W3C home > Mailing lists > Public > www-svg@w3.org > March 2011

Re: Proposal: Fix discrete to animation in SVG 1.1 Second Edition

From: Cameron McCormack <cam@mcc.id.au>
Date: Wed, 30 Mar 2011 09:37:55 +1300
To: "Dr. Olaf Hoffmann" <Dr.O.Hoffmann@gmx.de>
Cc: www-svg@w3.org
Message-ID: <20110329203754.GA15189@wok.mcc.id.au>
Dr. Olaf Hoffmann:
> Are there already ideas how to indicate an SVG 1.1 second edition
> document, for example version="1.1.2" or something like this?

No, there won’t be a new value for that attribute.

> This becomes more and more important, if the number of incompatible
> changes of definitions in the second edition increases even more ...
> Else having two definitions for one feature effectively results
> in an undefined feature again, that authors should never use (and
> implementors not implement) ...

The idea is that implementations will transition to having the new
behaviour.  There will of course be a time during which some popular
implementations follow the First Edition’s requirements and some follow
the Second Edition’s.  Specifying version="1.1.2" doesn’t actually help
work around that; implementations will not look at the attribute and
switch behaviour.

We (the Working Group), when making incompatible changes, judge that the
change’s importance outweighs breaking existing content.  If it is a
major feature that a lot of existing content uses, then that will argue
against making the change in the first place.  If it is an edge case or
something that is not used by much content, then it makes it easier to
change.  If we want to correct past mistakes/bugs in SVG, then we have
to make such tradeoffs.

In this particular instance (discrete to-animation), the specification
change would align with implementations.  That should result in less
content breakage than if we kept the specification as is and convinced
implementors to fix the bug.

> It is a difference to fix bugs in the second edition or to
> define things, that are undefined in the first edition or to fix
> contradictions in the first edition compared to a situation with a
> change of a defined behaviour.

You could say that if we define behaviour that was previously undefined
or ambiguous, then content should not have been relying on it in the
first place.  The consequences are the same, though: as implementations
change to follow the rules in Second Edition, content that relied on the
undefined behaviour going a different way will break.  The same
judgments need to be made to decide whether to specify one way or the
other.

-- 
Cameron McCormack ≝ http://mcc.id.au/
Received on Tuesday, 29 March 2011 20:38:35 GMT

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