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/*
* 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 "ScrollingConstraints.h"
namespace WebCore {
FloatSize StickyPositionViewportConstraints::computeStickyOffset(const FloatRect& viewportRect) const
{
FloatRect boxRect = m_absoluteStickyBoxRect;
if (hasAnchorEdge(AnchorEdgeRight)) {
float rightLimit = viewportRect.maxX() - m_rightOffset;
float rightDelta = std::min<float>(0, rightLimit - m_absoluteStickyBoxRect.maxX());
float availableSpace = std::min<float>(0, m_absoluteContainingBlockRect.x() - m_absoluteStickyBoxRect.x());
if (rightDelta < availableSpace)
rightDelta = availableSpace;
boxRect.move(rightDelta, 0);
}
if (hasAnchorEdge(AnchorEdgeLeft)) {
float leftLimit = viewportRect.x() + m_leftOffset;
float leftDelta = std::max<float>(0, leftLimit - m_absoluteStickyBoxRect.x());
float availableSpace = std::max<float>(0, m_absoluteContainingBlockRect.maxX() - m_absoluteStickyBoxRect.maxX());
if (leftDelta > availableSpace)
leftDelta = availableSpace;
boxRect.move(leftDelta, 0);
}
if (hasAnchorEdge(AnchorEdgeBottom)) {
float bottomLimit = viewportRect.maxY() - m_bottomOffset;
float bottomDelta = std::min<float>(0, bottomLimit - m_absoluteStickyBoxRect.maxY());
float availableSpace = std::min<float>(0, m_absoluteContainingBlockRect.y() - m_absoluteStickyBoxRect.y());
if (bottomDelta < availableSpace)
bottomDelta = availableSpace;
boxRect.move(0, bottomDelta);
}
if (hasAnchorEdge(AnchorEdgeTop)) {
float topLimit = viewportRect.y() + m_topOffset;
float topDelta = std::max<float>(0, topLimit - m_absoluteStickyBoxRect.y());
float availableSpace = std::max<float>(0, m_absoluteContainingBlockRect.maxY() - m_absoluteStickyBoxRect.maxY());
if (topDelta > availableSpace)
topDelta = availableSpace;
boxRect.move(0, topDelta);
}
return boxRect.location() - m_absoluteStickyBoxRect.location();
}
FloatPoint StickyPositionViewportConstraints::layerPositionForViewportRect(const FloatRect& viewportRect) const
{
FloatSize offset = computeStickyOffset(viewportRect);
return m_layerPositionAtLastLayout + offset - m_stickyOffsetAtLastLayout;
}
} // namespace WebCore
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