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

Preisig, Heinz A heinz.preisig at chemeng.ntnu.no
Sun Sep 5 07:32:01 BST 2010

Thanks for the help. I shall modify the code and look at the example 
too. I also decided to re-install. Shall report on results.


On 09/04/2010 03:30 PM, David Boddie wrote:
> 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
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Heinz A Preisig
Professor of Process Systems Engineering 	Private:
Øvre Bakklandet 62 B, 7013 Trondheim, Norway
Department of Chemical Engineering
Norwegian University of Science and Technology
N -- 7491 Trondheim, Norway 	Tel direct: +47 735 92807
Tel mob: +47 9754 1334
e-mail: Heinz.Preisig at chemeng.ntnu.no <mailto:Heinz.Preisig at chemeng.ntnu.no>
web: www.chemeng.ntnu.no\~preisig <http://www.chemeng.ntnu.no/%7Epreisig>

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