1/*
2 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB.  If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 *
19 */
20
21#ifndef RenderOverflow_h
22#define RenderOverflow_h
23
24#include "LayoutRect.h"
25#include <wtf/RefCounted.h>
26
27namespace WebCore
28{
29// RenderOverflow is a class for tracking content that spills out of a box.  This class is used by RenderBox and
30// InlineFlowBox.
31//
32// There are two types of overflow: layout overflow (which is expected to be reachable via scrolling mechanisms) and
33// visual overflow (which is not expected to be reachable via scrolling mechanisms).
34//
35// Layout overflow examples include other boxes that spill out of our box,  For example, in the inline case a tall image
36// could spill out of a line box.
37
38// Examples of visual overflow are shadows, text stroke (and eventually outline and border-image).
39
40// This object is allocated only when some of these fields have non-default values in the owning box.
41class RenderOverflow : public WTF::RefCounted<RenderOverflow> {
42    WTF_MAKE_NONCOPYABLE(RenderOverflow); WTF_MAKE_FAST_ALLOCATED;
43public:
44    RenderOverflow(const LayoutRect& layoutRect, const LayoutRect& visualRect)
45        : m_layoutOverflow(layoutRect)
46        , m_visualOverflow(visualRect)
47    {
48    }
49
50    const LayoutRect layoutOverflowRect() const { return m_layoutOverflow; }
51    const LayoutRect visualOverflowRect() const { return m_visualOverflow; }
52
53    void move(LayoutUnit dx, LayoutUnit dy);
54
55    void addLayoutOverflow(const LayoutRect&);
56    void addVisualOverflow(const LayoutRect&);
57
58    void setLayoutOverflow(const LayoutRect&);
59    void setVisualOverflow(const LayoutRect&);
60
61    LayoutUnit layoutClientAfterEdge() const { return m_layoutClientAfterEdge; }
62    void setLayoutClientAfterEdge(LayoutUnit clientAfterEdge) { m_layoutClientAfterEdge = clientAfterEdge; }
63
64private:
65    LayoutRect m_layoutOverflow;
66    LayoutRect m_visualOverflow;
67
68    LayoutUnit m_layoutClientAfterEdge;
69};
70
71inline void RenderOverflow::move(LayoutUnit dx, LayoutUnit dy)
72{
73    m_layoutOverflow.move(dx, dy);
74    m_visualOverflow.move(dx, dy);
75}
76
77inline void RenderOverflow::addLayoutOverflow(const LayoutRect& rect)
78{
79    LayoutUnit maxX = std::max(rect.maxX(), m_layoutOverflow.maxX());
80    LayoutUnit maxY = std::max(rect.maxY(), m_layoutOverflow.maxY());
81    m_layoutOverflow.setX(std::min(rect.x(), m_layoutOverflow.x()));
82    m_layoutOverflow.setY(std::min(rect.y(), m_layoutOverflow.y()));
83    m_layoutOverflow.setWidth(maxX - m_layoutOverflow.x());
84    m_layoutOverflow.setHeight(maxY - m_layoutOverflow.y());
85}
86
87inline void RenderOverflow::addVisualOverflow(const LayoutRect& rect)
88{
89    LayoutUnit maxX = std::max(rect.maxX(), m_visualOverflow.maxX());
90    LayoutUnit maxY = std::max(rect.maxY(), m_visualOverflow.maxY());
91    m_visualOverflow.setX(std::min(rect.x(), m_visualOverflow.x()));
92    m_visualOverflow.setY(std::min(rect.y(), m_visualOverflow.y()));
93    m_visualOverflow.setWidth(maxX - m_visualOverflow.x());
94    m_visualOverflow.setHeight(maxY - m_visualOverflow.y());
95}
96
97inline void RenderOverflow::setLayoutOverflow(const LayoutRect& rect)
98{
99    m_layoutOverflow = rect;
100}
101
102inline void RenderOverflow::setVisualOverflow(const LayoutRect& rect)
103{
104    m_visualOverflow = rect;
105}
106
107} // namespace WebCore
108
109#endif // RenderOverflow_h
110