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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
62 lines
1.7 KiB
C++
62 lines
1.7 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_BEZIER_H
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#define QWT_BEZIER_H
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#include "qwt_global.h"
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class QPointF;
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class QPolygonF;
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/*!
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\brief An implementation of the de Casteljau’s Algorithm for interpolating
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Bézier curves
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The flatness criterion for terminating the subdivision is based on
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"Piecewise Linear Approximation of Bézier Curves" by
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Roger Willcocks ( http://www.rops.org )
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This article explains the maths behind in a very nice way:
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https://jeremykun.com/2013/05/11/bezier-curves-and-picasso
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*/
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class QWT_EXPORT QwtBezier
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{
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public:
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QwtBezier( double tolerance = 0.5 );
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~QwtBezier();
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void setTolerance( double tolerance );
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double tolerance() const;
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QPolygonF toPolygon( const QPointF& p1, const QPointF& cp1,
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const QPointF& cp2, const QPointF& p2 ) const;
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void appendToPolygon( const QPointF& p1, const QPointF& cp1,
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const QPointF& cp2, const QPointF& p2, QPolygonF& polygon ) const;
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static QPointF pointAt( const QPointF& p1, const QPointF& cp1,
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const QPointF& cp2, const QPointF& p2, double t );
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private:
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double m_tolerance;
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double m_flatness;
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};
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/*!
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\return Tolerance, that is used as criterion for the subdivision
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\sa setTolerance()
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*/
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inline double QwtBezier::tolerance() const
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{
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return m_tolerance;
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}
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#endif
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