From: Emden R. Gansner <erg@alum.mit.edu>
Date: Wed, 1 Oct 2014 16:38:15 +0000 (-0400)
Subject: Fix twopi to allow root as a node attribute, and allow multiple usages
X-Git-Tag: TRAVIS_CI_BUILD_EXPERIMENTAL~157
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3c9ce30f37b15b2b72214b7bc901582b0fd40b04;p=graphviz

Fix twopi to allow root as a node attribute, and allow multiple usages
in order to specify the roots of separate components.
---

diff --git a/doc/info/attrs.html b/doc/info/attrs.html
index faadeccb3..215f590ee 100644
--- a/doc/info/attrs.html
+++ b/doc/info/attrs.html
@@ -1718,7 +1718,7 @@ of the layout programs.
 <DT><A NAME=d:root HREF=#a:root><STRONG>root</STRONG></A>
 <DD>  This specifies nodes to be used as the center of the
   layout and the root of the generated spanning tree. As a graph attribute,
-  this gives the name of the node. As a node attribute (circo only), it
+  this gives the name of the node. As a node attribute, it
   specifies that the node should be used as a central node. In twopi,
   this will actually be the central node. In circo, the block containing
   the node will be central in the drawing of its connected component.
@@ -1727,6 +1727,10 @@ of the layout programs.
   <P>
   If the root attribute is defined as the empty string, twopi will reset it
   to name of the node picked as the root node.
+  <P>
+  For twopi, it is possible to have multiple roots, presumably one for each
+  component. If more than one node in a component is marked as the root, twopi
+  will pick one.
 
 <DT><A NAME=d:rotate HREF=#a:rotate><STRONG>rotate</STRONG></A>
 <DD>  If 90, set drawing orientation to landscape.
diff --git a/doc/infosrc/attrs b/doc/infosrc/attrs
index e534a183a..9196884f3 100644
--- a/doc/infosrc/attrs
+++ b/doc/infosrc/attrs
@@ -1129,7 +1129,7 @@ This is a synonym for the <A HREF=#d:dpi>dpi</A> attribute.
 :root:GN:string/bool:<none>(graphs)/false(nodes);  twopi,circo
 This specifies nodes to be used as the center of the
 layout and the root of the generated spanning tree. As a graph attribute,
-this gives the name of the node. As a node attribute (circo only), it
+this gives the name of the node. As a node attribute, it
 specifies that the node should be used as a central node. In twopi,
 this will actually be the central node. In circo, the block containing
 the node will be central in the drawing of its connected component.
@@ -1138,6 +1138,10 @@ twopi will pick a most central node, and circo will pick a random node.
 <P>
 If the root attribute is defined as the empty string, twopi will reset it
 to name of the node picked as the root node.
+<P>
+For twopi, it is possible to have multiple roots, presumably one for each
+component. If more than one node in a component is marked as the root, twopi
+will pick one.
 :rotate:G:int:0;
 If 90, set drawing orientation to landscape.
 :rotation:G:double:0;   sfdp
diff --git a/lib/twopigen/twopiinit.c b/lib/twopigen/twopiinit.c
index a5fabeb82..ff9ea1165 100644
--- a/lib/twopigen/twopiinit.c
+++ b/lib/twopigen/twopiinit.c
@@ -59,6 +59,17 @@ void twopi_init_graph(graph_t * g)
     twopi_init_node_edge(g);
 }
 
+static Agnode_t* findRootNode (Agraph_t* sg, Agsym_t* rootattr)
+{
+    Agnode_t* n;
+
+    for (n = agfstnode(sg); n; n = agnxtnode(sg,n)) {
+	if (mapbool(agxget(n,rootattr))) return n;
+    }
+    return NULL;
+
+}
+
 /* twopi_layout:
  */
 void twopi_layout(Agraph_t * g)
@@ -66,14 +77,15 @@ void twopi_layout(Agraph_t * g)
     Agnode_t *ctr = 0;
     char *s;
     int setRoot = 0;
+    int setLocalRoot = 0;
     pointf sc;
     int doScale = 0;
     int r;
+    Agsym_t* rootattr;
 
     if (agnnodes(g) == 0) return;
 
     twopi_init_graph(g);
-    s = agget(g, "root");
     if ((s = agget(g, "root"))) {
 	if (*s) {
 	    ctr = agfindnode(g, s);
@@ -87,6 +99,9 @@ void twopi_layout(Agraph_t * g)
 	    setRoot = 1;
 	}
     }
+    if ((rootattr = agattr(g, AGNODE, "root", 0))) {
+	setLocalRoot = 1;
+    }
 
     if ((s = agget(g, "scale")) && *s) {
 	if ((r = sscanf (s, "%lf,%lf",&sc.x,&sc.y))) {
@@ -102,12 +117,19 @@ void twopi_layout(Agraph_t * g)
 	Agnode_t *n;
 	int ncc;
 	int i;
+	Agnode_t* lctr;
 
 	ccs = ccomps(g, &ncc, 0);
 	if (ncc == 1) {
-	    c = circleLayout(g, ctr);
+	    if (ctr)
+		lctr = ctr;
+	    else if (!(lctr = findRootNode(g, rootattr)))
+		lctr = 0;
+	    c = circleLayout(g, lctr);
 	    if (setRoot && !ctr)
 		ctr = c;
+	    if (setLocalRoot && !lctr)
+		agxset (c, rootattr, "1"); 
 	    n = agfstnode(g);
 	    free(ND_alg(n));
 	    ND_alg(n) = NULL;
@@ -121,13 +143,15 @@ void twopi_layout(Agraph_t * g)
 	    for (i = 0; i < ncc; i++) {
 		sg = ccs[i];
 		if (ctr && agcontains(sg, ctr))
-		    c = ctr;
-		else
-		    c = 0;
+		    lctr = ctr;
+		else if (!(lctr = findRootNode(sg, rootattr)))
+		    lctr = 0;
 		nodeInduce(sg);
-		c = circleLayout(sg, c);
+		c = circleLayout(sg, lctr);
 	        if (setRoot && !ctr)
 		    ctr = c;
+		if (setLocalRoot && (!lctr || (lctr == ctr)))
+		    agxset (c, rootattr, "1"); 
 		adjustNodes(sg);
 	    }
 	    n = agfstnode(g);