Re: visible glyphs for U+2062 and similar characters

From: Mark Davis (mark.davis@jtcsv.com)
Date: Tue May 13 2003 - 10:59:21 EDT

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    The default mappings in the font for all Default Ignorable Code Points
    should be to a zero-width invisible glyph: that is the expected
    appearance when printing and in a WYSIWYG editor.

    I agree that it would be good to have alternate, visible glyphs
    available for a "Show Hidden" mode, but these glyphs don't actually
    have to be duplicated in each font; the editing code can use a special
    font when that mode is turned on.

    Märk Davis
    ________
    mark.davis@jtcsv.com
    IBM, MS 50-2/B11, 5600 Cottle Rd, SJ CA 95193
    (408) 256-3148
    fax: (408) 256-0799

    ----- Original Message -----
    From: "Andrew C. West" <andrewcwest@alumni.princeton.edu>
    To: <unicode@unicode.org>
    Cc: <jameskass@att.net>
    Sent: Tuesday, May 13, 2003 04:49
    Subject: Re: visible glyphs for U+2062 and similar characters

    > On Mon, 12 May 2003 20:44:14 +0000, jameskass@att.net wrote:
    >
    > > Visible glyphs for control characters can be useful in plain text
    > > editing/input and for filling out Unicode charts. But, if this is
    > > messing things up for other applications, those glyphs could be
    > > removed from Code2000.
    >
    > I think that it is a good idea for fonts to provide visible glyphs
    for invisible
    > characters (as do many fonts, not only Code2000), and it should be
    up to the
    > rendering engine to not display an invisible character where it is
    inappropriate
    > to be displayed visibly.
    >
    > For example, Code2000 provides visible glyphs for U+180B through
    U+180D
    > [MONGOLIAN FREE VARIATION SELECTOR ONE ... THREE]. With the latest
    version of
    > Uniscribe the visible glyphs for FVS1..3 are displayed when the
    characters are
    > in isolation or set within non-Mongolian text, but when the
    characters are set
    > within Mongolian text Uniscribe does not render FVS1..3 at all (i.e.
    they are
    > invisible). This behaviour is extremely useful :
    >
    > 1) It allows invisible characters to be invisible when set in the
    appropriate
    > context (e.g. within running Mongolian text for FVS1..3)
    >
    > 2) It allows visible representation of invisible characters in
    Character Map
    > applications, etc.
    >
    > 3) It allows visible representations of invisible glyphs in
    metalanguage
    > contexts.
    >
    > 4) It allows the user to easily notice cases where an invisible
    character has
    > been inadvertently placed or left in an inappropriate textual
    context.
    >
    > Similar behaviour could be implemented for U+2062 [INVISIBLE TIMES]
    and other
    > invisible characters by the rendering engine (e.g. do not render
    U+2062 between
    > numbers, elsewhere render the visible glyph).
    >
    > In short, visible glyphs for invisible characters are indeed useful
    in some
    > contexts, and I would be sorry to see them disappear from Code2000.
    >
    > Regards,
    >
    > Andrew
    >
    >

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