Re: A flickering case

[Uwe R. <Uwe...@ti...>]

Hi Kamran,

Don't want to comment your efforts in detail, but all what you are doing is to 
slow down painting by useless pixmap copies.

1 second should be long enough to paint a lot of stuff, so you should spend 
some time on finding out what the reason for your flickering is. 
Flickering means that you have too many visual changes. Try to set breakpoints 
between the changes, or add sleeps in your code, to identify what changes 
between them.

One thing you could try is to paint the background of the canvas yourself. It 
has the effect, that in case of some repaints the canvas is not erased with 
its background, while the application is busy with painting to the canvas 
cache.

1) 
plot->canvas()->setBackgroundMode(Qt::NoBackground);
2) 
void YourPlot::drawCanvas(QPainter *painter)
{
        const QColorGroup::ColorRole role =
                QPalette::backgroundRoleFromMode(backgroundMode());

        painter->setPen(Qt::NoPen);
        painter->setBrush(colorGroup().color(role));
        painter->drawRect(contentsRect());

	QwtPlot::drawCanvas(painter);
}

Uwe