diff --git a/src/Canvas.cc b/src/Canvas.cc
index 1d2bc8b..8fafc63 100644
--- a/src/Canvas.cc
+++ b/src/Canvas.cc
@@ -6,6 +6,7 @@
 //
 
 #include "Canvas.h"
+#include "closure.h"
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
@@ -22,19 +23,6 @@
 #define BUFFER_DATA(buf) buf->data()
 #endif
 
-/*
- * PNG stream closure.
- */
-
-typedef struct {
-  Persistent<Function> pfn;
-  Handle<Function> fn;
-  unsigned len;
-  uint8_t *data;
-  Canvas *canvas;
-  cairo_status_t status;
-} closure_t;
-
 /*
  * Initialize Canvas.
  */
diff --git a/src/closure.h b/src/closure.h
new file mode 100644
index 0000000..2504771
--- /dev/null
+++ b/src/closure.h
@@ -0,0 +1,24 @@
+
+//
+// closure.h
+//
+// Copyright (c) 2010 LearnBoost <tj@learnboost.com>
+//
+
+#ifndef __NODE_CLOSURE_H__
+#define __NODE_CLOSURE_H__
+
+/*
+ * PNG stream closure.
+ */
+
+typedef struct {
+  Persistent<Function> pfn;
+  Handle<Function> fn;
+  unsigned len;
+  uint8_t *data;
+  Canvas *canvas;
+  cairo_status_t status;
+} closure_t;
+
+#endif /* __NODE_CLOSURE_H__ */