Application: gvSIG desktop

/* gvSIG. Desktop Geographic Information System.

 *

 * Copyright ? 2007-2015 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.fmap.geom.jts.util;

import java.util.ArrayList;

import java.util.Collection;

import com.vividsolutions.jts.algorithm.distance.DistanceToPoint;

import com.vividsolutions.jts.algorithm.distance.PointPairDistance;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.LineString;

import com.vividsolutions.jts.operation.buffer.BufferOp;

import com.vividsolutions.jts.operation.buffer.BufferParameters;

import com.vividsolutions.jts.operation.linemerge.LineMerger;

import org.cresques.cts.IProjection;

import org.gvsig.fmap.geom.Geometry;

/**

 * Based on portions of code from OpenJump

 *

 */

public class OpenJUMPUtils {

    /**

     * Creates a offset of a open line at a distance by removing segments that do not match the limit of the buffer.

     *

     * @param proj

     * @param coordinates

     * @param distance

     * @return

     */

    public static Geometry offsetCleanOpenLine(IProjection proj, ArrayListCoordinateSequence coordinates, double distance) {

        com.vividsolutions.jts.geom.GeometryFactory factory = JTSUtils.getFactory(coordinates);

        LineString jtsGeom = JTSUtils.createJTSLineString(proj, coordinates);

        BufferParameters bufParams = JTSUtils.getBufferParameters();

        com.vividsolutions.jts.geom.Geometry sidedBuffer =

            new BufferOp(jtsGeom, bufParams).getResultGeometry(distance).getBoundary();

        Collection<LineString> offsetSegments = new ArrayList<>();

        // Segments located entirely under this distance are excluded

        int quadrantSegments = bufParams.getQuadrantSegments();

        double lowerBound = Math.abs(distance) * Math.sin(Math.PI / (4 * quadrantSegments));

        // Segments located entirely over this distance are included

        // note that the theoretical approximation made with quadrantSegments

        // is offset*cos(PI/(4*quadrantSegments) but

        // offset*cos(PI/(2*quadrantSegments)

        // is used to make sure to include segments located on the boundary

        double upperBound = Math.abs(distance) * Math.cos(Math.PI / (2 * quadrantSegments));

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

            Coordinate[] cc = sidedBuffer.getGeometryN(i).getCoordinates();

            PointPairDistance ppd = new PointPairDistance();

            DistanceToPoint.computeDistance(jtsGeom, cc[0], ppd);

            double dj = ppd.getDistance();

            for (int j = 1; j < cc.length; j++) {

                double di = dj;

                ppd = new PointPairDistance();

                DistanceToPoint.computeDistance(jtsGeom, cc[j], ppd);

                dj = ppd.getDistance();

                // segment along or touching the source geometry : eclude it

                if (Math.max(di, dj) < lowerBound || di == 0 || dj == 0) {

                    continue;

                }

                // segment along the buffer boundary : include it

                else if (Math.min(di, dj) > upperBound) {

                    LineString segment = jtsGeom.getFactory().createLineString(new Coordinate[] { cc[j - 1], cc[j] });

                    offsetSegments.add(segment);

                }

                // segment entirely located inside the buffer : exclude it

                else if (Math.min(di, dj) > lowerBound && Math.max(di, dj) < upperBound) {

                    continue;

                }

                // segment with a end at the offset distance and the other

                // located within the buffer : divide it

                else {

                    // One of the coordinates is closed to but not on the source

                    // curve and the other is more or less closed to offset

                    // distance

                    divide(offsetSegments, jtsGeom, cc[j - 1], cc[j], di, dj, lowerBound, upperBound);

                }

            }

        }

        Collection<LineString> offsetCurves = new ArrayList<LineString>();

        offsetCurves.addAll(merge(offsetSegments));

        return JTSUtils.createGeometry(proj, factory.buildGeometry(offsetCurves));

    }

    /**

     * Creates a offset of a open line at a distance by removing segments that do not match the limit of the buffer.

     *

     * @param proj

     * @param coordinates

     * @param bufParams

     * @param distance

     * @return

     */

    public static Geometry offsetCleanOpenLine(IProjection proj, ArrayListCoordinateSequence coordinates, BufferParameters bufParams, double distance) {

        com.vividsolutions.jts.geom.GeometryFactory factory = JTSUtils.getFactory(coordinates);

        LineString jtsGeom = JTSUtils.createJTSLineString(proj, coordinates);

//        BufferParameters bufParams = JTSUtils.getBufferParameters();

        com.vividsolutions.jts.geom.Geometry sidedBuffer =

            new BufferOp(jtsGeom, bufParams).getResultGeometry(distance).getBoundary();

        Collection<LineString> offsetSegments = new ArrayList<>();

        // Segments located entirely under this distance are excluded

        int quadrantSegments = bufParams.getQuadrantSegments();

        double lowerBound = Math.abs(distance) * Math.sin(Math.PI / (4 * quadrantSegments));

        // Segments located entirely over this distance are included

        // note that the theoretical approximation made with quadrantSegments

        // is offset*cos(PI/(4*quadrantSegments) but

        // offset*cos(PI/(2*quadrantSegments)

        // is used to make sure to include segments located on the boundary

        double upperBound = Math.abs(distance) * Math.cos(Math.PI / (2 * quadrantSegments));

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

            Coordinate[] cc = sidedBuffer.getGeometryN(i).getCoordinates();

            PointPairDistance ppd = new PointPairDistance();

            DistanceToPoint.computeDistance(jtsGeom, cc[0], ppd);

            double dj = ppd.getDistance();

            for (int j = 1; j < cc.length; j++) {

                double di = dj;

                ppd = new PointPairDistance();

                DistanceToPoint.computeDistance(jtsGeom, cc[j], ppd);

                dj = ppd.getDistance();

                // segment along or touching the source geometry : eclude it

                if (Math.max(di, dj) < lowerBound || di == 0 || dj == 0) {

                    continue;

                }

                // segment along the buffer boundary : include it

                else if (Math.min(di, dj) > upperBound) {

                    LineString segment = jtsGeom.getFactory().createLineString(new Coordinate[] { cc[j - 1], cc[j] });

                    offsetSegments.add(segment);

                }

                // segment entirely located inside the buffer : exclude it

                else if (Math.min(di, dj) > lowerBound && Math.max(di, dj) < upperBound) {

                    continue;

                }

                // segment with a end at the offset distance and the other

                // located within the buffer : divide it

                else {

                    // One of the coordinates is closed to but not on the source

                    // curve and the other is more or less closed to offset

                    // distance

                    divide(offsetSegments, jtsGeom, cc[j - 1], cc[j], di, dj, lowerBound, upperBound);

                }

            }

        }

        Collection<LineString> offsetCurves = new ArrayList<LineString>();

        offsetCurves.addAll(merge(offsetSegments));

        return JTSUtils.createGeometry(proj, factory.buildGeometry(offsetCurves));

    }

    /**

     * Recursive function to split segments located on the single-side buffer

     * boundary, but having a part of them inside the full buffer.

     *

     * @param offsetSegments

     * @param sourceCurve

     * @param c1

     * @param c2

     * @param d1

     * @param d2

     * @param lb

     * @param ub

     */

    private static void divide(Collection<LineString> offsetSegments, com.vividsolutions.jts.geom.Geometry sourceCurve,

            Coordinate c1, Coordinate c2, double d1, double d2, double lb, double ub) {

        // I stop recursion for segment < 2*lb to exclude small segments

        // perpendicular but very close to the boundary

        if (c1.distance(c2) < 2*lb) return;

        Coordinate c = new Coordinate((c1.x+c2.x)/2.0, (c1.y+c2.y)/2.0);

        PointPairDistance ppd = new PointPairDistance();

        DistanceToPoint.computeDistance(sourceCurve, c, ppd);

        double d = ppd.getDistance();

        if (Math.max(d1, d) < lb) {}

        else if (Math.min(d1, d) > lb && Math.max(d1, d) < ub) {}

        else if (Math.min(d1, d) > ub) {

            LineString segment = sourceCurve.getFactory().createLineString(

                        new Coordinate[]{c1, c});

            offsetSegments.add(segment);

        }

        else {

            divide(offsetSegments, sourceCurve, c1, c, d1, d, lb, ub);

        }

        if (Math.max(d, d2) < lb) {}

        else if (Math.min(d, d2) > lb && Math.max(d, d2) < ub) {}

        else if (Math.min(d, d2) > ub) {

            LineString segment = sourceCurve.getFactory().createLineString(

                        new Coordinate[]{c, c2});

            offsetSegments.add(segment);

        }

        else {

            divide(offsetSegments, sourceCurve, c, c2, d, d2, lb, ub);

        }

    }

    @SuppressWarnings("unchecked")

    private static Collection<LineString> merge(Collection<LineString> linestrings) {

        LineMerger merger = new LineMerger();

        merger.add(linestrings);

        return merger.getMergedLineStrings();

    }

}