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101 lines
2.4 KiB
101 lines
2.4 KiB
/* -*- mode: C++ ; c-file-style: "stroustrup" -*- ***************************** |
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* Qwt Widget Library |
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* Copyright (C) 1997 Josef Wilgen |
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* Copyright (C) 2002 Uwe Rathmann |
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* |
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* This library is free software; you can redistribute it and/or |
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* modify it under the terms of the Qwt License, Version 1.0 |
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*****************************************************************************/ |
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#ifndef QWT_SPLINE_H |
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#define QWT_SPLINE_H |
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#include "qwt_global.h" |
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#include <qpolygon.h> |
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#include <qvector.h> |
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/*! |
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\brief A class for spline interpolation |
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The QwtSpline class is used for cubical spline interpolation. |
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Two types of splines, natural and periodic, are supported. |
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\par Usage: |
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<ol> |
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<li>First call setPoints() to determine the spline coefficients |
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for a tabulated function y(x). |
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<li>After the coefficients have been set up, the interpolated |
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function value for an argument x can be determined by calling |
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QwtSpline::value(). |
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</ol> |
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\par Example: |
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\code |
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#include <qwt_spline.h> |
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QPolygonF interpolate(const QPolygonF& points, int numValues) |
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{ |
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QwtSpline spline; |
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if ( !spline.setPoints(points) ) |
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return points; |
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QPolygonF interpolatedPoints(numValues); |
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const double delta = |
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(points[numPoints - 1].x() - points[0].x()) / (points.size() - 1); |
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for(i = 0; i < points.size(); i++) / interpolate |
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{ |
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const double x = points[0].x() + i * delta; |
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interpolatedPoints[i].setX(x); |
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interpolatedPoints[i].setY(spline.value(x)); |
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} |
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return interpolatedPoints; |
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} |
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\endcode |
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*/ |
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class QWT_EXPORT QwtSpline |
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{ |
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public: |
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//! Spline type |
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enum SplineType |
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{ |
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//! A natural spline |
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Natural, |
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//! A periodic spline |
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Periodic |
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}; |
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QwtSpline(); |
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QwtSpline( const QwtSpline & ); |
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~QwtSpline(); |
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QwtSpline &operator=( const QwtSpline & ); |
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void setSplineType( SplineType ); |
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SplineType splineType() const; |
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bool setPoints( const QPolygonF& points ); |
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QPolygonF points() const; |
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void reset(); |
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bool isValid() const; |
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double value( double x ) const; |
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const QVector<double> &coefficientsA() const; |
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const QVector<double> &coefficientsB() const; |
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const QVector<double> &coefficientsC() const; |
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protected: |
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bool buildNaturalSpline( const QPolygonF & ); |
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bool buildPeriodicSpline( const QPolygonF & ); |
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private: |
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class PrivateData; |
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PrivateData *d_data; |
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}; |
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#endif
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