W3C home > Mailing lists > Public > www-style@w3.org > January 2010

[animations] stepped timing function proposal

From: Dean Jackson <dino@grorg.org>
Date: Wed, 20 Jan 2010 09:50:07 +1100
Message-Id: <3FBAC8E5-981E-41B2-B5D8-4880032184B3@grorg.org>
To: "www-style@w3.org list" <www-style@w3.org>
I propose a new value for the "animation-timing-function" property, allowing a value to jump instantly from one keyframe to another, rather than be interpolated.

A good example of why this is useful is the progress spinner on OSX which could be implemented as an infinite rotation. Also, this feature is in SMIL/SVG [1] as calcMode="discrete". However, I think we should consider going one step beyond what SMIL suggested and allow the step to happen either at the beginning or end of the keyframe.

jump-start
  There is no interpolation. The property instantly changes to the end value as soon as the animation begins.

jump-end
  There is no interpolation. The property remains at its start value until the animation ends, at which point it instantly changes to the end value.

Feel free to suggest better names: "discrete", "step", whatever.

This timing function should also be allowed in transitions.

[1] http://www.w3.org/TR/SVG/animate.html#ValueAttributes
Received on Tuesday, 19 January 2010 22:50:51 GMT

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