Changeset 263597 in webkit

Timestamp:

Jun 26, 2020 4:26:54 PM (4 years ago)

Author:

Alan Bujtas

Message:

[LFC][BFC] Add support for <center>
​https://bugs.webkit.org/show_bug.cgi?id=213649

Reviewed by Antti Koivisto.

Source/WebCore:

Adjust the margin box to center the block content (this is very similar to [style="margin-left: auto; margin-right: auto;"]).

Test: fast/layoutformattingcontext/center-alignment-with-block-content-simple.html

• layout/blockformatting/BlockFormattingContextGeometry.cpp:

(WebCore::Layout::BlockFormattingContext::Geometry::inFlowNonReplacedWidthAndMargin):

LayoutTests:

• fast/layoutformattingcontext/center-alignment-with-block-content-simple-expected.html: Added.
• fast/layoutformattingcontext/center-alignment-with-block-content-simple.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/layoutformattingcontext/center-alignment-with-block-content-simple-expected.html (added)
• LayoutTests/fast/layoutformattingcontext/center-alignment-with-block-content-simple.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp (modified) (3 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2020-06-26  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][BFC] Add support for <center>
+        https://bugs.webkit.org/show_bug.cgi?id=213649
+
+        Reviewed by Antti Koivisto.
+
+        * fast/layoutformattingcontext/center-alignment-with-block-content-simple-expected.html: Added.
+        * fast/layoutformattingcontext/center-alignment-with-block-content-simple.html: Added.
+
 2020-06-26  Karl Rackler  <rackler@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2020-06-26  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][BFC] Add support for <center>
+        https://bugs.webkit.org/show_bug.cgi?id=213649
+
+        Reviewed by Antti Koivisto.
+
+        Adjust the margin box to center the block content (this is very similar to [style="margin-left: auto; margin-right: auto;"]).
+
+        Test: fast/layoutformattingcontext/center-alignment-with-block-content-simple.html
+
+        * layout/blockformatting/BlockFormattingContextGeometry.cpp:
+        (WebCore::Layout::BlockFormattingContext::Geometry::inFlowNonReplacedWidthAndMargin):
+
 2020-06-26  Jason Lawrence  <lawrence.j@apple.com>
 

trunk/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp

@@ -141 +141 @@
 
         auto containingBlockWidth = horizontalConstraints.logicalWidth;
+        auto& containingBlockStyle = layoutBox.containingBlock().style();
         auto& boxGeometry = formattingContext().geometryForBox(layoutBox);
 
@@ -160 +161 @@
         // #2
         if (width && computedHorizontalMargin.start && computedHorizontalMargin.end) {
-            if (layoutBox.containingBlock().style().isLeftToRightDirection()) {
+            if (containingBlockStyle.isLeftToRightDirection()) {
                 usedHorizontalMargin.start = *computedHorizontalMargin.start;
                 usedHorizontalMargin.end = containingBlockWidth - (usedHorizontalMargin.start + borderLeft + paddingLeft + *width + paddingRight + borderRight);
@@ -193 +194 @@
         }
 
+        auto shouldApplyCenterAlignForBlockContent = containingBlockStyle.textAlign() == TextAlignMode::WebKitCenter && (computedHorizontalMargin.start || computedHorizontalMargin.end);
+        if (shouldApplyCenterAlignForBlockContent) {
+            auto borderBoxWidth = (borderLeft + paddingLeft  + *width + paddingRight + borderRight);
+            auto marginStart = computedHorizontalMargin.start.valueOr(0);
+            auto marginEnd = computedHorizontalMargin.end.valueOr(0);
+            auto centeredLogicalLeftForMarginBox = std::max((containingBlockWidth - borderBoxWidth - marginStart - marginEnd) / 2, 0_lu);
+            usedHorizontalMargin.start = centeredLogicalLeftForMarginBox + marginStart;
+            usedHorizontalMargin.end = containingBlockWidth - borderBoxWidth - marginStart + marginEnd;
+        }
         ASSERT(width);