• [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.
!http://s3.picofile.com/file/7372578167/snapshot23.jpeg(1)!
If I move state B down, A to B is selectable and B to C can not be selected:
!http://s3.picofile.com/file/7372578709/snapshot24.jpeg(2)!

The bounding rectangle of both is calculated like this:
@
QRectF Move::boundingRect() const
{
QLineF line(from->pos(),to->pos());
qreal lenght = line.length();
qreal sin = (to->pos().y()-from->pos().y())/lenght;
qreal cos = (to->pos().x()-from->pos().x())/lenght;
QPointF fromPoint, toPoint;
fromPoint.setX(from->pos().x()+from->width()/2cos);
fromPoint.setY(from->pos().y()+from->width()/2
sin);
toPoint. setX(to ->pos().x()-to ->width()/2cos);
toPoint. setY(to ->pos().y()-to ->width()/2
sin);
return QRectF(fromPoint,toPoint);
}
@

• Posts 2 | Views 1491
• [SOLVED] Select a QGraphicsItem in a scene

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
QPointF vecNorm /= (vec.x() * vec.x() + vec.y() * vec.y());

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)

Posts 2 | Views 1491
Internal error.

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