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+//----------------------------------------------------------------------------
+// Anti-Grain Geometry - Version 2.3
+// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
+//
+// Permission to copy, use, modify, sell and distribute this software
+// is granted provided this copyright notice appears in all copies.
+// This software is provided "as is" without express or implied
+// warranty, and with no claim as to its suitability for any purpose.
+//
+//----------------------------------------------------------------------------
+// Contact: mcseem@antigrain.com
+// mcseemagg@yahoo.com
+// http://www.antigrain.com
+//----------------------------------------------------------------------------
+
+#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
+
+
+