RE: [1.2T LC]: accessing rules for traitAccess (ISSUE-2094 ACTION-2316)

Dear Andrew and all,
Thank you for your answer.  I'm not sure I understand your answer corecly:
You are saying that:
1) you think the restriction on the modification of the href while the element is in the tree is necessary and thus you will keep it ?
This address my comment and I am satisfied with it. I believe this is an important restriction.
2) You do not want to add additional restriction on the modification of xml:id (or id) of ellement already in the tree, because this is alleady implemented in most UA and in many content "in the wild", and you don't think this is a necessary restriction ?
This address my comment, and altrough I still think that if no restriction is imposed on xml:id then this will impose the same burden on implementation as if the href could be modified. I'm not happy with the answer but I understand and I am "satified" with it. 
Now, to re-send you erik's question:
what append when the xml:id of an element targeted by an animation is modified ?
- no effect the animation continue.
- an exception is raised 
- The animation stops (or start) on the new target (and stop on teh old target).
If there is no restriction on the modification of the xml:id of element in the tree and the target of an animation, then a note should be added to say that the result is not specified and will be UA dependent...


De: Andrew Emmons []
Date: ven. 24/10/2008 04:10
: Julien Reichel;
Objet : [1.2T LC]: accessing rules for traitAccess (ISSUE-2094 ACTION-2316)

Hello Julien,

Thank you very much for your question.

You are right in that allowing the modification of xml:id
does impart some burden on the UA with respect to handling the
change of animation elements. However, most implementation feedback
has been that there is still complexity in allowing any animation
element attribute to be modified while still within the tree. We feel
this complexity is enough to warrant the restriction, in order to reduce
implementation burden on small devices.

Please let us know shortly if this satisfies your comment.

All the best,
Andrew, On Behalf of the SVG WG

>In "Accessing rules for animation related elements" in the additional
>accessing rules for the trait access, it is specified that "[SMIL
>animation elements] cannot be modified using the TraitAccess methods
>once inserted into the tree". This means for instance that the "href"
>cannot be modified. I suppose that the purpose of this rule is to
>simplify the design of UA. However there are no rules that forbid to
>modify the xml:id of an element already inserted in the tree ( or did I
>miss it? ).

>Thus it is possible to modify the target of an animation by switching
>the xml:id of two elements (which is equivalent to a change of the href
>in the animation). So IMO this restriction  is insufficient to enable
>simplification of the UA design.  Note that modifying the xml:id of
>other even in the tree can also be used to modify the behavior of other
>attribute (like a begin="id1.begin" for instance)

>My question:

>- Why have such as restriction for the trait access (as there are other
>ways, not forbidden, to trigger the same effect) ?


Received on Friday, 24 October 2008 07:24:41 UTC