Computes the raw offset curve for a single Geometry component (ring, line or point). More...

#include <OffsetCurveBuilder.h>

Collaboration diagram for geos::operation::buffer::OffsetCurveBuilder:

Public Member Functions
	OffsetCurveBuilder (const geom::PrecisionModel *newPrecisionModel, const BufferParameters &nBufParams)

const BufferParameters &	getBufferParameters () const
	Gets the buffer parameters being used to generate the curve. More...

bool	isLineOffsetEmpty (double distance)

void	getLineCurve (const geom::CoordinateSequence inputPts, double distance, std::vector< geom::CoordinateSequence > &lineList)
	This method handles single points as well as lines. More...

void	getSingleSidedLineCurve (const geom::CoordinateSequence inputPts, double distance, std::vector< geom::CoordinateSequence > &lineList, bool leftSide, bool rightSide)
	This method handles single points as well as lines. More...

void	getRingCurve (const geom::CoordinateSequence inputPts, int side, double distance, std::vector< geom::CoordinateSequence > &lineList)
	This method handles the degenerate cases of single points and lines, as well as rings. More...

Private Member Functions
double	simplifyTolerance (double bufDistance)
	Computes the distance tolerance to use during input line simplification. More...

void	computeLineBufferCurve (const geom::CoordinateSequence &inputPts, OffsetSegmentGenerator &segGen)

void	computeSingleSidedBufferCurve (const geom::CoordinateSequence &inputPts, bool isRightSide, OffsetSegmentGenerator &segGen)

void	computeRingBufferCurve (const geom::CoordinateSequence &inputPts, int side, OffsetSegmentGenerator &segGen)

std::unique_ptr< OffsetSegmentGenerator >	getSegGen (double dist)

void	computePointCurve (const geom::Coordinate &pt, OffsetSegmentGenerator &segGen)

	OffsetCurveBuilder (const OffsetCurveBuilder &other)=delete

OffsetCurveBuilder &	operator= (const OffsetCurveBuilder &rhs)=delete

Private Attributes
double	distance

const geom::PrecisionModel *	precisionModel

const BufferParameters &	bufParams

Static Private Attributes
static const double	SIMPLIFY_FACTOR
	Use a value which results in a potential distance error which is significantly less than the error due to the quadrant segment discretization. More...

Detailed Description

Computes the raw offset curve for a single Geometry component (ring, line or point).

A raw offset curve line is not noded - it may contain self-intersections (and usually will). The final buffer polygon is computed by forming a topological graph of all the noded raw curves and tracing outside contours. The points in the raw curve are rounded to a given geom::PrecisionModel.

Definition at line 62 of file OffsetCurveBuilder.h.

Constructor & Destructor Documentation

geos::operation::buffer::OffsetCurveBuilder::OffsetCurveBuilder	(	const geom::PrecisionModel *	newPrecisionModel,
		const BufferParameters &	nBufParams
	)

inline

Definition at line 72 of file OffsetCurveBuilder.h.

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

privatedelete

Member Function Documentation

void geos::operation::buffer::OffsetCurveBuilder::computeLineBufferCurve	(	const geom::CoordinateSequence &	inputPts,
		OffsetSegmentGenerator &	segGen
	)

private

void geos::operation::buffer::OffsetCurveBuilder::computePointCurve	(	const geom::Coordinate &	pt,
		OffsetSegmentGenerator &	segGen
	)

private

void geos::operation::buffer::OffsetCurveBuilder::computeRingBufferCurve	(	const geom::CoordinateSequence &	inputPts,
		int	side,
		OffsetSegmentGenerator &	segGen
	)

private

void geos::operation::buffer::OffsetCurveBuilder::computeSingleSidedBufferCurve	(	const geom::CoordinateSequence &	inputPts,
		bool	isRightSide,
		OffsetSegmentGenerator &	segGen
	)

private

const BufferParameters& geos::operation::buffer::OffsetCurveBuilder::getBufferParameters ( ) const

inline

Gets the buffer parameters being used to generate the curve.

Returns: the buffer parameters being used

Definition at line 86 of file OffsetCurveBuilder.h.

void geos::operation::buffer::OffsetCurveBuilder::getLineCurve	(	const geom::CoordinateSequence *	inputPts,
		double	distance,
		std::vector< geom::CoordinateSequence * > &	lineList
	)

This method handles single points as well as lines.

Lines are assumed to not be closed (the function will not fail for closed lines, but will generate superfluous line caps).

Parameters

inputPts	input points
distance	offset distance
lineList	the std::vector to which the newly created CoordinateSequences will be pushed_back. Caller is responsible to delete these new elements.

void geos::operation::buffer::OffsetCurveBuilder::getRingCurve	(	const geom::CoordinateSequence *	inputPts,
		int	side,
		double	distance,
		std::vector< geom::CoordinateSequence * > &	lineList
	)

This method handles the degenerate cases of single points and lines, as well as rings.

Parameters

inputPts	input points
side	a Position
distance	offset distance
lineList	the std::vector to which CoordinateSequences will be pushed_back

std::unique_ptr<OffsetSegmentGenerator> geos::operation::buffer::OffsetCurveBuilder::getSegGen ( double dist )

private

void geos::operation::buffer::OffsetCurveBuilder::getSingleSidedLineCurve	(	const geom::CoordinateSequence *	inputPts,
		double	distance,
		std::vector< geom::CoordinateSequence * > &	lineList,
		bool	leftSide,
		bool	rightSide
	)

This method handles single points as well as lines.

Lines are assumed to not be closed (the function will not fail for closed lines, but will generate superfluous line caps).

Parameters

inputPts	input points
distance	offset distance
lineList	the std::vector to which newly created CoordinateSequences will be pushed_back. Caller will be responsible to delete them.
leftSide	indicates that the left side buffer will be obtained/skipped
rightSide	indicates that the right side buffer will be obtained/skipped

Note: This is a GEOS extension.

bool geos::operation::buffer::OffsetCurveBuilder::isLineOffsetEmpty ( double distance )

Tests whether the offset curve for line or point geometries at the given offset distance is empty (does not exist). This is the case if:

the distance is zero,
the distance is negative, except for the case of singled-sided buffers

Parameters

distance the offset curve distance

Returns: true if the offset curve is empty

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

privatedelete

double geos::operation::buffer::OffsetCurveBuilder::simplifyTolerance ( double bufDistance )

private

Computes the distance tolerance to use during input line simplification.

Parameters

bufDistance the buffer distance

Returns: the simplification tolerance

Member Data Documentation

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

private

Definition at line 163 of file OffsetCurveBuilder.h.

double geos::operation::buffer::OffsetCurveBuilder::distance

private

Definition at line 159 of file OffsetCurveBuilder.h.

const geom::PrecisionModel* geos::operation::buffer::OffsetCurveBuilder::precisionModel

private

Definition at line 161 of file OffsetCurveBuilder.h.

const double geos::operation::buffer::OffsetCurveBuilder::SIMPLIFY_FACTOR

staticprivate

Use a value which results in a potential distance error which is significantly less than the error due to the quadrant segment discretization.

For QS = 8 a value of 100 is reasonable. This should produce a maximum of 1% distance error.

Definition at line 172 of file OffsetCurveBuilder.h.

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

OffsetCurveBuilder.h

Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation