diff --git a/include/mapnik/raster.hpp b/include/mapnik/raster.hpp
index 2a9951966..5a5c7c59a 100644
--- a/include/mapnik/raster.hpp
+++ b/include/mapnik/raster.hpp
@@ -33,11 +33,17 @@ struct raster
     box2d<double> ext_;
     image_data_32 data_;
     bool premultiplied_alpha_;
+    raster(box2d<double> const& ext, unsigned width, unsigned height, bool premultiplied_alpha = false)
+        : ext_(ext),
+          data_(width,height),
+          premultiplied_alpha_(premultiplied_alpha)
+    {}
     raster(box2d<double> const& ext,image_data_32 const& data, bool premultiplied_alpha = false)
         : ext_(ext),
           data_(data),
           premultiplied_alpha_(premultiplied_alpha)
     {}
+
 };
 }