import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

/**
Fyller en del av frame-vinduet med fylte sirkler,
én om gangen med en liten pause mellom hver.
*/
public class FillDemo extends JFrame implements ActionListener {
    public static final int WIDTH = 300;
    public static final int HEIGHT = 200;
    public static final int FILL_WIDTH = 300;
    public static final int FILL_HEIGHT = 100;
    public static final int CIRCLE_SIZE = 10;
    public static final int PAUSE = 100; //millisekunder
    private JButton startButton;
    private JButton avsluttButton;
	
    private JPanel box;

    public static void main(String[] args) {
        FillDemo gui = new FillDemo( );
        gui.setVisible(true);
    }

    public FillDemo( ) {
        setSize(WIDTH, HEIGHT);
        setTitle("FillDemo");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setLayout(new BorderLayout( ));

        box = new JPanel( );
        add(box, BorderLayout.CENTER);

        JPanel buttonPanel = new JPanel( );
        buttonPanel.setLayout(new FlowLayout( ));
        startButton = new JButton("Start");
        startButton.addActionListener(this);
        buttonPanel.add(startButton);
        avsluttButton = new JButton("Avslutt");
        avsluttButton.addActionListener(this);
        buttonPanel.add(avsluttButton);
        add(buttonPanel, BorderLayout.SOUTH);
    }

    public void actionPerformed(ActionEvent e) {
    	if (e.getSource() == avsluttButton)
    		System.exit(0);
    	else
        	fill( );
    }

    public void fill( ) {
        Graphics g = box.getGraphics( );

        for (int y = 0; y < FILL_HEIGHT; y = y + CIRCLE_SIZE)
            for (int x = 0; x < FILL_WIDTH; x = x + CIRCLE_SIZE) {
                g.fillOval(x, y, CIRCLE_SIZE, CIRCLE_SIZE);
                doNothing(PAUSE);
            }
    }

    public void doNothing(int milliseconds) {
        try {
            Thread.sleep(milliseconds);
        }
        catch(InterruptedException e) {
            System.out.println("Unexpected interrupt");
            System.exit(0);
        }
    }
}