- From: Laura Carlson <laura.lee.carlson@gmail.com>
- Date: Thu, 9 Sep 2010 18:13:03 -0500
- To: Joshue O Connor <joshue.oconnor@cfit.ie>
- Cc: "HTML Accessibility Task Force <public-html-a11y@w3.org> W3C WAI-XTECH" <wai-xtech@w3.org>, Sam Ruby <rubys@intertwingly.net>, Judy Brewer <jbrewer@w3.org>
Hi Josh > I have come across a couple of interesting @longdesc use cases. I have researched some more: http://www.d.umn.edu/~lcarlson/research/ld.html If anyone knows of others, please let me know. Thanks. Best Regards, Laura > I have come across a couple of interesting @longdesc use cases. The > first is by Laura Carlson which used "A11y Resolved Bug Comparisons" > graphs and pie charts. Describing a pie chart and graph like the > examples Laura provide would be extremely difficult without an attribute > like @longdesc, if you don't want the descriptions to appear inline. [1] > > To expand on this problem, the need for an off page long descriptor is > made even clearer in the following example from 2006 (courtesy of Prof. > Barry McMullin of DCU) which he describes as a "Double-negative use > case". [2] > > To explain - I will quote Barry directly from the CFIT website. > > "Double-negative" because longdesc is not being used here — but I would > have liked to use it, and its use would have been absolutely > appropriate! It's just that weak user-agent support meant that using it > would potentially have left the long description actually unavailable to > people who might benefit from it. So instead, I decided to compromise > (somewhat) the experience of people who already could perceive the > graphical image perfectly well, and exposed the long description for all > users (even though it is redundant for the majority). This decision > then, logically, had the further effect of requiring an explanation — > for those majority users — of what a long description is and why — which > explanation, in turn, is redundant for those users who would normally > actually benefit from a long description! > > I humbly suggest that such a convoluted (nay, "traumatic"!) design > decision — genuinely existing "in the wild" — should count as legitimate > evidence of the use-case-need for longdesc!?" [3] > > To me the above example, compounds the first and illustrates that an off > page long descriptor is very much needed but due to the authors concerns > about UA support etc he decided /not/ to use it. This implies that: > > 1) A long descriptor, that can potentially reference a URI and can be > recognised and handled in a way that is conducive to a positive user > experience for an AT user is actually needed. > > 1) The consequences of having to include a very verbose description > inline can be problematic in terms of page bloat, potential perceived > complexity for users with cognitive disabilities and possibly other > usability issues, such as general confusion as to the descriptions > purpose for non-users of AT. > > Josh > > [1] http://www.d.umn.edu/~lcarlson/html5bugchart/20100821/ > [2] http://www.aishe.org/readings/2007-1/No-14.html#x20-19300014.6 > [3] http://www.cfit.ie/news-and-commentary-archive/525-longdesc-rip > > > -- Laura L. Carlson
Received on Thursday, 9 September 2010 23:13:32 UTC