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//----------------------------------------------------------------------------
// Anti-Grain Geometry (AGG) - Version 2.5
// A high quality rendering engine for C++
// Copyright (C) 2002-2006 Maxim Shemanarev
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://antigrain.com
//
// AGG is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// AGG is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with AGG; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
// MA 02110-1301, USA.
//----------------------------------------------------------------------------
#ifndef AGG_BSPLINE_INCLUDED
#define AGG_BSPLINE_INCLUDED
#include "agg_array.h"
namespace agg
{
//----------------------------------------------------------------bspline
// A very simple class of Bi-cubic Spline interpolation.
// First call init(num, x[], y[]) where num - number of source points,
// x, y - arrays of X and Y values respectively. Here Y must be a function
// of X. It means that all the X-coordinates must be arranged in the ascending
// order.
// Then call get(x) that calculates a value Y for the respective X.
// The class supports extrapolation, i.e. you can call get(x) where x is
// outside the given with init() X-range. Extrapolation is a simple linear
// function.
//
// See Implementation agg_bspline.cpp
//------------------------------------------------------------------------
class bspline
{
public:
bspline();
bspline(int num);
bspline(int num, const double* x, const double* y);
void init(int num);
void add_point(double x, double y);
void prepare();
void init(int num, const double* x, const double* y);
double get(double x) const;
double get_stateful(double x) const;
private:
bspline(const bspline&);
const bspline& operator = (const bspline&);
static void bsearch(int n, const double *x, double x0, int *i);
double extrapolation_left(double x) const;
double extrapolation_right(double x) const;
double interpolation(double x, int i) const;
int m_max;
int m_num;
double* m_x;
double* m_y;
pod_array<double> m_am;
mutable int m_last_idx;
};
}
#endif
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