Rendering...Can anyone help???

Question

I have 2 classes for rendering images. When i run the application, the images kept flashing, may i know how could i actually have 1 image appearing instead of many images flashing? In other words, i would like in a way similar to mosaic rendering process...Thanks alot
import javax.swing.ImageIcon;
import javax.swing.JApplet;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedInputStream;
* TumbleItem.java requires these files:
* SwingWorker.java
* all the images in the images/tumble directory
* (or, if specified in the applet tag, another directory [dir]
* with images named T1.gif ... Tx.gif, where x is the total
* number of images [nimgs])
* the appropriate code to specify that the applet be executed,
* such as the HTML code in TumbleItem.html or TumbleItem.atag,
* or the JNLP code in TumbleItem.jnlp
public class TumbleItem extends JApplet
implements ActionListener {
int loopslot = -1; //the current frame number
String dir; //the directory relative to the codebase
//from which the images are loaded
javax.swing.Timer timer;
//the timer animating the images
int pause; //the length of the pause between revs
int offset; //how much to offset between loops
int off; //the current offset
int speed; //animation speed
int nimgs; //number of images to animate
int width; //width of the applet's content pane
Animator animator; //the applet's content pane
ImageIcon imgs[]; //the images
int maxWidth; //width of widest image
boolean finishedLoading = false;
JLabel statusLabel;
static Color[] labelColor = { Color.black, Color.black,
Color.black, Color.black,
Color.black, Color.black,
Color.white, Color.white,
Color.white, Color.white };
//Called by init.
protected void loadAppletParameters() {
//Get the applet parameters.
String at = getParameter("img");
dir = (at != null) ? at : "images/tumble";
at = getParameter("pause");
pause = (at != null) ? Integer.valueOf(at).intValue() : 1900;
at = getParameter("offset");
offset = (at != null) ? Integer.valueOf(at).intValue() : 0;
at = getParameter("speed");
speed = (at != null) ? (1000 / Integer.valueOf(at).intValue()) : 100;
at = getParameter("nimgs");
nimgs = (at != null) ? Integer.valueOf(at).intValue() : 16;
at = getParameter("maxwidth");
maxWidth = (at != null) ? Integer.valueOf(at).intValue() : 0;
* Create the GUI. For thread safety, this method should
* be invoked from the event-dispatching thread.
private void createGUI() {
//Animate from right to left if offset is negative.
width = getSize().width;
if (offset < 0) {
off = width - maxWidth;
//Custom component to draw the current image
//at a particular offset.
animator = new Animator();
animator.setOpaque(true);
animator.setBackground(Color.white);
setContentPane(animator);
//Put a "Loading Images..." label in the middle of
//the content pane. To center the label's text in
//the applet, put it in the center part of a
//BorderLayout-controlled container, and center-align
//the label's text.
statusLabel = new JLabel("Loading Images...",
JLabel.CENTER);
statusLabel.setForeground(labelColor[0]);
animator.add(statusLabel, BorderLayout.CENTER);
//Called when this applet is loaded into the browser.
public void init() {
loadAppletParameters();
//Execute a job on the event-dispatching thread:
//creating this applet's GUI.
try {
javax.swing.SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
createGUI();
} catch (Exception e) {
System.err.println("createGUI didn't successfully complete");
//Set up the timer that will perform the animation.
timer = new javax.swing.Timer(speed, this);
timer.setInitialDelay(pause);
timer.setCoalesce(false);
timer.start(); //Start the animation.
//Loading the images can take quite a while, so to
//avoid staying in init() (and thus not being able
//to show the "Loading Images..." label) we'll
//load the images in a SwingWorker thread.
imgs = new ImageIcon[nimgs];
final SwingWorker worker = new SwingWorker() {
public Object construct() {
//Images are numbered 1 to nimgs,
//but fill array from 0 to nimgs-1.
for (int i = 0; i < nimgs; i++) {
imgs = loadImage(i+1);
finishedLoading = true;
return imgs;
//Executes in the event-dispatching thread.
public void finished() {
//Remove the "Loading images" label.
animator.removeAll();
loopslot = -1;
worker.start();
//The component that actually presents the GUI.
public class Animator extends JPanel {
public Animator() {
super(new BorderLayout());
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (finishedLoading &&
(loopslot > -1) && (loopslot < nimgs)) {
if (imgs != null && imgs[loopslot] != null) {
imgs[loopslot].paintIcon(this, g, off, 0);
//Update the the loopslot (frame number) and the offset.
//If it's the last frame, restart the timer to get a long
//pause between loops.
public void actionPerformed(ActionEvent e) {
loopslot++;
if (!finishedLoading) {
int colorIndex = loopslot % labelColor.length;
try {
statusLabel.setForeground(labelColor[colorIndex]);
} catch (NullPointerException exc) {}
return;
if (loopslot >= nimgs) {
loopslot = 0;
off += offset;
if (off < 0) {
off = width - maxWidth;
} else if (off + maxWidth > width) {
off = 0;
animator.repaint();
if (loopslot == nimgs - 1) {
timer.restart();
//Called to start the applet's execution.
public void start() {
if (finishedLoading && (nimgs > 1)) {
timer.restart();
//Called to stop (temporarily or permanently) the applet's execution.
public void stop() {
timer.stop();
protected ImageIcon loadImage(int imageNum) {
String path = dir + "/Image" + imageNum + ".jpg";
int MAX_IMAGE_SIZE = 2400; //Change this to the size of
//your biggest image, in bytes.
int count = 0;
BufferedInputStream imgStream = new BufferedInputStream(
this.getClass().getResourceAsStream(path));
if (imgStream != null) {
byte buf[] = new byte[MAX_IMAGE_SIZE];
try {
count = imgStream.read(buf);
imgStream.close();
} catch (java.io.IOException ioe) {
System.err.println("Couldn't read stream from file: " + path);
return null;
if (count <= 0) {
System.err.println("Empty file: " + path);
return null;
return new ImageIcon(Toolkit.getDefaultToolkit().createImage(buf));
} else {
System.err.println("Couldn't find file: " + path);
return null;
public String getAppletInfo() {
return "Title: TumbleItem v1.2, 23 Jul 1997\n"
+ "Author: Interactive Mosaic\n"
+ "A simple Item class to play an image loop.";
public String[][] getParameterInfo() {
String[][] info = {
{"img", "string", "the directory containing the images to loop"},
{"pause", "int", "pause between complete loops; default is 3900"},
{"offset", "int", "offset of each image to simulate left (-) or "
+ "right (+) motion; default is 0 (no motion)"},
{"speed", "int", "the speed at which the frames are looped; "
+ "default is 100"},
{"nimgs", "int", "the number of images to be looped; default is 16"},
{"maxwidth", "int", "the maximum width of any image in the loop; "
+ "default is 0"}
return info;
import javax.swing.SwingUtilities;
public abstract class SwingWorker {
private Object value; // see getValue(), setValue()
* Class to maintain reference to current worker thread
* under separate synchronization control.
private static class ThreadVar {
private Thread thread;
ThreadVar(Thread t) { thread = t; }
synchronized Thread get() { return thread; }
synchronized void clear() { thread = null; }
private ThreadVar threadVar;
* Get the value produced by the worker thread, or null if it
* hasn't been constructed yet.
protected synchronized Object getValue() {
return value;
* Set the value produced by worker thread
private synchronized void setValue(Object x) {
value = x;
* Compute the value to be returned by the <code>get</code> method.
public abstract Object construct();
* Called on the event dispatching thread (not on the worker thread)
* after the <code>construct</code> method has returned.
public void finished() {
* A new method that interrupts the worker thread. Call this method
* to force the worker to stop what it's doing.
public void interrupt() {
Thread t = threadVar.get();
if (t != null) {
t.interrupt();
threadVar.clear();
public Object get() {
while (true) {
Thread t = threadVar.get();
if (t == null) {
return getValue();
try {
t.join();
catch (InterruptedException e) {
Thread.currentThread().interrupt(); // propagate
return null;
* Start a thread that will call the <code>construct</code> method
* and then exit.
public SwingWorker() {
final Runnable doFinished = new Runnable() {
public void run() { finished(); }
Runnable doConstruct = new Runnable() {
public void run() {
try {
setValue(construct());
finally {
threadVar.clear();
SwingUtilities.invokeLater(doFinished);
Thread t = new Thread(doConstruct);
threadVar = new ThreadVar(t);
* Start the worker thread.
public void start() {
Thread t = threadVar.get();
if (t != null) {
t.start();
}

Answer 1

Nobody pays any attention to those boundries ...
indeed many feel - and with good reason IMO - that
the response time is better on THIS forum.I don't agree. The Swing forum is followed by several
people who are very competent to answer Swing
questions. Questions posted there usually receive
good answers. Whereas this forum -- sure, people
answer questions here too. But it is also populated
by trolls and buffoons. And by people who don't have
the intelligence to figure out where a question
should be posted.
There are obvious reasons for having thirty forums
instead of one. I'm sure you can figure them out
without my help. So given that there should be more
than one forum, it follows that people should post in
the correct forum.I better quit while I can still stand, huh ;o)
Look I'll say it again ... I was not and am not suggesting that the camickr's point of view was wrong. I only questioned the weight that he appeared to be putting on it by outspokenly stating that swing questions ought to be posted to the swing forum only.
There are, as you state, a lot of other more specific forums; there are AWT forums and JDBC forums, etc., but I can't remember the last time someone posted that AWT, JDBC, or whatever threads ought ONLY be posted to their respective forums. In actual fact, in many/most cases they probably should be.
I had started a thread on - I think it was the AWT or some other forum - and found the response was not nearly so quick as it is on this forum. I'd noticed at least once that another well respected forum regular - not unlile yourself - did similarly.
My main point was - and at this point I am sorry that I even mentioned it I think - there alot of other issues that IMO - I image from what you wrote you don't agree, but in my opinion, take precedence.
Have a great weekend, and best regards,
~Bill