Public Types | Public Member Functions | Private Attributes | List of all members
QwtSplineLocal Class Reference

A spline with C1 continuity. More...

#include <qwt_spline_local.h>

Inheritance diagram for QwtSplineLocal:
Inheritance graph
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Public Types

enum  Type { Cardinal, ParabolicBlending, Akima, PChip }
 Spline interpolation type. More...
 
- Public Types inherited from QwtSpline
enum  BoundaryCondition { Clamped1, Clamped2, Clamped3, LinearRunout }
 Boundary condition. More...
 
enum  BoundaryPosition { AtBeginning, AtEnd }
 
enum  BoundaryType { ConditionalBoundaries, PeriodicPolygon, ClosedPolygon }
 

Public Member Functions

virtual QVector< QLineF > bezierControlLines (const QPolygonF &) const
 Interpolate a curve with Bezier curves. More...
 
virtual uint locality () const
 
virtual QPainterPath painterPath (const QPolygonF &) const
 Interpolate a curve with Bezier curves. More...
 
virtual QVector< QwtSplinePolynomialpolynomials (const QPolygonF &) const
 Calculate the interpolating polynomials for a non parametric spline. More...
 
 QwtSplineLocal (Type type)
 Constructor. More...
 
virtual QVector< double > slopes (const QPolygonF &) const
 Find the first derivative at the control points. More...
 
Type type () const
 
virtual ~QwtSplineLocal ()
 Destructor. More...
 
- Public Member Functions inherited from QwtSplineC1
virtual QPolygonF equidistantPolygon (const QPolygonF &, double distance, bool withNodes) const
 Find an interpolated polygon with "equidistant" points. More...
 
 QwtSplineC1 ()
 Constructor. More...
 
virtual double slopeAtBeginning (const QPolygonF &, double slopeNext) const
 
virtual double slopeAtEnd (const QPolygonF &, double slopeBefore) const
 
virtual ~QwtSplineC1 ()
 Destructor. More...
 
- Public Member Functions inherited from QwtSplineG1
 QwtSplineG1 ()
 Constructor. More...
 
virtual ~QwtSplineG1 ()
 Destructor. More...
 
- Public Member Functions inherited from QwtSplineInterpolating
virtual QPolygonF polygon (const QPolygonF &, double tolerance) const
 Interpolate a curve by a polygon. More...
 
 QwtSplineInterpolating ()
 Constructor. More...
 
virtual ~QwtSplineInterpolating ()
 Destructor. More...
 
- Public Member Functions inherited from QwtSpline
int boundaryCondition (BoundaryPosition) const
 
BoundaryType boundaryType () const
 
double boundaryValue (BoundaryPosition) const
 
const QwtSplineParametrizationparametrization () const
 
 QwtSpline ()
 Constructor. More...
 
void setBoundaryCondition (BoundaryPosition, int condition)
 Define the condition for an endpoint of the spline. More...
 
void setBoundaryConditions (int condition, double valueBegin=0.0, double valueEnd=0.0)
 Define the condition at the endpoints of a spline. More...
 
void setBoundaryType (BoundaryType)
 
void setBoundaryValue (BoundaryPosition, double value)
 Define the boundary value. More...
 
void setParametrization (int type)
 
void setParametrization (QwtSplineParametrization *)
 
virtual ~QwtSpline ()
 Destructor. More...
 

Private Attributes

const Type d_type
 

Detailed Description

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.

Definition at line 24 of file qwt_spline_local.h.

Member Enumeration Documentation

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.

Enumerator
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.

Definition at line 34 of file qwt_spline_local.h.

Constructor & Destructor Documentation

QwtSplineLocal::QwtSplineLocal ( Type  type)

Constructor.

Parameters
typeSpline type, specifying the type of interpolation
See also
type()

Definition at line 448 of file qwt_spline_local.cpp.

QwtSplineLocal::~QwtSplineLocal ( )
virtual

Destructor.

Definition at line 459 of file qwt_spline_local.cpp.

Member Function Documentation

QVector< QLineF > QwtSplineLocal::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
pointsControl points
Returns
Control points of the interpolating Bezier curves

Reimplemented from QwtSplineC1.

Definition at line 500 of file qwt_spline_local.cpp.

uint QwtSplineLocal::locality ( ) const
virtual

The locality of an spline interpolation identifies how many adjacent polynoms 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.

Returns
1 or 2.

Reimplemented from QwtSpline.

Definition at line 550 of file qwt_spline_local.cpp.

QPainterPath QwtSplineLocal::painterPath ( const QPolygonF &  points) const
virtual

Interpolate a curve with Bezier curves.

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

Parameters
pointsControl points
Returns
Painter path, that can be rendered by QPainter

Reimplemented from QwtSplineC1.

Definition at line 480 of file qwt_spline_local.cpp.

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

Calculate the interpolating polynomials for a non parametric spline.

Parameters
pointsControl points
Returns
Interpolating polynomials
Note
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.

Reimplemented from QwtSplineC1.

Definition at line 535 of file qwt_spline_local.cpp.

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

Find the first derivative at the control points.

Parameters
pointsControl 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

Implements QwtSplineC1.

Definition at line 519 of file qwt_spline_local.cpp.

QwtSplineLocal::Type QwtSplineLocal::type ( ) const
Returns
Spline type, specifying the type of interpolation

Definition at line 466 of file qwt_spline_local.cpp.

Member Data Documentation

const Type QwtSplineLocal::d_type
private

Definition at line 80 of file qwt_spline_local.h.


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


plotjuggler
Author(s): Davide Faconti
autogenerated on Sat Jul 6 2019 03:44:19