RE: review of SVG 2 animation-related requirements

Hi Brian,

Some comments inline.

> > 3. "Consider adding a 'key()' keyword for animation triggers"
> >
> http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Input#Consid
> e
> > r_adding_a_.27key.28.29.27_keyword_for_animation_triggers
> >
> > IIRC you were not in favour of this?
>
> I was a little hesitant about this.
>
> Part of the issue with supporting 'keydown()' etc. is modifier keys.
> Should they be used in SVG to provide consistent behaviour with HTML access
> keys? If so, does that limit the usefulness of, e.g.
> end="keydown(Enter)"? If not, are we introducing a potential security
> vulnerability through keylogging? Or can we say, "it's nothing you can't do
> already with script, just now you can do it with a different syntax"?
> Provided you disable accessKeys everywhere you disable script it should be safe
> to use without modifiers?
>
> Perhaps it's ok to accept it as a "nice to have" requirement. Assuming we can
> solve the modifier issue it's certainly preferably to try and match "Enter" than
> 0x0A or 0x0D.
SVG tiny 1.2 uses the AccessKey syntax to start animations, see http://www.w3.org/TR/SVGTiny12/animate.html#AccessKeyValueSyntax. I don't remember that there was any security concern, maybe we missed them. I'm not sure. Without scripting, how would you be able to log the keys and do something useful, just with AccessKey? The spec says that this behaves like a keydown listener so it could possibly be restricted similarly to scripting.

FWIW, GPAC implements a modified version of AccessKey, where the "character" is actually a DOM 3 Key Event (http://www.w3.org/TR/DOM-Level-3-Events/#key-values-list) and I found it useful in simple cases where script is not available.

>
> > 4. "The 'timelineBegin' attribute on the<svg>  element"
> >
> http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Input#the_.27
> > timelineBegin.27_attribute_on_the_.3Csvg.3E_element
>
> Yes. Although I think the requirement is not, "Add the timelineBegin attribute to
> SVG2", but "Provide a means for starting animations before the load event
> fires."
I agree.

>
> > 5. "The<discard>  element"
> >
> http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Input#the_.3C
> > discard.3E_element
>
> No.
The use case for the discard element was for long running animations to be able declaratively to remove some elements from the DOM when they were not needed anymore. I understand that this element can be problematic when mixed with scripts and when seeking, but it's really useful to keep the memory usage low (see http://biblio.telecom-paristech.fr/cgi-bin/download.cgi?id=7129). I've used it a lot in conversions of cartoon animations from Flash to SVG. I think it's a valid use case for SVG 2. How would you achieve that use case without?

Regards,
Cyril
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Received on Friday, 23 March 2012 03:43:24 UTC