[web-animations] computedTiming.iterationStart and fill attributes

[Сергей Грехов]

Hi All,

It's unclear from the spec what values should return
computedTiming.iterationStart and fill attributes for some values.
Example:

var timing = {
iterationStart: -100,
duration: 1000
};
var animation = new Animation(target, [], timing);
var player = document.timeline.play(animation);

animation.computedTiming.iterationStart == ? // -100 or 0?
animation.computedTiming.fill == ? // 'auto' or 'none'?

Specification only reads that these attributes of computed timing return
fill mode and iteration start properties of animation node. For timing
calculations
(http://w3c.github.io/web-animations/#dom-animationtiming-iterationstart)
Values less than zero are clamped to zero for the purpose of timing model
calculations. and
(http://w3c.github.io/web-animations/#dom-animationtimingreadonly-fill)
When performing timing calculations the special value auto is expanded to
one of the fill modes recognized by the timing model...

But what shoul be returned by computedTiming? Original value or the one
that used for timing calculations?

--
Sergey G. Grekhov

[web-animations] Some specification issues

[Сергей Грехов]

A couple of specification issues.

1) WebIDL for KeyframeEffect
(http://w3c.github.io/web-animations/#the-keyframeeffect-interfaces)
contains the following

// Mutable additions to KeyframeEffectReadonly interface
inherit attribute DOMString spacing;
voidsetFrames (object frames);

I think that spacing attribute is not an addition to
KeyframeEffectReadonly interface but rather mutable override of its member

2) KeyframeEffectReadonly.clone() returns KeyframeEffect instance. It
should return KeyframeEffectReadonly instance. Otherwise this method
should be moved to KeyframeEffect interface

3) Definition of AnimationTimingReadonly.fill attribute
(http://w3c.github.io/web-animations/#dom-animationtimingreadonly-fill) is
the following:

- If the animation node to which the fill mode is being is applied is an
animation,
Use none as the fill mode.
- Otherwise,
Use both as the fill mode.

On level 1 we define only one type of animation node - animation. Does it
makes sense describe fill behavior for non animation nodes here?

Thank you,
Sergey G. Grekhov