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26 #ifndef TextAutosizer_h
27 #define TextAutosizer_h
29 #include "core/HTMLNames.h"
30 #include "platform/text/WritingMode.h"
31 #include "wtf/HashMap.h"
32 #include "wtf/Noncopyable.h"
33 #include "wtf/OwnPtr.h"
34 #include "wtf/PassOwnPtr.h"
41 struct TextAutosizingWindowInfo;
43 // Represents cluster related data. Instances should not persist between calls to processSubtree.
44 struct TextAutosizingClusterInfo {
45 explicit TextAutosizingClusterInfo(RenderBlock* root)
47 , blockContainingAllText(0)
48 , maxAllowedDifferenceFromTextWidth(150)
53 const RenderBlock* blockContainingAllText;
55 // Upper limit on the difference between the width of the cluster's block containing all
56 // text and that of a narrow child before the child becomes a separate cluster.
57 float maxAllowedDifferenceFromTextWidth;
59 // Descendants of the cluster that are narrower than the block containing all text and must be
60 // processed together.
61 Vector<TextAutosizingClusterInfo> narrowDescendants;
64 class TextAutosizer FINAL {
65 WTF_MAKE_NONCOPYABLE(TextAutosizer);
68 static PassOwnPtr<TextAutosizer> create(Document* document) { return adoptPtr(new TextAutosizer(document)); }
70 bool processSubtree(RenderObject* layoutRoot);
71 void recalculateMultipliers();
73 static float computeAutosizedFontSize(float specifiedSize, float multiplier);
76 friend class FastTextAutosizer;
78 enum TraversalDirection {
83 explicit TextAutosizer(Document*);
85 bool isApplicable() const;
86 float clusterMultiplier(WritingMode, const TextAutosizingWindowInfo&, float textWidth) const;
88 void processClusterInternal(TextAutosizingClusterInfo&, RenderBlock* container, RenderObject* subtreeRoot, const TextAutosizingWindowInfo&, float multiplier);
89 void processCluster(TextAutosizingClusterInfo&, RenderBlock* container, RenderObject* subtreeRoot, const TextAutosizingWindowInfo&);
90 void processCompositeCluster(Vector<TextAutosizingClusterInfo>&, const TextAutosizingWindowInfo&);
91 void processContainer(float multiplier, RenderBlock* container, TextAutosizingClusterInfo&, RenderObject* subtreeRoot, const TextAutosizingWindowInfo&);
93 void setMultiplier(RenderObject*, float);
94 void setMultiplierForList(RenderObject* renderer, float multiplier);
96 unsigned getCachedHash(const RenderObject* renderer, bool putInCacheIfAbsent);
98 static bool isAutosizingContainer(const RenderObject*);
99 static bool isNarrowDescendant(const RenderBlock*, TextAutosizingClusterInfo& parentClusterInfo);
100 static bool isWiderDescendant(const RenderBlock*, const TextAutosizingClusterInfo& parentClusterInfo);
101 static bool isIndependentDescendant(const RenderBlock*);
102 static bool isAutosizingCluster(const RenderBlock*, TextAutosizingClusterInfo& parentClusterInfo);
104 static bool containerShouldBeAutosized(const RenderBlock* container);
105 static bool containerContainsOneOfTags(const RenderBlock* cluster, const Vector<QualifiedName>& tags);
106 static bool containerIsRowOfLinks(const RenderObject* container);
107 static bool contentHeightIsConstrained(const RenderBlock* container);
108 static bool compositeClusterShouldBeAutosized(Vector<TextAutosizingClusterInfo>&, float blockWidth);
109 static void measureDescendantTextWidth(const RenderBlock* container, TextAutosizingClusterInfo&, float minTextWidth, float& textWidth);
110 unsigned computeCompositeClusterHash(Vector<TextAutosizingClusterInfo>&);
111 float computeMultiplier(Vector<TextAutosizingClusterInfo>&, const TextAutosizingWindowInfo&, float textWidth);
113 // Use to traverse the tree of descendants, excluding descendants of containers (but returning the containers themselves).
114 static RenderObject* nextInPreOrderSkippingDescendantsOfContainers(const RenderObject*, const RenderObject* stayWithin);
116 static const RenderBlock* findDeepestBlockContainingAllText(const RenderBlock* cluster);
118 // Depending on the traversal direction specified, finds the first or the last leaf text node child that doesn't
119 // belong to any cluster.
120 static const RenderObject* findFirstTextLeafNotInCluster(const RenderObject*, size_t& depth, TraversalDirection);
122 // Returns groups of narrow descendants of a given autosizing cluster. The groups are combined
123 // by the difference between the width of the descendant and the width of the parent cluster's
124 // |blockContainingAllText|.
125 static void getNarrowDescendantsGroupedByWidth(const TextAutosizingClusterInfo& parentClusterInfo, Vector<Vector<TextAutosizingClusterInfo> >&);
127 void addNonAutosizedCluster(unsigned key, TextAutosizingClusterInfo& value);
128 void secondPassProcessStaleNonAutosizedClusters();
129 void processStaleContainer(float multiplier, RenderBlock* cluster, TextAutosizingClusterInfo&);
131 Document* m_document;
133 HashMap<const RenderObject*, unsigned> m_hashCache;
135 // Mapping from all autosized (i.e. multiplier > 1) cluster hashes to their respective multipliers.
136 HashMap<unsigned, float> m_hashToMultiplier;
137 Vector<unsigned> m_hashesToAutosizeSecondPass;
139 // Mapping from a cluster hash to the corresponding cluster infos which have not been autosized yet.
140 HashMap<unsigned, OwnPtr<Vector<TextAutosizingClusterInfo> > > m_nonAutosizedClusters;
142 bool m_previouslyAutosized;
145 } // namespace WebCore
147 #endif // TextAutosizer_h