// ImageAnimation.java: Display a sequence of images
package chapter16;

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

public class ImageAnimation extends JApplet implements ActionListener
{
  private Image imageToDisplay;
  protected Image imageArray[]; // Hold images
  protected int numOfImages = 52, // Total number of images
                currentImageIndex = 0, // Current image subscript
                sleepTime = 100; // Milliseconds to sleep
  protected int direction = 1; // Image rotating direction

  // Image display panel
  protected PlayImage imagePanel = new PlayImage();

  // Text field for receiving speed
  protected JTextField jtfSpeed = new JTextField(5);

  // Button for reversing direction
  JButton jbtReverse = new JButton("Reverse");

  /**Initialize the applet*/
  public void init()
  {
    // Load the image, the image files are named
    // L1 - L52 in Images directory
    imageArray = new Image[numOfImages];
    for (int i=0; i<imageArray.length; i++ )
    {
      imageArray[i] = getImage(getDocumentBase(),
        "image/L" + (i+1) + ".gif" );
    }

    // Panel p to hold animation control
    JPanel p = new JPanel();
    p.setLayout(new BorderLayout());
    p.add(new JLabel("Animation speed in millisecond"),
      BorderLayout.WEST);
    p.add(jtfSpeed, BorderLayout.CENTER);
    p.add(jbtReverse, BorderLayout.EAST);

    // Add the image panel and p to the applet
    getContentPane().add(imagePanel, BorderLayout.CENTER);
    getContentPane().add(p, BorderLayout.SOUTH);

    // Register listener
    jtfSpeed.addActionListener(this);
    jbtReverse.addActionListener(this);
  }

  /**Handle ActionEvent*/
  public void actionPerformed(ActionEvent e)
  {
    if (e.getSource() == jtfSpeed)
    {
      sleepTime = Integer.parseInt(jtfSpeed.getText());
      imagePanel.setSpeed(sleepTime);
    }
    else if (e.getSource() == jbtReverse)
    {
      direction = -direction;
    }
  }

  /**Override the start method in the Applet class*/
  public void start()
  {
    imagePanel.start();
  }

  /**Override the stop method in the Applet class*/
  public void stop()
  {
    imagePanel.stop();
  }

  protected class PlayImage extends JPanel implements ActionListener
  {
    protected Timer timer;

    /**Constructor*/
    public PlayImage()
    {
      // Start with the first image
      currentImageIndex = 0;

      // Set line border on the panel
      setBorder(new LineBorder(Color.red, 1));

      // Create a timer with delay 1000 ms and listener Clock
      timer = new Timer(1000, this);

      // Start the timer
      timer.start();
    }

    public void setSpeed(int sleepTime)
    {
      timer.setDelay(sleepTime);
    }

    public void start()
    {
      timer.start();
    }

    public void stop()
    {
      timer.stop();
    }

    // Choose a new image to display
    public void actionPerformed(ActionEvent e)
    {
      imageToDisplay =
        imageArray[currentImageIndex%numOfImages];

      // Make sure currentImageIndex is nonnegative
      if (currentImageIndex == 0) currentImageIndex = numOfImages;
      currentImageIndex = currentImageIndex + direction;
      repaint();
    }


    // Display an image
    public void paintComponent(Graphics g)
    {
      super.paintComponent(g);

      if (imageToDisplay != null)
      {
        g.drawImage(imageToDisplay, 0, 0, getSize().width,
          getSize().height, this);
      }
    }
  }
}