swt custom widget support gif animation

AnimatedGif.java

// copy from: https://stackoverflow.com/questions/13479833/java-swt-animated-gif
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.ImageLoader;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;

public class AnimatedGif extends Canvas {

    private final ImageLoader loader = new ImageLoader();
    private int img = 0;
    private volatile boolean animating = false;
    private Thread animateThread;

    public AnimatedGif(Composite parent, int style) {
        super(parent, style);
    }

    public void load (InputStream resource) {
        loader.load(resource);
    }

    public void load (String path) throws IOException {
        loader.load(new FileInputStream(new File(path)));
    }

    public void animate() {
        if (animateThread == null) {
            animateThread = createThread();
            animateThread.setDaemon(true);
        }

        if (animateThread.isAlive())
            return;

        animateThread.start();
    }

    public void stop() {
        animating = false;
        if (animateThread != null)
            try {
                animateThread.join();
                animateThread = null;
            } catch (InterruptedException e) {
                // do nothing
            }
    }

    private Thread createThread() {
        return new Thread() {
            long currentTime = System.currentTimeMillis();
            final Display display = getParent().getDisplay();
            public void run() {
                animating = true;
                while(animating) {
                    img = (img == loader.data.length-1) ? 0 : img + 1;
                    int delayTime = Math.max(50, 10*loader.data[img].delayTime);
                    long now = System.currentTimeMillis();
                    long ms = Math.max(currentTime + delayTime - now, 5);
                    currentTime += delayTime;
                    try {
                        Thread.sleep(ms);
                    } catch(Exception e) {
                        return;
                    }

                    if (!display.isDisposed())
                        display.asyncExec(new Runnable() {

                            @Override
                            public void run() {
                                if (!AnimatedGif.this.isDisposed()) {
                                    ImageData nextFrameData = loader.data[img];
                                    Image frameImage = new Image(display, nextFrameData);
                                    new GC(AnimatedGif.this).drawImage(frameImage, nextFrameData.x, nextFrameData.y);
                                    frameImage.dispose();
                                }
                            }
                        });
                }

                Display.getDefault().asyncExec(new Runnable() {
                    @Override
                    public void run() {
                        if (!AnimatedGif.this.isDisposed()) {
                            new GC(AnimatedGif.this).fillRectangle(
                                    0,
                                    0,
                                    getBounds().width,
                                    getBounds().height);
                        }
                    }
                });
            }
        };
    }

}