Re: Fading effect

Knute Johnson <>
Thu, 19 Jul 2007 11:31:41 -0700
lando wrote:

Knute Johnson ha scritto:

lando wrote:

How can be obtained the grate effects as in this applet >>>> ?

The way to do that is with AlphaComposite as Andrew Thompson said. It
is actually fairly simple to do the drawing. The complicated part is
the logic to flip through the images. If you don't like my images,
specify some of your own. They might not have anything different on
them depending on when you try this. They come from one of my
webcams. You can play with the timing to get the transitions to
happen as you like them.

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import javax.swing.*;

public class Fader extends JPanel implements Runnable {
    final BufferedImage[] images = new BufferedImage[6];
    volatile BufferedImage first,next;
    volatile AlphaComposite comp1 =
    volatile AlphaComposite comp2 =

    public Fader() {
        try {
            for (int i=0; i<images.length; i++)
                images[i] =
// new File(Integer.toString(i+1) + "0_min_ago.jpg"));
                 new URL("" +
                  Integer.toString(i+1) + "0_min_ago.jpg"));
        } catch (IOException ioe) {
        setPreferredSize(new Dimension(

    public void run() {
        while (true) {
            for (int i=0; i<images.length; i++) {
                first = images[i];
                if (i < images.length - 1)
                    next = images[i+1];
                    next = images[0];
                for (int j=0; j<60; j++) {
                    comp1 = AlphaComposite.getInstance(
                     AlphaComposite.SRC_OVER,1.0f / (j + 1));
                    comp2 = AlphaComposite.getInstance(
                     AlphaComposite.SRC_OVER,(j + 1) / 60.0f);
                    try {
                    } catch (InterruptedException ie) { }
                try {
                } catch (InterruptedException ie) { }

    public void paintComponent(Graphics g2D) {
        Graphics2D g = (Graphics2D)g2D;

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            public void run() {
                JFrame frame = new JFrame();
                Fader fader = new Fader();
                new Thread(fader).start();

Thanks a lot for your code.

I had the code from

that uses MemoryImageSource Class .....and now seems more complex....

Only the applet version has problems about an " access denied "...though
the images files are in the same folder of the .class file (this has
allowed to work the application version...)

Thanks again.

Applets generally can't read files. Applets can get files from their
own jar or from a socket connection to the same server that serves the


Knute Johnson
email s/nospam/knute/

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