/**********************************************************************
*
* GEOS - Geometry Engine Open Source
* http://geos.osgeo.org
*
* Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
* Copyright (C) 2005-2006 Refractions Research Inc.
* Copyright (C) 2001-2002 Vivid Solutions 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: linearref/LengthIndexedLine.java r463
*
**********************************************************************/
#pragma once
#include <geos/export.h>
#include <geos/geom/Coordinate.h>
#include <geos/geom/Geometry.h>
#include <geos/linearref/LinearLocation.h>
namespace geos {
namespace linearref { // geos::linearref
/** \brief
* Supports linear referencing along a linear geom::Geometry
* using the length along the line as the index.
*
* Negative length values are taken as measured in the reverse direction
* from the end of the geometry.
* Out-of-range index values are handled by clamping
* them to the valid range of values.
* Non-simple lines (i.e. which loop back to cross or touch
* themselves) are supported.
*/
class GEOS_DLL LengthIndexedLine {
private:
const geom::Geometry* linearGeom;
LinearLocation locationOf(double index) const;
LinearLocation locationOf(double index, bool resolveLower) const;
double positiveIndex(double index) const;
public:
/** \brief
* Constructs an object which allows a linear [Geometry](@ref geom::Geometry)
* to be linearly referenced using length as an index.
*
* @param linearGeom the linear geometry to reference along
*/
LengthIndexedLine(const geom::Geometry* linearGeom);
/** \brief
* Computes the [Coordinate](@ref geom::Coordinate) for the point
* on the line at the given index.
*
* If the index is out of range the first or last point on the
* line will be returned.
* The Z-ordinate of the computed point will be interpolated from
* the Z-ordinates of the line segment containing it, if they exist.
*
* @param index the index of the desired point
* @return the Coordinate at the given index
*/
geom::Coordinate extractPoint(double index) const;
/**
* \brief
* Computes the [Coordinate](@ref geom::Coordinate) for the point
* on the line at the given index, offset by the given distance.
*
* If the index is out of range the first or last point on the
* line will be returned.
* The computed point is offset to the left of the line if the
* offset distance is positive, to the right if negative.
*
* The Z-ordinate of the computed point will be interpolated from
* the Z-ordinates of the line segment containing it, if they exist.
*
* @param index the index of the desired point
* @param offsetDistance the distance the point is offset from the segment
* (positive is to the left, negative is to the right)
* @return the Coordinate at the given index
*/
geom::Coordinate extractPoint(double index, double offsetDistance) const;
/** \brief
* Computes the [LineString](@ref geom::LineString) for the interval
* on the line between the given indices.
*
* If the endIndex lies before the startIndex,
* the computed geometry is reversed.
*
* @param startIndex the index of the start of the interval
* @param endIndex the index of the end of the interval
* @return the linear interval between the indices
*/
std::unique_ptr<geom::Geometry> extractLine(double startIndex, double endIndex) const;
/** \brief
* Computes the minimum index for a point on the line.
*
* If the line is not simple (i.e. loops back on itself)
* a single point may have more than one possible index.
* In this case, the smallest index is returned.
*
* The supplied point does not *necessarily* have to lie precisely
* on the line, but if it is far from the line the accuracy and
* performance of this function is not guaranteed.
* Use {@link #project} to compute a guaranteed result for points
* which may be far from the line.
*
* @param pt a point on the line
* @return the minimum index of the point
*
* @see project
*/
double indexOf(const geom::Coordinate& pt) const;
/** \brief
* Finds the index for a point on the line which is
* greater than the given index.
*
* If no such index exists, returns `minIndex`.
* This method can be used to determine all indexes for
* a point which occurs more than once on a non-simple line.
* It can also be used to disambiguate cases where the given point lies
* slightly off the line and is equidistant from two different
* points on the line.
*
* The supplied point does not `*necessarily* have to lie precisely
* on the line, but if it is far from the line the accuracy and
* performance of this function is not guaranteed.
* Use {@link #project} to compute a guaranteed result for points
* which may be far from the line.
*
* @param pt a point on the line
* @param minIndex the value the returned index must be greater than
* @return the index of the point greater than the given minimum index
*
* @see project
*/
double indexOfAfter(const geom::Coordinate& pt, double minIndex) const;
/** \brief
* Computes the indices for a subline of the line.
*
* (The subline must **conform** to the line; that is,
* all vertices in the subline (except possibly the first and last)
* must be vertices of the line and occur in the same order).
*
* @param subLine a subLine of the line
* @return a pair of indices for the start and end of the subline.
*/
double* indicesOf(const geom::Geometry* subLine) const;
/** \brief
* Computes the index for the closest point on the line to the given point.
*
* If more than one point has the closest distance the first one along the line
* is returned.
* (The point does not necessarily have to lie precisely on the line.)
*
* @param pt a point on the line
* @return the index of the point
*/
double project(const geom::Coordinate& pt) const;
/** \brief
* Returns the index of the start of the line
* @return the start index
*/
double getStartIndex() const;
/** \brief
* Returns the index of the end of the line
* @return the end index
*/
double getEndIndex() const;
/** \brief
* Tests whether an index is in the valid index range for the line.
*
* @param index the index to test
* @return `true` if the index is in the valid range
*/
bool isValidIndex(double index) const;
/** \brief
* Computes a valid index for this line by clamping the given index
* to the valid range of index values.
*
* @return a valid index value
*/
double clampIndex(double index) const;
};
}
}