C++ SVGAnimationElement::GetTimeContainer方法代码示例

void
nsSMILAnimationController::RewindElements()
{
  bool rewindNeeded = false;
  for (auto iter = mChildContainerTable.Iter(); !iter.Done(); iter.Next()) {
    nsSMILTimeContainer* container = iter.Get()->GetKey();
    if (container->NeedsRewind()) {
      rewindNeeded = true;
      break;
    }
  }

  if (!rewindNeeded)
    return;

  for (auto iter = mAnimationElementTable.Iter(); !iter.Done(); iter.Next()) {
    SVGAnimationElement* animElem = iter.Get()->GetKey();
    nsSMILTimeContainer* timeContainer = animElem->GetTimeContainer();
    if (timeContainer && timeContainer->NeedsRewind()) {
      animElem->TimedElement().Rewind();
    }
  }

  for (auto iter = mChildContainerTable.Iter(); !iter.Done(); iter.Next()) {
    iter.Get()->GetKey()->ClearNeedsRewind();
  }
}

/*static*/ PLDHashOperator
nsSMILAnimationController::RewindAnimation(AnimationElementPtrKey* aKey,
                                           void* aData)
{
  SVGAnimationElement* animElem = aKey->GetKey();
  nsSMILTimeContainer* timeContainer = animElem->GetTimeContainer();
  if (timeContainer && timeContainer->NeedsRewind()) {
    animElem->TimedElement().Rewind();
  }

  return PL_DHASH_NEXT;
}

void
nsSMILAnimationController::DoMilestoneSamples()
{
  // We need to sample the timing model but because SMIL operates independently
  // of the frame-rate, we can get one sample at t=0s and the next at t=10min.
  //
  // In between those two sample times a whole string of significant events
  // might be expected to take place: events firing, new interdependencies
  // between animations resolved and dissolved, etc.
  //
  // Furthermore, at any given time, we want to sample all the intervals that
  // end at that time BEFORE any that begin. This behaviour is implied by SMIL's
  // endpoint-exclusive timing model.
  //
  // So we have the animations (specifically the timed elements) register the
  // next significant moment (called a milestone) in their lifetime and then we
  // step through the model at each of these moments and sample those animations
  // registered for those times. This way events can fire in the correct order,
  // dependencies can be resolved etc.

  nsSMILTime sampleTime = INT64_MIN;

  while (true) {
    // We want to find any milestones AT OR BEFORE the current sample time so we
    // initialise the next milestone to the moment after (1ms after, to be
    // precise) the current sample time and see if there are any milestones
    // before that. Any other milestones will be dealt with in a subsequent
    // sample.
    nsSMILMilestone nextMilestone(GetCurrentTime() + 1, true);
    mChildContainerTable.EnumerateEntries(GetNextMilestone, &nextMilestone);

    if (nextMilestone.mTime > GetCurrentTime()) {
      break;
    }

    GetMilestoneElementsParams params;
    params.mMilestone = nextMilestone;
    mChildContainerTable.EnumerateEntries(GetMilestoneElements, &params);
    uint32_t length = params.mElements.Length();

    // During the course of a sampling we don't want to actually go backwards.
    // Due to negative offsets, early ends and the like, a timed element might
    // register a milestone that is actually in the past. That's fine, but it's
    // still only going to get *sampled* with whatever time we're up to and no
    // earlier.
    //
    // Because we're only performing this clamping at the last moment, the
    // animations will still all get sampled in the correct order and
    // dependencies will be appropriately resolved.
    sampleTime = std::max(nextMilestone.mTime, sampleTime);

    for (uint32_t i = 0; i < length; ++i) {
      SVGAnimationElement* elem = params.mElements[i].get();
      NS_ABORT_IF_FALSE(elem, "nullptr animation element in list");
      nsSMILTimeContainer* container = elem->GetTimeContainer();
      if (!container)
        // The container may be nullptr if the element has been detached from its
        // parent since registering a milestone.
        continue;

      nsSMILTimeValue containerTimeValue =
        container->ParentToContainerTime(sampleTime);
      if (!containerTimeValue.IsDefinite())
        continue;

      // Clamp the converted container time to non-negative values.
      nsSMILTime containerTime = std::max<nsSMILTime>(0, containerTimeValue.GetMillis());

      if (nextMilestone.mIsEnd) {
        elem->TimedElement().SampleEndAt(containerTime);
      } else {
        elem->TimedElement().SampleAt(containerTime);
      }
    }
  }
}