From: James Kass (firstname.lastname@example.org)
Date: Wed Jul 18 2007 - 00:25:12 CDT
> 1) There is absolutely no requrement, from Unicode's side, to include a dotted
> circle in a font.
> 2) As I've mentioned (quite often by now), Unicode does NOT require inserting
> dotted circles like that.
Indeed. On some sytems, though, if a font does not include
a glyph for the dotted circle character, the combining mark
will be displayed on the "missing glyph" instead.
Quoting from the Microsoft OpenType Indic specifications at:
“For the fallback mechanism to work properly, an Indic OTL
font should contain a glyph for the dotted circle (U+25CC).”
(Note that the page appears to have been around since 2001.)
Sinnathurai Srivas' observation about Indic fonts generally
including a glyph for the dotted circle character is true
because programmers tend to build OpenType Indic software
according to the Indic OpenType specifications.
> However, it does not rule it out either, as it should do (at some appropriate level).
> (There is no dotted circle in the character string below, but some systems, ill-advicedly,
> insert one
> during display.)
(Well, some system between us apparently inserted line feed characters
into your *text*.)
To forbid an operating system from inserting some kind of a
control picture in the display to highlight that which is “invalid”
would be just about as bad as forbidding an operating system from
inserting a line-feed (character) into the *display* where needed. (Of course, line-wrap can usually be turned off by people who like scrolling sideways.)
The trick is to make sure that the font-engine handles all
reasonable user expectations as “valid” ones. There's a learning
curve involved, as there is with most nascent endeavors.
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