X-Git-Url: https://git.pterodactylus.net/?a=blobdiff_plain;f=ETL%2Ftrunk%2FETL%2F_curve_func.h;h=b2898aaf201fa772c5dd83febe3e14b77ec5e0bf;hb=b0d82d28d294043cd7bf90f89ac802bf2b2f71fe;hp=b1be012dd436f3d80624af07d42294629302aa99;hpb=117425a5858bb094f2e54af5d018499ab703b227;p=synfig.git

diff --git a/ETL/trunk/ETL/_curve_func.h b/ETL/trunk/ETL/_curve_func.h
index b1be012..b2898aa 100644
--- a/ETL/trunk/ETL/_curve_func.h
+++ b/ETL/trunk/ETL/_curve_func.h
@@ -1,7 +1,7 @@
 /*! ========================================================================
 ** Extended Template and Library
 ** Utility Curve Template Class Implementations
-** $Id: _curve_func.h,v 1.1.1.1 2005/01/04 01:31:47 darco Exp $
+** $Id$
 **
 ** Copyright (c) 2002 Robert B. Quattlebaum Jr.
 **
@@ -36,15 +36,17 @@
 template <class T, class K=float>
 struct affine_combo
 {
+	// from (a) to (x) : x = a(1-t) + b(t)
 	T operator()(const T &a,const T &b,const K &t)const
 	{
 		return T( (b-a)*t+a );
 	}
 
+	// from (x) to (a) : a = (x-b(t)) / (1-t)
 	T reverse(const T &x, const T &b, const K &t)const
 	{
 		return T( (x-t*b)*(static_cast<K>(1)/(static_cast<K>(1)-t)) );
-	}	
+	}
 };
 
 template <class T, class K=float>
@@ -55,10 +57,10 @@ struct distance_func : public std::binary_function<T, T, K>
 		T delta=b-a;
 		return static_cast<K>(delta*delta);
 	}
-	
+
 	K cook(const K &x)const { return x*x; }
 	K uncook(const K &x)const { return sqrt(x); }
-	
+
 };
 
 /* -- E N D ----------------------------------------------------------------- */