Quote:
Originally Posted by lumpynose
How do they know which character sequences to convert to a ligature? Are they assuming the standard ones, e.g., fl, fi, etc.? Some fonts have nonstandard ligatures, for example, I saw one that had a ligature for st where there was a connector at the top of the s going to the top of the t.
|
If the font is correctly compiled, there will be a ligature substitution table inside the GSUB table. This can be read to find which ligatures the font supports. In the st ligature you mentioned, it should be found in the substitution table (Libertine does have this table and ligature).
As for what constitutes a "standard" ligature? That is more of a religious argument than anything else. There have been many ligatures used in typography over the centuries. For instance, a lower case f followed by a full stop has a ligature in some fonts. Other arguments would involve such words as selfless where the fl ligature should not be used as it crosses the boundary between self and less (morpheme boundary).