Marquee effect in Java Swing

Question

How can I implement Marquee effect in Java Swing

Answer 1

A java swing program to marquee a text

Answer 2

I've just Googled for it and found this link. I ran the code and it appears to do what you want.

Answer 3

Basic answer is you draw your text / graphic into a bitmap and then implement a component that paints the bitmap offset by some amount. Usually marquees / tickers scroll left so the offset increases which means the bitmap is painted at -offset. Your component runs a timer that fires periodically, incrementing the offset and invalidating itself so it repaints.

Things like wrapping are a little more complex to deal with but fairly straightforward. If the offset exceeds the bitmap width you reset it back to 0. If the offset + component width > bitmap width you paint the remainder of the component starting from the beginning of the bitmap.

The key to a decent ticker is to make the scrolling as smooth and as flicker free as possible. Therefore it may be necessary to consider double buffering the result, first painting the scrolling bit into a bitmap and then rendering that in one go rather than painting straight into the screen.

Answer 4

Here is some code that I threw together to get you started. I normally would take the ActionListener code and put that in some sort of MarqueeController class to keep this logic separate from the panel, but that's a different question about organizing the MVC architecture, and in a simple enough class like this it may not be so important.

There are also various animation libraries that would help you do this, but I don't normally like to include libraries into projects only to solve one problem like this.

public class MarqueePanel extends JPanel {
  private JLabel textLabel;
  private int panelLocation;
  private ActionListener taskPerformer;
  private boolean isRunning = false;

  public static final int FRAMES_PER_SECOND = 24;
  public static final int MOVEMENT_PER_FRAME = 5;

  /**
   * Class constructor creates a marquee panel.
   */

  public MarqueePanel() {
    this.setLayout(null);
    this.textLabel = new JLabel("Scrolling Text Here");
    this.panelLocation = 0;
    this.taskPerformer = new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
        MarqueePanel.this.tickAnimation();
      }
    }
  }

  /**
   * Starts the animation.
   */

  public void start() {
    this.isRunning = true;
    this.tickAnimation();
  }

  /**
   * Stops the animation.
   */

  public void stop() {
    this.isRunning = false;
  }

  /**
   * Moves the label one frame to the left.  If it's out of display range, move it back
   * to the right, out of display range.
   */

  private void tickAnimation() {
    this.panelLocation -= MarqueePanel.MOVEMENT_PER_FRAME;
    if (this.panelLocation < this.textLabel.getWidth())
      this.panelLocaton = this.getWidth();
    this.textLabel.setLocation(this.panelLocation, 0);
    this.repaint();
    if (this.isRunning) {
      Timer t = new Timer(1000 / MarqueePanel.FRAMES_PER_SECOND, this.taskPerformer);
      t.setRepeats(false);
      t.start();
    }
  }
}

Answer 5

Here's an example using javax.swing.Timer.

import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

/** @see http://stackoverflow.com/questions/3617326 */
public class MarqueeTest {

    private void display() {
        JFrame f = new JFrame("MarqueeTest");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        String s = "Tomorrow, and tomorrow, and tomorrow, "
        + "creeps in this petty pace from day to day, "
        + "to the last syllable of recorded time; ... "
        + "It is a tale told by an idiot, full of "
        + "sound and fury signifying nothing.";
        MarqueePanel mp = new MarqueePanel(s, 32);
        f.add(mp);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
        mp.start();
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new MarqueeTest().display();
            }
        });
    }
}

/** Side-scroll n characters of s. */
class MarqueePanel extends JPanel implements ActionListener {

    private static final int RATE = 12;
    private final Timer timer = new Timer(1000 / RATE, this);
    private final JLabel label = new JLabel();
    private final String s;
    private final int n;
    private int index;

    public MarqueePanel(String s, int n) {
        if (s == null || n < 1) {
            throw new IllegalArgumentException("Null string or n < 1");
        }
        StringBuilder sb = new StringBuilder(n);
        for (int i = 0; i < n; i++) {
            sb.append(' ');
        }
        this.s = sb + s + sb;
        this.n = n;
        label.setFont(new Font("Serif", Font.ITALIC, 36));
        label.setText(sb.toString());
        this.add(label);
    }

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

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

    @Override
    public void actionPerformed(ActionEvent e) {
        index++;
        if (index > s.length() - n) {
            index = 0;
        }
        label.setText(s.substring(index, index + n));
    }
}