Help needed in rendering images...ThAnkS

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[i] = 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();
* Return the value created by the <code>construct</code> method.
* Returns null if either the constructing thread or the current
* thread was interrupted before a value was produced.
* @return the value created by the <code>construct</code> method
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

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[i] = 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();
* Return the value created by the <code>construct</code> method.
* Returns null if either the constructing thread or the current
* thread was interrupted before a value was produced.
* @return the value created by the <code>construct</code> method
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();
}