= Graphviz filter for AsciiDoc =

Author: Gouichi Iisaka

Version: 1.1.3

== Introduction ==

The Graphviz(link:http://www.graphviz.org[]) is a way of representing structural information
as diagrams of abstract graphs and networks.


Automatic graph drawing has many important applications
in software engineering, database and web design, networking,
and in visual interfaces for many other domains.

Graphviz take descriptions of graphs in a simple text language,
And has many useful features for concrete diagrams,
such as options for colors, fonts, tabular node layouts,
line styles, hyperlinks, and custom shapes.

AsciiDoc can external shell commands used to process Paragraph and 
DelimitedBlock content by Filter.

So now, AsciiDoc can draw graphs via graphviz filter.

== Examples ==

=== Simple ===
.....................................................................
[graphviz]
---------------------------------------------------------------------
digraph G { rankdir=LR; Graphviz->AsciiDoc->HTML}
---------------------------------------------------------------------
.....................................................................

[graphviz]
---------------------------------------------------------------------
digraph G { rankdir=LR; Graphviz->AsciiDoc->HTML}
---------------------------------------------------------------------

=== Using options ===
.....................................................................
["graphviz", "sample2.png"]
---------------------------------------------------------------------
digraph automata_0 {
  size ="8.5, 11";
  node [shape = circle];
  0 [ style = filled, color=lightgrey ];
  2 [ shape = doublecircle ];
  0 -> 2 [ label = "a " ];
  0 -> 1 [ label = "other " ];
  1 -> 2 [ label = "a " ];
  1 -> 1 [ label = "other " ];
  2 -> 2 [ label = "a " ];
  2 -> 1 [ label = "other " ];
  "Machine: a" [ shape = plaintext ];
} 
---------------------------------------------------------------------
.....................................................................

["graphviz", "sample2.png"]
---------------------------------------------------------------------
digraph automata_0 {
    size ="8.5, 11";
    node [shape = circle];
    0 [ style = filled, color=lightgrey ];
    2 [ shape = doublecircle ];
    0 -> 2 [ label = "a " ];
    0 -> 1 [ label = "other " ];
    1 -> 2 [ label = "a " ];
    1 -> 1 [ label = "other " ];
    2 -> 2 [ label = "a " ];
    2 -> 1 [ label = "other " ];
    "Machine: a" [ shape = plaintext ];
} 
---------------------------------------------------------------------

=== Using Layout ===

.....................................................................
["graphviz", "sample3.png", "dot"]
---------------------------------------------------------------------
digraph finite_state_machine {
  rankdir=LR;
  size="8,5"
  node [shape = doublecircle]; LR_0 LR_3 LR_4 LR_8;
  node [shape = circle];
  LR_0 -> LR_2 [ label = "SS(B)" ];
  LR_0 -> LR_1 [ label = "SS(S)" ];
  LR_1 -> LR_3 [ label = "S($end)" ];
  LR_2 -> LR_6 [ label = "SS(b)" ];
  LR_2 -> LR_5 [ label = "SS(a)" ];
  LR_2 -> LR_4 [ label = "S(A)" ];
  LR_5 -> LR_7 [ label = "S(b)" ];
  LR_5 -> LR_5 [ label = "S(a)" ];
  LR_6 -> LR_6 [ label = "S(b)" ];
  LR_6 -> LR_5 [ label = "S(a)" ];
  LR_7 -> LR_8 [ label = "S(b)" ];
  LR_7 -> LR_5 [ label = "S(a)" ];
  LR_8 -> LR_6 [ label = "S(b)" ];
  LR_8 -> LR_5 [ label = "S(a)" ];
}
---------------------------------------------------------------------
.....................................................................

["graphviz", "sample3.png", "dot"]
---------------------------------------------------------------------
digraph finite_state_machine {
    rankdir=LR;
    size="8,5"
    node [shape = doublecircle]; LR_0 LR_3 LR_4 LR_8;
    node [shape = circle];
    LR_0 -> LR_2 [ label = "SS(B)" ];
    LR_0 -> LR_1 [ label = "SS(S)" ];
    LR_1 -> LR_3 [ label = "S($end)" ];
    LR_2 -> LR_6 [ label = "SS(b)" ];
    LR_2 -> LR_5 [ label = "SS(a)" ];
    LR_2 -> LR_4 [ label = "S(A)" ];
    LR_5 -> LR_7 [ label = "S(b)" ];
    LR_5 -> LR_5 [ label = "S(a)" ];
    LR_6 -> LR_6 [ label = "S(b)" ];
    LR_6 -> LR_5 [ label = "S(a)" ];
    LR_7 -> LR_8 [ label = "S(b)" ];
    LR_7 -> LR_5 [ label = "S(a)" ];
    LR_8 -> LR_6 [ label = "S(b)" ];
    LR_8 -> LR_5 [ label = "S(a)" ];
 }
---------------------------------------------------------------------


== Layout ==

Layout for graphviz as follows.  The default is `dot'.

    *dot;;
    'dot' draws directed graphs.
    It works well on DAGs and other graphs that can be drawn as hierarchies.
    It  reads attributed graph files and writes drawings.

    *neato;;
    'neato' draws  undirected graphs using ‘‘spring'' models (see Kamada and
    Kawai, Information Processing Letters 31:1, April 1989).
    Input  files must be formatted in the dot attributed graph language.

    *twopi;;
    'twopi'  draws  graphs  using a radial layout (see G. Wills, Symposium on
    Graph Drawing GD'97, September, 1997). 
    Basically, one node  is  chosen as the center and put at the origin.
    The remaining nodes are placed on a sequence of concentric circles
    centered about the origin, each a fixed radial distance from
    the previous circle.

    *circro;;
    'circo' draws graphs using a circular layout (see Six and Tollis, GD  '99
    and  ALENEX  '99, and Kaufmann and Wiese, GD '02.)
    The tool identifies biconnected components and draws the nodes
    of the component on  a  circle.
    The block‐cutpoint tree is then laid out using a recursive radial
    algorithm.
    Edge crossings within a circle are minimized by  placing  as
    many  edges  on  the circle's perimeter as possible.
    In particular, if the component is outerplanar,
    the component will have a planar  layout.

    *fdp;;
     'fdp'  draws undirected graphs using a ‘‘spring'' model.
     It relies on a force‐directed approach in the spirit of Fruchterman
     and Reingold 
     (cf.  Software‐Practice & Experience 21(11), 1991, pp. 1129‐1164).