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

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

#include "platform/RuntimeEnabledFeatures.h"
#include "platform/geometry/FloatPoint.h"
#include "platform/scroll/ScrollableArea.h"
#include "wtf/PassOwnPtr.h"
#include <algorithm>

namespace blink {

ScrollAnimatorBase::ScrollAnimatorBase(ScrollableArea* scrollableArea)
    : m_scrollableArea(scrollableArea)
    , m_currentPosX(0)
    , m_currentPosY(0)
{
}

ScrollAnimatorBase::~ScrollAnimatorBase()
{
}

ScrollResultOneDimensional ScrollAnimatorBase::userScroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float delta)
{
    float& currentPos = (orientation == HorizontalScrollbar) ? m_currentPosX : m_currentPosY;
    float newPos = clampScrollPosition(orientation, currentPos + step * delta);
    if (currentPos == newPos)
        return ScrollResultOneDimensional(false, delta);

    float usedDelta = (newPos - currentPos) / step;
    currentPos = newPos;

    notifyPositionChanged();

    return ScrollResultOneDimensional(true, delta - usedDelta);
}

void ScrollAnimatorBase::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
{
    m_currentPosX = offset.x();
    m_currentPosY = offset.y();
    notifyPositionChanged();
}

void ScrollAnimatorBase::setCurrentPosition(const FloatPoint& position)
{
    m_currentPosX = position.x();
    m_currentPosY = position.y();
}

FloatPoint ScrollAnimatorBase::currentPosition() const
{
    return FloatPoint(m_currentPosX, m_currentPosY);
}

void ScrollAnimatorBase::notifyPositionChanged()
{
    m_scrollableArea->scrollPositionChanged(DoublePoint(m_currentPosX, m_currentPosY), UserScroll);
}

float ScrollAnimatorBase::clampScrollPosition(ScrollbarOrientation orientation, float pos)
{
    float maxScrollPos = m_scrollableArea->maximumScrollPosition(orientation);
    float minScrollPos = m_scrollableArea->minimumScrollPosition(orientation);
    return std::max(std::min(pos, maxScrollPos), minScrollPos);
}

} // namespace blink