Painting with QPrintPreviewWidget - different results on Windows, Linux and Mac

[nando76]

Hi,
i want to paint a rectangle of 100mm x 100mm on a QPainter (or printer or what else)
and display it in a QPrintPreviewWidget.

Somehow the results on the screen differ on Windows, Linux and my MacOS X (Mavericks) machine.

Same code has different output (same on Mac + Linux) but different on Windows.
I paint a rectangle at position 0,0... and on Windows there is a white border (margin?) but same code
on linux and mac works as expected ( rectangle at 0,0 starts direct in top left corner without any margins).

Printing and PDF export works great only the output of the pages of QPrintPreviewWidget differ.

See a screenshot attached dispalying the output on Windows and Mac...
"See image with different results on windows and mac":https://www.dropbox.com/s/vorgq1czurksusd/Mac-Windows-Qt5.2-QPrintPreviewWidget-Bug.png

Then painting like this:

@
void TestSite::paintEvent(QPaintEvent *)
{
QPainter painter(this);

painter.fillRect(0, 0, 500,500, QBrush(Qt::red));

}
@

The result differs on each machine. Only some pixels but it's not equal as expected.

Any ideas whats going on here?

Greetings
Nando