omarealist.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
//  10 Moulton Street
//  Cambridge, MA 02138
//  [phone]
// 
//  Copyright (C) BBNT Solutions LLC. All rights reserved.
// 
// </copyright>
// **********************************************************************
// 
// $Source: /cvs/distapps/openmap/src/openmap/com/bbn/openmap/omGraphics/OMAreaList.java,v $
// $RCSfile: OMAreaList.java,v $
// $Revision: 1.6.2.3 $
// $Date: 2005/01/10 16:59:43 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.omGraphics;

import java.awt.geom.GeneralPath;
import java.io.Serializable;

import com.bbn.openmap.proj.Projection;
import com.bbn.openmap.util.GraphicList;

/**
 * This class encapsulates a list of OMGeometries that are connected
 * to form one area. Different types of vector OMGeometries can be
 * combined and used to create a unique shape over the map.
 * OMRasterObjects will contribute their shape/size, but not their
 * images. The OMGeometries should be added in a clockwise format.
 * 
 * <P>
 * KNOWN ISSUES: OMAreaLists that wrap around the back of the earth
 * and showing up on both edges of the map are not handled well -
 * you'll end up with lines going horizonally across the map. It's on
 * the todo list to fix this.
 */
public class OMAreaList extends OMGeometryList implements GraphicList,
        Serializable {

    /**
     * Construct an OMAreaList.
     */
    public OMAreaList() {
        super(10);
        init();
    };

    /**
     * Construct an OMAreaList with a capacity to be combined from an
     * initial amount of OMGeometries.
     * 
     * @param initialCapacity the initial capacity of the list
     */
    public OMAreaList(int initialCapacity) {
        super(initialCapacity);
        init();
    };

    /**
     * Construct an OMAreaList around a List of OMGeometries. The
     * OMAreaList assumes that all the objects on the list are vector
     * OMGeometries, and never does checking. Live with the
     * consequences if you put other stuff in there.
     * 
     * @param list List of vector OMGeometries.
     */
    public OMAreaList(java.util.List list) {
        super(list);
        init();
    }

    /**
     * Initialization that sets the OMAreaList, which is a modified
     * OMGraphicList, to be vague and constructed in a first added,
     * first used order. connectParts, a variable from OMGeometryList,
     * is also set to true.
     */
    protected void init() {
        setVague(true);
        setTraverseMode(LAST_ADDED_ON_TOP);
        setConnectParts(true);
    }

    /**
     * Create the GeneralPath used for the internal Shape objects held
     * by the OMGeometries added. With the OMAreaList, all of the
     * components are combined to make a single area. So updateShape,
     * which is called from super.generate(), calls appendShapeEdge()
     * instead of appending each part Shape to the main Shape. This
     * method closes off the GeneralPath Shape, so it will be
     * considered a polygon.
     */
    public synchronized void generate(Projection p, boolean forceProjectAll) {
        super.generate(p, forceProjectAll);
        if (shape != null) {
            shape.closePath();
        }
    }

    /**
     * Given a OMGeometry, it calls generate/regenerate on it, and
     * then adds the GeneralPath shape within it to the OMGeometryList
     * shape object. The edges of each part are combined to make one
     * big polygon.
     */
    protected void updateShape(OMGeometry geometry, Projection p,
                               boolean forceProject) {
        if (forceProject) {
            geometry.generate(p);
        } else {
            geometry.regenerate(p);
        }

        if (geometry.isVisible()) {
            GeneralPath gp = (GeneralPath) geometry.getShape();

            if (gp == null) {
                return;
            }

            shape = appendShapeEdge(shape, gp, connectParts);
            // save memory?? by deleting the shape in each part, since
            // they are each contributing to the whole.
            geometry.setShape((GeneralPath) null);
        }
    }

    /**
     * Overrides the OMGeometryList and OMGraphicList methods to just
     * call _distance() on the internal shape object.
     * 
     * @param x x coord
     * @param y y coord
     * @param limit the max distance that a graphic has to be within
     *        to be returned, in pixels.
     * @param resetSelect deselect any OMGraphic touched.
     * @return OMDist
     */
    protected synchronized OMDist _findClosest(int x, int y, float limit,
                                               boolean resetSelect) {

        OMDist omd = new OMDist();
        float currentDistance = Float.MAX_VALUE;

        // cannot select a graphic which isn't visible
        if (!isVisible()) {
            omd.omg = null;
        } else {
            if (resetSelect)
                deselect();
            currentDistance = _distance(x, y);
        }

        if (currentDistance < limit) {
            omd.omg = this;
            omd.d = currentDistance;
        }

        return omd;
    }

}