third_party/WebKit/Source/platform/scroll/ScrollAnimatorBase.cpp

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#include "platform/scroll/ScrollAnimatorBase.h"

#include "platform/RuntimeEnabledFeatures.h"
#include "platform/scroll/ScrollableArea.h"
#include "wtf/MathExtras.h"

namespace blink {

ScrollAnimatorBase::ScrollAnimatorBase(ScrollableArea* scrollableArea)
    : m_scrollableArea(scrollableArea) {}

ScrollAnimatorBase::~ScrollAnimatorBase() {}

ScrollOffset ScrollAnimatorBase::computeDeltaToConsume(
    const ScrollOffset& delta) const {
  ScrollOffset newPos =
      m_scrollableArea->clampScrollOffset(m_currentOffset + delta);
  return newPos - m_currentOffset;
}

ScrollResult ScrollAnimatorBase::userScroll(ScrollGranularity,
                                            const ScrollOffset& delta) {
  ScrollOffset consumedDelta = computeDeltaToConsume(delta);
  ScrollOffset newPos = m_currentOffset + consumedDelta;
  if (m_currentOffset == newPos)
    return ScrollResult(false, false, delta.width(), delta.height());

  m_currentOffset = newPos;

  notifyOffsetChanged();

  return ScrollResult(consumedDelta.width(), consumedDelta.height(),
                      delta.width() - consumedDelta.width(),
                      delta.height() - consumedDelta.height());
}

void ScrollAnimatorBase::scrollToOffsetWithoutAnimation(
    const ScrollOffset& offset) {
  m_currentOffset = offset;
  notifyOffsetChanged();
}

void ScrollAnimatorBase::setCurrentOffset(const ScrollOffset& offset) {
  m_currentOffset = offset;
}

ScrollOffset ScrollAnimatorBase::currentOffset() const {
  return m_currentOffset;
}

void ScrollAnimatorBase::notifyOffsetChanged() {
  scrollOffsetChanged(m_currentOffset, UserScroll);
}

DEFINE_TRACE(ScrollAnimatorBase) {
  visitor->trace(m_scrollableArea);
  ScrollAnimatorCompositorCoordinator::trace(visitor);
}

}  // namespace blink