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1 /*
2  * Copyright (C) 2010, 2011 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 ColumnInfo_h
27 #define ColumnInfo_h
28 
29 #include "platform/LayoutUnit.h"
30 #include "wtf/Vector.h"
31 
32 namespace WebCore {
33 
34 class ColumnInfo {
35     WTF_MAKE_NONCOPYABLE(ColumnInfo); WTF_MAKE_FAST_ALLOCATED;
36 public:
ColumnInfo()37     ColumnInfo()
38         : m_desiredColumnWidth(0)
39         , m_desiredColumnCount(1)
40         , m_progressionAxis(InlineAxis)
41         , m_columnCount(1)
42         , m_columnHeight(0)
43         , m_minimumColumnHeight(0)
44         , m_forcedBreaks(0)
45         , m_maximumDistanceBetweenForcedBreaks(0)
46         , m_forcedBreakOffset(0)
47     {
48     }
49 
desiredColumnWidth()50     LayoutUnit desiredColumnWidth() const { return m_desiredColumnWidth; }
setDesiredColumnWidth(LayoutUnit width)51     void setDesiredColumnWidth(LayoutUnit width) { m_desiredColumnWidth = width; }
52 
desiredColumnCount()53     unsigned desiredColumnCount() const { return m_desiredColumnCount; }
setDesiredColumnCount(unsigned count)54     void setDesiredColumnCount(unsigned count) { m_desiredColumnCount = count; }
55 
56     enum Axis { InlineAxis, BlockAxis };
57 
progressionAxis()58     Axis progressionAxis() const { return m_progressionAxis; }
setProgressionAxis(Axis progressionAxis)59     void setProgressionAxis(Axis progressionAxis) { m_progressionAxis = progressionAxis; }
60 
columnCount()61     unsigned columnCount() const { return m_columnCount; }
columnHeight()62     LayoutUnit columnHeight() const { return m_columnHeight; }
63 
64     // Set our count and height.  This is enough info for a RenderBlock to compute page rects
65     // dynamically.
setColumnCountAndHeight(int count,LayoutUnit height)66     void setColumnCountAndHeight(int count, LayoutUnit height)
67     {
68         m_columnCount = count;
69         m_columnHeight = height;
70     }
setColumnHeight(LayoutUnit height)71     void setColumnHeight(LayoutUnit height) { m_columnHeight = height; }
72 
updateMinimumColumnHeight(LayoutUnit height)73     void updateMinimumColumnHeight(LayoutUnit height) { m_minimumColumnHeight = std::max(height, m_minimumColumnHeight); }
minimumColumnHeight()74     LayoutUnit minimumColumnHeight() const { return m_minimumColumnHeight; }
75 
forcedBreaks()76     int forcedBreaks() const { return m_forcedBreaks; }
forcedBreakOffset()77     LayoutUnit forcedBreakOffset() const { return m_forcedBreakOffset; }
maximumDistanceBetweenForcedBreaks()78     LayoutUnit maximumDistanceBetweenForcedBreaks() const { return m_maximumDistanceBetweenForcedBreaks; }
clearForcedBreaks()79     void clearForcedBreaks()
80     {
81         m_forcedBreaks = 0;
82         m_maximumDistanceBetweenForcedBreaks = 0;
83         m_forcedBreakOffset = 0;
84     }
addForcedBreak(LayoutUnit offsetFromFirstPage)85     void addForcedBreak(LayoutUnit offsetFromFirstPage)
86     {
87         ASSERT(!m_columnHeight);
88         LayoutUnit distanceFromLastBreak = offsetFromFirstPage - m_forcedBreakOffset;
89         if (!distanceFromLastBreak)
90             return;
91         m_forcedBreaks++;
92         m_maximumDistanceBetweenForcedBreaks = std::max(m_maximumDistanceBetweenForcedBreaks, distanceFromLastBreak);
93         m_forcedBreakOffset = offsetFromFirstPage;
94     }
95 
96 private:
97     LayoutUnit m_desiredColumnWidth;
98     unsigned m_desiredColumnCount;
99     Axis m_progressionAxis;
100 
101     unsigned m_columnCount;
102     LayoutUnit m_columnHeight;
103     LayoutUnit m_minimumColumnHeight;
104     int m_forcedBreaks; // FIXME: We will ultimately need to cache more information to balance around forced breaks properly.
105     LayoutUnit m_maximumDistanceBetweenForcedBreaks;
106     LayoutUnit m_forcedBreakOffset;
107 };
108 
109 }
110 
111 #endif
112