From 446eb651eebb02bc857c421bde13aeee7a741b97 Mon Sep 17 00:00:00 2001
From: Chris Pettitt <cpettitt@gmail.com>
Date: Mon, 31 Mar 2014 21:04:56 -0700
Subject: [PATCH] Add debug tool for positioning phase

---
 lib/debug.js | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/lib/debug.js b/lib/debug.js
index 416bd75a..9ab22e37 100644
--- a/lib/debug.js
+++ b/lib/debug.js
@@ -53,3 +53,39 @@ exports.dotOrdering = function(g) {
 
   return result;
 };
+
+/**
+ * Renders a graph in a stringified DOT format that indicates the position of
+ * of all of the nodes in the graph. This is best used with neato - dot does
+ * not appear to respect position information.
+ */
+exports.dotPositioning = function(g) {
+  var result = 'digraph {',
+      scale = 0.1; // scale factor for graphviz
+
+  g.eachNode(function(u, attrs) {
+    if (!g.children(u).length) {
+      result += u + ' [pos="' + (attrs.x * scale) + ',' + (-attrs.y * scale) + '!"';
+      if (attrs.dummy) {
+        result += ', shape=diamond';
+      } else if (attrs.rightBorderSegment) {
+        result += ', shape=larrow';
+      } else if (attrs.leftBorderSegment) {
+        result += ', shape=rarrow';
+      } else if (attrs.nestingGraphTop) {
+        result += ', shape=invtriangle';
+      } else if (attrs.nestingGraphBottom) {
+        result += ', shape=triangle';
+      }
+      result += ', label="' + u + ' ' + attrs.x + ',' + attrs.y + '"];';
+    }
+  });
+
+  g.eachEdge(function(e, u, v) {
+    result += u + '->' + v + ';';
+  });
+
+  result += '}';
+
+  return result;
+};