Source/WebCore/platform/ScrollAnimator.cpp

/*
 * Copyright (c) 2010, Google Inc. All rights reserved.
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 * in the documentation and/or other materials provided with the
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 * 
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#include "config.h"
#include "ScrollAnimator.h"

#include "FloatPoint.h"
#include "ScrollbarClient.h"
#include <algorithm>

namespace WebCore {

#if !ENABLE(SMOOTH_SCROLLING)
ScrollAnimator* ScrollAnimator::create(ScrollbarClient* client)
{
    return new ScrollAnimator(client);
}
#endif

ScrollAnimator::ScrollAnimator(ScrollbarClient* client)
    : m_client(client)
    , m_currentPosX(0)
    , m_currentPosY(0)
{
}

ScrollAnimator::~ScrollAnimator()
{
}

bool ScrollAnimator::scroll(ScrollbarOrientation orientation, ScrollGranularity, float step, float multiplier)
{
    float* currentPos = (orientation == HorizontalScrollbar) ? &m_currentPosX : &m_currentPosY;
    float newPos = std::max(std::min(*currentPos + (step * multiplier), static_cast<float>(m_client->scrollSize(orientation))), 0.0f);
    if (*currentPos == newPos)
        return false;
    *currentPos = newPos;

    notityPositionChanged();

    return true;
}

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

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

void ScrollAnimator::notityPositionChanged()
{
    m_client->setScrollOffsetFromAnimation(IntPoint(m_currentPosX, m_currentPosY));
}

} // namespace WebCore