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;

        MultiPoint intersections =

            (MultiPoint) arcToBeSplitted.intersection(splitter);

        if (intersections == null) {

            return geometryToBeSplitted;

        }

        // 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 < intersections.getPrimitivesNumber(); i++) {

            orderedIntersectionPoints.add(intersections.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;

    }

}