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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 MultiColumnRow_h | |
6 #define MultiColumnRow_h | |
7 | |
8 #include "core/rendering/RenderMultiColumnFlowThread.h" | |
9 | |
10 namespace blink { | |
11 | |
12 class MultiColumnRow { | |
Julien - ping for review
2015/01/29 17:37:47
We would need a class comment about this. I still
mstensho (USE GERRIT)
2015/02/02 17:57:23
Done.
| |
13 public: | |
14 MultiColumnRow(RenderMultiColumnSet&); | |
15 | |
16 // FIXME: implement these. For now we only support one row. | |
17 MultiColumnRow* previousRow() { return 0; } | |
18 MultiColumnRow* nextRow() { return 0; } | |
19 const MultiColumnRow* previousRow() const { return 0; } | |
20 const MultiColumnRow* nextRow() const { return 0; } | |
21 | |
22 // Position within the RenderMultiColumnSet. | |
23 LayoutUnit logicalTop() const { return m_logicalTop; } | |
24 | |
25 LayoutUnit logicalHeight() const { return m_columnHeight; } | |
26 | |
27 LayoutSize offsetFromColumnSet() const; | |
28 | |
29 // The top of our flow thread portion | |
30 LayoutUnit logicalTopInFlowThread() const { return m_logicalTopInFlowThread; } | |
31 void setLogicalTopInFlowThread(LayoutUnit logicalTopInFlowThread) { m_logica lTopInFlowThread = logicalTopInFlowThread; } | |
32 | |
33 // The bottom of our flow thread portion | |
34 LayoutUnit logicalBottomInFlowThread() const { return m_logicalBottomInFlowT hread; } | |
35 void setLogicalBottomInFlowThread(LayoutUnit logicalBottomInFlowThread) { m_ logicalBottomInFlowThread = logicalBottomInFlowThread; } | |
36 | |
37 // The height of our flow thread portion | |
38 LayoutUnit logicalHeightInFlowThread() const { return m_logicalBottomInFlowT hread - m_logicalTopInFlowThread; } | |
39 | |
40 bool heightIsAuto() const; | |
41 void resetColumnHeight(); | |
42 void addContentRun(LayoutUnit endOffsetInFlowThread); | |
43 void updateMinimumColumnHeight(LayoutUnit height) { m_minimumColumnHeight = std::max(height, m_minimumColumnHeight); } | |
44 void recordSpaceShortage(LayoutUnit); | |
45 bool recalculateColumnHeight(BalancedColumnHeightCalculation calculationMode ); | |
46 | |
47 void expandToEncompassFlowThreadOverflow(); | |
48 | |
49 LayoutSize flowThreadTranslationAtOffset(LayoutUnit offsetInFlowThread) cons t; | |
50 LayoutUnit columnLogicalTopForOffset(LayoutUnit offsetInFlowThread) const; | |
51 void collectLayerFragments(LayerFragments&, const LayoutRect& layerBoundingB ox, const LayoutRect& dirtyRect); | |
52 LayoutRect calculateOverflow() const; | |
53 | |
54 // The "CSS actual" value of column-count. This includes overflowing columns , if any. | |
55 unsigned actualColumnCount() const; | |
56 | |
57 private: | |
58 LayoutUnit heightAdjustedForRowOffset(LayoutUnit height) const; | |
59 LayoutUnit calculateMaxColumnHeight() const; | |
60 void setAndConstrainColumnHeight(LayoutUnit); | |
61 | |
62 // Return the index of the content run with the currently tallest columns, t aking all implicit | |
63 // breaks assumed so far into account. | |
64 unsigned findRunWithTallestColumns() const; | |
65 | |
66 // Given the current list of content runs, make assumptions about where we n eed to insert | |
67 // implicit breaks (if there's room for any at all; depending on the number of explicit breaks), | |
68 // and store the results. This is needed in order to balance the columns. | |
69 void distributeImplicitBreaks(); | |
70 | |
71 LayoutUnit calculateColumnHeight(BalancedColumnHeightCalculation) const; | |
72 | |
73 LayoutRect columnRectAt(unsigned columnIndex) const; | |
74 LayoutRect flowThreadPortionRectAt(unsigned columnIndex) const; | |
75 LayoutRect flowThreadPortionOverflowRect(const LayoutRect& flowThreadPortion , unsigned columnIndex, unsigned columnCount, LayoutUnit columnGap) const; | |
76 | |
77 enum ColumnIndexCalculationMode { | |
78 ClampToExistingColumns, // Stay within the range of already existing col umns. | |
79 AssumeNewColumns // Allow column indices outside the range of already ex isting columns. | |
80 }; | |
81 unsigned columnIndexAtOffset(LayoutUnit offsetInFlowThread, ColumnIndexCalcu lationMode = ClampToExistingColumns) const; | |
82 | |
83 RenderMultiColumnSet& m_columnSet; | |
84 | |
85 LayoutUnit m_logicalTop; | |
86 LayoutUnit m_logicalTopInFlowThread; | |
87 LayoutUnit m_logicalBottomInFlowThread; | |
88 | |
89 LayoutUnit m_columnHeight; | |
90 | |
91 // The following variables are used when balancing the column set. | |
92 LayoutUnit m_maxColumnHeight; // Maximum column height allowed. | |
93 LayoutUnit m_minSpaceShortage; // The smallest amout of space shortage that caused a column break. | |
94 LayoutUnit m_minimumColumnHeight; | |
95 | |
96 // A run of content without explicit (forced) breaks; i.e. a flow thread por tion between two | |
97 // explicit breaks, between flow thread start and an explicit break, between an explicit break | |
98 // and flow thread end, or, in cases when there are no explicit breaks at al l: between flow | |
99 // thread portion start and flow thread portion end. We need to know where t he explicit breaks | |
100 // are, in order to figure out where the implicit breaks will end up, so tha t we get the columns | |
101 // properly balanced. A content run starts out as representing one single co lumn, and will | |
102 // represent one additional column for each implicit break "inserted" there. | |
103 class ContentRun { | |
104 public: | |
105 ContentRun(LayoutUnit breakOffset) | |
106 : m_breakOffset(breakOffset) | |
107 , m_assumedImplicitBreaks(0) { } | |
108 | |
109 unsigned assumedImplicitBreaks() const { return m_assumedImplicitBreaks; } | |
110 void assumeAnotherImplicitBreak() { m_assumedImplicitBreaks++; } | |
111 LayoutUnit breakOffset() const { return m_breakOffset; } | |
112 | |
113 // Return the column height that this content run would require, conside ring the implicit | |
114 // breaks assumed so far. | |
115 LayoutUnit columnLogicalHeight(LayoutUnit startOffset) const { return ce ilf((m_breakOffset - startOffset).toFloat() / float(m_assumedImplicitBreaks + 1) ); } | |
116 | |
117 private: | |
118 LayoutUnit m_breakOffset; // Flow thread offset where this run ends. | |
119 unsigned m_assumedImplicitBreaks; // Number of implicit breaks in this r un assumed so far. | |
120 }; | |
121 Vector<ContentRun, 1> m_contentRuns; | |
122 }; | |
123 | |
124 } // namespace blink | |
125 | |
126 #endif // MultiColumnRow_h | |
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