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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkBBoxHierarchy_DEFINED
#define SkBBoxHierarchy_DEFINED
#include "SkRect.h"
#include "SkTDArray.h"
#include "SkRefCnt.h"
/**
* Interface for a client class that implements utility methods needed
* by SkBBoxHierarchy that require intrinsic knowledge of the data
* object type that is stored in the bounding box hierarchy.
*/
class SkBBoxHierarchyClient {
public:
virtual ~SkBBoxHierarchyClient() {}
/**
* Implements a rewind stop condition used by rewindInserts
* Must returns true if 'data' points to an object that should be re-wound
* by rewinfInserts.
*/
virtual bool shouldRewind(void* data) = 0;
};
/**
* Interface for a spatial data structure that associates user data pointers with axis-aligned
* bounding boxes, and allows efficient retrieval of intersections with query rectangles.
*/
class SkBBoxHierarchy : public SkRefCnt {
public:
SK_DECLARE_INST_COUNT(SkBBoxHierarchy)
SkBBoxHierarchy() : fClient(NULL) {}
/**
* Insert a data pointer and corresponding bounding box
* @param data The data pointer, may be NULL
* @param bounds The bounding box, should not be empty
* @param defer Whether or not it is acceptable to delay insertion of this element (building up
* an entire spatial data structure at once is often faster and produces better
* structures than repeated inserts) until flushDeferredInserts is called or the first
* search.
*/
virtual void insert(void* data, const SkIRect& bounds, bool defer = false) = 0;
/**
* If any insertions have been deferred, this forces them to be inserted
*/
virtual void flushDeferredInserts() = 0;
/**
* Populate 'results' with data pointers corresponding to bounding boxes that intersect 'query'
*/
virtual void search(const SkIRect& query, SkTDArray<void*>* results) = 0;
virtual void clear() = 0;
/**
* Gets the number of insertions actually made (does not include deferred insertions)
*/
virtual int getCount() const = 0;
/**
* Returns the depth of the currently allocated tree. The root node counts for 1 level,
* so it should be 1 or more if there's a root node. This information provides details
* about the underlying structure, which is useful mainly for testing purposes.
*
* Returns 0 if there are currently no nodes in the tree.
* Returns -1 if the structure isn't a tree.
*/
virtual int getDepth() const = 0;
/**
* Rewinds all the most recently inserted data elements until an element
* is encountered for which client->shouldRewind(data) returns false. May
* not rewind elements that were inserted prior to the last call to
* flushDeferredInserts.
*/
virtual void rewindInserts() = 0;
void setClient(SkBBoxHierarchyClient* client) { fClient = client; }
protected:
SkBBoxHierarchyClient* fClient;
private:
typedef SkRefCnt INHERITED;
};
#endif
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