1] that mask() already reads, and PointSolver.solve builds Point(*source_plane_coordinate) from a (y, x) tuple, so the attribute named x holds the first (y) coordinate.

Audit findings (all fixed here, each with a regression test)

Finding	Commit	Evidence
Triangle.triangle_contains_mask tested the reflected triangle: it unpacked vertices as y1, x1 = self.a (element 1 as "x") while testing a centroid built as (element 0, element 1). On the asymmetric triangle ((0,0),(3,0),(0,1)) the interior point (2.0, 0.2) read as outside and its reflection (0.2, 2.0) as inside. Every symmetric shape in the existing test_polygons.py hid it. All three barycentric copies now share one _barycentric_contains helper.	b1f88f4a	test_shape.py::test_triangle_contains_mask_is_not_reflected; ::test_contains_uses_the_same_axis_order_as_the_triangle_array pins the convention empirically
CoordinateArrayTriangles{,Np}.for_limits_and_scale named its first pair of limits x_min/x_max and tiled them along element 0, while element 0 is y everywhere else (ArrayTrianglesNp, every (y, x) grid, the Shape convention). Both the keyword caller (AbstractSolver._initial_triangles) and the positional caller (AbstractTriangles.for_grid) tiled the transposed rectangle. Invisible on a square grid; on a 24×80 grid of 0.05" pixels PointSolver.solve found one of an Isothermal's two images instead of both, the missing one well inside the grid.	67b1cb75	test_coordinate.py::test_for_limits_and_scale__element_0_spans_the_y_limits, ::test_for_grid__rectangular_grid_is_tiled_the_same_way_round
Stray bbbb statement in ArrayTrianglesNp.with_vertices — a NameError on every call since 2025-11, unreached because the solver only uses the CoordinateArrayTrianglesNp override.	67b1cb75	test_coordinate.py::test_array_triangles_with_vertices_returns_new_triangles
plot_regions drew one label per region entry at the mean of all its polygons, so a mapping's label for two multiple images landed on empty sky between them. Multi-polygon regions now carry the label once per polygon.	a9a9120a	new tests in test_autoarray/plot/ (a two-polygon region with one label yields two text artists)

Square.mask / Square.area assume top < bottom numerically, consistent with their "coordinates from the top-left corner" docstring — not a bug. The new contains / boundary sort the bounds so they also work for arcsec (y, x) squares (test_shape.py::test_square_contains_is_robust_to_coordinate_ordering).

API Changes

• Added Shape.contains(points) and Shape.boundary(n=100) (abstract on Shape; implemented on Point, Circle, Triangle, Polygon, Square).
• Changed CoordinateArrayTriangles.for_limits_and_scale / CoordinateArrayTrianglesNp.for_limits_and_scale signature order from (x_min, x_max, y_min, y_max, scale) to (y_min, y_max, x_min, x_max, scale), matching the abstract base and the positional caller. Keyword callers are unaffected by the reorder and now get the rectangle they asked for. Behaviour change: PointSolver on a non-square grid now searches the grid's actual extent and can return multiple images it previously missed.
• Changed plot_regions label placement for multi-polygon regions (one label per polygon).
• mask(triangles), area, the pytree methods and autoarray/__init__.py are untouched.

Tests

• New test_autoarray/structures/triangles/test_shape.py (19 tests) and additions to test_coordinate.py (3) and test_autoarray/plot/ (2).
• pytest test_autoarray -q: 1410 passed (Phase 1 shipped at 1382).

Epic

image-source-mappings phase 2a — ledger PyAutoMind/draft/feature/autoarray/image_source_mappings_epic.md. Phase 1 was PyAutoArray#517. Label pending-release.

🤖 Generated with Claude Code

https://claude.ai/code/session_011EVnQ4sEYrRM7GCvFyveUA