- From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
- Date: Mon, 13 Sep 2010 12:59:13 +0200
- To: Steven Faulkner <faulkner.steve@gmail.com>
- Cc: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>, public-html-a11y@w3.org
Steven Faulkner, Mon, 13 Sep 2010 11:04:47 +0100: >> "Better questions for getting screen reader user views on UI images >> might be:..." > > yes many better questions could be asked, but I am fairly certain the > screen reader users who responded (included a screen reader > developer, yahoo accessibility evangelist, a developer working on > drupal accessibility), understood the intent of the question. One of them said "unless it's a spacer or other * purely * stylistic image". I don't know was meant by "stylistic image". But I would think that an image that only represents text in a certain font, would fall into that category. >> "<button><img alt="Edit" src="pencil.png"></button>" >> "because the button text would be represented as just button text in >> the accessibility tree rather than as an image with a text >> alternative?" > > NO I would argue for the current behaviour: > The accessible tree (can be viewed using firefox DOM inspector) looks > like this: > > - pushbutton > name > bottle > -- graphic > name > bottle > When an AT such as JAWS encounters the button announces the button > role and its accessble name value (from the image alt text) it does > not announce the image. BUT the image is not removed by the browser > from the accessible tree. I don't think this is perfect answer: The author could provide the text inside an visually hidden adjacent <span> element and give the <img> role="presentation" via alt=<emptystring>. Voila. The benefit of the not-removed image would then be gone, since the image would in fact be removed. It is also backwards that one can set an image *with* empty alt to role="img" - without getting a error. Wheras role="presentation" is suitable as "validation godsend", as long as we are dealing with <img> ... [1] It is nice, when it works, that the image role isn't announced. But who knows how the AT works? E.g. you said that <a><img alt=foo></a> is typically announced as "link graphic foo", but that "link foo" would usually be better. [2] (As a matter of fact, VoiceOver does what you suggest!) Meanwhile, ARIA says that role="presentation": [3] ]] does not cause the content contained within the element to be removed from the accessible tree [[. So isn't the @alt text "content"? Yes it is. It is just as much content as the graphic itself. So it shouldn't be removed. After all: the reason alt="<empty>" causes role="presentatioN" is because the @alt is so significant w.r.t. to what the IMG represents! Bug 10614. But, regardless, if the intention is that role="presentation" hides the image, are the other workarounds? Yes, this works (but the @alt text shoudl, according to Richard [1], be flagged an error): <button role="button" aria-labelledby="pencil" > <img id="pencil" role="presentation" alt="Edit" src="pencil.png"> </button> [1] http://lists.w3.org/Archives/Public/wai-xtech/2010Aug/0073 [2] http://lists.w3.org/Archives/Public/wai-xtech/2010Aug/0014 [3] http://www.w3.org/WAI.new/PF/aria/complete#presentation [4] http://www.w3.org/Bugs/Public/show_bug.cgi?id=10614 -- leif halvard silli
Received on Monday, 13 September 2010 10:59:47 UTC