[SOLVED] Select a QGraphicsItem in a scene
Hi forum
I have a problem with my QGraphicsItem derived objects. They are not selectable in all situations. I guess its because of their bounding rect, which I simply return by calling ctor of QRectF and giving two points as corners. Is bounding rectangle supposed to have correct topleft and bottom-right points?
In the following image the link from B to C is selectable and there in no problem but link from A to B is not selectable.
If I move state B down, A to B is selectable and B to C can not be selected:
The bounding rectangle of both is calculated like this:
- {
- qreal lenght = line.length();
- qreal sin = (to->pos().y()-from->pos().y())/lenght;
- qreal cos = (to->pos().x()-from->pos().x())/lenght;
- fromPoint.setX(from->pos().x()+from->width()/2*cos);
- fromPoint.setY(from->pos().y()+from->width()/2*sin);
- toPoint. setX(to ->pos().x()-to ->width()/2*cos);
- toPoint. setY(to ->pos().y()-to ->width()/2*sin);
- }
1 reply
the bounding rect should always be calculated in local coordinates.
In your case, fromPoint should be (0, 0) and toPoint would equal to
- QPointF vec;
- vec = to->pos() - from->pos();
- // normalize the vector
- toPoint = vec - vecNorm * to->width();
(that is, assuming your circles and lines don’t have different scaling matrices, else you’d have to calculate their radii in line-local coordinates)
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