[PyQt] upgrade to ubuntu 10.04 -- problem with graphics

David Boddie david at boddie.org.uk
Sat Sep 4 14:30:42 BST 2010


On Sat Sep 4 08:00:06 BST 2010, Preisig, Heinz A wrote:

> After upgrading Ubuntu 9.10 to 10.04 I encounter some problems with
> running a graphics application I built last year. It uses the mechanisms
> described in the example "elasticnodes". The two application represent a
> graph, which when moving the nodes also update the location of the arcs.
>
> In both cases the arcs are not updated. In fact the example does not
> show the arcs when starting it. My application does show the arcs, but
> it does not update. I dug for some hours in the code, but could not find
> a problem. It seems it does not get into the "itemChange" method of the
> "QGraphicsItem" class. Some manipulations resulted in abortion of the
> task, which when running from within Eclipse did not produce an error
> message. From the terminal I got an occasional segmentation fault.

I don't know why you are getting segmentation faults, but the problem with
the itemChange method is due to a change in behaviour in Qt 4.6. You now
need to call the item's setFlag method with the ItemSendsGeometryChanges
flag to get notifications when items move.

David


More information about the PyQt mailing list