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Re: CSS animation perf statistics

From: Robert O'Callahan <robert@ocallahan.org>
Date: Fri, 8 Jul 2011 15:18:43 +1200
Message-ID: <CAOp6jLYPAmwowWSmRH8T6gb38rCkBAGqGKAgqsYL0tsemjMNBg@mail.gmail.com>
To: Sigbjørn Vik <sigbjorn@opera.com>
Cc: public-web-perf@w3.org, Andrew Dupont <w3@andrewdupont.net>
On Thu, Jun 16, 2011 at 1:12 AM, Sigbjørn Vik <sigbjorn@opera.com> wrote:

> Opera experimented with some related technology some time ago, see
> http://dev.opera.com/articles/view/presto-2-2-and-opera-10-a-first-look/#fps.
> Those demos still work in Opera 11.
>
> That gave the developer currentFPS and targetFPS properties to play with. A
> similar setup could be included in e.g. CSS, imagine the following:
>
> @media (min-fps:30) {
>        body { transition-property: opacity; transition-duration: 2s; }
> }
>
> Of course, a currentFPS property could additionally be added to the
> RequestAnimationFrame specification.
>

An "FPS" media query value sounds like a great idea if we could implement
it, but there are some pretty serious hysteresis issues. How would you
implement this? Try running the page with nominal FPS of 60, discover that
you're only getting 20 FPS, disable the @media rule, discover you're now
getting 40 FPS, then what?

My main worry is that you can only really discover whether or not you can
play the animation by actually trying to play it. But starting to play it,
then suddenly turning it off, is likely to not be acceptable.

Rob
-- 
"If we claim to be without sin, we deceive ourselves and the truth is not in
us. If we confess our sins, he is faithful and just and will forgive us our
sins and purify us from all unrighteousness. If we claim we have not sinned,
we make him out to be a liar and his word is not in us." [1 John 1:8-10]
Received on Friday, 8 July 2011 03:19:10 UTC

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