- From: Doug Schepers <schepers@w3.org>
- Date: Tue, 22 Feb 2011 23:51:05 -0500
- To: Courtney Christensen <courtney.christensen@viewplus.com>
- CC: www-svg@w3.org
Hi, Courtney- Thanks for bringing this up here. I agree that for SVG images referenced in an <img> element, all the <title> and <desc> text content is overkill, but for <iframe>, <object>, etc., the user should be able to drill down into the sub-elements. We will be discussing accessibility a bit at our SVG WG face-to-face meeting next week, so I will report back on what's discussed. Regards- -Doug Schepers W3C Team Contact, SVG, WebApps, and Web Events WGs Courtney Christensen wrote (on 2/18/11 4:06 PM): > I have recently been discussing some SVG accessibility concerns with > Doug Schepers. From this discussion, the following WebKit bug report was > filed. But these are general issues, not specific to WebKit. It seems > that there needs to be a discussion to better define how assistive > user-agents behave, especially in SVG islands in HTML. > > The bug report shown below focuses on how <title> and <desc> tags should > be exposed to screen readers -- suggesting that the rootmost <title> > (and <desc>?) element(s) act as an <img>'s ALT tag would. Doug says > below that this is discussed, but not normatively defined. > > And indeed, using current browsers and screen readers, I have found very > little support for this. The "odd man out" is IE9, which exposes ALL > elements with <title>s to the screen-reader's buffer, regardless of > depth. It also provides this info on mouseover. (Mentioned below as > possible "overkill") > > Foreseeing this interference with authorial intent, link [3] below > strongly suggests using role="tooltip" for elements which are to expose > their <title>s. I've found NO support for this yet; instead browsers > expose everything with a <title> element, usually in the form of a popup > tooltip. > > Even if this functionality were implemented, how exactly would this map > to traversing the SVG DOM? Doug's WebKit comment: > --------------------------------------------------------------------------- > From WebKit Bug 54357: > https://bugs.webkit.org/show_bug.cgi?id=54357#c2 > --------------------------------------------------------------------------- > From Doug Schepers 2011-02-16 20:14:32 PST > >> There is presently no standard for what screen readers should do with > inline >> SVG islands. > > The W3C Note 'Accessibility Features of SVG' [1], from 2000, does > discuss SVG accessibility, but as mentioned, it does not normatively > define precisely what screen readers should do. > > Also, there are some specific suggestions in the SVG Tiny 1.2 spec [2] > for both authoring content and screen readers, but it could use more > precise and normative instructions. The SVG WG plans to do this in an > upcoming SVG Accessibility specification, and as part of SVG 2. > > >> We are spearheading an effort by DAISY and the W3C SVG Working >> Group to create SVG accessibility standards. One proposal is that screen >> readers read the root-level <title> and <desc>. > > This is suggested in SVG, most recently in SVG Tiny 1.2 [3]. > > >> This is most elegantly >> accomplished by having those two properties appear separately in the >> accessible DOM elements exposed to screen readers. Presently IE9 does this >> but also exposes <title> and <desc> of all graphical objects - which we >> believe is overkill and annoying. We have asked Microsoft to change this. > > If all the elements are exposed at once, this is indeed overkill, but if > they are exposed as discrete elements when the immediate parent is in > focus, then it is appropriate, just as progressively exposing any > structure text content (e.g. in HTML) is useful. > > The key is in defining the navigation behavior so users can explore the > content, or skip over it, at their own discretion. This will take > coordination between the author of the content structure and the screen > reader software, though a well-defined algorithm. > > >> Other browsers seem to expose nothing in SVG to screen readers while >> traversing a document linearly. We are requesting that all browsers be >> updated to include this feature, and we hope that Safari can be updated to >> do this. > > We also need to consider the order in which text content is made > available (presumably document order should be the default, with > possible overrides), and when labels should be used instead of 'title' > and 'desc' elements. > > > This should all be discussed on the public SVG mailing list, > www-svg@w3.org, and standardized as part of SVG. > > [1] http://www.w3.org/TR/SVG-access/ > [2] http://www.w3.org/TR/SVGTiny12/access.html > [3] http://www.w3.org/TR/SVGTiny12/struct.html#uiTitleDescBehavior
Received on Wednesday, 23 February 2011 04:51:07 UTC