Display a large sequence of images like a video.

Question

I want to display a large sequence of images (.jpg) like a video, something like a Component that displays an image and a TimerTask that changes that image every 50 milseconds and repaints:
class SlideShow extends Component
     private Timer timer;
     private TimerTask imageFliper;
     private Image currentImage;
     private Image nextImage;
     private int arraysize;
     private int arrayoffset;
     private int currentposi;
     String fileMask;
     public SlideShow(int offset, int size, String filemask)
          super.setSize(640,480);
          currentposi = arrayoffset = offset;
          arraysize = size;
          fileMask = filemask;
          timer= new Timer();
          nextImage = Toolkit.getDefaultToolkit().getImage(fileMask.replaceFirst("#",leftZero(currentposi,4)));
          imageFliper = new TimerTask()
               public void run()
                    currentImage = nextImage;
                    repaint();
                    if(++currentposi > arrayoffset + arraysize)
                         currentposi = arrayoffset;
                    nextImage = Toolkit.getDefaultToolkit().getImage(fileMask.replaceFirst("#",leftZero(currentposi,4)));
          timer.schedule(imageFliper, 0, 50);
     public void paint(Graphics g)
          g.drawImage(currentImage,0,0,super.getWidth(),super.getHeight(),this);
     public void update(Graphics g)
          paint(g);
     static public String leftZero(int target,int leftcount)
          StringBuffer sb = new StringBuffer();
          int i = (int)Math.pow(10,leftcount-1);
          while(i!=1)
               if(target<i)
                    sb.append("0");
                    i=i/10;
               else
                    break;
          sb.append(Integer.toString(target));
          return sb.toString();
     public static void main(String[] args) 
          Frame f = new Frame("slide show");
          SlideShow s = new SlideShow(1,1000,"intro\\intro#.jpg");
          f.add(s);
          f.addWindowListener(new WindowAdapter()
                         public void windowClosing(WindowEvent e){System.exit(0);}
          f.pack();
          f.setSize(640,480);
          f.setVisible(true);
}but just using the Image class seems to be unefective.
Does anyone kwon a library that does this fast and efective?
or should i just convert the images to a media file and use a media library?
Message was edited by:
nmfmr

Answer 1

Firstly if you're loading images with Toolkit you'll nbeed to use MediaTracker (see the Javadoc for full and clear instructions).
Secondly, be aware of how long it takes to load image data, allocate the memory for it, and decode it. This is where you're going to suffer and it's the fundamental flaw in the plan of simulating video by flipping single frames: it's highly unlikely you'll manage it quickly enough. As above, 50ms is quite optimistic.
You could do your loading up-front and buffer a load of images - there are a few strategies you could use for this. But bear in mind that (a) this is going to be very memory hungry, and (b) if your image load time is greater than your frame display time you're always going to be fighting a losing battle. But it should work for very small animations.
Run yourself some tests: write yourself a simple test class which just loads an image in its main() method using a MediaTracker. It'll tell you how long loading the image takes. Of course, if you're doing it in an applet then you've got all sorts of other factors to consider and the load times will be high.