[Qt-interest] QGraphicsItem jerky movement

[Riccardo Roasio]

Hi,


you are right..

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);
     }
}


2010/7/16 Andre Somers <andre at familiesomers.nl>:
> Op 16-7-2010 10:33, Riccardo Roasio schreef:
>> Hi,
>>
>> how can i remove the jerky movement effect when moving a QGraphicsItem?
>>
>> Thanks,
>> Riccardo
>> _______________________________________________
>>
> Did you forget to chant the magic incantations for smooth movements? Qt
> responds very well to charms and other forms of magic, I am told...
>
> Or, perhaps more helpful: we mere mortal programmers don't have crystal
> balls that show us your code. You should provide enough information for
> us to help you, such as what it is you are trying to do, on what
> platform, using what (relevant) code, and preferably a link to a small,
> self-contained example that demonstrates the issue.
>
> André
>
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