Qt-interest Archive, March 2007
Delay Redraw of QGraphicsScene?
Message 1 in thread
Can I enqueue updates to a QGraphicsScene before it is redrawn?
Specifically, I would like to delay redrawing the scene while I
reposition, show, and hide thousands of items. Currently, after each
change to the scene, Qt redraws the entire scene. I would like to delay
this until all the graphicsitem's settings are set, then redraw the
scene only once. Is there a way to do this? Any help would be greatly
appreciated.
-Chris Portka
--
[ signature omitted ]
Message 2 in thread
Chris Portka wrote:
> Can I enqueue updates to a QGraphicsScene before it is redrawn?
> Specifically, I would like to delay redrawing the scene while I
> reposition, show, and hide thousands of items. Currently, after each
> change to the scene, Qt redraws the entire scene. I would like to
> delay this until all the graphicsitem's settings are set, then redraw
> the scene only once. Is there a way to do this? Any help would be
> greatly appreciated.
Qt should optimize paintEvents for you, but if you want you can do the
following:
scene->blockSignals(true);
//Do long opertaions
scene->blockSignals(false);
scene->update(); //Force one huge update
--Justin
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fn:Justin Noel
n:Noel;Justin
org:ICS;Engineering
adr:;;54B Middlesex Trpk;Bedford;MA;01730;USA
email;internet:justin@xxxxxxx
title:Sr. Consulting Engineer / Certified Qt Instructor
tel;work:(617) 621-0060
url:http://www.ics.com
version:2.1
end:vcard
