RE: help regarding UNICODE

From: Apurva Joshi (apurvaj@microsoft.com)
Date: Mon Sep 18 2000 - 13:00:46 EDT


Hello Paresh Agarwal,

Below are brief responses to your questions. They pertain to making Indic
fonts based on Unicode, using TrueType outlines, for Windows.

Q1. What is the difference between Unicode fonts and other fonts?
A:
The cmap table for Unicode fonts for Indic scripts on Windows, will have a
subtable for: platform ID 3, encoding ID 1, format 4.

The font would need to contain a glyph each which is mapped to corresponding
codepoints from the Indic script that it is being planned for. eg. a font
for Gujarati needs to have a glyph each for allocated codepoints in the
range: U+0A80 - U+0AFF.
In addition to these, the font might have:
a). glyphs for conjuncts and
b). variants for vowel signs (matras), vowel modifiers (Chandrabindu,
Anuswar); consonant modifier (Nukta) for typographic requirements.
c). digits and punctuation marks from any other range that you might want to
add (perhaps some that you think appropriate from the Latin ranges?)

The contents of (a) and (b) depends not only on the typographical quality
that you would like the font to acheive but also whether the font is meant
for supporting contemporary character contents of the script or a more
traditional one.

The contents of (a) and (b) can be accessed by providing a Glyph
Substitution table in the font. Such a table is more often than not a
necessity for Indic scripts. A Glyph Positioning table is also a need--
atleast for achieving the minimal required mark positioning in such scripts.
More information on these, perhaps you might want to see sections devoted
them, beginning at: http://www.microsoft.com/typography/tt/tt.htm

A specification for "Creating and Supporting OpenType fonts for Indic
scripts" is available at:
http://www.microsoft.com/typography/otspec/indicot/default.htm .

Q2. Are there separate Unicode fonts?
A:
A font that has glyphs mapped as above is a Unicode font. Although some
tables for such fonts are common and a necessity (cmap, name, OS/2 etc.);
others will depend on the type of glyph outlines (TrueType, PostScript...)

Q3: If yes, where are they available?
A.
MS has made two OpenType Indic script fonts with TrueType outlines;
available with Windows 2000. They are Mangal.ttf (for Hindi) and Latha.ttf
(for Tamil). Mangal is also available for download from the community site
of VOLT (more on this below).

Q4: Is it possible to convert other fonts to Unicode?
A.
Yes, please refer the specs mentioned above.
In addition, the Visual OpenType Layout Tool has been made available to an
active online community for a while. A version 1.00 has recently been
released. This tool provides a user friendly interface for adding layout
tables to fonts. More information at:
http://www.microsoft.com/typography/developers/volt/default.htm . In
addition a sample Indic font for Hindi can also be downloaded from the
community.

Q5: Is keyboard arrangement in Unicode system different form that of the
regular ttf fonts??
A.
Keyboards provided with Windows 2000 for Indic scripts have referred to
ISCII keyboard layouts-- INSCRIPT. These can been seen at:
http://www.microsoft.com/globaldev/keyboards/keyboards.asp .

Thanks,
-apurva

-----Original Message-----
From: mlinguist [mailto:mlinguist@mantraonline.com]
Sent: Wednesday, September 13, 2000 7:44 PM
To: Unicode List
Subject: help regarding UNICODE

I am enthusiastic to know about Unicode font system in depth, specifically
with regard to Indian languages. Would anyone suggest how to go about all
this?
What is the difference between Unicode fonts and other fonts? Are there
separate Unicode fonts? If yes, where are they available? Is it possible to
convert other fonts to Unicode?
Is keyboard arrangement in Unicode system different form that of the regular
ttf fonts?? etc.....
I would be greatful for any help in this regard.
Best regards
Paresh Agarwal
Multi-Linguist- Translation agency
mlinguist@mantraonline.com

 



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