Re: 28th IUC paper - Tamil Unicode New

From: Richard Wordingham (richard.wordingham@ntlworld.com)
Date: Wed Aug 24 2005 - 02:52:59 CDT

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    (Retransmission and 'grammatical' update of message accidentally sent only
    to Antoine.)

    Antoine Leca wrote:

    > Then, it put the whole idea at the mercy of the correctness of the initial
    > analysis of the engine writers. For example, we had a discussion several
    > months ago about Devanagari, in the (rare) case where the resulting base
    > glyph of the conjunct does not contain all the consonants (the typical
    > example were TT.TTH.I ṭṭha <U+091F, U+094D, U+0920, U+093F> ट्ठि, when the
    > ट्ठ is lacking in the font): we find printings where the rendering looks
    > like ट्‌ठि, but were not able to find the other possibility (with the
    > i-matra at the extreme left), even if it is what is specified and
    > implemented in the OpenType rendering engines...

    Interesting. According to
    http://www.microsoft.com/typography/otfntdev/indicot/shaping.aspx , the
    problem has already been fixed for Malayalam:

    "Left Matras in Malayalam and Tamil

    In these languages the left (part of a) 'matra' is not placed in front of
    the whole syllable but immediately precedes the base glyph.

    The problem is that in presence of (font-dependent) consonant conjuncts it
    is impossible to predict to where the 'matra' should be reordered so that
    consonant conjunct ligatures don't have to "skip over" it.

    Although the Tamil script uses only one consonant conjunct (KSSA), conjuncts
    are in abundance in Malayalam.

    To solve the problem, Uniscribe always places the pre-base 'matras' at the
    beginning of the syllable for shaping. Then, for the above-mentioned scripts
    Uniscribe will reorder it before the base glyph at the end of script shape
    routine for correct placement. "

    I read a version of this dated December 2001 yesterday afternoon (Tuesday),
    but I
    couldn't find exactly the same web page last night.

    Richard.



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