- From: Steve Faulkner <faulkner.steve@gmail.com>
- Date: Sat, 4 Jan 2014 16:49:23 +0000
- To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
- Cc: "Jukka K. Korpela" <jukka.k.korpela@kolumbus.fi>, HTMLWG WG <public-html@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
- Message-ID: <CA+ri+V=Z1xCgcNkQCEzB3C9KkxoZ9N3fi5HkzmmWyNUzzdxVNQ@mail.gmail.com>
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
Received on Saturday, 4 January 2014 16:50:32 UTC