help on tables

typotheticals
16.May.2007 5.31am
typotheticals's picture

What is a g sub table ? and how do you make one ?
Been told it has g pos tables but no g sub tables. I’m lost.



Village
16.May.2007 5.55am
Village's picture

A GSUB table is a substitution lookup. The most common one is for ligatures:

feature liga {
sub f i by fi;
sub f l by fl;
} liga;

And that’s the most basic version of it.

OT fonts only seem to work properly if they have at least one GSUB and one GPOS. (Kern is the “big” GPOS. GSUB is how small caps, alternate numeral sets, etc. are achived.)