This Wiki page is edited by participants of the HTML Accessibility Task Force. It does not necessarily represent consensus and it may have incorrect information or information that is not supported by other Task Force participants, WAI, or W3C. It may also have some very useful information.
Longdesc-comments
Contents
- 1 Last Call Comments
- 2 Old bugs
Last Call Comments
Guy Moreau (Tuesday, 16 July)
Bug 23287 strengthen requirement for user access to longdesc
Proposed response to Guy
No. Constraining user interaction very much is probably a bad idea until we have more experience. There are also viable implementation strategies which use an interaction very different from that of ordinary links (e.g. the interaction in the Tell Me More extension).
Alternate version
Guy,
Thanks for your feedback. The Task Force has considered your suggestion to more explicitly define the behavior requirements on User Agents for accessing longdesc. We agree that discoverability is a key component in the success of longdesc, which is why we listed it in the Requirements section. However, the Task Force has decided to allow User Agents the flexibility to develop innovative solutions for users to discover and interact with longdesc content. There are known implementation strategies that would not meet the restriction you suggested in your comment, such as that used by the TellMeMore extension, or the ability to provide the description directly in a "popup window". Innovative solutions such as these would not be possible if the specification required any particular solution.
Richards, Jan (Tuesday, 16 July)
Bug 23288 Reference for Authoring and Repair
James Craig (Tuesday, 16 July)
Bug 23291 add statements about when longdesc is inapproppriate
Related discussion on MathML
Related discussion on SVG Accessibility
Proposed response to James and Mathew
The use of longdesc is not ipso facto inappropriate in these cases, as it provides discoverability, and in certain situations provides access that is otherwise unavailable. However, it is clearly inappropriate to simply rely on longdesc instead of, for example, providing a MathML version of mathematical content, or ensuring that an SVG image uses the accessibility features of the format.
A statement to that effect should be added as informative advice in the section on Authoring requirements.
Alternate version - Janina
The use of longdesc is not ipso facto inappropriate in these cases you cite, as it provides discoverability, and in certain situations provides access that is otherwise unavailable. However, we agree that it is inappropriate to rely on longdesc instead of providing supporting markup where standards exist to support accessibility directly in graphic formats, e.g. instead of providing a MathML version of mathematical content, or instead of ensuring that an SVG image uses the accessibility features of SVG.
We have added an informative statement to this effect in the section on Authoring requirements. (see suggested spec text)
Alternate version - Mark
James and Mathew,
Thanks for taking the time to provide feedback on the longdesc specification. We agree that it would be inappropriate to rely solely on longdesc where standards exist to support accessibility more directly, instead of e.g. providing a MathML version of mathematical content, or using the native accessibility features of SVG. However, even in these cases many users of current-generation technologies which don't support those standards well can benefit from the discoverability and access provided by longdesc.
We disagree that an "ordinary" link provides the same discoverability as longdesc in the general case.
We have added the following text to the section on Authoring requirements to further clarify when longdesc is appropriate:
Suggested Spec Addition
Authors SHOULD NOT rely solely on longdesc where standards exist to provide direct, structured access. Note: (informative) For example a MathML version of mathematical content, or an SVG image that uses the accessibility features of SVG, can provide better accessibility to users with appropriate technology. In such cases, it is appropriate to use longdesc as a fallback strategy, in combination with more modern techniques.
Matthew Turvey (Tuesday, 16 July)
Bug 23291 add statements about when longdesc is inapproppriate - See above
- Re: Call for Review: HTML5 Image Description Extension (longdesc) Last Call (Related to comment from James Craig)
Andrew Kirkpatrick (Friday, 23 August)
Bug 23293 Require descriptions which are not while documents to be well-formed fragments
Bug 23292 User agent requirements for handling same page references
Proposed response
There is a suggestion in the document (*should*) that authors make descriptions well-formed fragments, but there is currently no corresponding requirement on user agents. For now, we will simply leave it as a best practice
Alternative response
Andrew,
Thanks for taking the time to consider longdesc in the context of specific WCAG techniques, specifically the behavior of user agents when a longdesc refers to a document fragment. The Task Force has intentionally refrained from requiring any specific behavior in this respect from user agents. There is a requirement in the document that authors SHOULD put descriptions in well-formed fragments (which may include an entire page). Because there is existing, and will likely continue to be new content that does not meet this requirement, we do not propose a corresponding requirement on user agents.
Shawn Henry/EOWG (Monday, 16 September)
Bug 23289 Suggested editorial fixes from EOWG
Proposed Response
Dear EOWG,
Thank you for your review. We found the vast majority of your suggestions very helpful and will incorporate them into the specification. Below are replies to individual suggestions where we feel it is important to clarify, or where we will not be incorporating your suggestions.
Add "This section is non-normative." to main non-normative sections. (We see a sentence about this later, but are concerned it's not clear enough. For example, the first section under 3. The longdesc attribute <http://www.w3.org/TR/html-longdesc/#longdesc> starts with a sentence that is not clearly a "Note" (e.g., not offset, marked up, and preceded with "Note:"...")
In the specific example, that statement is not normative, so instead we will remove the words "Note that" an the beginning. We believe that all other non-normative sections are identified as such, but will double-check.
Introduction: Provide a little context at the beginning, briefly explaining what long descriptions are. For suggested wording, see the Image concepts page <http://www.w3.org/WAI/tutorials/images/> (note the lower sections have "Why is this important" and "How to make images accessible") and Complex images<http://www.w3.org/WAI/tutorials/images/complex>. Consider pointing to these pages for more information
We will add more information in the introduction as suggested. The pages referenced do not appear stable enough to be a reference in this document, so we will not be linking to them.
Suggested edit to the paragraph under Use Cases and Requirements <http://www.w3.org/TR/html-longdesc/#UCnR>: "Text alternatives are required so that users can successfully understand and interact with images even if they cannot see, or see well. The alt attribute is designed to contain a short description. This is sufficient for most images, and should provide enough information to ensure that users understand the image's purpose. Some images contain more information than can effectively be provided in a short description. The longdesc attribute is designed for longer descriptions to meet use cases such as the following." —
Whether an image needs a long description can depend on context as well as the image itself. Alt is designed to provide a functional replacement text, not a short description. In many cases text alternatives are not necessary to support interaction. We therefore do not propose to adopt this edit.
Current wording: "This document does not define the term "accessible" nor accessibility, but uses them with the sense they have in [WCAG]" Change reference from WCAG to Introduction to Web Accessibility <http://www.w3.org/WAI/intro/accessibility> then can say more directly: "This document does not define the terms "accessible" or "accessibility"; it uses them as explained in Introduction to Web Accessibility.
That document referenced has no apparent stability or persistence policy. For a reference we prefer to use a W3C Recommendation which has both.
The Abstract says "Note that by allowing a hyperlink inside another one, this document explicitly redefines the HTML concept of hyperlink in a limited set of circumstances." Is this point clearly addressed in the main document?
Yes. It is in the section mentioned in your first comment above (Section 3: <http://www.w3.org/TR/html-longdesc/#longdesc>. We propose to remove the confusing lead-in "Note that".
Charles McCathie Nevile (Monday, 16 September)
Bug 23290 Additional use case for discoverability of long descriptions
Proposed Response to Yandex
Dear Charles,
We propose to add two use cases, as follows.
Image search Many search engines provide an option to search for images and present the results out of context. The ability to discover and process identified descriptions allows search engines to improve the source material they use to support text-based queries for images. Requires: Discoverability
Describing images Image search tools identify multiple copies of the same image. Where a search tool can identify a description of an image, this can be provided to the user as a description for any copies of that image. Requires: Discoverability