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Re: [css3-animations] Effect of display:none and visibility:hidden on animations

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 20 Jul 2011 07:48:18 -0700
Message-ID: <CAAWBYDCwxBs76u=_h5hf5PK8xLizfJRgBk745nD9fCzwdnJqmA@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: Sylvain Galineau <sylvaing@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
On Tue, Jul 19, 2011 at 9:34 PM, Rik Cabanier <cabanier@gmail.com> wrote:
> The biggest advantage would be performance since the CSS is interpreted
> directly by native code in the browser.

There would be no performance difference; the JS API, being designed
into the browser, would hook into the same mechanics that CSS
animations do.  I'm not talking about doing JS-based animations where
you fire some callback every delta of time and adjust a value a little
bit manually; I'm talking about creating or retrieving Animation
objects in JS (which are backed by the same data structures created by
CSS animations) and then manipulating them.


> Another advantage is editability. Users and design applications would be
> able to read the animation CSS back in and modify it. This would be
> impossible if animation is done through JS.
> For instance animations that are generated by swiffy or smokescreen can not
> be read in by any other programs.

That's because they're doing the animations manually.  There isn't
actually an animation there, just a bunch of code that's run
regularly.

If you use actual Animation objects, you can potentially query them
from other tools.


> Why is it not worthwhile?
> Do you believe that the browser implementation will get too complex?

Yes.  I believe that the range of things that authors want to do with
regards to timing and synchronizing animations is too wide to be
easily done in a declarative syntax, particularly one that still looks
like CSS.

> The current spec is only good for very simple content. I believe that it
> will be much more powerful with a couple of small changes.

I don't disagree.  What I disagree with is the assertion that we'll
only want "a couple" of changes.

~TJ
Received on Wednesday, 20 July 2011 14:49:12 GMT

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