[Qt-interest] Best Way To Force Complete Repaint of Widget

[Andre Somers]

Willy P wrote:
> I'm encountering some pretty nasty bugs embedding widgets in OpenGL
> scenes.  They are not updating properly and there are some bad
> blending issues with the scene behind it.  However, they work
> perfectly on total repaint situations, ie when you cover the widget
> with another window and then show it again.
>
> So my question is, how do I force a *total* repaint of the widget and
> all it's children every time it needs to be updated?  It's not a big
> widget so I'm not concerned w/ the performance issues.
>
> I've tried this, but it only sort of solves my problem:
>
> 	void MyWidget::paintEvent( QPaintEvent* pe )
> 	{
> 		qDebug() << "painting";
>
> 		if( pe->rect() != rect() ) {
> 			pe->accept();
> 			repaint( rect() );
> 		} else {
> 			QWidget::paintEvent( pe );
> 		}
> 	}
>
> I say sort of, b/c it works if any child widgets are embedded in
> layouts, they do not get updated.
>
> -Willy
>
> PS:  This only seems to be a problem on Mac, Windows works fine.
>
>   
In that case, why not iterate over the child widgets and force a repaint 
on them too?
Something like:

QList<QWidget *> widgets = parentWidget.findChildren<QWidget *>();
foreach (QWidget* w, widgets)
     w->repaint(rect());

If it is only nessecairy on Mac, then I would make sure it is only done 
on Mac too. Use conditional compilation for that.

André