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Re: img@relaxed CP [was: CfC: Close ISSUE-206: meta-generator by Amicable Resolution]

From: Steve Faulkner <faulkner.steve@gmail.com>
Date: Sat, 4 Aug 2012 20:33:20 +0100
Message-ID: <CA+ri+VmCb7zew5vKfyit4mWgvSWfo5PwcL5+DBn99O-MtWrt_g@mail.gmail.com>
To: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>
Cc: "Michael[tm] Smith" <mike@w3.org>, public-html@w3.org, HTML Accessibility Task Force <public-html-a11y@w3.org>, John Foliot <john@foliot.ca>
hi ben,

Firefox for example provides a flag (IsProbablyForLayout [1])
indicating whether a table is likely to be layout or not based on a
range of factors, so yes it could well be worthwhile taking into
account a number of properties of the image apart from the attribute
under discussion to produce a similar indicator.

[1] http://mxr.mozilla.org/mozilla-central/ident?i=IsProbablyForLayout

On 4 August 2012 20:13, Benjamin Hawkes-Lewis
<bhawkeslewis@googlemail.com> wrote:
> On Sat, Aug 4, 2012 at 6:54 PM, Steve Faulkner <faulkner.steve@gmail.com> wrote:
>>>I doubt a user agent would factor the presence of an attribute such as
>>>@relaxed into its decision to indicate or not indicate the presence of
>>>a particular image without a provided text alternative. In particular,
>>>I doubt user agents which provide configuration for indicating or not
>>>indicating such images (such as VoiceOver which allows users to ask it
>>>to announce all images or only images "with descriptions") would
>>>distinguish <img> and <img relaxed> as distinct categories in their
>>>configuration UI.
>> I don't presume to make such judgements without first having defined a
>> proposed mechanism and sought feedback from end users and the
>> accessibility engineers implementing such a mechanism in user agents.
> Well, it's up to you if you feel they're likely enough to use the flag
> to spend your cycles and theirs to see if they want the flag mentioned
> in your mapping guide :)
> You might want to ask them at the same time if there's additional
> information that could help them make decisions about whether to alert
> a user to an image's presence, such as URL, intrinsic (as opposed to
> rendered) size, transparency, color count, and repetition statistics,
> that they might want surfaced.
> IAccessibleImage (from IA2) doesn't have much in the way of relevant fields:
> http://accessibility.linuxfoundation.org/a11yspecs/ia2/docs/html/interface_i_accessible_image-members.html
> But maybe AT in practice just pulls out information from the DOM and
> CSSOM via references in the IA2 object. Or maybe their algorithms for
> deciding whether to alert users to images or not aren't all that
> sophisticated yet. Or maybe they'd prefer browsers did the work. Don't
> see anything about this grepping the NVDA codebase for example.
> --
> Benjamin Hawkes-Lewis

with regards

Steve Faulkner
Technical Director - TPG

www.paciellogroup.com | www.HTML5accessibility.com |
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Received on Saturday, 4 August 2012 19:34:29 UTC

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