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RE: content guidelines checkpoint 3.1

From: Dave J Woolley <DJW@bts.co.uk>
Date: Tue, 8 Aug 2000 13:39:14 +0100
Message-ID: <81E4A2BC03CED111845100104B62AFB58248EE@stagecoach.bts.co.uk>
To: w3c-wai-ig@w3.org


> -----Original Message-----
> From:	Steven McCaffrey [SMTP:smccaffr@MAIL.NYSED.GOV]
> Sent:	Tuesday, August 08, 2000 12:59 PM
> To:	zacm@etr.org; w3c-wai-ig@w3.org
> Subject:	Re: content guidelines checkpoint 3.1
> 
> 
> 
>      Speaking only for myself, as one member of the WAI IG list, my
> interpretation is that no checkpoint is in any way equivalent to "don't do
> this" - just make sure that if you do do this, also provide ...
> "Alternative" does not mean "replace" but mostly "in addition to"
> Images of text cannot be read by screen readers for the blind, so some
> alternative must be provided in addition to, not in place of such images.
> 
I think this is only true at priority one, which makes a 
lot of concessions to market demands for a glossy appearance
on big two browsers for people with no vision defects.

As the priorities go up, the trend is towards only permitting
violations of the HTML philosophy when they are essential to 
the function of the application.

I'd therefore say that a priority 2 requirement that graphics of
text not be used is a real requirement for typical commercial
web pages, where they simply bulks out the contents, slow downloads,
and risk getting out of step with alternative text.

Even priority 1 is more than most commercial sites are prepared to go,
but priorities 2 and 3 must reflect a commitment towards accessibility
over glossy appearance.

I would have reservations on the MathML example, though, as most
people reading maths on the web will not have a MathML capable 
browser yet, e.g. the example at doc\amaya\Math.html#Links in the
Amaya 3.1 online documentation ( y = 1 / sqrt (x^2 + 1) ) comes 
out as "y = 1 x 2 + 1 " in IE 5.1 (there may be accessibility features in
MathML that
the example doesn't use).

I'd suggest that that example would best be done in the pure text form
above,  or with
<sup> elements, and more complex formulae should be done with an image with
a pure
text alternative.  (Even at a character level, it is not safe to assume that
browsers understand
Unicode maths and greek symbols, and misrepresenting characters using the
Symbol font is
very bad practice.)


The MathML source for this was:
<math>
  <mrow>
    <mi>y</mi>
    <mo>=</mo>
    <mi></mi>
    <mfrac href="http://www.w3.org/" xml:link="simple">
      <mn>1</mn>
      <msqrt>
        <mrow>
          <msup>
            <mi>x</mi>
            <mn>2</mn>
          </msup>
          <mo>+</mo>
          <mn>1</mn>
        </mrow>
      </msqrt>
    </mfrac>
  </mrow>
</math>

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Received on Tuesday, 8 August 2000 08:43:28 GMT

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