Public Member Functions | Protected Member Functions | Protected Attributes

geos::geom::prep::AbstractPreparedPolygonContains Class Reference

A base class containing the logic for computes the contains and covers spatial relationship predicates for a PreparedPolygon relative to all other Geometry classes. More...

#include <AbstractPreparedPolygonContains.h>

Inheritance diagram for geos::geom::prep::AbstractPreparedPolygonContains:
geos::geom::prep::PreparedPolygonPredicate geos::geom::prep::PreparedPolygonContains geos::geom::prep::PreparedPolygonCovers

List of all members.

Public Member Functions

 AbstractPreparedPolygonContains (const PreparedPolygon *const prepPoly)
 AbstractPreparedPolygonContains (const PreparedPolygon *const prepPoly, bool requireSomePointInInterior)

Protected Member Functions

bool eval (const geom::Geometry *geom)
virtual bool fullTopologicalPredicate (const geom::Geometry *geom)=0

Protected Attributes

bool requireSomePointInInterior

Detailed Description

A base class containing the logic for computes the contains and covers spatial relationship predicates for a PreparedPolygon relative to all other Geometry classes.

Uses short-circuit tests and indexing to improve performance.

Contains and covers are very similar, and differ only in how certain cases along the boundary are handled. These cases require full topological evaluation to handle, so all the code in this class is common to both predicates.

It is not possible to short-circuit in all cases, in particular in the case where line segments of the test geometry touches the polygon linework. In this case full topology must be computed. (However, if the test geometry consists of only points, this can be evaluated in an optimized fashion.

Author:
Martin Davis

Member Function Documentation

bool geos::geom::prep::AbstractPreparedPolygonContains::eval ( const geom::Geometry geom  )  [protected]

Evaluate the contains or covers relationship for the given geometry.

Parameters:
geom the test geometry
Returns:
true if the test geometry is contained

Referenced by geos::geom::prep::PreparedPolygonContains::contains(), and geos::geom::prep::PreparedPolygonCovers::covers().

virtual bool geos::geom::prep::AbstractPreparedPolygonContains::fullTopologicalPredicate ( const geom::Geometry geom  )  [protected, pure virtual]

Computes the full topological predicate. Used when short-circuit tests are not conclusive.

Parameters:
geom the test geometry
Returns:
true if this prepared polygon has the relationship with the test geometry

Implemented in geos::geom::prep::PreparedPolygonContains, and geos::geom::prep::PreparedPolygonCovers.


Member Data Documentation

This flag controls a difference between contains and covers.

For contains the value is true. For covers the value is false.


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