Merge 143318

Source/WebCore/rendering/TextAutosizer.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 131 matching lines @@
         // Ignore box width in excess of the layout width, to avoid extreme multipliers.
         float logicalClusterWidth = std::min<float>(textWidth, logicalLayoutWidth);
 
         multiplier = logicalClusterWidth / logicalWindowWidth;
         multiplier *= m_document->settings()->textAutosizingFontScaleFactor();
         multiplier = std::max(1.0f, multiplier);
     }
 
     processContainer(multiplier, container, clusterInfo, subtreeRoot, windowInfo);
 
-    processCompositeCluster(clusterInfo.narrowDescendants, windowInfo);
+    Vector<Vector<TextAutosizingClusterInfo> > narrowDescendantsGroups;
+    getNarrowDescendantsGroupedByWidth(clusterInfo, narrowDescendantsGroups);
+    for (size_t i = 0; i < narrowDescendantsGroups.size(); ++i)
+        processCompositeCluster(narrowDescendantsGroups[i], windowInfo);
 }
 
 void TextAutosizer::processCluster(TextAutosizingClusterInfo& clusterInfo, RenderBlock* container, RenderObject* subtreeRoot, const TextAutosizingWindowInfo& windowInfo)
 {
     // Many pages set a max-width on their content. So especially for the RenderView, instead of
     // just taking the width of |cluster| we find the lowest common ancestor of the first and last
     // descendant text node of the cluster (i.e. the deepest wrapper block that contains all the
     // text), and use its width instead.
     clusterInfo.blockContainingAllText = findDeepestBlockContainingAllText(clusterInfo.root);
     float textWidth = clusterInfo.blockContainingAllText->contentLogicalWidth();
@@ skipping 386 matching lines @@
             if (leaf)
                 return leaf;
         }
         child = (direction == FirstToLast) ? child->nextSibling() : child->previousSibling();
     }
     --depth;
 
     return 0;
 }
 
+namespace {
+
+// Compares the width of the specified cluster's roots in descending order.
+bool clusterWiderThanComparisonFn(const TextAutosizingClusterInfo& first, const TextAutosizingClusterInfo& second)
+{
+    return first.root->contentLogicalWidth() > second.root->contentLogicalWidth();
+}
+
+} // namespace
+
+void TextAutosizer::getNarrowDescendantsGroupedByWidth(const TextAutosizingClusterInfo& parentClusterInfo, Vector<Vector<TextAutosizingClusterInfo> >& groups)
+{
+    ASSERT(parentClusterInfo.blockContainingAllText);
+    ASSERT(groups.isEmpty());
+
+    Vector<TextAutosizingClusterInfo> clusterInfos(parentClusterInfo.narrowDescendants);
+    if (clusterInfos.isEmpty())
+        return;
+
+    std::sort(clusterInfos.begin(), clusterInfos.end(), &clusterWiderThanComparisonFn);
+    groups.grow(1);
+
+    // If the width difference between two consecutive elements of |clusterInfos| is greater than
+    // this empirically determined value, the next element should start a new group.
+    const float maxWidthDifferenceWithinGroup = 100;
+    for (size_t i = 0; i < clusterInfos.size(); ++i) {
+        groups.last().append(clusterInfos[i]);
+
+        if (i + 1 < clusterInfos.size()) {
+            float currentWidth = clusterInfos[i].root->contentLogicalWidth();
+            float nextWidth = clusterInfos[i + 1].root->contentLogicalWidth();
+            if (currentWidth - nextWidth > maxWidthDifferenceWithinGroup)
+                groups.grow(groups.size() + 1);
+        }
+    }
+}
+
 } // namespace WebCore
 
 #endif // ENABLE(TEXT_AUTOSIZING)