QwtSplineLocal - A spline with C1 continuity.
NAME SYNOPSIS Public Types Public Member Functions Detailed Description Member Enumeration Documentation enum QwtSplineLocal::Type Constructor & Destructor Documentation QwtSplineLocal::QwtSplineLocal (Type type) QwtSplineLocal::˜QwtSplineLocal () [virtual] Member Function Documentation QVector< QLineF > QwtSplineLocal::bezierControlLines (const QPolygonF &points) const [override], [virtual] uint QwtSplineLocal::locality () const [override], [virtual] QPainterPath QwtSplineLocal::painterPath (const QPolygonF & points) const[override], [virtual] QVector< QwtSplinePolynomial > QwtSplineLocal::polynomials (const QPolygonF& points) const [override], [virtual] QVector< double > QwtSplineLocal::slopes (const QPolygonF & points) const[override], [virtual] QwtSplineLocal::Type QwtSplineLocal::type () const AuthorNAME
QwtSplineLocal − A spline with C1 continuity.
SYNOPSIS
#include <qwt_spline_local.h>
Inherits QwtSplineC1.
Public Types
enum
Type { Cardinal, ParabolicBlending,
Akima, PChip }
Spline interpolation type.
Public Types inherited from QwtSpline
enum BoundaryType {
ConditionalBoundaries, PeriodicPolygon,
ClosedPolygon }
enum BoundaryPosition { AtBeginning,
AtEnd }
enum BoundaryCondition { Clamped1,
Clamped2, Clamped3, LinearRunout }
Boundary condition.
Public Member Functions
QwtSplineLocal
(Type type)
Constructor.
virtual ˜QwtSplineLocal ()
Destructor.
Type type () const
virtual uint locality () const override
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 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.
Public Member Functions inherited from QwtSplineC1
QwtSplineC1 ()
Constructor.
virtual ˜QwtSplineC1 ()
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
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 override
Interpolate a curve by a polygon.
Public Member Functions inherited from QwtSpline
QwtSpline ()
Constructor.
virtual ˜QwtSpline ()
Destructor.
void setParametrization (int type)
void setParametrization
(QwtSplineParametrization *)
const QwtSplineParametrization *
parametrization () const
void setBoundaryType (BoundaryType)
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.
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
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.
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
type Spline type, specifying the type of interpolation
See also
type()
Definition at line 450 of file qwt_spline_local.cpp.
QwtSplineLocal::˜QwtSplineLocal () [virtual]
Destructor.
Definition at line 461 of file qwt_spline_local.cpp.
Member Function Documentation
QVector< QLineF > QwtSplineLocal::bezierControlLines (const QPolygonF &points) const [override], [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
Reimplemented from QwtSplineC1.
Definition at line 502 of file qwt_spline_local.cpp.
uint QwtSplineLocal::locality () const [override], [virtual]
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.
Returns
1 or 2.
Reimplemented from QwtSpline.
Definition at line 552 of file qwt_spline_local.cpp.
QPainterPath QwtSplineLocal::painterPath (const QPolygonF & points) const[override], [virtual]
Interpolate a curve with Bezier curves. Interpolates a polygon piecewise with cubic Bezier curves and returns them as QPainterPath.
Parameters
points Control points
Returns
Painter path, that can be rendered by QPainter
Reimplemented from QwtSplineC1.
Definition at line 482 of file qwt_spline_local.cpp.
QVector< QwtSplinePolynomial > QwtSplineLocal::polynomials (const QPolygonF& points) const [override], [virtual]
Calculate the interpolating polynomials for a non parametric spline.
Parameters
points Control 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 537 of file qwt_spline_local.cpp.
QVector< double > QwtSplineLocal::slopes (const QPolygonF & points) const[override], [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
Implements QwtSplineC1.
Definition at line 521 of file qwt_spline_local.cpp.
QwtSplineLocal::Type QwtSplineLocal::type () const
Returns
Spline type, specifying the type of interpolation
Definition at line 468 of file qwt_spline_local.cpp.
Author
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