public void WriteStartGraph(string name, GraphOptions options) { if (name == null) { throw new ArgumentNullException(name); } this.checkstate(State.Begin); this.writeline("digraph {0}", name); this.writeline("{{"); this.writeline(""); if (options != null) { if (options.Overlap.HasValue) { this.writeline("\toverlap=\"{0}\"",options.Overlap.Value.ToString().ToLower()); } } this.state = State.Graph; }