Re: updating an ImageIcon's backing BufferedImage content from multiple threads

Knute Johnson <>
Mon, 06 Apr 2009 17:44:11 -0700
John B. Matthews wrote:

In this example, a javax.swing.Timer, which uses invokeLater(), notifies
an Observer on the EDT. The happens-before relationship ensures
visibility, but not necessarily effective synchronization. The effect is
easy to see when the Fill checkbox is set:


I don't think I'm seeing the lack of synchronization. It appears to
work just like I would expect. At high rates of fill there appears to
be some tearing but that is a video byproduct I think.

Speaking of things such as high speed drawing. My preferred method at
the moment for high speed drawing is to draw to a BufferedImage and then
use invokeAndWait() to call paintImmediately(). On a multiprocessor
machine I can also use a loop timer with System.nanoTime() to control
the rate. This produces the smoothest and fastest video updates (full
screen exclusive mode exempted) that I've been able to do.


Knute Johnson
email s/nospam/knute2009/

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