Casting QGraphicsItem child from QGraphicsItem

[patrik08]

I solved on other Type to makeit readable ....

enum { Layer = 1 };
int type() const {return Layer;}
 
 
template <class T> inline T layer_cast(QGraphicsItem *item)
{
    return int(static_cast<T>(0)->Layer) == int(AbsoluteLayer::Layer)
        || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0;
}
 
template <class T> inline T layer_cast(const QGraphicsItem *item)
{
    return int(static_cast<T>(0)->Layer) == int(AbsoluteLayer::Layer)
        || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0;
}
 
 
 
AbsText::AbsText()
  : device(0)
{ 
 
}
/* only one connect */
LayerText *AbsText::txtControl() const
{
    if (!device) {
       AbsoluteLayer *that = layer_cast<AbsoluteLayer *>(q); 
       device = new LayerText();  /* text-api all event */
       connect(device, SIGNAL(q_cursor_newPos() ),q, SLOT(cursor_wake_up()));
       connect(device, SIGNAL(q_update(QRect) ),q, SLOT(updatearea(QRect)));
       connect(device, SIGNAL(q_visible(QRectF) ),q, SLOT(ensureVisible(QRectF)));
       ///////connect(device, SIGNAL(q_update_scene()),q, SLOT(SceneReload()));
    }
    return device;
}

enum { Layer = 1 };
int type() const {return Layer;}


template <class T> inline T layer_cast(QGraphicsItem *item)
{
    return int(static_cast<T>(0)->Layer) == int(AbsoluteLayer::Layer)
        || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0;
}

template <class T> inline T layer_cast(const QGraphicsItem *item)
{
    return int(static_cast<T>(0)->Layer) == int(AbsoluteLayer::Layer)
        || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0;
}



AbsText::AbsText()
  : device(0)
{ 

}
/* only one connect */
LayerText *AbsText::txtControl() const
{
    if (!device) {
       AbsoluteLayer *that = layer_cast<AbsoluteLayer *>(q); 
       device = new LayerText();  /* text-api all event */
       connect(device, SIGNAL(q_cursor_newPos() ),q, SLOT(cursor_wake_up()));
       connect(device, SIGNAL(q_update(QRect) ),q, SLOT(updatearea(QRect)));
       connect(device, SIGNAL(q_visible(QRectF) ),q, SLOT(ensureVisible(QRectF)));
       ///////connect(device, SIGNAL(q_update_scene()),q, SLOT(SceneReload()));
    }
    return device;
}

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[jacek]

You have to change Type to Layer in lines #8 and #14 too.