1 /*! ======================================================================== 2 ** Extended Template and Library 3 ** Utility Curve Template Class Implementations 4 ** $Id$ 5 ** 6 ** Copyright (c) 2002 Robert B. Quattlebaum Jr. 7 ** 8 ** This package is free software; you can redistribute it and/or 9 ** modify it under the terms of the GNU General Public License as 10 ** published by the Free Software Foundation; either version 2 of 11 ** the License, or (at your option) any later version. 12 ** 13 ** This package is distributed in the hope that it will be useful, 14 ** but WITHOUT ANY WARRANTY; without even the implied warranty of 15 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 ** General Public License for more details. 17 ** 18 ** === N O T E S =========================================================== 19 ** 20 ** This is an internal header file, included by other ETL headers. 21 ** You should not attempt to use it directly. 22 ** 23 ** ========================================================================= */ 24 25 /* === S T A R T =========================================================== */ 26 27 #ifndef __ETL__CURVE_FUNC_H 28 #define __ETL__CURVE_FUNC_H 29 30 /* === H E A D E R S ======================================================= */ 31 32 #include <functional> 33 #include "_fixed.h" 34 35 /* -- C L A S S E S --------------------------------------------------------- */ 36 37 template <class T, class K=float> 38 struct affine_combo 39 { 40 // from (a) to (x) : x = a(1-t) + b(t) operatoraffine_combo41 T operator()(const T &a,const T &b,const K &t)const 42 { 43 return T( (b-a)*t+a ); 44 } 45 46 // from (x) to (a) : a = (x-b(t)) / (1-t) reverseaffine_combo47 T reverse(const T &x, const T &b, const K &t)const 48 { 49 return T( (x-t*b)*(static_cast<K>(1)/(static_cast<K>(1)-t)) ); 50 } 51 }; 52 53 template <class T, class K=float> 54 struct distance_func : public std::binary_function<T, T, K> 55 { operatordistance_func56 K operator()(const T &a,const T &b)const 57 { 58 T delta=b-a; 59 return static_cast<K>(delta*delta); 60 } 61 cookdistance_func62 K cook(const K &x)const { return x*x; } uncookdistance_func63 K uncook(const K &x)const { return sqrt(x); } 64 65 }; 66 67 /* -- E N D ----------------------------------------------------------------- */ 68 69 #endif 70