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/* -*- 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 "qwt_double_rect.h"
#if QT_VERSION >= 0x040000
#include <QPolygonF>
#else
#include "qwt_array.h"
#endif
// MOC_SKIP_BEGIN
#if defined(QWT_TEMPLATEDLL)
#if QT_VERSION < 0x040000
#ifndef QWTARRAY_TEMPLATE_QWTDOUBLEPOINT // by mjo3
#define QWTARRAY_TEMPLATE_QWTDOUBLEPOINT
template class QWT_EXPORT QwtArray<QwtDoublePoint>;
#endif //end of QWTARRAY_TEMPLATE_QWTDOUBLEPOINT
#endif
#endif
// MOC_SKIP_END
/*!
\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:
enum SplineType
{
Natural,
Periodic
};
QwtSpline();
QwtSpline( const QwtSpline & );
~QwtSpline();
QwtSpline &operator=( const QwtSpline & );
void setSplineType(SplineType);
SplineType splineType() const;
#if QT_VERSION < 0x040000
bool setPoints(const QwtArray<QwtDoublePoint>& points);
QwtArray<QwtDoublePoint> points() const;
#else
bool setPoints(const QPolygonF& points);
QPolygonF points() const;
#endif
void reset();
bool isValid() const;
double value(double x) const;
protected:
#if QT_VERSION < 0x040000
bool buildNaturalSpline(
const QwtArray<QwtDoublePoint> &);
bool buildPeriodicSpline(
const QwtArray<QwtDoublePoint> &);
#else
bool buildNaturalSpline(const QPolygonF &);
bool buildPeriodicSpline(const QPolygonF &);
#endif
class PrivateData;
PrivateData *d_data;
};
#endif