[Interest] QGraphicsView stays big

[Andre Haupt]

On Thu, Jun 07, 2012 at 05:27:27AM -0700, Waitman Gobble wrote:
> Till Oliver Knoll <till.oliver.knoll at gmail.com> wrote ..
> > 2012/6/7 Waitman Gobble <uzimac at da3m0n8t3r.com>:
> > > ...
> > > When I load an image into QGraphicsScene and add the scene to QGraphicsView,
> > the QGraphicsView expands to image size, but if I clear and load another image
> > which is smaller, it stays the same size.
> > 
> > That is by design and documented:
> > 
> >   http://qt-project.org/doc/qt-4.8/qgraphicsscene.html#sceneRect-prop
> > 
> > "...largest bounding rect of all items on the scene since the scene
> > was created (i.e., a rectangle that grows when items are added to or
> > moved in the scene, but never shrinks)."
> > 
> > Try setting it to a "null" QRectF after removing the previous and
> > loading the new image: to my understanding the next call to
> > sceneRect() should then re-calculate the bounding rectangle, which
> > should then be just as large as the new image item in the scene.
> > 
> > Cheers, Oliver
> > _______________________________________________
> > Interest mailing list
> > Interest at qt-project.org
> > http://lists.qt-project.org/mailman/listinfo/interest
> 
> Thank you.
> 
> This seems to work:
> 
> QPixmap pm(path);
> gs->clear();
> gs = new QGraphicsScene(this); //new
> gs->addPixmap(pm);
> gv->setScene(gs);
> gv->update();

That creates a memory leak every time you call that function.
What Oliver meant is to call gs->setSceneRect(QRectF()) after clearing
the scene and before adding a new pixmap to the scene. I have not tested
this though.

regards,

Andre