You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
102 lines
2.4 KiB
C
102 lines
2.4 KiB
C
3 weeks ago
|
/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
|
||
|
|
* Qwt Widget Library
|
||
|
|
* Copyright (C) 1997 Josef Wilgen
|
||
|
|
* Copyright (C) 2002 Uwe Rathmann
|
||
|
|
*
|
||
|
|
* This library is free software; you can redistribute it and/or
|
||
|
|
* modify it under the terms of the Qwt License, Version 1.0
|
||
|
|
*****************************************************************************/
|
||
|
|
|
||
|
|
#ifndef QWT_SPLINE_H
|
||
|
|
#define QWT_SPLINE_H
|
||
|
|
|
||
|
|
#include "qwt_global.h"
|
||
|
|
#include <qpolygon.h>
|
||
|
|
#include <qvector.h>
|
||
|
|
|
||
|
|
/*!
|
||
|
|
\brief A class for spline interpolation
|
||
|
|
|
||
|
|
The QwtSpline class is used for cubical spline interpolation.
|
||
|
|
Two types of splines, natural and periodic, are supported.
|
||
|
|
|
||
|
|
\par Usage:
|
||
|
|
<ol>
|
||
|
|
<li>First call setPoints() to determine the spline coefficients
|
||
|
|
for a tabulated function y(x).
|
||
|
|
<li>After the coefficients have been set up, the interpolated
|
||
|
|
function value for an argument x can be determined by calling
|
||
|
|
QwtSpline::value().
|
||
|
|
</ol>
|
||
|
|
|
||
|
|
\par Example:
|
||
|
|
\code
|
||
|
|
#include <qwt_spline.h>
|
||
|
|
|
||
|
|
QPolygonF interpolate(const QPolygonF& points, int numValues)
|
||
|
|
{
|
||
|
|
QwtSpline spline;
|
||
|
|
if ( !spline.setPoints(points) )
|
||
|
|
return points;
|
||
|
|
|
||
|
|
QPolygonF interpolatedPoints(numValues);
|
||
|
|
|
||
|
|
const double delta =
|
||
|
|
(points[numPoints - 1].x() - points[0].x()) / (points.size() - 1);
|
||
|
|
for(i = 0; i < points.size(); i++) / interpolate
|
||
|
|
{
|
||
|
|
const double x = points[0].x() + i * delta;
|
||
|
|
interpolatedPoints[i].setX(x);
|
||
|
|
interpolatedPoints[i].setY(spline.value(x));
|
||
|
|
}
|
||
|
|
return interpolatedPoints;
|
||
|
|
}
|
||
|
|
\endcode
|
||
|
|
*/
|
||
|
|
|
||
|
|
class QWT_EXPORT QwtSpline
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
//! Spline type
|
||
|
|
enum SplineType
|
||
|
|
{
|
||
|
|
//! A natural spline
|
||
|
|
Natural,
|
||
|
|
|
||
|
|
//! A periodic spline
|
||
|
|
Periodic
|
||
|
|
};
|
||
|
|
|
||
|
|
QwtSpline();
|
||
|
|
QwtSpline( const QwtSpline & );
|
||
|
|
|
||
|
|
~QwtSpline();
|
||
|
|
|
||
|
|
QwtSpline &operator=( const QwtSpline & );
|
||
|
|
|
||
|
|
void setSplineType( SplineType );
|
||
|
|
SplineType splineType() const;
|
||
|
|
|
||
|
|
bool setPoints( const QPolygonF& points );
|
||
|
|
QPolygonF points() const;
|
||
|
|
|
||
|
|
void reset();
|
||
|
|
|
||
|
|
bool isValid() const;
|
||
|
|
double value( double x ) const;
|
||
|
|
|
||
|
|
const QVector<double> &coefficientsA() const;
|
||
|
|
const QVector<double> &coefficientsB() const;
|
||
|
|
const QVector<double> &coefficientsC() const;
|
||
|
|
|
||
|
|
protected:
|
||
|
|
bool buildNaturalSpline( const QPolygonF & );
|
||
|
|
bool buildPeriodicSpline( const QPolygonF & );
|
||
|
|
|
||
|
|
private:
|
||
|
|
class PrivateData;
|
||
|
|
PrivateData *d_data;
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif
|