import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;

public class RollBackground{
  public static void main(String args[]){
     JFrame frame=new JFrame("Roll Background");
     frame.setSize(600,600);
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     JCanvas canvas=new JCanvas();
     frame.add(canvas);
     frame.setVisible(true);
     //
     BufferedImage image=canvas.loadImage("res/oceano.gif");
     int iHeight=image.getHeight(); 
     int height=canvas.getHeight()-20;
     int width=canvas.getWidth()-20;
     BufferedImage tiles=canvas.tileImage(image,width,height+iHeight); 
     int j=0; 
     while(true){
       canvas.startBuffer();
       canvas.clear();
       canvas.setClip(10, 10, width, height);
       canvas.drawImage(tiles,10,10-j); 
       j++;;if(j>=iHeight)j=0;
       canvas.endBuffer();
       canvas.sleep(10);
     }
  }
}