[HarfBuzz] [docs][question] Emoji "shaping", etc.

[Martin Hosken]

Dear Nathan,

> Kind of a high-level question about describing HB functionality....
> 
> Would you consider the handling of emoji variation-selector sequences to be
> "shaping", or some other operation?
> 
> Feels like kind of a gray area to me; when it comes to describing what
> HarfBuzz does and what the use cases are that developers need it for,
> though, it's important to get it right. So I'd like to know what the
> consensus is....

Not for me, since it doesn't involve either a glyph to glyph mapping or the positioning of any glyphs.

But: creating ligatures, kerning (of any kind), getting combining marks positioned correctly, all are. So handling the skin tone letters to give different kinds of faces in emoji is shaping.

> [Related question also applies to handling the MATH table -- AIUI, HarfBuzz
> leaves math layout to others higher up in the stack, so I wouldn't call
> math-table support "math shaping", but other people may see it
> differently...]

Harbfuzz need not be the only shaping processor :) But at that point I see hairs splitting.

Yours,
Martin