Class: LemonGraph::Graphviz

Inherits:
Object
  • Object
show all
Defined in:
lib/lemongraph/graphviz.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(graph, **maps) ⇒ Graphviz

Returns a new LemonGraph::Graphviz object build from graph graph.

Keyword arguments can be provided.

  • keyword arguments starting with node_ are expected to be NodeMaps and will be applied to nodes
  • keyword arguments starting with edge_ are expected to be EdgeMaps and will be applied to edges
  • keyword arguments starting with arc_ are expected to be ArcMaps and will be applied to arcs

Other options can be provided as hashes or other objects.

Examples:

d = LemonGraph::Digraph.new
n = 7.times.collect{d.add_node}
n[0].arc_to n[1]
n[1].arc_to n[2]
n[1].arc_to n[3]
n[4].arc_from n[0]
n[5].arc_from n[4]
n[4].arc_to n[6]

nl = LemonGraph::NodeMap.new(d){|n| n.nb_outarcs > 0 ? n.id.to_s : "Leaf #{n.id}" }
nl[n[0]] = "Root 0"

nc = LemonGraph::NodeMap.new(d){|n| n.nb_outarcs > 0 ? :blue : :red }

al = LemonGraph::ArcMap.new(d){|a| "#{a.source.id} - #{a.target.id}"}

gv = LemonGraph::Graphviz.new(d
  node_label: nl,
  node_color: nc,
  arc_label: al,
  rankdir: 'LR',
  graph: {bgcolor: '#00FF00FF'},
  node: {fontname: 'DejaVu Sans', style: :filled, width: 0.4},
  edge: {penwidth: 0.75, arrowhead: :open}
)

puts gv.str
#=>
# digraph {
#   rankdir="LR";
#   graph [bgcolor="#00FF00FF"];
#   node [fontname="DejaVu Sans",style=filled,width=0.4];
#   edge [penwidth=0.75,arrowhead=open];
#   6 [label="Leaf 6",color=red];
#   5 [label="Leaf 5",color=red];
#   4 [label="4",color=blue];
#   3 [label="Leaf 3",color=red];
#   2 [label="Leaf 2",color=red];
#   1 [label="1",color=blue];
#   0 [label="Root 0",color=blue];
#   4 -> 6 [label="4 - 6"];
#   4 -> 5 [label="4 - 5"];
#   1 -> 3 [label="1 - 3"];
#   1 -> 2 [label="1 - 2"];
#   0 -> 4 [label="0 - 4"];
#   0 -> 1 [label="0 - 1"];
# }

Parameters:

Raises:

  • (TypeError) 


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# File 'lib/lemongraph/graphviz.rb', line 86

def initialize(graph, **maps)
  raise TypeError.new("Expecting a #{Graph} or a #{Digraph}, not a #{graph.class}") unless graph.is_a?(Graph) or graph.is_a?(Digraph)
  @str = ''
  node_maps = {}
  arc_maps = {}
  edge_maps = {}
  options = {}
  maps.each do |map_name, map|
    m = map_name.to_s.match(/^(node|arc|edge)_(.+?)s?$/)
    if m then
      case m[1]
      when 'node'
        raise "expecting a #{NodeMap} for :node_*, not a #{map.class}" unless NodeMap === map
        node_maps[m[2].to_sym] = map
      when 'edge'
        raise "expecting a #{EdgeMap} for :edge_*, not a #{map.class}" unless EdgeMap === map
        edge_maps[m[2].to_sym] = map
      when 'arc'
        raise "expecting a #{ArcMap} for :arc_*, not a #{map.class}" unless ArcMap === map
        arc_maps[m[2].to_sym] = map
      end
    else
      #raise 'expecting a Hash for options' unless Hash === map
      options[map_name] = map
    end
  end
  if graph.is_a?(Digraph) then
    @str << "digraph {\n"
  else
    @str << "graph {\n"
  end
  options.each do |k, h|
    if Hash === h then
      @str << "  #{k} [#{h.collect{|k, v| "#{k}=#{String === v ? "\"#{v}\"" : v}"}.join(',')}];\n"
    else
      @str << "  #{k}=#{String === h ? "\"#{h}\"" : h};\n"
    end
  end
  unless node_maps.empty? then
    graph.each_node do |n|
      params = node_maps.collect { |map_name, map|
        v = map[n]
        next nil if v.nil?
        if v.is_a?(String) then
          "#{map_name}=\"#{v}\""
        else
          "#{map_name}=#{v}"
        end
      }.compact.join(',')
      @str << "  #{n.id} [#{params}];\n" unless params.empty?
    end
  end
  if graph.is_a?(Digraph) then
    graph.each_arc do |a|
      @str << "  #{a.source.id} -> #{a.target.id}"
      params = arc_maps.collect { |map_name, map|
        v = map[a]
        next nil if v.nil?
        if v.is_a?(String) then
          "#{map_name}=\"#{v}\""
        else
          "#{map_name}=#{v}"
        end
      }.compact.join(',')
      @str << "#{params.empty? ? '' : " [#{params}]"};\n"
    end
  else
    graph.each_edge do |e|
      @str << "  #{e.u.id} -- #{e.v.id}"
      params = edge_maps.collect { |map_name, map|
        v = map[e]
        next nil if v.nil?
        if v.is_a?(String) then
          "#{map_name}=\"#{v}\""
        else
          "#{map_name}=#{v}"
        end
      }.compact.join(',')
      @str << "#{params.empty? ? '' : " [#{params}]"};\n"
    end
  end
  @str << "}\n"
end

Instance Attribute Details

#str ⇒ String (readonly)

Returns A graphviz representation of the graph this instance was build with.

Returns:

  • (String) —

    A graphviz representation of the graph this instance was build with



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# File 'lib/lemongraph/graphviz.rb', line 24

def str
  @str
end

Instance Method Details

#to_image(type) ⇒ String

Returns the binary content of the image.

Parameters:

  • type (Symbol) —

    :svg, :png or pdf

Returns:

  • (String) —

    the binary content of the image



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# File 'lib/lemongraph/graphviz.rb', line 191

def to_image(type)
  input = @str #.force_encoding('ASCII-8BIT')
  output = ''
#      output.force_encoding('ASCII-8BIT') if type == :png
  exit_status = nil
  Open3.popen3("dot #{type == :png ? '-Gdpi=90' : ''} -T#{type}") do |stdin, stdout, stderr, wait_thr|
    loop do
      unless input.empty? then
        n = stdin.write(input)
        input = input[n..-1]
        stdin.close if input.empty?
      end
      output += stdout.read
      begin
        while not(stderr.closed?) and (r = stderr.read_nonblock(8192)).length > 0 do
          $stderr.write r
        end
      rescue EOFError; end
      break if input.empty?
    end
    exit_status = wait_thr.value
  end
  raise "dot program exited with value #{exit_status.exitstatus}" unless exit_status.success?
  output.force_encoding('ASCII-8BIT')
  output
end

#to_svg ⇒ String

Returns an image as a SVG string.

Returns:

  • (String) —

    an image as a SVG string



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# File 'lib/lemongraph/graphviz.rb', line 172

def to_svg
  to_image(:svg)
end