1 /* 2 * Copyright 2014 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkQuadTree_DEFINED 9 #define SkQuadTree_DEFINED 10 11 #include "SkRect.h" 12 #include "SkTDArray.h" 13 #include "SkBBoxHierarchy.h" 14 #include "SkTInternalSList.h" 15 #include "SkTObjectPool.h" 16 17 /** 18 * A QuadTree implementation. In short, it is a tree containing a hierarchy of bounding rectangles 19 * in which each internal node has exactly four children. 20 * 21 * For more details see: 22 * 23 * http://en.wikipedia.org/wiki/Quadtree 24 */ 25 class SkQuadTree : public SkBBoxHierarchy { 26 public: 27 SK_DECLARE_INST_COUNT(SkQuadTree) 28 29 /** 30 * Quad tree constructor. 31 * @param bounds The bounding box for the root of the quad tree. 32 * giving the quad tree bounds that fall outside the root 33 * bounds may result in pathological but correct behavior. 34 */ 35 SkQuadTree(const SkIRect& bounds); 36 37 virtual ~SkQuadTree(); 38 39 /** 40 * Insert a node, consisting of bounds and a data value into the tree, if we don't immediately 41 * need to use the tree; we may allow the insert to be deferred (this can allow us to bulk-load 42 * a large batch of nodes at once, which tends to be faster and produce a better tree). 43 * @param data The data value 44 * @param bounds The corresponding bounding box 45 * @param defer Can this insert be deferred? (this may be ignored) 46 */ 47 virtual void insert(void* data, const SkIRect& bounds, bool defer = false) SK_OVERRIDE; 48 49 /** 50 * If any inserts have been deferred, this will add them into the tree 51 */ 52 virtual void flushDeferredInserts() SK_OVERRIDE; 53 54 /** 55 * Given a query rectangle, populates the passed-in array with the elements it intersects 56 */ 57 virtual void search(const SkIRect& query, SkTDArray<void*>* results) SK_OVERRIDE; 58 59 virtual void clear() SK_OVERRIDE; 60 61 /** 62 * Gets the depth of the tree structure 63 */ 64 virtual int getDepth() const SK_OVERRIDE; 65 66 /** 67 * This gets the insertion count (rather than the node count) 68 */ getCount()69 virtual int getCount() const SK_OVERRIDE { 70 return fEntryPool.allocated() - fEntryPool.available(); 71 } 72 73 virtual void rewindInserts() SK_OVERRIDE; 74 75 private: 76 struct Entry { EntryEntry77 Entry() : fData(NULL) {} 78 SkIRect fBounds; 79 void* fData; 80 SK_DECLARE_INTERNAL_SLIST_INTERFACE(Entry); 81 }; 82 83 static const int kChildCount = 4; 84 85 struct Node { NodeNode86 Node() { 87 for (int index=0; index<kChildCount; ++index) { 88 fChildren[index] = NULL; 89 } 90 } 91 SkTInternalSList<Entry> fEntries; 92 SkIRect fBounds; 93 SkIPoint fSplitPoint; // Only valid if the node has children. 94 Node* fChildren[kChildCount]; 95 SK_DECLARE_INTERNAL_SLIST_ADAPTER(Node, fChildren[0]); 96 }; 97 98 SkTObjectPool<Entry> fEntryPool; 99 SkTObjectPool<Node> fNodePool; 100 Node* fRoot; 101 SkIRect fRootBounds; 102 SkTInternalSList<Entry> fDeferred; 103 104 void insert(Node* node, Entry* entry); 105 void split(Node* node); 106 void search(Node* node, const SkIRect& query, SkTDArray<void*>* results) const; 107 void clear(Node* node); 108 int getDepth(Node* node) const; 109 110 typedef SkBBoxHierarchy INHERITED; 111 }; 112 113 #endif 114