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

[David Boddie]

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