Added global function versions of rectangle::intersect() and rectangle::area()

to make the overall rectangle API more uniform.

dlib/geometry/rectangle.h

@@ -361,6 +361,19 @@ namespace dlib
         return result;
     }
 
+// ----------------------------------------------------------------------------------------
+
+    inline rectangle intersect (
+        const rectangle& a,
+        const rectangle& b
+    ) { return a.intersect(b); }
+
+// ----------------------------------------------------------------------------------------
+
+    inline unsigned long area (
+        const rectangle& a
+    ) { return a.area(); }
+
 // ----------------------------------------------------------------------------------------
 
     inline point center (

dlib/geometry/rectangle_abstract.h

@@ -477,6 +477,28 @@ namespace dlib
               and height)
     !*/
 
+// ----------------------------------------------------------------------------------------
+
+    inline rectangle intersect (
+        const rectangle& a,
+        const rectangle& b
+    );
+    /*!
+        ensures
+            - returns a.intersect(b)
+              (i.e. returns a rectangle representing the intersection of a and b)
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    inline unsigned long area (
+        const rectangle& a
+    );
+    /*!
+        ensures
+            - returns a.area()
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
     inline const rectangle shrink_rect (