Use graphviz v1

Author: james-d-mitchell

PackageInfo.g

@@ -379,6 +379,7 @@ Dependencies := rec(
   NeededOtherPackages := [["datastructures", ">=0.2.5"],
                           ["digraphs", ">=1.6.2"],
                           ["genss", ">=1.6.5"],
+                          ["graphviz", ">=0.0.0"],
                           ["images", ">=1.3.1"],
                           ["IO", ">=4.5.1"],
                           ["orb", ">=4.8.2"]],

gap/tools/display.gi

@@ -731,6 +731,8 @@ function(D)
   local S, edge_colors, N, msg, legend, node_labels, offset, en, label, next,
   edge_func, node_func, result, i;
 
+  # TODO replace with an appropriate call to DotWordGraph
+
   S := SemigroupOfCayleyDigraph(D);
   edge_colors := ["\"#00ff00\"", "\"#ff00ff\"", "\"#007fff\"", "\"#ff7f00\"",
                   "\"#7fbf7f\"", "\"#4604ac\"", "\"#de0328\"", "\"#19801d\"",
@@ -755,6 +757,8 @@ function(D)
     if IsOne(en[i]) then
       label := "ε";
     else
+      # TODO maybe reuse some of this it seems to give better factorisations,
+      # than the DotRightCayleyDigraph method below
       label := SEMIGROUPS.WordToExtRepObj(MinimalFactorization(S, i) + offset);
       label := SEMIGROUPS.ExtRepObjToString(label);
     fi;
@@ -805,88 +809,139 @@ function(D)
 end);
 
 InstallMethod(DotLeftCayleyDigraph, "for a semigroup", [IsSemigroup],
-S -> DotString(LeftCayleyDigraph(S)));
+function(S)
+  local label;
+  label := x -> SEMIGROUPS.WordToString(MinimalFactorization(S, x));
+  return DotWordGraph(LeftCayleyDigraph(S),
+                      List(S, label),
+                      List(GeneratorsOfSemigroup(S), label));
+end);
 
 InstallMethod(DotRightCayleyDigraph, "for a semigroup", [IsSemigroup],
-S -> DotString(RightCayleyDigraph(S)));
+function(S)
+  local label;
+
+  # TODO handle monoids
+  # ToExtRepObj := SEMIGROUPS.WordToExtRepObj;
+  # ToString    := SEMIGROUPS.ExtRepObjToString;
+  # label := x -> ToString(ToExtRepObj(MinimalFactorization(S, x)));
+  # Current the above approach doesn't work becase labels aren't put into
+  # quotes " by default and so an error is given for this at present.
+  # TODO delete the next line when graphviz is fixed.
+  label := x -> SEMIGROUPS.WordToString(MinimalFactorization(S, x));
+  return DotWordGraph(RightCayleyDigraph(S),
+                      List(S, label),
+                      List(GeneratorsOfSemigroup(S), label));
+end);
 
-InstallMethod(DotWordGraph, "for a word graph and list of edge labels",
-[IsDigraph, IsList, IsList],
+InstallMethod(DotWordGraph,
+"for a word graph, list of node labels, and list of edge labels",
+[IsDigraph, IsHomogeneousList, IsHomogeneousList],
 function(D, node_labels, edge_labels)
-  local M, N, edge_colors, msg, legend, label, next, node_func, edge_func, result, v, i;
+  local M, N, msg, edge_colors, dot, mm, pos, targets, e, legend, subgraph,
+  key, key2, label, next, str, m, n, i;
+
+  # TODO have some options, like include the legend, maybe fancy labels
 
-  if IsNullDigraph(D) then
+  if not DigraphHasAVertex(D) then
     # Word graphs must have at least one node . . .
-    ErrorNoReturn("TODO3");
+    ErrorNoReturn("The 1st argument (a digraph) must have at least one vertex");
+  elif not IsOutRegularDigraph(D) then
+    ErrorNoReturn("The 1st argument (a digraph) must be out-regular");
   fi;
 
   M := DigraphNrVertices(D);
   N := Length(OutNeighboursOfVertex(D, 1));
-
-  if not IsOutRegularDigraph(D) then
-    ErrorNoReturn("TODO1");
+  if Length(node_labels) <> M then
+    msg := "Expected the 2nd argument (a list) to have length ";
+    Append(msg, "{}, but found {}");
+    ErrorNoReturn(StringFormatted(msg), M, Length(node_labels));
+  elif not IsString(node_labels[1]) then
+    ErrorNoReturn("TODO");
   elif Length(edge_labels) <> N then
-    ErrorNoReturn("TODO2");
+    msg := "Expected the 3rd argument (a list) to have length ";
+    Append(msg, "{}, but found {}");
+    ErrorNoReturn(msg, M, Length(edge_labels));
+  elif not IsString(edge_labels[1]) then
+    ErrorNoReturn("TODO");
   fi;
 
-  edge_colors := ["\"#00ff00\"", "\"#ff00ff\"", "\"#007fff\"", "\"#ff7f00\"",
-                  "\"#7fbf7f\"", "\"#4604ac\"", "\"#de0328\"", "\"#19801d\"",
-                  "\"#d881f5\"", "\"#00ffff\"", "\"#ffff00\"", "\"#00ff7f\"",
-                  "\"#ad5867\"", "\"#85f610\"", "\"#84e9f5\"", "\"#f5c778\"",
-                  "\"#207090\"", "\"#764ef3\"", "\"#7b4c00\"", "\"#0000ff\"",
-                  "\"#b80c9a\"", "\"#601045\"", "\"#29b7c0\"", "\"#839f12"];
+  # TODO longer list here
+  edge_colors := ["#00ff00", "#ff00ff", "#007fff", "#ff7f00",
+                  "#7fbf7f", "#4604ac", "#de0328", "#19801d",
+                  "#d881f5", "#00ffff", "#ffff00", "#00ff7f",
+                  "#ad5867", "#85f610", "#84e9f5", "#f5c778",
+                  "#207090", "#764ef3", "#7b4c00", "#0000ff",
+                  "#b80c9a", "#601045", "#29b7c0", "#839f12"];
 
   if N > Length(edge_colors) then
-    msg := Concatenation("the out-degree of every vertex in the 1st argument (a digraph) ",
-                         "must have at most {}, found {}");
+    msg := Concatenation("the out-degree of every vertex in the 1st argument ",
+                         "(a digraph) must be at most {}, found {}");
     ErrorNoReturn(StringFormatted(msg, Length(edge_colors), N));
   fi;
 
-  # node_labels := ["&#949;"];
+  dot := GV_Digraph("WordGraph");
+  GV_SetAttr(dot, "node [shape=\"box\"]");
+  for m in [1 .. M] do
+    mm := GV_AddNode(dot, m);
+    GV_SetAttr(mm, "label", node_labels[m]);
+    pos := Position(edge_labels, node_labels[m]);
+    if pos <> fail then
+      GV_SetAttr(mm, "color", edge_colors[pos]);
+      GV_SetAttr(mm, "style", "filled");
+    fi;
+  od;
 
-  # for v in [2 .. M] do
-  #   Add(node_labels, edge_labels{DigraphPath(D, 1, v)[2]});
-  # od;
+  for m in [1 .. M] do
+    targets := OutNeighboursOfVertex(D, m);
+    for n in [1 .. N] do
+      e := GV_AddEdge(dot, m, targets[n]);
+      GV_SetAttr(e, "color", edge_colors[n]);
+    od;
+  od;
 
-  legend := "node [shape=plaintext]\nsubgraph cluster_01 {\nlabel=\"Legend\"\n";
-  Append(legend, "key2 [label=<<table border=\"0\" cellpadding=\"2\"");
-  Append(legend, " cellspacing=\"0\" cellborder=\"0\">\n");
+  legend := GV_AddContext(dot, "legend");
+  GV_SetAttr(legend, "node [shape=plaintext]");
+  subgraph := GV_AddSubgraph(legend, "legend");
+  key := GV_AddNode(subgraph, "key");
+  key2 := GV_AddNode(subgraph, "key2");
 
+  label := Concatenation("<<table border=\"0\" cellpadding=\"2\"",
+                         " cellspacing=\"0\"",
+                         " cellborder=\"0\">\n");
   for i in [1 .. N] do
-    Append(legend,
+    Append(label,
            StringFormatted("  <tr><td port=\"i{}\">&nbsp;</td></tr>\n",
                            i));
   od;
-  Append(legend, "</table>>]\n");
-  Append(legend, "key [label=<<table border=\"0\" cellpadding=\"2\"");
-  Append(legend, " cellspacing=\"0\" cellborder=\"0\">\n");
+  Append(label, "</table>>\n");
+  GV_SetAttr(key2, "label", label);
 
+  # TODO remove code dupl
+  label := Concatenation("<<table border=\"0\" cellpadding=\"2\"",
+                         " cellspacing=\"0\"",
+                         " cellborder=\"0\">\n");
   for i in [1 .. N] do
-    label := [edge_labels[i]];
-    next := "<tr><td align=\"right\" ";
-    Append(next, StringFormatted("port=\"i{}\">{}&nbsp;</td></tr>\n", i, label));
-    Append(legend, next);
+    next := "    <tr><td align=\"right\" ";
+    Append(next, StringFormatted("port=\"i{}\">{}&nbsp;</td></tr>\n",
+                                 i,
+                                 edge_labels[i]));
+    Append(label, next);
   od;
+  Append(label, "</table>>\n");
 
-  Append(legend, "</table>>]\n\n");
+  GV_SetAttr(key, "label", label);
 
   for i in [1 .. N] do
-    next := StringFormatted("key:i{1}:e -> key2:i{1}:w [color={2},",
-                            i,
-                            edge_colors[i]);
-    Append(next, "constraint=false]\n");
-    Append(legend, next);
+    e := GV_AddEdge(subgraph,
+                    StringFormatted("key:i{}:e", i),
+                    StringFormatted("key2:i{}:w", i));
+    GV_SetAttr(e, "color", edge_colors[i]);
+    GV_SetAttr(e, "constraint", false);
   od;
-  Append(legend, "}\n");
-
-  node_func := i -> StringFormatted(" [label=\"{}\"]", node_labels[i]);
-  edge_func := {i, j} -> StringFormatted("[color={}]", edge_colors[j]);
 
-  result := DIGRAPHS_DotDigraph(D, [node_func], [edge_func]);
-  result := SplitString(result, "\n");
-  result[3] := "subgraph 00 {";
-  Add(result, "node [shape=box]", 3);
-  Add(result, legend);
-  Add(result, "}");
-  return JoinStringsWithSeparator(result, "\n");
+  str := GV_String(dot);
+  # TODO remove the next two lines, these work around some issues in graphviz
+  str := ReplacedString(str, "--", "->");
+  return Concatenation("//dot\n", str);
 end);