[XeTeX] wrong kerning and slow processing with xelatex in texlive 2010

[Jonathan Kew]

On 13 Oct 2010, at 14:10, Vadim Radionov wrote:

> I finally found the explanation. Mea culpa, it was in the kerning in
> the font. All 3 lookup tables contained kerning -50 for small caps
> Cyrillic `t' and `a', and the was another one of -60 in kerning
> classes, which gave the total of -210.
> 
> I'm not sure if it is allowed and what should be the default behavior
> of typesetting program -- to add them of to use the last.

Are all those lookup tables assigned to the 'kern' feature within the same script and language system? If so, then they're cumulative. If the lookups are each assigned to a different script/language, then they shouldn't all be applied at the same time.

JK


> If it is
> stated somewhere and you can point me to it, i will complain to my
> font vendor. And of course I will check for such cases myself and wipe
> out extra kerning.