[HarfBuzz] disabling Arabic shaping when direction is vertical

[Behdad Esfahbod]

On 15-04-23 01:35 PM, Jonathan Kew wrote:
> 
>> Probably should do for Indic as well.
> 
> I'm not entirely sure about this (or SEAsian, etc). The CSS writing modes spec
> specifically mentions "horizontal cursive scripts (such as Arabic)", but I
> don't think Indic scripts fit this category. Examples are hard to find, but I
> suspect the appropriate rendering of Indic and similar scripts with vertical
> direction and upright glyph orientation would be to stack by grapheme
> clusters, or something along those lines - but we'd still need shaping
> features such as pre-vowel reordering, reph formation, etc.

Agreed.  Lets not touch them now.  It might be possible to implement that with
rather minor modifications.

-- 
behdad
http://behdad.org/