This isn't spec'ed anywhere (since the whole Web Animations API <-> CSS
interaction isn't spec'ed yet) but it seems that changing animation-play-state
should not restart an idle animation.
If an author calls Cancel() on an animation then that animation should continue
to be idle until they call Play()/Pause() from the API. Cancelling an animation
and hanging on to it is a purely API-only feature and hence it's reasonable that
restoring it from this state is also an API-only feature.
One can imagine use-cases such as polyfilling where script wants to remove any
CSS Animations/Transitions run by the browser and replace them with something
else entirely. In that case, the script can call Cancel() on the animation and
be sure that the animation is going to stay out of the way even if something
else tweaks the animation-play-state.
This patch makes Cancel() call PostUpdate which clobbers certain state in style
so that animated style is correctly flushed when an animation is cancelled.
The main difficulty with this is that we *don't* want to call this when we're
cancelling an animation as a result of a style update or else we'll trigger
needless work. The pattern elsewhere has been to define a *FromStyle() method
for this case (e.g. CSSAnimation::PlayFromStyle, PauseFromStyle). This isn't
ideal because there's always the danger we will forget to call the appropriate
*FromStyle method. It is, however, consistent. Hopefully in bug 1151731 we'll
find a better way of expressing this.
This patch is a fairly minimal rename of the AnimationPlayer interface. It
leaves a bunch of local variables and helper classes still using the word
"player". These will be addressed in subsequent patches that don't require DOM
peer review.
This patch also tightens up a one or two references to 'target effect' replacing
them with just 'effect'. This is because 'target effect' is longer and easily
confused with 'target element'. 'effect' should be sufficient. 'target element'
is a term from the Web Animations specification and in that context, simply
referring to the 'effect' would sound a little odd.
There are still some other references to "source" in AnimationPlayer such as
HasInPlayerSource and UpdateSourceContent. These are renamed in a subsequent
patch (that doesn't require DOM peer review).
We define KeyframeEffectReadonly in KeyframeEffect.cpp since Web Animations also
defines KeyframeEffect and when we come to implement that I expect we'll define
it in the same class, maybe even using the same object.
This patch also adds a few missing includes in places where
KeyframeEffectReadonly is used so that we're not just cargo-culting it in.
This avoids some extra work that was added in bug 1125455 now that we
have a mechanism for detecting when animations start and stop being in
effect (introduced in patch 7).
This is also needed to prevent infinite recursion in patch 9.
This is the main patch for the bug; it makes us use the mechanism added
in bug 1125455 to avoid sending animations that aren't currently
applying to the compositor.
Patch 7 is needed to make this code rerun in all the cases where we need
to rerun it, though.
IsPaused is used in nsAnimationManager to detect if a newly created animation
should be paused. It is also used inside AnimationPlayer::IsRunning which is
used to determine what animations to send to the compositor (we don't send
paused animations to the compositor). In all these cases we want to treat paused
animations and pause-pending animations alike.
This patch updates IsPaused to include also pause-pending animations. At the
same time it renames IsPaused to IsPausedOrPausing to reflect the change in
behavior.
This patch also adjusts a few nearby one-line functions to put the opening brace
on a new line since apparently this is what the coding style says to do.
Note that this means that when we start transitions, we post restyles
that are processed during the current restyling operation, rather than
in a later phase. This depends on patch 11, which makes the transition
manager skip style changes that it posts while starting transitions, to
ensure that this doesn't lead to an infinite loop. This also depends on
patch 16, which only consumes restyle data for the primary frame, to
ensure that the animation restyles posted are processed properly. It
also depends on patch 14, which makes us retain data on finished
transitions, to avoid triggering extra transitions on descendants when
both an ancestor and a descendant transition an inherited property, and
the descendant does so faster.
This fixes a known failure in layout/style/test/test_animations.html and
test_animations_omta.html (as visible in the patch). I believe this is
because this patch changes us to compute keyframe values for animations
on top of a style context *with* animation data rather than one without,
which means what we're computing them on top of changes each time. (The
purpose of patch 3 was to avoid this in the case where avoiding it
matters, i.e., implicit 0% and 100% keyframes.)
This is needed to make the tests for bug 686656 in test_animations.html
pass.
Note that once the rest of bug 960465 happens this will start producing
slightly different results in edge cases, since we will only be skipping
animation styles for the element itself and not for ancestors. However,
both old and new behaviors are incorrect, since per spec we should be
updating the base values dynamically (bug 1064915).
This patch adds a means of terminating an animation so that is has no effect.
The procedure is defined by Web Animations:
http://w3c.github.io/web-animations/#cancelling-a-player-section
We don't implement all of this, however, since we don't currently support the
finished promise or custom effects.
In a later bug we will expose this as the cancel() method on AnimationPlayer.
We call this method for terminated animations in nsAnimationManager and
nsTransitionManager to ensure they get removed from the pending player tracker
and so that, for example, the ready promise of CSS Animation player objects is
rejected when the corresponding item is removed from animation-name.
Now that there is a public accessor for mStartTime, we can make it a protected
member of AnimationPlayer. The only time mStartTime is ever set is when playing
the animation so we can replace external modifications to mStartTime with calls
to Play(). This simplifies implementing deferred starting of animations
in bug 927349 by isolating the deferred playback logic to AnimationPlayer.
Note that even when we call PauseFromStyle immediately afterwards we still need
to call PlayFromStyle (or Play) first in order to resolve the time at which the
player should be paused. A newly created player doesn't have a current time so
if we were simply to call pause it wouldn't pause at the start of the animation
as we might expect. The call to Play(FromStyle) will cause the current time to
become zero and then we pause at that time.
