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33fc476d89
* require qwt >=6.2 (and fallback to internal 6.3 if system's qwt doesn't suffice) * debian doesn't have qwt for Qt6 and won't have it for trixie
55 lines
1.8 KiB
C++
55 lines
1.8 KiB
C++
/******************************************************************************
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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_CUBIC_H
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#define QWT_SPLINE_CUBIC_H
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#include "qwt_global.h"
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#include "qwt_spline.h"
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/*!
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\brief A cubic spline
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A cubic spline is a spline with C2 continuity at all control points.
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It is a non local spline, what means that all polynomials are changing
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when one control point has changed.
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The implementation is based on the fact, that the continuity condition
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means an equation with 3 unknowns for 3 adjacent points. The equation
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system can be resolved by defining start/end conditions, that allow
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substituting of one of the unknowns for the start/end equations.
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Resolving the equation system is a 2 pass algorithm, requiring more CPU costs
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than all other implemented type of splines.
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\todo The implementation is not numerical stable
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*/
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class QWT_EXPORT QwtSplineCubic : public QwtSplineC2
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{
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public:
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QwtSplineCubic();
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virtual ~QwtSplineCubic();
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virtual uint locality() const QWT_OVERRIDE;
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virtual QPainterPath painterPath( const QPolygonF& ) const QWT_OVERRIDE;
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virtual QVector< QLineF > bezierControlLines( const QPolygonF& points ) const QWT_OVERRIDE;
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// calculating the parametric equations
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virtual QVector< QwtSplinePolynomial > polynomials( const QPolygonF& ) const QWT_OVERRIDE;
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virtual QVector< double > slopes( const QPolygonF& ) const QWT_OVERRIDE;
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virtual QVector< double > curvatures( const QPolygonF& ) const QWT_OVERRIDE;
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private:
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class PrivateData;
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PrivateData* m_data;
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};
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#endif
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