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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef NGInlineLayoutAlgorithm_h | 5 #ifndef NGInlineLayoutAlgorithm_h |
6 #define NGInlineLayoutAlgorithm_h | 6 #define NGInlineLayoutAlgorithm_h |
7 | 7 |
8 #include "core/CoreExport.h" | 8 #include "core/CoreExport.h" |
9 #include "core/layout/ng/geometry/ng_logical_offset.h" | 9 #include "core/layout/ng/geometry/ng_logical_offset.h" |
10 #include "core/layout/ng/inline/ng_inline_box_state.h" | 10 #include "core/layout/ng/inline/ng_inline_box_state.h" |
11 #include "core/layout/ng/inline/ng_inline_break_token.h" | 11 #include "core/layout/ng/inline/ng_inline_break_token.h" |
| 12 #include "core/layout/ng/inline/ng_inline_item_result.h" |
12 #include "core/layout/ng/inline/ng_line_height_metrics.h" | 13 #include "core/layout/ng/inline/ng_line_height_metrics.h" |
13 #include "core/layout/ng/ng_constraint_space_builder.h" | 14 #include "core/layout/ng/ng_constraint_space_builder.h" |
14 #include "core/layout/ng/ng_fragment_builder.h" | 15 #include "core/layout/ng/ng_fragment_builder.h" |
15 #include "core/layout/ng/ng_layout_algorithm.h" | 16 #include "core/layout/ng/ng_layout_algorithm.h" |
16 #include "platform/fonts/FontBaseline.h" | 17 #include "platform/fonts/FontBaseline.h" |
17 #include "platform/heap/Handle.h" | 18 #include "platform/heap/Handle.h" |
18 #include "platform/wtf/Vector.h" | 19 #include "platform/wtf/Vector.h" |
19 | 20 |
20 namespace blink { | 21 namespace blink { |
21 | 22 |
22 class NGConstraintSpace; | 23 class NGConstraintSpace; |
23 class NGInlineBreakToken; | 24 class NGInlineBreakToken; |
24 class NGInlineNode; | 25 class NGInlineNode; |
25 class NGInlineItem; | 26 class NGInlineItem; |
26 class NGLineBoxFragmentBuilder; | 27 class NGLineBoxFragmentBuilder; |
27 class NGTextFragmentBuilder; | 28 class NGTextFragmentBuilder; |
28 | 29 |
29 // A class for inline layout (e.g. a <span> with no special style). | 30 // A class for inline layout (e.g. a <span> with no special style). |
30 // | 31 // |
31 // Uses NGLineBreaker to find break opportunities, and let it call back to | 32 // This class determines the position of NGInlineItem and build line boxes. |
32 // construct linebox fragments and its wrapper box fragment. | |
33 // | 33 // |
34 // From a line breaker, this class manages the current line as a range, |start| | 34 // Uses NGLineBreaker to find NGInlineItems to form a line. |
35 // and |end|. |end| can be extended multiple times before creating a line, | |
36 // usually until |!CanFitOnLine()|. |SetBreakOpportunity| can mark the last | |
37 // confirmed offset that can fit. | |
38 class CORE_EXPORT NGInlineLayoutAlgorithm final | 35 class CORE_EXPORT NGInlineLayoutAlgorithm final |
39 : public NGLayoutAlgorithm<NGInlineNode, NGInlineBreakToken> { | 36 : public NGLayoutAlgorithm<NGInlineNode, NGInlineBreakToken> { |
40 public: | 37 public: |
41 NGInlineLayoutAlgorithm(NGInlineNode*, | 38 NGInlineLayoutAlgorithm(NGInlineNode*, |
42 NGConstraintSpace*, | 39 NGConstraintSpace*, |
43 NGInlineBreakToken* = nullptr); | 40 NGInlineBreakToken* = nullptr); |
44 | 41 |
45 LayoutUnit MaxInlineSize() const { return max_inline_size_; } | 42 // The available width for the current line. |
| 43 LayoutUnit AvailableWidth() const; |
46 | 44 |
47 // Returns if the current items fit on a line. | 45 // Create a line. |
48 bool CanFitOnLine() const; | |
49 | |
50 // Returns if there were any items. | |
51 bool HasItems() const; | |
52 | |
53 // Set the end offset. | |
54 void SetEnd(unsigned end_offset); | |
55 | |
56 // Set the end offset if caller knows the inline size since the current end. | |
57 void SetEnd(unsigned index, | |
58 unsigned end_offset, | |
59 LayoutUnit inline_size_since_current_end); | |
60 | |
61 // Create a line up to the end offset. | |
62 // Then set the start to the end offset, and thus empty the current line. | |
63 // @return false if the line does not fit in the constraint space in block | 46 // @return false if the line does not fit in the constraint space in block |
64 // direction. | 47 // direction. |
65 bool CreateLine(); | 48 bool CreateLine(NGInlineItemResults*, RefPtr<NGInlineBreakToken> = nullptr); |
66 | |
67 // Returns if a break opportunity was set on the current line. | |
68 bool HasBreakOpportunity() const; | |
69 | |
70 // Returns if there were items after the last break opportunity. | |
71 bool HasItemsAfterLastBreakOpportunity() const; | |
72 | |
73 // Set the break opportunity at the current end offset. | |
74 void SetBreakOpportunity(); | |
75 | |
76 // Create a line up to the last break opportunity. | |
77 // Items after that are sent to the next line. | |
78 // @return false if the line does not fit in the constraint space in block | |
79 // direction. | |
80 bool CreateLineUpToLastBreakOpportunity(); | |
81 | |
82 // Set the start offset of hangables; e.g., spaces or hanging punctuations. | |
83 // Hangable characters can go beyond the right margin, and are ignored for | |
84 // center/right alignment. | |
85 void SetStartOfHangables(unsigned offset); | |
86 | 49 |
87 RefPtr<NGLayoutResult> Layout() override; | 50 RefPtr<NGLayoutResult> Layout() override; |
88 | 51 |
89 // Compute MinMaxContentSize by performing layout. | 52 // Lays out the inline float. |
90 // Unlike NGLayoutAlgorithm::ComputeMinMaxContentSize(), this function runs | 53 // List of actions: |
91 // part of layout operations and modifies the state of |this|. | 54 // - tries to position the float right away if we have enough space. |
92 MinMaxContentSize ComputeMinMaxContentSizeByLayout(); | 55 // - updates the current_opportunity if we actually place the float. |
93 | 56 // - if it's too wide then we add the float to the unpositioned list so it can |
94 // Compute inline size of an NGInlineItem. | 57 // be positioned after we're done with the current line. |
95 // Same as NGInlineItem::InlineSize(), except that this function can compute | 58 void LayoutAndPositionFloat(LayoutUnit end_position, LayoutObject*); |
96 // atomic inlines by performing layout. | |
97 LayoutUnit InlineSize(const NGInlineItem&); | |
98 | 59 |
99 private: | 60 private: |
100 bool IsHorizontalWritingMode() const { return is_horizontal_writing_mode_; } | 61 bool IsHorizontalWritingMode() const { return is_horizontal_writing_mode_; } |
101 | 62 |
102 bool IsFirstLine() const; | 63 bool IsFirstLine() const; |
103 const ComputedStyle& FirstLineStyle() const; | 64 const ComputedStyle& FirstLineStyle() const; |
104 const ComputedStyle& LineStyle() const; | 65 const ComputedStyle& LineStyle() const; |
105 | 66 |
106 // Set the start and the end to the specified offset. | 67 void BidiReorder(NGInlineItemResults*); |
107 // This empties the current line. | |
108 void Initialize(unsigned index, unsigned offset); | |
109 | 68 |
110 LayoutUnit InlineSize(const NGInlineItem&, | 69 bool PlaceItems(NGInlineItemResults*, RefPtr<NGInlineBreakToken>); |
111 unsigned start_offset, | |
112 unsigned end_offset); | |
113 LayoutUnit InlineSizeFromLayout(const NGInlineItem&); | |
114 const NGLayoutResult* LayoutItem(const NGInlineItem&); | |
115 | |
116 struct LineItemChunk { | |
117 unsigned index; | |
118 unsigned start_offset; | |
119 unsigned end_offset; | |
120 LayoutUnit inline_size; | |
121 }; | |
122 | |
123 void BidiReorder(Vector<LineItemChunk, 32>*); | |
124 | |
125 // Lays out the inline float. | |
126 // List of actions: | |
127 // - tries to position the float right away if we have enough space. | |
128 // - updates the current_opportunity if we actually place the float. | |
129 // - if it's too wide then we add the float to the unpositioned list so it can | |
130 // be positioned after we're done with the current line. | |
131 void LayoutAndPositionFloat(LayoutUnit end_position, LayoutObject*); | |
132 | |
133 bool PlaceItems(const Vector<LineItemChunk, 32>&); | |
134 void AccumulateUsedFonts(const NGInlineItem&, | |
135 const LineItemChunk&, | |
136 NGLineBoxFragmentBuilder*); | |
137 LayoutUnit PlaceAtomicInline(const NGInlineItem&, | 70 LayoutUnit PlaceAtomicInline(const NGInlineItem&, |
| 71 NGInlineItemResult*, |
138 NGLineBoxFragmentBuilder*, | 72 NGLineBoxFragmentBuilder*, |
139 NGInlineBoxState*, | 73 NGInlineBoxState*, |
140 NGTextFragmentBuilder*); | 74 NGTextFragmentBuilder*); |
141 | 75 |
142 // Finds the next layout opportunity for the next text fragment. | 76 // Finds the next layout opportunity for the next text fragment. |
143 void FindNextLayoutOpportunity(); | 77 void FindNextLayoutOpportunity(); |
144 | 78 |
145 Vector<RefPtr<NGLayoutResult>, 32> layout_results_; | |
146 NGInlineLayoutStateStack box_states_; | 79 NGInlineLayoutStateStack box_states_; |
147 unsigned start_index_ = 0; | |
148 unsigned start_offset_ = 0; | |
149 unsigned last_index_ = 0; | |
150 unsigned end_offset_ = 0; | |
151 unsigned last_break_opportunity_index_ = 0; | |
152 unsigned last_break_opportunity_offset_ = 0; | |
153 LayoutUnit end_position_; | |
154 LayoutUnit last_break_opportunity_position_; | |
155 LayoutUnit content_size_; | 80 LayoutUnit content_size_; |
156 LayoutUnit max_inline_size_; | 81 LayoutUnit max_inline_size_; |
157 FontBaseline baseline_type_ = FontBaseline::kAlphabeticBaseline; | 82 FontBaseline baseline_type_ = FontBaseline::kAlphabeticBaseline; |
158 | 83 |
159 NGLogicalOffset bfc_offset_; | 84 NGLogicalOffset bfc_offset_; |
160 NGLogicalRect current_opportunity_; | 85 NGLogicalRect current_opportunity_; |
161 | 86 |
162 unsigned is_horizontal_writing_mode_ : 1; | 87 unsigned is_horizontal_writing_mode_ : 1; |
163 unsigned disallow_first_line_rules_ : 1; | 88 unsigned disallow_first_line_rules_ : 1; |
164 | 89 |
165 NGConstraintSpaceBuilder space_builder_; | 90 NGConstraintSpaceBuilder space_builder_; |
166 #if DCHECK_IS_ON() | |
167 unsigned is_bidi_reordered_ : 1; | |
168 #endif | |
169 }; | 91 }; |
170 | 92 |
171 } // namespace blink | 93 } // namespace blink |
172 | 94 |
173 #endif // NGInlineLayoutAlgorithm_h | 95 #endif // NGInlineLayoutAlgorithm_h |
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