--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/rendering/RenderOverflow.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,153 @@
+/*
+ * 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 "IntRect.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 : public Noncopyable {
+public:
+    RenderOverflow(const IntRect& defaultRect = IntRect()) 
+        : m_topLayoutOverflow(defaultRect.y())
+        , m_bottomLayoutOverflow(defaultRect.bottom())
+        , m_leftLayoutOverflow(defaultRect.x())
+        , m_rightLayoutOverflow(defaultRect.right())
+        , m_topVisualOverflow(defaultRect.y())
+        , m_bottomVisualOverflow(defaultRect.bottom())
+        , m_leftVisualOverflow(defaultRect.x())
+        , m_rightVisualOverflow(defaultRect.right())
+    {
+    }
+   
+    int topLayoutOverflow() const { return m_topLayoutOverflow; }
+    int bottomLayoutOverflow() const { return m_bottomLayoutOverflow; }
+    int leftLayoutOverflow() const { return m_leftLayoutOverflow; }
+    int rightLayoutOverflow() const { return m_rightLayoutOverflow; }
+    IntRect layoutOverflowRect() const;
+
+    int topVisualOverflow() const { return m_topVisualOverflow; }
+    int bottomVisualOverflow() const { return m_bottomVisualOverflow; }
+    int leftVisualOverflow() const { return m_leftVisualOverflow; }
+    int rightVisualOverflow() const { return m_rightVisualOverflow; }
+    IntRect visualOverflowRect() const;
+
+    IntRect visibleOverflowRect() const;
+
+    void setTopLayoutOverflow(int overflow) { m_topLayoutOverflow = overflow; }
+    void setBottomLayoutOverflow(int overflow) { m_bottomLayoutOverflow = overflow; }
+    void setLeftLayoutOverflow(int overflow) { m_leftLayoutOverflow = overflow; }
+    void setRightLayoutOverflow(int overflow) { m_rightLayoutOverflow = overflow; }
+    
+    void setTopVisualOverflow(int overflow) { m_topVisualOverflow = overflow; }
+    void setBottomVisualOverflow(int overflow) { m_bottomVisualOverflow = overflow; }
+    void setLeftVisualOverflow(int overflow) { m_leftVisualOverflow = overflow; }
+    void setRightVisualOverflow(int overflow) { m_rightVisualOverflow = overflow; }
+    
+    void move(int dx, int dy);
+    
+    void addLayoutOverflow(const IntRect&);
+    void addVisualOverflow(const IntRect&);
+
+    void resetLayoutOverflow(const IntRect& defaultRect);
+
+private:
+    int m_topLayoutOverflow;
+    int m_bottomLayoutOverflow;
+    int m_leftLayoutOverflow;
+    int m_rightLayoutOverflow;
+
+    int m_topVisualOverflow;
+    int m_bottomVisualOverflow;
+    int m_leftVisualOverflow;
+    int m_rightVisualOverflow;
+};
+
+inline IntRect RenderOverflow::layoutOverflowRect() const
+{
+    return IntRect(m_leftLayoutOverflow, m_topLayoutOverflow, m_rightLayoutOverflow - m_leftLayoutOverflow, m_bottomLayoutOverflow - m_topLayoutOverflow);
+}
+
+inline IntRect RenderOverflow::visualOverflowRect() const
+{
+    return IntRect(m_leftVisualOverflow, m_topVisualOverflow, m_rightVisualOverflow - m_leftVisualOverflow, m_bottomVisualOverflow - m_topVisualOverflow);
+}
+
+inline IntRect RenderOverflow::visibleOverflowRect() const
+{
+    IntRect combinedRect(layoutOverflowRect());
+    combinedRect.unite(visualOverflowRect());
+    return combinedRect;
+}
+
+inline void RenderOverflow::move(int dx, int dy)
+{
+    m_topLayoutOverflow += dy;
+    m_bottomLayoutOverflow += dy;
+    m_leftLayoutOverflow += dx;
+    m_rightLayoutOverflow += dx;
+    
+    m_topVisualOverflow += dy;
+    m_bottomVisualOverflow += dy;
+    m_leftVisualOverflow += dx;
+    m_rightVisualOverflow += dx;
+}
+
+inline void RenderOverflow::addLayoutOverflow(const IntRect& rect)
+{
+    m_topLayoutOverflow = std::min(rect.y(), m_topLayoutOverflow);
+    m_bottomLayoutOverflow = std::max(rect.bottom(), m_bottomLayoutOverflow);
+    m_leftLayoutOverflow = std::min(rect.x(), m_leftLayoutOverflow);
+    m_rightLayoutOverflow = std::max(rect.right(), m_rightLayoutOverflow);
+}
+
+inline void RenderOverflow::addVisualOverflow(const IntRect& rect)
+{
+    m_topVisualOverflow = std::min(rect.y(), m_topVisualOverflow);
+    m_bottomVisualOverflow = std::max(rect.bottom(), m_bottomVisualOverflow);
+    m_leftVisualOverflow = std::min(rect.x(), m_leftVisualOverflow);
+    m_rightVisualOverflow = std::max(rect.right(), m_rightVisualOverflow);
+}
+
+inline void RenderOverflow::resetLayoutOverflow(const IntRect& rect)
+{
+    m_topLayoutOverflow = rect.y();
+    m_bottomLayoutOverflow = rect.bottom();
+    m_leftLayoutOverflow = rect.x();
+    m_rightLayoutOverflow = rect.right();
+}
+
+} // namespace WebCore
+
+#endif // RenderOverflow_h