Allow twopi to note vertex picked as root if not specified

diff --git a/lib/twopigen/circle.c b/lib/twopigen/circle.c
index 67714177da6adfdf5d76f1adcce4685dd0168c3f..7dcdc52b33469402357aeeaee03c317e22768d7a 100644 (file)
--- a/lib/twopigen/circle.c
+++ b/lib/twopigen/circle.c
@@ -339,7 +339,7 @@ static void dumpGraph(Agraph_t * g)
  *  Also, if center != 0, we are guaranteed that center is
  *  in the graph.
  */
-void circleLayout(Agraph_t * sg, Agnode_t * center)
+Agnode_t* circleLayout(Agraph_t * sg, Agnode_t * center)
 {
     int maxNStepsToCenter;
 
@@ -347,7 +347,7 @@ void circleLayout(Agraph_t * sg, Agnode_t * center)
        Agnode_t *n = agfstnode(sg);
        ND_pos(n)[0] = 0;
        ND_pos(n)[1] = 0;
-       return;
+       return center;
     }
 
     initLayout(sg);
@@ -367,4 +367,5 @@ void circleLayout(Agraph_t * sg, Agnode_t * center)
 
     setAbsolutePos(sg, maxNStepsToCenter);
     /* dumpGraph (sg); */
+    return center;
 }

diff --git a/lib/twopigen/circle.h b/lib/twopigen/circle.h
index c54ebb6ad9fafea48804cfc77dd7dc2c07f62357..822f5015f57ad16b17384f8f93dab08b982ba25e 100644 (file)
--- a/lib/twopigen/circle.h
+++ b/lib/twopigen/circle.h
@@ -39,7 +39,7 @@ extern "C" {
 #define SPAN(n) (RDATA(n)->span)
 #define THETA(n) (RDATA(n)->theta)
 
-    extern void circleLayout(Agraph_t * sg, Agnode_t * center);
+    extern Agnode_t* circleLayout(Agraph_t * sg, Agnode_t * center);
     extern void twopi_layout(Agraph_t * g);
     extern void twopi_cleanup(Agraph_t * g);
     extern void twopi_init_graph(graph_t * g);

diff --git a/lib/twopigen/twopiinit.c b/lib/twopigen/twopiinit.c
index 0d3d5e9b03fc35368e3f7bb9346a4945795d3b51..b0ee53b7acbb4f19143f295dded63369f4278e05 100644 (file)
--- a/lib/twopigen/twopiinit.c
+++ b/lib/twopigen/twopiinit.c
@@ -65,14 +65,21 @@ void twopi_layout(Agraph_t * g)
 {
     Agnode_t *ctr = 0;
     char *s;
+    int setRoot = 0;
 
     twopi_init_graph(g);
     s = agget(g, "root");
-    if (s && (*s != '\0')) {
-       ctr = agfindnode(g, s);
-       if (!ctr) {
-           agerr(AGWARN, "specified root node \"%s\" was not found.", s);
-           agerr(AGPREV, "Using default calculation for root node\n");
+    if ((s = agget(g, "root"))) {
+       if (*s) {
+           ctr = agfindnode(g, s);
+           if (!ctr) {
+               agerr(AGWARN, "specified root node \"%s\" was not found.", s);
+               agerr(AGPREV, "Using default calculation for root node\n");
+               setRoot = 1;
+           }
+       }
+       else {
+           setRoot = 1;
        }
     }
     if (agnnodes(g)) {
@@ -84,7 +91,9 @@ void twopi_layout(Agraph_t * g)
 
        ccs = ccomps(g, &ncc, 0);
        if (ncc == 1) {
-           circleLayout(g, ctr);
+           c = circleLayout(g, ctr);
+           if (setRoot && !ctr)
+               ctr = c;
            free(ND_alg(agfstnode(g)));
            adjustNodes(g);
            spline_edges(g);
@@ -100,7 +109,9 @@ void twopi_layout(Agraph_t * g)
                else
                    c = 0;
                nodeInduce(sg);
-               circleLayout(sg, c);
+               c = circleLayout(sg, c);
+               if (setRoot && !ctr)
+                   ctr = c;
                adjustNodes(sg);
                setEdgeType (sg, ET_LINE);
                spline_edges(sg);
@@ -113,6 +124,8 @@ void twopi_layout(Agraph_t * g)
        }
        free(ccs);
     }
+    if (setRoot)
+       agset (g, "root", agnameof (ctr)); 
     dotneato_postprocess(g);
 
 }