import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;

import java.awt.Toolkit;
import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Board extends JPanel 
    implements ActionListener {

    private final int B_WIDTH = 350;
    private final int B_HEIGHT = 350;
    private final int INITIAL_X = -40;
    private final int INITIAL_Y = -40;
    private final int DELAY = 25;
    
    private Image star;
    private Timer timer;
    private int x, y;

    public Board() {
                
        loadImage();
        initBoard();        
    }
    
    private void loadImage() {
        
        ImageIcon ii = new ImageIcon("star.png");
        star = ii.getImage();        
    }
    
    private void initBoard() {
        
        setBackground(Color.BLACK);
        setPreferredSize(new Dimension(B_WIDTH, B_HEIGHT));

        setDoubleBuffered(true);

        x = INITIAL_X;
        y = INITIAL_Y;
        
        timer = new Timer(DELAY, this);
        timer.start();
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        drawStar(g);
    }
    
    private void drawStar(Graphics g) {
        
        Graphics2D g2d = (Graphics2D) g;
        g2d.drawImage(star, x, y, this);
        Toolkit.getDefaultToolkit().sync();
        g.dispose();        
    }

    @Override
    public void actionPerformed(ActionEvent e) {
 
        x += 1;
        y += 1;

        if (y > B_HEIGHT) {
            
            y = INITIAL_Y;
            x = INITIAL_X;
        }
        
        repaint();  
    }
}