C++ Animation::SetEffect方法代码示例

// https://w3c.github.io/web-animations/#setting-the-target-effect
void
Animation::SetEffectNoUpdate(AnimationEffectReadOnly* aEffect)
{
  RefPtr<Animation> kungFuDeathGrip(this);

  if (mEffect == aEffect) {
    return;
  }

  AutoMutationBatchForAnimation mb(*this);
  bool wasRelevant = mIsRelevant;

  if (mEffect) {
    if (!aEffect) {
      // If the new effect is null, call ResetPendingTasks before clearing
      // mEffect since ResetPendingTasks needs it to get the appropriate
      // PendingAnimationTracker.
      ResetPendingTasks();
    }

    // We need to notify observers now because once we set mEffect to null
    // we won't be able to find the target element to notify.
    if (mIsRelevant) {
      nsNodeUtils::AnimationRemoved(this);
    }

    // Break links with the old effect and then drop it.
    RefPtr<AnimationEffectReadOnly> oldEffect = mEffect;
    mEffect = nullptr;
    oldEffect->SetAnimation(nullptr);

    // The following will not do any notification because mEffect is null.
    UpdateRelevance();
  }

  if (aEffect) {
    // Break links from the new effect to its previous animation, if any.
    RefPtr<AnimationEffectReadOnly> newEffect = aEffect;
    Animation* prevAnim = aEffect->GetAnimation();
    if (prevAnim) {
      prevAnim->SetEffect(nullptr);
    }

    // Create links with the new effect. SetAnimation(this) will also update
    // mIsRelevant of this animation, and then notify mutation observer if
    // needed by calling Animation::UpdateRelevance(), so we don't need to
    // call it again.
    mEffect = newEffect;
    mEffect->SetAnimation(this);

    // Notify possible add or change.
    // If the target is different, the change notification will be ignored by
    // AutoMutationBatchForAnimation.
    if (wasRelevant && mIsRelevant) {
      nsNodeUtils::AnimationChanged(this);
    }

    // Reschedule pending pause or pending play tasks.
    // If we have a pending animation, it will either be registered
    // in the pending animation tracker and have a null pending ready time,
    // or, after it has been painted, it will be removed from the tracker
    // and assigned a pending ready time.
    // After updating the effect we'll typically need to repaint so if we've
    // already been assigned a pending ready time, we should clear it and put
    // the animation back in the tracker.
    if (!mPendingReadyTime.IsNull()) {
      mPendingReadyTime.SetNull();

      nsIDocument* doc = GetRenderedDocument();
      if (doc) {
        PendingAnimationTracker* tracker =
          doc->GetOrCreatePendingAnimationTracker();
        if (mPendingState == PendingState::PlayPending) {
          tracker->AddPlayPending(*this);
        } else {
          tracker->AddPausePending(*this);
        }
      }
    }
  }

  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
}