michael@0: /*
michael@0:  * Copyright 2014 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef SkQuadTree_DEFINED
michael@0: #define SkQuadTree_DEFINED
michael@0: 
michael@0: #include "SkRect.h"
michael@0: #include "SkTDArray.h"
michael@0: #include "SkBBoxHierarchy.h"
michael@0: #include "SkTInternalSList.h"
michael@0: #include "SkTObjectPool.h"
michael@0: 
michael@0: /**
michael@0:  * A QuadTree implementation. In short, it is a tree containing a hierarchy of bounding rectangles
michael@0:  * in which each internal node has exactly four children.
michael@0:  *
michael@0:  * For more details see:
michael@0:  *
michael@0:  * http://en.wikipedia.org/wiki/Quadtree
michael@0:  */
michael@0: class SkQuadTree : public SkBBoxHierarchy {
michael@0: public:
michael@0:     SK_DECLARE_INST_COUNT(SkQuadTree)
michael@0: 
michael@0:     /**
michael@0:      * Quad tree constructor.
michael@0:      * @param bounds The bounding box for the root of the quad tree.
michael@0:      *               giving the quad tree bounds that fall outside the root
michael@0:      *               bounds may result in pathological but correct behavior.
michael@0:      */
michael@0:     SkQuadTree(const SkIRect& bounds);
michael@0: 
michael@0:     virtual ~SkQuadTree();
michael@0: 
michael@0:     /**
michael@0:      * Insert a node, consisting of bounds and a data value into the tree, if we don't immediately
michael@0:      * need to use the tree; we may allow the insert to be deferred (this can allow us to bulk-load
michael@0:      * a large batch of nodes at once, which tends to be faster and produce a better tree).
michael@0:      *  @param data The data value
michael@0:      *  @param bounds The corresponding bounding box
michael@0:      *  @param defer Can this insert be deferred? (this may be ignored)
michael@0:      */
michael@0:     virtual void insert(void* data, const SkIRect& bounds, bool defer = false) SK_OVERRIDE;
michael@0: 
michael@0:     /**
michael@0:      * If any inserts have been deferred, this will add them into the tree
michael@0:      */
michael@0:     virtual void flushDeferredInserts() SK_OVERRIDE;
michael@0: 
michael@0:     /**
michael@0:      * Given a query rectangle, populates the passed-in array with the elements it intersects
michael@0:      */
michael@0:     virtual void search(const SkIRect& query, SkTDArray<void*>* results) SK_OVERRIDE;
michael@0: 
michael@0:     virtual void clear() SK_OVERRIDE;
michael@0: 
michael@0:     /**
michael@0:      * Gets the depth of the tree structure
michael@0:      */
michael@0:     virtual int getDepth() const SK_OVERRIDE;
michael@0: 
michael@0:     /**
michael@0:      * This gets the insertion count (rather than the node count)
michael@0:      */
michael@0:     virtual int getCount() const SK_OVERRIDE { return fEntryCount; }
michael@0: 
michael@0:     virtual void rewindInserts() SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     struct Entry {
michael@0:         Entry() : fData(NULL) {}
michael@0:         SkIRect fBounds;
michael@0:         void* fData;
michael@0:         SK_DECLARE_INTERNAL_SLIST_INTERFACE(Entry);
michael@0:     };
michael@0: 
michael@0:     static const int kChildCount = 4;
michael@0: 
michael@0:     struct Node {
michael@0:         Node() {
michael@0:             for (int index=0; index<kChildCount; ++index) {
michael@0:                 fChildren[index] = NULL;
michael@0:             }
michael@0:         }
michael@0:         SkTInternalSList<Entry> fEntries;
michael@0:         SkIRect fBounds;
michael@0:         SkIPoint fSplitPoint; // Only valid if the node has children.
michael@0:         Node* fChildren[kChildCount];
michael@0:         SK_DECLARE_INTERNAL_SLIST_ADAPTER(Node, fChildren[0]);
michael@0:     };
michael@0: 
michael@0:     SkTObjectPool<Entry> fEntryPool;
michael@0:     SkTObjectPool<Node> fNodePool;
michael@0:     int fEntryCount;
michael@0:     Node* fRoot;
michael@0:     SkTInternalSList<Entry> fDeferred;
michael@0: 
michael@0:     Node* pickChild(Node* node, const SkIRect& bounds) const;
michael@0:     void insert(Node* node, Entry* entry);
michael@0:     void search(Node* node, const SkIRect& query, SkTDArray<void*>* results) const;
michael@0:     void clear(Node* node);
michael@0:     int getDepth(Node* node) const;
michael@0: 
michael@0:     typedef SkBBoxHierarchy INHERITED;
michael@0: };
michael@0: 
michael@0: #endif