Add scale operation for regions

region.cpp

@@ -67,6 +67,17 @@ region<T>::diameter (void) const {
 }
 
 
+template <typename T>
+void
+region<T>::scale (double factor) {
+    x -= (w * factor - w) / 2.0;
+    y -= (h * factor - h) / 2.0;
+
+    w *= factor;
+    h *= factor;
+}
+
+
 template <typename T>
 bool 
 region<T>::empty (void) const

region.hpp

@@ -46,6 +46,7 @@ namespace util {
 
         size_type area     (void) const;
         size_type diameter (void) const;
+        void scale (double factor);
 
         bool empty (void) const;