Qt-interest Archive, September 2007
Best way to clear a QGraphicsScene
Message 1 in thread
Hi all,
I have been looking for the best way to remove all QGraphicsItems from a QGraphicsScene. At the moment the simplest way seems to just reinstantiate it (myscene = new QGraphicsScene()), but somehow this does not seem like a "Good Way"(TM) to do things.
What would people here on the list recommend?
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Message 2 in thread
Hi,
Christopher Rasch-Olsen Raa schrieb:
> Hi all,
>
> I have been looking for the best way to remove all QGraphicsItems from a QGraphicsScene. At the moment the simplest way seems to just reinstantiate it (myscene = new QGraphicsScene()), but somehow this does not seem like a "Good Way"(TM) to do things.
>
You also need to delete the scene, which cleans your graphic items.
> What would people here on the list recommend?
>
>
This is what I use to clear a scene:
// graphicsScene.clear()
QList<QGraphicsItem *> list = gScene.items();
QList<QGraphicsItem *>::Iterator it = list.begin();
for ( ; it != list.end(); ++it )
{
if ( *it )
{
gScene.removeItem(*it);
delete *it;
}
}
As you can see, this basically does the same what a "delete scene" would
do, except deleting the scene itself.
I haven't done a speed test, but I do not think either version has a
noticeable performance advantage.
Jochen
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