From: John Hudson (firstname.lastname@example.org)
Date: Sat Jun 16 2007 - 19:49:08 CDT
Samuel Thibault wrote:
> Ok, but my question is: should it have an entry for U+200D, or should
> the font engine know that U+200D doesn't render anything and thus not
> having an entry for it is fine (and avoids displaying .notdef)?
Ah. At least from Microsoft's perspective, the font should contain glyphs for U+200D and
other control characters even though these glyphs will not be displayed most of the time.
For editing purposes, it can be useful to turn on display of such control characters, and
programs like MS Word allow this in the options setting. So fonts should actually contain
zero-width but visible and distinguishable glyphs for these control characters, even
though the display of these glyphs is suppressed unless the user turns them on.
The suppression of control character glyph display is something that happens after font
layout processing, in case the glyphs are used in glyph substitution lookups as sometimes
happens. This means they are actively suppressed and not simply ignored for display
purposes. So the moment at which the application determines that the font is missing a
cmap entry for the control character occurs long before a decision about whether to
display the glyph.
-- Tiro Typeworks www.tiro.com Gulf Islands, BC email@example.com We say our understanding measures how things are, and likewise our perception, since that is how we find our way around, but in fact these do not measure. They are measured. -- Aristotle, Metaphysics
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