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RE: [Issue 521] Requirements involving "all" formats

From: Tim Lacy <timla@microsoft.com>
Date: Thu, 30 May 2002 12:39:24 -0700
Message-ID: <DE8C2EEE23641143A8C0CD7705C26AE70408D0C3@red-msg-03.redmond.corp.microsoft.com>
To: "Ian B. Jacobs" <ij@w3.org>, <w3c-wai-ua@w3.org>

I have several issues with all of this:

1) It presumes that the UA has prior knowledge of all possible
(including not-yet-determined) content type definitions/declarations.

2) Animated and blinking text can be created in ways that are
difficult/impossible to accurately detect.

OK, two issues

-----Original Message-----
From: Ian B. Jacobs [mailto:ij@w3.org] 
Sent: Monday, May 27, 2002 11:07 AM
To: w3c-wai-ua@w3.org
Subject: [Issue 521] Requirements involving "all" formats


Hello all,

At the 11 April 2002 teleconference [1], I took an action regarding
issue 521 [2] to identify checkpoints whose requirements apply
independent of formats that are part of the conformance claim.

I propose that for the following checkpoints (reference UAAG 1.0 12 Sep
2001 draft [3]), the format requirements apply as follows:

   3.1 Toggle background images: Applies for all image formats.
   3.2 Toggle audio, video, animated images: Applies for
       all audio, video, and animated image formats.
   3.3 Toggle animated/blinking text: Applies to all formats.
   3.7 Toggle images. Applies to all image formats.
   4.9 Global volume control. Applies to all audio formats.

I tried to come up with a model that would allow me to choose some
checkpoints and not others, but I couldn't come up with anything
satisfying. One feature of the above checkpoints is that I think it's
possible to recognize images, audio, etc. by content type, independent
of format details.

Proposed changes to the specification:

  1) Indicate at the beginning of the section on conformance that
  a user agent doesn't have to satisfy the checkpoints for EVERY
  implemented format, only those that are part of the conformance
  claim with the following exceptions:

     - If the conformance claim includes the VisualText
       content type label, the user agent must satisfy
       3.3 for all formats.
     - If the conformance claim includes the Image content
       type label, the user agent must satisfy 3.1 and 3.7 for
       all image formats.
     - If the conformance claim includes one of the Audio, Video,
       or Animation  content type labels, the user agent must
       satisfy 3.2 for all audio, video, or animation formats,
       respectively.
     - If the conformance claim includes the Audio
       content type label, the user agent must satisfy
       4.9 for all sources of audio.

  3) Update the relevant content type label defintions with the
     same information.

Note: I thought that it might be useful to modify the checkpoints
themselves to say "for all image formats" etc. Upon experimentation, I
find that it makes the checkpoints unduly complicated.

  - Ian

[1] http://lists.w3.org/Archives/Public/w3c-wai-ua/2002AprJun/0049
[2] http://www.w3.org/WAI/UA/issues/issues-linear-cr2#521
[3] http://www.w3.org/TR/2001/CR-UAAG10-20010912/

-- 
Ian Jacobs (ij@w3.org)   http://www.w3.org/People/Jacobs
Tel:                     +1 718 260-9447
Received on Thursday, 30 May 2002 15:40:20 GMT

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