diff --git a/include/mapnik/css_color_grammar.hpp b/include/mapnik/css_color_grammar.hpp
index b54273c49..e969fa3fe 100644
--- a/include/mapnik/css_color_grammar.hpp
+++ b/include/mapnik/css_color_grammar.hpp
@@ -106,7 +106,19 @@ struct alpha_conv_impl
 };
 
 // http://www.w3.org/TR/css3-color/#hsl-color
-inline double hue_to_rgb( double m1, double m2, double h);
+inline double hue_to_rgb( double m1, double m2, double h)
+{
+    if (h < 0.0) h = h + 1.0;
+    else if (h > 1) h = h - 1.0;
+
+    if (h * 6 < 1.0)
+        return m1 + (m2 - m1) * h * 6.0;
+    if (h * 2 < 1.0)
+        return m2;
+    if (h * 3 < 2.0)
+        return m1 + (m2 - m1)* (2.0/3.0 - h) * 6.0;
+    return m1;
+}
 
 struct hsl_conv_impl
 {
@@ -396,22 +408,6 @@ struct alpha_conv_impl
     }
 };
 
-
-// http://www.w3.org/TR/css3-color/#hsl-color
-inline double hue_to_rgb( double m1, double m2, double h)
-{
-    if (h < 0.0) h = h + 1.0;
-    else if (h > 1) h = h - 1.0;
-
-    if (h * 6 < 1.0)
-        return m1 + (m2 - m1) * h * 6.0;
-    if (h * 2 < 1.0)
-        return m2;
-    if (h * 3 < 2.0)
-        return m1 + (m2 - m1)* (2.0/3.0 - h) * 6.0;
-    return m1;
-}
-
 struct hsl_conv_impl
 {
     template<typename T0,typename T1, typename T2, typename T3>
diff --git a/src/css_color_grammar.cpp b/src/css_color_grammar.cpp
index a31b3cf0c..948848df9 100644
--- a/src/css_color_grammar.cpp
+++ b/src/css_color_grammar.cpp
@@ -183,20 +183,6 @@ named_colors_::named_colors_()
         ;
 }
 
-double hue_to_rgb( double m1, double m2, double h)
-{
-    if (h < 0.0) h = h + 1.0;
-    else if (h > 1) h = h - 1.0;
-
-    if (h * 6 < 1.0)
-        return m1 + (m2 - m1) * h * 6.0;
-    if (h * 2 < 1.0)
-        return m2;
-    if (h * 3 < 2.0)
-        return m1 + (m2 - m1)* (2.0/3.0 - h) * 6.0;
-    return m1;
-}
-
 template struct mapnik::css_color_grammar<std::string::const_iterator>;
 
 }