--- a/contenttransformer/transformers.py	Thu Jan 14 00:09:06 2010 -0500
+++ b/contenttransformer/transformers.py	Thu Jan 14 00:16:34 2010 -0500
@@ -5,11 +5,14 @@
 class Graphviz(object):
     def __init__(self, content):
         """create a Graphviz object"""
-        raise NotImplementedError # TODO
+        process = subprocess.Popen(['dot', '-Tpng'],
+                                   stdin=subprocess.PIPE,
+                                   stdout=subprocess.PIPE)
+        self.image, _ = process.communicate(content)
 
     def __call__(self, environ, start_response):
         """return a WSGI response"""
-   
+        return Response(content_type='image/png', body=self.image)(environ, start_response)   
 
 class RestructuredText(object):
     settings = { 'report_level': 5 }