A spline with C1 continuity 更多...

#include <qwt_spline_local.h>

类 QwtSplineLocal 继承关系图:

Public 类型
enum	Type { Cardinal , ParabolicBlending , Akima , PChip }
	Spline interpolation type 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
	QwtSplineLocal (Type type)
	Constructor with spline type

	~QwtSplineLocal () override
	Destructor

Type	type () const
	Get spline type

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

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

virtual QVector< QLineF >	bezierControlLines (const QPolygonF &) 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

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

	~QwtSplineC1 () override
	Destructor

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

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

详细描述

A spline with C1 continuity

QwtSplineLocal offers several standard algorithms for interpolating a curve with polynomials having C1 continuity at the control points. All algorithms are local in a sense, that changing one control point only few polynomials.

成员枚举类型说明

◆ Type

enum QwtSplineLocal::Type

Spline interpolation type

All type of spline interpolations are lightweight algorithms calculating the slopes at a point by looking 1 or 2 points back and ahead.

枚举值
Cardinal	A cardinal spline The cardinal spline interpolation is a very cheap calculation with a locality of 1.
ParabolicBlending	Parabolic blending is a cheap calculation with a locality of 1. Sometimes it is also called Cubic Bessel interpolation.
Akima	The algorithm of H.Akima is a calculation with a locality of 2.
PChip	Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) is an algorithm that is popular because of being offered by MATLAB. It preserves the shape of the data and respects monotonicity. It has a locality of 1.

构造及析构函数说明

◆ QwtSplineLocal()

QwtSplineLocal::QwtSplineLocal ( Type type )

explicit

Constructor with spline type

Constructor

参数

[in] type Spline type, specifying the type of interpolation

参见: type()

成员函数说明

◆ bezierControlLines()

QVector< QLineF > QwtSplineLocal::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

points Control points

返回: Control points of the interpolating Bezier curves

重载 QwtSplineC1 .

◆ locality()

uint QwtSplineLocal::locality ( ) const

overridevirtual

Get locality (number of points used for calculation)

Get the locality of the spline interpolation

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

The Cardinal, ParabolicBlending and PChip algorithms have a locality of 1, while the Akima interpolation has a locality of 2.

返回: 1 or 2.

重载 QwtSpline .

◆ painterPath()

QPainterPath QwtSplineLocal::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

points Control points

返回: Painter path, that can be rendered by QPainter

重载 QwtSplineC1 .

◆ polynomials()

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

overridevirtual

Get polynomials from polygon

Calculate the interpolating polynomials for a non parametric spline

参数

points Control points

返回: Interpolating polynomials

注解: The x coordinates need to be increasing or decreasing; The implementation simply calls QwtSplineC1::polynomials(), but is intended to be replaced by a one pass calculation some day.

重载 QwtSplineC1 .

◆ slopes()

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

overridevirtual

Get slopes at control points

Find the first 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

注解: The x coordinates need to be increasing or decreasing

实现了 QwtSplineC1.

◆ type()

QwtSplineLocal::Type QwtSplineLocal::type ( ) const

Get spline type

返回: Spline type, specifying the type of interpolation

该类的文档由以下文件生成:

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

Public 类型

Public 成员函数

详细描述

成员枚举类型说明

◆ Type

构造及析构函数说明

◆ QwtSplineLocal()

成员函数说明

◆ bezierControlLines()

◆ locality()

◆ painterPath()

◆ polynomials()

◆ slopes()

◆ type()