class RdfToGraphviz

@note The most advance example is show in scenrio 3. The most advance example is shown in scenario 3. The different gem (project) will address the question: how automatically generate graphviz attr file by rules. @example scenario 1: Generates Graphviz graph from rdf_graph and save to png files (default files name: “res_graph.png”)

require 'rdf_to_graphviz'
konwerter = RdfToGraphviz.new
queryable = RDF::Graph.load("http://ruby-rdf.github.com/rdf/etc/doap.nt")  
konwerter.save_rdf_graph_as(queryable, :is_literal_object_uniq => false) # literal objcects aren't unig

@example scenario 2: Generates dot string from rdf_graph (default options). The same result like in 1 scenario.

require 'rdf_to_graphviz'
konwerter = RdfToGraphviz.new
queryable = RDF::Graph.load("http://ruby-rdf.github.com/rdf/etc/doap.nt")  
str = konwerter.rdf_graph_to_dot(queryable)
GraphViz.parse_string(str).output( :png => "res_graph.png" )

@example scenario 3: Generate Graphviz graph from rdf graph and save to png files using attributes defining in another rdf file

require 'rdf_to_graphviz'
konwerter = RdfToGraphviz.new
queryable = RDF::Graph.load("https://github.com/widu/rdf_to_graphviz/blob/master/ttl/test1.ttl") 
rdf_presentation_attr = = RDF::Graph.load("https://github.com/widu/rdf_to_graphviz/blob/master/ttl/grvz.ttl") # reads rdf which contain attr definitions from turtle file
options = {:presentation_attr => rdf_presentation_attr}
konwerter.save_rdf_graph_as(queryable, options)

Public Class Methods

new() click to toggle source

# File lib/rdf_to_graphviz.rb, line 33
def initialize
        
        @atr = {}
end

Public Instance Methods

rdf_graph_to_dot(rdf_graph, options = {}) click to toggle source

Generates string containing definition of graph in dot format from RDF::Graph @note This method should only be used in outer space. @param [RDF::Graph] rdf_graph

@param [Hash{Symbol => Object}] options @option options [TrueClass] :digraph (true)- if true, graph has a direction @option options [String] :subject_shape (“doublecircle”) @option options [String] :object_shape (“circle”) @option options [String] :literal_object_shape (“rectangle”) @option options [String] :subject_color (“red”) @option options [String] :object_color (“blue”) @option options [String] :predicate_color (“black”) @option options [TrueClass] :is_literal_object_uniq (true) @option options [RDF::Graph] :presentation_attr @return [String] - contain representation of RDF::Graph in Graphviz dot

# File lib/rdf_to_graphviz.rb, line 161
def rdf_graph_to_dot(rdf_graph, options = {})
        if options[:presentation_attr]
                build_atr(options[:presentation_attr])
        end
        build_graph(rdf_graph, options).to_s
end

save_rdf_graph_as(rdf_graph, options = {}) click to toggle source

Saves RDF::Graph as png file or different format

@param [RDF::Graph] rdf_graph

@param [Hash{Symbol => Object}] options @option options [TrueClass] :digraph (true)- if true, graph has a direction @option options [String] :subject_shape (“doublecircle”) @option options [String] :object_shape (“circle”) @option options [String] :literal_object_shape (“rectangle”) @option options [String] :subject_color (“red”) @option options [String] :object_color (“blue”) @option options [String] :predicate_color (“black”) @option options [TrueClass] :is_literal_object_uniq (true) @option options [RDF::Graph] :presentation_attr @option options [String] :format (:png) @option options [String] :file_name (“res_graph.png”) @return [nil]

# File lib/rdf_to_graphviz.rb, line 187
def save_rdf_graph_as(rdf_graph, options = {})
        options[:format] ||= :png
        options[:file_name] ||= "res_graph.png"
        if options[:presentation_attr]
                build_atr(options[:presentation_attr])
        end
        g = build_graph(rdf_graph, options)
        g.output( options[:format] => options[:file_name] )
end

Private Instance Methods

build_atr(rdf_graph) click to toggle source

# File lib/rdf_to_graphviz.rb, line 115
def build_atr(rdf_graph)
        
        atr_lok = {}
        rdf_graph.each_statement do |statement|
                p = statement[1].pname
                # puts p
                indx = p.index("grvz#")

                if indx
                  p1 = p[indx+5..-1].downcase
                
                  obj = term_name(statement[0])
                # puts obj
                # puts p
                  st= statement[2].to_s
                  atr_lok = @atr[obj]
                  if atr_lok == nil then
                        atr_lok = {p1 => st}
                  else
                        atr_lok[p1] = st
                  end
                #puts atr_lok
                  @atr[obj] = atr_lok        
                end
        end
        @atr
        
end

build_graph(rdf_graph, options = {}) click to toggle source

Build graph object from rdf_graph

@param  [RDF::Graph]             rdf_graph                
@param  [Hash{Symbol => Object}] options
@option options [TrueClass]  :digraph                  - default = true - if true, graph has a direction
@option options [String]     :subject_shape            - default = doublecircle
@option options [String]     :object_shape             - default = circle
@option options [String]     :literal_object_shape     - default = rectangle
@option options [String]     :subject_color            - default = red
@option options [String]     :object_color             - default = blue
@option options [String]     :predicate_color          - default = black
@option options [TrueClass]  :is_literal_object_uniq   - default = true
@return [String] - contain representation of RDF::Graph in Graphviz dot

# File lib/rdf_to_graphviz.rb, line 63
def build_graph(rdf_graph, options = {})
        options[:graph_type] ||= :digraph
        options[:subject_shape] ||= "doublecircle"
        options[:object_shape] ||= "circle"
        options[:literal_object_shape] ||= "rectangle"
        options[:subject_color] ||= "red"
        options[:object_color] ||= "blue"
        options[:predicate_color] ||= "black"
        options[:is_literal_object_uniq] = true if options[:is_literal_object_uniq].nil?
        nodes = []
        n=0
        graph = GraphViz.new( :G, :type => options[:graph_type] )
        rdf_graph.each_statement do |statement|
                if @atr[term_name(statement[0])]
                        s = graph.add_nodes( term_name(statement[0]), @atr[term_name(statement[0])])
                else
                        s = graph.add_nodes( term_name(statement[0]), {:shape => options[:subject_shape], :color => options[:subject_color] })
                end
                nodes << term_name(statement[0])
                
                if statement[2].literal? then
                        if options[:is_literal_object_uniq] == true
                          o = graph.add_nodes( statement[2].to_s, {:shape => options[:literal_object_shape]})
                        else
                          o = graph.add_nodes( "o"+n.to_s, {:label => statement[2].to_s, :shape => options[:literal_object_shape]})
                          n += 1
                        end  
                else
                        if @atr[term_name(statement[2])]
                                o = graph.add_nodes( term_name(statement[2]), @atr[term_name(statement[2])])
                        else
                                o = graph.add_nodes( term_name(statement[2]), {:shape => options[:object_shape], :color => options[:object_color]}) 
                        end
                end        
                # Create an edge between the two nodes
                if @atr[statement[1].pname]
                        graph.add_edges( s, o, @atr[statement[1].pname] )
                else
                        graph.add_edges( s, o, {:label => statement[1].pname, :color => options[:predicate_color] } )
                end
        end
        nodes.each do |nd|
                if @atr[nd]
                        graph.add_nodes( nd, @atr[nd])
                else
                        graph.add_nodes( nd, {:shape => options[:subject_shape], :color => options[:subject_color] })
                end  
        end
        # graph.output( :png => "res_graph.png" )
        graph
end

term_name(statement) click to toggle source

# File lib/rdf_to_graphviz.rb, line 38
def term_name(statement)
        if statement.literal?
                statement.to_s
        elsif statement.node?
                statement.to_s
        else
                statement.pname
        end
                 
end