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

From: Jon Gunderson <jongund@uiuc.edu>
Date: Thu, 30 May 2002 16:10:21 -0500
Message-Id: <>
To: "Tim Lacy" <timla@microsoft.com>, "Ian B. Jacobs" <ij@w3.org>, <w3c-wai-ua@w3.org>

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

JRG: If you don't recognize a content type you will not be able to render 
it anyway.  Can IE render content that it doesn't recognize?

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

JRG: We only require that the user agent control based on content type 
(animated gif) or markup known to blink (BLINK element).  The user agent 
does not need to calculate or analyze content to see if it is blinking.

>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

Jon Gunderson, Ph.D., ATP
Coordinator of Assistive Communication and Information Technology
Division of Rehabilitation - Education Services
College of Applied Life Studies
University of Illinois at Urbana/Champaign
1207 S. Oak Street, Champaign, IL  61820

Voice: (217) 244-5870
Fax: (217) 333-0248

E-mail: jongund@uiuc.edu

WWW: http://www.staff.uiuc.edu/~jongund
WWW: http://www.w3.org/wai/ua
Received on Thursday, 30 May 2002 18:42:12 UTC

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