Re: advice on alt text for image maps

hi leif,

will think on your comments, agree as Jukka pointed out there needs to be
better advice for alt text for images used as image maps.

--

Regards

SteveF
HTML 5.1 <http://www.w3.org/html/wg/drafts/html/master/>


On 28 December 2013 05:29, Leif Halvard Silli <
xn--mlform-iua@xn--mlform-iua.no> wrote:

> Jukka K. Korpela, Thu, 26 Dec 2013 23:34:57 +0200:
> > 2013-12-24 19:26, Steve Faulkner wrote:
>
> >> I have made some modifications to the example:
> >>
> >>
>
> http://www.w3.org/html/wg/drafts/html/master/embedded-content-0.html#image-maps-0
>
> > There's no general guideline for writing the alt attribute,
> > though. [...]
>
> Great stuff, Jukka. You’ve gotten me to think. I hope Steve considers
> your ideas, which I hereby wish to expand on a little.
>
>   [ Snipping to the general guideline you propose: ]
>
> >> If an img element has a usemap attribute  [ … ] it acts as a
> >> caption for the collection of the alt attributes of the area elements
>
> Put that in the spec! To view the alternative text of the usemap image
> as a caption for the line of area elements, is a good, general
> authoring guideline.
>
> > How does the text "Map of Katoomba" help [...]
> > In this case, alt="" would seem to be the appropriate
>
> That the alternative text can be set to empty whenever a caption for
> the area element links is unnecessary, is an intriguing part of your
> proposal. Some supportive observations:
>
> A) Two, slightly different, presentation modes appear to exist:
>    1. Image-map-mode is triggered by alt-text presence. Image-map-
>       mode is characterized by an ”Image map!” + alt-text
>       announcement that precedes presentation of the <area> links.
>    2. Line-of-links-mode is triggered by empty as well as omitted
>       alt-text. Line-of-links-mode is characterized by the lack
>       of any Image Map announcment (e.g. check VoiceOver+Safari)
>       Unique for this mode, Lynx generates its own text ([USEMAP])
>       regardless of whether the alt-text is empty or omitted.
>
> B) HTML5’s WAI-ARIA section specifies that empty @alt triggers
>    presentation role. Use of @usemap attribute does not matter.
>
> C) Use cases for not announcing a usemap image as an image
>    map do exist. E.g. image maps used for site navigation as
>    well as the example Jukka described.
>
> D) An image-map image may be as varied as a non-image-map image -
>    it could be a logo, text, portrait - even decorative. One might
>    as well use <figure> with image maps, and supposedly omit @alt.
>    Which justifies more than just a ”always use alt-text” advice.
>
> E) WAI-ARIA gives us a third mode - image mode:
>      *  <img role="img" src="file" alt="Text" usemap=#map />
>    Here, the area elements get presented as a line of consecutive
>    links without preceding image-map announcement. But, instead of
>    being silent about the image, role="img" causes the image to be
>    announced as an image (vs announced as image map or not at all).
>
> F) It seems that image-map images could be viewed as having their
>    own, non-ARIA defined ”role”, much like e.g. <table> have no
>    corresponding ARIA role. By setting the alternative text to
>    empty, the role is changed to role="presentation". By setting
>    role="img", the image-map image is set to image. Again, much
>    like the <table> may be changed from its native, non-ARIA-
>    defined role to e.g. presentation role (via role=presentation)
>    as well as to other, specific roles (like grid).
>
> As a conclusion, the advice on how to author alt text for usemap images
> could be split in 3 parts based on whether the usemap image should have
> native role (when alternative text is present), presentation role (when
> the native role is overruled by empty or omitted alternative text or
> role="presentation") or image role (when the native role is overruled
> via role="img").
> --
> leif halvard silli