increase scenerect with add item in qgraphicsview

[wagmare]

hi friends,experts,

im having a scene where items will be added continuously and out of specific sceneRect. items can be added infinite .

ex: if i set the scene rect as (0, 0, 5000, 5000) there is a chance that an item can be added say pos (5010, 5010) so i cant able to define the scene rect .
im implementing panning on graphicsview . so i need the scene rect to restrict within the items added . the item can be increased and the scene rect has to increase proposition to it. if i set 32000x32000 even if no items has been added. it wil lshow lots of empty spaces

i cant use scene->setSceneRect(scene->itemsBoundingRect()); because initially there wont be any item and i have to drop the item to scene rect.

so i need to specify initilaly some sceneRect like viewport->rect() of graphicsview. then i have to increase it when ever any items added .

so how i can increase the sceneRect when the items keep on adding and the view increases its scroll area.

thanks in advance.

[Santosh Reddy]

Any specific reason for setting the scene rect?

[wagmare]

Any specific reason for setting the scene rect?

thanks for the reply

Panning and zooming .
the items can be added one after another like a tree view .
so some branch item can be shown away from the viewport.contentsRect()

in that case i have to pan the view . like http://www.qtcentre.org/wiki/index.php?title=QGraphicsView:_Smooth_Panning_and_ Zooming

but in that example the scene rect is defined which is not in my case.

my current implementation is

when an item is added


QGraphicsView *view = this->views().at(0);
QRectF viewRect = view->contentsRect();
QRectF itemsBounds = this->itemsBoundingRect();



if(itemsBounds.width() >= sceneRect().width())
{
this->setSceneRect(itemsBoundingRect());
}else
this->setSceneRect(view->contentsRect());

if(itemsBounds.height() >= sceneRect().height())
{
this->setSceneRect(itemsBoundingRect());
}else
this->setSceneRect(view->contentsRect());


but i dont think it is a correct way .

thanks

[Santosh Reddy]

Don't set the scene rect at all, it should work by itself. Just keep adding the items.