User Guide

but don’t want to have to do it all manually—the computer
must be good for something, right?
What we call “assisted metrics,” other people might refer to
as “equivalence classes.” An equivalence class is a rule
which dictates what other characters’ attributes should be.
These rules can involve sidebearings, widths, and kerning
pairs. Equivalence classes are like programming languages
for fonts. That’s why not everybody likes them!
The best way to explain all this is by example, so let’s dive
right in.
Metrics Assistance
Metrics Assistance can be found under the Metrics
Window. Here is how the Metrics Assistance dialog box
looks, with one equivalence class:
Each line of this dialog box can have its own equivalence
class. When you have entered more than ten classes, a
scroll bar will appear along the right side of the box, which
will allow you to create more classes. You can have lots of
equivalence classes; they are limited only by available
memory.
Insert Line and Delete Line allow for intuitive grouping
when relating characters to one another.
In the left-hand column, you choose the base character. This
is the character whose attributes will determine the values
applied to the other members of that particular class.
Next, you choose what attributes the equivalence class is
going to govern.
Then, you choose the other members in the class: these are
the letters whose values are going to be set according to
Fontographer User's Manual
5: Metrics: Spacing and Kerning Page #22