renderpolicy.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/layer/policy/RenderPolicy.java,v $
// $RCSfile: RenderPolicy.java,v $
// $Revision: 1.2.2.2 $
// $Date: 2005/10/26 15:47:16 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.layer.policy;

import java.awt.Composite;
import java.awt.Graphics;

import com.bbn.openmap.layer.OMGraphicHandlerLayer;
import com.bbn.openmap.omGraphics.OMGraphicList;

/**
 * A policy object that can be used by an OMGraphicHandlerLayer to
 * figure out the best way to paint on the map.
 */
public interface RenderPolicy {

    /**
     * A method to set the parent layer on the RenderPolicy.
     */
    public void setLayer(OMGraphicHandlerLayer layer);

    /**
     * A method to get the parent layer on the RenderPolicy.
     */
    public OMGraphicHandlerLayer getLayer();

    /**
     * Set a Composite object on a Graphics2D object before rendering.
     * Set to null (default) to not do anything.
     */
    public void setComposite(Composite composite);

    public Composite getComposite();

    /**
     * Called when an OMGraphicHandlerLayer should begin preparing
     * OMGraphics for the map. This is a hook into the list to help
     * RenderPolicy make decisions or set up the list for faster
     * rendering.
     */
    public OMGraphicList prepare();

    /**
     * Called from OMGraphicHandlerLayer.paint(Graphics), so the
     * policy can handle the painting for the layer. If you are going
     * to change the Graphics object in this method, you should make a
     * copy of it first using the Graphics.create() method so the
     * changes won't affect other layers.
     */
    public void paint(Graphics g);

}