Graphics help please

I've got some code below, in its early stages - my ultimate goal is to
be able to render pixel graphics to the screen, but I don't want to
render an entire image and then display it. I'd prefer to have it
shown as it draws, so that I can see the activity (for the time
being).
At a later stage I may want to render a chunk to the buffer and then
display it in one go (doublebuffering maybe).

How do I get it to render after the initial display of the applet? I
tried adding a loop where I draw the circle in the for loop, but it
only displays after it's finished. I assume it's because the loop is
running after the initial paint, but before the display is finally
rendered to the screen. What I need to know is how to run it outside
of this loop, and being a total java newbie, I can't see how to do it.

Suggestions as to how to rearrange this code would be greatly
appreciated. It took me long enough to find out how to render single
pixels directly without tons of code (lines with the same start and
end coordinates are not suitable for my ultimate goal).

import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.lang.Math.*;

public class Pixelgraphics extends JFrame
{
    public static void main(String [] args)
    {
        new Pixelgraphics();
    }
    
    public Pixelgraphics()
    {
        this.setSize(300,300);
        this.setTitle("Pixel Graphics");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        this.add(new PaintSurface(), BorderLayout.CENTER);
                this.setVisible(true);
    }
    
    private class PaintSurface extends JComponent
    {
        public void paint(Graphics g)
        {
            //drawing code goes here
            Graphics2D g2 = (Graphics2D)g;
            
            BufferedImage buf = g2.getDeviceConfiguration
().createCompatibleImage(300, 300, Transparency.OPAQUE);
            
            for(int i = 0; i <360; i++)
            {
                int x = 150 + (int)(20 * Math.sin(i));
                int y = 150 + (int)(20 * Math.cos(i));
                buf.setRGB(x, y, new Color(255,255, 255).getRGB());
                g2.drawImage(buf,0,0,null);

// I want to be able to pause here to see the screen as it draws
            }
            
        }
    }
}