Performance trouble on repaint

Question

Hello there!
I've got a GUI question for you.
Is there a way to display (repaint) just what is seen in the clipping area of a Graphics?
That is to say, if I have a Shape that "crosses" the clipping area (the shape is bigger than the visible area, and just a part of it will be displayed), is there a way to draw just the visible part of the Shape?
Because in my soft, the user can draw shapes on a picture, and can also perform a zoom. The problem is that when we have a high zoom factor, it seems that the Grapsics takes a long time to draw the Shapes.
Moreover, for some particular reasons, we have to "repaint" really frequently the frame, so this problem is really troublesome.
Here is the code used to draw the Shapes (used for each Shape drawn on the picture):
     public void draw(Graphics2D g2d, AffineTransform aff,
               Color shapeBackground, Color shapeOutline, float shapeTransparency,
               float shapeThickness, float[] shapeStyle, String texturePath,
               Color splitBackground, Color splitOutline, float splitTransparency) {
          g2d.setStroke(new BasicStroke(shapeThickness, BasicStroke.CAP_ROUND, BasicStroke.JOIN_MITER, 10.0f, shapeStyle, 1));
          g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, shapeTransparency));
          Shape rat = aff.createTransformedShape(shape);
          g2d.setColor(shapeBackground);
          // gestion de la texture
          if (texturePath != null && texturePath.length() > 0) {
               BufferedImage img;
               img = ImageFilesReader.read(texturePath);
               if (img != null) {
                    g2d.setPaint(new TexturePaint(img, rat.getBounds2D()));
          g2d.fill(rat);
          g2d.setColor(shapeOutline);
          if (shapeStyle == CustomizeROIAppearanceDialog.EMPTY_STROKE) {
               g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0f));
          else {
               g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1.0f));
          g2d.draw(rat);
          g2d.setStroke(new BasicStroke());
          if (isSelected){
               split.draw(g2d,aff,splitBackground,splitOutline,splitTransparency);
If it is not possible, do you think that performing a double-buffering strategy could improve the speed of the repaint?...
Thanks a lot!

Answer 1

In fact, I don't ask the Graphics to repaint outside of my component. I have a picture displayed in a JScrollPane, so some parts of my picture and some of my Shapes can lay outside of the visible zone... And so, I would like to draw just the parts of the Shapes that are visible (not the whole Shapes that have visible part, but just ht visible part, if it's possible)
You said :
"Perhaps you could also try manually clipping the shape before you pass it to the affine transform. Or only pass the visible bounds when you set the texture paint. But those are just guesses. "
How can I do that?
Thanks!