Creates all the raw offset curves for a buffer of a Geometry. More...

#include <OffsetCurveSetBuilder.h>

Collaboration diagram for geos::operation::buffer::OffsetCurveSetBuilder:

Public Member Functions
	OffsetCurveSetBuilder (const geom::Geometry &newInputGeom, double newDistance, OffsetCurveBuilder &newCurveBuilder)
	Constructor. More...

	~OffsetCurveSetBuilder ()
	Destructor. More...

std::vector< noding::SegmentString * > &	getCurves ()
	Computes the set of raw offset curves for the buffer. More...

void	addCurves (const std::vector< geom::CoordinateSequence * > &lineList, geom::Location leftLoc, geom::Location rightLoc)
	Add raw curves for a set of CoordinateSequences. More...

Private Member Functions
void	addCurve (geom::CoordinateSequence *coord, geom::Location leftLoc, geom::Location rightLoc)

void	add (const geom::Geometry &g)

void	addCollection (const geom::GeometryCollection *gc)

void	addPoint (const geom::Point *p)

void	addLineString (const geom::LineString *line)

void	addPolygon (const geom::Polygon *p)

void	addRingBothSides (const geom::CoordinateSequence *coord, double p_distance)

void	addRingSide (const geom::CoordinateSequence *coord, double offsetDistance, int side, geom::Location cwLeftLoc, geom::Location cwRightLoc)

bool	isErodedCompletely (const geom::LinearRing *ringCoord, double bufferDistance)

bool	isTriangleErodedCompletely (const geom::CoordinateSequence *triCoords, double bufferDistance)

	OffsetCurveSetBuilder (const OffsetCurveSetBuilder &other)=delete

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

Private Attributes
std::vector< geomgraph::Label * >	newLabels

const geom::Geometry &	inputGeom

double	distance

OffsetCurveBuilder &	curveBuilder

std::vector< noding::SegmentString * >	curveList

Detailed Description

Creates all the raw offset curves for a buffer of a Geometry.

Raw curves need to be noded together and polygonized to form the final buffer area.

Definition at line 71 of file OffsetCurveSetBuilder.h.

Constructor & Destructor Documentation

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

privatedelete

geos::operation::buffer::OffsetCurveSetBuilder::OffsetCurveSetBuilder	(	const geom::Geometry &	newInputGeom,
		double	newDistance,
		OffsetCurveBuilder &	newCurveBuilder
	)

Constructor.

geos::operation::buffer::OffsetCurveSetBuilder::~OffsetCurveSetBuilder ( )

Destructor.

Member Function Documentation

void geos::operation::buffer::OffsetCurveSetBuilder::add ( const geom::Geometry & g )

private

void geos::operation::buffer::OffsetCurveSetBuilder::addCollection ( const geom::GeometryCollection * gc )

private

void geos::operation::buffer::OffsetCurveSetBuilder::addCurve	(	geom::CoordinateSequence *	coord,
		geom::Location	leftLoc,
		geom::Location	rightLoc
	)

private

Creates a noding::SegmentString for a coordinate list which is a raw offset curve, and adds it to the list of buffer curves. The noding::SegmentString is tagged with a geomgraph::Label giving the topology of the curve. The curve may be oriented in either direction. If the curve is oriented CW, the locations will be:

Left: Location.EXTERIOR
Right: Location.INTERIOR

Parameters

coord is raw offset curve, ownership transferred here

void geos::operation::buffer::OffsetCurveSetBuilder::addCurves	(	const std::vector< geom::CoordinateSequence * > &	lineList,
		geom::Location	leftLoc,
		geom::Location	rightLoc
	)

Add raw curves for a set of CoordinateSequences.

Parameters

lineList	is a list of CoordinateSequence, ownership of which is transferred here
leftLoc	left location
rightLoc	right location

void geos::operation::buffer::OffsetCurveSetBuilder::addLineString ( const geom::LineString * line )

private

void geos::operation::buffer::OffsetCurveSetBuilder::addPoint ( const geom::Point * p )

private

Add a Point to the graph.

void geos::operation::buffer::OffsetCurveSetBuilder::addPolygon ( const geom::Polygon * p )

private

void geos::operation::buffer::OffsetCurveSetBuilder::addRingBothSides	(	const geom::CoordinateSequence *	coord,
		double	p_distance
	)

private

void geos::operation::buffer::OffsetCurveSetBuilder::addRingSide	(	const geom::CoordinateSequence *	coord,
		double	offsetDistance,
		int	side,
		geom::Location	cwLeftLoc,
		geom::Location	cwRightLoc
	)

private

Add an offset curve for a polygon ring. The side and left and right topological location arguments assume that the ring is oriented CW. If the ring is in the opposite orientation, the left and right locations must be interchanged and the side flipped.

Parameters

coord	the coordinates of the ring (must not contain repeated points)
offsetDistance	the distance at which to create the buffer
side	the side of the ring on which to construct the buffer line
cwLeftLoc	the location on the L side of the ring (if it is CW)
cwRightLoc	the location on the R side of the ring (if it is CW)

std::vector<noding::SegmentString*>& geos::operation::buffer::OffsetCurveSetBuilder::getCurves ( )

Computes the set of raw offset curves for the buffer.

Each offset curve has an attached geomgraph::Label indicating its left and right location.

Returns: a Collection of SegmentStrings representing the raw buffer curves

bool geos::operation::buffer::OffsetCurveSetBuilder::isErodedCompletely	(	const geom::LinearRing *	ringCoord,
		double	bufferDistance
	)

private

The ringCoord is assumed to contain no repeated points. It may be degenerate (i.e. contain only 1, 2, or 3 points). In this case it has no area, and hence has a minimum diameter of 0.

Parameters

ringCoord
bufferDistance

Returns

bool geos::operation::buffer::OffsetCurveSetBuilder::isTriangleErodedCompletely	(	const geom::CoordinateSequence *	triCoords,
		double	bufferDistance
	)

private

Tests whether a triangular ring would be eroded completely by the given buffer distance. This is a precise test. It uses the fact that the inner buffer of a triangle converges on the inCentre of the triangle (the point equidistant from all sides). If the buffer distance is greater than the distance of the inCentre from a side, the triangle will be eroded completely.

This test is important, since it removes a problematic case where the buffer distance is slightly larger than the inCentre distance. In this case the triangle buffer curve "inverts" with incorrect topology, producing an incorrect hole in the buffer.

Parameters

triCoord
bufferDistance

Returns

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

privatedelete

Member Data Documentation

OffsetCurveBuilder& geos::operation::buffer::OffsetCurveSetBuilder::curveBuilder

private

Definition at line 83 of file OffsetCurveSetBuilder.h.

std::vector<noding::SegmentString*> geos::operation::buffer::OffsetCurveSetBuilder::curveList

private

The raw offset curves computed. This class holds ownership of std::vector elements.

Definition at line 88 of file OffsetCurveSetBuilder.h.

double geos::operation::buffer::OffsetCurveSetBuilder::distance

private

Definition at line 81 of file OffsetCurveSetBuilder.h.

const geom::Geometry& geos::operation::buffer::OffsetCurveSetBuilder::inputGeom

private

Definition at line 79 of file OffsetCurveSetBuilder.h.

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

private

Definition at line 77 of file OffsetCurveSetBuilder.h.

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

OffsetCurveSetBuilder.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation