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

/**
 * A RandomArtPanel draws random pictures which might be taken to have
 * some vague resemblance to abstract art.  A new picture is produced every
 * four seconds.  There are three types of pictures:  random lines,
 * random circles, and random 3D rects.  The figures are drawn in
 * random colors on a background that is a random shade of gray.
 */
public class RandomArtPanel extends JPanel {
   
   /**
    * A RepaintAction object calls the repaint method of this panel each
    * time its actionPerformed() method is called.  An object of this
    * type is used as an action listener for a Timer that generates an
    * ActionEvent every four seconds.  The result is that the panel is
    * redrawn every four seconds.
    */
   private class RepaintAction implements ActionListener {
      public void actionPerformed(ActionEvent evt) {
         repaint();  // Call the repaint() method in the panel class.
      }
   }
   
   /**
    * The constructor creates a timer with a delay time of four seconds
    * (4000 milliseconds), and with a RepaintAction object as its
    * ActionListener.  It also starts the timer running.
    */
   public RandomArtPanel() {
      RepaintAction action = new RepaintAction();
      Timer timer = new Timer(4000, action);
      timer.start();
   }
   
   /**
    * The paintComponent() method fills the panel with a random shade of
    * gray and then draws one of three types of random "art".  The type
    * of art to be drawn is chosen at random.
    */
   public void paintComponent(Graphics g) {

      // Note:  Since the next three lines fill the entire panel with
      // gray, there is no need to call super.paintComponent(g), since
      // any drawing that it does will only be covered up anyway.
      
      Color randomGray = Color.getHSBColor( 1.0F, 0.0F, (float)Math.random() );
      g.setColor(randomGray);
      g.fillRect( 0, 0, getWidth(), getHeight() );
      
      int artType = (int)(3*Math.random());

      switch (artType) {
      case 0:
         for (int i = 0; i < 500; i++) {
            int x1 = (int)(getWidth() * Math.random());
            int y1 = (int)(getHeight() * Math.random());
            int x2 = (int)(getWidth() * Math.random());
            int y2 = (int)(getHeight() * Math.random());
            Color randomHue = Color.getHSBColor( (float)Math.random(), 1.0F, 1.0F);
            g.setColor(randomHue);
            g.drawLine(x1,y1,x2,y2);
         }
         break;
      case 1:
         for (int i = 0; i < 200; i++) {
            int centerX =  (int)(getWidth() * Math.random());
            int centerY = (int)(getHeight() * Math.random());
            Color randomHue = Color.getHSBColor( (float)Math.random(), 1.0F, 1.0F);
            g.setColor(randomHue);
            g.drawOval(centerX - 50, centerY - 50, 100, 100);
         }
         break;
      case 2:
         for (int i = 0; i < 25; i++) {
            int centerX =  (int)(getWidth() * Math.random());
            int centerY = (int)(getHeight() * Math.random());
            int size = 30 + (int)(170*Math.random());
            Color randomColor = new Color( (int)(256*Math.random()), 
                  (int)(256*Math.random()), (int)(256*Math.random()) );
            g.setColor(randomColor);
            g.fill3DRect(centerX - size/2, centerY - size/2, size, size, true);
         }
         break;
      }
      
   } // end paintComponent()

} // end class RandomArtPanel