Re: Justification (was Re: Unicode Font Maker)

["Mete Kural" <metek at touchtonecorp dot com>]

Hello Gregg,

By <TATWEEL> you mean the Unicode codepoint 0640 Arabic Tatweel? Using 0640 Tatweel in Arabic text on a regular basis is a non-starter. Tatweel is a typographic feature, it shouldn't be encoded in raw text. But a rendering engine could perhaps make use of it by pre-processing raw encoded text and inserting tatweels where desired before sending it to be rendered. An encoder should not have to encode Tatweels on a regular basis in Arabic text.

Regards,
Mete

---------- Original Message ----------------------------------
From: Gregg Reynolds <gar at arabink dot com>
Reply-To: General Arabization Discussion <general at arabeyes dot org>
Date:  Wed, 03 Aug 2005 11:02:03 -0500

>Thomas Milo wrote:
>> Meor Ridzuan Meor Yahaya wrote:
>> 
>> 
>>>Do you have ideas on arabic justification that you don't mind sharing
>>>with us?
>> 
>> 
>> Yes. Considering keshide or madd a justification aid does not do justice to
>> the art of calligraphy or typesetting. Keshide is an esthric device, not a
>> trick. It serves to change the general appearance of text, in other words,
>> you use them or you don't. If used, in calligraphy and well-executed
>> typesetting, keshide is bound to many contextual constraints, which, just
>> like the ligature system, are not generally know among computer
>> enthousiasts, with devastating consequences for the Islamic art of text
>> composition.
>> 
>> To sum it up: justification can very well be achieved by subtle variation in
>> intra-word and inner-word spacing. Only as a last resort keshide should be
>> used for justification.
>> 
>
>Here's my solution:  define <TATWEEL> to mean "this place is a candidate 
>for extension of the line, regardless of coloration", such that it takes 
>on color based on context.  E.g. <k><tatweel><t><b> means the positive 
>(inked) space between <k> and <t> (i.e. the tiestroke) may be extended. 
>  <d><tatweel><w><r> means the negative space (whitespace) between <d> 
>and <w> may be extended.  The relative extent of such stretching would 
>be set by typesetting policy in the software.  Then there are four 
>groups of extension candidates: ordinary inter-word negative space, 
>explicitly specified stretch candidates (using tatweel), and ordinary 
>intra-word positive (black) and negative (white) space.  It's up to the 
>composition system to set policy regarding how extra space is 
>distributed among these categories.  This is pretty much how the TeX 
>justification algorithm works.
>
>-gregg
>
>

--
Mete Kural
Touchtone Corporation
714-755-2810
--