require 'ruby-graphviz'

# Create a new graph
g = GraphViz.new( :G, :type => :digraph )

# Create two nodes
hello = g.add_nodes( "Hello" )
world = g.add_nodes( "World" )

# Create an edge between the two nodes
g.add_edges( hello, world )

# Generate output image
g.output( :png => "hello_world.png" )

require 'ruby-graphviz'

GraphViz::new( :G, :type => :digraph ) { |g|
  g.world( :label => "World" ) << g.hello( :label => "Hello" )
}.output( :png => "hello_world.png" )

    require 'ruby-graphviz/dsl'
    digraph :G do
      world[:label => "World"] << hello[:label => "Hello"]

      output :png => "hello_world.png"
    end

    require 'ruby-graphviz'

    # In this example, hello.dot is :
    #   digraph G {Hello->World;}

    GraphViz.parse( "hello.dot", :path => "/usr/local/bin" ) { |g|
      g.get_node("Hello") { |n|
        n[:label] = "Bonjour"
      }
      g.get_node("World") { |n|
        n[:label] = "Le Monde"
      }
    }.output(:png => "sample.png")

    require 'ruby-graphviz/graphml'

    g = GraphViz::GraphML.new( "graphml/cluster.graphml" )
    g.graph.output( :path => "/usr/local/bin", :png => "#{$0}.png" )

ruby2gv -Tpng -oruby2gv.png ruby2gv

gem2gv -Tpng -oruby-graphviz.png ruby-graphviz

$ cat hello.dot
digraph G {Hello->World;}

$ dot2ruby hello.dot
# This code was generated by dot2ruby.g

require 'rubygems'
require 'ruby-graphviz'
graph_g = GraphViz.digraph( "G" ) { |graph_g|
  graph_g[:bb] = '0,0,70,108'
  node_hello = graph_g.add_nodes( "Hello", :height => '0.5', :label => '\N', :pos => '35,90', :width => '0.88889' )
  graph_g.add_edges( "Hello", "World", :pos => 'e,35,36.413 35,71.831 35,64.131 35,54.974 35,46.417' )
  node_world = graph_g.add_nodes( "World", :height => '0.5', :label => '\N', :pos => '35,18', :width => '0.97222' )
}
puts graph_g.output( :canon => String )

require 'ruby-graphviz'
require 'ruby-graphviz/theory'

g = GraphViz.new( :G ) { ... }

t = GraphViz::Theory.new( g )

puts "Adjancy matrix : "
puts t.adjancy_matrix

puts "Symmetric ? #{t.symmetric?}"

puts "Incidence matrix :"
puts t.incidence_matrix

g.each_node do |name, node|
  puts "Degree of node `#{name}' = #{t.degree(node)}"
end

puts "Laplacian matrix :"
puts t.laplacian_matrix

puts "Dijkstra between a and f"
r = t.moore_dijkstra(g.a, g.f)
if r.nil?
  puts "No way !"
else
  print "\tPath : "; p r[:path]
  puts "\tDistance : #{r[:distance]}"
end

print "Ranges : "
rr = t.range
p rr
puts "Your graph contains circuits" if rr.include?(nil)

puts "Critical path : "
rrr = t.critical_path
print "\tPath "; p rrr[:path]
puts "\tDistance : #{rrr[:distance]}"