How to scale text drawn by the Painter

[dolezvo1]

I am aware that you can change the size of the text drawn by Painter::text by adjusting the font size of the FontId. There are issues with that, though, and that makes me wonder if I'm not missing some other way to do that. Specifically from my observation drawing text using 32 point font is not the same as the double of drawing 16 point font, but I'm under impression I would like to be able to draw the text bigger with a fixed font size, as to scale exactly.