I want to include a feature, that allows live-stretching a character by typing it repeatedly.
Double-o should remain untouched, but from the third “o” on, it should be substituted by its stretched versions (o.001, o.002, o.003):
sub o o o o o by o.003;
sub o o o o by o.002;
sub o o o by o.001;
Does it make sense to use the dlig feature here?
Plus what I want to achieve is that o.001 consists of one single “o”, and not “ooo” when copy/pasting the text.
Can you post a screenshot of your stretched design? Perhaps there is a better solution than endless ligatures.
That is not possible. The OpenType feature is applied on the glyphs, and has no influence on the characters.
left is the standard o, right the most stretched alternative with width 1800. 11 steps in between. same applies to 6 more characters, so this would not end up in a flood of ligatures.
Depends where you like to use it, but you could try to use a variable font for this kind of stuff.