How to repaint entire visibleRegion - not only a part - when QScrollBar's value is changed

[qwe3]

Hi,

I have QScrollArea and big widget on it. In big widget's paintEvent I paint many things. I notice that, when I change QScrollArea's ScrollBar for example like this:

scrollArea->verticalScrollBar()->setValue(scrollArea->verticalScrollBar()->value()+1);

I don't repaint entire widget's visibleRegion, but only a part. I see that in paintEvent() method:

event->region();

I would like to change entire widget's visibleRegion always.

Of course I can do something like that:

scrollArea->verticalScrollBar()->setValue(scrollArea->verticalScrollBar()->value()+1);
repaint();

but maybe there is a better idea?

I tried in paintEvent() method something like that:

    if(event->region() != visibleRegion())
    {
        event->ignore();
        repaint(visibleRegion());
        return;
    }

But I get warning on debuq:

QWidget::repaint: Recursive repaint detected

[mpergand]

Maybe you can change the clipping with:
void QPainter::setClipRegion(const QRegion &region, Qt::ClipOperation operation = Qt::ReplaceClip)

BTW what you are trying to do is strange ...

[qwe3]

@mpergand It not works. Why is it strange? I have many if-s statements in paintEvent(), so I many times paint in different way. I have to repaint whole area, not only new part.

[mpergand]

I'm pretty sure that your if statements are wrong.
It's up to you to redraw all the elements that intersect with the redraw region.