Aleph::PointInPolygonWinding Class Reference

Exact point-in-polygon classification via winding number. More...

#include <geom_algorithms.H>

Public Types
enum class	Location { Outside , Boundary , Inside }

Static Public Member Functions
static Location	locate (const Polygon &poly, const Point &p)
	Classify point location with respect to a polygon.
static bool	contains (const Polygon &poly, const Point &p)
	Return true if the point is inside or on the boundary.
static bool	strictly_contains (const Polygon &poly, const Point &p)
	Return true only for strict interior points.

Detailed Description

Exact point-in-polygon classification via winding number.

Classifies a point relative to a simple closed polygon as:

• Inside
• Boundary
• Outside

Uses exact geometric predicates (orientation, on_segment) with Geom_Number, avoiding floating-point robustness issues.

Requirements

• Polygon must be closed.
• Polygon must have at least 3 vertices.
• Polygon should be simple (non-self-intersecting).

Complexity

• Time: O(n), where n is number of polygon edges.
• Space: O(1).

Definition at line 1489 of file geom_algorithms.H.

Member Enumeration Documentation

Location

enum class Aleph::PointInPolygonWinding::Location

strong

Enumerator
Outside
Boundary
Inside

Definition at line 1492 of file geom_algorithms.H.

Member Function Documentation

contains()

static bool Aleph::PointInPolygonWinding::contains ( const Polygon &  poly, const Point &  p  )

inlinestatic

Return true if the point is inside or on the boundary.

Parameters

poly	Closed simple polygon.
p	Query point.

Returns

true iff location is Inside or Boundary.

Definition at line 1533 of file geom_algorithms.H.

References locate(), and Outside.

Referenced by brute_convex_distance_squared(), demo_advanced_algorithms(), Aleph::ShortestPathInPolygon::operator()(), Aleph::ConvexPolygonDistanceGJK::polygons_intersect_or_contain(), Aleph::detail::shortest_path_portals(), and TEST_F().

locate()

static Location Aleph::PointInPolygonWinding::locate ( const Polygon &  poly, const Point &  p  )

inlinestatic

Classify point location with respect to a polygon.

Parameters

poly	Closed simple polygon.
p	Query point.

Returns

Location::Outside, Location::Boundary, or Location::Inside.

Exceptions

domain_error

if polygon is open or has fewer than 3 vertices.

Definition at line 1508 of file geom_algorithms.H.

References ah_domain_error_if, Boundary, Aleph::Polygon::Boundary, Aleph::divide_and_conquer_partition_dp(), Inside, Aleph::Polygon::Inside, Aleph::Polygon::is_closed(), Aleph::Polygon::locate_point(), Outside, Aleph::Polygon::Outside, and Aleph::Polygon::size().

Referenced by contains(), strictly_contains(), TEST(), and TEST_F().

strictly_contains()

static bool Aleph::PointInPolygonWinding::strictly_contains ( const Polygon &  poly, const Point &  p  )

inlinestatic

Return true only for strict interior points.

Parameters

poly	Closed simple polygon.
p	Query point.

Returns

true iff location is Inside.

Definition at line 1546 of file geom_algorithms.H.

References Inside, and locate().

Referenced by Aleph::VisibilityPolygon::operator()().

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The documentation for this class was generated from the following file:

• geom_algorithms.H