diff --git a/Makefile.am b/Makefile.am
index 62c87679..c39558f3 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -15,6 +15,7 @@ UTIL_INCLUDE =  	\
     enable_if.hpp  	\
     endian.hpp		\
     except.hpp  	\
+    extent.hpp		\
     fixed.hpp		\
     float.hpp		\
     fwd.hpp		\
@@ -46,6 +47,7 @@ UTIL_FILES   =		\
     debug.cpp   	\
     endian.cpp		\
     except.cpp  	\
+    extent.cpp		\
     fixed.cpp		\
     float.cpp		\
     guid.cpp		\
diff --git a/extent.cpp b/extent.cpp
new file mode 100644
index 00000000..fe984b5a
--- /dev/null
+++ b/extent.cpp
@@ -0,0 +1,79 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2010 Danny Robson <danny@blubinc.net>
+ */
+
+#include "extent.hpp"
+
+#include "debug.hpp"
+#include "maths.hpp"
+
+#include <cmath>
+
+using namespace util;
+
+
+template <typename T>
+extent<T>::extent (const T  _width, const T  _height):
+        width (_width),
+        height (_height)
+    { ; }
+
+
+template <typename T>
+T
+extent<T>::diameter (void) const {
+    return (T)sqrt (width * width + height * height);
+}
+
+
+template <typename T>
+T
+extent<T>::area (void) const
+    { return width * height; }
+
+
+template <typename T>
+bool
+extent<T>::empty (void) const
+    { return almost_equal (area(), 0); }
+
+
+template <typename T>
+bool
+extent<T>::operator ==(const extent& rhs) const {
+    return almost_equal (width,  rhs.width) &&
+           almost_equal (height, rhs.height);
+}
+
+
+template <typename T>
+void
+extent<T>::sanity (void) const
+    { check (width >= 0 && height >= 0); }
+
+
+namespace util {
+    template <>
+    void
+    extent<unsigned int>::sanity (void) const
+        { return; }
+}
+
+template struct extent<unsigned int>;
+template struct extent<double>;
+
diff --git a/extent.hpp b/extent.hpp
new file mode 100644
index 00000000..fa560697
--- /dev/null
+++ b/extent.hpp
@@ -0,0 +1,47 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2010 Danny Robson <danny@blubinc.net>
+ */
+
+#ifndef __UTIL_EXTENT_HPP
+#define __UTIL_EXTENT_HPP
+
+namespace util {
+    /**
+     * A pure two-dimensional size, without positioning
+     */
+    template <typename T>
+    struct extent {
+        T width, height;
+
+        extent (const T  _width, const T  _height);
+
+        T    area  (void) const;
+        T diameter (void) const;
+
+        bool empty (void) const;
+
+        bool operator ==(const extent& rhs) const;
+        bool operator !=(const extent& rhs) const
+            { return !(*this == rhs); }
+
+        void sanity (void) const;
+    };
+}
+
+#endif
+
diff --git a/region.cpp b/region.cpp
index d305dea2..a8c81895 100644
--- a/region.cpp
+++ b/region.cpp
@@ -28,62 +28,6 @@
 
 using namespace util;
 
-/*
- * Rect
- */
-template <typename T>
-extent<T>::extent (const T  _width, const T  _height):
-        width (_width),
-        height (_height)
-    { ; }
-
-
-template <typename T>
-T
-extent<T>::diameter (void) const {
-    return (T)sqrt (width * width + height * height);
-}
-
-
-template <typename T>
-T
-extent<T>::area (void) const
-    { return width * height; }
-
-
-template <typename T>
-bool
-extent<T>::empty (void) const
-    { return almost_equal (area(), 0); }
-
-
-template <typename T>
-bool
-extent<T>::operator ==(const extent& rhs) const {
-    return almost_equal (width,  rhs.width) &&
-           almost_equal (height, rhs.height);
-}
-
-
-template <typename T>
-void
-extent<T>::sanity (void) const
-    { check (width >= 0 && height >= 0); }
-
-
-namespace util {
-    template <>
-    void
-    extent<unsigned int>::sanity (void) const
-        { return; }
-}
-
-template struct extent<unsigned int>;
-template struct extent<double>;
-
-/*
- * Region
- */
 
 template <typename T>
 region<T>::region (T _x, T _y, T _width, T _height):
diff --git a/region.hpp b/region.hpp
index a8e6f46a..7da7e687 100644
--- a/region.hpp
+++ b/region.hpp
@@ -24,28 +24,6 @@
 #include "point.hpp"
 
 namespace util {
-    /**
-     * A pure two-dimensional size, without positioning
-     */
-    template <typename T>
-    struct extent {
-        T width, height;
-
-        extent (const T  _width, const T  _height);
-
-        T    area  (void) const;
-        T diameter (void) const;
-
-        bool empty (void) const;
-
-        bool operator ==(const extent& rhs) const;
-        bool operator !=(const extent& rhs) const
-            { return !(*this == rhs); }
-
-        void sanity (void) const;
-    };
-
-
     /**
      * A two-dimensional rectangle, with size and position.
      */