Scrolling QGraphicsView and QGraphicsScene

Question

I have QGraphicsScene instance set to QGraphicsView on the GUI with scrollbars enabled and full view port update. But when I scroll my graphics view I get the items added to qgraphics scene disappeared on some point, though they are added in code correctly and are expected to be displayed upon scroll ( custom class inherited from QGraphicsItem ):

  class CSquare : public QObject, public QGraphicsItem

paint method is implemented as follows:

void CSquare::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    static int sz;
    painter->setFont(fnt_);
    painter->fillRect(this->r,this->br);
    painter->drawRect(this->r);
    //painter->drawText(this->p,this->txt);
    if (txt == "")
        return;
    if (fnt_.pixelSize()>0)
        sz = fnt_.pixelSize();
    else
        if (fnt_.pointSize()>0)
            sz = fnt_.pointSize();
        else
            if (fnt_.pointSizeF()>0)
                sz = fnt_.pointSizeF();

    switch (this->al_flag)
    {
    case 1:
        painter->drawText(this->p.x(),this->p.y(),sz*txt.size(),2*sz,Qt::AlignRight,this->txt);
        break;
    case 2:
        //painter->drawText(this->r,Qt::AlignLeft,this->txt);
        painter->drawText(this->p.x(),this->p.y(),sz*txt.size(),2*sz,Qt::AlignLeft,this->txt);
        break;
    case 3:
        //painter->drawText(this->r,Qt::AlignCenter,this->txt);
        painter->drawText(this->p.x(),this->p.y(),sz*txt.size(),2*sz,Qt::AlignCenter,this->txt);
        break;
    case 4:
        //painter->drawText(this->r,Qt::AlignJustify,this->txt);
        painter->drawText(this->p.x(),this->p.y(),sz*txt.size(),2*sz,Qt::AlignJustify,this->txt);
        break;
    }
}

One can see how they disappear on application run on this video screen cast:

https://www.box.com/s/h4h94×1avgay1crzvyzx

Can somebody hint what is the problem, how to resolve so the graphics items will not disappear on the view?

Thanks in advance.

That box.com link is broken

Chris
– Chris

2013-02-19 00:55:50 +00:00
Commented Feb 19, 2013 at 0:55 — Chris
– Chris, Commented Feb 19, 2013 at 0:55

user3466514 · Accepted Answer · 2016-05-19 21:02:24Z

1

Yep, sorry. The problem is already solved: the problem was in custom function in the inherited class:

QRectF boundingRect() const;

That should return valid rectangle. Now I fixed that in my project and m going to remove the video.

Thank you for your attention.

edited May 19, 2016 at 21:02

user3466514

33 bronze badges

answered Feb 19, 2013 at 14:27

St Sht

193 silver badges11 bronze badges

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