import java.awt.*;
import java.awt.event.*;

class LightContainer extends Container
{


  private Image background;
  protected OffBuffer buffer = new OffBuffer(this);

  public LightContainer(){ this(null); }
  public LightContainer(Image background)
    {
       setLayout (null);
       if (background != null)
         this.background  = background;


       /* guard against component resizing */
       addComponentListener(new ComponentAdapter(){
            public void componentResized(ComponentEvent e){
                  buffer.update();
                  repaint();
                }

        });
    }

  public void update(Graphics g)
    {
       paint(g);
    }
  public void paint (Graphics g)
    {
       if (damaged(g))
          buffer.blitWork(g.getClipBounds());
       else
        {
            Graphics work = buffer.getWorkGraphics();
            Dimension size = getSize();

            paintBackground();
            work.setClip (0,0,size.width, size.height);
            super.paint(work);
            buffer.blitWork();
            work.dispose();
        }

    }

  public void paintComponent (Component comp)
    {
      paintComponent (comp, true);
    }
  public void eraseComponent (Component comp)
    {
      eraseComponent (comp, true);
    }
  public void paintComponent (Component comp, boolean update)
    {
       Graphics work = buffer.getWorkGraphics();
       Rectangle bounds = comp.getBounds();
       Graphics compG;

       compG = work.create(bounds.x, bounds.y, bounds.width,
                    bounds.height);

       comp.paint (compG);
       if (update)
         buffer.blitWork(bounds);
       work.dispose();
    }

  public void eraseComponent (Component comp, boolean update)
    {
       Rectangle bounds = comp.getBounds();
       buffer.blitBack(bounds);
       paintOverlap(comp);
       if (update)
            buffer.blitWork(bounds);

    }

  public void paintOverlap(Component comp)
    {
       Graphics work = buffer.getWorkGraphics();
       Rectangle bounds = comp.getBounds();
       work.setClip (bounds);
       comp.setVisible(false);
       super.paint(work);
       comp.setVisible(true);
       work.dispose();
    }

  public void moveComponent (Component comp, Point newLoc)
    {

       Rectangle oldBounds = comp.getBounds();
       eraseComponent(comp, false);
       comp.setLocation (newLoc);
       paintComponent(comp, false);

       buffer.blitWork(oldBounds.union(comp.getBounds()));


    }
  public boolean damaged(Graphics g)
    {
       Rectangle clip = g.getClipBounds();
       Dimension size = getSize();
       return ( (clip.x != 0 || clip.y != 0) ||
                (clip.width < size.width ||
                 clip.height < size.height));
    }

  protected void paintBackground(){ paintBackground( (Rectangle) null);}
  protected void paintBackground(Rectangle clip)
    {
       Graphics g = buffer.getBackGraphics();
       if (clip!= null)
        g.setClip(clip);
       paintBackground(g);
       buffer.blitBack();
       g.dispose();
    }
  protected void paintBackground( Graphics g )
    {
       if (background != null)
        g.drawImage (background, 0,0, this);
        for (int w=0; w<size().width; w+=12)
                {
                  for (int h=0; h<size().height; h+=12)
                    {
                      g.setColor(Color.white);
                      g.drawLine(w,h,w+1,h);
                      g.drawLine(w+1,h,w+5,h+4);
                      g.drawLine(w+8,h+10,w+12,h+6);
                      g.drawLine(w+12,h+6,w+13,h+6);
                      g.setColor(Color.darkGray);
                      g.drawLine(w,h+2,w+5,h+7);
                      g.drawLine(w+5,h+7,w+6,h+7);
                      g.drawLine(w+9,h+12,w+13,h+8);
                    }
                  }

    }


}