import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;

public class Test74 extends JPanel {

    Ellipse2D.Double e = new Ellipse2D.Double(210, 100, 30, 30);

    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setPaint(Color.red);
        g2.fill(e);

        Point2D.Double pc = new Point2D.Double(210, 300);
        Point2D.Double p = new Point2D.Double(210 + 15, 100 + 15);
        for(int i = 1; i<8; i++) {
            p = getPoint(pc, p, Math.PI/4);
            g2.fill(new Ellipse2D.Double(p.x - 15, p.y - 15, 30, 30));
        }
    }
    
    //得到p围绕pc旋转r(弧度)后的点
    public Point2D.Double getPoint(Point2D.Double pc, Point2D.Double p,
            double r) {
        double a = Math.atan2(pc.y - p.y, p.x - pc.x);
        double raduis = pc.distance(p);
        Point2D.Double result = new Point2D.Double();
        result.x = pc.x + raduis * Math.cos(a + r);
        result.y = pc.y - raduis * Math.sin(a + r);
        return result;
    }

    public static void main(String args[]) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new Test74());
        frame.setSize(500, 600);
        frame.setVisible(true);
    }
}