| gvSIG desktop 1

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

 *

 * Copyright (C) 2005 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

 */

package org.gvsig.fmap.mapcontext.rendering.symbols.styles;

import java.awt.Shape;

import java.awt.geom.Line2D;

import java.awt.geom.PathIterator;

import java.awt.geom.Point2D;

import java.util.ArrayList;

import java.util.Hashtable;

import org.apache.log4j.Logger;

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

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.LineSegment;

/**

 *

 * Line2DOffset.java

 *

 *

 * @author jaume dominguez faus - jaume.dominguez@iver.es Jan 3, 2008

 *

 */

public class Line2DOffset {

        public static GeneralPathX offsetLine(Shape p, double offset) {

                if (Math.abs(offset) <= 1) {

                        return new GeneralPathX(p);

                }

                PathIterator pi = p.getPathIterator(null);

                double[] dataCoords = new double[6];

                Coordinate from = null, first = null;

                ArrayList<LineSegment> segments = new ArrayList<LineSegment>();

                GeneralPathX offsetSegments = new GeneralPathX();

                try {

                        while (!pi.isDone()) {

                                // while not done

                                int type = pi.currentSegment(dataCoords);

                                switch (type) {

                                case PathIterator.SEG_MOVETO:

                                        from = new Coordinate(dataCoords[0], dataCoords[1]);

                                        first = from;

                                        break;

                                case PathIterator.SEG_LINETO:

                                        // System.out.println("SEG_LINETO");

                                        Coordinate to = new Coordinate(dataCoords[0], dataCoords[1]);

                                        LineSegment line = new LineSegment(from, to);

                                        segments.add(line);

                                        from = to;

                                        break;

                                case PathIterator.SEG_CLOSE:

                                        line = new LineSegment(from, first);

                                        segments.add(line);

                                        from = first;

                                        try {

                                                offsetSegments.append(offsetAndConsumeClosedSegments(

                                                                offset, segments), false);

                                        } catch (NotEnoughSegmentsToClosePathException e) {

                                                Logger.getLogger(Line2DOffset.class).error(

                                                                e.getMessage(), e);

                                        }

                                        break;

                                } // end switch

                                pi.next();

                        }

                        offsetSegments.append(offsetAndConsumeSegments(offset, segments),

                                        true);

                        return offsetSegments;

                } catch (ParallelLinesCannotBeResolvedException e) {

                        Logger.getLogger(Line2DOffset.class).error(e.getMessage(), e);

                        return new GeneralPathX(p);

                }

        }

        private static GeneralPathX offsetAndConsumeSegments(double offset,

                        ArrayList<LineSegment> segments)

        throws ParallelLinesCannotBeResolvedException {

                Hashtable<LineSegment, LineEquation> offsetLines = new Hashtable<LineSegment, LineEquation>();

                int segmentCount = segments.size();

                // first calculate offset lines with the starting point

                for (int i = 0; i < segmentCount; i++) {

                        LineSegment segment = segments.get(i);

                        double theta = segment.angle();

                        if (Math.abs(theta) % (Math.PI*0.5) < 0.00001){

                                theta=theta+0.00000000000001;

                        }

                        double xOffset = offset * Math.sin(theta);

                        double yOffset = offset * Math.cos(theta);

                        Coordinate p0 = segment.p0;

                        double x0 = p0.x + xOffset;

                        double y0 = p0.y - yOffset;

                        Coordinate p1 = segment.p1;

                        double x1 = p1.x + xOffset;

                        double y1 = p1.y - yOffset;

                        LineEquation offsetLine = new LineEquation(theta, x0, y0, x1, y1);

                        offsetLines.put(segment, offsetLine);

                }

                /*

                 * let's now calculate the end point of each segment with the point

                 * where each line crosses the next one. this point will be the end

                 * point of the first line, and the start point of its next one.

                 */

                Point2D pIni = null;

                Point2D pEnd = null;

                GeneralPathX gpx = new GeneralPathX();

                for (int i = 0; i < segmentCount; i++) {

                        LineSegment segment = segments.get(0);

                        LineEquation eq = offsetLines.get(segment);

                        if (i == 0) {

                                pIni = new Point2D.Double(eq.x, eq.y);

                        } else {

                                pIni = pEnd;

                        }

                        if (i < segmentCount - 1) {

                                pEnd = eq.resolve(offsetLines.get(segments.get(1)));

                        } else {

                                pEnd = new Point2D.Double(eq.xEnd, eq.yEnd);

                        }

                        gpx.append(new Line2D.Double(pIni, pEnd), true);

                        segments.remove(0);

                }

                return gpx;

        }

        private static GeneralPathX offsetAndConsumeClosedSegments(double offset,

                        ArrayList<LineSegment> segments)

        throws ParallelLinesCannotBeResolvedException,

        NotEnoughSegmentsToClosePathException {

                int segmentCount = segments.size();

                if (segmentCount > 1) {

                        GeneralPathX openPath = offsetAndConsumeSegments(offset, segments);

                        openPath.closePath();

                        return openPath;

                }

                throw new NotEnoughSegmentsToClosePathException(segments);

        }

}

class LineEquation {

        double theta, x, y;

        double xEnd, yEnd; // just for simplicity of code

        public LineEquation(double theta, double x, double y, double xEnd,

                        double yEnd) {

                this.theta = Math.tan(theta);

                this.x = x;

                this.y = y;

                this.xEnd = xEnd;

                this.yEnd = yEnd;

        }

        public Point2D resolve(LineEquation otherLine)

        throws ParallelLinesCannotBeResolvedException {

                /*

                 * line1 (this): y - y0 = m*(x - x0) line2 (otherLine): y' - y'0 =

                 * m'*(x' - x'0)

                 */

                if (otherLine.theta == this.theta) {

                        if (this.xEnd == otherLine.x && this.yEnd == otherLine.y) {

                                return new Point2D.Double(otherLine.x, otherLine.y);

                        }

                        throw new ParallelLinesCannotBeResolvedException(this, otherLine);

                }

                /*

                 * m*(X - x0) + y0 = m'*(X - x'0) + y0' X = (m*x0 - y0 - m'*x0' + y'0) /

                 * (m - m')

                 */

                double thetaTimesX = this.theta * this.x;

                double X = (thetaTimesX - this.y - otherLine.theta * otherLine.x + otherLine.y)

                / (this.theta - otherLine.theta);

                /*

                 * Y - y0 = m*(X - x0) Y = m*X - m*x0 + y0

                 */

                double Y = this.theta * X - thetaTimesX + this.y;

                return new Point2D.Double(X, Y);

        }

        @Override

        public String toString() {

                return "Y - " + y + " = " + theta + "*(X - " + x + ")";

        }

}

class NotEnoughSegmentsToClosePathException extends Exception {

        private static final long serialVersionUID = 95503944546535L;

        public NotEnoughSegmentsToClosePathException(ArrayList<LineSegment> segments) {

                super("Need at least 2 segments to close a path. I've got "

                                + segments.size() + ".");

        }

}

class ParallelLinesCannotBeResolvedException extends Exception {

        private static final long serialVersionUID = 8322556508820067641L;

        public ParallelLinesCannotBeResolvedException(LineEquation eq1,

                        LineEquation eq2) {

                super("Lines '" + eq1 + "' and '" + eq2

                                + "' are parallel and don't share any point!");

        }

}

//public class Line2DOffset {

//private static final double TOL = 1E-8;

//private static final double ANGLE_TOL = 0.01/180*Math.PI;

//public static GeneralPathX offsetLine(Shape p, double offset) {

//PathIterator pi = p.getPathIterator(null);

//double[] dataCoords = new double[6];

//Coordinate from = null, first = null;

//ArrayList<LineSegment> segments = new ArrayList<LineSegment>();

//GeneralPathX offsetSegments = new GeneralPathX();

//try {

//while (!pi.isDone()) {

//// while not done

//int type = pi.currentSegment(dataCoords);

//switch (type) {

//case PathIterator.SEG_MOVETO:

//from = new Coordinate(dataCoords[0], dataCoords[1]);

//first = from;

//break;

//case PathIterator.SEG_LINETO:

//// System.out.println("SEG_LINETO");

//Coordinate to = new Coordinate(dataCoords[0], dataCoords[1]);

//LineSegment line = new LineSegment(from, to);

//int size = segments.size();

//if (size>0) {

//LineSegment prev = segments.get(size-1);

//if (line.angle() == prev.angle()) {

//if (Math.abs(line.p0.x - prev.p1.x) < TOL &&

//Math.abs(line.p0.y - prev.p1.y) < TOL) {

//prev.p1 = line.p1;

//break;

//}

//}

//}

//from = to;

//segments.add(line);

//break;

//case PathIterator.SEG_CLOSE:

//line = new LineSegment(from, first);

//segments.add(line);

//from = first;

//try {

//offsetSegments.append(offsetAndConsumeClosedSegments(offset, segments), false);

//} catch (NotEnoughSegmentsToClosePathException e) {

//Logger.getLogger(Line2DOffset.class).error(e.getMessage(), e);

//}

//break;

//} // end switch

//pi.next();

//}

//offsetSegments.append(offsetAndConsumeSegments(offset, segments), true);

//return offsetSegments;

//} catch (ParallelLinesCannotBeResolvedException e) {

//Logger.getLogger(Line2DOffset.class).error(e.getMessage(), e);

//return new GeneralPathX(p);

//}

//}

//private static GeneralPathX offsetAndConsumeSegments(double offset, ArrayList<LineSegment> segments)  {

//Hashtable<LineSegment, LineEquation> offsetLines = new Hashtable<LineSegment, LineEquation>();

//int segmentCount = segments.size();

//// first calculate offset lines with the starting point

//for (int i = 0; i < segmentCount; i++) {

//LineSegment segment = segments.get(i);

//double theta = segment.angle();

//double xOffset = offset*Math.sin(theta);

//double yOffset = offset*Math.cos(theta);

//Coordinate p0 = segment.p0;

//double x0 = p0.x + xOffset;

//double y0 = p0.y - yOffset;

//Coordinate p1 = segment.p1;

//double x1 = p1.x + xOffset;

//double y1 = p1.y - yOffset;

//LineEquation offsetLine = new LineEquation(theta, x0, y0, x1, y1, offset);

//offsetLines.put(segment, offsetLine);

//}

///*

//* let's now calculate the end point of each segment with

//* the point where each line crosses the next one.

//* this point will be the end point of the first line, and

//* the start point of its next one.

//*/

//Point2D pIni = null;

//Point2D pEnd = null;

//GeneralPathX gpx = new GeneralPathX();

//for (int i = 0; i < segmentCount; i++) {

//LineSegment segment = segments.get(0);

//LineEquation eq = offsetLines.get(segment);

//Point2D pAux = null;

//if (i < segmentCount -1) {

//try {

//pAux = eq.resolve(offsetLines.get(segments.get(1)));

//if (i == 0) {

//pIni = new Point2D.Double(eq.x, eq.y);

//} else {

//pIni = pEnd;

//}

//} catch (ParallelLinesCannotBeResolvedException e) {

//segments.remove(0);

//continue;

//}

//}

//if (pAux != null) {

//pEnd = pAux;

//} else {

//pEnd = new Point2D.Double(eq.xEnd, eq.yEnd);

//}

//gpx.append(new Line2D.Double(pIni, pEnd), true);

//segments.remove(0);

//}

//return gpx;

//}

//private static GeneralPathX offsetAndConsumeClosedSegments(double offset, ArrayList<LineSegment> segments) throws ParallelLinesCannotBeResolvedException, NotEnoughSegmentsToClosePathException {

//int segmentCount = segments.size();

//if (segmentCount > 1) {

//GeneralPathX openPath = offsetAndConsumeSegments(offset, segments);

//openPath.closePath();

//return openPath;

//}

//throw new NotEnoughSegmentsToClosePathException(segments);

//}

//}

//class LineEquation {

//double theta, x, y;

//double xEnd, yEnd; // just for simplicity of code

//double offset;

//public LineEquation(double theta, double x, double y, double xEnd, double yEnd, double offset) {

//this.theta = theta;

//this.x = x;

//this.y = y;

//this.xEnd = xEnd;

//this.yEnd = yEnd;

//this.offset = offset;

//}

//public Point2D resolve(LineEquation otherLine) throws ParallelLinesCannotBeResolvedException {

//double X;

//double Y;

///*

//* line1 (this):      y  -  y0 =  m*(x  - x0)

//* line2 (otherLine): y' - y'0 = m'*(x' - x'0)

//*/

//if (otherLine.theta == this.theta)

//throw new ParallelLinesCannotBeResolvedException(this, otherLine);

//if (Math.cos(theta) == 0) {

//X = otherLine.x + offset*Math.cos(otherLine.theta);

//Y = otherLine.y + offset*Math.sin(otherLine.theta);

//} else if (Math.cos(otherLine.theta) == 0) {

//X = x + offset*Math.cos(theta);

//Y = y + offset*Math.sin(theta);

//} else {

///*

//* m*(X - x0) + y0 = m'*(X - x'0) + y0'

//* X = (m*x0 - y0 - m'*x0' + y'0) / (m - m')

//*/

//double tanTheta = Math.tan(theta);

//double otherTanTheta = Math.tan(otherLine.theta);

//double thetaTimesX = tanTheta*this.x;

//X = (thetaTimesX - this.y - otherTanTheta*otherLine.x + otherLine.y) / (tanTheta - otherTanTheta);

///*

//* Y - y0 = m*(X - x0)

//* Y = m*X - m*x0 + y0

//*/

//Y = tanTheta*X - thetaTimesX + this.y;

//}

//return new Point2D.Double(X, Y);

//}

//@Override

//public String toString() {

//return "Y - "+y+" = "+theta+"*(X - "+x+")";

//}

//}

//class NotEnoughSegmentsToClosePathException extends Exception {

//private static final long serialVersionUID = 95503944546535L;

//public NotEnoughSegmentsToClosePathException(ArrayList<LineSegment> segments) {

//super("Need at least 2 segments to close a path. I've got "+segments.size()+".");

//}

//}

//class ParallelLinesCannotBeResolvedException extends Exception {

//private static final long serialVersionUID = 8322556508820067641L;

//public ParallelLinesCannotBeResolvedException(LineEquation eq1, LineEquation eq2) {

//super("Lines '"+eq1+"' and '"+eq2+"' are parallel and don't share any point!");

//}

//}