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Re: method for providing programmatically associated long description

From: Steven Faulkner <faulkner.steve@gmail.com>
Date: Wed, 25 Aug 2010 16:07:52 +0100
Message-ID: <AANLkTi=14gsK7SMYUoU9t8T4wr6DSv3CfH4WGGs1CFRM@mail.gmail.com>
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Cc: HTMLWG WG <public-html@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Hi leif,

The @coords in your example, in effect, makes the <img> a
link, for all users. The intention? Also, it is tedious to have create those
@coords.

Noparticular intention it was a quickly mosked up example. Besides I do not
believe it is a requirement for a programmatically associated long
description only to be available for some users is it? I certainly don't
read that requirement in WCAG 2.0.

But I am sure if an author wanted to achieve it they could. perhaps a 1px
region would do it.

As far as it being tedious creating the co-ordinates, most html code editors
provide a GUI for creating image map regions, it took me a few moments to
create the one in the example. And what percentage of images require a long
description?


> Why not simply wrap the <img> in an anchor element, then?

the advantage this has is that it leaves the image alt attribute free for
the text alternative for the image, while the area alt labels the link to
the longdesc and the link to the longdesc is programmatically associated.

regards
Stevef
On 25 August 2010 13:52, Leif Halvard Silli <
xn--mlform-iua@xn--mlform-iua.no> wrote:

> Steven Faulkner, Wed, 25 Aug 2010 13:00:56 +0100:
> > Hi all,
> > another possible method for providjng a programmatically associated
> > long description for an image:
> >
> > <img src="images/table.gif" alt="Bar Chart showing average rainfall
> > in millimetres by country and season."  usemap="#longdesc">
> > <map name="longdesc">
> > <area alt="bar chart long description" coords="2,318,404,341"
> > href="details.html#table">
> > </map>
>
> The @coords in your example, in effect, makes the <img>/<object> a
> link, for all users. The intention? Also, it is tedious to have create
> those @coords.  Why not simply wrap the <img> in an anchor element,
> then?
>
> That said, you probably don't need to use @coords: I just I did some
> testing of VoiceOver, Jaws and NVDA (with IE, Webkit, Opera, Firefox),
> to check whether or not they always consider an <area> element a link.
> [1] (Short answer is that they don't see it as a link, whenever one
> uses area{visibility:hidden}.) And if I remember correctly, then none
> of them require the @coords attribute to be used, in order consider the
> <area> element a link. Also, HTML5 does not require the @coords
> attribute for <area> - if I can trust Validator.nu.
>
> So, in a summary, if authors can skip the @coords attribute, then this
> method becomes simpler to use.
>
> [1]
>
> http://microformats.org/discuss/mail/microformats-new/2010-August/002166.html
> --
> leif halvard silli
>



-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

www.paciellogroup.com | www.wat-c.org
Web Accessibility Toolbar -
http://www.paciellogroup.com/resources/wat-ie-about.html
Received on Wednesday, 25 August 2010 15:08:47 UTC

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