bufferedpanel.java

MegaMek is a networked Java clone of BattleTech, a turn-based sci-fi boardgame for 2+ players. Fight

/**
 * MegaMek - Copyright (C) 2003, 2004 Ben Mazur ([e-mail])
 * 
 *  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.
 */
 
package megamek.client.ui.AWT.widget;

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;
import java.util.Enumeration;

/**
 * BufferedPanel required for use PicMap with AWT. To avoid
 * flicker.
 * It is possible to add set of Background Drawers to the Panel.
 */

public class BufferedPanel extends Panel implements ComponentListener {

     //Vector of Background Drawers
     private Vector bgDrawers = new Vector();
     private Dimension preferredSize = new Dimension();

     public BufferedPanel(){
      super();
      addComponentListener(this);
     }
     
     public BufferedPanel(LayoutManager layout){
      super(layout);
      addComponentListener(this);
     }
     
     /**
     * Adds background drawer.
     * Background drawers are drawn in order they added to the component.
     */
    
    public void addBgDrawer(BackGroundDrawer bd){
       bgDrawers.addElement(bd);      
    }
    
    /**
     * Removes Background drawer from panel.
     */
    
    public void removeBgDrawer(BackGroundDrawer bd){
        bgDrawers.removeElement(bd);
    }

    /**
     * Removes all Background drawers from panel.
     */
    
    public void removeBgDrawers(){
        bgDrawers.removeAllElements();
    }

    /**
     * overriden to eliminate flicker.
     */
    public void update(Graphics g) {
        paint(g);
    }

    /**
     * Paint the panel. Must call super.paint() from any subclass that
     * wished to override this to ensure any contained lightweight components
     * get repainted.
     *
     * @param   g - the <code>Graphics</code> to draw onto.
     *          This value may be <code>null</code>.
     */
    public void paint(Graphics g) {
        // No Graphics, no painting.
        if (null == g) {
            return;
        }
        // create an off-screen image
        Image offScr = createImage(getSize().width, getSize().height);
        // Get a Graphics object to draw with.
        Graphics offG = offScr.getGraphics();
        // set clipping to current size.
        offG.setClip(0, 0, getSize().width, getSize().height);
        // Clear the panel as needed 
        clearGraphics(offG);
        //Draw background
        Enumeration iter = bgDrawers.elements();
        while(iter.hasMoreElements()){
            BackGroundDrawer bgd = (BackGroundDrawer) iter.nextElement();
            bgd.drawInto(offG, getSize().width, getSize().height);
        }
        // Let the parent panel repaint the components inside.
        super.paint(offG);
        // draw the off-screen image to the sreen.
        g.drawImage(offScr, 0, 0, null);

        //crean up the local graphics reference.
        offG.dispose();
    }

    private void clearGraphics(Graphics offG) {
        Color c = offG.getColor();
        offG.setColor(getBackground());
        offG.fillRect(0, 0, getSize().width, getSize().height);
        offG.setColor(c);
    }

    // Required component listener methods...

    public void componentResized(ComponentEvent e) {
        repaint();
    }

    public void componentMoved(ComponentEvent e) {
        repaint();
    }

    public void componentShown(ComponentEvent e) {
        repaint();
    }

    public void componentHidden(ComponentEvent e) {
        repaint();
    }

    public Dimension getPreferredSize() {
        return preferredSize;
    }

    public void setPreferredSize(Dimension dimension) {
        preferredSize = dimension;
    }
    public void setPreferredSize(int width, int height) {
        setPreferredSize(new Dimension(width, height));
    }

}