From: Philippe Verdy (verdy_p@wanadoo.fr)
Date: Tue Aug 28 2007 - 01:10:34 CDT
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
boxes.
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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