Index: third_party/WebKit/Source/core/layout/ng/ng_relative_utils.cc |
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_relative_utils.cc b/third_party/WebKit/Source/core/layout/ng/ng_relative_utils.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..8778e2e17e37c51e678f5c462c5be89a229df435 |
--- /dev/null |
+++ b/third_party/WebKit/Source/core/layout/ng/ng_relative_utils.cc |
@@ -0,0 +1,78 @@ |
+// Copyright 2017 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "core/layout/ng/ng_relative_utils.h" |
+ |
+#include "core/layout/ng/geometry/ng_logical_offset.h" |
+#include "core/layout/ng/geometry/ng_physical_size.h" |
+#include "core/style/ComputedStyle.h" |
+#include "platform/LengthFunctions.h" |
+#include "wtf/Optional.h" |
+ |
+namespace blink { |
+ |
+// Returns the child's relative position wrt the containing fragment. |
+NGLogicalOffset ComputeRelativeOffset(const ComputedStyle& child_style, |
+ NGWritingMode container_writing_mode, |
+ TextDirection container_direction, |
+ NGLogicalSize container_logical_size) { |
+ NGLogicalOffset offset; |
+ NGPhysicalSize container_size = |
+ container_logical_size.ConvertToPhysical(container_writing_mode); |
+ |
+ Optional<LayoutUnit> left, right, top, bottom; |
+ |
+ if (!child_style.left().isAuto()) |
+ left = valueForLength(child_style.left(), container_size.width); |
+ if (!child_style.right().isAuto()) |
+ right = valueForLength(child_style.right(), container_size.width); |
+ if (!child_style.top().isAuto()) |
+ top = valueForLength(child_style.top(), container_size.height); |
+ if (!child_style.bottom().isAuto()) |
+ bottom = valueForLength(child_style.bottom(), container_size.height); |
+ |
+ // Implements confict resolution rules from spec: |
+ // https://www.w3.org/TR/css-position-3/#rel-pos |
+ if (!left && !right) { |
+ left = LayoutUnit(); |
+ right = LayoutUnit(); |
+ } |
+ if (!left) |
+ left = -right.value(); |
+ if (!right) |
+ right = -left.value(); |
+ if (!top && !bottom) { |
+ top = LayoutUnit(); |
+ bottom = LayoutUnit(); |
+ } |
+ if (!top) |
+ top = -bottom.value(); |
+ if (!bottom) |
+ bottom = -top.value(); |
+ |
+ bool is_ltr = container_direction == TextDirection::kLtr; |
+ |
+ switch (container_writing_mode) { |
+ case kHorizontalTopBottom: |
+ offset.inline_offset = is_ltr ? left.value() : right.value(); |
+ offset.block_offset = top.value(); |
+ break; |
+ case kVerticalRightLeft: |
+ case kSidewaysRightLeft: |
+ offset.inline_offset = is_ltr ? top.value() : bottom.value(); |
+ offset.block_offset = right.value(); |
+ break; |
+ case kVerticalLeftRight: |
+ offset.inline_offset = is_ltr ? top.value() : bottom.value(); |
+ offset.block_offset = left.value(); |
+ break; |
+ case kSidewaysLeftRight: |
+ offset.inline_offset = is_ltr ? bottom.value() : top.value(); |
+ offset.block_offset = left.value(); |
+ break; |
+ } |
+ return offset; |
+} |
+ |
+} // namespace blink |