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* Copyright (C) 2012 Apple Inc. All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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#include "ScrollingConstraints.h"
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FloatPoint FixedPositionViewportConstraints::layerPositionForViewportRect(const FloatRect& viewportRect) const
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if (hasAnchorEdge(AnchorEdgeLeft))
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offset.setWidth(viewportRect.x() - m_viewportRectAtLastLayout.x());
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else if (hasAnchorEdge(AnchorEdgeRight))
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offset.setWidth(viewportRect.maxX() - m_viewportRectAtLastLayout.maxX());
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if (hasAnchorEdge(AnchorEdgeTop))
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offset.setHeight(viewportRect.y() - m_viewportRectAtLastLayout.y());
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else if (hasAnchorEdge(AnchorEdgeBottom))
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offset.setHeight(viewportRect.maxY() - m_viewportRectAtLastLayout.maxY());
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return m_layerPositionAtLastLayout + offset;
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FloatSize StickyPositionViewportConstraints::computeStickyOffset(const FloatRect& viewportRect) const
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FloatRect boxRect = m_absoluteStickyBoxRect;
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if (hasAnchorEdge(AnchorEdgeRight)) {
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float rightLimit = viewportRect.maxX() - m_rightOffset;
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float rightDelta = std::min<float>(0, rightLimit - m_absoluteStickyBoxRect.maxX());
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float availableSpace = std::min<float>(0, m_absoluteContainingBlockRect.x() - m_absoluteStickyBoxRect.x());
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if (rightDelta < availableSpace)
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rightDelta = availableSpace;
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boxRect.move(rightDelta, 0);
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if (hasAnchorEdge(AnchorEdgeLeft)) {
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float leftLimit = viewportRect.x() + m_leftOffset;
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float leftDelta = std::max<float>(0, leftLimit - m_absoluteStickyBoxRect.x());
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float availableSpace = std::max<float>(0, m_absoluteContainingBlockRect.maxX() - m_absoluteStickyBoxRect.maxX());
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if (leftDelta > availableSpace)
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leftDelta = availableSpace;
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boxRect.move(leftDelta, 0);
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if (hasAnchorEdge(AnchorEdgeBottom)) {
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float bottomLimit = viewportRect.maxY() - m_bottomOffset;
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float bottomDelta = std::min<float>(0, bottomLimit - m_absoluteStickyBoxRect.maxY());
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float availableSpace = std::min<float>(0, m_absoluteContainingBlockRect.y() - m_absoluteStickyBoxRect.y());
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if (bottomDelta < availableSpace)
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bottomDelta = availableSpace;
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boxRect.move(0, bottomDelta);
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if (hasAnchorEdge(AnchorEdgeTop)) {
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float topLimit = viewportRect.y() + m_topOffset;
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float topDelta = std::max<float>(0, topLimit - m_absoluteStickyBoxRect.y());
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float availableSpace = std::max<float>(0, m_absoluteContainingBlockRect.maxY() - m_absoluteStickyBoxRect.maxY());
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if (topDelta > availableSpace)
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topDelta = availableSpace;
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boxRect.move(0, topDelta);
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return boxRect.location() - m_absoluteStickyBoxRect.location();
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FloatPoint StickyPositionViewportConstraints::layerPositionForViewportRect(const FloatRect& viewportRect) const
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FloatSize offset = computeStickyOffset(viewportRect);
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return m_layerPositionAtLastLayout + offset - m_stickyOffsetAtLastLayout;
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} // namespace WebCore