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Action-258 Help users avoid flashing that could cause seizures.

From: Jim Allan <jimallan@tsbvi.edu>
Date: Mon, 11 Jan 2010 10:37:05 -0600
To: "'UAWG list'" <w3c-wai-ua@w3.org>
Message-ID: <07f901ca92dc$4f6db250$ee4916f0$@edu>
We have had much discussion on Action-258  rewriting 4.4.x

<original from [1]>
4.4.1 Below Threshold: The user interface never violates the general flash
or red flash thresholds. (Level A)

4.4.2 Three Flashes: No part of the user interface ever flashes more than
three times in any one second period. (Level AAA) [WCAG 2.0]
</original>

After much discussion on the list (see below), and several conversations
between Greg and myself we arrived at

<proposal>
4.4.1 Three Flashes or Below Threshold: In its default configuration, the
user agent does not contain any recognized items that flash more than three
times in any one second period, unless the flash is below the general flash
and red flash thresholds. (Level A)

4.4.2 Three Flashes: In its default configuration, the user agent does not
contain any recognized items that flash more than three times in any one
second period (regardless of whether not the flash is below the general
flash and red flash thresholds). (Level AAA)

NOTE: See 4.9.7 regarding user ability to stop/pause/resume time-based
media, including flashing.

(Best Practices document will also include a suggestion that the user agent
may allow the user to specify a maximum rate for recognized flashing slower
than 3 times per second.)
</proposal>

And a proposal to change 4.9.7 from 

<original>
4.9.7 Stop/Pause/Resume Multimedia: The user can stop, pause, and resume
rendered audio and animation content (including video and animated images)
or user interface items (such as animated icons or scrolling status text)
that last three or more seconds at their default playback rate. (Level A)
</original>

into:

<proposal>
4.9.7 Stop/Pause/Resume Time-based Media: The user can stop, pause, and
resume recognized audio and animation items that last three or more seconds
at their default playback rate. (This applies to both user agent user
interface and to rendered content.) (Level A)

(Note that this version says "recognized" instead of "rendered", as we feel
the former (original version) implies the latter (proposed version), and is
in fact an overlapping set: the set of animations rendered overlaps the set
of animations recognized, because the former includes things rendered but
not recognized, such as Shockwave and javascript-driven animations, while
the latter includes things recognized but not "rendered", such as the user
agent's own UI given the word "rendered" is defined in this document as only
applying to content.)
</proposal>

(More accurate, legalistic wording would be "The user agent user interface
does not contain, and the user agent does not render content that." but
that's quite a mouthful.)


1.
http://www.w3.org/WAI/UA/2009/ED-IMPLEMENTING-UAAG20-20091105/#gl-prevent-fl
ash  (using the techniques document since it is easier to deep link into)
2. http://lists.w3.org/Archives/Public/w3c-wai-ua/2009OctDec/0100.html 
3. http://lists.w3.org/Archives/Public/w3c-wai-ua/2009OctDec/0101.html
4. http://lists.w3.org/Archives/Public/w3c-wai-ua/2009OctDec/0102.html
5. http://lists.w3.org/Archives/Public/w3c-wai-ua/2009OctDec/0103.html
6. http://www.w3.org/2009/12/17-ua-minutes.html#action02

Jim Allan, Accessibility Coordinator & Webmaster
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
"We shape our tools and thereafter our tools shape us." McLuhan, 1964
Received on Monday, 11 January 2010 16:37:46 GMT

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