Custom symbol with lower- and uppercase glyphs?

[Jaakko (Jaakko Haaparanta)]

Might be a newbie question but is there a way to create a custom character that has both upper and lowercase glyphs? Or is there a way to add a lowercase character for a existing glyph, like for example ampersand (Don’t ask why)?

[TimAhrens]

I think the “lowercase” version of any character is best implemented via the onum (oldstyle figures) feature. After all, oldstyle figures are lowercase numbers as well. So, name your glyph ampersand.osf and Glyphs will create the feature for you (you need to push the button in the font info, though). It will only be available in OpenType-enabled applicartions, though.

Alternatively, you can draw the lowercase ampersand in the normal ampersand glyph and the uppercase version as ampersand.case. This might be the even cleaner implementation but it depends on how your font will be used.

[mekkablue (Rainer Erich Scheichelbauer)]

Or, the other way around, this is what case is intended for:

Shifts various punctuation marks up to a position that works better with all-capital sequences or sets of lining figures; also changes oldstyle figures to lining figures. By default, glyphs in a text face are designed to work with lowercase characters. Some characters should be shifted vertically to fit the higher visual center of all-capital or lining text. Also, lining figures are the same height (or close to it) as capitals, and fit much better with all-capital text.

Quote taken from the description in the Layout Tag Registry.

[Jaakko (Jaakko Haaparanta)]

Thanks for pointing me in the right direction. It seems I still need to do some more studying on the subject.

This article helped a lot understanding OpenType substitution features.