Base class for spline interpolations with C2 (second order parametric) continuity 更多...

#include <qwt_spline.h>

类 QwtSplineC2 继承关系图:

Public 类型
enum	BoundaryConditionC2 { CubicRunout = LinearRunout + 1 , NotAKnot }
	Boundary condition that requires C2 continuity 更多...

Public 类型继承自 QwtSpline
enum	BoundaryType { ConditionalBoundaries , PeriodicPolygon , ClosedPolygon }
	Boundary type specifying the spline at its endpoints 更多...

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

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

Public 成员函数
	QwtSplineC2 ()
	Constructor

	~QwtSplineC2 () override
	Destructor

virtual QPainterPath	painterPath (const QPolygonF &) const override
	Interpolate a curve with Bezier curves

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

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

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

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

virtual QVector< double >	curvatures (const QPolygonF &) const =0
	Find the second derivative at the control points

Public 成员函数继承自 QwtSplineC1
	QwtSplineC1 ()
	Constructor

	~QwtSplineC1 () override
	Destructor

virtual double	slopeAtBeginning (const QPolygonF &, double slopeNext) const
	Calculate the slope at the beginning of the spline

virtual double	slopeAtEnd (const QPolygonF &, double slopeBefore) const
	Calculate the slope at the end of the spline

Public 成员函数继承自 QwtSplineG1
	QwtSplineG1 ()
	Constructor

	~QwtSplineG1 () override
	Destructor

Public 成员函数继承自 QwtSplineInterpolating
	QwtSplineInterpolating ()
	Constructor

	~QwtSplineInterpolating () override
	Destructor

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

Public 成员函数继承自 QwtSpline
	QwtSpline ()
	Constructor

virtual	~QwtSpline ()
	Destructor

void	setParametrization (int type)
	Set parametrization by type

void	setParametrization (QwtSplineParametrization *)
	Set parametrization object

const QwtSplineParametrization *	parametrization () const
	Get parametrization

void	setBoundaryType (BoundaryType)
	Set boundary type

BoundaryType	boundaryType () const
	Get boundary type

void	setBoundaryValue (BoundaryPosition, double value)
	Set boundary value

double	boundaryValue (BoundaryPosition) const
	Get boundary value

void	setBoundaryCondition (BoundaryPosition, int condition)
	Set boundary condition

int	boundaryCondition (BoundaryPosition) const
	Get boundary condition

void	setBoundaryConditions (int condition, double valueBegin=0.0, double valueEnd=0.0)
	Set boundary conditions for both ends

virtual uint	locality () const
	Get locality (number of points used for calculation)

详细描述

Base class for spline interpolations with C2 (second order parametric) continuity

All interpolations with C2 continuity are based on rules for finding the second derivative at some control points.

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

参见: QwtSplineParametrization

成员枚举类型说明

◆ BoundaryConditionC2

enum QwtSplineC2::BoundaryConditionC2

Boundary condition that requires C2 continuity

参见: QwtSpline::boundaryCondition, QwtSpline::BoundaryCondition

枚举值

CubicRunout

The second derivate at the endpoint is related to the second derivatives at the 2 neighbours: cv[0] := 2.0 * cv[1] - cv[2].

注解: boundaryValue() is ignored

NotAKnot

The 3rd derivate at the endpoint matches the 3rd derivate at its neighbours.

Or in other words: the first/last curve segment extents the polynomial of its neighboured polynomial

注解: boundaryValue() is ignored

构造及析构函数说明

◆ QwtSplineC2()

QwtSplineC2::QwtSplineC2 ( )

Constructor

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

参见: QwtSpline::setParametrization(), QwtSpline::setBoundaryType()

成员函数说明

◆ bezierControlLines()

QVector< QLineF > QwtSplineC2::bezierControlLines ( const QPolygonF & points ) const

overridevirtual

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.

参数

[in] points Control points

返回: Control points of the interpolating Bezier curves

注解: The implementation simply calls QwtSplineC1::bezierControlLines(), but is intended to be replaced by a more efficient implementation that builds the polynomials by the curvatures some day.

重载 QwtSplineC1 .

被 QwtSplineCubic 重载.

◆ curvatures()

QVector< double > QwtSplineC2::curvatures ( const QPolygonF & points ) const

pure virtual

Find the second derivative at the control points

参数

points Control nodes of the spline

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

参见: slopes()

注解: The x coordinates need to be increasing or decreasing

在 QwtSplineCubic 内被实现.

◆ equidistantPolygon()

QPolygonF QwtSplineC2::equidistantPolygon	(	const QPolygonF &	points,
		double	distance,
		bool	withNodes
	)		const

overridevirtual

Find an interpolated polygon with "equidistant" points

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

参数

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

返回: Interpolating polygon

参见: QwtSpline::equidistantPolygon()

重载 QwtSplineC1 .

◆ painterPath()

QPainterPath QwtSplineC2::painterPath ( const QPolygonF & points ) const

overridevirtual

Interpolate a curve with Bezier curves

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

参数

[in] points Control points

返回: Painter path that can be rendered by QPainter

注解: The implementation simply calls QwtSplineC1::painterPath(), but is intended to be replaced by a one-pass calculation some day.

重载 QwtSplineC1 .

被 QwtSplineCubic 重载.

◆ polynomials()

QVector< QwtSplinePolynomial > QwtSplineC2::polynomials ( const QPolygonF & points ) const

overridevirtual

Calculate the interpolating polynomials for a non-parametric spline

C2 spline interpolations are based on finding values for the second derivatives of f at the control points. The interpolating polynomials can be calculated from the second derivatives using QwtSplinePolynomial::fromCurvatures.

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

参数

[in] points Control points

返回: Interpolating polynomials

注解: The x coordinates need to be increasing or decreasing

重载 QwtSplineC1 .

被 QwtSplineCubic 重载.

◆ slopes()

QVector< double > QwtSplineC2::slopes ( const QPolygonF & points ) const

overridevirtual

Find the first derivative at the control points

An implementation calculating the second derivatives and then building the slopes in a second loop. QwtSplineCubic overloads it with a more performant implementation doing it in one loop.

参数

[in] points Control nodes of the spline

返回: Vector with the values of the first derivative at the control points

参见: curvatures()

注解: The x coordinates need to be increasing or decreasing

实现了 QwtSplineC1.

被 QwtSplineCubic 重载.

该类的文档由以下文件生成:

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

Public 类型

Public 成员函数

详细描述

成员枚举类型说明

◆ BoundaryConditionC2

构造及析构函数说明

◆ QwtSplineC2()

成员函数说明

◆ bezierControlLines()

◆ curvatures()

◆ equidistantPolygon()

◆ painterPath()

◆ polynomials()

◆ slopes()