forked from mia/Aegisub
81 lines
2.8 KiB
C++
81 lines
2.8 KiB
C++
//----------------------------------------------------------------------------
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// Anti-Grain Geometry (AGG) - Version 2.5
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// A high quality rendering engine for C++
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// Copyright (C) 2002-2006 Maxim Shemanarev
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// Contact: mcseem@antigrain.com
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// mcseemagg@yahoo.com
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// http://antigrain.com
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//
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// AGG is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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//
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// AGG is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with AGG; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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// MA 02110-1301, USA.
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//----------------------------------------------------------------------------
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#ifndef AGG_bcspline_INCLUDED
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#define AGG_bcspline_INCLUDED
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#include "agg_array.h"
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namespace agg
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{
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//----------------------------------------------------------------bcspline
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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_bcspline.cpp
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//------------------------------------------------------------------------
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class bcspline
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{
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public:
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bcspline();
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bcspline(int num);
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bcspline(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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bcspline(const bcspline&);
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const bcspline& operator = (const bcspline&);
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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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