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
32namespace blink {
33
34class ColumnInfo {
35    WTF_MAKE_NONCOPYABLE(ColumnInfo); WTF_MAKE_FAST_ALLOCATED;
36public:
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
50    LayoutUnit desiredColumnWidth() const { return m_desiredColumnWidth; }
51    void setDesiredColumnWidth(LayoutUnit width) { m_desiredColumnWidth = width; }
52
53    unsigned desiredColumnCount() const { return m_desiredColumnCount; }
54    void setDesiredColumnCount(unsigned count) { m_desiredColumnCount = count; }
55
56    enum Axis { InlineAxis, BlockAxis };
57
58    Axis progressionAxis() const { return m_progressionAxis; }
59    void setProgressionAxis(Axis progressionAxis) { m_progressionAxis = progressionAxis; }
60
61    unsigned columnCount() const { return m_columnCount; }
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.
66    void setColumnCountAndHeight(int count, LayoutUnit height)
67    {
68        m_columnCount = count;
69        m_columnHeight = height;
70    }
71    void setColumnHeight(LayoutUnit height) { m_columnHeight = height; }
72
73    void updateMinimumColumnHeight(LayoutUnit height) { m_minimumColumnHeight = std::max(height, m_minimumColumnHeight); }
74    LayoutUnit minimumColumnHeight() const { return m_minimumColumnHeight; }
75
76    int forcedBreaks() const { return m_forcedBreaks; }
77    LayoutUnit forcedBreakOffset() const { return m_forcedBreakOffset; }
78    LayoutUnit maximumDistanceBetweenForcedBreaks() const { return m_maximumDistanceBetweenForcedBreaks; }
79    void clearForcedBreaks()
80    {
81        m_forcedBreaks = 0;
82        m_maximumDistanceBetweenForcedBreaks = 0;
83        m_forcedBreakOffset = 0;
84    }
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
96private:
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