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1 /*
2  * Copyright (C) 2007 Apple Inc.  All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #ifndef LayoutState_h
27 #define LayoutState_h
28 
29 #include "IntRect.h"
30 #include "IntSize.h"
31 #include <wtf/Noncopyable.h>
32 
33 namespace WebCore {
34 
35 class ColumnInfo;
36 class RenderArena;
37 class RenderBox;
38 class RenderObject;
39 
40 class LayoutState {
41     WTF_MAKE_NONCOPYABLE(LayoutState);
42 public:
LayoutState()43     LayoutState()
44         : m_clipped(false)
45         , m_pageLogicalHeight(0)
46         , m_pageLogicalHeightChanged(false)
47         , m_columnInfo(0)
48         , m_next(0)
49 #ifndef NDEBUG
50         , m_renderer(0)
51 #endif
52     {
53     }
54 
55     LayoutState(LayoutState*, RenderBox*, const IntSize& offset, int pageHeight, bool pageHeightChanged, ColumnInfo*);
56     LayoutState(RenderObject*);
57 
58     void destroy(RenderArena*);
59 
60     // Overloaded new operator.
61     void* operator new(size_t, RenderArena*) throw();
62 
63     // Overridden to prevent the normal delete from being called.
64     void operator delete(void*, size_t);
65 
66     void clearPaginationInformation();
isPaginatingColumns()67     bool isPaginatingColumns() const { return m_columnInfo; }
isPaginated()68     bool isPaginated() const { return m_pageLogicalHeight || m_columnInfo; }
69 
70     // The page logical offset is the object's offset from the top of the page in the page progression
71     // direction (so an x-offset in vertical text and a y-offset for horizontal text).
72     int pageLogicalOffset(int childLogicalOffset) const;
73 
74     void addForcedColumnBreak(int childLogicalOffset);
75 
pageLogicalHeight()76     bool pageLogicalHeight() const { return m_pageLogicalHeight; }
pageLogicalHeightChanged()77     bool pageLogicalHeightChanged() const { return m_pageLogicalHeightChanged; }
78 
79 private:
80     // The normal operator new is disallowed.
81     void* operator new(size_t) throw();
82 
83 public:
84     bool m_clipped;
85     IntRect m_clipRect;
86     IntSize m_paintOffset; // x/y offset from container.  Includes relative positioning and scroll offsets.
87     IntSize m_layoutOffset; // x/y offset from container.  Does not include relative positioning or scroll offsets.
88     IntSize m_layoutDelta; // Transient offset from the final position of the object
89                            // used to ensure that repaints happen in the correct place.
90                            // This is a total delta accumulated from the root.
91 
92     int m_pageLogicalHeight; // The current page height for the pagination model that encloses us.
93     bool m_pageLogicalHeightChanged; // If our page height has changed, this will force all blocks to relayout.
94     IntSize m_pageOffset; // The offset of the start of the first page in the nearest enclosing pagination model.
95     ColumnInfo* m_columnInfo; // If the enclosing pagination model is a column model, then this will store column information for easy retrieval/manipulation.
96 
97     LayoutState* m_next;
98 #ifndef NDEBUG
99     RenderObject* m_renderer;
100 #endif
101 };
102 
103 } // namespace WebCore
104 
105 #endif // LayoutState_h
106