I was looking to bake some Photoshop tracking into a font. So essentially, I think, increase the width of every glyph by a proportionate value. (Another piece of software I use doesn't support tracking so I have to create a specific font variant)
But I'm not sure I understand the relationship between the values and so how to apply the maths.
So in Photoshop, I think a tracking value of, for example, 240, equates to 240/1000 em. Or 0.24.
I think I can use a global
set aw [aw+n]
to change the width but is this based on a 2048 grid? And if so, does that mean n should be 0.24x2048 = 491.52 ?
(I'm currently using 3.2.027 .. hope to update soon)
Tracking and kerning are both measured in 1/1000 em, a unit of measure that is relative to the current type size. In a 6‑point font, 1 em equals 6 points; in a 10‑point font, 1 em equals 10 points. Kerning and tracking are strictly proportional to the current type size.
So for a 1000 emu font, just add the tracking value to the AW, but for a 2048 emu font, you need to add about twice the value (ie scaled by factor of 2048/1000= 2.048)