Added member functions to point_rotator and point_transform to allow

a user to read the state of these objects.

dlib/geometry/point_transforms.h

@@ -37,6 +37,15 @@ namespace dlib
             return dlib::vector<double,2>(x,y);
         }
 
+        const matrix<double,2,2> get_m(
+        ) const 
+        { 
+            matrix<double,2,2> temp;
+            temp = cos_angle, -sin_angle,
+                   sin_angle, cos_angle;
+            return temp; 
+        }
+
     private:
         double sin_angle;
         double cos_angle;
@@ -68,6 +77,18 @@ namespace dlib
             return dlib::vector<double,2>(x,y) + translate;
         }
 
+        const matrix<double,2,2> get_m(
+        ) const 
+        { 
+            matrix<double,2,2> temp;
+            temp = cos_angle, -sin_angle,
+                   sin_angle, cos_angle;
+            return temp; 
+        }
+
+        const dlib::vector<double,2> get_b(
+        ) const { return translate; }
+
     private:
         double sin_angle;
         double cos_angle;

dlib/geometry/point_transforms_abstract.h

@@ -112,8 +112,24 @@ namespace dlib
         ) const;
         /*!
             ensures
-                - rotates p, then translates it and returns the result
+                - rotates p, then translates it and returns the result.  The output
+                  of this function is therefore equal to get_m()*p + get_b().
         !*/
+
+        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.
+        !*/
+
     };
 
 // ----------------------------------------------------------------------------------------
@@ -145,7 +161,15 @@ namespace dlib
         ) const;
         /*!
             ensures
-                - rotates p and returns the result
+                - rotates p and returns the result. The output of this function is
+                  therefore equal to get_m()*p.
+        !*/
+
+        const matrix<double,2,2> get_m(
+        ) const;
+        /*!
+            ensures
+                - returns the transformation matrix used by this object.
         !*/
     };
 

dlib/test/geometry.cpp

@@ -294,6 +294,8 @@ namespace
             point_rotator rot(pi/2);
             DLIB_TEST(rot(point(1,0)) == point(0,1));
             DLIB_TEST(rot(point(0,1)) == point(-1,0));
+            DLIB_TEST(point(rot.get_m()*(dlib::vector<double,2>(1,0))) == point(0,1));
+            DLIB_TEST(point(rot.get_m()*(dlib::vector<double,2>(0,1))) == point(-1,0));
         }
 
         {