bugFree UCS Outline Fonts - Bugs: bug #22329, Arabic not really working

 
 

bug #22329: Arabic not really working

Submitted by:  Steve White <Stevan_White>
Submitted on:  Sat 16 Feb 2008 09:21:36 AM UTC  
 
Category: character rangeSeverity: 5 - Blocker
Item Group: glyph(s) incorrectStatus: Fixed
Privacy: PublicAssigned to: Steve White <Stevan_White>
Open/Closed: ClosedRelease: 2006-01-26

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Fri 12 Sep 2008 08:23:50 AM UTC, comment #5:

In release 20080912

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sat 01 Mar 2008 10:25:38 AM UTC, comment #4:

In CVS

Arabic now seems to be working, in a limited way, for display of modern text.

Tested agains sample page
http://people.w3.org/rishida/scripts/samples/arabic.html
(text attached).

  • Drew several glyphs for special forms of yeh
  • Drew sukun combining diacritical
  • Made some diacritical combining marks to be properly zero width.
  • Added 'init' 'medi' 'fina' tables to convert letters to

their initial, medial, and final forms within words.
(modified script attached)

  • Added 'rlig' table for required ligatures of lam and alif
  • Constructed the lam-alif ligatures.

Not done:
* may be more required ligatures of lam and alif
* other common ligatures
* 'mark' table for better positioning of diacriticals
* 'mark' table for positioning vowels
* 'locl' table for localized forms of certain letters
* 'ccmp' table for decomposing ligatures

(file #15148, file #15149)

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Fri 29 Feb 2008 08:22:40 PM UTC, comment #3:

In CVS,

moved entire ranges down by 200 EM
Arabic
Arabic Presetation Forms
lots more to do.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sat 16 Feb 2008 11:51:05 PM UTC, comment #2:

Here is the script I mentioned. It will need more work.

First create the proper empty tables as described in the script.

Then
$ fontforge -script arabic_replacements.pe FreeSerif.sfd

(file #15053)

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sat 16 Feb 2008 11:01:32 PM UTC, comment #1:

The FreeSerif glyphs were added inn 2003 by Primoz. He wrote in CVS: "A rather naive composition of Arabic "accented" charachers, based on the work of Abbas Izad."

Well, the glyphs really are pretty, and ought to be saved.

The init, medi, and fina lookups are missing, to do the necessary replacements of initial, medial, and terminal forms for Arabic.
The Wikipedia page http://en.wikipedia.org/wiki/Arabic_alphabet
lists most of the required changes.

But adding such extensive tables to a font is very hard and tedious work, prone to mistakes. Using http://fontforge.sourceforge.net/scripting.html,
I have now written a crude script that allows me to conveniently add lookup tables to a font.

The only thing missing is an issue that at least involves "yat" vs "'alif maqṣūr" mentioned in the link. Some replacement glyphs seem to be missing. Expert advice on Arabic is needed for these.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Sat 16 Feb 2008 09:21:36 AM UTC, original submission:

It appears that Arabic in FreeSans is broken as to be useless for display of Arabic text.
The necessary replacements of initial-medial-final forms are not performed.

I tried it in oowriter and gedit.
This page shows a picture of some text with the Unicode, for those of us who can't read Arabic:
http://people.w3.org/rishida/scripts/samples/arabic.html

I thought we might have broken it somehow with the recent commits, so I got a previous version out of CVS, built and installed it. Same problem.

How long has this been broken? Did Arabic ever work in FreeSerif?

Comparing its replacement tables with other fonts that do support Arabic, well, they're quite different. But in FreeSerif, I see a lookup
'rlig' Required Ligatures in Arabic lookup 1
'liga' Standard Ligatures in Arabic lookup 7
But the first only has 2 entries, and the second only 1!
By contrast, the ArabEyes Arab font has 4 tables, 'init' 'medi' 'fina' and 'liga', each with many entries.

Where are the replacement tables for Arabic in FreeSerif?

FreeSerif advertizes the Arabic character range. This should be turned off until this issue is resolved.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):
   
   
Comment:
   

Attached Files
file #15148:  arabic_sample.txt added by Stevan_White (776B - text/plain - sample arabic text, revised replacements script)
file #15149:  arabic_replacements.pe added by Stevan_White (4KiB - application/octet-stream - sample arabic text, revised replacements script)
file #15053:  arabic_replacements.pe added by Stevan_White (3KiB - application/octet-stream - arabic_replacements.pe)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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    Follow 7 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Fri 12 Sep 2008 08:23:50 AM UTCStevan_WhiteStatusFix posted=>Fixed
      Open/ClosedOpen=>Closed
    Sat 01 Mar 2008 10:25:38 AM UTCStevan_WhiteAttached File-=>Added arabic_sample.txt, #15148
      Attached File-=>Added arabic_replacements.pe, #15149
      StatusProceeding=>Fix posted
    Fri 29 Feb 2008 08:22:40 PM UTCStevan_WhiteStatusConfirmed=>Proceeding
    Sat 16 Feb 2008 11:51:05 PM UTCStevan_WhiteAttached File-=>Added arabic_replacements.pe, #15053

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