Bug with "Adobe Arabic" font kerning

Bug with "Adobe Arabic" font kerning

[Khaled Hosny]

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The font seems to have a buggy (too big) GPOS kerning table (it does cause
fontforge to hang writing the font). If 'kern' is set to 'yes', I get this
error:

...text/tex/texmf-context/tex/context/base/node-inj.lua:62:
attempt to index local 'kb' (a nil value)

I had to put if..then around that line to suppress the error, may be
some checks are needed for such broken fonts.

P.S. The font is freely available as adobe reader font pack
http://www.adobe.com/products/acrobat/acrrasianfontpack.html

Regards,
 Khaled


-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer

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%\definefontfeature[arabic][arabic][kern=no]
\font\arab=AdobeArabic-Regular*arabic\arab
\starttext 
\completecontent
\chapter{اختبار}
\stoptext

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Re: Bug with "Adobe Arabic" font kerning

[Hans Hagen]

Khaled Hosny wrote:
> The font seems to have a buggy (too big) GPOS kerning table (it does cause
> fontforge to hang writing the font). If 'kern' is set to 'yes', I get this
> error:
> 
> ...text/tex/texmf-context/tex/context/base/node-inj.lua:62:
> attempt to index local 'kb' (a nil value)
> 
> I had to put if..then around that line to suppress the error, may be
> some checks are needed for such broken fonts.

i don't get that error (might be catched already in my version) but 
indeed the font has weird kerning

(maybe the font is not really meant for using but just for rendering in 
the reader)

Hans

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

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Re: Bug with "Adobe Arabic" font kerning

[Khaled Hosny]

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On Sun, Apr 05, 2009 at 11:24:36PM +0200, Hans Hagen wrote:
> Khaled Hosny wrote:
>> The font seems to have a buggy (too big) GPOS kerning table (it does cause
>> fontforge to hang writing the font). If 'kern' is set to 'yes', I get this
>> error:
>>
>> ...text/tex/texmf-context/tex/context/base/node-inj.lua:62:
>> attempt to index local 'kb' (a nil value)
>>
>> I had to put if..then around that line to suppress the error, may be
>> some checks are needed for such broken fonts.
>
> i don't get that error (might be catched already in my version) but  
> indeed the font has weird kerning

OK, I'll try to re-test with the next beta.

>
> (maybe the font is not really meant for using but just for rendering in  
> the reader)

They offer it for sale as well[1], but it might not be the exact font
files.

[1]http://store1.adobe.com/cfusion/store/html/index.cfm?store=OLS-US&event=displayFontPackage&code=1741

Regards,
 Khaled


-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer

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___________________________________________________________________________________
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
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___________________________________________________________________________________

Re: Bug with "Adobe Arabic" font kerning

[Idris Samawi Hamid ادريس سماوي حامد]

On Sun, 05 Apr 2009 15:24:36 -0600, Hans Hagen <pragma@wxs.nl> wrote:

> Khaled Hosny wrote:
>> The font seems to have a buggy (too big) GPOS kerning table (it does  
>> cause
>> fontforge to hang writing the font). If 'kern' is set to 'yes', I get  
>> this
>> error:
>>  ...text/tex/texmf-context/tex/context/base/node-inj.lua:62:
>> attempt to index local 'kb' (a nil value)
>>  I had to put if..then around that line to suppress the error, may be
>> some checks are needed for such broken fonts.
>
> i don't get that error (might be catched already in my version) but  
> indeed the font has weird kerning

The VOLT sources for Adobe Arabic are freely available:

http://blogs.adobe.com/typblography/2007/06/adobe_arabic_sa.html

Looking at the kerning, it appears at first glance to be contextual single  
adjustment kerning that's messing things up. Will make some test files  
this week <sigh>. Basically, Single Adjustment uses the advance width  
parameter alone, with dx/dy=0. This should move the right sidebearing of  
an initial arabic char to the right while leaving the left one alone. In  
pair adjustment Arabic kerning generally sets dx=c=width. mkiv supports  
the latter but not the former. I'll continue this discussion with Hans off  
list. It's a weird font -- all due respect to Tim Halloway the designer  
*** -- but very complete in many ways. A good test case for mkiv.

Best wishes
Idris

*** Arabic Palatino by Zapf looks really weird too.

-- 
Professor Idris Samawi Hamid, Editor-in-Chief
International Journal of Shi`i Studies
Department of Philosophy
Colorado State University
Fort Collins, CO 80523
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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