Application: gvSIG desktop

package com.iver.cit.gvsig.project.documents.view.snapping.snappers;

import java.awt.Graphics;

import java.awt.geom.PathIterator;

import java.awt.geom.Point2D;

import com.iver.andami.PluginServices;

import com.iver.cit.gvsig.fmap.core.FArc2D;

import com.iver.cit.gvsig.fmap.core.FCircle2D;

import com.iver.cit.gvsig.fmap.core.FEllipse2D;

import com.iver.cit.gvsig.fmap.core.FSpline2D;

import com.iver.cit.gvsig.fmap.core.IGeometry;

import com.iver.cit.gvsig.fmap.core.v02.FConverter;

import com.iver.cit.gvsig.project.documents.view.snapping.AbstractSnapper;

import com.iver.cit.gvsig.project.documents.view.snapping.ISnapperVectorial;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.LineSegment;

/**

 * Tangent point snapper.

 *

 * @author Vicente Caballero Navarro

 */

public class TangentPointSnapper extends AbstractSnapper

    implements ISnapperVectorial {

        /* (non-Javadoc)

     * @see com.iver.cit.gvsig.gui.cad.snapping.ISnapper#getSnapPoint(Point2D point,

     * IGeometry geom,double tolerance, Point2D lastPointEntered)

     */

    public Point2D getSnapPoint(Point2D point, IGeometry geom,

        double tolerance, Point2D lastPointEntered) {

        if (!(geom.getInternalShape() instanceof FCircle2D ||

                geom.getInternalShape() instanceof FArc2D ||

                geom.getInternalShape() instanceof FEllipse2D ||

                geom.getInternalShape() instanceof FSpline2D)) {

            return null;

        }

        Point2D resul = null;

        Coordinate c = new Coordinate(point.getX(), point.getY());

        PathIterator theIterator = geom.getPathIterator(null,

                FConverter.FLATNESS);

        double[] theData = new double[6];

        double minDist = tolerance;

        Coordinate from = null;

        Coordinate first = null;

        while (!theIterator.isDone()) {

            //while not done

            int theType = theIterator.currentSegment(theData);

            switch (theType) {

            case PathIterator.SEG_MOVETO:

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

                first = from;

                break;

            case PathIterator.SEG_LINETO:

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

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

                LineSegment line = new LineSegment(from, to);

                Coordinate closestPoint = line.closestPoint(c);

                double dist = c.distance(closestPoint);

                if ((dist < minDist)) {

                    resul = new Point2D.Double(closestPoint.x, closestPoint.y);

                    minDist = dist;

                }

                from = to;

                break;

            case PathIterator.SEG_CLOSE:

                line = new LineSegment(from, first);

                closestPoint = line.closestPoint(c);

                dist = c.distance(closestPoint);

                if ((dist < minDist)) {

                    resul = new Point2D.Double(closestPoint.x, closestPoint.y);

                    minDist = dist;

                }

                from = first;

                break;

            } //end switch

            theIterator.next();

        }

        return resul;

    }

    /* (non-Javadoc)

     * @see com.iver.cit.gvsig.gui.cad.snapping.ISnapper#getToolTipText()

     */

    public String getToolTipText() {

        return PluginServices.getText(this, "tangent_point");

    }

    /* (non-Javadoc)

     * @see com.iver.cit.gvsig.gui.cad.snapping.ISnapper#draw(java.awt.Graphics, java.awt.geom.Point2D)

     */

    public void draw(Graphics g, Point2D pPixels) {

        g.setColor(getColor());

        int half = getSizePixels() / 2;

        g.drawLine((int) (pPixels.getX() - half),

            (int) (pPixels.getY() - half), (int) (pPixels.getX() + half),

            (int) (pPixels.getY() - half));

        g.drawOval((int) (pPixels.getX() - half),

            (int) (pPixels.getY() - half), getSizePixels(), getSizePixels());

    }

}