RE: Control picture glyphs (was Re: Apostrophes at

From: Philippe Verdy (
Date: Tue Aug 28 2007 - 01:10:34 CDT

  • Next message: Philippe Verdy: "RE: Apostrophes at"

    Asmus Freytag wrote:
    > Variation selectors have no business being visible - unless you are in a
    > special mode. The whole idea behind them is that they can (and should)
    > be ignored when the resources to act on them (variant glyphs) are not
    > present.

    That's exactly the same conclusion I made when I suggested that renderers
    strip the variation selectors not supported in the selected font...

    There's never any good reason to show the .notdef glyph of that font,
    because according to Unicode reference, the sequence <char+VS> should be
    treated like <char> without the VS, (except in special algorithms described
    in the standard or its annexes) if the VS makes no sense with the available
    local data.

    If renderers were updated to do that, variation selectors could be used more
    easily and widely, and a reasonable default rendering would still be
    available if there's no font defining glyphs for the specific variations...
    and this would not create "bogous text" that readers are seeing, full of

    As variation selectors are to be used mostly by mathematicians (the
    direction of the stroke barring the equal sign in a "different" sign is most
    often not very important for reading, just needed for exact printing as
    intended by the author) or by Asian users (to make thez ideographs look like
    they prefer in their local culture, but they should have fonts designed for
    their culture, and if they are reading texts from another ideographic
    source, showing their own glyphs instead of the original ones could be
    solved by installing fonts supporting the VS sequences, if they can).

    But asking to them to support visible "squares" when they can't install such
    extended font is not a good way to progress. May be the fonts will come
    later, but this should not prohibit the production of texts using VS where
    needed, even if the exact variation glyphss can't still be displayed
    distinctly everywhere.

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