Re: <canvas> and the 2D context API (was RE: Begin discussions for pushing Last Call into 2010)

On Aug 12, 2009, at 5:56 PM, Shelley Powers wrote:

>
> If we were to split the API into a separate document, could it  
> progress at a different pace than the main HTML 5 specification?

To a limited extent, yes. But HTML5 would likely have a normative  
reference to a Canvas API spec, so there is a limit. Per W3C rules,  
you can't normatively reference a document that's more than one  
maturity level apart. So we couldn't go to CR (and thus couldn't enter  
LC) until the Canvas API draft reached Working Draft status, and we  
couldn't go to PR until the Canvas API draft reached CR.

> Could it also have a different editor or set of editors?

Yes. But I expect Ian is unlikely to remove the current  
CanvasRenderingContext2D section until someone demonstrates they can  
do the work by actually producing a viable separate draft. And I  
expect much of the Working Group would feel the same way.

> (Note though that even if we take out the 2D graphics context, the  
> element still belongs in the HTML spec, as it's part of the  
> language. So technically "<canvas>" still would be in the spec; just  
> the graphics context API would be taken out. One could argue that  
> that would lead to the spec being overly confusing to implementors,  
> who generally prefer things in one place to implement them, as it  
> leads to fewer "cracks between the specs".)"

I do think there is the risk of confusion in such a case.

> Now, I do agree that the Canvas _element_ belongs in the HTML  
> specification, but the API should be split out. Doing so would also  
> work in well with the ongoing effort to incorporate accessibility.

To the contrary, I think splitting out Canvas could harm the  
accessibility work, for reasons stated in my other email.


Generally speaking: Over the past two years, a number of people have  
expressed interest in the existence of a separate spec for the API,  
but no one has actually done it. The time window to produce a draft  
that could receive adequate consideration before Last Call is limited.  
I believe a quality draft would receive fair consideration. Note that  
this is considerably more complicated than just cut/pasting a big  
chunk of text out of HTML5. That would leave many dangling references  
and unclear definitions in both directions. But I believe that it is  
doable, and there would be some technical advantages to making the  
CanvasRenderingContext2D API more readily reusable. I also suspect Ian  
would consider doing the work himself post-HTML5, if no one else gets  
to it by then.

Personally, I don't think it's worth raising this as an issue until  
someone produces a draft or volunteers to do so on a reasonable  
deadline. This task has not really gone anywhere as a wishlist item.

Regards,
Maciej