RE: Questions on ZWNBS - for line initial holam plus alef

From: Kenneth Whistler (
Date: Mon Aug 11 2003 - 15:57:11 EDT

  • Next message: Jim Allan: "Re: Questions on ZWNBS - for line initial holam plus alef"

    Kent asked:

    > How should a freestanding double diacritic be encoded (for purposes of
    > meta-discussions, and the like): <SPACE, dbl diacritic> or <SPACE, dbl
    > diacritic, SPACE>?

    It *could* be represented as <SPACE, dbl_diacritic, SPACE>, of course,
    or for that matter <SPACE, dbl_diacritic, TAB>, or other possibilities.
    The combining character sequence, in either case, is the
    <SPACE, dbl_diacritic> sequence.

    But it *should* be represented by something visually more
    meaningful, such as <U+25CC, dbl_diacritic, U+25CC>, which is
    how the standard itself tends to represent it when needing
    to engage in a meta-discussion. The whole point of a double
    diacritic is its graphic application to two base characters,
    which point is lost in the discussion if you don't show a
    graphic base when displaying the character in isolation.

    > How should combining characters (spacing as well
    > as non-spacing) that are not vertically centered *roughly* be displayed,
    > e.g. <SPACE, right-side combining character>, should that *roughly*
    > be displayed with or without a typographic void to the left of it?

    It's up to the application. And again, I would say that if this
    level of detail is a concern to the person originating the text,
    then the better convention is to represent the combining character
    on a *visible* generic base.

    > So
    > if I want a space (though not an overgrown one), should one use
    > <SPACE, SPACE, right-side combining character>? Or even <SPACE,
    > ZWSP, SPACE, right-side combining character>, to prevent "space
    > collapse".
    > And similarly for left-side combining characters. Likewise for defective
    > combining sequences. If I want a visible pseudo-base, a dotted ring, or
    > an
    > underline, the answers are fairly clear, using a suitable character as a
    > base.

    Exactly. Which is why you should use such conventions if you
    care about the placement in this detail.

    Otherwise, you up-level and make use of whatever mechanisms a
    typesetting application makes available for individual adjustment
    of the placement of glyphs.


    > But not for the cases above. I don't think that should entirely up
    > to each font (maker), without any recommendation. (A "should" rather
    > than a "shall" is quite sufficient.)
    > /kent k

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