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[Bug awt/26594] New: AWT repaint fails to call update() for Lightweights


From: hendrich at informatik dot uni-hamburg dot de
Subject: [Bug awt/26594] New: AWT repaint fails to call update() for Lightweights
Date: 7 Mar 2006 13:47:44 -0000

See the attached testcase for a simple animation on an AWT component.
Please edit the file to uncomment either the 

LCDCanvas extends Canvas   or
LCDCanvas extends Panel

lines. LCDCanvas is an inner class, but this shouldn't matter.

When running with the reference implementation, repainting calls the
update( Graphics ) method, which in turn dispatches to paintMatrix(),
and the animation runs flicker-free. The paint() method is only called
after external events, e.g. resizing the window.

Running with jamvm+classpath (cvs 2006.02.28) shows that repainting 
directly calls paint( Graphics ). This is wrong, and results in enormous
flickering. This will break applications whose painting algorithms make
use of the update() method.

Note that jamvm+classpath works correctly for heavyweight components, 
as can be seen by uncommenting the "LCDCanvas extends Canvas" line and
recompiling.


-- 
           Summary: AWT repaint fails to call update() for Lightweights
           Product: classpath
           Version: 0.90
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: awt
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hendrich at informatik dot uni-hamburg dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26594





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