Using JFrame to display an image through a loop

Question

I have a recursive loop that performs calculations on an image and want to display the progress of the image through each iteration.

This is what I have:

static JFrame colFrame = new JFrame();
main() {}

loop() {

        JLabel label = null;
        ImageIcon colIcon = new ImageIcon(blockImg);
        label = new JLabel(colIcon);
        colFrame.getContentPane().add(label);
        colFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // close canvas once the window is closed
        colFrame.pack();
        colFrame.setVisible(true);

}

Does anyone know how to change my code so that it will display the image through each iteration?

Answer 1

Use a Swing Timer to schedule the animation of changing the image.

Here is my simple example that changes the text of the label every second:

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

public class TimerTime extends JPanel implements ActionListener
{
    private JLabel timeLabel;
    private int count = 0;

    public TimerTime()
    {
        timeLabel = new JLabel( new Date().toString() );
        add( timeLabel );

        Timer timer = new Timer(1000, this);
        timer.setInitialDelay(1);
        timer.start();
    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
        //System.out.println(e.getSource());
        timeLabel.setText( new Date().toString() );
//      timeLabel.setText( String.valueOf(System.currentTimeMillis() ) );
        count++;
        System.out.println(count);

        if (count == 10)
        {
            Timer timer = (Timer)e.getSource();
            timer.stop();
        }
    }

    private static void createAndShowUI()
    {
        JFrame frame = new JFrame("TimerTime");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new TimerTime() );
        frame.setLocationByPlatform( true );
        frame.pack();
        frame.setVisible( true );
    }

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

In your case you would want to change the Icon (not create a new label).

Answer 2

Because your algorithm is recursive, invoke it in the doInBackground() implementation of a SwingWorker . At each level, publish() a BufferedImage representing the current state, and process() it using label.setIcon() . An example that generates a BufferedImage is shown here , and a related example that generates a TexturePaint is shown here .