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1 // Copyright 2017 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 #include "core/layout/ng/ng_relative_utils.h" | |
6 | |
7 #include "core/layout/ng/geometry/ng_logical_offset.h" | |
8 #include "core/layout/ng/geometry/ng_physical_size.h" | |
9 #include "core/style/ComputedStyle.h" | |
10 #include "platform/LengthFunctions.h" | |
11 #include "wtf/Optional.h" | |
12 | |
13 namespace blink { | |
14 | |
15 // Returns child's relative position wrt containing fragment. | |
ikilpatrick
2017/03/21 17:51:17
"Returns the child's relative position wrt the con
atotic
2017/03/21 19:13:54
done.
| |
16 NGLogicalOffset ComputeRelativeOffset(const ComputedStyle& child_style, | |
17 NGWritingMode container_writing_mode, | |
18 TextDirection container_direction, | |
19 NGLogicalSize container_logical_size) { | |
20 NGLogicalOffset offset; | |
21 NGPhysicalSize container_size = | |
22 container_logical_size.ConvertToPhysical(container_writing_mode); | |
23 | |
24 Optional<LayoutUnit> left, right, top, bottom; | |
25 | |
26 if (!child_style.left().isAuto()) | |
27 left = valueForLength(child_style.left(), container_size.width); | |
28 if (!child_style.right().isAuto()) | |
29 right = valueForLength(child_style.right(), container_size.width); | |
30 if (!child_style.top().isAuto()) | |
31 top = valueForLength(child_style.top(), container_size.height); | |
32 if (!child_style.bottom().isAuto()) | |
33 bottom = valueForLength(child_style.bottom(), container_size.height); | |
34 | |
35 // Implements confict resolution rules from spec: | |
36 // https://www.w3.org/TR/css-position-3/#rel-pos | |
37 if (!left && !right) { | |
38 left = LayoutUnit(); | |
39 right = LayoutUnit(); | |
40 } | |
41 if (!left) | |
42 left = -right.value(); | |
43 if (!right) | |
44 right = -left.value(); | |
45 if (!top && !bottom) { | |
46 top = LayoutUnit(); | |
47 bottom = LayoutUnit(); | |
48 } | |
49 if (!top) | |
50 top = -bottom.value(); | |
51 if (!bottom) | |
52 bottom = -top.value(); | |
53 | |
54 bool is_ltr = container_direction == TextDirection::kLtr; | |
55 | |
56 switch (container_writing_mode) { | |
57 case kHorizontalTopBottom: | |
58 offset.inline_offset = is_ltr ? left.value() : right.value(); | |
59 offset.block_offset = top.value(); | |
60 break; | |
61 case kVerticalRightLeft: | |
62 case kSidewaysRightLeft: | |
63 offset.inline_offset = is_ltr ? top.value() : bottom.value(); | |
64 offset.block_offset = right.value(); | |
65 break; | |
66 case kVerticalLeftRight: | |
67 offset.inline_offset = is_ltr ? top.value() : bottom.value(); | |
68 offset.block_offset = left.value(); | |
69 break; | |
70 case kSidewaysLeftRight: | |
71 offset.inline_offset = is_ltr ? bottom.value() : top.value(); | |
72 offset.block_offset = left.value(); | |
73 break; | |
74 } | |
75 return offset; | |
76 } | |
77 | |
78 } // namespace blink | |
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