[scribus] Indic Support

[Pierre Marchand]

Vous (Gora Mohanty) avez écrit :
> I think that Harfbuzz should definitely be the longer-term target.> My only 
> fear is that the longer-term keeps getting longer and longer. ICU is here,
> and works now. 

100% agree

> My impression from talking to avox was that ICU/Pango does 
> not quite meet the need for the details that Scribus needs. 

Exact. But still we can get something interesting. What’s embarassing with 
shapers is that they do not let user insert arbitrary OT features. But I 
imagine that it’s an acceptable limitation compared to today’s state.
For Indic it would be some dilemnia as in choosing between automatically 
shaping text and processing a stylistic set. But as shaping for at East-Asian 
scripts is not an option you won’t take advantage of possible extra features.

> However, if it 
> is adequate enough for shaping, then we can volunteer to help integrate
> ICU.

Integrating ICU per se is not that great deal (modulo some really fun problems 
such as cursor positionning in clusters :-) or hyphenation in ligatures 
etc.). Problem is more about architecture of Scribus text layout engine 
itself. My initial idea was to offer shaping of text chunks as a font service 
(and it’s how I did it)(it implies something like a font shell to get/set 
script, language & features, etc.) but Andreas is not very excited with this. 
I guess we’ll discuss all that again after 135 release, which is the main job 
atm. 

> I am not sure what OpenType handling needs Scribus has, nor of the 
> current state of the Harfbuzz OpenType module. Would libotf from m17n be a
> possible interim solution if Harfbuzzz OT is still under development?

In reverse order :) 
M17N is talking about migrate from libotf to Harfbuzz for OT processing.

If Harfbuzz shapers collection is not mature enough in Harfbuzz git repo. (as 
used in Qt & Pango trees they seem to work not so bad)(e.g. I’ve noticed that 
if it does crash often with devanagari, arabic works fine), the Harbuzz 
OpenType Processor (I mean the submodule dedicated to applying OT features to 
an HB_Buffer) is solid, using it in fontmatrix without problem.

Why OpenType support is important? For East-Asian or Arabic shaping Scribus 
could just use ICU or HB without bother about what’s inside. But OpenType 
fonts also embed important features for latin scripts which can hardly be 
handled by a shaper engine --- e.g. onum, hist, dlig, smcp, etc. not to 
mention more stylish features, in short foundries have put in OT features 
what was before in expert sets.


-- 
Pierre Marchand