77 lines
2.6 KiB
C++
77 lines
2.6 KiB
C++
//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.4
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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//----------------------------------------------------------------------------
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// Contact: mcseem@antigrain.com
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// mcseemagg@yahoo.com
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// http://www.antigrain.com
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//----------------------------------------------------------------------------
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//
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// class bspline
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//
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//----------------------------------------------------------------------------
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#ifndef AGG_BSPLINE_INCLUDED
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#define AGG_BSPLINE_INCLUDED
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#include "agg_array.h"
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namespace agg
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{
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//----------------------------------------------------------------bspline
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// A very simple class of Bi-cubic Spline interpolation.
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// First call init(num, x[], y[]) where num - number of source points,
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// x, y - arrays of X and Y values respectively. Here Y must be a function
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// of X. It means that all the X-coordinates must be arranged in the ascending
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// order.
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// Then call get(x) that calculates a value Y for the respective X.
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// The class supports extrapolation, i.e. you can call get(x) where x is
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// outside the given with init() X-range. Extrapolation is a simple linear
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// function.
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//
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// See Implementation agg_bspline.cpp
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//------------------------------------------------------------------------
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class bspline
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{
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public:
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bspline();
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bspline(int num);
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bspline(int num, const double* x, const double* y);
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void init(int num);
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void add_point(double x, double y);
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void prepare();
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void init(int num, const double* x, const double* y);
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double get(double x) const;
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double get_stateful(double x) const;
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private:
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bspline(const bspline&);
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const bspline& operator = (const bspline&);
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static void bsearch(int n, const double *x, double x0, int *i);
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double extrapolation_left(double x) const;
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double extrapolation_right(double x) const;
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double interpolation(double x, int i) const;
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int m_max;
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int m_num;
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double* m_x;
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double* m_y;
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pod_array<double> m_am;
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mutable int m_last_idx;
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};
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}
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#endif
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