The font doesn’t change; the RTL-enabled font contains mirrored glyph variants for characters that don’t have mirrored character counterparts. Cambria Math contains a myriad glyph variants for various purposes, such as scripts, scriptscripts, multiple sizes of brackets, etc. Mirrored glyph variants are just another case where glyph variants solve a problem. I wrote a blog post<http://blogs.msdn.com/b/murrays/archive/2010/01/12/special-capabilities-of-a-math-font.aspx> that attempts to explain these things.
Murray
From: neil.soiffer@gmail.com [mailto:neil.soiffer@gmail.com] On Behalf Of Neil Soiffer
Sent: Wednesday, February 20, 2013 11:37 AM
To: Murray Sargent
Cc: Paul Topping; Khaled Hosny; Kent Karlsson; David Carlisle; Daniel Marques; www-math@w3.org
Subject: Re: Mirroring Unicode symbols in Arabian
Murray,
Is what you are saying that this OpenType type feature "magically" switches the font it uses (internally). Lacking that, one needs to manually switch the font that is used for mirrored characters just as one would switch to a sans serif font is that is what is wanted. Is that your point?
Neil
On Wed, Feb 20, 2013 at 11:24 AM, Murray Sargent <murrays@exchange.microsoft.com<mailto:murrays@exchange.microsoft.com>> wrote:
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)?"