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Re: [css3-animation] keyframes and percentages

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 10 Oct 2012 10:21:07 -0700
Message-ID: <CAAWBYDAsoYe_=kxb+cjx6vgHCt7D_pRBV8tLANFfnLrSjHrDLw@mail.gmail.com>
To: Simon Fraser <smfr@me.com>
Cc: Øyvind Stenhaug <oyvinds@opera.com>, Glenn Adams <glenn@skynav.com>, www-style@w3.org
On Wed, Oct 10, 2012 at 10:14 AM, Simon Fraser <smfr@me.com> wrote:
> On Oct 10, 2012, at 5:21 am, Øyvind Stenhaug <oyvinds@opera.com> wrote:
>> On Wed, 10 Oct 2012 04:20:59 +0200, Glenn Adams <glenn@skynav.com> wrote:
>>> keep in mind that
>>>
>>> -20%, 20% { top: 10px; animation-timing-function: ease-out; }
>>>
>>> should not ignore the 20% keyframe, but ignore the -20% keyframe
>>
>> I dont' think this follows from the current editor's draft, or at the very least it's not at all clear.
>> "The keyframe selector for a keyframe style rule consists of a comma-separated list of percentage values or the keywords ‘from’ or ‘to’"
>> "If a keyframe selector specifies negative percentage values or values higher than 100%, then the keyframe will be ignored."
>> I read that as saying that if the comma-separated list contains negative percentage values or values >100%, the entire rule (selector + block) is ignored. I suppose it's possible to read it differently.
>
> You're right in that what people want isn't covered by the draft, and I'm not sure how it should be worded to fix that.
>
> One option would be to describe an algorithm that separates out keyframes with comma-separated keyframe selectors into individual keyframes with simple selectors before applying the "ignore negative values" rule.

Separate out the concept of a "keyframe rule" from a "keyframe".  The
former is a syntactic construct, the latter is a meaningful concept in
the animation model.  A single keyframe rule can define multiple
keyframes.  Done.  ^_^

~TJ
Received on Wednesday, 10 October 2012 17:21:54 GMT

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