oppolygonize.h

一个很好的vc代码

	/*
	 * \brief
	 * Computes the EdgeRings formed by the edges in this graph.
	 *
	 * @return a list of the EdgeRing found by the
	 * 	polygonization process.
	 */
	vector<polygonizeEdgeRing*>* getEdgeRings();

	/*
	 * \brief
	 * Finds and removes all cut edges from the graph.
	 *
	 * @return a list of the LineString forming the removed cut edges
	 */
	vector<const LineString*>* deleteCutEdges();

	/*
	 * Marks all edges from the graph which are "dangles".
	 * Dangles are which are incident on a node with degree 1.
	 * This process is recursive, since removing a dangling edge
	 * may result in another edge becoming a dangle.
	 * In order to handle large recursion depths efficiently,
	 * an explicit recursion stack is used
	 *
	 * @return a List containing the LineStrings that formed dangles
	 */
	vector<const LineString*>* deleteDangles();

private:
	static int getDegreeNonDeleted(planarNode *node);
	static int getDegree(planarNode *node, long label);
	const GeometryFactory *factory;
	planarNode* getNode(const Coordinate& pt);
	void computeNextCWEdges();

	/*
	 * \brief
	 * Convert the maximal edge rings found by the initial graph traversal
	 * into the minimal edge rings required by JTS polygon topology rules.
	 *
	 * @param ringEdges
	 * 	the list of start edges for the edgeRings to convert.
	 */
	void convertMaximalToMinimalEdgeRings(vector<PolygonizeDirectedEdge*> *ringEdges);

	/*
	 * \brief
	 * Finds all nodes in a maximal edgering which are self-intersection
	 * nodes
	 *
	 * @param startDE
	 * @param label
	 * @return the list of intersection nodes found,
	 * or <code>null</code> if no intersection nodes were found.
	 * Ownership of returned vector goes to caller.
	 */
	static vector<planarNode*>* findIntersectionNodes(PolygonizeDirectedEdge *startDE, long label);

	/*
	 * @param dirEdges a List of the DirectedEdges in the graph
	 * @return a List of DirectedEdges, one for each edge ring found
	 */
	static vector<PolygonizeDirectedEdge*>* findLabeledEdgeRings(vector<planarDirectedEdge*> *dirEdges);

	static void label(vector<planarDirectedEdge*> *dirEdges, long label);

	static void computeNextCWEdges(planarNode *node);

	/**
	 * \brief
	 * Computes the next edge pointers going CCW around the given node,
	 * for the given edgering label.
	 * This algorithm has the effect of converting maximal edgerings
	 * into minimal edgerings
	 */
	static void computeNextCCWEdges(planarNode *node, long label);

	/**
	 * \brief
	 * Traverse a ring of DirectedEdges, accumulating them into a list.
	 * This assumes that all dangling directed edges have been removed
	 * from the graph, so that there is always a next dirEdge.
	 *
	 * @param startDE the DirectedEdge to start traversing at
	 * @return a List of DirectedEdges that form a ring
	 */
	static vector<planarDirectedEdge*>* findDirEdgesInRing(PolygonizeDirectedEdge *startDE);

	polygonizeEdgeRing* findEdgeRing(PolygonizeDirectedEdge *startDE);

	/* Tese are for memory management */
	vector<planarEdge *>newEdges;
	vector<planarDirectedEdge *>newDirEdges;
	vector<planarNode *>newNodes;
	vector<polygonizeEdgeRing *>newEdgeRings;
	vector<CoordinateSequence *>newCoords;
};

/*
 * Polygonizes a set of Geometrys which contain linework that
 * represents the edges of a planar graph.
 * Any dimension of Geometry is handled - the constituent linework is extracted
 * to form the edges.
 * The edges must be correctly noded; that is, they must only meet
 * at their endpoints.  The Polygonizer will still run on incorrectly noded input
 * but will not form polygons from incorrected noded edges.
 * <p>
 * The Polygonizer reports the follow kinds of errors:
 * <ul>
 * <li><b>Dangles</b> - edges which have one or both ends which are not incident on another edge endpoint
 * <li><b>Cut Edges</b> - edges which are connected at both ends but which do not form part of polygon
 * <li><b>Invalid Ring Lines</b> - edges which form rings which are invalid
 * (e.g. the component lines contain a self-intersection)
 * </ul>
 *
 */
class Polygonizer {
private:
	/**
	* Add every linear element in a geometry into the polygonizer graph.
	*/
	class LineStringAdder: public GeometryComponentFilter {
	public:
		Polygonizer *pol;
		LineStringAdder(Polygonizer *p);
		void filter_rw(Geometry *g);
		void filter_ro(const Geometry *g){};
	};

	// default factory
	LineStringAdder *lineStringAdder;

	/**
	* Add a linestring to the graph of polygon edges.
	*
	* @param line the {@link LineString} to add
	*/
	void add(LineString *line);
	/**
	* Perform the polygonization, if it has not already been carried out.
	*/
	void polygonize();
	void findValidRings(vector<polygonizeEdgeRing*> *edgeRingList, vector<polygonizeEdgeRing*> *validEdgeRingList, vector<LineString*> *invalidRingList);
	void findShellsAndHoles(vector<polygonizeEdgeRing*> *edgeRingList);
	static void assignHolesToShells(vector<polygonizeEdgeRing*> *holeList,vector<polygonizeEdgeRing*> *shellList);
	static void assignHoleToShell(polygonizeEdgeRing *holeER,vector<polygonizeEdgeRing*> *shellList);
protected:
	PolygonizeGraph *graph;

	// initialize with empty collections, in case nothing is computed
	vector<const LineString*> *dangles;
	vector<const LineString*> *cutEdges;
	vector<LineString*> *invalidRingLines;

	vector<polygonizeEdgeRing*> *holeList;
	vector<polygonizeEdgeRing*> *shellList;
	vector<Polygon*> *polyList;

public:

	/*
	 * Create a polygonizer with the same GeometryFactory
	 * as the input Geometry
	 */
	Polygonizer();

	~Polygonizer();

	/*
	 * Add a collection of geometries to be polygonized.
	 * May be called multiple times.
	 * Any dimension of Geometry may be added;
	 * the constituent linework will be extracted and used
	 *
	 * @param geomList a list of Geometry with linework to be polygonized
	 */
	void add(vector<Geometry*> *geomList);

	/**
	 * Add a geometry to the linework to be polygonized.
	 * May be called multiple times.
	 * Any dimension of Geometry may be added;
	 * the constituent linework will be extracted and used
	 *
	 * @param g a Geometry with linework to be polygonized
	 */
	void add(Geometry *g);

	/**
	 * Gets the list of polygons formed by the polygonization.
	 * Ownership of vector is transferred to caller, subsequent
	 * calls will return NULL.
	 * @return a collection of Polygons
	 */
	vector<Polygon*>* getPolygons();

	/**
	 * Get the list of dangling lines found during polygonization.
	 * @return a collection of the input LineStrings which are dangles
	 */
	vector<const LineString*>* getDangles();


	/**
	 * Get the list of cut edges found during polygonization.
	 * @return a collection of the input LineStrings which are cut edges
	 */
	vector<const LineString*>* getCutEdges();

	/*
	 * Get the list of lines forming invalid rings found during
	 * polygonization.
	 * Ownership is tranferred to caller, second call will return
	 * NULL (unless polygonize is called again).
	 * @return a collection of LineStrings which form
	 * invalid rings
	 */
	vector<LineString*>* getInvalidRingLines();

// This seems to be needed by    GCC 2.95.4
friend class Polygonizer::LineStringAdder;
};

} // namespace geos
#endif

/**********************************************************************
 * $Log: opPolygonize.h,v $
 * Revision 1.7.2.1  2005/05/23 17:23:15  strk
 * Commented out Polygonizer::LineStringAdder friendship
 *
 * Revision 1.7  2004/12/14 10:35:44  strk
 * Comments cleanup. PolygonizeGraph keeps track of generated CoordinateSequence
 * for delayed destruction.
 *
 * Revision 1.6  2004/12/13 13:54:42  strk
 * Added a not about gcc 2.95.4 required friendship
 *
 * Revision 1.5  2004/10/19 19:51:14  strk
 * Fixed many leaks and bugs in Polygonizer.
 * Output still bogus.
 *
 * Revision 1.4  2004/10/13 10:03:02  strk
 * Added missing linemerge and polygonize operation.
 * Bug fixes and leaks removal from the newly added modules and
 * planargraph (used by them).
 * Some comments and indentation changes.
 *
 * Revision 1.3  2004/07/19 13:19:31  strk
 * Documentation fixes
 *
 * Revision 1.2  2004/07/08 19:34:49  strk
 * Mirrored JTS interface of CoordinateSequence, factory and
 * default implementations.
 * Added DefaultCoordinateSequenceFactory::instance() function.
 *
 * Revision 1.1  2004/07/02 13:20:42  strk
 * Header files moved under geos/ dir.
 *
 * Revision 1.1  2004/04/08 04:53:56  ybychkov
 * "operation/polygonize" ported from JTS 1.4
 *
 *
 **********************************************************************/