1 /* 2 * Copyright (C) 2012 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 17 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 21 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #ifndef TextAutosizer_h 27 #define TextAutosizer_h 28 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" 35 36 namespace WebCore { 37 38 class Document; 39 class RenderBlock; 40 class RenderObject; 41 struct TextAutosizingWindowInfo; 42 43 // Represents cluster related data. Instances should not persist between calls to processSubtree. 44 struct TextAutosizingClusterInfo { 45 explicit TextAutosizingClusterInfo(RenderBlock* root) 46 : root(root) 47 , blockContainingAllText(0) 48 , maxAllowedDifferenceFromTextWidth(150) 49 { 50 } 51 52 RenderBlock* root; 53 const RenderBlock* blockContainingAllText; 54 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; 58 59 // Descendants of the cluster that are narrower than the block containing all text and must be 60 // processed together. 61 Vector<TextAutosizingClusterInfo> narrowDescendants; 62 }; 63 64 class TextAutosizer FINAL { 65 WTF_MAKE_NONCOPYABLE(TextAutosizer); 66 67 public: 68 static PassOwnPtr<TextAutosizer> create(Document* document) { return adoptPtr(new TextAutosizer(document)); } 69 70 bool processSubtree(RenderObject* layoutRoot); 71 void recalculateMultipliers(); 72 73 static float computeAutosizedFontSize(float specifiedSize, float multiplier); 74 75 private: 76 friend class FastTextAutosizer; 77 78 enum TraversalDirection { 79 FirstToLast, 80 LastToFirst 81 }; 82 83 explicit TextAutosizer(Document*); 84 85 bool isApplicable() const; 86 float clusterMultiplier(WritingMode, const TextAutosizingWindowInfo&, float textWidth) const; 87 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&); 92 93 void setMultiplier(RenderObject*, float); 94 void setMultiplierForList(RenderObject* renderer, float multiplier); 95 96 unsigned getCachedHash(const RenderObject* renderer, bool putInCacheIfAbsent); 97 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); 103 104 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); 112 113 // 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); 115 116 static const RenderBlock* findDeepestBlockContainingAllText(const RenderBlock* cluster); 117 118 // 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); 121 122 // 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> >&); 126 127 void addNonAutosizedCluster(unsigned key, TextAutosizingClusterInfo& value); 128 void secondPassProcessStaleNonAutosizedClusters(); 129 void processStaleContainer(float multiplier, RenderBlock* cluster, TextAutosizingClusterInfo&); 130 131 Document* m_document; 132 133 HashMap<const RenderObject*, unsigned> m_hashCache; 134 135 // 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; 138 139 // Mapping from a cluster hash to the corresponding cluster infos which have not been autosized yet. 140 HashMap<unsigned, OwnPtr<Vector<TextAutosizingClusterInfo> > > m_nonAutosizedClusters; 141 142 bool m_previouslyAutosized; 143 }; 144 145 } // namespace WebCore 146 147 #endif // TextAutosizer_h 148