[Qt-interest] XServer slower than windows ?

[Glenn Pierce]

Hi

I have code that is at the bottom of this email that paints an image on a
abstract scroll area.
This image which can be very large scrolls very fast under windows.

However, under Linux, scrolling is so slow it is unusable.
I have tried under an Intel card (GM965/GL960 Integrated Graphics)
and an old NVidia card with the proprietary driver.

Does someone have a hint why this is slow on Linux ?
Is it the client server design of the XServer ?


QScrollBar *hs = this->horizontalScrollBar();
QScrollBar *vs = this->verticalScrollBar();

int horz*pos = hs->value();
int vert*pos = vs->value();

QPainter painter(this->viewport());

painter.scale(2, 2);
painter.translate(-horz*pos, -vert*pos);

QRect exposedRect =
painter.matrix().inverted().mapRect(event->rect()).adjusted(-1, -1, 1,
1);

// the adjust is to account for half pixels along edges
painter.drawPixmap(exposedRect, this->pix, exposedRect);



Regards

Glenn
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