0.md

CSS-ish styling for graphviz DOT

digraph {
  rb_find_file_safe [class="emph,strong"];
  search_required [class=emph];
  open_load_file [class=emph];
  rb_find_file -> rb_find_file_safe;
  search_required -> rb_find_file_safe;
  rb_require_internal -> search_required;
  load_file -> open_load_file;
  {rank=same search_required rb_find_file_safe open_load_file};
}

gvpr -c -f neato.gv < neato.dot | dot -Tsvg > neato.svg

neato.gv

# Default Styles

BEG_G {
  allDefault($G, "fontname", "helvetica");
  allDefault($G, "fontsize", "10px");

  nodeDefault($G, "style",     "rounded,filled");
  nodeDefault($G, "shape",     "box");
  nodeDefault($G, "fillcolor", "#cee1ff");
  nodeDefault($G, "fontcolor", "#333333");
}

# Classes

N [class($, "emph")] {
  fillcolor = "#ffccff";
  penwidth  = "3";
}

N [class($, "strong")] {
  penwidth  = "3";
  fontcolor = "red";
}

###########################################################

BEGIN {
  void graphDefault(graph_t g, string k, string v) {
    setDflt(g, "G", k, v);
  }

  void edgeDefault(graph_t g, string k, string v) {
    setDflt(g, "E", k, v);
  }

  void nodeDefault(graph_t g, string k, string v) {
    setDflt(g, "N", k, v);
  }

  void allDefault(graph_t g, string k, string v) {
    setDflt(g, "N", k, v);
    setDflt(g, "E", k, v);
    setDflt(g, "G", k, v);
  }

  int class(node_t n, string klass) {
    int c = 0;
    int hasClass = 0;
    string newClasses = "";
    string classes[int];

    if (!hasAttr(n, "class")) return 0;
    unset(classes);
    tokens(aget(n, "class"), classes, ",");
    for (classes[c]) {
      if (classes[c] == klass) {
        hasClass = 1;
      }
    }
    if (!hasClass) return 0;

    unset(classes);
    tokens(aget(n, "class"), classes, ",");
    for (classes[c]) {
      if (classes[c] != klass) {
        if (newClasses == "") {
          newClasses = classes[c];
        } else {
          newClasses = sprintf("%s,%s", newClasses, classes[c]);
        }
      }
    }
    aset(n, "class", newClasses);
    return 1;
  }
}

N [hasAttr($, "class") && (aget($, "class") != "" && aget($, "class") != 0)] {
  printf(2, "diagram.gvpr: unsupported class: %s\n", aget($, "class"));
  exit(1);
}