FileDocCategorySizeDatePackage
ImageSequence.javaAPI DocExample4350Tue Dec 12 18:58:52 GMT 2000None

ImageSequence

public class ImageSequence extends Applet implements Runnable

Fields Summary
int
frameNumber
int
delay
Thread
animatorThread
boolean
frozen
Image[]
images
Dimension
offDimension
Image
offImage
Graphics
offGraphics
Constructors Summary
Methods Summary
public voidinit()


       
        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 voidpaint(java.awt.Graphics g)

        update(g);
public voidrun()

        //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;
            }
        }
public voidstart()

        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 voidstop()

        //Stop the animating thread.
        animatorThread = null;

        //Get rid of the objects necessary for double buffering.
        offGraphics = null;
        offImage = null;
public voidupdate(java.awt.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);