[HarfBuzz] Why harfbuzz doesn't handle ligature carets itself?

[Khaled Hosny]

On Fri, Dec 14, 2018 at 07:00:43PM +0330, Ebrahim Byagowi wrote:
> Hey there, just occurred to me this [hopefully not deeply incorrect] why
> harfbuzz itself doesn't handle ligature carets, distributing the ligature
> cluster advance with ignorable clusters followed by using GDEF/lcar info,
> with falling back to equal dividing?

The current API does not allow for such fallback as it takes in glyph
index only, but you need text string of the ligature. You will also need
to do grapheme clusters segmentation which (IIRC) HarfBuzz does not
currently fully handle.

Regards,
Khaled