[Interest] QGraphicsView & QGraphicsScene

[Igor Mironchik]

On 14.06.2016 15:28, Igor Mironchik wrote:
> Hi,
>
> On 14.06.2016 15:14, Igor Mironchik wrote:
>> Hello.
>>
>> I'm working on project that use QGraphicsView.
>>
>> I interactively group child elements (items) and ungroup. Everything 
>> is fine, but when I do ungroup, sceneRect in view increases. Look:
>>
>> scene QRectF(0,0 800x630) form pos QPointF(0,0)
>>
>> sceneRect QRectF(-5,-5 805x640)
>>
>> sceneRect QRectF(-5,-5 805x640) <-- Normal state
>>
>> sceneRect QRectF(-5,-186 805x821) <-- Here I did ungroup and 
>> sceneRect increased.
>>
>> sceneRect QRectF(-5,-186 805x821)
>>
>> sceneRect QRectF(-5,-186 805x821)
>>
>> sceneRect QRectF(-5,-186 805x821)
>>
>> scene QRectF(0,0 800x630) form pos QPointF(0,0) <-- But scene's 
>> itemsBoundingRect() is unchanged.
>>
>> What it can be? Thank you.
>>
>
> I found in the docs:
>
> sceneRect: QRectF <../qtcore/qrectf.html>
>
> This property holds the scene rectangle; the bounding rectangle of the 
> scene.
>
> The scene rectangle defines the extent of the scene. It is primarily 
> used by QGraphicsView <qgraphicsview.html> to determine the view's 
> default scrollable area, and by QGraphicsScene <qgraphicsscene.html> 
> to manage item indexing.
>
> If unset, or if set to a null QRectF <../qtcore/qrectf.html>, 
> sceneRect() will return the 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).
>
> And this "never shrinks" is the root of the problem. So my question is 
> how to shrink sceneRect() to the normal size? Thank you.
>

Possible solution is:

scene()->setSceneRect( scene()->itemsBoundingRect() );
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20160614/dfc2b0d3/attachment.html>