How to make JScrollPane scroll faster?

Question

Hi,
I have tried to develop on a program to zoom in or zoom out the image�a graph which is plotted using the method draw from Graphics2D. In the program, I am given about 1000 points, which are supposed to be plotted one by one suing the draw method, which later form a graph.
I have put the JPanel, where the output of the graph is displayed, into a JscrollPane to enable scrolling of large image. However, when I am trying to scroll the image, it happen to me that the scrolling is extremely slow. When I click at the scrolling bar to scroll down the image, it take some time before the image is scrolled down.
My doubt will be is there any method to make the scrolling on the JscrollPane to become faster?does this involve double buffering?
Thank you.

Answer 1

This may not be the answer to your problem, but I thought I would throw it out there. One reason it might scroll slowly is because by default the JScrollPane only moves 1 pixel for every click of the scroll bar. You can adjust this by having your JPanel implement the Scrollable interface.
Here is a code sample -
// implement Scrollable interface
public Dimension getPreferredScrollableViewportSize()
return getPreferredSize();
public int getScrollableBlockIncrement( Rectangle r, int orientation, int direction )
return 10;
public boolean getScrollableTracksViewportHeight()
return false;
public boolean getScrollableTracksViewportWidth()
return false;
public int getScrollableUnitIncrement( Rectangle r, int orientation, int direction )
return 10;
Whatever number you have your getScrollableUnitIncrement and getScrollableBlockIncrement methods return is how many pixels your component will scroll for each click of the scroll bar.
Give this a try.