/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
//! CSS transitions and animations.
// NOTE(emilio): This code isn't really executed in Gecko, but we don't want to
// compile it out so that people remember it exists.
use crate::bezier::Bezier;
use crate::context::{CascadeInputs, SharedStyleContext};
use crate::dom::{OpaqueNode, TDocument, TElement, TNode};
use crate::properties::animated_properties::{AnimationValue, AnimationValueMap};
use crate::properties::longhands::animation_direction::computed_value::single_value::T as AnimationDirection;
use crate::properties::longhands::animation_fill_mode::computed_value::single_value::T as AnimationFillMode;
use crate::properties::longhands::animation_play_state::computed_value::single_value::T as AnimationPlayState;
use crate::properties::AnimationDeclarations;
use crate::properties::{
ComputedValues, Importance, LonghandId, LonghandIdSet, PropertyDeclarationBlock,
PropertyDeclarationId,
};
use crate::rule_tree::CascadeLevel;
use crate::selector_parser::PseudoElement;
use crate::shared_lock::{Locked, SharedRwLock};
use crate::style_resolver::StyleResolverForElement;
use crate::stylesheets::keyframes_rule::{KeyframesAnimation, KeyframesStep, KeyframesStepValue};
use crate::values::animated::{Animate, Procedure};
use crate::values::computed::{Time, TimingFunction};
use crate::values::generics::box_::AnimationIterationCount;
use crate::values::generics::easing::{
StepPosition, TimingFunction as GenericTimingFunction, TimingKeyword,
};
use crate::Atom;
use fxhash::FxHashMap;
use parking_lot::RwLock;
use servo_arc::Arc;
use std::fmt;
/// Represents an animation for a given property.
#[derive(Clone, Debug, MallocSizeOf)]
pub struct PropertyAnimation {
/// The value we are animating from.
from: AnimationValue,
/// The value we are animating to.
to: AnimationValue,
/// The timing function of this `PropertyAnimation`.
timing_function: TimingFunction,
/// The duration of this `PropertyAnimation` in seconds.
pub duration: f64,
}
impl PropertyAnimation {
/// Returns the given property longhand id.
pub fn property_id(&self) -> LonghandId {
debug_assert_eq!(self.from.id(), self.to.id());
self.from.id()
}
fn from_longhand(
longhand: LonghandId,
timing_function: TimingFunction,
duration: Time,
old_style: &ComputedValues,
new_style: &ComputedValues,
) -> Option<PropertyAnimation> {
// FIXME(emilio): Handle the case where old_style and new_style's writing mode differ.
let longhand = longhand.to_physical(new_style.writing_mode);
let from = AnimationValue::from_computed_values(longhand, old_style)?;
let to = AnimationValue::from_computed_values(longhand, new_style)?;
let duration = duration.seconds() as f64;
if from == to || duration == 0.0 {
return None;
}
Some(PropertyAnimation {
from,
to,
timing_function,
duration,
})
}
/// The output of the timing function given the progress ration of this animation.
fn timing_function_output(&self, progress: f64) -> f64 {
let epsilon = 1. / (200. * self.duration);
match self.timing_function {
GenericTimingFunction::CubicBezier { x1, y1, x2, y2 } => {
Bezier::new(x1, y1, x2, y2).solve(progress, epsilon)
},
GenericTimingFunction::Steps(steps, pos) => {
let mut current_step = (progress * (steps as f64)).floor() as i32;
if pos == StepPosition::Start ||
pos == StepPosition::JumpStart ||
pos == StepPosition::JumpBoth
{
current_step = current_step + 1;
}
// FIXME: We should update current_step according to the "before flag".
// In order to get the before flag, we have to know the current animation phase
// and whether the iteration is reversed. For now, we skip this calculation.
// (i.e. Treat before_flag is unset,)
// https://drafts.csswg.org/css-easing/#step-timing-function-algo
if progress >= 0.0 && current_step < 0 {
current_step = 0;
}
let jumps = match pos {
StepPosition::JumpBoth => steps + 1,
StepPosition::JumpNone => steps - 1,
StepPosition::JumpStart |
StepPosition::JumpEnd |
StepPosition::Start |
StepPosition::End => steps,
};
if progress <= 1.0 && current_step > jumps {
current_step = jumps;
}
(current_step as f64) / (jumps as f64)
},
GenericTimingFunction::Keyword(keyword) => {
let bezier = match keyword {
TimingKeyword::Linear => return progress,
TimingKeyword::Ease => Bezier::new(0.25, 0.1, 0.25, 1.),
TimingKeyword::EaseIn => Bezier::new(0.42, 0., 1., 1.),
TimingKeyword::EaseOut => Bezier::new(0., 0., 0.58, 1.),
TimingKeyword::EaseInOut => Bezier::new(0.42, 0., 0.58, 1.),
};
bezier.solve(progress, epsilon)
},
}
}
/// Update the given animation at a given point of progress.
fn calculate_value(&self, progress: f64) -> Result<AnimationValue, ()> {
let procedure = Procedure::Interpolate {
progress: self.timing_function_output(progress),
};
self.from.animate(&self.to, procedure)
}
}
/// This structure represents the state of an animation.
#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
pub enum AnimationState {
/// The animation has been created, but is not running yet. This state
/// is also used when an animation is still in the first delay phase.
Pending,
/// This animation is currently running.
Running,
/// This animation is paused. The inner field is the percentage of progress
/// when it was paused, from 0 to 1.
Paused(f64),
/// This animation has finished.
Finished,
/// This animation has been canceled.
Canceled,
}
impl AnimationState {
/// Whether or not this state requires its owning animation to be ticked.
fn needs_to_be_ticked(&self) -> bool {
*self == AnimationState::Running || *self == AnimationState::Pending
}
}
/// This structure represents a keyframes animation current iteration state.
///
/// If the iteration count is infinite, there's no other state, otherwise we
/// have to keep track the current iteration and the max iteration count.
#[derive(Clone, Debug, MallocSizeOf)]
pub enum KeyframesIterationState {
/// Infinite iterations with the current iteration count.
Infinite(f64),
/// Current and max iterations.
Finite(f64, f64),
}
/// A temporary data structure used when calculating ComputedKeyframes for an
/// animation. This data structure is used to collapse information for steps
/// which may be spread across multiple keyframe declarations into a single
/// instance per `start_percentage`.
struct IntermediateComputedKeyframe {
declarations: PropertyDeclarationBlock,
timing_function: Option<TimingFunction>,
start_percentage: f32,
}
impl IntermediateComputedKeyframe {
fn new(start_percentage: f32) -> Self {
IntermediateComputedKeyframe {
declarations: PropertyDeclarationBlock::new(),
timing_function: None,
start_percentage,
}
}
/// Walk through all keyframe declarations and combine all declarations with the
/// same `start_percentage` into individual `IntermediateComputedKeyframe`s.
fn generate_for_keyframes(
animation: &KeyframesAnimation,
context: &SharedStyleContext,
base_style: &ComputedValues,
) -> Vec<Self> {
let mut intermediate_steps: Vec<Self> = Vec::with_capacity(animation.steps.len());
let mut current_step = IntermediateComputedKeyframe::new(0.);
for step in animation.steps.iter() {
let start_percentage = step.start_percentage.0;
if start_percentage != current_step.start_percentage {
let new_step = IntermediateComputedKeyframe::new(start_percentage);
intermediate_steps.push(std::mem::replace(&mut current_step, new_step));
}
current_step.update_from_step(step, context, base_style);
}
intermediate_steps.push(current_step);
// We should always have a first and a last step, even if these are just
// generated by KeyframesStepValue::ComputedValues.
debug_assert!(intermediate_steps.first().unwrap().start_percentage == 0.);
debug_assert!(intermediate_steps.last().unwrap().start_percentage == 1.);
intermediate_steps
}
fn update_from_step(
&mut self,
step: &KeyframesStep,
context: &SharedStyleContext,
base_style: &ComputedValues,
) {
// Each keyframe declaration may optionally specify a timing function, falling
// back to the one defined global for the animation.
let guard = &context.guards.author;
if let Some(timing_function) = step.get_animation_timing_function(&guard) {
self.timing_function = Some(timing_function.to_computed_value_without_context());
}
let block = match step.value {
KeyframesStepValue::ComputedValues => return,
KeyframesStepValue::Declarations { ref block } => block,
};
// Filter out !important, non-animatable properties, and the
// 'display' property (which is only animatable from SMIL).
let guard = block.read_with(&guard);
for declaration in guard.normal_declaration_iter() {
if let PropertyDeclarationId::Longhand(id) = declaration.id() {
if id == LonghandId::Display {
continue;
}
if !id.is_animatable() {
continue;
}
}
self.declarations.push(
declaration.to_physical(base_style.writing_mode),
Importance::Normal,
);
}
}
fn resolve_style<E>(
self,
element: E,
context: &SharedStyleContext,
base_style: &Arc<ComputedValues>,
resolver: &mut StyleResolverForElement<E>,
) -> Arc<ComputedValues>
where
E: TElement,
{
if !self.declarations.any_normal() {
return base_style.clone();
}
let document = element.as_node().owner_doc();
let locked_block = Arc::new(document.shared_lock().wrap(self.declarations));
let mut important_rules_changed = false;
let rule_node = base_style.rules().clone();
let new_node = context.stylist.rule_tree().update_rule_at_level(
CascadeLevel::Animations,
Some(locked_block.borrow_arc()),
&rule_node,
&context.guards,
&mut important_rules_changed,
);
if new_node.is_none() {
return base_style.clone();
}
let inputs = CascadeInputs {
rules: new_node,
visited_rules: base_style.visited_rules().cloned(),
};
resolver
.cascade_style_and_visited_with_default_parents(inputs)
.0
}
}
/// A single computed keyframe for a CSS Animation.
#[derive(Clone, MallocSizeOf)]
struct ComputedKeyframe {
/// The timing function to use for transitions between this step
/// and the next one.
timing_function: TimingFunction,
/// The starting percentage (a number between 0 and 1) which represents
/// at what point in an animation iteration this step is.
start_percentage: f32,
/// The animation values to transition to and from when processing this
/// keyframe animation step.
values: Vec<AnimationValue>,
}
impl ComputedKeyframe {
fn generate_for_keyframes<E>(
element: E,
animation: &KeyframesAnimation,
context: &SharedStyleContext,
base_style: &Arc<ComputedValues>,
default_timing_function: TimingFunction,
resolver: &mut StyleResolverForElement<E>,
) -> Vec<Self>
where
E: TElement,
{
let mut animating_properties = LonghandIdSet::new();
for property in animation.properties_changed.iter() {
debug_assert!(property.is_animatable());
animating_properties.insert(property.to_physical(base_style.writing_mode));
}
let animation_values_from_style: Vec<AnimationValue> = animating_properties
.iter()
.map(|property| {
AnimationValue::from_computed_values(property, &**base_style)
.expect("Unexpected non-animatable property.")
})
.collect();
let intermediate_steps =
IntermediateComputedKeyframe::generate_for_keyframes(animation, context, base_style);
let mut computed_steps: Vec<Self> = Vec::with_capacity(intermediate_steps.len());
for (step_index, step) in intermediate_steps.into_iter().enumerate() {
let start_percentage = step.start_percentage;
let timing_function = step.timing_function.unwrap_or(default_timing_function);
let properties_changed_in_step = step.declarations.longhands().clone();
let step_style = step.resolve_style(element, context, base_style, resolver);
let values = {
// If a value is not set in a property declaration we use the value from
// the style for the first and last keyframe. For intermediate ones, we
// use the value from the previous keyframe.
//
// TODO(mrobinson): According to the spec, we should use an interpolated
// value for properties missing from keyframe declarations.
let default_values = if start_percentage == 0. || start_percentage == 1.0 {
&animation_values_from_style
} else {
debug_assert!(step_index != 0);
&computed_steps[step_index - 1].values
};
// For each property that is animating, pull the value from the resolved
// style for this step if it's in one of the declarations. Otherwise, we
// use the default value from the set we calculated above.
animating_properties
.iter()
.zip(default_values.iter())
.map(|(longhand, default_value)| {
if properties_changed_in_step.contains(longhand) {
AnimationValue::from_computed_values(longhand, &step_style)
.unwrap_or_else(|| default_value.clone())
} else {
default_value.clone()
}
})
.collect()
};
computed_steps.push(ComputedKeyframe {
timing_function,
start_percentage,
values,
});
}
computed_steps
}
}
/// A CSS Animation
#[derive(Clone, MallocSizeOf)]
pub struct Animation {
/// The name of this animation as defined by the style.
pub name: Atom,
/// The properties that change in this animation.
properties_changed: LonghandIdSet,
/// The computed style for each keyframe of this animation.
computed_steps: Vec<ComputedKeyframe>,
/// The time this animation started at, which is the current value of the animation
/// timeline when this animation was created plus any animation delay.
pub started_at: f64,
/// The duration of this animation.
pub duration: f64,
/// The delay of the animation.
pub delay: f64,
/// The `animation-fill-mode` property of this animation.
pub fill_mode: AnimationFillMode,
/// The current iteration state for the animation.
pub iteration_state: KeyframesIterationState,
/// Whether this animation is paused.
pub state: AnimationState,
/// The declared animation direction of this animation.
pub direction: AnimationDirection,
/// The current animation direction. This can only be `normal` or `reverse`.
pub current_direction: AnimationDirection,
/// The original cascade style, needed to compute the generated keyframes of
/// the animation.
#[ignore_malloc_size_of = "ComputedValues"]
pub cascade_style: Arc<ComputedValues>,
/// Whether or not this animation is new and or has already been tracked
/// by the script thread.
pub is_new: bool,
}
impl Animation {
/// Whether or not this animation is cancelled by changes from a new style.
fn is_cancelled_in_new_style(&self, new_style: &Arc<ComputedValues>) -> bool {
let index = new_style
.get_box()
.animation_name_iter()
.position(|animation_name| Some(&self.name) == animation_name.as_atom());
let index = match index {
Some(index) => index,
None => return true,
};
new_style.get_box().animation_duration_mod(index).seconds() == 0.
}
/// Given the current time, advances this animation to the next iteration,
/// updates times, and then toggles the direction if appropriate. Otherwise
/// does nothing. Returns true if this animation has iterated.
pub fn iterate_if_necessary(&mut self, time: f64) -> bool {
if !self.iteration_over(time) {
return false;
}
// Only iterate animations that are currently running.
if self.state != AnimationState::Running {
return false;
}
if self.on_last_iteration() {
return false;
}
self.iterate();
true
}
fn iterate(&mut self) {
debug_assert!(!self.on_last_iteration());
if let KeyframesIterationState::Finite(ref mut current, max) = self.iteration_state {
*current = (*current + 1.).min(max);
}
if let AnimationState::Paused(ref mut progress) = self.state {
debug_assert!(*progress > 1.);
*progress -= 1.;
}
// Update the next iteration direction if applicable.
self.started_at += self.duration;
match self.direction {
AnimationDirection::Alternate | AnimationDirection::AlternateReverse => {
self.current_direction = match self.current_direction {
AnimationDirection::Normal => AnimationDirection::Reverse,
AnimationDirection::Reverse => AnimationDirection::Normal,
_ => unreachable!(),
};
},
_ => {},
}
}
/// A number (> 0 and <= 1) which represents the fraction of a full iteration
/// that the current iteration of the animation lasts. This will be less than 1
/// if the current iteration is the fractional remainder of a non-integral
/// iteration count.
pub fn current_iteration_end_progress(&self) -> f64 {
match self.iteration_state {
KeyframesIterationState::Finite(current, max) => (max - current).min(1.),
KeyframesIterationState::Infinite(_) => 1.,
}
}
/// The duration of the current iteration of this animation which may be less
/// than the animation duration if it has a non-integral iteration count.
pub fn current_iteration_duration(&self) -> f64 {
self.current_iteration_end_progress() * self.duration
}
/// Whether or not the current iteration is over. Note that this method assumes that
/// the animation is still running.
fn iteration_over(&self, time: f64) -> bool {
time > (self.started_at + self.current_iteration_duration())
}
/// Assuming this animation is running, whether or not it is on the last iteration.
fn on_last_iteration(&self) -> bool {
match self.iteration_state {
KeyframesIterationState::Finite(current, max) => current >= (max - 1.),
KeyframesIterationState::Infinite(_) => false,
}
}
/// Whether or not this animation has finished at the provided time. This does
/// not take into account canceling i.e. when an animation or transition is
/// canceled due to changes in the style.
pub fn has_ended(&self, time: f64) -> bool {
if !self.on_last_iteration() {
return false;
}
let progress = match self.state {
AnimationState::Finished => return true,
AnimationState::Paused(progress) => progress,
AnimationState::Running => (time - self.started_at) / self.duration,
AnimationState::Pending | AnimationState::Canceled => return false,
};
progress >= self.current_iteration_end_progress()
}
/// Updates the appropiate state from other animation.
///
/// This happens when an animation is re-submitted to layout, presumably
/// because of an state change.
///
/// There are some bits of state we can't just replace, over all taking in
/// account times, so here's that logic.
pub fn update_from_other(&mut self, other: &Self, now: f64) {
use self::AnimationState::*;
debug!(
"KeyframesAnimationState::update_from_other({:?}, {:?})",
self, other
);
// NB: We shall not touch the started_at field, since we don't want to
// restart the animation.
let old_started_at = self.started_at;
let old_duration = self.duration;
let old_direction = self.current_direction;
let old_state = self.state.clone();
let old_iteration_state = self.iteration_state.clone();
*self = other.clone();
self.started_at = old_started_at;
self.current_direction = old_direction;
// Don't update the iteration count, just the iteration limit.
// TODO: see how changing the limit affects rendering in other browsers.
// We might need to keep the iteration count even when it's infinite.
match (&mut self.iteration_state, old_iteration_state) {
(
&mut KeyframesIterationState::Finite(ref mut iters, _),
KeyframesIterationState::Finite(old_iters, _),
) => *iters = old_iters,
_ => {},
}
// Don't pause or restart animations that should remain finished.
// We call mem::replace because `has_ended(...)` looks at `Animation::state`.
let new_state = std::mem::replace(&mut self.state, Running);
if old_state == Finished && self.has_ended(now) {
self.state = Finished;
} else {
self.state = new_state;
}
// If we're unpausing the animation, fake the start time so we seem to
// restore it.
//
// If the animation keeps paused, keep the old value.
//
// If we're pausing the animation, compute the progress value.
match (&mut self.state, &old_state) {
(&mut Pending, &Paused(progress)) => {
self.started_at = now - (self.duration * progress);
},
(&mut Paused(ref mut new), &Paused(old)) => *new = old,
(&mut Paused(ref mut progress), &Running) => {
*progress = (now - old_started_at) / old_duration
},
_ => {},
}
// Try to detect when we should skip straight to the running phase to
// avoid sending multiple animationstart events.
if self.state == Pending && self.started_at <= now && old_state != Pending {
self.state = Running;
}
}
/// Fill in an `AnimationValueMap` with values calculated from this animation at
/// the given time value.
fn get_property_declaration_at_time(&self, now: f64, map: &mut AnimationValueMap) {
debug_assert!(!self.computed_steps.is_empty());
let total_progress = match self.state {
AnimationState::Running | AnimationState::Pending | AnimationState::Finished => {
(now - self.started_at) / self.duration
},
AnimationState::Paused(progress) => progress,
AnimationState::Canceled => return,
};
if total_progress < 0. &&
self.fill_mode != AnimationFillMode::Backwards &&
self.fill_mode != AnimationFillMode::Both
{
return;
}
if self.has_ended(now) &&
self.fill_mode != AnimationFillMode::Forwards &&
self.fill_mode != AnimationFillMode::Both
{
return;
}
let total_progress = total_progress
.min(self.current_iteration_end_progress())
.max(0.0);
// Get the indices of the previous (from) keyframe and the next (to) keyframe.
let next_keyframe_index;
let prev_keyframe_index;
let num_steps = self.computed_steps.len();
match self.current_direction {
AnimationDirection::Normal => {
next_keyframe_index = self
.computed_steps
.iter()
.position(|step| total_progress as f32 <= step.start_percentage);
prev_keyframe_index = next_keyframe_index
.and_then(|pos| if pos != 0 { Some(pos - 1) } else { None })
.unwrap_or(0);
},
AnimationDirection::Reverse => {
next_keyframe_index = self
.computed_steps
.iter()
.rev()
.position(|step| total_progress as f32 <= 1. - step.start_percentage)
.map(|pos| num_steps - pos - 1);
prev_keyframe_index = next_keyframe_index
.and_then(|pos| {
if pos != num_steps - 1 {
Some(pos + 1)
} else {
None
}
})
.unwrap_or(num_steps - 1)
},
_ => unreachable!(),
}
debug!(
"Animation::get_property_declaration_at_time: keyframe from {:?} to {:?}",
prev_keyframe_index, next_keyframe_index
);
let prev_keyframe = &self.computed_steps[prev_keyframe_index];
let next_keyframe = match next_keyframe_index {
Some(index) => &self.computed_steps[index],
None => return,
};
// If we only need to take into account one keyframe, then exit early
// in order to avoid doing more work.
let mut add_declarations_to_map = |keyframe: &ComputedKeyframe| {
for value in keyframe.values.iter() {
map.insert(value.id(), value.clone());
}
};
if total_progress <= 0.0 {
add_declarations_to_map(&prev_keyframe);
return;
}
if total_progress >= 1.0 {
add_declarations_to_map(&next_keyframe);
return;
}
let percentage_between_keyframes =
(next_keyframe.start_percentage - prev_keyframe.start_percentage).abs() as f64;
let duration_between_keyframes = percentage_between_keyframes * self.duration;
let direction_aware_prev_keyframe_start_percentage = match self.current_direction {
AnimationDirection::Normal => prev_keyframe.start_percentage as f64,
AnimationDirection::Reverse => 1. - prev_keyframe.start_percentage as f64,
_ => unreachable!(),
};
let progress_between_keyframes = (total_progress -
direction_aware_prev_keyframe_start_percentage) /
percentage_between_keyframes;
for (from, to) in prev_keyframe.values.iter().zip(next_keyframe.values.iter()) {
let animation = PropertyAnimation {
from: from.clone(),
to: to.clone(),
timing_function: prev_keyframe.timing_function,
duration: duration_between_keyframes as f64,
};
if let Ok(value) = animation.calculate_value(progress_between_keyframes) {
map.insert(value.id(), value);
}
}
}
}
impl fmt::Debug for Animation {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("Animation")
.field("name", &self.name)
.field("started_at", &self.started_at)
.field("duration", &self.duration)
.field("delay", &self.delay)
.field("iteration_state", &self.iteration_state)
.field("state", &self.state)
.field("direction", &self.direction)
.field("current_direction", &self.current_direction)
.field("cascade_style", &())
.finish()
}
}
/// A CSS Transition
#[derive(Clone, Debug, MallocSizeOf)]
pub struct Transition {
/// The start time of this transition, which is the current value of the animation
/// timeline when this transition was created plus any animation delay.
pub start_time: f64,
/// The delay used for this transition.
pub delay: f64,
/// The internal style `PropertyAnimation` for this transition.
pub property_animation: PropertyAnimation,
/// The state of this transition.
pub state: AnimationState,
/// Whether or not this transition is new and or has already been tracked
/// by the script thread.
pub is_new: bool,
/// If this `Transition` has been replaced by a new one this field is
/// used to help produce better reversed transitions.
pub reversing_adjusted_start_value: AnimationValue,
/// If this `Transition` has been replaced by a new one this field is
/// used to help produce better reversed transitions.
pub reversing_shortening_factor: f64,
}
impl Transition {
fn update_for_possibly_reversed_transition(
&mut self,
replaced_transition: &Transition,
delay: f64,
now: f64,
) {
// If we reach here, we need to calculate a reversed transition according to
// https://drafts.csswg.org/css-transitions/#starting
//
// "...if the reversing-adjusted start value of the running transition
// is the same as the value of the property in the after-change style (see
// the section on reversing of transitions for why these case exists),
// implementations must cancel the running transition and start
// a new transition..."
if replaced_transition.reversing_adjusted_start_value != self.property_animation.to {
return;
}
// "* reversing-adjusted start value is the end value of the running transition"
let replaced_animation = &replaced_transition.property_animation;
self.reversing_adjusted_start_value = replaced_animation.to.clone();
// "* reversing shortening factor is the absolute value, clamped to the
// range [0, 1], of the sum of:
// 1. the output of the timing function of the old transition at the
// time of the style change event, times the reversing shortening
// factor of the old transition
// 2. 1 minus the reversing shortening factor of the old transition."
let transition_progress = ((now - replaced_transition.start_time) /
(replaced_transition.property_animation.duration))
.min(1.0)
.max(0.0);
let timing_function_output = replaced_animation.timing_function_output(transition_progress);
let old_reversing_shortening_factor = replaced_transition.reversing_shortening_factor;
self.reversing_shortening_factor = ((timing_function_output *
old_reversing_shortening_factor) +
(1.0 - old_reversing_shortening_factor))
.abs()
.min(1.0)
.max(0.0);
// "* start time is the time of the style change event plus:
// 1. if the matching transition delay is nonnegative, the matching
// transition delay, or.
// 2. if the matching transition delay is negative, the product of the new
// transition’s reversing shortening factor and the matching transition delay,"
self.start_time = if delay >= 0. {
now + delay
} else {
now + (self.reversing_shortening_factor * delay)
};
// "* end time is the start time plus the product of the matching transition
// duration and the new transition’s reversing shortening factor,"
self.property_animation.duration *= self.reversing_shortening_factor;
// "* start value is the current value of the property in the running transition,
// * end value is the value of the property in the after-change style,"
let procedure = Procedure::Interpolate {
progress: timing_function_output,
};
match replaced_animation
.from
.animate(&replaced_animation.to, procedure)
{
Ok(new_start) => self.property_animation.from = new_start,
Err(..) => {},
}
}
/// Whether or not this animation has ended at the provided time. This does
/// not take into account canceling i.e. when an animation or transition is
/// canceled due to changes in the style.
pub fn has_ended(&self, time: f64) -> bool {
time >= self.start_time + (self.property_animation.duration)
}
/// Update the given animation at a given point of progress.
pub fn calculate_value(&self, time: f64) -> Option<AnimationValue> {
let progress = (time - self.start_time) / (self.property_animation.duration);
if progress < 0.0 {
return None;
}
self.property_animation
.calculate_value(progress.min(1.0))
.ok()
}
}
/// Holds the animation state for a particular element.
#[derive(Debug, Default, MallocSizeOf)]
pub struct ElementAnimationSet {
/// The animations for this element.
pub animations: Vec<Animation>,
/// The transitions for this element.
pub transitions: Vec<Transition>,
/// Whether or not this ElementAnimationSet has had animations or transitions
/// which have been added, removed, or had their state changed.
pub dirty: bool,
}
impl ElementAnimationSet {
/// Cancel all animations in this `ElementAnimationSet`. This is typically called
/// when the element has been removed from the DOM.
pub fn cancel_all_animations(&mut self) {
self.dirty = !self.animations.is_empty();
for animation in self.animations.iter_mut() {
animation.state = AnimationState::Canceled;
}
self.cancel_active_transitions();
}
fn cancel_active_transitions(&mut self) {
for transition in self.transitions.iter_mut() {
if transition.state != AnimationState::Finished {
self.dirty = true;
transition.state = AnimationState::Canceled;
}
}
}
/// Apply all active animations.
pub fn apply_active_animations(
&self,
context: &SharedStyleContext,
style: &mut Arc<ComputedValues>,
) {
let now = context.current_time_for_animations;
let mutable_style = Arc::make_mut(style);
if let Some(map) = self.get_value_map_for_active_animations(now) {
for value in map.values() {
value.set_in_style_for_servo(mutable_style);
}
}
if let Some(map) = self.get_value_map_for_active_transitions(now) {
for value in map.values() {
value.set_in_style_for_servo(mutable_style);
}
}
}
/// Clear all canceled animations and transitions from this `ElementAnimationSet`.
pub fn clear_canceled_animations(&mut self) {
self.animations
.retain(|animation| animation.state != AnimationState::Canceled);
self.transitions
.retain(|animation| animation.state != AnimationState::Canceled);
}
/// Whether this `ElementAnimationSet` is empty, which means it doesn't
/// hold any animations in any state.
pub fn is_empty(&self) -> bool {
self.animations.is_empty() && self.transitions.is_empty()
}
/// Whether or not this state needs animation ticks for its transitions
/// or animations.
pub fn needs_animation_ticks(&self) -> bool {
self.animations
.iter()
.any(|animation| animation.state.needs_to_be_ticked()) ||
self.transitions
.iter()
.any(|transition| transition.state.needs_to_be_ticked())
}
/// The number of running animations and transitions for this `ElementAnimationSet`.
pub fn running_animation_and_transition_count(&self) -> usize {
self.animations
.iter()
.filter(|animation| animation.state.needs_to_be_ticked())
.count() +
self.transitions
.iter()
.filter(|transition| transition.state.needs_to_be_ticked())
.count()
}
/// If this `ElementAnimationSet` has any any active animations.
pub fn has_active_animation(&self) -> bool {
self.animations
.iter()
.any(|animation| animation.state != AnimationState::Canceled)
}
/// If this `ElementAnimationSet` has any any active transitions.
pub fn has_active_transition(&self) -> bool {
self.transitions
.iter()
.any(|transition| transition.state != AnimationState::Canceled)
}
/// Update our animations given a new style, canceling or starting new animations
/// when appropriate.
pub fn update_animations_for_new_style<E>(
&mut self,
element: E,
context: &SharedStyleContext,
new_style: &Arc<ComputedValues>,
resolver: &mut StyleResolverForElement<E>,
) where
E: TElement,
{
for animation in self.animations.iter_mut() {
if animation.is_cancelled_in_new_style(new_style) {
animation.state = AnimationState::Canceled;
}
}
maybe_start_animations(element, &context, &new_style, self, resolver);
}
/// Update our transitions given a new style, canceling or starting new animations
/// when appropriate.
pub fn update_transitions_for_new_style(
&mut self,
might_need_transitions_update: bool,
context: &SharedStyleContext,
old_style: Option<&Arc<ComputedValues>>,
after_change_style: &Arc<ComputedValues>,
) {
// If this is the first style, we don't trigger any transitions and we assume
// there were no previously triggered transitions.
let mut before_change_style = match old_style {
Some(old_style) => Arc::clone(old_style),
None => return,
};
// If the style of this element is display:none, then cancel all active transitions.
if after_change_style.get_box().clone_display().is_none() {
self.cancel_active_transitions();
return;
}
if !might_need_transitions_update {
return;
}
// We convert old values into `before-change-style` here.
if self.has_active_transition() || self.has_active_animation() {
self.apply_active_animations(context, &mut before_change_style);
}
let transitioning_properties = start_transitions_if_applicable(
context,
&before_change_style,
after_change_style,
self,
);
// Cancel any non-finished transitions that have properties which no longer transition.
for transition in self.transitions.iter_mut() {
if transition.state == AnimationState::Finished {
continue;
}
if transitioning_properties.contains(transition.property_animation.property_id()) {
continue;
}
transition.state = AnimationState::Canceled;
self.dirty = true;
}
}
fn start_transition_if_applicable(
&mut self,
context: &SharedStyleContext,
longhand_id: LonghandId,
index: usize,
old_style: &ComputedValues,
new_style: &Arc<ComputedValues>,
) {
let box_style = new_style.get_box();
let timing_function = box_style.transition_timing_function_mod(index);
let duration = box_style.transition_duration_mod(index);
let delay = box_style.transition_delay_mod(index).seconds() as f64;
let now = context.current_time_for_animations;
// Only start a new transition if the style actually changes between
// the old style and the new style.
let property_animation = match PropertyAnimation::from_longhand(
longhand_id,
timing_function,
duration,
old_style,
new_style,
) {
Some(property_animation) => property_animation,
None => return,
};
// Per [1], don't trigger a new transition if the end state for that
// transition is the same as that of a transition that's running or
// completed. We don't take into account any canceled animations.
// [1]: https://drafts.csswg.org/css-transitions/#starting
if self
.transitions
.iter()
.filter(|transition| transition.state != AnimationState::Canceled)
.any(|transition| transition.property_animation.to == property_animation.to)
{
return;
}
// We are going to start a new transition, but we might have to update
// it if we are replacing a reversed transition.
let reversing_adjusted_start_value = property_animation.from.clone();
let mut new_transition = Transition {
start_time: now + delay,
delay,
property_animation,
state: AnimationState::Pending,
is_new: true,
reversing_adjusted_start_value,
reversing_shortening_factor: 1.0,
};
if let Some(old_transition) = self
.transitions
.iter_mut()
.filter(|transition| transition.state == AnimationState::Running)
.find(|transition| transition.property_animation.property_id() == longhand_id)
{
// We always cancel any running transitions for the same property.
old_transition.state = AnimationState::Canceled;
new_transition.update_for_possibly_reversed_transition(old_transition, delay, now);
}
self.transitions.push(new_transition);
self.dirty = true;
}
/// Generate a `AnimationValueMap` for this `ElementAnimationSet`'s
/// active transitions at the given time value.
pub fn get_value_map_for_active_transitions(&self, now: f64) -> Option<AnimationValueMap> {
if !self.has_active_transition() {
return None;
}
let mut map =
AnimationValueMap::with_capacity_and_hasher(self.transitions.len(), Default::default());
for transition in &self.transitions {
if transition.state == AnimationState::Canceled {
continue;
}
let value = match transition.calculate_value(now) {
Some(value) => value,
None => continue,
};
map.insert(value.id(), value);
}
Some(map)
}
/// Generate a `AnimationValueMap` for this `ElementAnimationSet`'s
/// active animations at the given time value.
pub fn get_value_map_for_active_animations(&self, now: f64) -> Option<AnimationValueMap> {
if !self.has_active_animation() {
return None;
}
let mut map = Default::default();
for animation in &self.animations {
animation.get_property_declaration_at_time(now, &mut map);
}
Some(map)
}
}
#[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
/// A key that is used to identify nodes in the `DocumentAnimationSet`.
pub struct AnimationSetKey {
/// The node for this `AnimationSetKey`.
pub node: OpaqueNode,
/// The pseudo element for this `AnimationSetKey`. If `None` this key will
/// refer to the main content for its node.
pub pseudo_element: Option<PseudoElement>,
}
impl AnimationSetKey {
/// Create a new key given a node and optional pseudo element.
pub fn new(node: OpaqueNode, pseudo_element: Option<PseudoElement>) -> Self {
AnimationSetKey {
node,
pseudo_element,
}
}
/// Create a new key for the main content of this node.
pub fn new_for_non_pseudo(node: OpaqueNode) -> Self {
AnimationSetKey {
node,
pseudo_element: None,
}
}
/// Create a new key for given node and pseudo element.
pub fn new_for_pseudo(node: OpaqueNode, pseudo_element: PseudoElement) -> Self {
AnimationSetKey {
node,
pseudo_element: Some(pseudo_element),
}
}
}
#[derive(Clone, Debug, Default, MallocSizeOf)]
/// A set of animations for a document.
pub struct DocumentAnimationSet {
/// The `ElementAnimationSet`s that this set contains.
#[ignore_malloc_size_of = "Arc is hard"]
pub sets: Arc<RwLock<FxHashMap<AnimationSetKey, ElementAnimationSet>>>,
}
impl DocumentAnimationSet {
/// Return whether or not the provided node has active CSS animations.
pub fn has_active_animations(&self, key: &AnimationSetKey) -> bool {
self.sets
.read()
.get(key)
.map_or(false, |set| set.has_active_animation())
}
/// Return whether or not the provided node has active CSS transitions.
pub fn has_active_transitions(&self, key: &AnimationSetKey) -> bool {
self.sets
.read()
.get(key)
.map_or(false, |set| set.has_active_transition())
}
/// Return a locked PropertyDeclarationBlock with animation values for the given
/// key and time.
pub fn get_animation_declarations(
&self,
key: &AnimationSetKey,
time: f64,
shared_lock: &SharedRwLock,
) -> Option<Arc<Locked<PropertyDeclarationBlock>>> {
self.sets
.read()
.get(key)
.and_then(|set| set.get_value_map_for_active_animations(time))
.map(|map| {
let block = PropertyDeclarationBlock::from_animation_value_map(&map);
Arc::new(shared_lock.wrap(block))
})
}
/// Return a locked PropertyDeclarationBlock with transition values for the given
/// key and time.
pub fn get_transition_declarations(
&self,
key: &AnimationSetKey,
time: f64,
shared_lock: &SharedRwLock,
) -> Option<Arc<Locked<PropertyDeclarationBlock>>> {
self.sets
.read()
.get(key)
.and_then(|set| set.get_value_map_for_active_transitions(time))
.map(|map| {
let block = PropertyDeclarationBlock::from_animation_value_map(&map);
Arc::new(shared_lock.wrap(block))
})
}
/// Get all the animation declarations for the given key, returning an empty
/// `AnimationDeclarations` if there are no animations.
pub fn get_all_declarations(
&self,
key: &AnimationSetKey,
time: f64,
shared_lock: &SharedRwLock,
) -> AnimationDeclarations {
let sets = self.sets.read();
let set = match sets.get(key) {
Some(set) => set,
None => return Default::default(),
};
let animations = set.get_value_map_for_active_animations(time).map(|map| {
let block = PropertyDeclarationBlock::from_animation_value_map(&map);
Arc::new(shared_lock.wrap(block))
});
let transitions = set.get_value_map_for_active_transitions(time).map(|map| {
let block = PropertyDeclarationBlock::from_animation_value_map(&map);
Arc::new(shared_lock.wrap(block))
});
AnimationDeclarations {
animations,
transitions,
}
}
/// Cancel all animations for set at the given key.
pub fn cancel_all_animations_for_key(&self, key: &AnimationSetKey) {
if let Some(set) = self.sets.write().get_mut(key) {
set.cancel_all_animations();
}
}
}
/// Kick off any new transitions for this node and return all of the properties that are
/// transitioning. This is at the end of calculating style for a single node.
pub fn start_transitions_if_applicable(
context: &SharedStyleContext,
old_style: &ComputedValues,
new_style: &Arc<ComputedValues>,
animation_state: &mut ElementAnimationSet,
) -> LonghandIdSet {
let mut properties_that_transition = LonghandIdSet::new();
for transition in new_style.transition_properties() {
let physical_property = transition.longhand_id.to_physical(new_style.writing_mode);
if properties_that_transition.contains(physical_property) {
continue;
}
properties_that_transition.insert(physical_property);
animation_state.start_transition_if_applicable(
context,
physical_property,
transition.index,
old_style,
new_style,
);
}
properties_that_transition
}
/// Triggers animations for a given node looking at the animation property
/// values.
pub fn maybe_start_animations<E>(
element: E,
context: &SharedStyleContext,
new_style: &Arc<ComputedValues>,
animation_state: &mut ElementAnimationSet,
resolver: &mut StyleResolverForElement<E>,
) where
E: TElement,
{
let box_style = new_style.get_box();
for (i, name) in box_style.animation_name_iter().enumerate() {
let name = match name.as_atom() {
Some(atom) => atom,
None => continue,
};
debug!("maybe_start_animations: name={}", name);
let duration = box_style.animation_duration_mod(i).seconds() as f64;
if duration == 0. {
continue;
}
let keyframe_animation = match context.stylist.get_animation(name, element) {
Some(animation) => animation,
None => continue,
};
debug!("maybe_start_animations: animation {} found", name);
// If this animation doesn't have any keyframe, we can just continue
// without submitting it to the compositor, since both the first and
// the second keyframes would be synthetised from the computed
// values.
if keyframe_animation.steps.is_empty() {
continue;
}
// NB: This delay may be negative, meaning that the animation may be created
// in a state where we have advanced one or more iterations or even that the
// animation begins in a finished state.
let delay = box_style.animation_delay_mod(i).seconds();
let iteration_state = match box_style.animation_iteration_count_mod(i) {
AnimationIterationCount::Infinite => KeyframesIterationState::Infinite(0.0),
AnimationIterationCount::Number(n) => KeyframesIterationState::Finite(0.0, n.into()),
};
let animation_direction = box_style.animation_direction_mod(i);
let initial_direction = match animation_direction {
AnimationDirection::Normal | AnimationDirection::Alternate => {
AnimationDirection::Normal
},
AnimationDirection::Reverse | AnimationDirection::AlternateReverse => {
AnimationDirection::Reverse
},
};
let now = context.current_time_for_animations;
let started_at = now + delay as f64;
let mut starting_progress = (now - started_at) / duration;
let state = match box_style.animation_play_state_mod(i) {
AnimationPlayState::Paused => AnimationState::Paused(starting_progress),
AnimationPlayState::Running => AnimationState::Pending,
};
let computed_steps = ComputedKeyframe::generate_for_keyframes(
element,
&keyframe_animation,
context,
new_style,
new_style.get_box().animation_timing_function_mod(i),
resolver,
);
let mut new_animation = Animation {
name: name.clone(),
properties_changed: keyframe_animation.properties_changed,
computed_steps,
started_at,
duration,
fill_mode: box_style.animation_fill_mode_mod(i),
delay: delay as f64,
iteration_state,
state,
direction: animation_direction,
current_direction: initial_direction,
cascade_style: new_style.clone(),
is_new: true,
};
// If we started with a negative delay, make sure we iterate the animation if
// the delay moves us past the first iteration.
while starting_progress > 1. && !new_animation.on_last_iteration() {
new_animation.iterate();
starting_progress -= 1.;
}
animation_state.dirty = true;
// If the animation was already present in the list for the node, just update its state.
for existing_animation in animation_state.animations.iter_mut() {
if existing_animation.state == AnimationState::Canceled {
continue;
}
if new_animation.name == existing_animation.name {
existing_animation
.update_from_other(&new_animation, context.current_time_for_animations);
return;
}
}
animation_state.animations.push(new_animation);
}
}