Base class for spline interpolations providing a first order parametric continuity ( C1 ) between adjoining curves. More...

#include <qwt_spline.h>

Inheritance diagram for QwtSplineC1:

Public Member Functions
	QwtSplineC1 ()
	Constructor.

virtual	~QwtSplineC1 ()
	Destructor.

virtual QPainterPath	painterPath (const QPolygonF &) const QWT_OVERRIDE
	Calculate an interpolated painter path.

virtual QVector< QLineF >	bezierControlLines (const QPolygonF &) const QWT_OVERRIDE
	Interpolate a curve with Bezier curves.

virtual QPolygonF	equidistantPolygon (const QPolygonF &, double distance, bool withNodes) const QWT_OVERRIDE
	Find an interpolated polygon with "equidistant" points.

virtual QVector< QwtSplinePolynomial >	polynomials (const QPolygonF &) const
	Calculate the interpolating polynomials for a non parametric spline.

virtual QVector< double >	slopes (const QPolygonF &) const =0
	Find the first derivative at the control points.

virtual double	slopeAtBeginning (const QPolygonF &, double slopeNext) const

virtual double	slopeAtEnd (const QPolygonF &, double slopeBefore) const

Public Member Functions inherited from QwtSplineG1
	QwtSplineG1 ()
	Constructor.

virtual	~QwtSplineG1 ()
	Destructor.

Public Member Functions inherited from QwtSplineInterpolating
	QwtSplineInterpolating ()
	Constructor.

virtual	~QwtSplineInterpolating ()
	Destructor.

virtual QPolygonF	polygon (const QPolygonF &, double tolerance) const QWT_OVERRIDE
	Interpolate a curve by a polygon.

Public Member Functions inherited from QwtSpline
	QwtSpline ()
	Constructor.

virtual	~QwtSpline ()
	Destructor.

void	setParametrization (int type)
	Define the parametrization for a parametric spline approximation The default setting is a chordal parametrization.

void	setParametrization (QwtSplineParametrization *)
	Define the parametrization for a parametric spline approximation The default setting is a chordal parametrization.

const QwtSplineParametrization *	parametrization () const

void	setBoundaryType (BoundaryType)
	Define the boundary type for the endpoints of the approximating spline.

BoundaryType	boundaryType () const

void	setBoundaryValue (BoundaryPosition, double value)
	Define the boundary value.

double	boundaryValue (BoundaryPosition) const

void	setBoundaryCondition (BoundaryPosition, int condition)
	Define the condition for an endpoint of the spline.

int	boundaryCondition (BoundaryPosition) const

void	setBoundaryConditions (int condition, double valueBegin=0.0, double valueEnd=0.0)
	Define the condition at the endpoints of a spline.

virtual uint	locality () const
	The locality of an spline interpolation identifies how many adjacent polynomials are affected, when changing the position of one point.

Additional Inherited Members
Public Types inherited from QwtSpline
enum	BoundaryType { ConditionalBoundaries , PeriodicPolygon , ClosedPolygon }
	Boundary type specifying the spline at its endpoints. More...

enum	BoundaryPosition { AtBeginning , AtEnd }
	position of a boundary condition More...

enum	BoundaryCondition { Clamped1 , Clamped2 , Clamped3 , LinearRunout }
	Boundary condition. More...

Detailed Description

Base class for spline interpolations providing a first order parametric continuity ( C1 ) between adjoining curves.

All interpolations with C1 continuity are based on rules for finding the 1. derivate at some control points.

In case of non parametric splines those points are the curve points, while for parametric splines the calculation is done twice using a parameter value t.

See also: QwtSplineParametrization

Constructor & Destructor Documentation

◆ QwtSplineC1()

QwtSplineC1::QwtSplineC1 ( )

Constructor.

The default setting is a non closing spline with no parametrization ( QwtSplineParametrization::ParameterX ).

See also: QwtSpline::setParametrization(), QwtSpline::setBoundaryType()

Member Function Documentation

◆ bezierControlLines()

QVector< QLineF > QwtSplineC1::bezierControlLines ( const QPolygonF & points ) const

virtual

Interpolate a curve with Bezier curves.

Interpolates a polygon piecewise with cubic Bezier curves and returns the 2 control points of each curve as QLineF.

Parameters

points Control points

Returns: Control points of the interpolating Bezier curves

Implements QwtSplineInterpolating.

Reimplemented in QwtSplineC2, QwtSplineLocal, and QwtSplineCubic.

◆ equidistantPolygon()

QPolygonF QwtSplineC1::equidistantPolygon	(	const QPolygonF &	points,
		double	distance,
		bool	withNodes
	)		const

virtual

Find an interpolated polygon with "equidistant" points.

The implementation is optimzed for non parametric curves ( QwtSplineParametrization::ParameterX ) and falls back to QwtSpline::equidistantPolygon() otherwise.

Parameters

points	Control nodes of the spline
distance	Distance between 2 points according to the parametrization
withNodes	When true, also add the control nodes ( even if not being equidistant )

Returns: Interpolating polygon

See also: QwtSpline::equidistantPolygon()

Reimplemented from QwtSplineInterpolating.

Reimplemented in QwtSplineC2.

◆ painterPath()

QPainterPath QwtSplineC1::painterPath ( const QPolygonF & points ) const

virtual

Calculate an interpolated painter path.

Interpolates a polygon piecewise into cubic Bezier curves and returns them as QPainterPath.

The implementation calculates the slopes at the control points and converts them into painter path elements in an additional loop.

Parameters

points Control points

Returns: QPainterPath Painter path, that can be rendered by QPainter

Note: Derived spline classes might overload painterPath() to avoid the extra loops for converting results into a QPainterPath

Reimplemented from QwtSplineInterpolating.

Reimplemented in QwtSplineC2, QwtSplineCubic, and QwtSplineLocal.

◆ polynomials()

QVector< QwtSplinePolynomial > QwtSplineC1::polynomials ( const QPolygonF & points ) const

virtual

Calculate the interpolating polynomials for a non parametric spline.

C1 spline interpolations are based on finding values for the first derivates at the control points. The interpolating polynomials can be calculated from the the first derivates using QwtSplinePolynomial::fromSlopes().

The default implementation is a two pass calculation. In derived classes it might be overloaded by a one pass implementation.

Parameters

points Control points

Returns: Interpolating polynomials

Note: The x coordinates need to be increasing or decreasing

Reimplemented in QwtSplineC2, QwtSplineCubic, and QwtSplineLocal.

◆ slopeAtBeginning()

double QwtSplineC1::slopeAtBeginning	(	const QPolygonF &	points,
		double	slopeNext
	)		const

virtual

Parameters

points	Control points
slopeNext	Value of the first derivative at the second point

Returns: value of the first derivative at the first point

See also: slopeAtEnd(), QwtSpline::boundaryCondition(), QwtSpline::boundaryValue()

◆ slopeAtEnd()

double QwtSplineC1::slopeAtEnd	(	const QPolygonF &	points,
		double	slopeBefore
	)		const

virtual

Parameters

points	Control points
slopeBefore	Value of the first derivative at the point before the last one

Returns: value of the first derivative at the last point

See also: slopeAtBeginning(), QwtSpline::boundaryCondition(), QwtSpline::boundaryValue()

◆ slopes()

QVector< double > QwtSplineC1::slopes ( const QPolygonF & points ) const

pure virtual

Find the first derivative at the control points.

Parameters

points Control nodes of the spline

Returns: Vector with the values of the 2nd derivate at the control points

Note: The x coordinates need to be increasing or decreasing

Implemented in QwtSplineC2, QwtSplineCubic, and QwtSplineLocal.

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

/home/runner/work/QWT/QWT/src/qwt_spline.h
/home/runner/work/QWT/QWT/src/qwt_spline.cpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QwtSplineC1()

Member Function Documentation

◆ bezierControlLines()

◆ equidistantPolygon()

◆ painterPath()

◆ polynomials()

◆ slopeAtBeginning()

◆ slopeAtEnd()

◆ slopes()