/*
* 1.1 version.
*/
import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;
/*
* This applet displays several images in a row. It prevents
* flashing by double buffering. However, it doesn't wait
* for the images to fully load before drawing them, which
* causes the weird effect of the animation appearing from
* the top down.
*/
public class ImageSequence extends Applet
implements Runnable {
int frameNumber = -1;
int delay;
Thread animatorThread;
boolean frozen = false;
Image images[];
Dimension offDimension;
Image offImage;
Graphics offGraphics;
public void init() {
String str;
int fps = 10;
//How many milliseconds between frames?
str = getParameter("fps");
try {
if (str != null) {
fps = Integer.parseInt(str);
}
} catch (Exception e) {}
delay = (fps > 0) ? (1000 / fps) : 100;
//Get the images.
images = new Image[10];
for (int i = 1; i <= 10; i++) {
images[i-1] = getImage(getCodeBase(),
"T"+i+".gif");
}
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
if (frozen) {
frozen = false;
start();
} else {
frozen = true;
//Instead of calling stop(), which destroys the
//backbuffer, just stop the animating thread.
animatorThread = null;
}
}
});
}
public void start() {
if (frozen) {
//Do nothing. The user has requested that we
//stop changing the image.
} else {
//Start animating!
if (animatorThread == null) {
animatorThread = new Thread(this);
}
animatorThread.start();
}
}
public void stop() {
//Stop the animating thread.
animatorThread = null;
//Get rid of the objects necessary for double buffering.
offGraphics = null;
offImage = null;
}
public void run() {
//Just to be nice, lower this thread's priority
//so it can't interfere with other processing going on.
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
//Remember the starting time.
long startTime = System.currentTimeMillis();
//Remember which thread we are.
Thread currentThread = Thread.currentThread();
//This is the animation loop.
while (currentThread == animatorThread) {
//Advance the animation frame.
frameNumber++;
//Display it.
repaint();
//Delay depending on how far we are behind.
try {
startTime += delay;
Thread.sleep(Math.max(0,
startTime-System.currentTimeMillis()));
} catch (InterruptedException e) {
break;
}
}
}
//Draw the current frame of animation.
public void paint(Graphics g) {
update(g);
}
public void update(Graphics g) {
Dimension d = getSize();
//Create the offscreen graphics context,
//if no good one exists.
if ( (offGraphics == null)
|| (d.width != offDimension.width)
|| (d.height != offDimension.height) ) {
offDimension = d;
offImage = createImage(d.width, d.height);
offGraphics = offImage.getGraphics();
}
//Erase the previous image.
offGraphics.setColor(getBackground());
offGraphics.fillRect(0, 0, d.width, d.height);
offGraphics.setColor(Color.black);
//Paint the frame into the image.
try {
offGraphics.drawImage(images[frameNumber%10],
0, 0, this);
} catch(ArrayIndexOutOfBoundsException e) {
//On rare occasions, this method can be called
//when frameNumber is still -1. Do nothing.
return;
}
//Paint the image onto the screen.
g.drawImage(offImage, 0, 0, this);
}
}
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