OGR
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#include "cpl_port.h"
Go to the source code of this file.
Classes | |
struct | CPLRectObj |
Functions | |
CPLQuadTree * | CPLQuadTreeCreate (const CPLRectObj *pGlobalBounds, CPLQuadTreeGetBoundsFunc pfnGetBounds) |
void | CPLQuadTreeDestroy (CPLQuadTree *hQuadtree) |
void | CPLQuadTreeSetBucketCapacity (CPLQuadTree *hQuadtree, int nBucketCapacity) |
int | CPLQuadTreeGetAdvisedMaxDepth (int nExpectedFeatures) |
void | CPLQuadTreeSetMaxDepth (CPLQuadTree *hQuadtree, int nMaxDepth) |
void | CPLQuadTreeInsert (CPLQuadTree *hQuadtree, void *hFeature) |
void | CPLQuadTreeInsertWithBounds (CPLQuadTree *hQuadtree, void *hFeature, const CPLRectObj *psBounds) |
void ** | CPLQuadTreeSearch (const CPLQuadTree *hQuadtree, const CPLRectObj *pAoi, int *pnFeatureCount) |
void | CPLQuadTreeForeach (const CPLQuadTree *hQuadtree, CPLQuadTreeForeachFunc pfnForeach, void *pUserData) |
Quad tree implementation.
A quadtree is a tree data structure in which each internal node has up to four children. Quadtrees are most often used to partition a two dimensional space by recursively subdividing it into four quadrants or regions
CPLQuadTree* CPLQuadTreeCreate | ( | const CPLRectObj * | pGlobalBounds, |
CPLQuadTreeGetBoundsFunc | pfnGetBounds | ||
) |
Create a new quadtree
pGlobalBounds | a pointer to the global extent of all the elements that will be inserted |
pfnGetBounds | a user provided function to get the bounding box of the inserted elements. If it is set to NULL, then CPLQuadTreeInsertWithBounds() must be used, and extra memory will be used to keep features bounds in the quad tree. |
References CPLMalloc().
void CPLQuadTreeDestroy | ( | CPLQuadTree * | hQuadTree | ) |
Destroy a quadtree
hQuadTree | the quad tree to destroy |
References CPLMalloc(), and CPLRealloc().
void CPLQuadTreeForeach | ( | const CPLQuadTree * | hQuadTree, |
CPLQuadTreeForeachFunc | pfnForeach, | ||
void * | pUserData | ||
) |
Walk through the quadtree and runs the provided function on all the elements
This function is provided with the user_data argument of pfnForeach. It must return TRUE to go on the walk through the hash set, or FALSE to make it stop.
Note : the structure of the quadtree must NOT be modified during the walk.
hQuadTree | the quad tree |
pfnForeach | the function called on each element. |
pUserData | the user data provided to the function. |
int CPLQuadTreeGetAdvisedMaxDepth | ( | int | nExpectedFeatures | ) |
Returns the optimal depth of a quadtree to hold nExpectedFeatures
nExpectedFeatures | the expected maximum number of elements to be inserted |
References CPLDebug().
void CPLQuadTreeInsert | ( | CPLQuadTree * | hQuadTree, |
void * | hFeature | ||
) |
Insert a feature into a quadtree
hQuadTree | the quad tree |
hFeature | the feature to insert |
References CPLError().
void CPLQuadTreeInsertWithBounds | ( | CPLQuadTree * | hQuadTree, |
void * | hFeature, | ||
const CPLRectObj * | psBounds | ||
) |
Insert a feature into a quadtree
hQuadTree | the quad tree |
hFeature | the feature to insert |
psBounds | bounds of the feature |
void** CPLQuadTreeSearch | ( | const CPLQuadTree * | hQuadTree, |
const CPLRectObj * | pAoi, | ||
int * | pnFeatureCount | ||
) |
Returns all the elements inserted whose bounding box intersects the provided area of interest
hQuadTree | the quad tree |
pAoi | the pointer to the area of interest |
pnFeatureCount | the user data provided to the function. |
void CPLQuadTreeSetBucketCapacity | ( | CPLQuadTree * | hQuadTree, |
int | nBucketCapacity | ||
) |
Set the maximum capacity of a node of a quadtree. The default value is 8. Note that the maximum capacity will only be honoured if the features inserted have a point geometry. Otherwise it may be exceeded.
hQuadTree | the quad tree |
nBucketCapacity | the maximum capactiy of a node of a quadtree |
void CPLQuadTreeSetMaxDepth | ( | CPLQuadTree * | hQuadTree, |
int | nMaxDepth | ||
) |
Set the maximum depth of a quadtree. By default, quad trees have no maximum depth, but a maximum bucket capacity.
hQuadTree | the quad tree |
nMaxDepth | the maximum depth allowed |