geos::operation::buffer::BufferBuilder Class Reference

Builds the buffer geometry for a given input geometry and precision model. More...

#include <BufferBuilder.h>

Collaboration diagram for geos::operation::buffer::BufferBuilder:

Public Member Functions
	BufferBuilder (const BufferParameters &nBufParams)
	~BufferBuilder ()
void	setWorkingPrecisionModel (const geom::PrecisionModel *pm)
void	setNoder (noding::Noder *newNoder)
geom::Geometry *	buffer (const geom::Geometry *g, double distance)
geom::Geometry *	bufferLineSingleSided (const geom::Geometry *g, double distance, bool leftSide)

Private Member Functions
void	computeNodedEdges (std::vector< noding::SegmentString * > &bufSegStr, const geom::PrecisionModel *precisionModel)
void	insertUniqueEdge (geomgraph::Edge *e)
void	createSubgraphs (geomgraph::PlanarGraph *graph, std::vector< BufferSubgraph * > &list)
void	buildSubgraphs (const std::vector< BufferSubgraph * > &subgraphList, overlay::PolygonBuilder &polyBuilder)
noding::Noder *	getNoder (const geom::PrecisionModel *precisionModel)
	Return the externally-set noding::Noder OR a newly created one using the given precisionModel. More...
geom::Geometry *	createEmptyResultGeometry () const
	BufferBuilder (const BufferBuilder &other)=delete
BufferBuilder &	operator= (const BufferBuilder &rhs)=delete

Static Private Member Functions
static int	depthDelta (const geomgraph::Label &label)

Private Attributes
const BufferParameters &	bufParams
const geom::PrecisionModel *	workingPrecisionModel
algorithm::LineIntersector *	li
noding::IntersectionAdder *	intersectionAdder
noding::Noder *	workingNoder
const geom::GeometryFactory *	geomFact
geomgraph::EdgeList	edgeList
std::vector< geomgraph::Label * >	newLabels

Detailed Description

Builds the buffer geometry for a given input geometry and precision model.

Allows setting the level of approximation for circular arcs, and the precision model in which to carry out the computation.

When computing buffers in floating point double-precision it can happen that the process of iterated noding can fail to converge (terminate).

In this case a TopologyException will be thrown. Retrying the computation in a fixed precision can produce more robust results.

Definition at line 88 of file BufferBuilder.h.

Constructor & Destructor Documentation

geos::operation::buffer::BufferBuilder::BufferBuilder ( const BufferParameters &  nBufParams )

inline

Creates a new BufferBuilder

Parameters

nBufParams

buffer parameters, this object will keep a reference to the passed parameters so caller must make sure the object is kept alive for the whole lifetime of the buffer builder.

Definition at line 100 of file BufferBuilder.h.

geos::operation::buffer::BufferBuilder::~BufferBuilder

(

)

geos::operation::buffer::BufferBuilder::BufferBuilder ( const BufferBuilder &  other )

privatedelete

Member Function Documentation

geom::Geometry* geos::operation::buffer::BufferBuilder::buffer	(	const geom::Geometry *	g,
		double	distance
	)

geom::Geometry* geos::operation::buffer::BufferBuilder::bufferLineSingleSided	(	const geom::Geometry *	g,
		double	distance,
		bool	leftSide
	)

Generates offset curve for linear geometry.

Parameters

g	non-areal geometry object
distance	width of offset
leftSide	controls on which side of the input geometry offset curve is generated.

Note

For left-side offset curve, the offset will be at the left side of the input line and retain the same direction. For right-side offset curve, it'll be at the right side and in the opposite direction.

BufferParameters::setSingleSided parameter, which is specific to areal geometries only, is ignored by this routine.

Not in JTS: this is a GEOS extension

void geos::operation::buffer::BufferBuilder::buildSubgraphs ( const std::vector< BufferSubgraph * > &  subgraphList, overlay::PolygonBuilder &  polyBuilder  )

private

Completes the building of the input subgraphs by depth-labelling them, and adds them to the PolygonBuilder. The subgraph list must be sorted in rightmost-coordinate order.

Parameters

subgraphList	the subgraphs to build
polyBuilder	the PolygonBuilder which will build the final polygons

void geos::operation::buffer::BufferBuilder::computeNodedEdges ( std::vector< noding::SegmentString * > &  bufSegStr, const geom::PrecisionModel *  precisionModel  )

private

geom::Geometry* geos::operation::buffer::BufferBuilder::createEmptyResultGeometry ( ) const

private

Gets the standard result for an empty buffer. Since buffer always returns a polygonal result, this is chosen to be an empty polygon.

Returns

the empty result geometry, transferring ownership to caller.

void geos::operation::buffer::BufferBuilder::createSubgraphs ( geomgraph::PlanarGraph *  graph, std::vector< BufferSubgraph * > &  list  )

private

static int geos::operation::buffer::BufferBuilder::depthDelta ( const geomgraph::Label &  label )

staticprivate

Compute the change in depth as an edge is crossed from R to L

noding::Noder* geos::operation::buffer::BufferBuilder::getNoder ( const geom::PrecisionModel *  precisionModel )

private

Return the externally-set noding::Noder OR a newly created one using the given precisionModel.

NOTE: if an externally-set noding::Noder is available no check is performed to ensure it will use the given PrecisionModel

void geos::operation::buffer::BufferBuilder::insertUniqueEdge ( geomgraph::Edge *  e )

private

Inserted edges are checked to see if an identical edge already exists. If so, the edge is not inserted, but its label is merged with the existing edge.

The function takes responsability of releasing the Edge parameter memory when appropriate.

BufferBuilder& geos::operation::buffer::BufferBuilder::operator= ( const BufferBuilder &  rhs )

privatedelete

void geos::operation::buffer::BufferBuilder::setNoder ( noding::Noder *  newNoder )

inline

Sets the noding::Noder to use during noding. This allows choosing fast but non-robust noding, or slower but robust noding.

Parameters

newNoder

the noder to use

Definition at line 138 of file BufferBuilder.h.

void geos::operation::buffer::BufferBuilder::setWorkingPrecisionModel ( const geom::PrecisionModel *  pm )

inline

Sets the precision model to use during the curve computation and noding, if it is different to the precision model of the Geometry. If the precision model is less than the precision of the Geometry precision model, the Geometry must have previously been rounded to that precision.

Parameters

pm	the precision model to use

Definition at line 125 of file BufferBuilder.h.

Member Data Documentation

const BufferParameters& geos::operation::buffer::BufferBuilder::bufParams

private

Definition at line 175 of file BufferBuilder.h.

geomgraph::EdgeList geos::operation::buffer::BufferBuilder::edgeList

private

Definition at line 187 of file BufferBuilder.h.

const geom::GeometryFactory* geos::operation::buffer::BufferBuilder::geomFact

private

Definition at line 185 of file BufferBuilder.h.

noding::IntersectionAdder* geos::operation::buffer::BufferBuilder::intersectionAdder

private

Definition at line 181 of file BufferBuilder.h.

algorithm::LineIntersector* geos::operation::buffer::BufferBuilder::li

private

Definition at line 179 of file BufferBuilder.h.

std::vector<geomgraph::Label*> geos::operation::buffer::BufferBuilder::newLabels

private

Definition at line 189 of file BufferBuilder.h.

noding::Noder* geos::operation::buffer::BufferBuilder::workingNoder

private

Definition at line 183 of file BufferBuilder.h.

const geom::PrecisionModel* geos::operation::buffer::BufferBuilder::workingPrecisionModel

private

Definition at line 177 of file BufferBuilder.h.

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The documentation for this class was generated from the following file:

• BufferBuilder.h