[HarfBuzz] Disabling OT features for ranges

[Behdad Esfahbod]

On 02/19/2013 09:40 AM, Lóránt Pintér wrote:
> Hi,
> 
> I'm trying to disable some OpenType features while shaping. I'm trying to
> shape "VAV VAV" and disable kerning for the first three characters.
> 
> If I don't set any features, kerning is on for the whole string: OK, this is
> what I expect
> If I set "+kern[4:7]", I get what I want: the first "VAV" is not kerned, the
> second is: OK
> *If I set "-kern[0:3]", I get kerning disabled for the whole string: NOT what
> I expect*
> *If I set "+kern", "-kern[0:3]", I get kerning disabled for the whole string:
> NOT what I expect*
> If I set "+kern[0:8]", "-kern[0:3]", I get what I want: the first "VAV" is not
> kerned, the second is: OK
> 
> So "+/-kern[x:y]" disables the kerning for the rest of the input unless I
> specify the whole range with "+kern[0:end]" first. I find it a bit
> contra-intuitive. Is this how it should work?

As Jonathan pointed out already, this was surprisingly broken and no one ever
noticed until now!  But we fixed it last week.

-- 
behdad
http://behdad.org/