[Qt-interest] update qgraphicsscene

[caius ligarius]

Is there a way to automatically center the image. I think setSceneRect takes
top-left corner position and width of qgraphicsview?

I tried 0,0 (below) but this puts the topleft corner of the image at (0,0)
in the viewport.

(I guess I could calculate this position for every image....)

void populateScene(QImage* image)
{
   QGraphicsScene* scene = new QGraphicsScene;
   QPixmap np = QPixmap::fromImage(*image);

   qGraphicsItem->setPixmap(np);
   scene->addItem(qGraphicsItem);
   scene->setSceneRect(0,0,qgraphicsView->width(),qgraphicsView->height());

   qgraphicsView->setPixmap(np);

}


On Mon, May 24, 2010 at 12:35 PM, Esben Mose Hansen <kde at mosehansen.dk>wrote:

> On Monday 24 May 2010 19:43:20 caius ligarius wrote:
>
> > I tried creating a QGrpahicsScene member variable which belongs to the
> same
> > class as the above function but the problem I ran into was that everytime
> I
> > updated the scene with the new image (scene->additem(qGraphicsItem)) the
> > image got shifted and was not centered around the viewport.
> >
> > My questions is what is the most optimal way (in terms of speed and
> memory
> > management) to update QGraphicsView widget with a new QImage?
>
> Set the new image on "qGraphicsItem", and update the "scene" with
> setSceneRect() to match the bounds to avoid the off-center effect.
>
>
> --
> Kind regards, Esben
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