mathematic question

[joffo78]

Hello
I'm playing with the draw text module.
I'm trying to create a patch that allows me to adjust the gap between the letters of a comma text.
as the position is set with values from 0 to 1
it's very difficult to find the right formula to keep a proportional gap between each letter.
the idea being to adjust the poistion x of each letter by acting on a common coefficient.
I hope my request is understandable.
Thank you all.

[joffo78]

Another question about text module : is it possible to set the height and widht characters independly ?