Gave point_transform_affine member functions so the user can find

out what the transformation matrix is.

dlib/geometry/point_transforms.h

@@ -93,6 +93,12 @@ namespace dlib
             return m*p + b;
         }
 
+        const matrix<double,2,2>& get_m(
+        ) const { return m; }
+
+        const dlib::vector<double,2>& get_b(
+        ) const { return b; }
+
     private:
         matrix<double,2,2> m;
         dlib::vector<double,2> b;

dlib/geometry/point_transforms_abstract.h

@@ -26,6 +26,8 @@ namespace dlib
         );
         /*!
             ensures
+                - #get_m() == m
+                - #get_b() == b
                 - When (*this)(p) is invoked it will return a point P such that:
                     - P == m*p + b
         !*/
@@ -39,6 +41,20 @@ namespace dlib
                   to p and returns the result.
         !*/
 
+        const matrix<double,2,2>& get_m(
+        ) const;
+        /*!
+            ensures
+                - returns the transformation matrix used by this object.
+        !*/
+
+        const dlib::vector<double,2>& get_b(
+        ) const;
+        /*!
+            ensures
+                - returns the offset vector used by this object.
+        !*/
+
     };
 
 // ----------------------------------------------------------------------------------------