QGraphicsItem movement

[azi021]

Hi,

how can i remove the jerky movement effect when moving a QGraphicsItem?

the paltform is ubuntu 9.10 and this is the item code:
@ #include "asportowindow.h"

AsportoWindow::AsportoWindow(MainScene *p,int w,int h,MysqlConnector2
*c,Logger2 *l)
{
  logger=l;
  conn=c;
 
  width=w;
  height=h;
 
  parent=p;
  this->setParentItem(parent);
  setCacheMode(QGraphicsItem::DeviceCoordinateCache);
 
  movable=false;
}
 
void AsportoWindow::paint(QPainter *painter, const
QStyleOptionGraphicsItem *option, QWidget *)
{
  painter->setPen(QPen(Qt::black, 0));
  painter->setBrush(QColor(78,73,73));
  painter->drawRect(0,0,width,height);
}
 
QRectF AsportoWindow::boundingRect() const
{
    return QRectF(0,0,width,height);
}
 
QPainterPath AsportoWindow::shape() const
{
   QPainterPath path;
   path.addRect(0,0,width,height);
   return path;
}
 
 
void AsportoWindow::mousePressEvent( QGraphicsSceneMouseEvent * event )
{
    startMovement=event->scenePos().x();
 
    startX=this->scenePos().x();
    startY=this->scenePos().y();
 
    movable=true;
    lastCurrentX=startX;
 }
 
void AsportoWindow::mouseReleaseEvent( QGraphicsSceneMouseEvent * event )
{
   endMovement=event->scenePos().x();
 
   if(abs(currentMovement)<200)
   {
      setPos(0,startY);
   }
   else
   {
       setPos(startX,startY);
   }
 
   movable=false;
}
 
void AsportoWindow::mouseMoveEvent( QGraphicsSceneMouseEvent * event )
{
    currentMovement=event->scenePos().x();
 
    if(currentMovement<startMovement)
    {
     //movememnt is right to left
     int delta=startMovement-currentMovement;
 
     lastCurrentX=currentX;
     currentX=startX-delta;
 
     width=width+delta;
 
     setPos(currentX,startY);
    }
}

@

Thanks!