Until i hit a wall i dont care about the calculation being 100% correct.

Using 1000 for the units per em, and asuming all screens dpi are 72, and asuming 1px is 1unit in opengl. I can now draw some fonts at what seems to be the correct size.

To finetune things i need to be certaint that the font saving routine makes the font 1000 units per em.

Need to find a way to read out screen dpi and pass it the glvg font class.
In the case of glortho and real screen size are not equal to each other i have to pass that info also to the glvg font class.