Re: It is easy to predict the past.

From: Gregg Reynolds (unicode@arabink.com)
Date: Tue Jun 14 2005 - 19:45:51 CDT

  • Next message: Gregg Reynolds: "Re: Arabic letters separated by markup"

    John Hudson wrote:
    > Gregg Reynolds wrote:
    >
    >> Nah. The question is which "ligatures" (I prefer "compound forms") are
    >> required by Generally Accepted Principles of Arabic Writing. That would
    >> be the lam-alif only; I don't see how one could get rid of it.
    >
    >
    > Again, you need to be clear whether you are talking about a ligature in
    > a strict technical sense, i.e. a single glyph representing more than one
    > character, or in a looser sense of two letters that are written together
    > in a special form. As I explained in my earlier message, demonstrated
    > with VOLT lookup syntax, it is perfectly possible to render the lam_alif
    > 'ligature' without using a ligature glyph. It will still look like the
    > traditional and obligatory typeform, but it will not be a single glyph:
    > it will be two special glyphs, contextually substituted and linked using
    > either a cursive attachment anchor or simple kerning.
    >
    > This is what I mean when I say that Arabic can be typeset without using
    > ligatures: I'm not talking about styles of disconnected Arabic, or
    > Arabic without the obligatory lam_alif shaping. I'm talking about
    > typesetting technologies for Arabic in which multiple characters are
    > never rendered using a single glyph. I am using the term ligature in
    > this strict technical sense.

    Doh! I knew that. Really. Sorry. You're absolutely correct that
    things can be done that way. In fact, if you take a look at the
    metafont sources for ArabTex, which has been widely used in the
    (Western) Arabic publishing world for years, you'll see the author
    composes basic letter forms out of little chunks of ink. E.g., (if
    memory serves) the "tooth" letters like ba, ta, etc. are composed out of
    an initial tooth glyph, a medial glyph, and a final tooth, plus the dots.

    But on the other hand, I think this argues for a change in terminology.
      Everybody says "ligature"; but if you really want people to know what
    you're talking about you have to qualify it endlessly.

    -g

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