@@ -1146,6 +1146,8 @@ class DotParser(Parser):

 class XDotParser(DotParser):

+    XDOTVERSION = '1.6'

+

     def __init__(self, xdotcode):

         lexer = DotLexer(buf = xdotcode)

         DotParser.__init__(self, lexer)

@@ -1158,26 +1160,34 @@ class XDotParser(DotParser):

     def handle_graph(self, attrs):

         if self.top_graph:

+            # Check xdot version

             try:

-                bb = attrs['bb']

+                xdotversion = attrs['xdotversion']

             except KeyError:

-                return

+                pass

+            else:

+                if float(xdotversion) > float(self.XDOTVERSION):

+                    sys.stderr.write('warning: xdot version %s, but supported is %s\n' % (xdotversion, self.XDOTVERSION))

-            if not bb:

+            # Parse bounding box

+            try:

+                bb = attrs['bb']

+            except KeyError:

                 return

-            xmin, ymin, xmax, ymax = map(float, bb.split(","))

+            if bb:

+                xmin, ymin, xmax, ymax = map(float, bb.split(","))

-            self.xoffset = -xmin

-            self.yoffset = -ymax

-            self.xscale = 1.0

-            self.yscale = -1.0

-            # FIXME: scale from points to pixels

+                self.xoffset = -xmin

+                self.yoffset = -ymax

+                self.xscale = 1.0

+                self.yscale = -1.0

+                # FIXME: scale from points to pixels

-            self.width  = max(xmax - xmin, 1)

-            self.height = max(ymax - ymin, 1)

+                self.width  = max(xmax - xmin, 1)

+                self.height = max(ymax - ymin, 1)

-            self.top_graph = False

+                self.top_graph = False

         for attr in ("_draw_", "_ldraw_", "_hdraw_", "_tdraw_", "_hldraw_", "_tldraw_"):

             if attr in attrs: