QPainter, scale(), and setFont()

[jacek]

It might be caused by some rounding errors, since you perform all calculations on integers. Another possibility is that the "active" point of the cursor is in a bit different place than you would expect.

[c_07]

If rounding errors were indeed the case, then (and that seems to make sense), how could I best circumvent the problem? I can use floats instead of integers, but I can only use QPainter::setWindow() with a QRect, not a QRectF, and this seems to be the underlying hindrance since I set the QTransform with a call to QPainter::combinedTransform() shortly thereafter.

[jacek]

but I can only use QPainter::setWindow() with a QRect, not a QRectF

Yes, but you can avoid some of the errors by changing QRectF to QRect in the last step before the call to setWindow().

QTransform uses floats internally, so first I would check whether mapped_center has correct coordinates and whether changing it to QPointF helps.