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

public class Screen extends Panel{

  Image offimage;
  Graphics offgraphics;
  Dimension offdimension;
  Rectangle r = null;

  public Screen(MouseListener L, MouseMotionListener ML) {
    addMouseListener(L);
    addMouseMotionListener(ML);
  }

  public void paint(Graphics g) {
    Dimension d = getSize();
    
    if ((offgraphics == null) || 
	(offdimension.width != d.width) ||
	(offdimension.height != d.height)) {
      p("initialized graphics");
      setForeground(Color.black);
      setBackground(Color.white);
      offimage = createImage(d.width, d.height);
      offgraphics = offimage.getGraphics();
      offdimension = d;
      r = new Rectangle(d);
    }
    g.drawImage(offimage, 0, 0, this);
    //    p("repaint");
  }

  public void update(Graphics g){
    paint(g);
  }

  public void blank() {
    offgraphics.clearRect(0, 0, r.width, r.height);
  }

  public void clearImage(Image i, int x, int y) {
    int h = i.getHeight(this);
    int w = i.getWidth(this);
    offgraphics.clearRect(x, y, x+w, y+h);
  } 

  public void showImage(Image i, int x, int y) {
    offgraphics.drawImage(i, x, y, this);
  }

  public void drawHoriz(int y) {
    offgraphics.drawLine(0, y, r.width, y);
  }

  private void p(String s) {
    System.out.println(s);
  }
  
  private void p(Exception e) {
    System.out.println(e);
  }

}