[XeTeX] weird kerning with GFS Didot's italic face

[Jonathan Kew]

On 6 Jul 2006, at 9:58 pm, Pablo Rodríguez wrote:

> Jonathan Kew wrote:
>> On 6 Jul 2006, at 8:23 pm, Pablo Rodríguez wrote:
>>> Is there no way to switch GPOS kerning for a concrete font (or  
>>> for all
>>> fonts in a document) using fontspec or XeTeX?
>>
>> It's enabled by default (if present in the font); you can disable it
>> by specifying the "-kern" tag in the \font declaration, thus:
>>
>> 	\font\nokerndidot = "GFS Didot:-kern" at 12pt
>>
>> Fontspec doesn't seem to have a predefined option for this (how about
>> it, Will?!), but you can declare one; I think the form would be
>> something like this (untested):
>>
>> 	\newfontfeature{NoKerning}{-kern}
>> 	\setromanfont[NoKerning]{GFS Didot}
>
> Thanks, Jonathan, it worked fine, if GPOS kerning is not applied.
>
> BTW, is there another kerning in OpenType fonts other than GPOS?

The font might also contain a separate 'kern' table (a pre-OpenType  
table format), but OpenType-aware applications are generally expected  
to ignore this and apply kerning based on the GPOS 'kern' feature  
instead. I don't believe xetex will currently apply an old-style  
'kern' table at all; it only supports the OpenType feature.

JK