Let’s say you cannot decide on the shape of your a, or you worked out two variations and you want to keep both. But how? There’s only one key for a on your keyboard, after all.
For cases like this, OpenType offers so-called stylistic sets. You can define up to twenty variations of your alphabet and put them into your font. Stylistic sets do not necessarily exclude each other: more than one set can be activated at the same time. One stylistic set, for instance, could consist of letters with alternative descenders, another set of alternative shapes (like the a in our exampe), a third one of alternative diagonal legs for R and K. Whatever suits your design best.
Back to our a variations. The key to the stylistic variation is the glyph name. One default a, obviously, is called
a. The alternate variation should be named
.ss01 suffix simply means it’s the a of the first stylistic set.
If you want more stylistic sets, all you need to do is add the appropriate suffix to the glyph name:
.ss02 corresponds to the second stylistic set,
.ss03 to the third one etc. Since the maximum number of sets is twenty, your suffixes can go all the way up to
If you stick to this naming convention, Glyphs can build the feature code for you. All you need to do is open your Font Info (Cmd-I), go to the Features tab and click on the circled arrow button in the bottom left corner:
You’ll see that Glyphs adds a feature called
ss01 containing a simple substitution:
a is replaced by
a.ss01. You can test it right in Glyphs by selecting the
ss01 feature from the Features popup in the bottom left of an Edit tab:
One final word of caution. Not many users know about stylistic sets. So, whatever variations you pack into them, be aware that they will be used in rare exceptions only.
If you have an
a.ss01 and you also want to use diacritics with it, there’s a simple way to do so.
Firstly, select all your diacritic a, like
abreve, and so on, and duplicate them with Cmd-D or Glyph > Duplicate Glyph. The duplicated glyphs should be selected by default, and they all have the suffix
.001. Now, press Cmd-Shift-F (or go to Edit > Find > Find and Replace) and replace
.ss01. And finally, select those
ss01 glyphs and go to Glyph > Make Component Glyph (or Opt-Shift-Cmd-C). And, there you go!