Title: CSS Animations Module Level 2 Status: ED Work Status: Exploring Shortname: css-animations Level: 2 Group: csswg ED: https://drafts.csswg.org/css-animations-2/ TR: https://www.w3.org/TR/css-animations-2/ Previous Version: https://www.w3.org/TR/2023/WD-css-animations-2-20230602/ Editor: L. David Baron, Google https://www.google.com/, https://dbaron.org/, w3cid 15393 Editor: Brian Birtles, Invited Expert, brian@birchill.co.jp, w3cid 43194 !Issues List: https://github.com/w3c/csswg-drafts/labels/css-animations-2 Abstract: This CSS module describes a way for authors to animate the values of CSS properties over time, using keyframes. The behavior of these keyframe animations can be controlled by specifying their duration, number of repeats, and repeating behavior. Ignored Vars: auto-rewind
urlPrefix: https://dom.spec.whatwg.org/; type: dfn; spec: dom
text: event target
spec:cssom-1; type:dfn;
text:property name; for:CSS declaration
spec:web-animations-1; type:dfn;
text:active duration
text:active phase; for:animation effect
text:active time
text:after phase; for:animation effect
text:animation class
text:animation effect
text:animation playback events
text:associated effect
text:associated effect end
text:before phase; for:animation effect
text:current iteration
text:current time; for:animation
text:composite operation
text:fill mode
text:idle play state
text:idle phase; for:animation effect
text:iteration duration
text:iteration count
text:iteration start
text:keyframe
text:pause an animation
text:paused play state
text:pending pause task
text:pending play task
text:play an animation
text:play state
text:playback direction
text:start delay
text:target element
text:unresolved
spec:web-animations-2; type:dfn;
text:active interval; for:animation trigger
text:default range
text:exit range
spec:scroll-animations-1; type:dfn;
text:animation-range-start
text:animation-range-end
spec:css-animations-1; type:value;
text:running
text:paused
This is a delta specification, meaning that it currently contains only the differences from CSS Animations Level 1 [[!CSS3-ANIMATIONS]]. Once the Level 1 specification is closer to complete, it will be merged with the additions here into a complete level 2 specification.
# Animations # {#animations} Changes to any of the animation properties defined in this specification cause the corresponding {{CSSAnimation}} object and its associated objects to be updated according to the correspondence between these properties and Web Animations concepts defined in [[#keyframes]]. However, if the author modifies the animation using the Web Animations programming interface, the changes from the programming interface take precedence as follows: * After a successful call to {{KeyframeEffect/setKeyframes()}} on the {{KeyframeEffect}} associated with a {{CSSAnimation}}, any subsequent change to matching ''@keyframes'' rules or the resolved value of the 'animation-timing-function' property for the target element will not be reflected in that animation. However, if the last matching ''@keyframes'' rule is removed the animation must still be canceled. * After a successful call to {{AnimationEffect/updateTiming()}} on the {{KeyframeEffect}} associated with a {{CSSAnimation}}, for each property included in the {{AnimationEffect/updateTiming(timing)/timing}} parameter, any subsequent change to a corresponding animation property will not be reflected in that animation. For example, callingcssAnimation.effect.updateTiming({ duration: 1000 })
would cause subsequent changes to 'animation-duration' to be ignored
whilst changes to 'animation-delay' would still be reflected
in the {{KeyframeEffect}}'s timing.
* After a successful call to {{Animation/play()}} or {{Animation/pause()}}
on a {{CSSAnimation}},
any subsequent change to the 'animation-play-state' will no longer
cause the {{CSSAnimation}} to be played or paused
as defined in [[#animation-play-state]].
* After a successful call to {{Animation/reverse()}} on a {{CSSAnimation}}
or after successfully setting the {{Animation/startTime}}
on a {{CSSAnimation}},
if, as a result of that call the [=play state=] of the
{{CSSAnimation}} changes to or from the [=play state/paused=] play state,
any subsequent change to the 'animation-play-state' will no longer
cause the {{CSSAnimation}} to be played or paused
as defined in [[#animation-play-state]].
The requirement for a change to or from the [=play state/paused=] state
ensures that even after calling
{{Animation/reverse()}} or setting the {{Animation/startTime}}
on a running animation,
the animation continues to observe changes in 'animation-play-state'.
* After successfully setting the {{Animation/effect}} of a {{CSSAnimation}}
to null
or some {{AnimationEffect}} other than the original {{KeyframeEffect}},
all subsequent changes to animation properties other than
'animation-name', 'animation-play-state', or 'animation-timeline'
will not be reflected in that animation.
Similarly, any change to matching ''@keyframes'' rules will not be reflected
in that animation.
However, if the last matching ''@keyframes'' rule is removed
the animation must still be canceled.
Note, the reference to a successful call in the above rules
is necessary to ensure that
when an exception is thrown by any of these methods,
the override behavior is not applied.
## Owning element ## {#owning-element-section}
The owning element of an animation refers to the element or
pseudo-element to which the 'animation-name' property was applied that generated
the animation.
If the 'display' property of an element is set to ''display/none''
and its 'display' value would compute to ''display/none'' when ignoring the Transitions and Animations [=cascade origins=],
then terminate running animations with this owning element.
If an element has a 'display' of ''display/none'' and
its 'display' value had computed to ''display/none'' when ignoring the Transitions and Animations [=cascade origins=],
updating 'display' to a value other than ''display/none''
will start all animations applied to the element by the 'animation-name' property.
Note: In practice, this means that an animation to a 'display' value of ''display/none'' will not terminate running animations
unless the style also computes to ''display/none'' without the effect of the animations.
If an animation generated using the markup defined in this specification is
later disassociated from that markup by an update to the computed value of the
'animation-name' property on the owning element, the animation is
disassociated from its owning element (that is, it has no owning
element from that point forwards).
animation's initial owning element
is elem. animation is disassociated from
element through an update to the computed value of
elem's 'animation-name' property.
elem.style.animation = 'spin 1s'; let animation = elem.getAnimations()[0]; // animation's owning element is elem elem.style.animation = ""; // animation no longer has an owning elementNote that although the owning element is often equal to the [=target element=] of an animation's [=associated effect=], this is not always the case. The following example demonstrates some of the situations where these two elements may differ.
elem.style.animation = 'move 1s'; let animation = elem.getAnimations()[0]; // animation.effect.target == elem == animation's owning element animation.effect.target = elem2; // animation.effect.target == elem2 != animation's owning element animation.effect = null; // animation.effect?.target is undefined != animation's owning element
Name: animation-duration Value: [ auto | <The 'animation-duration' property specifies the [=iteration duration=] of the animation's associated [=animation effect=].
Name: animation-composition Value: <<single-animation-composition> = replace | add | accumulate The values of 'animation-composition' have the meaning defined for the corresponding values of the composite operation defined in Web Animations [[!WEB-ANIMATIONS]]. When specified in a keyframe, 'animation-composition' defines the composite operation to use for each property specified in that keyframe until the next keyframe specifying each property.># Initial: replace Applies to: all elements Inherited: no Percentages: N/A Computed value: list, each item a keyword as specified Animation type: not animatable Canonical order: per grammar
@keyframes heartbeat {
from {
scale: 1;
animation-timing-function: ease-out;
}
30% {
scale: 1.3;
}
}
.heartbeat {
animation: heartbeat 0.3s 2s infinite;
}
@keyframes throb {
50% {
scale: 1.8;
}
}
.icon:mouseover {
animation: throb 0.4s add;
}
If these two animations are applied to the same element, normally only
one animation would apply, but by specifying ''add'' as the
'animation-composition' on the second animation, the result of the two
animations will be combined.
Since CSS Transitions [[CSS3-TRANSITIONS]] have a lower composite
order, it is possible to use 'animation-composition' to combine CSS
Animations with underlying transitions as in the following example.
.icon {
filter: blur(20px);
transition: filter 0.5s;
}
.icon:hover {
filter: blur(0px);
animation: brightness-pulse 3s infinite add;
}
@keyframes brightness-pulse {
0% {
scale: 1.1;
filter: brightness(130%);
}
10% {
scale: 1;
filter: brightness(100%);
}
}
Issue: Create pictures of these examples and verify they make sense.
Name: animation-timeline Value: <># Initial: auto Applies to: all elements Inherited: no Percentages: N/A Computed value: list, each item either the keyword ''single-animation-timeline/none'', the keyword ''single-animation-timeline/auto'', a case-sensitive [=css identifier=], a computed ''scroll()'' function, or a computed ''view()'' function Canonical order: per grammar Animation Type: not animatable