Re: Proposing two new Arabic ligature characters

From: John Hudson (tiro@tiro.com)
Date: Mon Nov 18 2002 - 15:46:01 EST

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    At 12:18 11/18/2002, Karwan Salih wrote:

    >I'm about to propose two new Arabic ligature characters formed by Arabic
    >letter LAM with small V above (uni0685) followed by Arabic letter ALEF
    >(uni627), both in isolated and final forms. Those characters are used by
    >Kurdish language speakers. The
    ><http://www.kurdstan.com/Arabic.pdf>www.kurdstan.com/Arabic.pdf PDF files
    >explains four examples of already coded Arabic ligature characters and the
    >proposed new characters. I'm new to the Unicode world and your suggestions
    >will be appreciated.

    Please note that ligatures do not need to be encoded. Arabic script
    ligature formation is best handled at the glyph level, using layout engines
    and smart font formats with glyph substitution lookups. I'm familiar with
    the Kurdish ligatures to which you refer, and have successfully implemented
    these in fonts without needing to encode the ligatures.

    For an example of layout engine and smart font combination, as implemented
    on Windows, see

    http://www.microsoft.com/typography/developers/opentype/default.htm

    For sepcific information about the Windows Arabic script engine, see

    http://www.microsoft.com/typography/otfntdev/arabicot/default.htm

    The existing Arabic ligatures in the Unicode Standard are present only for
    compatibility with a pre-existing character set. Their use is not
    recommended and the Unicode Technical Committee will not add new ligatures
    because this would break existing normalisation (composition/decomposition)
    implementations.

    John Hudson

    Tiro Typeworks www.tiro.com
    Vancouver, BC tiro@tiro.com

    It is necessary that by all means and cunning,
    the cursed owners of books should be persuaded
    to make them available to us, either by argument
    or by force. - Michael Apostolis, 1467



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