Application: gvSIG desktop

/*

 * Created on 06-oct-2006

 *

 * gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib??ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

/* CVS MESSAGES:

*

* $Id: SnapPointLocator.java 9178 2006-12-04 19:30:23Z azabala $

* $Log$

* Revision 1.1  2006-12-04 19:29:31  azabala

* *** empty log message ***

*

* Revision 1.1  2006/10/17 18:25:53  azabala

* *** empty log message ***

*

* Revision 1.1  2006/10/09 19:10:56  azabala

* First version in CVS

*

*

*/

package com.vividsolutions.jts.algorithms;

import java.util.Iterator;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.Geometry;

import com.vividsolutions.jts.geom.GeometryCollection;

import com.vividsolutions.jts.geom.GeometryCollectionIterator;

import com.vividsolutions.jts.geom.LineString;

import com.vividsolutions.jts.geom.LinearRing;

import com.vividsolutions.jts.geom.Location;

import com.vividsolutions.jts.geom.MultiLineString;

import com.vividsolutions.jts.geom.MultiPolygon;

import com.vividsolutions.jts.geom.Polygon;

import com.vividsolutions.jts.geomgraph.SnappingGeometryGraph;

public class SnapPointLocator extends com.vividsolutions.jts.algorithm.PointLocator {

         private boolean isIn;         // true if the point lies in or on any Geometry element

          private int numBoundaries;    // the number of sub-elements whose boundaries the point lies in

          public SnapPointLocator() {

          }

          /**

           * Convenience method to test a point for intersection with

           * a Geometry

           * @param p the coordinate to test

           * @param geom the Geometry to test

           * @return <code>true</code> if the point is in the interior or boundary of the Geometry

           */

          public boolean intersects(Coordinate p, Geometry geom, double snapTolerance)

          {

            return locate(p, geom, snapTolerance) != Location.EXTERIOR;

          }

          /**

           * Computes the topological relationship ({@link Location}) of a single point

           * to a Geometry.

           * It handles both single-element

           * and multi-element Geometries.

           * The algorithm for multi-part Geometries

           * takes into account the SFS Boundary Determination Rule.

           *

           * @return the {@link Location} of the point relative to the input Geometry

           */

          public int locate(Coordinate p, Geometry geom, double snapTolerance)

          {

            if (geom.isEmpty()) return Location.EXTERIOR;

            if (geom instanceof LinearRing) {

              return locate(p, (LinearRing) geom, snapTolerance);

            }

            if (geom instanceof LineString) {

              return locate(p, (LineString) geom, snapTolerance);

            }

            else if (geom instanceof Polygon) {

              return locate(p, (Polygon) geom, snapTolerance);

            }

            isIn = false;

            numBoundaries = 0;

            computeLocation(p, geom, snapTolerance);

            if (SnappingGeometryGraph.isInBoundary(numBoundaries)) 

                    return Location.BOUNDARY;

            if (numBoundaries > 0 || isIn) 

                    return Location.INTERIOR;

            return Location.EXTERIOR;

          }

          private void computeLocation(Coordinate p, Geometry geom, double snapTolerance)

          {

            if (geom instanceof LinearRing) {

              updateLocationInfo(locate(p, (LinearRing) geom, snapTolerance));

            }

            if (geom instanceof LineString) {

              updateLocationInfo(locate(p, (LineString) geom, snapTolerance));

            }

            else if (geom instanceof Polygon) {

              updateLocationInfo(locate(p, (Polygon) geom, snapTolerance));

            }

            else if (geom instanceof MultiLineString) {

              MultiLineString ml = (MultiLineString) geom;

              for (int i = 0; i < ml.getNumGeometries(); i++) {

                LineString l = (LineString) ml.getGeometryN(i);

                updateLocationInfo(locate(p, l, snapTolerance));

              }

            }

            else if (geom instanceof MultiPolygon) {

              MultiPolygon mpoly = (MultiPolygon) geom;

              for (int i = 0; i < mpoly.getNumGeometries(); i++) {

                Polygon poly = (Polygon) mpoly.getGeometryN(i);

                updateLocationInfo(locate(p, poly, snapTolerance));

              }

            }

            else if (geom instanceof GeometryCollection) {

              Iterator geomi = new GeometryCollectionIterator((GeometryCollection) geom);

              while (geomi.hasNext()) {

                Geometry g2 = (Geometry) geomi.next();

                if (g2 != geom)

                  computeLocation(p, g2, snapTolerance);

              }

            }

          }

          private void updateLocationInfo(int loc)

          {

            if (loc == Location.INTERIOR) isIn = true;

            if (loc == Location.BOUNDARY) numBoundaries++;

          }

          private int locate(Coordinate p, LineString l, double snapTolerance)

          {

            Coordinate[] pt = l.getCoordinates();

            if (! l.isClosed()) {

              if (p.distance(pt[0]) <= snapTolerance

                  || p.distance(pt[pt.length - 1]) <= snapTolerance ) {

                return Location.BOUNDARY;

              }

            }

            if (SnapCGAlgorithms.isOnLine(p, pt, snapTolerance))

              return Location.INTERIOR;

            return Location.EXTERIOR;

          }

          private int locate(Coordinate p, LinearRing ring, double snapTolerance)

          {

            // can this test be folded into isPointInRing ?

            if (SnapCGAlgorithms.isOnLine(p, ring.getCoordinates())) {

              return Location.BOUNDARY;

            }

            if (SnapCGAlgorithms.isPointInRing(p, ring.getCoordinates(), snapTolerance))

              return Location.INTERIOR;

            return Location.EXTERIOR;

          }

          private int locate(Coordinate p, Polygon poly, double snapTolerance)

          {

            if (poly.isEmpty()) return Location.EXTERIOR;

            LinearRing shell = (LinearRing) poly.getExteriorRing();

            int shellLoc = locate(p, shell, snapTolerance);

            if (shellLoc == Location.EXTERIOR) return Location.EXTERIOR;

            if (shellLoc == Location.BOUNDARY) return Location.BOUNDARY;

            // now test if the point lies in or on the holes

            for (int i = 0; i < poly.getNumInteriorRing(); i++) {

              LinearRing hole = (LinearRing) poly.getInteriorRingN(i);

              int holeLoc = locate(p, hole, snapTolerance);

              if (holeLoc == Location.INTERIOR) return Location.EXTERIOR;

              if (holeLoc == Location.BOUNDARY) return Location.BOUNDARY;

            }

            return Location.INTERIOR;

          }

}