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RE: SVG12: event base for audio/video/animation elements

From: Doug Schepers <doug.schepers@vectoreal.com>
Date: Thu, 6 Jul 2006 01:54:04 -0400
To: "'Bjoern Hoehrmann'" <derhoermi@gmx.net>
Cc: <www-svg@w3.org>
Message-Id: <20060706055407.CE2285780@postalmail-a3.dreamhost.com>

Hi, Bjoern-

Bjoern Hoehrmann wrote:
| 
| * Doug Schepers wrote:
| >From our reading of the SMIL Timing Events specification, the default
| >event-base for geometrically-rendered elements is the 
| element itself, and
| >for non-graphical elements, such as audio, it is the SVG 
| root itself, as a
| >consequence of event bubbling.
| 
| I am not aware of a "SMIL Timing Events" specification, and from the
| name it seems rather irrelevant as this has nothing to do with SMIL-
| defined event types. In any case,

I'm referring to the SMIL 2.0 Timing and Synchronization Module [1], wherein
it says:

"Event values

This section is informative

An Event value starts with an Eventbase-element term that specifies the
event-base element. The event-base element is the element on which the event
is observed. Given DOM event bubbling, the event-base element may be either
the element that raised the event, or it may be an ancestor element on which
the bubbled event can be observed."

and, normatively:

"The eventbase-element must be another element contained in the host
document.

If the Eventbase-element term is missing, the event-base element defaults to
the element on which the eventbase timing is specified (the current
element)."

The first normative sentence indicates that the event-base (if and only if
it is not the element itself) must be in the same document, while the second
sentence indicates that an unspecified event-base is the element itself.


| >We have contacted the SYMM WG to confirm that this is the 
| case.  If they
| >indicate otherwise, we will make this explicit in our specification.
| 
| that is certainly not acceptable, as even if what you say is true,
| which is very unlikely (SMIL doesn't know about "SVG root", SMIL
| never specifies the event base as the document element, this has
| nothing to do with event bubbling, ...), as my concern is that it
| is not clear from the draft or its normative references (you are
| not able to point out where SMIL specifies this, you have to ask
| the SYMM WG; that might work for you, but does not work for me).

>From the quotations above, we inferred that the default event-base for
rendered elements is the element itself.

For non-graphical elements, such as 'audio', which cannot receive events
directly, it is the element's ancestor (the root) that is the event-base.
This is from the statement, "Given DOM event bubbling, the event-base
element may be either the element that raised the event, or it may be an
ancestor element on which the bubbled event can be observed." 

As I said, we have sent a request for confirmation of this interpretation,
or further clarification, to the SYMM Working Group, since this does seem to
be open to interpretation.  If you have further insight or a strong opinion
on this, however, we would be happy to consider it for inclusion in the SVG
Tiny 1.2 spec.

 
[1]
http://www.w3.org/TR/2005/REC-SMIL2-20050107/smil-timing.html#Timing-EventVa
lueSyntax

Regards-
Doug
Received on Thursday, 6 July 2006 05:54:14 GMT

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