gecko-dev/dom/animation/AnimationEffect.cpp

/* -*- 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 http://mozilla.org/MPL/2.0/. */

#include "mozilla/dom/AnimationEffect.h"
#include "mozilla/dom/AnimationEffectBinding.h"

#include "mozilla/dom/Animation.h"
#include "mozilla/dom/KeyframeEffect.h"
#include "mozilla/dom/MutationObservers.h"
#include "mozilla/AnimationUtils.h"
#include "mozilla/FloatingPoint.h"
#include "nsDOMMutationObserver.h"

namespace mozilla::dom {

NS_IMPL_CYCLE_COLLECTION_CLASS(AnimationEffect)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AnimationEffect)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument, mAnimation)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AnimationEffect)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument, mAnimation)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(AnimationEffect)

NS_IMPL_CYCLE_COLLECTING_ADDREF(AnimationEffect)
NS_IMPL_CYCLE_COLLECTING_RELEASE(AnimationEffect)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AnimationEffect)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

AnimationEffect::AnimationEffect(Document* aDocument, TimingParams&& aTiming)
    : mDocument(aDocument), mTiming(std::move(aTiming)) {}

AnimationEffect::~AnimationEffect() = default;

nsISupports* AnimationEffect::GetParentObject() const {
  return ToSupports(mDocument);
}

// https://drafts.csswg.org/web-animations/#current
bool AnimationEffect::IsCurrent() const {
  if (!mAnimation || mAnimation->PlayState() == AnimationPlayState::Finished) {
    return false;
  }

  ComputedTiming computedTiming = GetComputedTiming();
  if (computedTiming.mPhase == ComputedTiming::AnimationPhase::Active) {
    return true;
  }

  return (mAnimation->PlaybackRate() > 0 &&
          computedTiming.mPhase == ComputedTiming::AnimationPhase::Before) ||
         (mAnimation->PlaybackRate() < 0 &&
          computedTiming.mPhase == ComputedTiming::AnimationPhase::After);
}

// https://drafts.csswg.org/web-animations/#in-effect
bool AnimationEffect::IsInEffect() const {
  ComputedTiming computedTiming = GetComputedTiming();
  return !computedTiming.mProgress.IsNull();
}

void AnimationEffect::SetSpecifiedTiming(TimingParams&& aTiming) {
  if (mTiming == aTiming) {
    return;
  }

  mTiming = aTiming;

  if (mAnimation) {
    Maybe<nsAutoAnimationMutationBatch> mb;
    if (AsKeyframeEffect() && AsKeyframeEffect()->GetAnimationTarget()) {
      mb.emplace(AsKeyframeEffect()->GetAnimationTarget().mElement->OwnerDoc());
    }

    mAnimation->NotifyEffectTimingUpdated();

    if (mAnimation->IsRelevant()) {
      MutationObservers::NotifyAnimationChanged(mAnimation);
    }

    if (AsKeyframeEffect()) {
      AsKeyframeEffect()->RequestRestyle(EffectCompositor::RestyleType::Layer);
    }
  }
  // For keyframe effects, NotifyEffectTimingUpdated above will eventually
  // cause KeyframeEffect::NotifyAnimationTimingUpdated to be called so it can
  // update its registration with the target element as necessary.
}

ComputedTiming AnimationEffect::GetComputedTimingAt(
    const Nullable<TimeDuration>& aLocalTime, const TimingParams& aTiming,
    double aPlaybackRate) {
  static const StickyTimeDuration zeroDuration;

  // Always return the same object to benefit from return-value optimization.
  ComputedTiming result;

  if (aTiming.Duration()) {
    MOZ_ASSERT(aTiming.Duration().ref() >= zeroDuration,
               "Iteration duration should be positive");
    result.mDuration = aTiming.Duration().ref();
  }

  MOZ_ASSERT(aTiming.Iterations() >= 0.0 && !IsNaN(aTiming.Iterations()),
             "mIterations should be nonnegative & finite, as ensured by "
             "ValidateIterations or CSSParser");
  result.mIterations = aTiming.Iterations();

  MOZ_ASSERT(aTiming.IterationStart() >= 0.0,
             "mIterationStart should be nonnegative, as ensured by "
             "ValidateIterationStart");
  result.mIterationStart = aTiming.IterationStart();

  result.mActiveDuration = aTiming.ActiveDuration();
  result.mEndTime = aTiming.EndTime();
  result.mFill = aTiming.Fill() == dom::FillMode::Auto ? dom::FillMode::None
                                                       : aTiming.Fill();

  // The default constructor for ComputedTiming sets all other members to
  // values consistent with an animation that has not been sampled.
  if (aLocalTime.IsNull()) {
    return result;
  }
  const TimeDuration& localTime = aLocalTime.Value();

  StickyTimeDuration beforeActiveBoundary =
      std::max(std::min(StickyTimeDuration(aTiming.Delay()), result.mEndTime),
               zeroDuration);

  StickyTimeDuration activeAfterBoundary = std::max(
      std::min(StickyTimeDuration(aTiming.Delay() + result.mActiveDuration),
               result.mEndTime),
      zeroDuration);

  if (localTime > activeAfterBoundary ||
      (aPlaybackRate >= 0 && localTime == activeAfterBoundary)) {
    result.mPhase = ComputedTiming::AnimationPhase::After;
    if (!result.FillsForwards()) {
      // The animation isn't active or filling at this time.
      return result;
    }
    result.mActiveTime =
        std::max(std::min(StickyTimeDuration(localTime - aTiming.Delay()),
                          result.mActiveDuration),
                 zeroDuration);
  } else if (localTime < beforeActiveBoundary ||
             (aPlaybackRate < 0 && localTime == beforeActiveBoundary)) {
    result.mPhase = ComputedTiming::AnimationPhase::Before;
    if (!result.FillsBackwards()) {
      // The animation isn't active or filling at this time.
      return result;
    }
    result.mActiveTime =
        std::max(StickyTimeDuration(localTime - aTiming.Delay()), zeroDuration);
  } else {
    MOZ_ASSERT(result.mActiveDuration,
               "How can we be in the middle of a zero-duration interval?");
    result.mPhase = ComputedTiming::AnimationPhase::Active;
    result.mActiveTime = localTime - aTiming.Delay();
  }

  // Convert active time to a multiple of iterations.
  // https://drafts.csswg.org/web-animations/#overall-progress
  double overallProgress;
  if (!result.mDuration) {
    overallProgress = result.mPhase == ComputedTiming::AnimationPhase::Before
                          ? 0.0
                          : result.mIterations;
  } else {
    overallProgress = result.mActiveTime / result.mDuration;
  }

  // Factor in iteration start offset.
  if (IsFinite(overallProgress)) {
    overallProgress += result.mIterationStart;
  }

  // Determine the 0-based index of the current iteration.
  // https://drafts.csswg.org/web-animations/#current-iteration
  result.mCurrentIteration =
      (result.mIterations >= double(UINT64_MAX) &&
       result.mPhase == ComputedTiming::AnimationPhase::After) ||
              overallProgress >= double(UINT64_MAX)
          ? UINT64_MAX  // In GetComputedTimingDictionary(),
                        // we will convert this into Infinity
          : static_cast<uint64_t>(overallProgress);

  // Convert the overall progress to a fraction of a single iteration--the
  // simply iteration progress.
  // https://drafts.csswg.org/web-animations/#simple-iteration-progress
  double progress = IsFinite(overallProgress)
                        ? fmod(overallProgress, 1.0)
                        : fmod(result.mIterationStart, 1.0);

  // When we are at the end of the active interval and the end of an iteration
  // we need to report the end of the final iteration and not the start of the
  // next iteration. We *don't* want to do this, however, when we have
  // a zero-iteration animation.
  if (progress == 0.0 &&
      (result.mPhase == ComputedTiming::AnimationPhase::After ||
       result.mPhase == ComputedTiming::AnimationPhase::Active) &&
      result.mActiveTime == result.mActiveDuration &&
      result.mIterations != 0.0) {
    // The only way we can reach the end of the active interval and have
    // a progress of zero and a current iteration of zero, is if we have a
    // zero iteration count -- something we should have detected above.
    MOZ_ASSERT(result.mCurrentIteration != 0,
               "Should not have zero current iteration");
    progress = 1.0;
    if (result.mCurrentIteration != UINT64_MAX) {
      result.mCurrentIteration--;
    }
  }

  // Factor in the direction.
  bool thisIterationReverse = false;
  switch (aTiming.Direction()) {
    case PlaybackDirection::Normal:
      thisIterationReverse = false;
      break;
    case PlaybackDirection::Reverse:
      thisIterationReverse = true;
      break;
    case PlaybackDirection::Alternate:
      thisIterationReverse = (result.mCurrentIteration & 1) == 1;
      break;
    case PlaybackDirection::Alternate_reverse:
      thisIterationReverse = (result.mCurrentIteration & 1) == 0;
      break;
    default:
      MOZ_ASSERT_UNREACHABLE("Unknown PlaybackDirection type");
  }
  if (thisIterationReverse) {
    progress = 1.0 - progress;
  }

  // Calculate the 'before flag' which we use when applying step timing
  // functions.
  if ((result.mPhase == ComputedTiming::AnimationPhase::After &&
       thisIterationReverse) ||
      (result.mPhase == ComputedTiming::AnimationPhase::Before &&
       !thisIterationReverse)) {
    result.mBeforeFlag = ComputedTimingFunction::BeforeFlag::Set;
  }

  // Apply the easing.
  if (aTiming.TimingFunction()) {
    progress = aTiming.TimingFunction()->GetValue(progress, result.mBeforeFlag);
  }

  MOZ_ASSERT(IsFinite(progress), "Progress value should be finite");
  result.mProgress.SetValue(progress);
  return result;
}

ComputedTiming AnimationEffect::GetComputedTiming(
    const TimingParams* aTiming) const {
  double playbackRate = mAnimation ? mAnimation->PlaybackRate() : 1;
  return GetComputedTimingAt(
      GetLocalTime(), aTiming ? *aTiming : SpecifiedTiming(), playbackRate);
}

// Helper function for generating an (Computed)EffectTiming dictionary
static void GetEffectTimingDictionary(const TimingParams& aTiming,
                                      EffectTiming& aRetVal) {
  aRetVal.mDelay = aTiming.Delay().ToMilliseconds();
  aRetVal.mEndDelay = aTiming.EndDelay().ToMilliseconds();
  aRetVal.mFill = aTiming.Fill();
  aRetVal.mIterationStart = aTiming.IterationStart();
  aRetVal.mIterations = aTiming.Iterations();
  if (aTiming.Duration()) {
    aRetVal.mDuration.SetAsUnrestrictedDouble() =
        aTiming.Duration()->ToMilliseconds();
  }
  aRetVal.mDirection = aTiming.Direction();
  if (aTiming.TimingFunction()) {
    aRetVal.mEasing.Truncate();
    aTiming.TimingFunction()->AppendToString(aRetVal.mEasing);
  }
}

void AnimationEffect::GetTiming(EffectTiming& aRetVal) const {
  GetEffectTimingDictionary(SpecifiedTiming(), aRetVal);
}

void AnimationEffect::GetComputedTimingAsDict(
    ComputedEffectTiming& aRetVal) const {
  // Specified timing
  GetEffectTimingDictionary(SpecifiedTiming(), aRetVal);

  // Computed timing
  double playbackRate = mAnimation ? mAnimation->PlaybackRate() : 1;
  const Nullable<TimeDuration> currentTime = GetLocalTime();
  ComputedTiming computedTiming =
      GetComputedTimingAt(currentTime, SpecifiedTiming(), playbackRate);

  aRetVal.mDuration.SetAsUnrestrictedDouble() =
      computedTiming.mDuration.ToMilliseconds();
  aRetVal.mFill = computedTiming.mFill;
  aRetVal.mActiveDuration = computedTiming.mActiveDuration.ToMilliseconds();
  aRetVal.mEndTime = computedTiming.mEndTime.ToMilliseconds();
  aRetVal.mLocalTime = AnimationUtils::TimeDurationToDouble(currentTime);
  aRetVal.mProgress = computedTiming.mProgress;

  if (!aRetVal.mProgress.IsNull()) {
    // Convert the returned currentIteration into Infinity if we set
    // (uint64_t) computedTiming.mCurrentIteration to UINT64_MAX
    double iteration =
        computedTiming.mCurrentIteration == UINT64_MAX
            ? PositiveInfinity<double>()
            : static_cast<double>(computedTiming.mCurrentIteration);
    aRetVal.mCurrentIteration.SetValue(iteration);
  }
}

void AnimationEffect::UpdateTiming(const OptionalEffectTiming& aTiming,
                                   ErrorResult& aRv) {
  TimingParams timing =
      TimingParams::MergeOptionalEffectTiming(mTiming, aTiming, aRv);
  if (aRv.Failed()) {
    return;
  }

  SetSpecifiedTiming(std::move(timing));
}

Nullable<TimeDuration> AnimationEffect::GetLocalTime() const {
  // Since the *animation* start time is currently always zero, the local
  // time is equal to the parent time.
  Nullable<TimeDuration> result;
  if (mAnimation) {
    result = mAnimation->GetCurrentTimeAsDuration();
  }
  return result;
}

}  // namespace mozilla::dom