[luatex] otf fonts (ligatures, cache, etc.)
taco at elvenkind.com
Tue Apr 7 08:48:10 CEST 2009
Elie Roux wrote:
> Karl Berry a écrit :
>> for example 1/4 (I'm sure there are more pertinent examples
>> For example, "ffi" and "ffl" are standard ligatures in English.
> In most latine languages too, but these are special, as the mechanism
> is: ffi -> f_fi -> f_f_i, and you can't have this mechanism on 1/4,
> because 1_/ does not exist, where f_f does.
In an opentype font, you can have things like
f f i -> f_f_i
in a single lookup step and the font would be perfectly legal even
if it didn't have an f_f glyph at all.
TeX's ligature building can't do that, it absolutely has to go
through an "f_f i" stage. This means that if you want a fully
reliable font system, you will have to do node list processing
even for simple ligatures (and definitely for 'frac').
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