How to do font arithmetic with QFont in (non ingegral) pixels.

[Audetto]

I am trying to get a true monospace font on Pi 400, which uses Qt 5.11.3.

QFont f = QFontDatabase::systemFont(QFontDatabase::FixedFont);
if(f.styleHint() != QFont::TypeWriter)
{
    f.setFamily("Monospace"); // Force Monospaced font
    f.setStyleHint(QFont::TypeWriter);
}

The problem I have is that the conversion pixel <-> point requires rounding.
In an editor, if one tries to compute where is the n-th character or which character is under the n-th pixel, an integer conversion would be much easier.

Is there such a thing as a Monospace font with integral (in pixel) size?
Or can I convert one?

[Audetto]

Answering my own question.
Bite the bullet and use QFontMetricsF and do some rounding where necessary.