GvizでGraphvizのノードの形とかエッジの形とか使える色の名前とかの属性情報をゲットするよ！

% gviz -m man
--man(-m) accepts any of them:
  graph, node, edge, subgraph, cluster,
  arrows, shapes, output_formats
  color_names, color_schemes,
  full_color_names, full_color_schem

--------------------
% gviz -m color_names
Color names:
  aliceblue, antiquewhite, aquamarine, azure, beige, bisque, black, blanchedalmond
  blueviolet, brown, burlywood, cadetblue, chartreuse, chocolate, coral
  cornsilk, crimson, cyan, darkgoldenrod, darkgreen, darkkhaki, darkolivegreen
  darkorchid, darksalmon, darkseagreen, darkslateblue, darkslategray
  darkturquoise, darkviolet, deeppink, deepskyblue, dimgray, dimgrey, dodgerblue
  floralwhite, forestgreen, gainsboro, ghostwhite, gold, goldenrod, gray, green
  grey, honeydew, hotpink, indianred, indigo, invis, ivory, khaki, lavender
  lawngreen, lemonchiffon, lightblue, lightcoral, lightcyan, lightgoldenrod
  lightgray, lightgrey, lightpink, lightsalmon, lightseagreen, lightskyblue
  lightslategray, lightslategrey, lightsteelblue, lightyellow, limegreen, linen
  maroon, mediumaquamarine, mediumblue, mediumorchid, mediumpurple
  mediumslateblue, mediumspringgreen, mediumturquoise, mediumvioletred
  mintcream, mistyrose, moccasin, navajowhite, navy, navyblue, none, oldlace, olivedrab
  orangered, orchid, palegoldenrod, palegreen, paleturquoise, palevioletred
  peachpuff, peru, pink, plum, powderblue, purple, red, rosybrown, royalblue, saddlebrown
  sandybrown, seagreen, seashell, sienna, skyblue, slateblue, slategray, slategrey
  springgreen, steelblue, tan, thistle, tomato, transparent, turquoise, violet

--------------------
% gviz -m shapes     
Shapes:
  box, polygon, ellipse, oval, circle, point, egg, triangle, plaintext, diamond, trapezium
  house, pentagon, hexagon, septagon, octagon, doublecircle, doubleoctagon
  invtriangle, invtrapezium, invhouse, Mdiamond, Msquare, Mcircle, rect, rectangle
  none, note, tab, folder, box3d, component, promoter, cds, terminator, utr, primersite
  fivepoverhang, threepoverhang, noverhang, assembly, signature, insulator

--------------------
% gviz -m arrows
Arrows:
  box, lbox, rbox, obox, olbox, orbox, crow, lcrow, rcrow, diamond, ldiamond, rdiamond
  oldiamond, ordiamond, dot, odot, inv, linv, rinv, oinv, olinv, orinv, none, normal, lnormal

--------------------
% gviz -m node
Node attributes (type|default|minimum|notes):
  URL (escString | <none> |  | svg, postscript, map only)
  area (double | 1.0 | >0 | patchwork only)
  color (color/colorList | black |  | )
  colorscheme (string |  |  | )
  comment (string |  |  | )
  distortion (double | 0.0 | -100.0 | )
  fillcolor (color/colorList | lightgrey(nodes)black(clusters) |  | )
  fixedsize (bool | false |  | )
  fontcolor (color | black |  | )
  fontname (string | Times-Roman |  | )
  fontsize (double | 14.0 | 1.0 | )  gradientangle (int |  |  | )
  group (string |  |  | dot only)
  height (double | 0.5 | 0.02 | )
  href (escString |  |  | svg, postscript, map only)
  id (escString |  |  | svg, postscript, map only)
      ------- 中略 -------
  shape (shape | ellipse |  | )
  shapefile (string |  |  | )
  showboxes (int | 0 | 0 | dot only)
  sides (int | 4 | 0 | )
  skew (double | 0.0 | -100.0 | )
  sortv (int | 0 | 0 | )
  style (style |  |  | )
  target (escString/string | <none> |  | svg, map only)
  tooltip (escString |  |  | svg, cmap only)
  vertices (pointList |  |  | write only)
  width (double | 0.75 | 0.01 | )
  xlabel (lblString |  |  | )
  z (double | 0.0 | -MAXFLOAT-1000 | )

require 'gviz'

Gviz.ATTR :edge => [["URL", ["escString", "<none>", nil, "svg, postscript, map only"]], ["arrowhead", ["arrowType", "normal", nil, nil]], ["arrowsize", ["double", "1.0", "0.0", nil]], ["arrowtail", ["arrowType", "normal", nil, nil]], ["color", ["color/colorList", "black", nil, nil]], ["colorscheme", ["string", nil, nil, nil]], ["comment", ["string", nil, nil, nil]], ["constraint", ["bool", "true", nil, "dot only"]],  --- 中略 ---  ["tailtooltip", ["escString", nil, nil, "svg, cmap only"]], ["target", ["escString/string", "<none>", nil, "svg, map only"]], ["tooltip", ["escString", nil, nil, "svg, cmap only"]], ["weight", ["intdouble", "1", "0(dot)1(neato,fdp)", nil]], ["xlabel", ["lblString", nil, nil, nil]]]

#graph.ru
global layout:'neato'
nodes style:'filled'

COLOR_NAMES.each do |c|
  fc = DARK_COLORS.include?(c) ? 'white' : 'black'
  node c.intern, label:c, fillcolor:c, color:c, fontcolor:fc
end

save :attributes

% gviz
% open attributes.dot

global layout:'neato'
nodes style:'filled'

+ shapes = SHAPES.cycle

COLOR_NAMES.each do |c|
  fc = DARK_COLORS.include?(c) ? 'white' : 'black'
+  s = shapes.next
+  node c.intern, label:"#{c}\n#{s}", fillcolor:c, color:c, fontcolor:fc,
+                 shape:s
end

save :attributes, :png

+ global layout:'neato', overlap:false, size:16
nodes style:'filled'

shapes = SHAPES.cycle

COLOR_NAMES.each do |c|
  fc = DARK_COLORS.include?(c) ? 'white' : 'black'
  s = shapes.next
  node c.intern, label:"#{c}\n#{s}", fillcolor:c, color:c, fontcolor:fc,
                 shape:s
end

+ arrows = ARROWS.cycle
+ 
+ COLOR_NAMES.shuffle.each_slice(7) do |sun, *astros|
+   arr = arrows.next
+   route sun => astros
+   edge "#{sun}_*", arrowhead:arr, label:arr
+ end

save :attributes, :png