Re: Maximum length of 'kern' table supported in .ttf?

[Rob T]

Unfortunately I noticed that creating an old style 'kern' table with 200k 
entries gives incorrect kerning in WPS Office, for example the kern between A 
and V reduces the width between A and V but not by as much as the GPOS version 
does in a different application. As my subtables are all under 64k, this seems 
to be a problem with the units not being translated properly from GPOS to kern? 
i.e. all the kerning happens, but the letters are not moved as close together 
as they should be.

Also, is this error relevant to Freetype?
"Note: On Windows many apps can have problems with this font's kerning, because 
60194 of its glyph kern pairs cannot be mapped to unicode-BMP kern pairs (eg, 
they have a Unicode value of -1) To avoid this, go to Generate, Options, and 
check the "Windows-compatible "kern" option"
On Jul 29 2021, at 5:49 am, Werner LEMBERG <wl@gnu.org> wrote:
>
> > Presumably kerning functions exactly the same in either format from
> > the user perspective?
>
> Not really, since 'GPOS' is much more powerful. For example, you can
> disable, say, the kerning between 'f' and 'ı' for Turkish. On the
> other hand, data in the 'kern' table can't be handled specially for
> certain scripts and/or languages.
>
> However, in its most basic, 'classic' functionality the 'kern' and
> 'GPOS' tables do the same thing.
>
>
> Werner