W3C home > Mailing lists > Public > www-svg@w3.org > June 2009

Re: accessKey - label and alternative keys

From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Date: Wed, 17 Jun 2009 17:38:10 +0200
To: www-svg@w3.org
Message-Id: <200906171738.10224.Dr.O.Hoffmann@gmx.de>

There is no problem for authors to provide several methods to begin
and to end animations or the SVG tiny 1.2 animation element, for example:

<animation begin="accessKey(a)+2s; accessKey(1)+4s; 60s" ... />

Therefore I think, there is no need to modify the notation of an accessKey
begin.
Note that ';' is essential as a separator. This is already SMIL notation as
the accessKey notation too and should not be modified due to the 
complexity of declarative animation/timing and due to backwards 
compatibility and compatibility to SMIL.


To provide the meta information on how to begin and to end an 
animation or a timed element like video, audio, animation 
interactively is a general problem, because there is no generic 
mechanism to indicate this. Therefore a general help would be
required, not a specific solution for accessKey only ...

An author can in general note such meta information using 
the elements desc or metadata. If the user agent provides
the content of  title, desc, metadata (for example with a role
attribute or RDFa attribute like property to indicate the 
functionality of the information), the user can get informed.
The title element indeed is a bat choice for such information,
because it has another functionality of a title as a short
representation in an alternative text view - this should not
contain information about how to use something in general,
it contains information about what something is or
represents.



Typically in SVG 1.1 I use the element desc for this and 
other information to describe the functionality of an element
or to describe in general the complete document.

For example within SVG tiny 1.2 an author could note:

<circle r="10" xml:id="start" fill="blue" role="button" />
<circle cx="20" r="10" xml:id="stop" fill="red" role="button" />
<animation begin="start.activate; accessKey(a); accessKey(1); 60s"
end="stop.activate; accessKey(e); accessKey(0)"
dur="300s"  xlink:href="chainSawJuggler.svg" 
x="100" y="100" width="600" height="400"
initialVisibility = "always">
<metadata role="tooltip">Activate the animation with the blue
button, accessKey a or 1 or wait 60s until the animation starts automatically.
Stop the animation with the red buttion or with accessKey e or 0.</metadata>
</animation>

If an advanced viewer is able to interprete the role attribute, the
viewer can display the content of the metadata element as a tooltip.

Since desc contains more a general description, the author
just has to change the semantics of the sentence a little bit to
get a proper description, for example the desc of the
animation element could be:
'A chain saw juggler in action.
The juggling can be started either by activating the blue
button, using accessKey a or 1. Alternatively the juggler 
starts after one minute, because he gets bored.
The juggler either finishes after 5 minutes if not interrupted 
with the red button or with accessKey e or 0, just in case, 
it gets too exciting.'

Obviously it would be better to have a semantically more specific 
tooltip element for this functionality as already indicated in the old 
SVG 1.2 full draft to provide any kind of tooltip relevant for an 
element, but the available elements are already pretty helpful.

I cannot see the problem, why an author should not note
the begin and end conditions in a tooltip element, in desc or
metadata. 
If something more specific is required, one needs anyway 
indications about relations, which events or accessKeys are
related to which animation or timed elements.

Compared to 'HTML5' the advantage of SVG is, that it
already has several elements to contain some meta information
and several declarative methods to begin and to end timing 
due to interactivity, therefore the problems in SVG
are quite different than in 'HTML5'. In SVG mainly the 
interpretations of viewers of already existing accessibility 
features have to be improved, such that authors can really help 
users providing information with existing methods.
Maybe already such an indication like role="tooltip" will help,
if implemented.

Olaf
Received on Wednesday, 17 June 2009 15:48:31 GMT

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