geocrossdemolayer.java

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

// **********************************************************************
//
//<copyright>
//
//BBN Technologies, a Verizon Company
//10 Moulton Street
//Cambridge, MA 02138
//[phone]
//
//Copyright (C) BBNT Solutions LLC. All rights reserved.
//
//</copyright>
//**********************************************************************
//
//$Source:
///cvs/darwars/ambush/aar/src/com/bbn/ambush/mission/MissionHandler.java,v
//$
//$RCSfile: GeoCrossDemoLayer.java,v $
//$Revision: 1.1.2.1 $
//$Date: 2005/08/09 21:17:55 $
//$Author: dietrick $
//
//**********************************************************************

package com.bbn.openmap.layer.test;

import java.awt.BasicStroke;
import java.awt.Color;
import java.util.Iterator;

import com.bbn.openmap.geo.Geo;
import com.bbn.openmap.geo.Intersection;
import com.bbn.openmap.layer.editor.EditorLayer;
import com.bbn.openmap.omGraphics.OMAction;
import com.bbn.openmap.omGraphics.OMGraphic;
import com.bbn.openmap.omGraphics.OMGraphicList;
import com.bbn.openmap.omGraphics.OMLine;
import com.bbn.openmap.omGraphics.OMPoint;
import com.bbn.openmap.util.Debug;

/**
 * This layer was developed to provide a simple picture of how vector
 * cross products work with Geos to solve intersection problems. The
 * best way to use this class is to turn off all other layers and put
 * the map in Orthographic projection. When the layer is active, a
 * series of buttons will appear in the ToolPanel, allowing you to
 * draw Great Circle lines. It's helpful to change the color of each
 * line before you create it, so you can see the relationship of the
 * line to the previous one drawn.
 * <P>
 * 
 * This layer will interate through the list if drawn lines, looking
 * for the intersection point between consecutive lines. For each
 * line, a point will be drawn in that line's color representing the
 * cross-normalized point for the line's enpoints - that is, it's the
 * point perpendicular to the great circle plane created by the line.
 * You can also think of it as the point that is 90 degrees away from
 * every point on the line. The dotted lines are the path from the
 * previous line's crossNornmalized point and the current line's
 * crossNormalized point. Lastly, the cross-normalization of the end
 * points of the dashed line will result in the point where the
 * original lines would intersect if they are close enough. Depending
 * on the direction that the lines were drawn, that point may actually
 * be the anitpode (on the other side of the sphere) of the point you
 * are interested in, but this layer doesn't bother to investigate
 * that yet.
 * <P>
 * 
 * That's all this layer does.  The properties for this layer are:
 * 
 * <pre>
 *          geocross.class=com.bbn.openmap.layer.test.GeoCrossDemoLayer
 *          geocross.prettyName=GEO Cross Demonstration
 *          geocross.editor=com.bbn.openmap.layer.editor.DrawingEditorTool
 *          geocross.showAttributes=true
 *          geocross.loaders=lines
 *          geocross.mouseModes=Gestures
 *          geocross.lines.class=com.bbn.openmap.tools.drawing.OMLineLoader
 * </pre>
 * 
 * @author dietrick
 */

public class GeoCrossDemoLayer extends EditorLayer {

    protected OMGraphicList lines = new OMGraphicList();

    /**
     * 
     */
    public GeoCrossDemoLayer() {
        super();
    }

    public OMGraphicList prepare() {
        OMGraphicList list = getList();

        if (list == null) {
            list = new OMGraphicList();
        } else {
            list.clear();
        }

        OMLine oldLine = null;
        Geo ogc = null;

        for (Iterator it = lines.iterator(); it.hasNext();) {

            OMLine line = (OMLine) it.next();
            float[] ll = line.getLL();
            Geo g1 = new Geo(ll[0], ll[1]);
            Geo g2 = new Geo(ll[2], ll[3]);

            Geo gc = g1.crossNormalize(g2);

            OMPoint p = new OMPoint((float) gc.getLatitude(), (float) gc.getLongitude(), 3);
            p.setLinePaint(line.getLinePaint());
            p.setFillPaint(line.getFillPaint());
            p.setStroke(line.getStroke());

            line.addArrowHead(true);

            list.add(line);
            list.add(p);

            if (oldLine != null) {

                float[] ll2 = oldLine.getLL();
                Geo g3 = new Geo(ll2[0], ll2[1]);
                Geo g4 = new Geo(ll2[2], ll2[3]);

                OMLine line2 = new OMLine((float) ogc.getLatitude(), (float) ogc.getLongitude(), (float) gc.getLatitude(), (float) gc.getLongitude(), OMGraphic.LINETYPE_GREATCIRCLE);
                line2.setLinePaint(line.getLinePaint());
                line2.setStroke(new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0f, new float[] {
                        10, 10 }, 0f));
                line2.addArrowHead(true);
                list.add(line2);

                Geo i = gc.crossNormalize(ogc);

                if (!(Intersection.isOnSegment(g1, g2, i) || Intersection.isOnSegment(g3,
                        g4,
                        i))) {
                    i = i.antipode();
                }

                p = new OMPoint((float) i.getLatitude(), (float) i.getLongitude(), 3);
                p.setOval(true);
                p.setLinePaint(line.getLinePaint());
                p.setFillPaint(Color.white);
                p.setStroke(line.getStroke());

                list.add(p);
            }

            oldLine = line;
            ogc = gc;
        }

        list.generate(getProjection());

        return list;

    }

    public void drawingComplete(OMGraphic omg, OMAction action) {

        releaseProxyMouseMode();

        if (omg instanceof OMLine && lines != null) {
            lines.doAction(omg, action);
            deselect(lines);
            doPrepare();
        } else {
            Debug.error("Layer " + getName() + " received " + omg + " and "
                    + action + " with no list ready");
        }

        // This is important!!
        if (editorTool != null) {
            editorTool.drawingComplete(omg, action);
        }
    }

}