How QML determines default font.pixelSize

[SeeLook]

Hi.

I'm trying to figure out how QML determines font.pixelSize, because it is not simply FontMetrics.height (or qApp->fontMetrics().height())
I. e. for system font size set to 12:
qApp->font().pointSize() is exactly 12 the same as QML font.pointSize
qApp->fontMetrics().height() is 19 (the same as QML FontMetrics)
but
qApp->font().pixelSize() is -1 mens undefined
whereas QML font.pixelSize is 16
So how to obtain this last value, knowing system font size (pointSize) before QML will be initialized?

[SeeLook]

OK. I've got it....

auto pixelSize = qApp.font().pointSizeF() / 72.0 * qApp->primaryScreen()->logicalDotsPerInch();