Crate geometry_overlay 

Boolean-overlay engine — the segment-intersection kernel and the machinery built on top of it.

Mirrors boost/geometry/algorithms/detail/overlay/. Overlay is the engine behind intersection, union, difference, sym_difference, and (indirectly) buffer, is_valid, relate, crosses, overlaps, touches, point_on_surface, and merge_elements. Boost concentrates all of it under one detail directory; the port gives it its own crate because the algorithmic surface is too dense to share a crate with anything else.

The build order is strict:

• predicate — OVL1: the robust predicate layer every overlay operation eventually calls (orientation, in-circle, segment-segment intersection, coordinate-range gate).
• turn graph → traversal → output assembly → the four overlay free functions land in later phases, each behind the same strict ordering.

Robustness

v1 uses exact input arithmetic with no rescale — the predicates compute directly on the f64 inputs and the predicate::range_guard refuses inputs outside the safe arithmetic range rather than silently returning a wrong sign, leaving a slot for a future rescale policy.

Re-exports

pub use buffer::JoinStrategy;

pub use buffer::PointStrategy;

pub use buffer::buffer_convex_polygon;

pub use buffer::buffer_point;

pub use merge::merge_multipolygon;

pub use merge::merge_polygons;

pub use operation::OverlayError;

pub use operation::difference;

pub use operation::intersection;

pub use operation::sym_difference;

pub use operation::union_poly;

pub use relate::De9im;

pub use relate::Dimension;

pub use relate::crosses;

pub use relate::overlaps;

pub use relate::relate as relate_matrix;

pub use relate::touches;

pub use surface_point::point_on_surface;

pub use validity::ValidityFailure;

pub use validity::is_valid_polygon;

pub use validity::is_valid_ring;

Modules

assemble

OVL4 — output assembly: turn traversed rings into a MultiPolygon.

buffer

OVL7 — buffer: grow a geometry outward by a fixed distance.

merge

OVL8 — merge_elements: combine overlapping polygons via union.

operation

OVL5 — the boolean overlay free functions.

predicate

OVL1 — the robust predicate layer.

relate

OVL6.T1 / OVL6.T2 — the DE-9IM relate matrix and the spatial predicates derived from it.

surface_point

OVL6.T3 — point_on_surface.

traverse

OVL3 — traversal: walk the turn graph to assemble output rings.

turn

OVL2 — the turn graph.

validity

OVL6.T4 — is_valid for rings and polygons.