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Can we please revert the removal of viewTarget attribute?

From: Amelia Bellamy-Royds <amelia.bellamy.royds@gmail.com>
Date: Thu, 29 Oct 2015 15:15:35 -0600
Message-ID: <CAFDDJ7ykv2YO=0EMW0yRnX8+6PqfyOMnaYtmzgL1Sn-cTTbRsg@mail.gmail.com>
To: www-svg <www-svg@w3.org>
Cc: SVG-A11y TF <public-svg-a11y@w3.org>, Cameron McCormack <cam@mcc.id.au>, Fred Esch <fesch@us.ibm.com>
Hello all,

Apologies for this being two months late, but I would like to STRONGLY
contest a resolution from the Paris F2F of August 2015, removing the
viewTarget attribute [1].

RESOLUTION: We will remove the <view viewTarget> attribute, its DOM
> property, and the corresponding view spec argument.

I'm sorry I did not notice this resolution at the time (resolutions, unlike
action items, don't trigger automatic emails).  Instead, Fred Esch of the
SVG Accessibility Task Force discovered it while doing final review of the
one of the SVG accessibility specs, and there was a dead link to SVG 2 for
the `viewTarget` attribute of <view> element.

So the first reason I would like to object is that this resolution was made
based on false pretenses.  The IRC log records:

> 13:35:14 [heycam]
> heycam: I wrote a quick test for viewTarget -- the attribute on <view> and
> the view spec argument
> 13:35:19 [heycam]
> http://mcc.id.au/temp/viewtarget.html
> 13:35:37 [heycam]
> heycam: nobody implements this

But Cam's test page seems to be testing a feature that never existed.
viewTarget was never supposed to change the view in and of itself.  A
viewBox was always required to do that.  The viewTarget attribute had two
purposes: one, purely semantic to identify the purpose of the view, and
two, to create a highlighting style on a particular element separate from
the change in view.

SVG 1 suggested that highlighting would be automatically applied by the
user agent (similar to focus outlines) [2], but no one implemented this and
it is aesthetically problematic.  SVG 1.1 suggested that the author could
define highlight styles using the :target selector [3], but there was no
clear conformance requirement that the CSS :target selector would match an
element targetted in this way (as opposed to an element directly specified
using a #id target fragment), and no one to my knowledge implemented it in
such a way.  I brought up this issue in February 2015, with the end result
being an Action on Cameron to follow up with the CSS WG to make sure there
was no problem with the SVG WG defining language-specific interpretations
of what :target meant [4].  (I'm not sure that ever happened...)

Regardless of whether anyone has or will implement a way for viewTarget to
trigger :target styles, however, there remains the very important semantic
information conveyed by viewTarget.  I was strongly relying on it in the
proposed spec for how to make <view> elements and changes of view
accessible to screen readers and other assistive technologies [5].

I would, at the very least, want to re-instate viewTarget for semantic and
accessibility purposes.  I would also ask that we follow up on the matter
of :target and viewTarget, which could have been a very useful added
functionality if it had ever been clearly defined.


[1]: http://www.w3.org/2015/08/26-svg-irc#T13-36-45
[2]: http://www.w3.org/TR/SVG10/linking.html#ViewElement
[3]: http://www.w3.org/TR/SVG11/linking.html#ViewHighlight
[4]: http://www.w3.org/2015/02/26-svg-minutes.html#item04
[5]: https://rawgit.com/w3c/aria/master/svg-aam/svg-aam.html#mapping_view
Received on Thursday, 29 October 2015 21:16:06 UTC

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