I’d like to use the character ‘ō’ in an app we’re building, and in its accompanying promotional website. We’re using Gill Sans for the interface font, but it seems to lack this character in the regular weight (it’s there in light). Am I missing something?
I just checked the font, and it's correct, that character is not there in Gill Sans, Gill Sans Bold, Gill Sans Italic, or Gill Sans Light Italic. In fact, I've been checking out Monotype who made the font files, and they don't have that character in most of their versions of the typeface either. Monotype does offer a Gill Sans Cyrillic Volume which you could license, if Gill Sans and the o with a macron are both essential to your app.
From Monotype's site, here's a sample of Gill Sans Cyrillic Regular:
The closest one I could find is
LATIN SMALL LETTER O WITH MACRON Unicode: U+014D, UTF-8: C5 8D
Now you could try to add it as special character to your keyboard using System preferences, Language and Text, and assign it to your keyboard.
Did I mention you can find it in the Character viewer, and copy it from there in the Special character keyboard setting. I used the alt+shift+o for it, but you can choose any combination you want to create it in text documents.
This is a sample how it looks in my notes.
The only way to have that character in Gill Sans is to add it using a font editor. Whether the font license would allow that for the kind of use envisaged I don't know. Common font editors are FontLab, FontForge, RoboFont, Type, and Glyphs.
o macron is Not present in my Gill Sans Light either, at least when I checked it via FontBook > Preview > Repertoire.