Re: glyph choices for font encoding-version 1.2

["Dr.K. Kalyanasundaram" <kalyan@igcsun3.epfl.ch>]

Dear Nagu:
Thanks a lot for your prompt response/comments.
If you have not noticed, the current participants of the font encoding
scheme discussions also include those in the mailing list 
"tamilnet@tamilnews.org.sg" of the National Univ. of Singapore
and the members of the TNC.

Just a few quick responses to the points you raised:
i) The suggestions to include the copyright and registered mark signs
came from Mr. Leong Kok Yong of IRDU unit, NUS, Singapore.
Prof. Schiffman pointed out that if we add a few of these special
characters, it would avoid unnecessary changing the font back 
and forth.

ii) In addition to having the series ik, ing, ic, it,... I have
included  the 
"pulli" as a modifier glyph to go with the grantha characters.
In the present scheme all the uyirmeis of grantha characters are
generated using the modifiers. Such a scheme would be logical
and easy to remember during the learning process.

iii) As you know, early this year we debated a lot on whether or 
not kerning can be invoked to generate the "uyirmeis"
Many software developers such as Muthu, Ravi Paul repeatedly
expressed the desire to have as many uyirmeis as single glyphs
in the font encoding scheme to ensure high quality print out
required for prof. publishing houses. I chose to keep ik, ing,... series
as
such and invoke kerning only in the ikara and iikara varisai.
Right kerning often works out well as it involves back-tracking
a fixed number of pixels, irrespective of the size of the mei
character (on thin ones like ra as well as wider ones like Na).
Back-tracking "pulli" to go on top of mei does not work that
well. You need at least three or four back-tracking pullis to get
the pulli right at the center/top of the mei.  
My personal opinion is that such a combined approach would 
ensure optimization at the same time not loosing on aesthetics.
Of course there has to be some trade off, since there is no way
we can have all the 130+ unique tamil alphabets as such in any 
scheme.

iv)  In Mylai I use such a half-kall to get the thuu from thu etc.
As a right-end modifier such a half-kall should not pose any
problem in principle. So we can liberate a few more slots in this
way if necessary. I do not see any abs. necessity now.

v) character-encoding vs. font encoding - terminology
Unless you take for granted "interpreted output", in simple
fonts, there is a  one-to-one correspondance between the 
number of keystrokes used and the number of glyphs 
stored in the output text. When you go for "interpreted
output" using intelligent softwares, the output does not
even have to depend on the nature and quality of the
glyphs stored in the font. We should stick to "direct 
output" scenario and ensure that we can deliver decent
output of entire tamil alphabets.

vi) I kept talking about characters and glyphs because of
our desire to have the feasibility of storing the tamil text
generated using these simple 8-bit fonts in the unicode
format and vice versa.  In the last TamilNet'97 conference
at Singapore, there were several presentations where
tamil texts originating from tamil fonts are stored in 
unicode format. UC Berkeley Library is currently
looking into this possibility for cataloguing of all non-roman
language titles. So this is an important issue we have to
address. It is better we addres this now, if we are talking
about using the proposed 8-bit font concurrently with
evolving unicode schemes.

vii) Deciding on whether we go for 
7-bit font or 8-bit fonts, 
with or without diacritical markers,
with or without old style tamil alphabets, 
with or without grantha characters
is a difficult issue, since the choices are more at the
personal preferences level. 
Right now we are focussing on the technical aspects
of agreeing on what can go in a 8-bit polyvalent font.
Once we finish this and agree on an encoding scheme,
it will be a trivial issue to drop one or more of the
possibilities listed above. 
Even if Tamilnadu Committee goes for the scaled
down monolingual 7-bit font, it is not obvious whether
the tamil lovers around the world would agree.

You will find the following in the summary report of
discussion panel of the last TamilNet'97 Conference
held recently in Singapore:
"The panel agreed that there should be a unified 8-bit
character set that will co-exist with Unicode for the 
Tamil language. The TamilNadu Computer Standardization 
Committee will work with developers towards a unified 
8-bit character set. To facilitate the interchange of 
the myriad of 8-bit codes around, code conversion has 
to be provided for these codes. The use of Unicode as
the standard interchange code is proposed to coexist 
with the unified 8-bit character set for future..."

The present discussions are purely a follow up of the
above decision.

Kalyan