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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 */
#ifndef mozilla_EffectCompositor_h
#define mozilla_EffectCompositor_h
#include "mozilla/AnimationPerformanceWarning.h"
#include "mozilla/AnimationTarget.h"
#include "mozilla/EnumeratedArray.h"
#include "mozilla/HashTable.h"
#include "mozilla/Maybe.h"
#include "mozilla/OwningNonNull.h"
#include "mozilla/PseudoElementHashEntry.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ServoTypes.h"
#include "nsCSSPropertyID.h"
#include "nsCycleCollectionParticipant.h"
#include "nsTHashMap.h"
#include "nsTArray.h"
class nsCSSPropertyIDSet;
class nsAtom;
class nsIFrame;
class nsPresContext;
enum class DisplayItemType : uint8_t;
namespace mozilla {
class ComputedStyle;
class EffectSet;
class RestyleTracker;
struct StyleAnimationValue;
struct StyleAnimationValueMap;
struct AnimationProperty;
struct NonOwningAnimationTarget;
namespace dom {
class Animation;
class Element;
class KeyframeEffect;
} // namespace dom
class EffectCompositor {
explicit EffectCompositor(nsPresContext* aPresContext)
: mPresContext(aPresContext) {}
void Disconnect() { mPresContext = nullptr; }
// Animations can be applied at two different levels in the CSS cascade:
enum class CascadeLevel : uint32_t {
// The animations sheet (CSS animations, script-generated animations,
// and CSS transitions that are no longer tied to CSS markup)
Animations = 0,
// The transitions sheet (CSS transitions that are tied to CSS markup)
Transitions = 1
// We don't define this as part of CascadeLevel as then we'd have to add
// explicit checks for the Count enum value everywhere CascadeLevel is used.
static const size_t kCascadeLevelCount =
static_cast<size_t>(CascadeLevel::Transitions) + 1;
// NOTE: This can return null after Disconnect().
nsPresContext* PresContext() const { return mPresContext; }
enum class RestyleType {
// Animation style has changed but the compositor is applying the same
// change so we might be able to defer updating the main thread until it
// becomes necessary.
// Animation style has changed and needs to be updated on the main thread.
// Animation style has changed and needs to be updated on the main thread
// as well as forcing animations on layers to be updated.
// This is needed in cases such as when an animation becomes paused or has
// its playback rate changed. In such cases, although the computed style
// and refresh driver time might not change, we still need to ensure the
// corresponding animations on layers are updated to reflect the new
// configuration of the animation.
// Notifies the compositor that the animation rule for the specified
// (pseudo-)element at the specified cascade level needs to be updated.
// The specified steps taken to update the animation rule depend on
// |aRestyleType| whose values are described above.
void RequestRestyle(dom::Element* aElement, PseudoStyleType aPseudoType,
RestyleType aRestyleType, CascadeLevel aCascadeLevel);
// Schedule an animation restyle. This is called automatically by
// RequestRestyle when necessary. However, it is exposed here since we also
// need to perform this step when triggering transitions *without* also
// invalidating the animation style rule (which RequestRestyle would do).
void PostRestyleForAnimation(dom::Element* aElement,
PseudoStyleType aPseudoType,
CascadeLevel aCascadeLevel);
// Posts an animation restyle for any elements whose animation style rule
// is out of date but for which an animation restyle has not yet been
// posted because updates on the main thread are throttled.
void PostRestyleForThrottledAnimations();
// Clear all pending restyle requests for the given (pseudo-) element (and its
// ::before, ::after and ::marker elements if the given element is not
// pseudo).
void ClearRestyleRequestsFor(dom::Element* aElement);
// Called when computed style on the specified (pseudo-) element might
// have changed so that any context-sensitive values stored within
// animation effects (e.g. em-based endpoints used in keyframe effects)
// can be re-resolved to computed values.
void UpdateEffectProperties(const ComputedStyle* aStyle,
dom::Element* aElement,
PseudoStyleType aPseudoType);
// Get the animation rule for the appropriate level of the cascade for
// a (pseudo-)element. Called from the Servo side.
// The animation rule is stored in |StyleAnimationValueMap|.
// We need to be careful while doing any modification because it may cause
// some thread-safe issues.
bool GetServoAnimationRule(const dom::Element* aElement,
PseudoStyleType aPseudoType,
CascadeLevel aCascadeLevel,
StyleAnimationValueMap* aAnimationValues);
// A variant on GetServoAnimationRule that composes all the effects for an
// element up to and including |aEffect|.
// Note that |aEffect| might not be in the EffectSet since we can use this for
// committing the computed style of a removed Animation.
bool ComposeServoAnimationRuleForEffect(
dom::KeyframeEffect& aEffect, CascadeLevel aCascadeLevel,
StyleAnimationValueMap* aAnimationValues);
bool HasPendingStyleUpdates() const;
static bool HasAnimationsForCompositor(const nsIFrame* aFrame,
DisplayItemType aType);
static nsTArray<RefPtr<dom::Animation>> GetAnimationsForCompositor(
const nsIFrame* aFrame, const nsCSSPropertyIDSet& aPropertySet);
static void ClearIsRunningOnCompositor(const nsIFrame* aFrame,
DisplayItemType aType);
// Update animation cascade results for the specified (pseudo-)element
// but only if we have marked the cascade as needing an update due a
// the change in the set of effects or a change in one of the effects'
// "in effect" state.
// This method does NOT detect if other styles that apply above the
// animation level of the cascade have changed.
static void MaybeUpdateCascadeResults(dom::Element* aElement,
PseudoStyleType aPseudoType);
// Update the mPropertiesWithImportantRules and
// mPropertiesForAnimationsLevel members of the given EffectSet, and also
// request any restyles required by changes to the cascade result.
// NOTE: This can be expensive so we should only call it if styles that apply
// above the animation level of the cascade might have changed. For all
// other cases we should call MaybeUpdateCascadeResults.
// This is typically reserved for internal callers but is public here since
// when we detect changes to the cascade on the Servo side we can't call
// MarkCascadeNeedsUpdate during the traversal so instead we call this as part
// of a follow-up sequential task.
static void UpdateCascadeResults(EffectSet& aEffectSet,
dom::Element* aElement,
PseudoStyleType aPseudoType);
// Helper to fetch the corresponding element and pseudo-type from a frame.
// For frames corresponding to pseudo-elements, the returned element is the
// element on which we store the animations (i.e. the EffectSet and/or
// AnimationCollection), *not* the generated content.
// For display:table content, which maintains a distinction between primary
// frame (table wrapper frame) and style frame (inner table frame), animations
// are stored on the content associated with the _style_ frame even though
// some (particularly transform-like animations) may be applied to the
// _primary_ frame. As a result, callers will typically want to pass the style
// frame to this function.
// Returns an empty result when a suitable element cannot be found including
// when the frame represents a pseudo-element on which we do not support
// animations.
static Maybe<NonOwningAnimationTarget> GetAnimationElementAndPseudoForFrame(
const nsIFrame* aFrame);
// Associates a performance warning with effects on |aFrame| that animate
// properties in |aPropertySet|.
static void SetPerformanceWarning(
const nsIFrame* aFrame, const nsCSSPropertyIDSet& aPropertySet,
const AnimationPerformanceWarning& aWarning);
// Do a bunch of stuff that we should avoid doing during the parallel
// traversal (e.g. changing member variables) for all elements that we expect
// to restyle on the next traversal.
// Returns true if there are elements needing a restyle for animation.
bool PreTraverse(ServoTraversalFlags aFlags);
// Similar to the above but for all elements in the subtree rooted
// at aElement.
bool PreTraverseInSubtree(ServoTraversalFlags aFlags, dom::Element* aRoot);
// Record a (pseudo-)element that may have animations that can be removed.
void NoteElementForReducing(const NonOwningAnimationTarget& aTarget);
bool NeedsReducing() const { return !mElementsToReduce.empty(); }
void ReduceAnimations();
// Returns true if any type of compositor animations on |aFrame| allow
// runnning on the compositor.
// Sets the reason in |aWarning| if the result is false.
static bool AllowCompositorAnimationsOnFrame(
const nsIFrame* aFrame,
AnimationPerformanceWarning::Type& aWarning /* out */);
~EffectCompositor() = default;
// Get the properties in |aEffectSet| that we are able to animate on the
// compositor but which are also specified at a higher level in the cascade
// than the animations level.
static nsCSSPropertyIDSet GetOverriddenProperties(
EffectSet& aEffectSet, dom::Element* aElement,
PseudoStyleType aPseudoType);
static nsPresContext* GetPresContext(dom::Element* aElement);
nsPresContext* mPresContext;
// Elements with a pending animation restyle. The associated bool value is
// true if a pending animation restyle has also been dispatched. For
// animations that can be throttled, we will add an entry to the hashtable to
// indicate that the style rule on the element is out of date but without
// posting a restyle to update it.
EnumeratedArray<CascadeLevel, CascadeLevel(kCascadeLevelCount),
nsTHashMap<PseudoElementHashEntry, bool>>
bool mIsInPreTraverse = false;
HashSet<OwningAnimationTarget> mElementsToReduce;
} // namespace mozilla
#endif // mozilla_EffectCompositor_h