[HarfBuzz] On fallback shaping and future directions

Behdad Esfahbod behdad at behdad.org
Tue Nov 23 10:44:38 PST 2010


[Adding the list back to the CC]

On 11/22/10 18:38, Butrus Damaskus wrote:
>>  - ZWNJ/ZWJ, etc:  Pango also used to remove these characters from the glyph
>> stream.  Not actually removing them in fact, but replacing them with "empty"
>> glyphs.  That's ok for Arabic, but in general we should handle those two
>> special characters much better.  In particular, the OpenType engine should
>> simply ignore ZWJ when forming ligatures.
> 
> There are fonts that use ZWJ for forming rare ligatures.
> See e.g: http://www.sbl-site.org/Fonts/SBLHebrewUserManual1.5x.pdf
> 
> So replacing ZWJ/ZWNJ _glyphs_ with "empty" glyph is OK, but not
> before they (or at least ZWJ) are subject of GSUB substitutions!
> 
> (BTW http://bugzilla.gnome.org/show_bug.cgi?id=635391)

Right.  Thanks for bringing this up.  I commented on the bug.

behdad



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