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RE: another example of HTML 5 canvas with interactive UI elements.

From: John Foliot <jfoliot@stanford.edu>
Date: Thu, 9 Jul 2009 16:55:09 -0700 (PDT)
To: <joshue.oconnor@cfit.ie>, "'Lachlan Hunt'" <lachlan.hunt@lachy.id.au>
Cc: "'HTMLWG WG'" <public-html@w3.org>, "'W3C WAI-XTECH'" <wai-xtech@w3.org>
Message-ID: <01ce01ca00f0$b0bbd010$12337030$@edu>
Lachlan Hunt wrote:
> 
> > One relatively simple way to make that particular example accessible
> > would be to make use of an image map.  The technique could work
> > something like this.
> >
> > Overlay the canvas with a stretched transparent image of the same size
> > has the canvas.  The image then needs to be associated with an image
> map.


You see, it's responses like this that simply leave some (like me) shaking
their head in absolute disbelief.  

What size is this stretched image? 1024 X 768? 800 X 600? Something else?
How are you going to know?  Or are you suggesting that a JS script
determines view-port size, and then dynamically re-sizes your transparent
1 X 1 pixel gif (still with transparent gifs? Or will it be a 1 X 1
transparent PNG instead?) to cover the viewport, upon which more
javascript then writes shifting icons complete with dynamically re-written
<area> coordinates.  Really? And this is "relatively simple" to do?  Wow.




> >
> > For each icon represented on the canvas, an associated <area> element
> > needs to be created by the script with its co-ordinates set to the
> > position of the corresponding icon.  Appropriate alternate text is
> also
> > needed for each one.  When icons on the canvas are moved, the image
> map
> > areas need to be dynamically updated also.  With each area being
> > focussable, this would add support for keyboard navigation.


OK, so how many developers out there do you think are going to do
duplicate amount of work (as you just described), when hixie's data
suggests that authors can't even be bothered to add longdesc content when
appropriate?  I thought the whole thrust of the WHAT WG's accessibility
strategy was that accessibility would 'just happen', without content
authors having to do more (which they already don't do). And if this
solution is so good, why use canvas at all?  Because it's 'cool'? I'd love
to see all this happen on a hand-held running Opera Mini, at a resolution
of, oh say, 120 pixels wide. [http://www.alistapart.com/articles/pocket/]


> >
> 
> This kind of thing seems to me a ridiculous level of complexity and a
> retrograde step in web development.
> 

Amen.

JF
Received on Thursday, 9 July 2009 23:55:54 UTC

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