Viewing a portion of an image, scrollable

Question

Hey,
I want to write a small application that can take an image and display a small portion of that image but allow 2 dimensional scrolling so that the entire image can be viewed.
What I really want to be able to do is view a large image on my phone screen, using the up, down, left and right buttons for navigation.
Would I be right in looking at the TiledImage class in JAI?
Has anyone got any examples?
Thanks

Answer 1

You can use Tiles usign JAI. But the source image must have Tile information(eg. Tiffs).
Another way is using ImageIO package like this.
Use the following to iteratively read the required rectangle of the image.
//reader is the legal reader of the Image.
ImageReadParam readParam = reader.getDefaultReadParam();
// x is X offset, y is Y offset
Rectangle rect = new Rectangle(x,y,width,height);
readParam.setSourceRegion(rect);
BufferedImage img = reader.read(0,readParam);Now for scrolling, use addAdjustmentListner method for JScrollPane like below.
viewerScroll is JScrollPane.
AdjustmentListener listener = new MyAdjustmentListener();
viewerScroll.getVerticalScrollBar().addAdjustmentListener(listener);Sample MyAdjustmentListener is,
class MyAdjustmentListener implements AdjustmentListener {
   public void adjustmentValueChanged(AdjustmentEvent evt) {
      Adjustable source = evt.getAdjustable();
      if(evt.getValueIsAdjusting())
     return;
      int orient = source.getOrientation();
      if(orient == Adjustable.VERTICAL){
       Point p = viewerScroll.getViewport().getViewPosition();
       Rectangle rect = new Rectangle(p.x,p.y,width,height);
       //Use this rectangle again to get the BufferedImage using the first code.
}varma