Re: Ligatures

[Clément Pit-Claudel]

On 18/05/2020 15.19, Pip Cet wrote:
> So such clusters would be marked as atomic? I like Stefan's proposal,
> and maybe it's what LibreOffice actually does: at large font sizes,
> the horizontal division of "subglyphs" seems off.

Yup, that's what Firefox and LibreOffice do.

>>> If Harfbuzz could tell us more precisely how to divide the glyph into
>>> subglyphs, we could do a better job, of course.
>>
>> I don't think it's possible because AFAIK fonts don't store this
>> information.
> 
> Well, they should!

They can, but few do (the LigatureCaretList subtable within the GDEF table)

>> It should be possible, of course, to have a private
>> database of such offsets, but I don't really see how it could work in
>> general.
> 
> And this is where it gets back to "let's not hardcode the dependency
> on Harfbuzz and FreeType, because other backends might actually give
> us the information we need".

Harfbuzz can give us this info: hb_ot_layout_get_ligature_carets