Both ElementAnimations and ElementTransitions have an EnsureStyleRuleFor method.
The ElementAnimations version is a more general of the ElementTransitions one
with the exception that the ElementTransitions version checks for finished
transitions. This patch moves the code from ElementAnimations to
CommonElementAnimationData with one minor change: adding the checks for finished
transitions. The ElementTransitions version is removed.
Since the ElementAnimations version contains a second parameter, aIsThrottled,
callers of ElementTransitions must include this extra parameter. In
a subsequent patch we add an enum for this parameter to make call sites easier
to read.
The ElementAnimations version also sets the mNeedsRefreshes member so at the
same time we move mNeedsRefreshes to CommonElementAnimationData. Furthermore,
since the ElementAnimations version which we have adopted returns early if
mNeedsRefreshes is false, this patch ensures that when we call
EnsureStyleRuleFor from ElementTransitions::WalkTransitionRule, we set
mNeedsRefreshes to true first.
Another difference to account for is that the ElementTransitions version of
EnsureStyleRuleFor *always* sets mStyleRule (even if it doesn't add anything to
it) where as the ElementAnimations version only creates the rule when necessary
so we need to add a check to ElementTransitions::WalkTransitionRule that
mStyleRule is actually set before using it.
Now that an animation's delay is part of AnimationTiming--the struct we pass to
GetComputedTimingAt--it makes sense to act on it in GetComputedTimingAt.
This also happens to bring the procedures here closer to the algorithm
definitions in Web Animations.
As part of this refactoring, this patch converts ElementAnimation::IsRunningAt
to use GetComputedTiming since the previous approach no longer works now that
GetLocalTimeAt (nee ElapsedDurationAt) no longer handles delays. This also
removes duplicated logic.
Also, previously ElapsedDurationAt would assert if called on a finished
transition since TimeDuration's - operator wouldn't like the null mStartTime.
This patch adds an assertion for this case to GetLocalTimeAt to ease debugging.
One of the main differences in handling a list of transitions vs a list of
regular animations is that when we are dealing with a list of transitions we
need to check for transitions that have finished and are about to be discarded
but need to be retained temporarily to provide correct triggering of subsequent
transitions. Such transitions are marked as "removed sentinels" and are ignored
for most operations.
This patch moves the methods for setting and checking such transitions to the
base class ElementAnimation so that we can treat animations and transitions
alike without having to downcast or do obscure checks for mStartTime.IsNull()
(which equates to checking if the animation is a "removed sentinel" but is not
particularly clear).
In the process, this patch renames said methods to Is/SetFinishedTransition
since hopefully that is a little easier to understand at a glance.
This patch is the first part in preparing the way to merge ElementTransitions
with CommonElementAnimationData (which we'll eventually rename to something
nicer).
Here we move mTiming from CommonElementAnimationData to the AnimationTiming
struct. While this is not strictly necessary in order to do the later
refactoring it makes it simpler since it:
- Divides time calculation into calculation based on dynamic play state (the
responsibility of animation players in Web Animations terms) and static
author-specified timing parameters (a property of animations in Web Animations
terms).
- In future we will probably put animations on the compositor during their
delay phase so we will want the delay to be present in the AnimationTiming
struct then.
- Makes AnimationTiming line up with the dictionary of the same name in Web
Animations.
