Re: DIY OpenType Re-ordering

From: Philippe Verdy (verdy_p@wanadoo.fr)
Date: Fri Mar 24 2006 - 09:23:38 CST

  • Next message: Philippe Verdy: "Re: DIY OpenType Re-ordering"

    919, 94D : dead "NG" (NGA + VIRAMA): uses full NGA with subjoined halant by default, or half-form NGA if followed by consonnant, or half-form NGA, unless ligatured with next consonnant.
    915, 93F : live "KI" (KA + I): uses full-KA form, unless ligatured with previous consonnant.

    The choice between full-form NGA with subjoined halant or half-form depends on locale, but by default NGA and KA do not ligate, and traditionnaly NGA has no half-form (or its half-form is identical to its full form so the halant must be shown) because it does not have a danda on the right.

    The vowel I (appearing on right) is reordered before consonnants of the cluster, so we get this rendering:

    Vowel I, NGA with subjoined HALANT, full-form KA, and possibly the two consonnants in a ligature if applicable to the locale.

    This is fully described in Unicode...

    If you insert a ZWJ in the middle you prohibit the possible ligature of NGA and full-form KA, but you force the half-form of NGA if the font has one. Anyway, the vowel I is still reordered before the half-form NGA. There's no dictinction here in Hindi because there's no ligature conjunct for "NG.KA".

    If you insert a ZWNJ, it blocks the reordering of I before dead NGA, but NGA keeps its half-form if ever it has one in the locale (not with the Mangal font for Hindi). You should get:

    NGA with subjoined HALANT, Vowel I, full-form KA.

    This is an alternate orthography, but you'll still read it the same : "NG.K.I"...

    Philippe.

    ----- Original Message -----
    From: "Antoine Leca" <Antoine10646@leca-marti.org>
    To: <unicode@unicode.org>
    Sent: Friday, March 24, 2006 1:25 PM
    Subject: Re: DIY OpenType Re-ordering

    > Kent Karlsson wrote:
    >> The short-i matra (if fully implemented) glyph should be
    >> displayed to the left of the display of *any* combining
    >> sequence it is applied to.
    >
    > I am not sure this rule is full correct: is <U+0919, U+094D, U+0915, U+093F>
    > one, or two, combining [character] sequences? Where is it spelled out? What
    > if ZWJ or ZWNJ are inserted in the middle?
    >
    > At any rate it is not prescribed by Unicode, it is a rendering issue.



    This archive was generated by hypermail 2.1.5 : Fri Mar 24 2006 - 09:35:19 CST