Changeset 276548 in webkit

Timestamp:

Apr 24, 2021, 6:10:44 AM (5 years ago)

Author:

Alan Bujtas

Message:

[LFC] Ignore content height and width when 'contain: size' is present
​https://bugs.webkit.org/show_bug.cgi?id=225013

Reviewed by Antti Koivisto.

Enable size containment for "shrink to fit width" and for "height: auto" formatting context roots.
​https://www.w3.org/TR/css-contain-2/#size-containment.

• layout/FormattingContextGeometry.cpp:

(WebCore::Layout::FormattingContext::Geometry::contentHeightForFormattingContextRoot const):
(WebCore::Layout::FormattingContext::Geometry::shrinkToFitWidth):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/FormattingContextGeometry.cpp (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-04-24  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC] Ignore content height and width when 'contain: size' is present
+        https://bugs.webkit.org/show_bug.cgi?id=225013
+
+        Reviewed by Antti Koivisto.
+
+        Enable size containment for "shrink to fit width" and for "height: auto" formatting context roots.    
+        https://www.w3.org/TR/css-contain-2/#size-containment.
+
+        * layout/FormattingContextGeometry.cpp:
+        (WebCore::Layout::FormattingContext::Geometry::contentHeightForFormattingContextRoot const):
+        (WebCore::Layout::FormattingContext::Geometry::shrinkToFitWidth):
+
 2021-04-24  Rob Buis  <rbuis@igalia.com>
 

trunk/Source/WebCore/layout/FormattingContextGeometry.cpp

@@ -176 +176 @@
     ASSERT(formattingContextRoot.establishesFormattingContext());
     ASSERT(isHeightAuto(formattingContextRoot) || formattingContextRoot.establishesTableFormattingContext() || formattingContextRoot.isTableCell());
-    if (!formattingContextRoot.hasInFlowOrFloatingChild())
-        return { };
-    return LayoutContext::createFormattingContext(formattingContextRoot, const_cast<LayoutState&>(layoutState()))->usedContentHeight();
+    auto usedContentHeight = LayoutUnit { }; 
+    auto hasContent = formattingContextRoot.hasInFlowOrFloatingChild();
+    // The used height of the containment box is determined as if performing a normal layout of the box, except that it is treated as having no content.
+    auto shouldIgnoreContent = formattingContextRoot.isSizeContainmentBox();
+    if (hasContent && !shouldIgnoreContent)
+        usedContentHeight = LayoutContext::createFormattingContext(formattingContextRoot, const_cast<LayoutState&>(layoutState()))->usedContentHeight();
+    return usedContentHeight;
 }
 
@@ -279 +283 @@
 }
 
-LayoutUnit FormattingContext::Geometry::shrinkToFitWidth(const Box& formattingRoot, LayoutUnit availableWidth)
-{
-    LOG_WITH_STREAM(FormattingContextLayout, stream << "[Width] -> shrink to fit -> unsupported -> width(" << LayoutUnit { } << "px) layoutBox: " << &formattingRoot << ")");
-    ASSERT(formattingRoot.establishesFormattingContext());
+LayoutUnit FormattingContext::Geometry::shrinkToFitWidth(const Box& formattingContextRoot, LayoutUnit availableWidth)
+{
+    LOG_WITH_STREAM(FormattingContextLayout, stream << "[Width] -> shrink to fit -> unsupported -> width(" << LayoutUnit { } << "px) layoutBox: " << &formattingContextRoot << ")");
+    ASSERT(formattingContextRoot.establishesFormattingContext());
 
     // Calculation of the shrink-to-fit width is similar to calculating the width of a table cell using the automatic table layout algorithm.
@@ -292 +296 @@
     // Then the shrink-to-fit width is: min(max(preferred minimum width, available width), preferred width).
     auto intrinsicWidthConstraints = IntrinsicWidthConstraints { };
-    if (is<ContainerBox>(formattingRoot) && downcast<ContainerBox>(formattingRoot).hasInFlowOrFloatingChild()) {
-        auto& root = downcast<ContainerBox>(formattingRoot);
+    auto hasContent = is<ContainerBox>(formattingContextRoot) && downcast<ContainerBox>(formattingContextRoot).hasInFlowOrFloatingChild();
+    // The used width of the containment box is determined as if performing a normal layout of the box, except that it is treated as having no content.
+    auto shouldIgnoreContent = formattingContextRoot.isSizeContainmentBox();  
+    if (hasContent && !shouldIgnoreContent) {
+        auto& root = downcast<ContainerBox>(formattingContextRoot);
         auto& formattingStateForRoot = layoutState().ensureFormattingState(root);
         auto precomputedIntrinsicWidthConstraints = formattingStateForRoot.intrinsicWidthConstraints();