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Re: Should the base svg tag receive events?

From: Doug Schepers <schepers@w3.org>
Date: Wed, 25 Aug 2010 13:43:59 -0400
Message-ID: <4C75565F.3000105@w3.org>
To: Domenico Strazzullo <nst@dotuscomus.com>
CC: Kevin Ar18 <kevinar18@hotmail.com>, www-svg@w3.org
Hi, Nico-

Domenico Strazzullo wrote (on 8/25/10 6:36 AM):
>
> The original post is always available in the archives.
>
>> Why the svg element should NEVER "dispatch" an event due to user
>> interaction:
>
> You cite parts of the svg spec as sustaining evidence. The validity itself
> of the spec in regard to pointer events is in cause. The spec cannot be
> used as evidence for argumentation.

Actually, it can and should.  There are many details in any technical 
specification where we pick an arbitrary behavior, which implementers 
should follow for the sake of interoperability.

An example that springs to mind: what is the starting point of a 
rectangle or circle?  This matters because a stroke-dasharray will look 
different on different viewers otherwise, which is not usually what the 
content author wants.

Some issues are less arbitrary, and there are good reasons for any of 
several specific behaviors; in that case, we simply have to pick one, 
based on the best evidence, and require implementations to exhibit that 
behavior.

When there are conflicts between specifications, that does cause a 
problem; however, don't assume that the first specification got it 
right.  For example, HTML5 deliberately contradicts several other 
(non-HTML) specifications, because the implications of the behavior they 
describe is suboptimal in the HTML context, and the group and editor of 
HTML5 made the conscious choice to change the behavior.  In the best 
cases, this results in a fix to the original spec, through consensus... 
specs are never perfect, and they can change over time.

The SVG spec has changed in the past based on implementation realities; 
this may be an instance where it changes again.  We don't know yet.


> Essentially you say "The spec is right because it says so",

In most cases, I think that this argument is perfectly reasonable.  The 
spec says what it does because it was the end point of a line of 
reasoning that the working group responsible for the spec had consensus on.


> where we are contesting the very legitimacy of what it  says,
> as well as the self-attribution of the prerogative of overriding
> other specifications.

As the editor for the DOM3 Events specification, I feel pretty confident 
that the SVG 1.1 spec is not contradicting or overriding that spec on 
this issue.  I don't agree with Boris' assessment that SVG 1.1 is 
self-contradictory here; I think that there is an interpretation of the 
spec that is perfectly consistent with itself and with other specs.

All that said, we may change the spec anyway, to match some 
implementations.  Or we (where we includes the implementers) may ask the 
implementations to change.  That's where we stand with the issue.  We'll 
decide it at the next SVG WG F2F in a week or two.

Regards-
-Doug Schepers
W3C Team Contact, SVG and WebApps WGs
Received on Wednesday, 25 August 2010 17:44:03 GMT

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