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Re: <canvas> Usage (Was: Begin discussions for pushing Last Call into 2010)

From: Ian Hickson <ian@hixie.ch>
Date: Sat, 15 Aug 2009 21:51:07 +0000 (UTC)
To: Smylers <Smylers@stripey.com>
Cc: public-html@w3.org
Message-ID: <Pine.LNX.4.62.0908152148110.28566@hixie.dreamhostps.com>
On Sat, 15 Aug 2009, Smylers wrote:
> Shelley Powers writes:
> > I particularly liked David Hyatt's response to the discussion, where
> > he called the Canvas object, and its associated API, nothing more than
> > a "dynamic <img> "[6]. If that's all the Canvas was to be, then yes,
> > inclusion in the HTML WG was appropriate. But Canvas, or I should say
> > the 2D API, is much more than just a "dynamic image".
> >
> > [6] http://lists.w3.org/Archives/Public/public-html/2007Apr/0324.html
> Could we define <canvas> simply to be a dynamic <img> -- that is, to
> make other uses, such as Bespin, non-conforming?
> In addition to the accessibility concerns of Bespin there are several
> other problems of using <canvas> to create user interfaces; Philip
> mentioned several in this message:
>   http://lists.w3.org/Archives/Public/public-html/2009Feb/0432.html
> If <canvas> were only used as a dynamic <img> then it would presumably
> be straightforward for authors to provide a non-graphical alternative:
> it would be the same as the alt text would be were the image generated
> server side and served as an <img>.

The spec already says:

| Authors should not use the canvas element in a document when a more 
| suitable element is available. [...]
| When authors use the canvas element, they must also provide content 
| that, when presented to the user, conveys essentially the same function 
| or purpose as the bitmap canvas. 

I don't know how stronger we can make this.

We can't go as far as you're suggesting, since it would make things like 
games non-conforming, and they're one of the main use cases.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Saturday, 15 August 2009 21:51:44 UTC

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