[IFC][Line clamp] Add basic line-clamp implementation for IFC

https://bugs.webkit.org/show_bug.cgi?id=248160 Reviewed by Antti Koivisto. 1. Check if the deprecated flexbox subtree supports IFC 2. Run layout with line-clamp values set * Source/WebCore/layout/formattingContexts/inline/InlineFormattingContext.cpp: (WebCore::Layout::shouldTruncateOverflow): fix ordering. * Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp: (WebCore::RenderDeprecatedFlexibleBox::applyModernLineClamp): (WebCore::RenderDeprecatedFlexibleBox::applyLineClamp): * Source/WebCore/rendering/RenderDeprecatedFlexibleBox.h: * Source/WebCore/rendering/RenderLayoutState.h: (WebCore::RenderLayoutState::resetLineClamp): Canonical link: https://commits.webkit.org/256906@main
WebKit · Nov 21, 2022 · b360263 · b360263
1 parent 16b1006
commit b360263
Show file tree

Hide file tree

Showing 4 changed files with 65 additions and 6 deletions.
diff --git a/Source/WebCore/layout/formattingContexts/inline/InlineFormattingContext.cpp b/Source/WebCore/layout/formattingContexts/inline/InlineFormattingContext.cpp
@@ -209,18 +209,16 @@ enum class ShouldLineEndWithEllispsis : uint8_t {
 };
 static ShouldLineEndWithEllispsis shouldTruncateOverflow(const RenderStyle& rootStyle, size_t numberOfLines, std::optional<size_t> maximumNumberOfLines)
 {
-    // Truncation is in effect when the block container has overflow other than visible.
-    if (rootStyle.isOverflowVisible())
-        return ShouldLineEndWithEllispsis::No;
-    if (rootStyle.textOverflow() == TextOverflow::Ellipsis)
-        return ShouldLineEndWithEllispsis::WhenContentOverflows;
     if (maximumNumberOfLines) {
         ASSERT(numberOfLines < *maximumNumberOfLines);
         // If the next call to layoutInlineContent() won't produce a line with content (e.g. only floats), we'll end up here again.
         auto treatNextLineAsLastLine = *maximumNumberOfLines - numberOfLines == 1;
         if (treatNextLineAsLastLine)
             return ShouldLineEndWithEllispsis::Always;
     }
+    // Truncation is in effect when the block container has overflow other than visible.
+    if (!rootStyle.isOverflowVisible() && rootStyle.textOverflow() == TextOverflow::Ellipsis)
+        return ShouldLineEndWithEllispsis::WhenContentOverflows;
     return ShouldLineEndWithEllispsis::No;
 }
 

diff --git a/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp b/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.cpp
@@ -27,11 +27,13 @@
 
 #include "FontCascade.h"
 #include "LayoutRepainter.h"
+#include "RenderDescendantIterator.h"
 #include "RenderIterator.h"
 #include "RenderLayer.h"
 #include "RenderLayoutState.h"
 #include "RenderView.h"
 #include <wtf/IsoMallocInlines.h>
+#include <wtf/Scope.h>
 #include <wtf/StdLibExtras.h>
 #include <wtf/unicode/CharacterNames.h>
 
@@ -1019,9 +1021,50 @@ static size_t lineCountFor(const RenderBlockFlow& blockFlow)
     return count;
 }
 
+bool RenderDeprecatedFlexibleBox::applyModernLineClamp(FlexBoxIterator& iterator)
+{
+    auto* firstFlowBlockWithInlineChildren = [&] () -> RenderBlockFlow* {
+        for (auto& descendant : descendantsOfType<RenderBlockFlow>(*this)) {
+            if (descendant.childrenInline())
+                return &descendant;
+        }
+        return nullptr;
+    }();
+    if (!firstFlowBlockWithInlineChildren)
+        return false;
+
+    // If the first block with inline content supports modern line layout, all siblings (and descendants) do as well.
+    // see LayoutIntegrationCoverage::canUseForStyle.
+    firstFlowBlockWithInlineChildren->computeAndSetLineLayoutPath();
+    if (firstFlowBlockWithInlineChildren->lineLayoutPath() != RenderBlockFlow::ModernPath)
+        return false;
+
+    auto& layoutState = *view().frameView().layoutContext().layoutState();
+    auto currentLineClamp = std::optional<std::pair<size_t, size_t>> { };
+    if (layoutState.hasLineClamp())
+        currentLineClamp = { *layoutState.maximumLineCountForLineClamp(), layoutState.visibleLineCountForLineClamp().value_or(0) };
+
+    auto restoreCurrentLineClamp = makeScopeExit([&] {
+        if (!currentLineClamp)
+            return layoutState.resetLineClamp();
+        layoutState.setMaximumLineCountForLineClamp(currentLineClamp->first);
+        layoutState.setVisibleLineCountForLineClamp(currentLineClamp->second);
+    });
+
+    // FIXME: Add support for percent values.
+    layoutState.setMaximumLineCountForLineClamp(style().lineClamp().value());
+    layoutState.setVisibleLineCountForLineClamp({ });
+    for (auto* child = iterator.first(); child; child = iterator.next()) {
+        if (childDoesNotAffectWidthOrFlexing(child))
+            continue;
+
+        child->layoutIfNeeded();
+    }
+    return true;
+}
+
 void RenderDeprecatedFlexibleBox::applyLineClamp(FlexBoxIterator& iterator, bool relayoutChildren)
 {
-    size_t maxLineCount = 0;
     for (RenderBox* child = iterator.first(); child; child = iterator.next()) {
         if (childDoesNotAffectWidthOrFlexing(child))
             continue;
@@ -1037,6 +1080,16 @@ void RenderDeprecatedFlexibleBox::applyLineClamp(FlexBoxIterator& iterator, bool
                 clearTruncation(downcast<RenderBlockFlow>(*child));
             }
         }
+    }
+
+    if (applyModernLineClamp(iterator))
+        return;
+
+    size_t maxLineCount = 0;
+    for (RenderBox* child = iterator.first(); child; child = iterator.next()) {
+        if (childDoesNotAffectWidthOrFlexing(child))
+            continue;
+
         child->layoutIfNeeded();
         if (child->style().height().isAuto() && is<RenderBlockFlow>(*child))
             maxLineCount = std::max(maxLineCount, lineCountFor(downcast<RenderBlockFlow>(*child)));

diff --git a/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.h b/Source/WebCore/rendering/RenderDeprecatedFlexibleBox.h
@@ -63,6 +63,7 @@ class RenderDeprecatedFlexibleBox final : public RenderBlock {
     bool isHorizontal() const { return style().boxOrient() == BoxOrient::Horizontal; }
 
     void applyLineClamp(FlexBoxIterator&, bool relayoutChildren);
+    bool applyModernLineClamp(FlexBoxIterator&);
     void clearLineClamp();
 
     bool m_stretchingChildren;

diff --git a/Source/WebCore/rendering/RenderLayoutState.h b/Source/WebCore/rendering/RenderLayoutState.h
@@ -89,6 +89,7 @@ class RenderLayoutState {
 #endif
 
     bool hasLineClamp() const { return m_maximumLineCountForLineClamp.has_value(); }
+    void resetLineClamp();
     void setMaximumLineCountForLineClamp(size_t maximumLineCount) { m_maximumLineCountForLineClamp = maximumLineCount; }
     std::optional<size_t> maximumLineCountForLineClamp() { return m_maximumLineCountForLineClamp; }
     void setVisibleLineCountForLineClamp(size_t visibleLineCount) { m_visibleLineCountForLineClamp = visibleLineCount; }
@@ -184,4 +185,10 @@ class PaginatedLayoutStateMaintainer {
     bool m_pushed { false };
 };
 
+inline void RenderLayoutState::resetLineClamp()
+{
+    m_maximumLineCountForLineClamp = { };
+    m_visibleLineCountForLineClamp = { };
+}
+
 } // namespace WebCore