Re: Arabic letters separated by markup

From: John Hudson (
Date: Fri Jun 10 2005 - 20:17:41 CDT

  • Next message: Jony Rosenne: "RE: Arabic letters separated by markup"

    Kent Karlsson wrote:

    > That does not really follow. I think "inline" tags *between*
    > Arabic/Syriac/
    > Mongolian letters (possibly with combining marks) can be seen as acting
    > like
    > ZERO-WIDTH JOINER for the purpose of Arabic/Syriac/Mongolian shaping.
    > Certain changes that the markup may result in, such as a size change,
    > will
    > make the join more or less "misfit" graphically. But whoever wrote the
    > markup
    > asked for a size change, not a joining change. Ligature formation should
    > (always) be blocked over markup tags.

    But if one letter is at 20pt and another is at 12pt, how can the form a ligature? or if
    one is bold and the other is italic? This is the sort of stylistic change that might be
    affected by inline markup. The kind of glyph processing lookups that control e.g. basic
    Arabic shaping, ligation, etc. are all font-specific. As soon as you change the font, you
    are dealing with completely separate runs of glyphs that will be independently shaped.

    It is just about possible to imagine that something like basic Arabic shaping *could* be
    maintained, in that the character level analysis performed an engine might recognise that
    one Arabic character is being followed by another Arabic character, so would not apply
    final form shaping. But it seems much more likely that the glyph run boundary will
    interpreted as a text boundary for shaping purposes. With ligatures, I don't see how it is
    possible at all to maintain shaping across run boundaries, since the ligature is a single
    glyph in a single font.

    John Hudson

    Tiro Typeworks
    Vancouver, BC
    Currently reading:
    Truth and tolerance, by Benedict XVI, Cardinal Ratzinger as was
    War (revised edition), by Gwynne Dyer

    This archive was generated by hypermail 2.1.5 : Fri Jun 10 2005 - 20:19:09 CDT