title: QGraphicsItem::ItemPositionHasChanged issues
body: <p>I have a QGraphicsItem and I just want to detect when the position of the object is changed.</p>
  
  <p>I have this function:</p>
  
  <pre><code>QVariant ObjectGraphicsItem::itemChange(GraphicsItemChange change, const 
                                          QVariant &amp;value) {
     if (change == QGraphicsItem::ItemSelectedHasChanged) {
        //do something
     }
     if (change == QGraphicsItem::ItemPositionHasChanged ) { 
        //here is the issue   
     }
        return QGraphicsItem::itemChange(change, value);
  }
  </code></pre>
  
  <p>My problem is that the following condition </p>
  
  <pre><code>change == QGraphicsItem::ItemPositionHasChanged 
  </code></pre>
  
  <p>is meet also when I change the size of the object.
  What I need is something like below:</p>
  
  <pre><code>if (change == QGraphicsItem::ItemPositionHasChanged ) { 
     objectPositionChanged();
  }
  if (change == QGraphicsItem::ItemSizeHasChanged ) { 
     objectSizeChanged();
  }
  </code></pre>
  
  <p>but QT does not have <strong>QGraphicsItem::ItemSizeHasChanged</strong></p>
  
  <p>Thank you in advance for your help.</p>