[XeTeX] Ligatures

[Khaled Hosny]

On Wed, Jun 19, 2013 at 01:49:26PM +0200, Jean-Claude Raoult wrote:
> Le 19/06/2013 12:23, Khaled Hosny a écrit :
> >On Sun, Jun 02, 2013 at 11:53:00AM +0200, Jean-Claude Raoult wrote:
> >>The documentation is clear, for people using LaTeX or rather XeLaTeX.
> >Presumably because you were reading LaTeX oriented documentation? XeTeX
> >documentation itself documents the low level primitives and is macro
> >package neutral, though it is a bit anæmic.
> >
> >>I tried to adapt the doc, and write
> >>\font\truc="Linux Libertine O:mapping=tex-text:Ligatures=RareLigatures"
> >>or instead of RareLigatures: Rare Ligatures or Historical. Nothing worked.
> >OpenType features are accessed using 4-letter tag names, documenting
> >those tags is beyond XeTeX documentation since they are part of the
> >OpenType standard:
> >
> >	http://www.microsoft.com/typography/otspec/featurelist.htm
> >
> >XeTeX just passes whatever tag you give to the OpenType layout engine.
> >
> >Regards,
> >Khaled
> 
> Thank you. This is just what I needed. Incidentally, the tag +liga
> yielding ligatures for fi, ff, fl, ffi and ffl is the default.
> It shoul be disabled for small caps:
> \font\sc='Libertine Capitals O:-liga:mapping=tex-text"
> is better. Otherwise, definition and even theorem look strange.

Since the engine knows nothing about such smallcaps fonts, it is left to
the user to select/deselect features as appropriate. I’d consider this a
font bug too, if it is a smallcap font then it shouldn’t have
f-ligatures at all.

Regards,
Khaled