Attachment 356355 Details for Bug 192297 – Patch

[patch] Patch

bug-192297-20181202214137.patch (text/plain), 3.65 KB, created by zalan on 2018-12-02 21:41:45 PST

(hide)

Description:

Filename:

MIME Type:

Creator: zalan

Created: 2018-12-02 21:41:45 PST

Size: 3.65 KB

patch

obsolete

>Subversion Revision: 238791
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index d1ac56ff4ac01acd15196428b65162054f0bb8b9..6d9eef69724465118477c3369876cf3091cc39a5 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,17 @@
>+2018-12-02  Zalan Bujtas  <zalan@apple.com>
>+
>+        [LFC][BFC][MarginCollapsing] Add MarginCollapse::establishesBlockFormattingContext
>+        https://bugs.webkit.org/show_bug.cgi?id=192297
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        WebKit treats the document element renderer as a block formatting context root. 
>+
>+        * layout/blockformatting/BlockMarginCollapse.cpp:
>+        (WebCore::Layout::establishesBlockFormattingContext):
>+        (WebCore::Layout::BlockFormattingContext::Geometry::MarginCollapse::isMarginTopCollapsedWithParent):
>+        (WebCore::Layout::BlockFormattingContext::Geometry::MarginCollapse::isMarginBottomCollapsedWithParent):
>+
> 2018-12-02  Zalan Bujtas  <zalan@apple.com>
> 
>         Add a runtime feature flag for LayoutFormattingContext.
>diff --git a/Source/WebCore/layout/blockformatting/BlockMarginCollapse.cpp b/Source/WebCore/layout/blockformatting/BlockMarginCollapse.cpp
>index eb793b3cd4f06dbee597da8b445b67903d407c21..bf1a08ccb659e5735937c76e822e87dba889e486 100644
>--- a/Source/WebCore/layout/blockformatting/BlockMarginCollapse.cpp
>+++ b/Source/WebCore/layout/blockformatting/BlockMarginCollapse.cpp
>@@ -69,6 +69,15 @@ static bool hasPaddingAfter(const Box& layoutBox)
>     return hasPadding(layoutBox.style().paddingAfter());
> }
> 
>+static bool establishesBlockFormattingContext(const Box& layoutBox)
>+{
>+    // WebKit treats the document element renderer as a block formatting context root. It probably only impacts margin collapsing, so let's not do
>+    // a layout wide quirk on this for now.
>+    if (layoutBox.isDocumentBox())
>+        return true;
>+    return layoutBox.establishesBlockFormattingContext();
>+}
>+
> static LayoutUnit marginValue(LayoutUnit currentMarginValue, LayoutUnit candidateMarginValue)
> {
>     if (!candidateMarginValue)
>@@ -131,14 +140,9 @@ bool BlockFormattingContext::Geometry::MarginCollapse::isMarginTopCollapsedWithP
>     if (layoutBox.previousInFlowSibling())
>         return false;
> 
>-    // We never margin collapse the initial containing block.
>-    ASSERT(layoutBox.parent());
>     auto& parent = *layoutBox.parent();
>-    if (parent.establishesBlockFormattingContext())
>-        return false;
>-
>-    // Margins of the root element's box do not collapse.
>-    if (parent.isDocumentBox() || parent.isInitialContainingBlock())
>+    // Margins of elements that establish new block formatting contexts do not collapse with their in-flow children
>+    if (establishesBlockFormattingContext(parent))
>         return false;
> 
>     if (hasBorderBefore(parent))
>@@ -308,18 +312,13 @@ bool BlockFormattingContext::Geometry::MarginCollapse::isMarginBottomCollapsedWi
>     if (isMarginBottomCollapsedThrough(layoutBox))
>         return false;
> 
>-    // We never margin collapse the initial containing block.
>-    ASSERT(layoutBox.parent());
>-    auto& parent = *layoutBox.parent();
>     // Only the last inlflow child collapses with parent.
>     if (layoutBox.nextInFlowSibling())
>         return false;
> 
>-    if (parent.establishesBlockFormattingContext())
>-        return false;
>-
>-    // Margins of the root element's box do not collapse.
>-    if (parent.isDocumentBox() || parent.isInitialContainingBlock())
>+    auto& parent = *layoutBox.parent();
>+    // Margins of elements that establish new block formatting contexts do not collapse with their in-flow children
>+    if (establishesBlockFormattingContext(parent))
>         return false;
> 
>     if (hasBorderBefore(parent))

Flags:

koivisto: review+

Actions: View | Formatted Diff | Diff

Attachments on bug 192297: 356355