Changeset 267059 in webkit

Timestamp:

Sep 14, 2020 5:40:18 PM (4 years ago)

Author:

Alan Bujtas

Message:

[LFC][FFC] Block box flex items establish block formatting contexts
​https://bugs.webkit.org/show_bug.cgi?id=216502

Reviewed by Simon Fraser.

1. The display value of a flex item is blockified: if the specified display of an in-flow child of an element generating a flex container is an inline-level value, it computes to its block-level equivalent.
2. A block box that establishes an independent formatting context establishes a new block formatting context for its contents.

• layout/layouttree/LayoutBox.cpp:

(WebCore::Layout::Box::establishesBlockFormattingContext const):
(WebCore::Layout::Box::isBlockBox const):

• layout/layouttree/LayoutBox.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/layouttree/LayoutBox.cpp (modified) (6 diffs)
• layout/layouttree/LayoutBox.h (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2020-09-14  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][FFC] Block box flex items establish block formatting contexts
+        https://bugs.webkit.org/show_bug.cgi?id=216502
+
+        Reviewed by Simon Fraser.
+
+        1. The display value of a flex item is blockified: if the specified display of an in-flow child of an element
+           generating a flex container is an inline-level value, it computes to its block-level equivalent.
+        2. A block box that establishes an independent formatting context establishes a new block formatting context for its contents.
+
+        * layout/layouttree/LayoutBox.cpp:
+        (WebCore::Layout::Box::establishesBlockFormattingContext const):
+        (WebCore::Layout::Box::isBlockBox const):
+        * layout/layouttree/LayoutBox.h:
+
 2020-09-14  Jer Noble  <jer.noble@apple.com>
 

trunk/Source/WebCore/layout/layouttree/LayoutBox.cpp

@@ -82 +82 @@
         return true;
 
+    // A block box that establishes an independent formatting context establishes a new block formatting context for its contents.
+    if (isBlockBox() && establishesIndependentFormattingContext())
+        return true;
+
     // 9.4.1 Block formatting contexts
     // Floats, absolutely positioned elements, block containers (such as inline-blocks, table-cells, and table-captions)
     // that are not block boxes, and block boxes with 'overflow' other than 'visible' (except when that value has been propagated to the viewport)
     // establish new block formatting contexts for their contents.
-    if (isFloatingPositioned() || isAbsolutelyPositioned()) {
+    if (isFloatingPositioned()) {
         // Not all floating or out-of-positioned block level boxes establish BFC.
         // See [9.7 Relationships between 'display', 'position', and 'float'] for details.
@@ -92 +96 @@
     }
 
-    if (isBlockContainerBox() && !isBlockLevelBox())
+    if (isBlockContainer() && !isBlockLevelBox())
         return true;
 
@@ -105 +109 @@
     // 9.4.2 Inline formatting contexts
     // An inline formatting context is established by a block container box that contains no block-level boxes.
-    if (!isBlockContainerBox())
+    if (!isBlockContainer())
         return false;
 
@@ -205 +209 @@
         auto* ancestor = &parent();
         for (; !is<InitialContainingBlock>(*ancestor); ancestor = &ancestor->parent()) {
-            if (ancestor->isBlockContainerBox() || ancestor->establishesFormattingContext())
+            if (ancestor->isBlockContainer() || ancestor->establishesFormattingContext())
                 return *ancestor;
         }
@@ -295 +299 @@
 }
 
+bool Box::isBlockBox() const
+{
+    // A block-level box that is also a block container.
+    return isBlockLevelBox() && isBlockContainer();
+}
+
 bool Box::isInlineLevelBox() const
 {
@@ -322 +332 @@
 }
 
-bool Box::isBlockContainerBox() const
+bool Box::isBlockContainer() const
 {
     auto display = m_style.display();

trunk/Source/WebCore/layout/layouttree/LayoutBox.h

@@ -102 +102 @@
     bool isAnonymous() const { return m_isAnonymous; }
 
+    // Block level elements generate block level boxes.
     bool isBlockLevelBox() const;
+    // A block-level box that is also a block container.
+    bool isBlockBox() const;
+    // A block-level box is also a block container box unless it is a table box or the principal box of a replaced element.
+    bool isBlockContainer() const;
     bool isInlineLevelBox() const;
     bool isInlineBox() const;
@@ -108 +113 @@
     bool isInlineBlockBox() const;
     bool isInlineTableBox() const;
-    bool isBlockContainerBox() const;
     bool isInitialContainingBlock() const { return baseTypeFlags().contains(InitialContainingBlockFlag); }