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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_GAMMA_FUNCTIONS_INCLUDED
#define AGG_GAMMA_FUNCTIONS_INCLUDED
#include <math.h>
#include "agg_basics.h"
namespace agg
{
//===============================================================gamma_none
struct gamma_none
{
double operator()(double x) const { return x; }
};
//==============================================================gamma_power
class gamma_power
{
public:
gamma_power() : m_gamma(1.0) {}
gamma_power(double g) : m_gamma(g) {}
void gamma(double g) { m_gamma = g; }
double gamma() const { return m_gamma; }
double operator() (double x) const
{
return pow(x, m_gamma);
}
private:
double m_gamma;
};
//==========================================================gamma_threshold
class gamma_threshold
{
public:
gamma_threshold() : m_threshold(0.5) {}
gamma_threshold(double t) : m_threshold(t) {}
void threshold(double t) { m_threshold = t; }
double threshold() const { return m_threshold; }
double operator() (double x) const
{
return (x < m_threshold) ? 0.0 : 1.0;
}
private:
double m_threshold;
};
//============================================================gamma_linear
class gamma_linear
{
public:
gamma_linear() : m_start(0.0), m_end(1.0) {}
gamma_linear(double s, double e) : m_start(s), m_end(e) {}
void set(double s, double e) { m_start = s; m_end = e; }
void start(double s) { m_start = s; }
void end(double e) { m_end = e; }
double start() const { return m_start; }
double end() const { return m_end; }
double operator() (double x) const
{
if(x < m_start) return 0.0;
if(x > m_end) return 1.0;
return (x - m_start) / (m_end - m_start);
}
private:
double m_start;
double m_end;
};
//==========================================================gamma_multiply
class gamma_multiply
{
public:
gamma_multiply() : m_mul(1.0) {}
gamma_multiply(double v) : m_mul(v) {}
void value(double v) { m_mul = v; }
double value() const { return m_mul; }
double operator() (double x) const
{
double y = x * m_mul;
if(y > 1.0) y = 1.0;
return y;
}
private:
double m_mul;
};
}
#endif
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