Re: Concentric circles questions. For some reason, center is not on same dimension

digibooster@gmail.com wrote:


I think you need to examine the JavaDocs of the
methods you are using..

<sscce>
import javax.swing.*;
import java.awt.*;
import java.util.Random;

/* CirclePanel.java
Design and implement a program that draws 10 concentric circles of
random radius.
*/
class CirclePanel extends JPanel
{
        public CirclePanel()
        {
                setPreferredSize (new Dimension(300,300));
                setBackground (Color.white);
        }

        public void paintComponent(Graphics page)
        {
                super.paintComponent (page);
                int x = 0, y = 0;
                int diameter;
                page.setColor (Color.white);

                for (int count = 0; count <10; count++)
                {
                        Random generator = new Random();
                        diameter = generator.nextInt(150)+5;
                        page.setColor (Color.black);

                        /* x,y is not the center, it is the
                        co-ord of the upper left of a 'box'
                        that surround the oval */
                        page.drawOval (x, y, diameter, diameter);

                        int centerX = getWidth()/2;
                        int centerY = getHeight()/2;

                        page.setColor (Color.red);
                        page.drawOval (centerX-(diameter/2),
                            centerY-(diameter/2),
                            diameter,
                            diameter);
                }
        }

        public static void main (String[] args)
        {
                JFrame frame = new JFrame ("Concentric");
                frame.setDefaultCloseOperation(
                    JFrame.EXIT_ON_CLOSE);

                frame.getContentPane().add(new CirclePanel());

                frame.pack();
                frame.setVisible(true);
        }
}
</sscce>

Andrew T.