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

[Rob T]

I checked and the largest subtable has 40k entries. I don't notice a problem 
but was curious if converting .ttf with GPOS to .ttf with 'kern' would retain 
all 200k kern pairs. It seems it does. Presumably kerning functions exactly the 
same in either format from the user perspective?

So this is good news until the purveyors of WPS Office etc. get round to 
implementing GPOS support.
On Jul 28 2021, at 5:26 pm, Werner LEMBERG <wl@gnu.org> wrote:
>
> > I am trying to use Adobe Source Serif in WPS Office on Linux. I
> > notice that it ignores kerning pairs in the .otf version. In the
> > .ttf version it also ignores kerning pairs. This is because WPS
> > doesn't support GPOS kerning. However, if I open either of the
> > original fonts in fontforge and export as .ttf with a 'kern' table
> > then kerning is activated in WPS Office.
>
> Well, kerning in the GPOS table exists since 20 years or so...
> > I notice that there are 200,000 kern pairs in 15 subtables in my
> > generated fonts. What is the limit of entries that freetype can
> > handle?
>
> FreeType handles up to 32 subtables (with up to 65k entries each).
> This is an arbitrary limit as a protection against malformed fonts.
> Did you notice a problem?
>
>
> Werner