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

/*
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#include "platform/scroll/ScrollAnimatorBase.h"

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

namespace blink {

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

ScrollAnimatorBase::~ScrollAnimatorBase()
{
}

FloatSize ScrollAnimatorBase::computeDeltaToConsume(const FloatSize& delta) const
{
    FloatPoint newPos = toFloatPoint(m_scrollableArea->clampScrollPosition(m_currentPos + delta));
    return newPos - m_currentPos;
}

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

    m_currentPos = newPos;

    notifyPositionChanged();

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

void ScrollAnimatorBase::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
{
    m_currentPos = offset;
    notifyPositionChanged();
}

void ScrollAnimatorBase::setCurrentPosition(const FloatPoint& position)
{
    m_currentPos = position;
}

FloatPoint ScrollAnimatorBase::currentPosition() const
{
    return m_currentPos;
}

void ScrollAnimatorBase::notifyPositionChanged()
{
    m_scrollableArea->scrollPositionChanged(m_currentPos, UserScroll);
}

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

} // namespace blink