[Qt-jambi-interest] constant item size uppon viewport scaling

[Gunnar Sletta]

On 28. mai. 2008, at 20.40, Dawid Sip wrote:

> Hi,
> as some might remember, im doing a lot with
> GraphicsView/GraphicsScene/GraphicsItem. So my recent problem is  
> that I
> have EllipseItems in my scene. These ellipses are of width and  
> hight-16.
> The viewport is scaled in the overriden resizeEvent of MyGraphicsView
> with fitInView, so that an Image can be displayed inside the
> MyGraphicsView entirely. This naturaly also makes the EllipseItems
> appear smaller than 16 pixel. I would like them to remain the same  
> size.
> So my idea is to emmit a signal in each call to resizeEvent() of
> MyGraphicsView. This signal could be catched by the EllipseItem and  
> than
> I could poly = mapToParent(this.boundingRect()) and compare the poly  
> to
> some value, and scale this EllipseItem so that the size stays the  
> same .
> Dont realy know how.
> Somehow I think this might be to complicated, is there an easier way?
>

Hi Dawid,

The flag you are looking for is:

http://doc.trolltech.com/qtjambi-4.3.4_01/doc/html/com/trolltech/qt/gui/QGraphicsItem.GraphicsItemFlag.html#ItemIgnoresTransformations

This tells QGraphicsView that the item should be rendered at the  
position according to the scene transform, but with a transformation  
according to the view.

best regards,
Gunnar


> D.
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http://doc.trolltech.com/qtjambi-4.3.4_01/doc/html/com/trolltech/qt/gui/QGraphicsItem.GraphicsItemFlag.html#ItemIgnoresTransformations