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List:       batik-dev
Subject:    Re: One pixel high rendering anomaly
From:       thomas.deweese () kodak ! com
Date:       2006-12-31 13:36:36
Message-ID: OF57DC5417.A31D40A4-ON85257255.0049ECB7-85257255.004AC11F () knotes ! kodak ! com
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Hi Dieter, Cameron,

"Dieter von Holten" <info@dvholten.de> wrote on 12/30/2006 03:11:54 AM:

> i saw stuff like that when i did animation with graphics2D a while ago.
> the smear-effect comes from updating the position of the moving object
> indepently of the drawing.

   This definitely looks like a bug in the dirty region management
(see batik.gvt.UpdateTracker).  However, the GVT tree should track 
this stuff automatically. 

   In the past bugs along these lines have shown up when an element 
changes it's bounds and then a higher level group's transform 
changes or the like (this is a tricky case because if the higher 
group just dirties it's current bounds it won't include the old 
bounds of the shape).

> i suspect a problem deep in the repaint-stuff: on my todo-list i have 
some
> strange rendering effects from script-generated animations. the thing to
> investigate is not a smear-effect, but it seems, that the last update is 
not
> painted (the script stops when done and somehow prevents the last 
repaint or
> update).

   Hmm, sounds like something very odd.  Is it possible the script isn't
returning for some reason?  Also are you viewing this in the canvas or
some other way?

> The way i try to debug this is 'unusual': this worked long ago. So i get
> older versions from svn to find that delta, which introduced the 
problem..

   This is actually a common debugging technique and just one example of 
why good revision control is so important.

> Seems, regard was/is not used too often.

   Is there a regression in this area?  I just went through
and looked at everything and there were a few 'odd' results
I don't recall anything in this area...


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<br><font size=2 face="sans-serif">Hi Dieter, Cameron,</font>
<br>
<br><font size=2><tt>&quot;Dieter von Holten&quot; &lt;info@dvholten.de&gt;
wrote on 12/30/2006 03:11:54 AM:<br>
<br>
&gt; i saw stuff like that when i did animation with graphics2D a while
ago.<br>
&gt; the smear-effect comes from updating the position of the moving object<br>
&gt; indepently of the drawing.</tt></font>
<br>
<br><font size=2><tt>&nbsp; &nbsp;This definitely looks like a bug in the
dirty region management</tt></font>
<br><font size=2><tt>(see batik.gvt.UpdateTracker). &nbsp;However, the
GVT tree should track </tt></font>
<br><font size=2><tt>this stuff automatically. &nbsp;</tt></font>
<br>
<br><font size=2><tt>&nbsp; &nbsp;In the past bugs along these lines have
shown up when an element </tt></font>
<br><font size=2><tt>changes it's bounds and then a higher level group's
transform </tt></font>
<br><font size=2><tt>changes or the like (this is a tricky case because
if the higher </tt></font>
<br><font size=2><tt>group just dirties it's current bounds it won't include
the old </tt></font>
<br><font size=2><tt>bounds of the shape).</tt></font>
<br>
<br><font size=2><tt>&gt; i suspect a problem deep in the repaint-stuff:
on my todo-list i have some<br>
&gt; strange rendering effects from script-generated animations. the thing
to<br>
&gt; investigate is not a smear-effect, but it seems, that the last update
is not<br>
&gt; painted (the script stops when done and somehow prevents the last
repaint or<br>
&gt; update).<br>
</tt></font>
<br><font size=2><tt>&nbsp; &nbsp;Hmm, sounds like something very odd.
&nbsp;Is it possible the script isn't</tt></font>
<br><font size=2><tt>returning for some reason? &nbsp;Also are you viewing
this in the canvas or</tt></font>
<br><font size=2><tt>some other way?</tt></font>
<br>
<br><font size=2><tt>&gt; The way i try to debug this is 'unusual': this
worked long ago. So i get<br>
&gt; older versions from svn to find that delta, which introduced the problem..<br>
</tt></font>
<br><font size=2><tt>&nbsp; &nbsp;This is actually a common debugging technique
and just one example of </tt></font>
<br><font size=2><tt>why good revision control is so important.</tt></font>
<br>
<br><font size=2><tt>&gt; Seems, regard was/is not used too often.<br>
</tt></font>
<br><font size=2><tt>&nbsp; &nbsp;Is there a regression in this area? &nbsp;I
just went through</tt></font>
<br><font size=2><tt>and looked at everything and there were a few 'odd'
results</tt></font>
<br><font size=2><tt>I don't recall anything in this area...</tt></font>
<br>
<br>
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