From 05d6263e65d8cae4fa782e743ff032677d8497ac Mon Sep 17 00:00:00 2001 From: fantasai Date: Tue, 22 Aug 2023 12:51:49 -0400 Subject: [PATCH] [web-animations-1] Define 'start time' for animation effects See https://github.com/w3c/csswg-drafts/pull/8985#discussion_r1300440338 --- web-animations-1/Overview.bs | 116 ++++++++++++++++++----------------- 1 file changed, 59 insertions(+), 57 deletions(-) diff --git a/web-animations-1/Overview.bs b/web-animations-1/Overview.bs index 375b5929327c..ddd915a2f8e3 100644 --- a/web-animations-1/Overview.bs +++ b/web-animations-1/Overview.bs @@ -449,7 +449,7 @@ Specification conventions {#spec-conventions} Where this specification does not specifically link to a procedure, text that requires the user agent to update a property, - such as “make |animation|'s [=start time=] [=unresolved=]”, + such as “make |animation|'s [=animation/start time=] [=unresolved=]”, should be understood to refer to updating the property directly without invoking any related procedure. @@ -906,7 +906,7 @@ Animations {#animations} : If any of the following are true: * the animation has no associated [=timeline=], or * the associated [=timeline=] is [=inactive timeline|inactive=], or - * the animation's [=start time=] is [=unresolved=], + * the animation's [=animation/start time=] is [=unresolved=], :: The [=animation/current time=] is an [=unresolved=] time value. @@ -942,7 +942,7 @@ Animations {#animations} 1. Let the [=timeline=] of |animation| be |new timeline|. - 1. If the [=start time=] of |animation| is [=unresolved|resolved=], + 1. If the [=animation/start time=] of |animation| is [=unresolved|resolved=], make |animation|'s [=hold time=] [=unresolved=]. Note: This step ensures that the [=finished play state=] of |animation| @@ -1014,14 +1014,14 @@ Setting the associated effect of an animation 1. Abort these steps. 2. Update either |animation|'s [=hold time=] or - [=start time=] as follows: + [=animation/start time=] as follows:
: If any of the following conditions are true: * |animation|'s [=hold time=] is [=unresolved|resolved=], or - * |animation|'s [=start time=] + * |animation|'s [=animation/start time=] is [=unresolved|unresolved=], or * |animation| has no associated [=timeline=] or the associated [=timeline=] is @@ -1032,7 +1032,7 @@ Setting the associated effect of an animation : Otherwise, :: - Set |animation|'s [=start time=] to the result of evaluating + Set |animation|'s [=animation/start time=] to the result of evaluating timeline time − (seek time / playback rate) where |timeline time| is the current [=time value=] of the [=timeline=] associated with |animation|. @@ -1041,11 +1041,11 @@ Setting the associated effect of an animation 1. If |animation| has no associated [=timeline=] or the associated [=timeline=] is [=inactive timeline|inactive=], - make |animation|'s [=start time=] [=unresolved=]. + make |animation|'s [=animation/start time=] [=unresolved=]. Note: This preserves the invariant that when we don't have an active timeline - it is only possible to set either the [=start time=] + it is only possible to set either the [=animation/start time=] or the animation's [=animation/current time=]. 1. Make |animation|'s [=previous current time=] [=unresolved=]. @@ -1063,7 +1063,7 @@ Setting the associated effect of an animation by performing the following steps: 1. Set |animation|'s [=hold time=] to |seek time|. 1. [=Apply any pending playback rate=] to |animation|. - 1. Make |animation|'s [=start time=] [=unresolved=]. + 1. Make |animation|'s [=animation/start time=] [=unresolved=]. 1. Cancel the [=pending pause task=]. 1. [=resolve a Promise|Resolve=] |animation|'s [=current ready promise=] @@ -1094,8 +1094,9 @@ Setting the associated effect of an animation Note: This preserves the invariant that when we don't have an active timeline - it is only possible to set either the [=start time=] - or the animation's [=animation/current time=]. + it is only possible to set either + the [=animation=]’s [=animation/start time=] + or its [=animation/current time=]. 1. Let |previous current time| be |animation|'s [=animation/current time=]. @@ -1106,7 +1107,7 @@ Setting the associated effect of an animation 1. [=Apply any pending playback rate=] on |animation|. - 1. Set |animation|'s [=start time=] to |new start time|. + 1. Set |animation|'s [=animation/start time=] to |new start time|. 1. Update |animation|'s [=hold time=] based on the first matching condition from the following: @@ -1157,10 +1158,10 @@ Waiting for the associated effect To avoid this problem, Web Animations typically begins timing animations from the moment when the first frame of the animation is complete. - This is represented by an [=unresolved=] [=start time=] on the [=animation=] + This is represented by an [=unresolved=] [=animation/start time=] on the [=animation=] which becomes resolved when the animation is [=ready=]. Content can opt out of this behavior by setting - the [=start time=] to a [=unresolved|resolved=] [=time value=]. + the [=animation/start time=] to a [=unresolved|resolved=] [=time value=]. @@ -1268,7 +1269,7 @@ Waiting for the associated effect 1. If the following three conditions are all satisfied: * |seek time| is [=unresolved=], and - * |animation|'s [=start time=] is [=unresolved=], and + * |animation|'s [=animation/start time=] is [=unresolved=], and * |animation|'s [=animation/current time=] is [=unresolved=], set |seek time| to zero. @@ -1285,7 +1286,7 @@ Waiting for the associated effect : If |has finite timeline| is true, :: - 1. Set |animation|'s [=start time=] to |seek time|. + 1. Set |animation|'s [=animation/start time=] to |seek time|. 1. Let |animation|'s [=hold time=] be [=unresolved=]. 1. [=Apply any pending playback rate=] on |animation|. @@ -1296,7 +1297,7 @@ Waiting for the associated effect 1. If |animation|'s [=hold time=] is [=unresolved|resolved=], - let its [=start time=] be [=unresolved=]. + let its [=animation/start time=] be [=unresolved=]. 1. If |animation| has a [=pending play task=] or a [=pending pause task=], @@ -1319,7 +1320,7 @@ Waiting for the associated effect 1. Schedule a task to run as soon as |animation| is [=ready=]. The task shall perform the following steps: - 1. Assert that at least one of |animation|'s [=start time=] or [=hold time=] + 1. Assert that at least one of |animation|'s [=animation/start time=] or [=hold time=] is [=unresolved|resolved=]. 1. Let |ready time| be the [=time value=] of @@ -1342,12 +1343,12 @@ Waiting for the associated effect If the [=playback rate=] is zero, let |new start time| be simply |ready time|. - 1. Set the [=start time=] of |animation| to |new start time|. + 1. Set the [=animation/start time=] of |animation| to |new start time|. 1. If |animation|'s [=playback rate=] is not 0, make |animation|'s [=hold time=] [=unresolved=]. - : If |animation|'s [=start time=] is resolved + : If |animation|'s [=animation/start time=] is resolved and |animation| has a [=pending playback rate=], :: @@ -1368,7 +1369,7 @@ Waiting for the associated effect If the [=playback rate=] is zero, let |new start time| be simply |ready time|. - 1. Set the [=start time=] of |animation| to |new start time|. + 1. Set the [=animation/start time=] of |animation| to |new start time|. @@ -1427,7 +1428,7 @@ Waiting for the associated effect ### Pausing an animation ### {#pausing-an-animation-section} - Whenever an [=animation=] has an [=unresolved=] [=start time=], + Whenever an [=animation=] has an [=unresolved=] [=animation/start time=], its [=animation/current time=] will be suspended. As with [=play an animation|playing an animation=], @@ -1483,11 +1484,11 @@ Waiting for the associated effect : If |has finite timeline| is true, :: - Set |animation|'s [=start time=] to |seek time|. + Set |animation|'s [=animation/start time=] to |seek time|. : Otherwise, :: - Set |animation|'s [=hold time=] to |seek time|. + Set |animation|'s [=animation/hold time=] to |seek time|. @@ -1517,7 +1518,7 @@ Waiting for the associated effect at the moment when the user agent completed processing necessary to suspend playback of |animation|'s [=associated effect=]. - 1. If |animation|'s [=start time=] is [=unresolved|resolved=] + 1. If |animation|'s [=animation/start time=] is [=unresolved|resolved=] and its [=hold time=] is not resolved, let |animation|'s [=hold time=] be the result of evaluating (ready time − start time) @@ -1531,7 +1532,7 @@ Waiting for the associated effect 1. [=Apply any pending playback rate=] on |animation|. - 1. Make |animation|'s [=start time=] unresolved. + 1. Make |animation|'s [=animation/start time=] unresolved. 1. [=resolve a Promise|Resolve=] |animation|'s [=current ready promise=] with |animation|. @@ -1638,7 +1639,7 @@ Waiting for the associated effect until it reaches zero. A running animation that has reached this boundary (or overshot it) - and has a [=unresolved|resolved=] [=start time=] + and has a [=unresolved|resolved=] [=animation/start time=] is said to be [=play state/finished=]. The crossing of this boundary @@ -1690,7 +1691,7 @@ Waiting for the associated effect * the |unconstrained current time| is [=unresolved|resolved=], and - * |animation|'s [=start time=] is [=unresolved|resolved=], + * |animation|'s [=animation/start time=] is [=unresolved|resolved=], and * |animation| does not have a [=pending play task=] or a [=pending pause task=], @@ -1732,7 +1733,7 @@ Waiting for the associated effect 1. If |did seek| is true and the [=hold time=] is [=unresolved|resolved=], - let |animation|'s [=start time=] be equal to + let |animation|'s [=animation/start time=] be equal to the result of evaluating timeline time − (hold time / playback rate) @@ -1893,16 +1894,16 @@ Waiting for the associated effect 1. [=Silently set the current time=] to |limit|. - 1. If |animation|'s [=start time=] is [=unresolved=] + 1. If |animation|'s [=animation/start time=] is [=unresolved=] and |animation| has an associated [=active timeline=], - let the [=start time=] be the result of evaluating + let the [=animation/start time=] be the result of evaluating timeline time − (limit / playback rate) where |timeline time| is the current [=time value=] of the associated [=timeline=]. 1. If there is a [=pending pause task=] - and [=start time=] is [=unresolved|resolved=], + and [=animation/ time=] is [=unresolved|resolved=], 1. Let the [=hold time=] be [=unresolved=]. @@ -1916,7 +1917,7 @@ Waiting for the associated effect of |animation| with |animation|. 1. If there is a [=pending play task=] - and [=start time=] is [=unresolved|resolved=], + and [=animation/start time=] is [=unresolved|resolved=], cancel that task and [=resolve a Promise|resolve=] the [=current ready promise=] of |animation| with |animation|. @@ -1982,7 +1983,7 @@ Waiting for the associated effect the [=DOM manipulation task source=]. 1. Make |animation|'s [=hold time=] [=unresolved=]. - 1. Make |animation|'s [=start time=] [=unresolved=]. + 1. Make |animation|'s [=animation/start time=] [=unresolved=].
@@ -2069,7 +2070,7 @@ Waiting for the associated effect : If |animation| is associated with a non-null [=timeline=] that is not [=monotonically increasing=], - the [=start time=] of |animation| is [=resolved=], + the [=animation/start time=] of |animation| is [=resolved=], [=associated effect end=] is not infinity, and either: @@ -2078,7 +2079,7 @@ Waiting for the associated effect * the |previous playback rate| ≥ 0 and the |new playback rate| < 0, - :: Set |animation|'s [=start time=] to the result of evaluating + :: Set |animation|'s [=animation/start time=] to the result of evaluating associated effect end − start time for |animation|. @@ -2180,7 +2181,7 @@ Waiting for the associated effect substituting an [=unresolved=] time value for the [=hold time=]. - 1. Let |animation|'s [=start time=] be + 1. Let |animation|'s [=animation/start time=] be the result of evaluating the following expression:
@@ -2193,7 +2194,7 @@ Waiting for the associated effect the [=timeline=] associated with |animation|. If [=pending playback rate=] is zero, - let |animation|'s [=start time=] be |timeline time|. + let |animation|'s [=animation/start time=] be |timeline time|. 1. [=Apply any pending playback rate=] on |animation|. @@ -2250,7 +2251,7 @@ Waiting for the associated effect : [=play state/idle=] :: The [=animation/current time=] of the animation is [=unresolved=] - and the [=start time=] of the animation is [=unresolved=] + and the [=animation/start time=] of the animation is [=unresolved=] and there are no pending tasks. In this state the animation has no effect. @@ -2283,7 +2284,7 @@ Waiting for the associated effect * The [=animation/current time=] of |animation| is [=unresolved=], and - * the [=start time=] of |animation| is [=unresolved=], + * the [=animation/start time=] of |animation| is [=unresolved=], and * |animation| does not have either a [=pending play task=] or a [=pending pause task=], @@ -2292,7 +2293,7 @@ Waiting for the associated effect : Either of the following conditions are true: * |animation| has a [=pending pause task=], or - * both the [=start time=] of |animation| is [=unresolved=] + * both the [=animation/start time=] of |animation| is [=unresolved=] and it does not have a [=pending play task=], :: → paused @@ -2323,7 +2324,7 @@ Waiting for the associated effect outside of its natural playback range can be converted from a [=play state/paused=] animation into a [=play state/finished=] animation - without restarting by setting the [=start time=] + without restarting by setting the [=animation/start time=] such as below:
@@ -2375,7 +2376,7 @@ Waiting for the associated effect To convert an animation time to timeline time a [=time value=], |time|, that is relative to - the [=start time=] of an animation, |animation|, + the [=animation/start time=] of an animation, |animation|, perform the following steps: 1. If |time| is [=unresolved=], @@ -2387,14 +2388,14 @@ Waiting for the associated effect 1. If |animation|'s [=playback rate=] is zero, return an [=unresolved=] [=time value=]. - 1. If |animation|'s [=start time=] is [=unresolved=], + 1. If |animation|'s [=animation/start time=] is [=unresolved=], return an [=unresolved=] [=time value=]. 1. Return the result of calculating time × (1 / playback rate) + start time, where |playback rate| and |start time| are - the [=playback rate=] and [=start time=] of |animation|, + the [=playback rate=] and [=animation/start time=] of |animation|, respectively.
@@ -2553,7 +2554,7 @@ Animation effects {#animation-effects} provided by the [=associated animation=] through a series of [=time spaces=]: * the local time space, - relative to the [=start time=] of the [=associated animation=], + relative to the [=animation/start time=] of the [=associated animation=], yielding the [=local time=] * the active time space, relative to the start of the [=active interval=], @@ -2615,7 +2616,7 @@ Animation effects {#animation-effects}
The relationship between - the [=start time=], [=start delay=], and [=active duration=] + the [=animation effect/start time=], [=start delay=], and [=active duration=] is illustrated below.
@@ -2626,7 +2627,7 @@ Animation effects {#animation-effects} Examples of the effect of the [=start delay=] on the endpoints of the [=active interval=].
(a) An animation effect with no delay; - the [=start time=] and beginning of the [=active interval=] + the [=animation effect/start time=] and beginning of the [=active interval=] are coincident.
(b) An animation effect with a positive delay; the beginning of the [=active interval=] @@ -2638,12 +2639,14 @@ Animation effects {#animation-effects}
-#### The start delay #### {#the-start-delay} +#### The start delay and start time #### {#the-start-delay} + The start time of an [=animation effect=] + is the [=animation/start time=] of its [=associated animation=]. The lower bound of the [=active interval=] - by default corresponds to the [=start time=] of the [=associated animation=], + by default corresponds to this [=animation effect/start time=], but can be shifted by the start delay, - which is a signed offset from the [=start time=] of the [=animation=]. + which is a signed offset (defaulting to zero). #### The active duration #### {#the-active-duration} @@ -4727,8 +4730,8 @@ The {{Animation}} interface {#the-animation-interface} : startTime :: - Returns the [=start time=] of this animation. - Setting this attribute updates the [=start time=] + Returns the [=animation/start time=] of this animation. + Setting this attribute updates the [=animation/start time=] using the procedure to [=set the start time=] of this object to the new value. @@ -5171,8 +5174,8 @@ The {{AnimationEffect}} interface {#the-animationeffect-interface} :: The [=start delay=], which represents the number of milliseconds - from the [=start time=] of the associated [=animation=] - to the start of the [=active interval=]. + from the [=animation effect/start time=] of the [=animation effect=] + to the start of its [=active interval=]. : endDelay :: @@ -5409,8 +5412,7 @@ The {{AnimationEffect}} interface {#the-animationeffect-interface} :: The [=end time=] of the [=animation effect=] expressed in milliseconds since zero [=local time=] - (that is, since the associated [=animation=]’s [=start time=] - if this [=animation effect=] is [=associated with an animation=]). + (that is, since the [=animation effect=]’s [=animation effect/start time=]). This corresponds to the end of the [=animation effect=]’s [=active interval=] plus any [=end delay=].