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acazsouza

Why jQuery uses 77 fps by default in animation?

in Developing jQuery Core • 1 year ago

Hi, I questioned a developer of mootools, and he said the mootools use by default 20 fps in animations.

He send me this link: How many frames per second can the human eye see? http://www.100fps.com/how_many_frames_can_humans_see.htm

He said that animations that use more than 25 fps is an unnecessary processing.

Mootools animation is sometimes more smooth than jquery for making use of less processing?

Why jquery use 1000 / 13 = ~77 fps by default??

Replies(8)

acazsouza

Re: Why jQuery uses 77 fps by default in animation?

1 year ago

Someone?!

Re: Why jQuery uses 77 fps by default in animation?

1 year ago

Whatever the reason for originally setting the rate that high, it is now configurable in 1.4.3 so you can change the value yourself.

http://api.jquery.com/jQuery.fx.interval/

If you're inclined to do so, perhaps you could create some tests to show the impact of changing the interval value? We might change the default in 1.5 but we'd need some test cases.

acazsouza

Re: Why jQuery uses 77 fps by default in animation?

1 year ago

I know I can change this value now.

I wanted to find out WHY he was chosen 1000 / 13 = ~ 77 fps by default?

Re: Why jQuery uses 77 fps by default in animation?

1 year ago

Having a fixed FPS doesn't take into account the differing processing power of different devices, the way some browsers render the page using hardware acceleration (or not), the way in which available processing resource varies over time, and plenty of other variables which will ultimately determine the maximum FPS that could potentially be delivered for a given animation at a given moment in a given browser in a given device.

Ideally the FPS should vary dynamically and only be *capped* at a threshold above which a higher FPS would be of no perceivable value - AFAIK this is how CSS3 animations work in browsers that support it, but alas I don't think it's (currently) possible to do this kind of dynamic animation throttling in JS, which is why jQuery takes the rather basic fixed FPS approach.

However, I have recently discovered an excellent jQuery plugin which stealthily upgrades certain .animate() calls to use CSS3 animations where possible, and the difference in animation smoothness can be quite impressive - see http://playground.benbarnett.net/jquery-animate-enhanced/

acazsouza