overlayng/MaximalEdgeRing.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************/
 
#pragma once
 
#include <geos/operation/overlayng/OverlayEdgeRing.h>
 
#include <vector>
#include <memory>
#include <geos/export.h>
 
// Forward declarations
namespace geos {
namespace geom {
class Coordinate;
class CoordinateArray;
class GeometryFactory;
}
namespace operation {
namespace overlayng {
class OverlayEdge;
class EdgeRing;
}
}
}
 
namespace geos {      // geos.
namespace operation { // geos.operation
namespace overlayng { // geos.operation.overlayng
 
using namespace geos::geom;
 
class GEOS_DLL MaximalEdgeRing {
 
private:
 
    // Constants
    static constexpr int STATE_FIND_INCOMING = 1;
    static constexpr int STATE_LINK_OUTGOING = 2;
 
    // Members
    OverlayEdge* startEdge;
 
    // Methods
    void attachEdges(OverlayEdge* startEdge);
    void linkMinimalRings();
 
    static void linkMinRingEdgesAtNode(OverlayEdge* nodeEdge, MaximalEdgeRing* maxRing);
 
    static bool isAlreadyLinked(OverlayEdge* edge, MaximalEdgeRing* maxRing);
 
    static OverlayEdge* selectMaxOutEdge(OverlayEdge* currOut, MaximalEdgeRing* maxEdgeRing);
    static OverlayEdge* linkMaxInEdge(OverlayEdge* currOut, OverlayEdge* currMaxRingOut, MaximalEdgeRing* maxEdgeRing);
 
 
public:
 
    MaximalEdgeRing(OverlayEdge* e)
        : startEdge(e)
    {
        attachEdges(e);
    };
 
    std::vector<std::unique_ptr<OverlayEdgeRing>> buildMinimalRings(const GeometryFactory* geometryFactory);
 
    static void linkResultAreaMaxRingAtNode(OverlayEdge* nodeEdge);
 
    friend std::ostream& operator<<(std::ostream& os, const MaximalEdgeRing& mer);
 
};
 
 
} // namespace geos.operation.overlayng
} // namespace geos.operation
} // namespace geos