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 /*****************************************************************************/ // Copyright 2006 Adobe Systems Incorporated // All Rights Reserved. // // NOTICE: Adobe permits you to use, modify, and distribute this file in // accordance with the terms of the Adobe license agreement accompanying it. /*****************************************************************************/ /* \$Id: //mondo/dng_sdk_1_4/dng_sdk/source/dng_1d_function.h#1 \$ */ /* \$DateTime: 2012/05/30 13:28:51 \$ */ /* \$Change: 832332 \$ */ /* \$Author: tknoll \$ */ /** \file * Classes for a 1D floating-point to floating-point function abstraction. */ /*****************************************************************************/ #ifndef __dng_1d_function__ #define __dng_1d_function__ /*****************************************************************************/ #include "dng_classes.h" #include "dng_types.h" /*****************************************************************************/ /// \brief A 1D floating-point function. /// /// The domain (input) is always from 0.0 to 1.0, while the range (output) can be an arbitrary interval. class dng_1d_function { public: virtual ~dng_1d_function (); /// Returns true if this function is the map x -> y such that x == y for all x . That is if Evaluate(x) == x for all x. virtual bool IsIdentity () const; /// Return the mapping for value x. /// This method must be implemented by a derived class of dng_1d_function and the derived class determines the /// lookup method and function used. /// \param x A value between 0.0 and 1.0 (inclusive). /// \retval Mapped value for x virtual real64 Evaluate (real64 x) const = 0; /// Return the reverse mapped value for y. /// This method can be implemented by derived classes. The default implementation uses Newton's method to solve /// for x such that Evaluate(x) == y. /// \param y A value to reverse map. Should be within the range of the function implemented by this dng_1d_function . /// \retval A value x such that Evaluate(x) == y (to very close approximation). virtual real64 EvaluateInverse (real64 y) const; }; /*****************************************************************************/ /// An identity (x -> y such that x == y for all x) mapping function. class dng_1d_identity: public dng_1d_function { public: /// Always returns true for this class. virtual bool IsIdentity () const; /// Always returns x for this class. virtual real64 Evaluate (real64 x) const; /// Always returns y for this class. virtual real64 EvaluateInverse (real64 y) const; /// This class is a singleton, and is entirely threadsafe. Use this method to get an instance of the class. static const dng_1d_function & Get (); }; /*****************************************************************************/ /// A dng_1d_function that represents the composition (curry) of two other dng_1d_functions. class dng_1d_concatenate: public dng_1d_function { protected: const dng_1d_function &fFunction1; const dng_1d_function &fFunction2; public: /// Create a dng_1d_function which computes y = function2.Evaluate(function1.Evaluate(x)). /// Compose function1 and function2 to compute y = function2.Evaluate(function1.Evaluate(x)). The range of function1.Evaluate must be a subset of 0.0 to 1.0 inclusive, /// otherwise the result of function1(x) will be pinned (clipped) to 0.0 if <0.0 and to 1.0 if > 1.0 . /// \param function1 Inner function of composition. /// \param function2 Outer function of composition. dng_1d_concatenate (const dng_1d_function &function1, const dng_1d_function &function2); /// Only true if both function1 and function2 have IsIdentity equal to true. virtual bool IsIdentity () const; /// Return the composed mapping for value x. /// \param x A value between 0.0 and 1.0 (inclusive). /// \retval function2.Evaluate(function1.Evaluate(x)). virtual real64 Evaluate (real64 x) const; /// Return the reverse mapped value for y. /// Be careful using this method with compositions where the inner function does not have a range 0.0 to 1.0 . (Or better yet, do not use such functions.) /// \param y A value to reverse map. Should be within the range of function2.Evaluate. /// \retval A value x such that function2.Evaluate(function1.Evaluate(x)) == y (to very close approximation). virtual real64 EvaluateInverse (real64 y) const; }; /*****************************************************************************/ /// A dng_1d_function that represents the inverse of another dng_1d_function. class dng_1d_inverse: public dng_1d_function { protected: const dng_1d_function &fFunction; public: dng_1d_inverse (const dng_1d_function &f); virtual bool IsIdentity () const; virtual real64 Evaluate (real64 x) const; virtual real64 EvaluateInverse (real64 y) const; }; /*****************************************************************************/ #endif /*****************************************************************************/