Include animations and transitions in the cascade
Instead of applying animations and transitions to styled elements,
include them in the cascade. This allows them to interact properly with
things like font-size and !important rules.
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Instead of applying animations and transitions to styled elements,
include them in the cascade. This allows them to interact properly with
things like font-size and !important rules.
This begins to address #26625 by properly applying CSS variables during
keyframe computation and no longer using `apply_declarations`. Instead,
walk the declarations, combining them into IntermediateComputedKeyframe,
maintaining declarations that modify CSS custom properties. Then compute
a set of AnimationValues for each keyframe and use those to produce
interpolated animation values.
Instead of recalculating the animation style every tick of an animation,
cache the computed values when animations change. In addition to being
more efficient, this will allow us to return animation rules as property
declarations because we don't need to consult the final style to produce
them.
This is based on compiling with `RUSTFLAGS="-W unused_crate_dependencies"` (CC https://github.com/rust-lang/rust/pull/72342) in a recent Nightly (more so than used in the tree as of this writing, CC https://github.com/servo/servo/issues/26661 for work-arounds).
Only one crate is actually removed from the dependency graph, others are still dependended from other places.
More Cargo.toml cleanups
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This is preparation for sharing this code with layout_2020 and
implementing selective off-the-main-thread animations.
We still look for nodes not in the flow tree in the layout thread.
This implementation is more-or-less on par with the one from layout_2013
and in some cases better. There are still some cases where we don't
return the correct "resolved value," but this is enough to test
animations and transitions.
This is a small step toward fixing #19242. The main idea is that the
clock for animations should advance as the event loop ticks. We
accomplish this by moving the clock from layout and naming it the
"animation timeline" which is the spec language. This should fix
flakiness with animations and transitions tests where a reflow could
move animations forward while script was running.
This change also starts to break out transition and animation events
into their own data structure, because it's quite likely that the next
step in fixing #19242 is to no longer send these events through a
channel.
This change corrects synchronization issues with animations, by
reworking the animation processing model to do a quick restyle and
incremental layout when ticking animations.
While this change adds overhead to animation ticks, the idea is that
this will be the fallback when synchronous behavior is required to
fulfill specification requirements. In the optimistic case, many
animations could be updated and applied off-the-main-thread and then
resynchronized when style information is queried by script.
Fixes#13865.
This refactor is preparation for implementing a specification
compliant transitions and animations processing model.
These data structures hold all the animation information about a single
node. Since adding, updating, and modifying animations for a single node
are all interdependent, it makes sense to start encapsulating animation
data and functionality into a single data structure. This also opens up
the possibility for easier concurrency in the future by more easily
allowing per-node mutexes.
Add support for canceling CSS transitions
This change adds support for canceling CSS transitions when a property is
no longer transitionable. Support for canceling and replacing CSS
transitions when the end value changes is still pending. This change
also takes advantage of updating the constellation message to fix a bug
where transition events could be sent for closed pipelines.
Fixes#15079.
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This change adds support for canceling CSS transitions when a property
is no longer transitionable or when an element becomes styled with
display:none. Support for canceling and replacing CSS transitions when
the end value changes is still pending. This change also takes advantage
of updating the constellation message to fix a bug where transition
events could be sent for closed pipelines.
Fixes#15079.
RuleTree::gc is now a safe method that any thread can call
at any time, and StrongRuleNode values can all be dropped
whenever their owner want to, on any thread.
There is no need to set the dirty descendants flag unsafely from the layout side
for elements with pending restyles, we can do that on the DOM side when draining
the restyles from the Document.
For clarity, I introduce <LayoutDom<Element>>::parent_node_ref to contain
the remaining unsafety bits out of composed_parent_node_ref which is more
complex than just a field access.
They don't do anything fancy so there is no additional unsafety calling them
compared to using LayoutDom in the first place, the usual story of all
those changes.
This safe method is the basic block to access element attributes from layout.
We reuse it in the other attr-related layout methods to remove a pretty big
source of rampant unsafe code between script and layout.
