Re: Combining across markup? (Was: RE: sign for anti-neutrino - gree k nu with diacritical line aboveworkaround ?)

From: Peter Kirk (peterkirk@qaya.org)
Date: Mon Aug 09 2004 - 15:11:20 CDT

  • Next message: Mike Ayers: "RE: Combining across markup? (Was: RE: sign for anti-neutrino - g ree k nu with diacritical line aboveworkaround ?)"

    On 09/08/2004 18:30, Mike Ayers wrote:

    > ...
    >
    > > Mozilla, and lots of other software can't handle mixing
    > > markup and combining marks or characters.
    >
    > Hmmm... Don't want to start a war, but I do have to ask.
    >
    > Isn't this correct behavior? Doesn't the code above
    > explicitly separate the two codepoints to prevent them from being
    > rendered as a sequence? I mean, if I wanted to display nu, then
    > macron, without combining behavior, wouldn't this be one way to do it? ...
    >

    This is an interesting one in the light of discussions elsewhere on
    Hebrew Holam. If you really want nu followed by a non-combining macron,
    Unicode has defined ways of doing this. Inserting ZWNJ is *not* one of
    them, and I wouldn't expect any kind of break or control character to
    have this effect by default. The correct way to do this is probably to
    insert SPACE or NBSP, or the proposed INVISIBLE CHARACTER. And then of
    course there is the spacing clone of the macron, U+00AF.

    But then this makes me realise that the problem someone has recognised
    with ZWNJ and combining characters in MS Word may be because ZWNJ is
    somehow interpreted as in a different font or otherwise having separate
    markup, perhaps because there is no ZWNJ glyph in the seleted font.

    > ... Combining across markup seems counterintuitive (and a violation
    > of layering) to me.
    >
    >
    I wouldn't consider this a violation of layering. If layer A has to
    split a string at a particular place because of its own functions, that
    does not imply a break at layer B. And it is certainly a legitimate user
    requirement for a combining mark to be in a different colour from its
    base character. What is the best way to represent that is debatable, but
    some kind of markup at this point should not be ruled out in principle.

    In any case markup cannot be allowed to break all intelligent font
    features. Should kerning be broken because a particular letter is in a
    different colour or underlined? 

    -- 
Peter Kirk
peter@qaya.org (personal)
peterkirk@qaya.org (work)
http://www.qaya.org/

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