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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef MultiColumnFragmentainerGroup_h | |
6 #define MultiColumnFragmentainerGroup_h | |
7 | |
8 #include "core/rendering/RenderMultiColumnFlowThread.h" | |
9 | |
10 namespace blink { | |
11 | |
12 // A group of columns, that are laid out in the inline progression direction, al l with the same | |
13 // column height. | |
14 // | |
15 // When a multicol container is inside another fragmentation context, and said m ulticol container | |
16 // lives in multiple outer fragmentainers (pages / columns), we need to put thes e inner columns into | |
17 // separate groups, with one group per outer fragmentainer. Such a group of colu mns is what | |
18 // comprises a "row of column boxes" in spec lingo. | |
19 // | |
20 // Column balancing, when enabled, takes place within a column fragmentainer gro up. | |
21 // | |
22 // Each fragmentainer group may have its own actual column count (if there are u nused columns | |
23 // because of forced breaks, for example). If there are multiple fragmentainer g roups, the actual | |
24 // column count must not exceed the used column count (the one calculated based on column-count and | |
25 // column-width from CSS), or they'd overflow the outer fragmentainer in the inl ine direction. If we | |
26 // need more columns than what a group has room for, we'll create another group and put them there | |
27 // (and make them appear in the next outer fragmentainer). | |
28 class MultiColumnFragmentainerGroup { | |
29 public: | |
30 MultiColumnFragmentainerGroup(RenderMultiColumnSet&); | |
31 | |
32 bool isLastGroup() const; | |
33 | |
34 // Position within the RenderMultiColumnSet. | |
35 LayoutUnit logicalTop() const { return m_logicalTop; } | |
36 | |
37 LayoutUnit logicalHeight() const { return m_columnHeight; } | |
38 | |
39 LayoutSize offsetFromColumnSet() const; | |
40 | |
41 // The top of our flow thread portion | |
42 LayoutUnit logicalTopInFlowThread() const { return m_logicalTopInFlowThread; } | |
43 void setLogicalTopInFlowThread(LayoutUnit logicalTopInFlowThread) { m_logica lTopInFlowThread = logicalTopInFlowThread; } | |
44 | |
45 // The bottom of our flow thread portion | |
46 LayoutUnit logicalBottomInFlowThread() const { return m_logicalBottomInFlowT hread; } | |
47 void setLogicalBottomInFlowThread(LayoutUnit logicalBottomInFlowThread) { m_ logicalBottomInFlowThread = logicalBottomInFlowThread; } | |
48 | |
49 // The height of our flow thread portion | |
50 LayoutUnit logicalHeightInFlowThread() const { return m_logicalBottomInFlowT hread - m_logicalTopInFlowThread; } | |
51 | |
52 bool heightIsAuto() const; | |
53 void resetColumnHeight(); | |
54 void addContentRun(LayoutUnit endOffsetInFlowThread); | |
55 void updateMinimumColumnHeight(LayoutUnit height) { m_minimumColumnHeight = std::max(height, m_minimumColumnHeight); } | |
56 void recordSpaceShortage(LayoutUnit); | |
57 bool recalculateColumnHeight(BalancedColumnHeightCalculation calculationMode ); | |
58 | |
59 void expandToEncompassFlowThreadOverflow(); | |
60 | |
61 LayoutSize flowThreadTranslationAtOffset(LayoutUnit offsetInFlowThread) cons t; | |
62 LayoutUnit columnLogicalTopForOffset(LayoutUnit offsetInFlowThread) const; | |
63 void collectLayerFragments(LayerFragments&, const LayoutRect& layerBoundingB ox, const LayoutRect& dirtyRect) const; | |
64 LayoutRect calculateOverflow() const; | |
65 | |
66 // The "CSS actual" value of column-count. This includes overflowing columns , if any. | |
67 unsigned actualColumnCount() const; | |
68 | |
69 private: | |
70 LayoutUnit heightAdjustedForRowOffset(LayoutUnit height) const; | |
71 LayoutUnit calculateMaxColumnHeight() const; | |
72 void setAndConstrainColumnHeight(LayoutUnit); | |
73 | |
74 // Return the index of the content run with the currently tallest columns, t aking all implicit | |
75 // breaks assumed so far into account. | |
76 unsigned findRunWithTallestColumns() const; | |
Julien - ping for review
2015/02/11 07:25:29
I think we should use size_t for indexes (we are i
mstensho (USE GERRIT)
2015/02/11 09:49:55
This is just code that got moved. Let's fix this i
| |
77 | |
78 // Given the current list of content runs, make assumptions about where we n eed to insert | |
79 // implicit breaks (if there's room for any at all; depending on the number of explicit breaks), | |
80 // and store the results. This is needed in order to balance the columns. | |
81 void distributeImplicitBreaks(); | |
82 | |
83 LayoutUnit calculateColumnHeight(BalancedColumnHeightCalculation) const; | |
84 | |
85 LayoutRect columnRectAt(unsigned columnIndex) const; | |
86 LayoutRect flowThreadPortionRectAt(unsigned columnIndex) const; | |
87 LayoutRect flowThreadPortionOverflowRect(const LayoutRect& flowThreadPortion , unsigned columnIndex, unsigned columnCount, LayoutUnit columnGap) const; | |
88 | |
89 enum ColumnIndexCalculationMode { | |
90 ClampToExistingColumns, // Stay within the range of already existing col umns. | |
91 AssumeNewColumns // Allow column indices outside the range of already ex isting columns. | |
92 }; | |
93 unsigned columnIndexAtOffset(LayoutUnit offsetInFlowThread, ColumnIndexCalcu lationMode = ClampToExistingColumns) const; | |
94 | |
95 RenderMultiColumnSet& m_columnSet; | |
96 | |
97 LayoutUnit m_logicalTop; | |
98 LayoutUnit m_logicalTopInFlowThread; | |
99 LayoutUnit m_logicalBottomInFlowThread; | |
100 | |
101 LayoutUnit m_columnHeight; | |
102 | |
103 // The following variables are used when balancing the column set. | |
104 LayoutUnit m_maxColumnHeight; // Maximum column height allowed. | |
105 LayoutUnit m_minSpaceShortage; // The smallest amout of space shortage that caused a column break. | |
106 LayoutUnit m_minimumColumnHeight; | |
107 | |
108 // A run of content without explicit (forced) breaks; i.e. a flow thread por tion between two | |
109 // explicit breaks, between flow thread start and an explicit break, between an explicit break | |
110 // and flow thread end, or, in cases when there are no explicit breaks at al l: between flow | |
111 // thread portion start and flow thread portion end. We need to know where t he explicit breaks | |
112 // are, in order to figure out where the implicit breaks will end up, so tha t we get the columns | |
113 // properly balanced. A content run starts out as representing one single co lumn, and will | |
114 // represent one additional column for each implicit break "inserted" there. | |
115 class ContentRun { | |
116 public: | |
117 ContentRun(LayoutUnit breakOffset) | |
118 : m_breakOffset(breakOffset) | |
119 , m_assumedImplicitBreaks(0) { } | |
120 | |
121 unsigned assumedImplicitBreaks() const { return m_assumedImplicitBreaks; } | |
122 void assumeAnotherImplicitBreak() { m_assumedImplicitBreaks++; } | |
123 LayoutUnit breakOffset() const { return m_breakOffset; } | |
124 | |
125 // Return the column height that this content run would require, conside ring the implicit | |
126 // breaks assumed so far. | |
127 LayoutUnit columnLogicalHeight(LayoutUnit startOffset) const { return ce ilf((m_breakOffset - startOffset).toFloat() / float(m_assumedImplicitBreaks + 1) ); } | |
128 | |
129 private: | |
130 LayoutUnit m_breakOffset; // Flow thread offset where this run ends. | |
131 unsigned m_assumedImplicitBreaks; // Number of implicit breaks in this r un assumed so far. | |
132 }; | |
133 Vector<ContentRun, 1> m_contentRuns; | |
134 }; | |
135 | |
136 // List of all fragmentainer groups within a column set. There will always be at least one | |
137 // group. Deleting the one group is not allowed (or possible). There will be mor e than one group if | |
138 // the owning column set lives in multiple outer fragmentainers (e.g. multicol i nside paged media). | |
139 class MultiColumnFragmentainerGroupList : public Vector<MultiColumnFragmentainer Group, 1> { | |
Nico
2015/04/09 04:39:34
Let's not derive from container types. If your cla
| |
140 public: | |
141 MultiColumnFragmentainerGroupList(RenderMultiColumnSet&); | |
142 | |
143 // Add an additional fragmentainer group to the end of the list, and return it. | |
144 MultiColumnFragmentainerGroup& addExtraGroup(); | |
145 | |
146 // Remove all fragmentainer groups but the first one. | |
147 void deleteExtraGroups(); | |
148 | |
149 private: | |
150 RenderMultiColumnSet& m_columnSet; | |
151 }; | |
152 | |
153 } // namespace blink | |
154 | |
155 #endif // MultiColumnFragmentainerGroup_h | |
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