W3C home > Mailing lists > Public > public-aria@w3.org > March 2016

Re: Change to common definition of "hidden" in ARIA specs

From: Fred Esch <fesch@us.ibm.com>
Date: Thu, 3 Mar 2016 08:21:06 -0500
*1 Getting a definition that works for both HTML and SVG simplifies and
clarifies SVG accessibility :)

                                                              
     Regards,                                                 
                                                              
    Fred Esch                                                 
 Watson, IBM, W3C                                             
  Accessibility                                               
                                                              
 IBM Watson       Watson Release Management and Quality       
                                                              






From:	Amelia Bellamy-Royds <amelia.bellamy.royds@gmail.com>
To:	ARIA Working Group <public-aria@w3.org>, SVG-A11y TF
            <public-svg-a11y@w3.org>
Date:	03/02/2016 07:16 PM
Subject:	Change to common definition of "hidden" in ARIA specs



In SVG, it is possible for an element to be invisible (visibility: hidden)
but still interactive to click events (through the pointer-events style
property).  It is used, for example, to create an image-map behavior with a
raster image file, or to create large click regions for small data points
in a chart.

For the SVG accessibility mappings, we therefore want to make sure that
these interactive-but-invisible elements can be included in the
accessibility tree, so that assisstive technologies can forward events
correctly.  The current definition of "hidden" that is shared by all ARIA
specs (and which refers to elements that should be excluded from the
accessibility tree) doesn't factor this in.

Current definition:


Hidden
    Indicates that the element is not visible or perceivable to any user.
    An element is considered hidden if it or any one of its ancestor
    elements is not rendered or explicitly hidden.


Proposed definition:


Hidden
    Indicates that the element is not visible, perceivable, or
    interactive for any user. An element is considered hidden if it or any
    one of its ancestor elements is not rendered or is explicitly hidden.


The rest of the definition I think is flexible enough to work for both SVG
and HTML.  I've already proposed explicit definitions of "not rendered" in
SVG which is distinct from visibility.

~Amelia


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<html><body><p>*1 Getting a definition that works for both HTML and SVG simplifies and clarifies SVG accessibility :) <br><br><br>
<table border="0" cellspacing="0" cellpadding="0"><tr valign="top"><td width="473" colspan="2" valign="middle"><div align="center"><font size="4" face="Verdana">Regards, <br><br>Fred Esch <br>Watson, IBM, W3C Accessibility</font></div></td></tr>
<tr valign="top"><td width="130" valign="middle"><img src="cid:1__=0ABBF5F8DFDAB7828f9e8a93df938690918c0AB@" width="163" height="23" alt="IBM Watson" align="bottom"></td><td width="342" valign="middle"><font size="4" face="Verdana">Watson Release Management and Quality </font></td></tr></table><br><br><img width="16" height="16" src="cid:2__=0ABBF5F8DFDAB7828f9e8a93df938690918c0AB@" border="0" alt="Inactive hide details for Amelia Bellamy-Royds ---03/02/2016 07:16:25 PM---In SVG, it is possible for an element to be invisibl"><font color="#424282">Amelia Bellamy-Royds ---03/02/2016 07:16:25 PM---In SVG, it is possible for an element to be invisible (visibility: hidden) but still interactive to</font><br><br><font size="2" color="#5F5F5F">From:        </font><font size="2">Amelia Bellamy-Royds &lt;amelia.bellamy.royds@gmail.com&gt;</font><br><font size="2" color="#5F5F5F">To:        </font><font size="2">ARIA Working Group &lt;public-aria@w3.org&gt;, SVG-A11y TF &lt;public-svg-a11y@w3.org&gt;</font><br><font size="2" color="#5F5F5F">Date:        </font><font size="2">03/02/2016 07:16 PM</font><br><font size="2" color="#5F5F5F">Subject:        </font><font size="2">Change to common definition of &quot;hidden&quot; in ARIA specs</font><br><hr width="100%" size="2" align="left" noshade style="color:#8091A5; "><br><br><br><font size="4">In SVG, it is possible for an element to be invisible (visibility: hidden) but still interactive to click events (through the pointer-events style property).  It is used, for example, to create an image-map behavior with a raster image file, or to create large click regions for small data points in a chart.  </font><br><br><font size="4">For the SVG accessibility mappings, we therefore want to make sure that these interactive-but-invisible elements can be included in the accessibility tree, so that assisstive technologies can forward events correctly.  The current definition of &quot;hidden&quot; that is shared by all ARIA specs (and which refers to elements that should be excluded from the accessibility tree) doesn't factor this in.</font><br><br><font size="4">Current definition:</font><p><b><font size="4">Hidden</font></b><ul><font size="4">Indicates that the </font><a href="http://127.0.0.1:55557/svg-aam/svg-aam.html#dfn-element"><font size="4" color="#034575">element</font></a><font size="4"> is not visible or </font><a href="http://127.0.0.1:55557/svg-aam/svg-aam.html#dfn-perceivable"><font size="4" color="#034575">perceivable</font></a><font size="4"> to </font><i><font size="4">any</font></i><font size="4"> user. An element is considered </font><i><font size="4">hidden</font></i><font size="4"> if it or any one of its ancestor elements is not rendered or explicitly hidden.</font></ul><br><font size="4">Proposed definition:</font><p><b><font size="4">Hidden</font></b><ul><font size="4">Indicates that the element is not visible, perceivable, or interactive for </font><i><font size="4">any</font></i><font size="4"> user. An element is considered </font><i><font size="4">hidden</font></i><font size="4"> if it or any one of its ancestor elements is not rendered or is explicitly hidden.</font></ul><br><font size="4">The rest of the definition I think is flexible enough to work for both SVG and HTML.  I've already proposed explicit definitions of &quot;not rendered&quot; in SVG which is distinct from visibility.</font><br><br><font size="4">~Amelia</font><br><br><BR>
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Received on Thursday, 3 March 2016 14:13:48 UTC

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