[html4all] CANVAS (was Discussion: "Accept requirement for immediate mode graphics a la canvas element")

[John Foliot]

Charles McCathieNevile wrote:

>> However, the real question is "Does <canvas> allow
>> for fallback content at all?", and the draft spec.
>> totally fails to clarify this.
> 
> As far as I can see it does so. Otherwise I would be raising hell -
> as an implementor of canvas, we need this. In any case, it should
> never be allowed forward without doing so.
> 

Well, the Draft Spec states:

"When authors use the canvas element, they should also provide content that,
when presented to the user, conveys essentially the same function or purpose
as the bitmap canvas. This content may be placed as content of the canvas
element. The contents of the canvas element, if any, are the element's
fallback content."
[http://www.whatwg.org/specs/web-apps/current-work/#the-canvas]

...which to me seems somewhat circular, without really specifying how or
what.  Breaking down the above, I would surmise that "...content that, when
presented to the user, conveys essentially the same function or purpose as
the bitmap canvas..." means a textual alternative (but, oh wait, isn't ALT
sometimes optional?... But I digress).  However the spec does not state this
explicitly, nor does the spec indicate that the element can even take on the
attribute of ALT; currently the only indicated attributes are height and
width.

So question one to the draft editors then is, "*How* does the content author
specify this other (alternative) content?"

As I continue to read through the Draft Spec, I note with interest many code
examples, yet none of the current examples show an implementation of content
that "...conveys essentially the same function or purpose as the bitmap
canvas..."

So question two would be, "Can we have an example that specifically and
explicitly shows authors *how* to provide this essential content?"

Finally, as an addendum, I would humbly suggest that the statement "...they
should also provide content that..." be re-written to state "...they MUST
also provide content that...", if we are to ensure universal access.
However, given the raging debate over ALT, I won't hold my breath.

Colleagues, am I missing something here?

JF