Application: gvSIG desktop » gvSIG tools: Vector editing

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright ? 2007-2014 gvSIG Association

 *

 * 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., 51 Franklin Street, Fifth Floor, Boston,

 * MA  02110-1301, USA.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.vectorediting.lib.prov.split.operation;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.gvsig.fmap.geom.Geometry;

import org.gvsig.fmap.geom.GeometryLocator;

import org.gvsig.fmap.geom.GeometryManager;

import org.gvsig.fmap.geom.aggregate.MultiCurve;

import org.gvsig.fmap.geom.aggregate.MultiPoint;

import org.gvsig.fmap.geom.exception.CreateGeometryException;

import org.gvsig.fmap.geom.operation.GeometryOperationException;

import org.gvsig.fmap.geom.operation.GeometryOperationNotSupportedException;

import org.gvsig.fmap.geom.primitive.Arc;

import org.gvsig.fmap.geom.primitive.Point;

import org.gvsig.tools.exception.BaseException;

/**

 * @author llmarques

 *

 */

public class ArcSplitOperation implements SplitOperation {

    private static Logger logger = LoggerFactory

        .getLogger(ArcSplitOperation.class);

    /*

     * Strategy:

     * 

     * 1. Get intersection points.

     * 2. Get center and radius

     * 3. Order intersections points by angle

     * 4. Iterate over ordered intersection points and create splitted arcs.

     * Stop iteration when all intersections points have been iterated.

     */

    public Geometry split(Geometry geometryToBeSplitted, Geometry splitter)

        throws GeometryOperationNotSupportedException,

        GeometryOperationException, CreateGeometryException {

        int subtype = geometryToBeSplitted.getGeometryType().getSubType();

        GeometryManager geoManager = GeometryLocator.getGeometryManager();

        Arc arcToBeSplitted = (Arc) geometryToBeSplitted;

        Geometry intersections = arcToBeSplitted.intersection(splitter);

        if (intersections == null) {

            return geometryToBeSplitted;

        } else if (intersections instanceof Point) {

            if(isClosed(arcToBeSplitted)){ // Closed arcs can be splitted by one point

                return arcToBeSplitted;

            } else {

                return arcToBeSplitted.difference(splitter);

            }

        } else if (intersections instanceof MultiPoint) {

            // Two or more intersection points

            MultiPoint multiIntersection = (MultiPoint) intersections;

            // Arc#getCenterPoint can return null if two points of arc are the

            // same

            Point tmpCenter = arcToBeSplitted.getCenterPoint();

            if (tmpCenter == null) {

                // If center is null, we use this "trick". Get center of arc

                // envelope.

                tmpCenter =

                    SplitOperationUtils.createPoint(arcToBeSplitted

                        .getEnvelope().getCenter(0), arcToBeSplitted

                        .getEnvelope().getCenter(1), subtype);

            }

            final Point center = tmpCenter;

            double radius = center.distance(arcToBeSplitted.getEndPoint());

            // Order intersection points by angle to create arcs correctly

            List<Point> orderedIntersectionPoints = new ArrayList<Point>();

            for (int i = 0; i < multiIntersection.getPrimitivesNumber(); i++) {

                orderedIntersectionPoints.add(multiIntersection.getPointAt(i));

            }

            // Sort by angle

            Collections.sort(orderedIntersectionPoints,

                new Comparator<Point>() {

                    public int compare(Point p1, Point p2) {

                        double angle1 = 0;

                        double angle2 = 0;

                        try {

                            angle1 = SplitOperationUtils.getAngle(center, p1);

                            angle2 = SplitOperationUtils.getAngle(center, p2);

                        } catch (BaseException e) {

                            logger

                                .warn("Problems getting angle between center and"

                                    + " one intersection point");

                            return 0;

                        }

                        return Double.compare(angle1, angle2);

                    }

                });

            MultiCurve splittedArcs = geoManager.createMultiCurve(subtype);

            for (int i = 0; i < orderedIntersectionPoints.size(); i++) {

                Point intersecctionPoint = orderedIntersectionPoints.get(i);

                Point nextIntersecctionPoint;

                if (i + 1 >= orderedIntersectionPoints.size()) {

                    nextIntersecctionPoint = orderedIntersectionPoints.get(0);

                } else {

                    nextIntersecctionPoint =

                        orderedIntersectionPoints.get(i + 1);

                }

                double angle1 =

                    SplitOperationUtils.getAngle(center, intersecctionPoint);

                double angle2 =

                    SplitOperationUtils

                        .getAngle(center, nextIntersecctionPoint);

                Arc arc = (Arc) geoManager.create(Geometry.TYPES.ARC, subtype);

                arc.setPointsStartEnd(center, radius, angle1, angle2);

                splittedArcs.addCurve(arc);

            }

            return splittedArcs;

        }

        return arcToBeSplitted;

    }

    private boolean isClosed(Arc arc) {

        Point initPoint = arc.getInitPoint();

        Point endPoint = arc.getEndPoint();

        Point centerPoint = arc.getCenterPoint();

        if(initPoint.equals(endPoint) || centerPoint == null){

            return true;

        }

        return false;

    }

}