Check xdotversion attribute.

And warn about unsupported versions.

xdot.py

@@ -1146,6 +1146,8 @@ def handle_edge(self, src_id, dst_id, attrs):
 
 class XDotParser(DotParser):
 
+ XDOTVERSION = '1.6'
+
  def __init__(self, xdotcode):
  lexer = DotLexer(buf = xdotcode)
  DotParser.__init__(self, lexer)
@@ -1158,26 +1160,34 @@ def __init__(self, xdotcode):
 
  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: