ntg-context - mailing list for ConTeXt users
 help / color / mirror / Atom feed
* can Context render complex scripts?
@ 2010-06-11  7:14 Michael Saunders
  2010-06-11  7:49 ` Khaled Hosny
  2010-06-13 14:59 ` Hans Hagen
  0 siblings, 2 replies; 15+ messages in thread
From: Michael Saunders @ 2010-06-11  7:14 UTC (permalink / raw)
  To: ntg-context

My first experiments aren't going well.  For example:

using the free font, BNBDOT0N.ttf, from  Deutsche Welle here:
http://www.dw-world.de/dw/article/0,,3219221,00.html

and the following typescript, "type-bidisha.tex":

\starttypescript [serif] [dwbangla]
   \definefontsynonym[DWbangla][name:BNBIDISHAOpentypeNormal][features=body]
\stoptypescript

\starttypescript [serif] [dwbangla]
   \definefontsynonym[Serif][DWbangla][features=body]
\stoptypescript

\starttypescript [dwbangla]
   \definetypeface [dwbangla] [rm] [serif] [dwbangla] [default]
[script=beng,features=body]
\stoptypescript

I try the following test:


\definefontfeature[default][mode=node,language=dflt,script=latn,kern=yes,liga=yes,tlig=yes,trep=yes]
\definefontfeature[body][default][mode=node,script=latn,onum=yes,pnum=yes,calt=yes,protrusion=quality,expansion=quality]
%just to be sure:
\definefontfeature[indic][body][nukt=yes,akhn=yes,rphf=yes,blwf=yes,half=yes,pstf=yes,vatu=yes,pres=yes,blws=yes,abvs=yes,psts=yes,	haln=yes,blwm=yes,abvm=yes,dist=yes]
\usetypescriptfile[type-bidisha]

\starttypescript [MTbook]
\definetypeface [dwbangla] [rm] [serif] [dwbangla] [default]
[script=beng,language=ben,features=body]
\stoptypescript

\def\bengali#1{{\switchtobodyfont[dwbangla]\addff{indic}\language[ben]#1}}

\usetypescript[MTbook]

\starttext
\bengali{সত্যজিৎ রায়}
\stoptext


"সত্যজিৎ" isn't rendered correctly in the output---after a the first
two characters, things go wrong.  Yet, with the same font, it is
rendered correctly everywhere else I look in windows---notepad,
Firefox, TexnicCenter, etc., etc.  To see what a correct rendering
should look like, google "সত্যজিৎ রায়" or see here:

http://bn.wikipedia.org/wiki/%E0%A6%B8%E0%A6%A4%E0%A7%8D%E0%A6%AF%E0%A6%9C%E0%A6%BF%E0%A7%8E_%E0%A6%B0%E0%A6%BE%E0%A6%AF%E0%A6%BC

or here (first word in text, in bold):

http://i367.photobucket.com/albums/oo113/andbipul/All%20about%20JJ/JJ%20Torjoma%20Works/Work-11Post-1.jpg

I tried this with several other free and MS fonts (e.g., arial Unicode
MS) and got the same results.  Am I doing something wrong?
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-11  7:14 can Context render complex scripts? Michael Saunders
@ 2010-06-11  7:49 ` Khaled Hosny
  2010-06-13 14:59 ` Hans Hagen
  1 sibling, 0 replies; 15+ messages in thread
From: Khaled Hosny @ 2010-06-11  7:49 UTC (permalink / raw)
  To: mailing list for ConTeXt users

On Fri, Jun 11, 2010 at 02:14:12AM -0500, Michael Saunders wrote:
> My first experiments aren't going well.  For example:

AFAIK, there no Indic specific support yet, Hans will probably need more
information about Indic shaping, some test files, the expected output
etc.

Also, AFAIK, Indic support in OpenType is a bit messy, as there are two
specification by MS, one deprecating the other, and there are fonts in
the wild that implement this or that, there isn't any free
implementation of the new specification, BTW.

Digging MS typography site for more information would be a good start, I
guess.

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-11  7:14 can Context render complex scripts? Michael Saunders
  2010-06-11  7:49 ` Khaled Hosny
@ 2010-06-13 14:59 ` Hans Hagen
  2010-06-13 16:58   ` Michael Saunders
  1 sibling, 1 reply; 15+ messages in thread
From: Hans Hagen @ 2010-06-13 14:59 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: Idris Samawi Hamid, Michael Saunders

On 11-6-2010 9:14, Michael Saunders wrote:
> My first experiments aren't going well.  For example:
>
> using the free font, BNBDOT0N.ttf, from  Deutsche Welle here:
> http://www.dw-world.de/dw/article/0,,3219221,00.html

next time make a simple example .. you caniidentity features with

mtxrun --script font --info --list --file BNBDOT0N.ttf

anyhow, only one features is applied. It lookslike some gpos feature is 
not used.

\usemodule[fnt-20]

\definefontfeature
   [indic]
   [mode=node,analyze=yes,
    script=beng,language=dflt,
    % gsub
    abvs=yes,akhn=yes,blwf=yes,blws=yes,
    half=yes,nukt=yes,pstf=yes,psts=yes,rphf=yes,
    % gpos
    blwm=yes,abvm=yes]

\definefontsynonym[dwbangla][file:BNBDOT0N.ttf]

\starttext

     {\definedfont[dwbangla*indic] সত্যজিৎ রায় \par}

     \showotfcomposition
         {dwbangla*indic}
         {0}
         {সত্যজিৎ রায়}

\stoptext



-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 14:59 ` Hans Hagen
@ 2010-06-13 16:58   ` Michael Saunders
  2010-06-13 19:07     ` Hans Hagen
  0 siblings, 1 reply; 15+ messages in thread
From: Michael Saunders @ 2010-06-13 16:58 UTC (permalink / raw)
  To: ntg-context; +Cc: pragma, ishamid

> next time make a simple example .. you caniidentity features with
>
> mtxrun --script font --info --list --file BNBDOT0N.ttf
>
> anyhow, only one features is applied. It lookslike some gpos feature is not
> used.
>
> \usemodule[fnt-20]
>
> \definefontfeature
>  [indic]
>  [mode=node,analyze=yes,
>   script=beng,language=dflt,
>   % gsub
>   abvs=yes,akhn=yes,blwf=yes,blws=yes,
>   half=yes,nukt=yes,pstf=yes,psts=yes,rphf=yes,
>   % gpos
>   blwm=yes,abvm=yes]
>
> \definefontsynonym[dwbangla][file:BNBDOT0N.ttf]
>
> \starttext
>
>    {\definedfont[dwbangla*indic] সত্যজিৎ রায় \par}
>
>    \showotfcomposition
>        {dwbangla*indic}
>        {0}
>        {সত্যজিৎ রায়}
>
> \stoptext


I don't understand---are you saying this is supposed to work?  Is the
trick supposed to be using fnt-20 or in being careful not to turn on
unused features?  (To be on the safe side, since I was switching
between them in testing, I was turning on all the features Microsoft
calls Indic.)  I tried your example and, yes, one shaping looks
correct, but there was no reordering and now some of the characters
print out on top of each other (which is incorrect).  I tried the same
routine, using  fnt-20 and commenting out unused features, for some
other fonts:
Akaash:
http://www.nongnu.org/freebangfont/downloads.html
Bangla, from the University of Chicago:
http://salrc.uchicago.edu/resources/fonts/available/bengali/
and Arial Unicode MS  (standard on Windows),
and I got no improvement in their rendering in Context.  They work
fine in Notepad, Firefox, and TexnicCenter though, for example.

What am I missing?
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 16:58   ` Michael Saunders
@ 2010-06-13 19:07     ` Hans Hagen
  2010-06-13 19:15       ` Khaled Hosny
  2010-06-13 19:29       ` Michael Saunders
  0 siblings, 2 replies; 15+ messages in thread
From: Hans Hagen @ 2010-06-13 19:07 UTC (permalink / raw)
  To: Michael Saunders; +Cc: ntg-context, ishamid

On 13-6-2010 6:58, Michael Saunders wrote:
>> next time make a simple example .. you caniidentity features with
>>
>> mtxrun --script font --info --list --file BNBDOT0N.ttf
>>
>> anyhow, only one features is applied. It lookslike some gpos feature is not
>> used.
>>
>> \usemodule[fnt-20]
>>
>> \definefontfeature
>>   [indic]
>>   [mode=node,analyze=yes,
>>    script=beng,language=dflt,
>>    % gsub
>>    abvs=yes,akhn=yes,blwf=yes,blws=yes,
>>    half=yes,nukt=yes,pstf=yes,psts=yes,rphf=yes,
>>    % gpos
>>    blwm=yes,abvm=yes]
>>
>> \definefontsynonym[dwbangla][file:BNBDOT0N.ttf]
>>
>> \starttext
>>
>>     {\definedfont[dwbangla*indic] সত্যজিৎ রায় \par}
>>
>>     \showotfcomposition
>>         {dwbangla*indic}
>>         {0}
>>         {সত্যজিৎ রায়}
>>
>> \stoptext
>
>
> I don't understand---are you saying this is supposed to work?  Is the

well, i wrote: it looks like some pos feaure is not applied ...

> trick supposed to be using fnt-20 or in being careful not to turn on
> unused features?  (To be on the safe side, since I was switching

no, but turning them on makes tracing cumbersome

> between them in testing, I was turning on all the features Microsoft
> calls Indic.)  I tried your example and, yes, one shaping looks
> correct, but there was no reordering and now some of the characters
> print out on top of each other (which is incorrect).  I tried the same
> routine, using  fnt-20 and commenting out unused features, for some
> other fonts:

> What am I missing?

As Khaled mentioned ... are these proper otf fonts or do they rely on 
specific features in the microsoft engine?

Most opentype features are quite generic and should work ok but if 
something special is needed more info is needed.

Hans


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:07     ` Hans Hagen
@ 2010-06-13 19:15       ` Khaled Hosny
  2010-06-13 19:19         ` Khaled Hosny
  2010-06-13 19:41         ` Hans Hagen
  2010-06-13 19:29       ` Michael Saunders
  1 sibling, 2 replies; 15+ messages in thread
From: Khaled Hosny @ 2010-06-13 19:15 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: ishamid, Michael Saunders

On Sun, Jun 13, 2010 at 09:07:55PM +0200, Hans Hagen wrote:
> As Khaled mentioned ... are these proper otf fonts or do they rely
> on specific features in the microsoft engine?
> 
> Most opentype features are quite generic and should work ok but if
> something special is needed more info is needed.

IIRC, there is a bit of engine level glyph reordering involved with
Indic rendering.

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:15       ` Khaled Hosny
@ 2010-06-13 19:19         ` Khaled Hosny
  2010-06-13 19:28           ` Khaled Hosny
  2010-06-13 19:41         ` Hans Hagen
  1 sibling, 1 reply; 15+ messages in thread
From: Khaled Hosny @ 2010-06-13 19:19 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: ishamid, Michael Saunders

On Sun, Jun 13, 2010 at 10:15:35PM +0300, Khaled Hosny wrote:
> On Sun, Jun 13, 2010 at 09:07:55PM +0200, Hans Hagen wrote:
> > As Khaled mentioned ... are these proper otf fonts or do they rely
> > on specific features in the microsoft engine?
> > 
> > Most opentype features are quite generic and should work ok but if
> > something special is needed more info is needed.
> 
> IIRC, there is a bit of engine level glyph reordering involved with
> Indic rendering.

Here is a tugboat article with more details:
http://www.tug.org/TUGboat/Articles/tb23-1/rajkumar.pdf

Though it might not be up to date, but it gives a good overall idea
about the issue.

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:19         ` Khaled Hosny
@ 2010-06-13 19:28           ` Khaled Hosny
  0 siblings, 0 replies; 15+ messages in thread
From: Khaled Hosny @ 2010-06-13 19:28 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: ishamid, Michael Saunders

On Sun, Jun 13, 2010 at 10:19:50PM +0300, Khaled Hosny wrote:
> On Sun, Jun 13, 2010 at 10:15:35PM +0300, Khaled Hosny wrote:
> > On Sun, Jun 13, 2010 at 09:07:55PM +0200, Hans Hagen wrote:
> > > As Khaled mentioned ... are these proper otf fonts or do they rely
> > > on specific features in the microsoft engine?
> > > 
> > > Most opentype features are quite generic and should work ok but if
> > > something special is needed more info is needed.
> > 
> > IIRC, there is a bit of engine level glyph reordering involved with
> > Indic rendering.
> 
> Here is a tugboat article with more details:
> http://www.tug.org/TUGboat/Articles/tb23-1/rajkumar.pdf
> 
> Though it might not be up to date, but it gives a good overall idea
> about the issue.

And MS page:
http://www.microsoft.com/typography/otfntdev/indicot/features.aspx

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:07     ` Hans Hagen
  2010-06-13 19:15       ` Khaled Hosny
@ 2010-06-13 19:29       ` Michael Saunders
  2010-06-13 19:50         ` Khaled Hosny
  1 sibling, 1 reply; 15+ messages in thread
From: Michael Saunders @ 2010-06-13 19:29 UTC (permalink / raw)
  To: Hans Hagen; +Cc: ntg-context

> As Khaled mentioned ... are these proper otf fonts or do they rely on
> specific features in the microsoft engine?

They all carry the .ttf extender.  Arial Unicode MS is clearly True
Type.  I've seen some of the free fonts widely described as Open Type,
but they are all amateur products---maybe they don't comply with the
standard properly.

If True Type fonts won't work correctly without an external engine and
Context can't harness an external engine, then it looks like I will
just have to wait for a more modern font to come along.

Thanks for the article, Khaled.
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:15       ` Khaled Hosny
  2010-06-13 19:19         ` Khaled Hosny
@ 2010-06-13 19:41         ` Hans Hagen
  2010-06-13 20:07           ` Idris Samawi Hamid ادريس   سماوي حامد
  1 sibling, 1 reply; 15+ messages in thread
From: Hans Hagen @ 2010-06-13 19:41 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: ishamid, Michael Saunders

On 13-6-2010 9:15, Khaled Hosny wrote:
> On Sun, Jun 13, 2010 at 09:07:55PM +0200, Hans Hagen wrote:
>> As Khaled mentioned ... are these proper otf fonts or do they rely
>> on specific features in the microsoft engine?
>>
>> Most opentype features are quite generic and should work ok but if
>> something special is needed more info is needed.
>
> IIRC, there is a bit of engine level glyph reordering involved with
> Indic rendering.

i remember seeing that mentioned at some place but forgot the details

the interesting question then is .. where does one draw the line between 
engine and clever fonts


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:29       ` Michael Saunders
@ 2010-06-13 19:50         ` Khaled Hosny
  2010-06-13 20:08           ` Hans Hagen
  0 siblings, 1 reply; 15+ messages in thread
From: Khaled Hosny @ 2010-06-13 19:50 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: Hans Hagen

On Sun, Jun 13, 2010 at 02:29:40PM -0500, Michael Saunders wrote:
> > As Khaled mentioned ... are these proper otf fonts or do they rely on
> > specific features in the microsoft engine?
> 
> They all carry the .ttf extender.  Arial Unicode MS is clearly True
> Type.  I've seen some of the free fonts widely described as Open Type,
> but they are all amateur products---maybe they don't comply with the
> standard properly.
> 
> If True Type fonts won't work correctly without an external engine and
> Context can't harness an external engine, then it looks like I will
> just have to wait for a more modern font to come along.

OpenType (just ignore file extension for the moment) is a rather dump
standard in the sense that it requires the engine to have some knowledge
about the writing system at hand. Take Arabic as an example, the engine
need to know about the rules of Arabic shaping, what are letters are
dual joining, what are right joining only etc. and then apply OpenType
features conditionally on those characters, without that knowledge, no
OpenType engine is capable for rendering Arabic, and the same is true for
any other complex script.

On the other hand, there is AAT and Graphite fonts, that are implemented
in a more generic way, where the engine has no particular knowledge about
any writing system and all the rules are embedded into the font. Though
this seems a bit smarter, it makes the task of building a font very
complex and tedious since the rules have to be implemented again and
again in each font, also type designers are not programmers and asking
them to do such complex tasks is impractical, for example you can count
all AAT fonts that produced outside Apple, the makers of the technology,
on one hand, now even Apple is moving to OpenType.

So, what we have here is that ConTeXt has no special knowledge about
Indic scripts, and thus it will not apply the feature properly according
the linguistic rules. So, instead of waiting for a "more modern font to
come along" (which unlikely to happen any time soon, giving how much the
industry have invested into OpenType, and the apparent failure of AAT),
just try to reach more people in the Indic community and come out with a
clear specification and tests that Hans can implement.

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:41         ` Hans Hagen
@ 2010-06-13 20:07           ` Idris Samawi Hamid ادريس   سماوي حامد
  2010-06-14  1:21             ` Michael Saunders
  0 siblings, 1 reply; 15+ messages in thread
From: Idris Samawi Hamid ادريس   سماوي حامد @ 2010-06-13 20:07 UTC (permalink / raw)
  To: mailing list for ConTeXt users, Hans Hagen; +Cc: Michael Saunders

Hi,

On Sun, 13 Jun 2010 13:41:38 -0600, Hans Hagen <pragma@wxs.nl> wrote:

> the interesting question then is .. where does one draw the line between  
> engine and clever fonts

contextual analysis in Arabic provides an example: init, medi, and fina  
provide the gsub's, the engine has to know the rules/conditions under  
which to apply each of those three. Eg, VOLT Proofing tool will NOT do  
contextual analysis, only implement the selected lookups. Something  
similar applies to Indic of course, but someone has to provide the  
framework of rules. The MS pages Khaled sent are a good place to start,  
and a user willing to make examples with explanations etc...

That is, given all gsub and gpos routines needed by a given language, what  
minimal additional information does the engine need to know? In Arabic,  
one needs contextual analysis: if a letter occurs at the beginning of a  
string, choose the init gsub routine etc.

The bad thing about Uniscribe is that it adds too much information and  
"spell-checking", restricting typesetting possibilities.

In any case, someone interested has to research/provide the details for  
Indic.

Best wishes
Idris
-- 
Professor Idris Samawi Hamid, Editor-in-Chief
International Journal of Shi`i Studies
Department of Philosophy
Colorado State University
Fort Collins, CO 80523

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 19:50         ` Khaled Hosny
@ 2010-06-13 20:08           ` Hans Hagen
  0 siblings, 0 replies; 15+ messages in thread
From: Hans Hagen @ 2010-06-13 20:08 UTC (permalink / raw)
  To: Khaled Hosny; +Cc: mailing list for ConTeXt users

On 13-6-2010 9:50, Khaled Hosny wrote:

> So, what we have here is that ConTeXt has no special knowledge about
> Indic scripts, and thus it will not apply the feature properly according
> the linguistic rules. So, instead of waiting for a "more modern font to
> come along" (which unlikely to happen any time soon, giving how much the
> industry have invested into OpenType, and the apparent failure of AAT),
> just try to reach more people in the Indic community and come out with a
> clear specification and tests that Hans can implement.

from the ms pages it looks like we should split the chars (sequences) 
into components and after that the oft features can be applied; as the 
spec is somewhat fuzzy i'll just wait till precise specs are given

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-13 20:07           ` Idris Samawi Hamid ادريس   سماوي حامد
@ 2010-06-14  1:21             ` Michael Saunders
  2010-06-14  7:57               ` Hans Hagen
  0 siblings, 1 reply; 15+ messages in thread
From: Michael Saunders @ 2010-06-14  1:21 UTC (permalink / raw)
  To: ntg-context

> OpenType (just ignore file extension for the moment) is a rather dump
> standard in the sense that it requires the engine to have some knowledge
> about the writing system at hand.
...
> So, what we have here is that ConTeXt has no special knowledge about
> Indic scripts, and thus it will not apply the feature properly according
> the linguistic rules.

It seems to me that, since Hans can't be expected to write special
code for dozens of Indic scripts, let alone for every script in the
world, the pragmatic solution would be a method for Context to harness
external engines (ICU, Pango, Graphite, Uniscribe, or whatever).  If
that's not possible, or if he doesn't want to do it, or until he is
able to work with scholars on each special case, programs like Notepad
will be able to do something that Context can't.   As a casual user,
it's not an urgent need for me.  I had read that Aleph functionality
had been integrated into LuaTeX (though I never found anything very
detailed about that) and thought that everything was okay.  I assume
that Luatex/Context or some future TeX  will have this functionality
someday, however it's implemented.  I'll just keep watching.
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: can Context render complex scripts?
  2010-06-14  1:21             ` Michael Saunders
@ 2010-06-14  7:57               ` Hans Hagen
  0 siblings, 0 replies; 15+ messages in thread
From: Hans Hagen @ 2010-06-14  7:57 UTC (permalink / raw)
  To: mailing list for ConTeXt users; +Cc: Michael Saunders

On 14-6-2010 3:21, Michael Saunders wrote:
>> OpenType (just ignore file extension for the moment) is a rather dump
>> standard in the sense that it requires the engine to have some knowledge
>> about the writing system at hand.
> ....
>> So, what we have here is that ConTeXt has no special knowledge about
>> Indic scripts, and thus it will not apply the feature properly according
>> the linguistic rules.
>
> It seems to me that, since Hans can't be expected to write special
> code for dozens of Indic scripts, let alone for every script in the
> world, the pragmatic solution would be a method for Context to harness
> external engines (ICU, Pango, Graphite, Uniscribe, or whatever).  If
> that's not possible, or if he doesn't want to do it, or until he is
> able to work with scholars on each special case, programs like Notepad
> will be able to do something that Context can't.   As a casual user,
> it's not an urgent need for me.  I had read that Aleph functionality
> had been integrated into LuaTeX (though I never found anything very
> detailed about that) and thought that everything was okay.  I assume
> that Luatex/Context or some future TeX  will have this functionality
> someday, however it's implemented.  I'll just keep watching.

if you want to use external engines ... use xetex instead of luatex

the whole idea behind luatex is that we have a configureable and 
programmable engine ... doing some script is not so much an issue (and 
we can do it more flexible once we have the machinery in place) but 
information is needed ... also, as we want tex cum suis to be flexible 
on the one hand and stable on the other, depending on hidden or fuzzy 
features in en uniscribe engine might not be the best idea

in the oriental tex project we've spend quite some time on high quality 
arabic and i'm sure that we could not have come this far if we had wrote 
the code from scratch (all this font technology is not as open as the 
name suggest) ... also, there's more in mkiv than shown so far (esp in 
that area) for those experiments


Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________


^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2010-06-14  7:57 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-06-11  7:14 can Context render complex scripts? Michael Saunders
2010-06-11  7:49 ` Khaled Hosny
2010-06-13 14:59 ` Hans Hagen
2010-06-13 16:58   ` Michael Saunders
2010-06-13 19:07     ` Hans Hagen
2010-06-13 19:15       ` Khaled Hosny
2010-06-13 19:19         ` Khaled Hosny
2010-06-13 19:28           ` Khaled Hosny
2010-06-13 19:41         ` Hans Hagen
2010-06-13 20:07           ` Idris Samawi Hamid ادريس   سماوي حامد
2010-06-14  1:21             ` Michael Saunders
2010-06-14  7:57               ` Hans Hagen
2010-06-13 19:29       ` Michael Saunders
2010-06-13 19:50         ` Khaled Hosny
2010-06-13 20:08           ` Hans Hagen

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).