Once again a boring question?

Question

i am trying to creat a about window such as when one clicks the about photoshop cs by going to the help menu and he gets a window with transparency.
I created a JLabel with an imageicon of gif having transparency and added it to the contentpane of JDialog. I also set the JLabel component to setOpaque(true) but it still shows a white background.
How can I fix it?

Answer 1

This should be in the Swing forum, right? Anyway, I think that you may have to
resort to calling native code to get a truly transparent dialog. The next best thing
to that would be to use Robot to take a screen capture and use that image
as your dialog's background. The is nearly as effective, if you make the window
not movable.
Here's a demo where I use the screen capture effect to make the window disolve.
Just cliick a few times on my ca r:-)
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.IOException;
import java.net.URL;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Fade extends JLabel {
    public static void main(String[] args) throws Exception {
        String urlPrefix = "http://www3.us.porsche.com/english/usa/carreragt/modelinformation/experience/desktop/bilder/icon";
        String urlSuffix = "_800x600.jpg";
        URL[] urls = new URL[4];
        for(int i=0; i<urls.length; ++i)
            urls[i] = new URL(urlPrefix + (i+1) + urlSuffix);
        BufferedImage[] images = getImages(urls);
        Robot robot = new Robot();
        images[3] = robot.createScreenCapture(new Rectangle(0,0,800,600));
        JFrame f = new JFrame("fade");
        f.setUndecorated(true);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new Fade(16, images));
        f.pack();
        f.setBounds(0,0,800,600);
        f.setVisible(true);
    public static BufferedImage convert(Image image) {
        int w=image.getWidth(null), h=image.getHeight(null);
        if (w <= 0)
            throw new IllegalArgumentException("Whoa, width is " + w);
        if (h <= 0)
            throw new IllegalArgumentException("Whoa, height is " + h);
        BufferedImage result = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = result.createGraphics();
        g.drawImage(image, 0, 0, null);
        g.dispose();
        return result;
    public static BufferedImage[] getImages(URL[] urls) throws IOException {
        BufferedImage[] images = new BufferedImage[urls.length];
        for(int i=0; i<urls.length; ++i)
            images[i] = convert(ImageIO.read(urls));
return images;
private int currentStage, stages, currentFrame;
int[] target;
int[][] sources, pixels;
public Fade(int stages, BufferedImage[] images) {
super(new ImageIcon(images[0]));
this.stages = stages;
currentStage = stages-1;
currentFrame = 1;
target = getData(images[0]);
sources = new int[images.length][];
sources[0] = (int[]) target.clone();
for(int i=1; i<images.length; ++i)
sources[i] = getData(images[i]);
int N = target.length;
Random rnd = new Random();
int[] rand = new int[N];
for(int j=0; j<N; ++j)
rand[j] = j;
int randUB = N;
int pixelsPerStage = N / currentStage;
int extras = N % currentStage;
pixels = new int[currentStage][];
for(int stage=0; stage<currentStage; ++stage) {
int[] row = pixels[stage] = new int[pixelsPerStage + (stage<extras?1:0)];
for(int j=0; j<row.length; ++j) {
int offset = rnd.nextInt(randUB);
row[j] = rand[offset];
rand[offset] = rand[--randUB];
class MouseTimer extends MouseAdapter implements ActionListener {
Timer timer = new Timer(50, this);
public void actionPerformed(ActionEvent evt) {
if (nextStage())
repaint();
else {
timer.stop();
nextFrame();
public void mousePressed(MouseEvent evt) {
timer.start();
addMouseListener(new MouseTimer());
static int[] getData(BufferedImage image) {
return ((DataBufferInt)(image.getRaster().getDataBuffer())).getData();
public void nextFrame() {
currentStage = stages-1;
currentFrame = (currentFrame+1)%sources.length;
public boolean nextStage() {
if (currentStage > 0) {
--currentStage;
int[] row = pixels[currentStage];
int[] source = sources[currentFrame];
for(int j=0; j<row.length; ++j)
target[row[j]] = source[row[j]];
return true;
} else
return false;