root/Source/core/rendering/RenderOverflow.h

INCLUDED FROM

/*
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef RenderOverflow_h
#define RenderOverflow_h

#include "platform/geometry/LayoutRect.h"

namespace WebCore
{
// RenderOverflow is a class for tracking content that spills out of a box.  This class is used by RenderBox and
// InlineFlowBox.
//
// There are two types of overflow: layout overflow (which is expected to be reachable via scrolling mechanisms) and
// visual overflow (which is not expected to be reachable via scrolling mechanisms).
//
// Layout overflow examples include other boxes that spill out of our box,  For example, in the inline case a tall image
// could spill out of a line box.

// Examples of visual overflow are shadows, text stroke (and eventually outline and border-image).

// This object is allocated only when some of these fields have non-default values in the owning box.
class RenderOverflow {
    WTF_MAKE_NONCOPYABLE(RenderOverflow); WTF_MAKE_FAST_ALLOCATED;
public:
    RenderOverflow(const LayoutRect& layoutRect, const LayoutRect& visualRect)
        : m_layoutOverflow(layoutRect)
        , m_visualOverflow(visualRect)
    {
    }

    const LayoutRect layoutOverflowRect() const { return m_layoutOverflow; }
    const LayoutRect visualOverflowRect() const { return m_visualOverflow; }
    LayoutRect contentsVisualOverflowRect() const { return m_contentsVisualOverflow; }

    void move(LayoutUnit dx, LayoutUnit dy);

    void addLayoutOverflow(const LayoutRect&);
    void addVisualOverflow(const LayoutRect&);
    void addContentsVisualOverflow(const LayoutRect& rect) { m_contentsVisualOverflow.unite(rect); }

    void setLayoutOverflow(const LayoutRect&);
    void setVisualOverflow(const LayoutRect&);

    LayoutUnit layoutClientAfterEdge() const { return m_layoutClientAfterEdge; }
    void setLayoutClientAfterEdge(LayoutUnit clientAfterEdge) { m_layoutClientAfterEdge = clientAfterEdge; }

private:
    LayoutRect m_layoutOverflow;
    LayoutRect m_visualOverflow;
    LayoutRect m_contentsVisualOverflow;

    LayoutUnit m_layoutClientAfterEdge;
};

inline void RenderOverflow::move(LayoutUnit dx, LayoutUnit dy)
{
    m_layoutOverflow.move(dx, dy);
    m_visualOverflow.move(dx, dy);
    m_contentsVisualOverflow.move(dx, dy);
}

inline void RenderOverflow::addLayoutOverflow(const LayoutRect& rect)
{
    LayoutUnit maxX = std::max(rect.maxX(), m_layoutOverflow.maxX());
    LayoutUnit maxY = std::max(rect.maxY(), m_layoutOverflow.maxY());
    LayoutUnit minX = std::min(rect.x(), m_layoutOverflow.x());
    LayoutUnit minY = std::min(rect.y(), m_layoutOverflow.y());
    // In case the width/height is larger than LayoutUnit can represent, fix the right/bottom edge and shift the top/left ones
    m_layoutOverflow.setWidth(maxX - minX);
    m_layoutOverflow.setHeight(maxY - minY);
    m_layoutOverflow.setX(maxX - m_layoutOverflow.width());
    m_layoutOverflow.setY(maxY - m_layoutOverflow.height());
}

inline void RenderOverflow::addVisualOverflow(const LayoutRect& rect)
{
    LayoutUnit maxX = std::max(rect.maxX(), m_visualOverflow.maxX());
    LayoutUnit maxY = std::max(rect.maxY(), m_visualOverflow.maxY());
    m_visualOverflow.setX(std::min(rect.x(), m_visualOverflow.x()));
    m_visualOverflow.setY(std::min(rect.y(), m_visualOverflow.y()));
    m_visualOverflow.setWidth(maxX - m_visualOverflow.x());
    m_visualOverflow.setHeight(maxY - m_visualOverflow.y());
}

inline void RenderOverflow::setLayoutOverflow(const LayoutRect& rect)
{
    m_layoutOverflow = rect;
}

inline void RenderOverflow::setVisualOverflow(const LayoutRect& rect)
{
    m_visualOverflow = rect;
}

} // namespace WebCore

#endif // RenderOverflow_h