/**********************************************************************
*
* GEOS - Geometry Engine Open Source
* http://geos.osgeo.org
*
* Copyright (C) 2009-2011 Sandro Santilli <strk@kbt.io>
* Copyright (C) 2006-2007 Refractions Research Inc.
*
* This is free software; you can redistribute and/or modify it under
* the terms of the GNU Lesser General Public Licence as published
* by the Free Software Foundation.
* See the COPYING file for more information.
*
**********************************************************************
*
* Last port: operation/buffer/OffsetCurveBuilder.java r378 (JTS-1.12)
*
**********************************************************************/
#pragma once
#include <geos/export.h>
#include <geos/operation/buffer/BufferParameters.h> // for composition
#include <geos/operation/buffer/OffsetSegmentGenerator.h>
#include <vector>
#include <memory> // for unique_ptr
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4251) // warning C4251: needs to have dll-interface to be used by clients of class
#endif
// Forward declarations
namespace geos {
namespace geom {
class CoordinateSequence;
class PrecisionModel;
}
}
using geos::geom::CoordinateSequence;
using geos::geom::PrecisionModel;
namespace geos {
namespace operation { // geos.operation
namespace buffer { // geos.operation.buffer
/**
* \class OffsetCurveBuilder
*
* \brief
* 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 PrecisionModel.
*
* Note: this may not produce correct results if the input
* contains repeated or invalid points.
* Repeated points should be removed before calling.
* See removeRepeatedAndInvalidPoints.
*/
class GEOS_DLL OffsetCurveBuilder {
public:
/*
* @param 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.
*/
OffsetCurveBuilder(
const PrecisionModel* newPrecisionModel,
const BufferParameters& nBufParams)
: distance(0.0)
, precisionModel(newPrecisionModel)
, bufParams(nBufParams)
{}
/** \brief
* Gets the buffer parameters being used to generate the curve.
*
* @return the buffer parameters being used
*/
const BufferParameters&
getBufferParameters() const
{
return bufParams;
}
/**
* 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
*
* @param distance the offset curve distance
* @return true if the offset curve is empty
*/
bool isLineOffsetEmpty(double distance);
/** \brief
* 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).
*
* @param inputPts input points
* @param distance offset distance
* @param lineList the std::vector to which the newly created
* CoordinateSequences will be pushed_back.
* Caller is responsible to delete these new elements.
*/
void getLineCurve(const CoordinateSequence* inputPts,
double distance,
std::vector<CoordinateSequence*>& lineList);
/**
* This method handles single points as well as LineStrings.
* LineStrings are assumed <b>not</b> to be closed (the function will not
* fail for closed lines, but will generate superfluous line caps).
*
* @param inputPts the vertices of the line to offset
* @param pDistance the offset distance
*
* @return a Coordinate array representing the curve
* or null if the curve is empty
*/
std::unique_ptr<CoordinateSequence> getLineCurve(
const CoordinateSequence* inputPts, double pDistance);
/** \brief
* 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).
*
* @param inputPts input points
* @param distance offset distance
* @param lineList the std::vector to which newly created
* CoordinateSequences will be pushed_back.
* Caller will be responsible to delete them.
* @param leftSide indicates that the left side buffer will be
* obtained/skipped
* @param rightSide indicates that the right side buffer will
* be obtained/skipped
*
* @note This is a GEOS extension.
*/
void getSingleSidedLineCurve(const CoordinateSequence* inputPts,
double distance, std::vector<CoordinateSequence*>& lineList,
bool leftSide, bool rightSide) ;
/** \brief
* This method handles the degenerate cases of single points and lines,
* as well as rings.
*
* @param inputPts input points
* @param side a [Position](@ref geom::Position)
* @param distance offset distance
* @param lineList the std::vector to which CoordinateSequences will
* be pushed_back
*/
void getRingCurve(const CoordinateSequence* inputPts, int side,
double distance,
std::vector<CoordinateSequence*>& lineList);
/**
* This method handles the degenerate cases of single points and lines,
* as well as valid rings.
*
* @param inputPts the coordinates of the ring (must not contain repeated points)
* @param side side the side Position of the ring on which to construct the buffer line
* @param pDistance the positive distance at which to create the offset
* @return a Coordinate array representing the curve,
* or null if the curve is empty
*/
std::unique_ptr<CoordinateSequence> getRingCurve(
const CoordinateSequence* inputPts,
int side, double pDistance);
void getOffsetCurve(const CoordinateSequence* inputPts,
double p_distance,
std::vector<CoordinateSequence*>& lineList);
std::unique_ptr<CoordinateSequence> getOffsetCurve(
const CoordinateSequence* inputPts,
double pDistance);
private:
double distance;
const PrecisionModel* precisionModel;
const BufferParameters& bufParams;
/** \brief
* 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.
*/
static const double SIMPLIFY_FACTOR; // 100.0;
/** \brief
* Computes the distance tolerance to use during input
* line simplification.
*
* @param bufDistance the buffer distance
* @return the simplification tolerance
*/
double simplifyTolerance(double bufDistance);
void computeLineBufferCurve(const CoordinateSequence& inputPts,
OffsetSegmentGenerator& segGen);
void computeSingleSidedBufferCurve(const CoordinateSequence& inputPts,
bool isRightSide,
OffsetSegmentGenerator& segGen);
void computeRingBufferCurve(const CoordinateSequence& inputPts,
int side, OffsetSegmentGenerator& segGen);
void computePointCurve(const geom::Coordinate& pt,
OffsetSegmentGenerator& segGen);
void computeOffsetCurve(
const CoordinateSequence* inputPts,
bool isRightSide,
OffsetSegmentGenerator& segGen);
// Declare type as noncopyable
OffsetCurveBuilder(const OffsetCurveBuilder& other) = delete;
OffsetCurveBuilder& operator=(const OffsetCurveBuilder& rhs) = delete;
};
} // namespace geos::operation::buffer
} // namespace geos::operation
} // namespace geos
#ifdef _MSC_VER
#pragma warning(pop)
#endif