A cubic spline 更多...

#include <qwt_spline_cubic.h>

类 QwtSplineCubic 继承关系图:

类
class	PrivateData

Public 成员函数
	QwtSplineCubic ()
	Constructor

	~QwtSplineCubic () override
	Destructor

virtual uint	locality () const override
	Get locality (always 0 - non-local)

virtual QPainterPath	painterPath (const QPolygonF &) const override
	Get painter path from polygon

virtual QVector< QLineF >	bezierControlLines (const QPolygonF &points) const override
	Get Bezier control lines

virtual QVector< QwtSplinePolynomial >	polynomials (const QPolygonF &) const override
	Get polynomials from polygon

virtual QVector< double >	slopes (const QPolygonF &) const override
	Get slopes at control points

virtual QVector< double >	curvatures (const QPolygonF &) const override
	Get curvatures at control points

Public 成员函数继承自 QwtSplineC2
	QwtSplineC2 ()
	Constructor

	~QwtSplineC2 () override
	Destructor

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

额外继承的成员函数
Public 类型继承自 QwtSplineC2
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...

详细描述

A cubic spline

A cubic spline is a spline with C2 continuity at all control points. It is a non local spline, where a modification of one control point affects the whole spline.

The implementation is based on the equation system of the second derivatives M(x) of the control points P(x).

QwtSplineCubic offers several algorithms for finding M(x), that are selected by setBoundaryType().

The default setting is a "natural spline" having M(x0) = M(xn) = 0.

参见: QwtSpline::BoundaryType

构造及析构函数说明

◆ QwtSplineCubic()

QwtSplineCubic::QwtSplineCubic ( )

Constructor

The default setting is a non-closing natural spline with no parametrization.

Destructor

成员函数说明

◆ bezierControlLines()

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

overridevirtual

Get Bezier control lines

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()

重载 QwtSplineC2 .

◆ curvatures()

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

overridevirtual

Get curvatures at control points

Find the second derivative at the control points

参数

[in] points Control nodes of the spline

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

参见: slopes()

注解: The x coordinates need to be increasing or decreasing

实现了 QwtSplineC2.

◆ locality()

uint QwtSplineCubic::locality ( ) const

overridevirtual

Get locality (always 0 - non-local)

Get locality

A cubic spline is non-local, where changing one point has an effect on all polynomials.

返回: 0

重载 QwtSpline .

◆ painterPath()

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

overridevirtual

Get painter path from polygon

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()

重载 QwtSplineC2 .

◆ polynomials()

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

overridevirtual

Get polynomials from polygon

Calculate the interpolating polynomials for a non-parametric spline

参数

[in] points Control points

返回: Interpolating polynomials

注解: The x coordinates need to be increasing or decreasing; The implementation simply calls QwtSplineC2::polynomials(), but is intended to be replaced by a one-pass calculation some day.

重载 QwtSplineC2 .

◆ slopes()

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

overridevirtual

Get slopes at control points

Find the first derivative at the control points

In contrast to the QwtSplineC2::slopes implementation, the first derivatives are calculated directly, without calculating the second derivatives first.

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(), QwtSplinePolynomial::fromCurvatures()

注解: The x coordinates need to be increasing or decreasing

重载 QwtSplineC2 .

该类的文档由以下文件生成:

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

类

Public 成员函数

额外继承的成员函数

详细描述

构造及析构函数说明

◆ QwtSplineCubic()

成员函数说明

◆ bezierControlLines()

◆ curvatures()

◆ locality()

◆ painterPath()

◆ polynomials()

◆ slopes()