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Re: Mirroring Unicode symbols in Arabian

From: Tom Leathrum <leathrum@jsu.edu>
Date: Wed, 20 Feb 2013 14:10:18 -0600 (CST)
To: Paul Topping <pault@dessci.com>
Cc: Neil Soiffer <neils@dessci.com>, Kent Karlsson <kent.karlsson14@telia.com>, David Carlisle <davidc@nag.co.uk>, Daniel Marques <dani@wiris.com>, www-math@w3.org, Murray Sargent <murrays@exchange.microsoft.com>, Khaled Hosny <khaledhosny@eglug.org>
Message-ID: <31242830.572.1361391039198.JavaMail.moth@bluejay>
If I may interject here:

Paul, I think Murray's point about semantics addresses your concern, because if there is a semantic difference between reversed symbols in LTR then they will be represented in different Unicode values.  Consider for example U+2282 "subset" and U+2283 "superset" -- the glyphs are mirror-images, and both are marked as mirror="Y" for RTL.  RTL would have the visual effect of swapping these two glyphs, but in fact their Unicode values wouldn't change because the semantics would still be the same -- U+2282 would be semantically "subset" whether it is mirrored or not, and in RTL the glyph for it would look (to LTR readers) like a superset symbol.  Clear as mud?


----- Original Message -----
From: "Paul Topping" <pault@dessci.com>
To: "Murray Sargent" <murrays@exchange.microsoft.com>, "Khaled Hosny" <khaledhosny@eglug.org>
Cc: "Neil Soiffer" <neils@dessci.com>, "Kent Karlsson" <kent.karlsson14@telia.com>, "David Carlisle" <davidc@nag.co.uk>, "Daniel Marques" <dani@wiris.com>, www-math@w3.org
Sent: Wednesday, February 20, 2013 1:46:15 PM
Subject: RE: Mirroring Unicode symbols in Arabian

So this means that reversing a symbol to express a mathematical concept is unavailable to non-RTL text even though the fonts and the font rendering mechanism has the capability.

Paul

> -----Original Message-----
> From: Murray Sargent [mailto:murrays@exchange.microsoft.com]
> Sent: Wednesday, February 20, 2013 11:36 AM
> To: Paul Topping; Khaled Hosny
> Cc: Neil Soiffer; Kent Karlsson; David Carlisle; Daniel Marques; www-
> math@w3.org
> Subject: RE: Mirroring Unicode symbols in Arabian
> 
> I meant that the codes for the mirrored integral, etc., are exactly the
> same as the unmirrored symbols. The display software just mirrors them
> in RTL math zones. If you use OpenType, you used the 'rtlm' feature or
> shaping, as the characters warrant. This is the same thing as for
> mirrored characters that have mirrored character counterparts. An open
> paren is U+0028 whether it's mirrored or not.
> 
> Murray
> 
> -----Original Message-----
> From: Paul Topping [mailto:pault@dessci.com]
> Sent: Wednesday, February 20, 2013 11:31 AM
> To: Murray Sargent; Khaled Hosny
> Cc: Neil Soiffer; Kent Karlsson; David Carlisle; Daniel Marques; www-
> math@w3.org
> Subject: RE: Mirroring Unicode symbols in Arabian
> 
> Not sure how this answers my question.
> 
> Paul
> 
> > -----Original Message-----
> > From: Murray Sargent [mailto:murrays@exchange.microsoft.com]
> > Sent: Wednesday, February 20, 2013 11:24 AM
> > To: Paul Topping; Khaled Hosny
> > Cc: Neil Soiffer; Kent Karlsson; David Carlisle; Daniel Marques; www-
> > math@w3.org
> > Subject: RE: Mirroring Unicode symbols in Arabian
> >
> > Mirrored glyphs are a display feature, not a semantic one.
> >
> > Murray
> >
> > Paul Topping asked, "If access to these characters requires use of
> > this OpenType feature, does it imply that such characters will not be
> > accessible from applications that simply process Unicode text strings
> > (eg, web browsers and most other apps)?"
Received on Wednesday, 20 February 2013 20:10:47 GMT

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