I am trying to replace a BufferedImage in my code with an animated gif

Question

Currently in my code I have a BufferedImage drawn like:

Graphics2D g2d = (Graphics2D) g;
g2d.transform(at); //at is an AffineTransform that just rotates the .gif
g2d.drawImage(sharkie, xCenter-5*radius, yCenter-3*radius, 10*radius, 6*radius, null);

I already have it fully functioning as a BufferedImage, but as expected it shows only the first frame. I was wondering if anyone knew of a way that is analogous to BufferedImage that works for animated gifs. I can't seem to get swing to work with the technique of adding it to a JButton. I also cannot figure out if there is a viable ImageObserver that would animate the .gif in the drawImage() call.

I am willing to try anything, but I am most interested in the possibility of making the draw call work with an ImageObserver as that would be only a small change.

Thanks all!

Answer 1

"I already have it fully functioning as a BufferedImage, but as expected it shows only the first frame"

This will happen when trying to read the image with ImageIO.read(...). If you read it with new ImageIcon(...).getImage(), you'll get the gif animation. See here.

"I also cannot figure out if there is a viable ImageObserver that would animate the .gif in the drawImage() call."

The ImageObserver is the component you are painting on. So instead of using drawImage(..., null), you should be using drawImage(..., this)

"I am willing to try anything, but I am most interested in the possibility of making the draw call work with an ImageObserver as that would be only a small change."

Combine the two points above and you got your answer.

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Give this code a test run. gif image taken from this answer

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class TestGif {

    public TestGif() {
        JFrame frame = new JFrame();
        frame.add(new GifPanel());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public class GifPanel extends JPanel {
        Image image;
        {
            try {
                image = new ImageIcon(new URL("http://i.stack.imgur.com/lKfdp.gif")).getImage();
            } catch (MalformedURLException ex) {
                Logger.getLogger(TestGif.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawImage(image, 0, 0, this);
        }
        @Override
        public Dimension getPreferredSize() {
            return image == null ? new Dimension(200, 200) 
                    : new Dimension(image.getWidth(this), image.getHeight(this));
        }
    }

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