Source/core/page/scrolling/ScrollingConstraints.cpp

/*
 * Copyright (C) 2012 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "core/page/scrolling/ScrollingConstraints.h"

namespace blink {

FloatPoint FixedPositionViewportConstraints::layerPositionForViewportRect(const FloatRect& viewportRect) const
{
    FloatSize offset;

    if (hasAnchorEdge(AnchorEdgeLeft))
        offset.setWidth(viewportRect.x() - m_viewportRectAtLastLayout.x());
    else if (hasAnchorEdge(AnchorEdgeRight))
        offset.setWidth(viewportRect.maxX() - m_viewportRectAtLastLayout.maxX());

    if (hasAnchorEdge(AnchorEdgeTop))
        offset.setHeight(viewportRect.y() - m_viewportRectAtLastLayout.y());
    else if (hasAnchorEdge(AnchorEdgeBottom))
        offset.setHeight(viewportRect.maxY() - m_viewportRectAtLastLayout.maxY());

    return m_layerPositionAtLastLayout + offset;
}

} // namespace blink