[Qt-interest] Move lot of QGraphicsItem or scrol the QGraphicsView ?

[Pritam Ghanghas]

Hi

What was your viewportUpdateMode when you were moving graphicsItems.
AFAIK, move items should be faster but only with
BoundingRectViewportUpdate/MinimalViewportUpdate/SmartViewportUpdate
mode. For FullViewportUpdate they should be same.


-- 
Thanks,
Pritam


On Wed, 2010-07-07 at 22:14 +0530, mario wrote:
> Hi all,
> 
> I'm on an embedded device with wince6.
> I have a lot of QGraphicsItem (some sort of rounded rectangle with 2
> text QGraphicsTextItem inside) to move at the same time.
> 
> The view is sized to show only a subset of them ( 20 of 100 ) and they
> are all aligned horizontally.
> 
> At the first time I tried to resize the scene to cover all of them and
> I used the QgraphicsView's scrollbars, but it was too slow.
> 
> So I resized the scene to the same size of the view, I grouped all the
> items in a QGraphicsItemGroup and set the movable flag on it. So I
> could move it with the mouse.
> Even this was too slow.
> 
> Which of them is the right way?
> I can try to improve the code, but I need to know which is the best
> method (in performance speaking).
> Any hints?
> tnx
> 


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