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 "platform/geometry/LayoutRect.h"
25
26namespace blink
27{
28// RenderOverflow is a class for tracking content that spills out of a box.  This class is used by RenderBox and
29// InlineFlowBox.
30//
31// There are two types of overflow: layout overflow (which is expected to be reachable via scrolling mechanisms) and
32// visual overflow (which is not expected to be reachable via scrolling mechanisms).
33//
34// Layout overflow examples include other boxes that spill out of our box,  For example, in the inline case a tall image
35// could spill out of a line box.
36
37// Examples of visual overflow are shadows, text stroke (and eventually outline and border-image).
38
39// This object is allocated only when some of these fields have non-default values in the owning box.
40class RenderOverflow {
41    WTF_MAKE_NONCOPYABLE(RenderOverflow); WTF_MAKE_FAST_ALLOCATED;
42public:
43    RenderOverflow(const LayoutRect& layoutRect, const LayoutRect& visualRect)
44        : m_layoutOverflow(layoutRect)
45        , m_visualOverflow(visualRect)
46    {
47    }
48
49    const LayoutRect layoutOverflowRect() const { return m_layoutOverflow; }
50    const LayoutRect visualOverflowRect() const { return m_visualOverflow; }
51    LayoutRect contentsVisualOverflowRect() const { return m_contentsVisualOverflow; }
52
53    void move(LayoutUnit dx, LayoutUnit dy);
54
55    void addLayoutOverflow(const LayoutRect&);
56    void addVisualOverflow(const LayoutRect&);
57    void addContentsVisualOverflow(const LayoutRect& rect) { m_contentsVisualOverflow.unite(rect); }
58
59    void setLayoutOverflow(const LayoutRect&);
60    void setVisualOverflow(const LayoutRect&);
61
62    LayoutUnit layoutClientAfterEdge() const { return m_layoutClientAfterEdge; }
63    void setLayoutClientAfterEdge(LayoutUnit clientAfterEdge) { m_layoutClientAfterEdge = clientAfterEdge; }
64
65private:
66    LayoutRect m_layoutOverflow;
67    LayoutRect m_visualOverflow;
68    LayoutRect m_contentsVisualOverflow;
69
70    LayoutUnit m_layoutClientAfterEdge;
71};
72
73inline void RenderOverflow::move(LayoutUnit dx, LayoutUnit dy)
74{
75    m_layoutOverflow.move(dx, dy);
76    m_visualOverflow.move(dx, dy);
77    m_contentsVisualOverflow.move(dx, dy);
78}
79
80inline void RenderOverflow::addLayoutOverflow(const LayoutRect& rect)
81{
82    LayoutUnit maxX = std::max(rect.maxX(), m_layoutOverflow.maxX());
83    LayoutUnit maxY = std::max(rect.maxY(), m_layoutOverflow.maxY());
84    LayoutUnit minX = std::min(rect.x(), m_layoutOverflow.x());
85    LayoutUnit minY = std::min(rect.y(), m_layoutOverflow.y());
86    // In case the width/height is larger than LayoutUnit can represent, fix the right/bottom edge and shift the top/left ones
87    m_layoutOverflow.setWidth(maxX - minX);
88    m_layoutOverflow.setHeight(maxY - minY);
89    m_layoutOverflow.setX(maxX - m_layoutOverflow.width());
90    m_layoutOverflow.setY(maxY - m_layoutOverflow.height());
91}
92
93inline void RenderOverflow::addVisualOverflow(const LayoutRect& rect)
94{
95    LayoutUnit maxX = std::max(rect.maxX(), m_visualOverflow.maxX());
96    LayoutUnit maxY = std::max(rect.maxY(), m_visualOverflow.maxY());
97    m_visualOverflow.setX(std::min(rect.x(), m_visualOverflow.x()));
98    m_visualOverflow.setY(std::min(rect.y(), m_visualOverflow.y()));
99    m_visualOverflow.setWidth(maxX - m_visualOverflow.x());
100    m_visualOverflow.setHeight(maxY - m_visualOverflow.y());
101}
102
103inline void RenderOverflow::setLayoutOverflow(const LayoutRect& rect)
104{
105    m_layoutOverflow = rect;
106}
107
108inline void RenderOverflow::setVisualOverflow(const LayoutRect& rect)
109{
110    m_visualOverflow = rect;
111}
112
113} // namespace blink
114
115#endif // RenderOverflow_h
116