W3C home > Mailing lists > Public > w3c-wai-ig@w3.org > July to September 2001

Re: oops, equations, meant to send to all of WA IG

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 30 Jul 2001 08:54:16 -0400 (EDT)
cc: <w3c-wai-ig@w3.org>
Message-ID: <Pine.LNX.4.30.0107300848490.20378-100000@tux.w3.org>
Hmm. If the equation is marked up


(You need the punctuation to get all the markup) then it might account for
the 2 being reduced to the baseline. (Something about the difference between
presentation and semantics springs to mind here).

I believe that MathML and LateX are supposed to be transformable from one to
the other. Anybody tried it?


On Mon, 30 Jul 2001, Steven McCaffrey wrote:

  Oops, I meant to send my comments regarding
  equations to all of WAI IG and just realized I only sent them to Dave.

  Here is what I sent.

  Yes, I agree.  MATHML is not yet supported by screen readers.
  Personally, I prefer simple ASCII (or even LaTex source) representations because there is less chance of ambiguity than there might be with words.
  If ASCII is used, be careful of multiline fractions where dashes are used to represent the line separating numerator from denominator.  Since a screen reader reads one line at a time, the user will hear just the numerators then the next line the user will hear something like dash dash dash then the next line will be the sequence of denominators.  As you might imagine, this is very confusing.
  It's better to do something like
  [(x+2)/3] + [(x+4)/5] = 8.
       I have come across many sites that seem to be using ASCII but for some reason the exponent comes out on the base line.  Many sites have Einstein's famous equation expressing the equivalence of mass and energy as (what sounds like)
  e = mc2.  Since I know what the equation is supposed to be, using the up arrow for exponentiation, it should be
  e = mc^2, (happily, some sites have this representation).  Does anyone know why, on some sites, the exponent comes out on the baseline?

  >>> <D.W.Russo@sas.com> 07/30/01 06:34AM >>>

  I am not an expert, but I have been researching this issue a bit.

  For an overview of ways to make equations accessible, see these guidelines from the CPB/WGBH National Center for Accessible Media:


  In regard to MathML, today's browsers and accessibility software do not seem to provide significant MathML support. See the thread in this list: "MathML and screen readers"

  My general impression is that if your documents contain relatively few, simple equations, you might be able to do something that will give at least some visually-impaired people access to your equations. If you have a large library of documents with complex equations, the challenge is much greater.



Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409 134 136
W3C Web Accessibility Initiative     http://www.w3.org/WAI    fax: +1 617 258 5999
Location: 21 Mitchell street FOOTSCRAY Vic 3011, Australia
(or W3C INRIA, Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, France)
Received on Monday, 30 July 2001 08:54:17 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 13 October 2015 16:21:13 UTC