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animate-elem-39-t timing issue

From: Cameron McCormack <cam@mcc.id.au>
Date: Wed, 22 Dec 2010 14:12:13 +1300
To: public-svg-wg@w3.org
Message-ID: <20101222011212.GD11105@wok.mcc.id.au>
I think animate-elem-39-t also suffers from a timing issue wrt
non-interpolable values.  The <animate> that targets the <a
xlink:href=“> is currently:

  <a xlink:href="animate-elem-09-t.svg">
    <animate attributeName="xlink:href"
      from="animate-elem-09-t.svg" to="animate-elem-03-t.svg"
      begin="1s;showAnchor2.end+1s" dur="1s"/>

According to spec, an animation with calcMode="linear" will be treated
as calcMode="discrete" if the attribute is of a type that doesn’t have
values that can be interpolated.  A discrete from-to animation will show
the from value for the first half of the simple duration and the to
value for the second half.  Thus the link target is changed to
"animate-elem-03-t.svg" for a quarter of the time the document is

  0s     0.5s   1s     1.5s   2s     2.5s


  “-” means the animation isn’t applied and the underlying value of
      the attribute is used ("animate-elem-09-t.svg")
  “F” means the animation is applied, and is applying the from value
      (also "animate-elem-09-t.svg")
  “T” means the animation is applied, and is applying the to value

This doesn’t match up with the changes to the actual text being
displayed (the “09” or “03”).

What we instead want is either:

  0s     0.5s   1s     1.5s   2s     2.5s


  0s     0.5s   1s     1.5s   2s     2.5s

I propose that we change this animation to be like some of the others in
the document:

  <animate attributeName="xlink:href"
    from="animate-elem-09-t.svg" to="animate-elem-03-t.svg"
    begin="0s;showAnchor2.end" dur="2s"/>

Let me know if you agree (anyone).  I will make this change unless there
are any objections.

Cameron McCormack ≝ http://mcc.id.au/
Received on Wednesday, 22 December 2010 01:12:51 UTC

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