1 | /* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
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2 | * Qwt Widget Library
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3 | * Copyright (C) 1997 Josef Wilgen
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4 | * Copyright (C) 2002 Uwe Rathmann
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5 | *
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6 | * This library is free software; you can redistribute it and/or
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7 | * modify it under the terms of the Qwt License, Version 1.0
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8 | *****************************************************************************/
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9 |
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10 | #ifndef QWT_SPLINE_H
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11 | #define QWT_SPLINE_H
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12 |
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13 | #include "qwt_global.h"
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14 | #include "qwt_double_rect.h"
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15 |
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16 | #if QT_VERSION >= 0x040000
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17 | #include <QPolygonF>
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18 | #else
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19 | #include "qwt_array.h"
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20 | #endif
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21 |
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22 | // MOC_SKIP_BEGIN
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23 |
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24 | #if defined(QWT_TEMPLATEDLL)
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25 |
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26 | #if QT_VERSION < 0x040000
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27 | #ifndef QWTARRAY_TEMPLATE_QWTDOUBLEPOINT // by mjo3
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28 | #define QWTARRAY_TEMPLATE_QWTDOUBLEPOINT
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29 | template class QWT_EXPORT QwtArray<QwtDoublePoint>;
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30 | #endif //end of QWTARRAY_TEMPLATE_QWTDOUBLEPOINT
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31 | #endif
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32 |
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33 | #endif
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34 |
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35 | // MOC_SKIP_END
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36 |
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37 | /*!
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38 | \brief A class for spline interpolation
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39 |
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40 | The QwtSpline class is used for cubical spline interpolation.
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41 | Two types of splines, natural and periodic, are supported.
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42 |
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43 | \par Usage:
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44 | <ol>
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45 | <li>First call setPoints() to determine the spline coefficients
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46 | for a tabulated function y(x).
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47 | <li>After the coefficients have been set up, the interpolated
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48 | function value for an argument x can be determined by calling
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49 | QwtSpline::value().
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50 | </ol>
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51 |
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52 | \par Example:
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53 | \code
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54 | #include <qwt_spline.h>
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55 |
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56 | QPolygonF interpolate(const QPolygonF& points, int numValues)
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57 | {
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58 | QwtSpline spline;
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59 | if ( !spline.setPoints(points) )
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60 | return points;
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61 |
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62 | QPolygonF interpolatedPoints(numValues);
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63 |
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64 | const double delta =
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65 | (points[numPoints - 1].x() - points[0].x()) / (points.size() - 1);
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66 | for(i = 0; i < points.size(); i++) / interpolate
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67 | {
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68 | const double x = points[0].x() + i * delta;
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69 | interpolatedPoints[i].setX(x);
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70 | interpolatedPoints[i].setY(spline.value(x));
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71 | }
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72 | return interpolatedPoints;
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73 | }
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74 | \endcode
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75 | */
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76 |
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77 | class QWT_EXPORT QwtSpline
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78 | {
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79 | public:
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80 | //! Spline type
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81 | enum SplineType
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82 | {
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83 | Natural,
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84 | Periodic
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85 | };
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86 |
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87 | QwtSpline();
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88 | QwtSpline( const QwtSpline & );
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89 |
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90 | ~QwtSpline();
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91 |
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92 | QwtSpline &operator=( const QwtSpline & );
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93 |
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94 | void setSplineType(SplineType);
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95 | SplineType splineType() const;
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96 |
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97 | #if QT_VERSION < 0x040000
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98 | bool setPoints(const QwtArray<QwtDoublePoint>& points);
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99 | QwtArray<QwtDoublePoint> points() const;
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100 | #else
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101 | bool setPoints(const QPolygonF& points);
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102 | QPolygonF points() const;
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103 | #endif
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104 |
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105 | void reset();
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106 |
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107 | bool isValid() const;
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108 | double value(double x) const;
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109 |
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110 | const QwtArray<double> &coefficientsA() const;
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111 | const QwtArray<double> &coefficientsB() const;
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112 | const QwtArray<double> &coefficientsC() const;
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113 |
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114 | protected:
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115 |
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116 | #if QT_VERSION < 0x040000
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117 | bool buildNaturalSpline(
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118 | const QwtArray<QwtDoublePoint> &);
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119 | bool buildPeriodicSpline(
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120 | const QwtArray<QwtDoublePoint> &);
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121 | #else
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122 | bool buildNaturalSpline(const QPolygonF &);
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123 | bool buildPeriodicSpline(const QPolygonF &);
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124 | #endif
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125 |
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126 | class PrivateData;
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127 | PrivateData *d_data;
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128 | };
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129 |
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130 | #endif
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