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