[HarfBuzz] the feature tag support in harfbuzz

[Behdad Esfahbod]

On 05/28/2012 09:55 PM, Akira TAGOH wrote:
>> >  - Add fontconfig elements for turning features on / off.  Not sure about the
>> > best format.  Maybe just support turning on?
>
> Maybe. at least for those feature tags, they conflict each other. so
> that should works enough. if there are any requirements to turn off -
> for example, it's enabled by default in the font but one wants to
> disable the feature - we could think the way how to do that as needed.

Yes, that's mainly my thinking: the only feature I can imagine people will
legitimately may want to turn off would be 'liga', but even that, I can only
imagine being because of broken fonts.  So I guess the question is to what
extent do we want to let people fixup for broken fonts using this features.

behdad