[Qt-interest] Have any recommendations of enhance the GUI speed of using GraphiscView/Scene/Items ?

[Ross Bencina]

On 29/10/2011 1:21 AM, David García Garzón wrote:
> We have a similar application and we are experiencing similar scalability
> problems. So any solution would be of our interest too.
 >
> At the time we implemented it, GV tecnology was in its inception, the wires as
> items invalidated the whole square and forced too many redraws. We ended up by
> drawing the wires as background but now I would have guess that GPathItem
> invalidation would be more optimal than that. Isn't it?

Hi David :-)

I don't use QPathItem, but what I do is cache my QPainterPath objects so 
that they only get recreated when they absolutely need to. Usually the 
item paint() events just draw the pre-existing QPainterPath.

This works OK for me but I do have other rendering performance problems 
with QGraphicsView (updating lots of small items scattered accross the 
scene seems very expensive). So any hints for improving QGraphicsView 
performance would be welcome here too.

Thanks!

Ross.