mbostock · March 20, 2019 02:55 · Feb 9, 2016 · Oct 31, 2015 · Jun 11, 2015 · Jun 11, 2015
diff --git a/.block b/.block
@@ -0,0 +1 @@
+license: gpl-3.0
diff --git a/index.html b/index.html
@@ -23,7 +23,7 @@
 
 </style>
 <body>
-<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
+<script src="//d3js.org/d3.v3.min.js"></script>
 <script>
 
 var width = 960,

diff --git a/index.html b/index.html
@@ -44,7 +44,7 @@
     .linkDistance(function(d) { return radius(d.source.size) + radius(d.target.size) + 20; });
 
 d3.json("graph.json", function(error, graph) {
-  if (error) return console.error(error);
+  if (error) throw error;
 
   force
       .nodes(graph.nodes)

diff --git a/index.html b/index.html
@@ -23,7 +23,7 @@
 
 </style>
 <body>
-<script src="http://d3js.org/d3.v2.min.js?2.9.6"></script>
+<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
 <script>
 
 var width = 960,
@@ -43,7 +43,9 @@
     .charge(-400)
     .linkDistance(function(d) { return radius(d.source.size) + radius(d.target.size) + 20; });
 
-d3.json("graph.json", function(graph) {
+d3.json("graph.json", function(error, graph) {
+  if (error) return console.error(error);
+
   force
       .nodes(graph.nodes)
       .links(graph.links)

diff --git a/graph.json b/graph.json
@@ -3,7 +3,7 @@
     {"atom": "C", "size": 12},
     {"atom": "C", "size": 12},
     {"atom": "C", "size": 12},
-    {"atom": "N", "size": 7},
+    {"atom": "N", "size": 14},
     {"atom": "H", "size": 1},
     {"atom": "O", "size": 16},
     {"atom": "O", "size": 16},

diff --git a/thumbnail.png b/thumbnail.png
diff --git a/index.html b/index.html
@@ -32,7 +32,7 @@
 var color = d3.scale.category20();
 
 var radius = d3.scale.sqrt()
-    .range([0, 8]);
+    .range([0, 6]);
 
 var svg = d3.select("body").append("svg")
     .attr("width", width)

diff --git a/index.html b/index.html
@@ -41,7 +41,7 @@
 var force = d3.layout.force()
     .size([width, height])
     .charge(-400)
-    .linkDistance(60);
+    .linkDistance(function(d) { return radius(d.source.size) + radius(d.target.size) + 20; });
 
 d3.json("graph.json", function(graph) {
   force

diff --git a/index.html b/index.html
@@ -32,7 +32,7 @@
 var color = d3.scale.category20();
 
 var radius = d3.scale.sqrt()
-    .range([0, 12]);
+    .range([0, 8]);
 
 var svg = d3.select("body").append("svg")
     .attr("width", width)
@@ -41,7 +41,7 @@
 var force = d3.layout.force()
     .size([width, height])
     .charge(-400)
-    .linkDistance(40);
+    .linkDistance(60);
 
 d3.json("graph.json", function(graph) {
   force
@@ -73,6 +73,7 @@
 
   node.append("text")
       .attr("dy", ".35em")
+      .attr("text-anchor", "middle")
       .text(function(d) { return d.atom; });
 
   function tick() {

diff --git a/index.html b/index.html
@@ -32,7 +32,7 @@
 var color = d3.scale.category20();
 
 var radius = d3.scale.sqrt()
-    .range([0, 3]);
+    .range([0, 12]);
 
 var svg = d3.select("body").append("svg")
     .attr("width", width)
@@ -72,9 +72,8 @@
       .style("fill", function(d) { return color(d.atom); });
 
   node.append("text")
-      .attr("x", function(d) { return radius(d.size) + 6; })
       .attr("dy", ".35em")
-      .text(function(d) {return d.atom; });
+      .text(function(d) { return d.atom; });
 
   function tick() {
     link.selectAll("line")

diff --git a/README.md b/README.md
@@ -0,0 +1 @@
+This is a quick hack to draw two parallel links between nodes. Yes, you can scale it to more than two nodes, but it gets increasingly awkward. The alternative is to compute the paths manually, say by computing the [perpendicular vector](http://mathworld.wolfram.com/PerpendicularVector.html) of the vector between the node centers, and offsetting the links accordingly.
diff --git a/graph.json b/graph.json
@@ -0,0 +1,31 @@
+{
+  "nodes": [
+    {"atom": "C", "size": 12},
+    {"atom": "C", "size": 12},
+    {"atom": "C", "size": 12},
+    {"atom": "N", "size": 7},
+    {"atom": "H", "size": 1},
+    {"atom": "O", "size": 16},
+    {"atom": "O", "size": 16},
+    {"atom": "H", "size": 1},
+    {"atom": "H", "size": 1},
+    {"atom": "H", "size": 1},
+    {"atom": "H", "size": 1},
+    {"atom": "H", "size": 1},
+    {"atom": "H", "size": 1}
+  ],
+  "links": [
+    {"source": 0, "target": 1,  "bond": 1},
+    {"source": 1, "target": 2,  "bond": 1},
+    {"source": 1, "target": 3,  "bond": 1},
+    {"source": 2, "target": 5,  "bond": 2},
+    {"source": 2, "target": 6,  "bond": 1},
+    {"source": 1, "target": 4,  "bond": 1},
+    {"source": 3, "target": 10, "bond": 1},
+    {"source": 3, "target": 11, "bond": 1},
+    {"source": 0, "target": 7,  "bond": 1},
+    {"source": 0, "target": 8,  "bond": 1},
+    {"source": 0, "target": 9,  "bond": 1},
+    {"source": 5, "target": 12, "bond": 1}
+  ]
+}
diff --git a/index.html b/index.html
@@ -0,0 +1,89 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<style>
+
+.link line {
+  stroke: #696969;
+}
+
+.link line.separator {
+  stroke: #fff;
+  stroke-width: 2px;
+}
+
+.node circle {
+  stroke: #000;
+  stroke-width: 1.5px;
+}
+
+.node text {
+  font: 10px sans-serif;
+  pointer-events: none;
+}
+
+</style>
+<body>
+<script src="http://d3js.org/d3.v2.min.js?2.9.6"></script>
+<script>
+
+var width = 960,
+    height = 500;
+
+var color = d3.scale.category20();
+
+var radius = d3.scale.sqrt()
+    .range([0, 3]);
+
+var svg = d3.select("body").append("svg")
+    .attr("width", width)
+    .attr("height", height);
+
+var force = d3.layout.force()
+    .size([width, height])
+    .charge(-400)
+    .linkDistance(40);
+
+d3.json("graph.json", function(graph) {
+  force
+      .nodes(graph.nodes)
+      .links(graph.links)
+      .on("tick", tick)
+      .start();
+
+  var link = svg.selectAll(".link")
+      .data(graph.links)
+    .enter().append("g")
+      .attr("class", "link");
+
+  link.append("line")
+      .style("stroke-width", function(d) { return (d.bond * 2 - 1) * 2 + "px"; });
+
+  link.filter(function(d) { return d.bond > 1; }).append("line")
+      .attr("class", "separator");
+
+  var node = svg.selectAll(".node")
+      .data(graph.nodes)
+    .enter().append("g")
+      .attr("class", "node")
+      .call(force.drag);
+
+  node.append("circle")
+      .attr("r", function(d) { return radius(d.size); })
+      .style("fill", function(d) { return color(d.atom); });
+
+  node.append("text")
+      .attr("x", function(d) { return radius(d.size) + 6; })
+      .attr("dy", ".35em")
+      .text(function(d) {return d.atom; });
+
+  function tick() {
+    link.selectAll("line")
+        .attr("x1", function(d) { return d.source.x; })
+        .attr("y1", function(d) { return d.source.y; })
+        .attr("x2", function(d) { return d.target.x; })
+        .attr("y2", function(d) { return d.target.y; });
+
+    node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
+  }
+});
+</script>
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		This is a quick hack to draw two parallel links between nodes. Yes, you can scale it to more than two nodes, but it gets increasingly awkward. The alternative is to compute the paths manually, say by computing the [perpendicular vector](http://mathworld.wolfram.com/PerpendicularVector.html) of the vector between the node centers, and offsetting the links accordingly.