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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 NGBlockLayoutAlgorithm_h | 5 #ifndef NGBlockLayoutAlgorithm_h |
6 #define NGBlockLayoutAlgorithm_h | 6 #define NGBlockLayoutAlgorithm_h |
7 | 7 |
8 #include "core/CoreExport.h" | 8 #include "core/CoreExport.h" |
9 #include "core/layout/ng/geometry/ng_margin_strut.h" | 9 #include "core/layout/ng/geometry/ng_margin_strut.h" |
10 #include "core/layout/ng/ng_block_break_token.h" | 10 #include "core/layout/ng/ng_block_break_token.h" |
11 #include "core/layout/ng/ng_block_node.h" | 11 #include "core/layout/ng/ng_block_node.h" |
| 12 #include "core/layout/ng/ng_box_fragment.h" |
12 #include "core/layout/ng/ng_constraint_space_builder.h" | 13 #include "core/layout/ng/ng_constraint_space_builder.h" |
13 #include "core/layout/ng/ng_layout_algorithm.h" | 14 #include "core/layout/ng/ng_layout_algorithm.h" |
14 #include "platform/wtf/RefPtr.h" | 15 #include "platform/wtf/RefPtr.h" |
15 | 16 |
16 namespace blink { | 17 namespace blink { |
17 | 18 |
18 class NGConstraintSpace; | 19 class NGConstraintSpace; |
19 class NGLayoutResult; | 20 class NGLayoutResult; |
20 | 21 |
21 // Updates the fragment's BFC offset if it's not already set. | 22 // Updates the fragment's BFC offset if it's not already set. |
22 void MaybeUpdateFragmentBfcOffset(const NGConstraintSpace&, | 23 void MaybeUpdateFragmentBfcOffset(const NGConstraintSpace&, |
23 const NGLogicalOffset&, | 24 const NGLogicalOffset&, |
24 NGFragmentBuilder* builder); | 25 NGFragmentBuilder* builder); |
25 | 26 |
| 27 // Positions pending floats starting from {@origin_block_offset} and relative |
| 28 // to container's BFC offset. |
| 29 void PositionPendingFloats(LayoutUnit origin_block_offset, |
| 30 NGFragmentBuilder* container_builder, |
| 31 NGConstraintSpace* space); |
| 32 |
26 // A class for general block layout (e.g. a <div> with no special style). | 33 // A class for general block layout (e.g. a <div> with no special style). |
27 // Lays out the children in sequence. | 34 // Lays out the children in sequence. |
28 class CORE_EXPORT NGBlockLayoutAlgorithm | 35 class CORE_EXPORT NGBlockLayoutAlgorithm |
29 : public NGLayoutAlgorithm<NGBlockNode, NGBlockBreakToken> { | 36 : public NGLayoutAlgorithm<NGBlockNode, NGBlockBreakToken> { |
30 public: | 37 public: |
31 // Default constructor. | 38 // Default constructor. |
32 // @param node The input node to perform layout upon. | 39 // @param node The input node to perform layout upon. |
33 // @param space The constraint space which the algorithm should generate a | 40 // @param space The constraint space which the algorithm should generate a |
34 // fragment within. | 41 // fragment within. |
35 // @param break_token The break token from which the layout should start. | 42 // @param break_token The break token from which the layout should start. |
36 NGBlockLayoutAlgorithm(NGBlockNode* node, | 43 NGBlockLayoutAlgorithm(NGBlockNode* node, |
37 NGConstraintSpace* space, | 44 NGConstraintSpace* space, |
38 NGBlockBreakToken* break_token = nullptr); | 45 NGBlockBreakToken* break_token = nullptr); |
39 | 46 |
40 Optional<MinMaxContentSize> ComputeMinMaxContentSize() const override; | 47 Optional<MinMaxContentSize> ComputeMinMaxContentSize() const override; |
41 virtual RefPtr<NGLayoutResult> Layout() override; | 48 virtual RefPtr<NGLayoutResult> Layout() override; |
42 | 49 |
43 private: | 50 private: |
44 NGBoxStrut CalculateMargins(NGLayoutInputNode* child, | 51 NGBoxStrut CalculateMargins(NGLayoutInputNode* child, |
45 const NGConstraintSpace& space); | 52 const NGConstraintSpace& space); |
46 | 53 |
47 // Creates a new constraint space for the current child. | 54 // Creates a new constraint space for the current child. |
48 RefPtr<NGConstraintSpace> CreateConstraintSpaceForChild(NGLayoutInputNode*); | 55 RefPtr<NGConstraintSpace> CreateConstraintSpaceForChild( |
49 void PrepareChildLayout(NGLayoutInputNode*); | 56 const NGLogicalOffset& child_bfc_offset, |
50 void FinishChildLayout(NGLayoutInputNode*, | 57 NGLayoutInputNode*); |
51 NGConstraintSpace*, | 58 |
52 RefPtr<NGLayoutResult>); | 59 // @return Estimated BFC offset for the "to be layout" child. |
| 60 NGLogicalOffset PrepareChildLayout(NGLayoutInputNode*); |
| 61 |
| 62 void FinishChildLayout(const NGConstraintSpace*, NGLayoutResult*); |
| 63 |
| 64 // Positions the fragment that establishes a new formatting context. |
| 65 // |
| 66 // This uses Layout Opportunity iterator to position the fragment. |
| 67 // That's because an element that establishes a new block formatting context |
| 68 // must not overlap the margin box of any floats in the same block formatting |
| 69 // context as the element itself. |
| 70 // |
| 71 // So if necessary, we clear the new BFC by placing it below any preceding |
| 72 // floats or place it adjacent to such floats if there is sufficient space. |
| 73 // |
| 74 // Example: |
| 75 // <div id="container"> |
| 76 // <div id="float"></div> |
| 77 // <div id="new-fc" style="margin-top: 20px;"></div> |
| 78 // </div> |
| 79 // 1) If #new-fc is small enough to fit the available space right from #float |
| 80 // then it will be placed there and we collapse its margin. |
| 81 // 2) If #new-fc is too big then we need to clear its position and place it |
| 82 // below #float ignoring its vertical margin. |
| 83 NGLogicalOffset PositionNewFc(const NGBoxFragment&, |
| 84 const NGConstraintSpace& child_space); |
| 85 |
| 86 // Positions the fragment that knows its BFC offset. |
| 87 NGLogicalOffset PositionWithBfcOffset(const NGBoxFragment&); |
| 88 |
| 89 // Positions using the parent BFC offset. |
| 90 // Fragment doesn't know its offset but we can still calculate its BFC |
| 91 // position because the parent fragment's BFC is known. |
| 92 // Example: |
| 93 // BFC Offset is known here because of the padding. |
| 94 // <div style="padding: 1px"> |
| 95 // <div id="empty-div" style="margins: 1px"></div> |
| 96 NGLogicalOffset PositionWithParentBfc(); |
| 97 |
| 98 void FinishFloatChildLayout(const ComputedStyle&, |
| 99 const NGConstraintSpace&, |
| 100 const NGLayoutResult*); |
53 | 101 |
54 // Final adjustments before fragment creation. We need to prevent the | 102 // Final adjustments before fragment creation. We need to prevent the |
55 // fragment from crossing fragmentainer boundaries, and rather create a break | 103 // fragment from crossing fragmentainer boundaries, and rather create a break |
56 // token if we're out of space. | 104 // token if we're out of space. |
57 void FinalizeForFragmentation(); | 105 void FinalizeForFragmentation(); |
58 | 106 |
59 // Calculates logical offset for the current fragment using either | 107 // Calculates logical offset for the current fragment using either |
60 // {@code content_size_} when the fragment doesn't know it's offset | 108 // {@code content_size_} when the fragment doesn't know it's offset |
61 // or {@code known_fragment_offset} if the fragment knows it's offset | 109 // or {@code known_fragment_offset} if the fragment knows it's offset |
62 // @return Fragment's offset relative to the fragment's parent. | 110 // @return Fragment's offset relative to the fragment's parent. |
63 NGLogicalOffset CalculateLogicalOffset( | 111 NGLogicalOffset CalculateLogicalOffset( |
64 const WTF::Optional<NGLogicalOffset>& known_fragment_offset); | 112 const WTF::Optional<NGLogicalOffset>& known_fragment_offset); |
65 | 113 |
66 NGConstraintSpaceBuilder space_builder_; | 114 NGConstraintSpaceBuilder space_builder_; |
67 | 115 |
68 NGBoxStrut border_and_padding_; | 116 NGBoxStrut border_and_padding_; |
69 LayoutUnit content_size_; | 117 LayoutUnit content_size_; |
70 LayoutUnit max_inline_size_; | 118 LayoutUnit max_inline_size_; |
71 // MarginStrut for the previous child. | 119 // MarginStrut for the previous child. |
72 NGMarginStrut curr_margin_strut_; | 120 NGMarginStrut curr_margin_strut_; |
73 NGLogicalOffset curr_bfc_offset_; | 121 NGLogicalOffset curr_bfc_offset_; |
74 NGBoxStrut curr_child_margins_; | 122 NGBoxStrut curr_child_margins_; |
75 }; | 123 }; |
76 | 124 |
77 } // namespace blink | 125 } // namespace blink |
78 | 126 |
79 #endif // NGBlockLayoutAlgorithm_h | 127 #endif // NGBlockLayoutAlgorithm_h |
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