D3 Network With Multiple Links In The Same Direction

I am attempting to alter the Mobile Patent Suits example to allow for multiple links in one direction. I have data (yes, I know Jim isn't actually Pam's boss): source tar

Solution 1:

There are probable a few potential approaches for this, one comes to mind rather quickly: use a different path generator for each type relationship between the nodes. You'll have to have a property indicating the nature of the relationship (which you have in your question), and use that to set the path alignment.

In the snippet below I check to see what relationship is being drawn, and reduce the radius of the arc in a personal relationship by 50% as compared to the professional relationship arc radius. The relevant part is:

functionlinkArc(d) {

  var dx = d.target.x - d.source.x,
      dy = d.target.y - d.source.y,
      dr = Math.sqrt(dx * dx + dy * dy);
  if(d.relationship == "pro") { 
     return"M" + d.source.x + "," + d.source.y + "A" + dr + "," + dr + " 0 0,1 " + d.target.x + "," + d.target.y;
  }
  else {
    return"M" + d.source.x + "," + d.source.y + "A" + (dr * 0.3) + "," + (dr * 0.3) + " 0 0,1 " + d.target.x + "," + d.target.y;
  }
}

Here's the whole thing in practice:

var links = [
  { source: "Michael Scott",
    target:"Jan Levenson",
    relationship: "pro"
  },
  { source:"Jan Levenson",
    target:"Michael Scott",
    relationship: "Personal"
  },
  { source: "Jim Halpert",
    target: "Pam Beasley",
    relationship: "pro"
  },
  {
    source: "Jim Halpert",
    target: "Pam Beasley",
    relationship: "Personal" 
  }
  ]
  
  var nodes = {};

// Compute the distinct nodes from the links.
links.forEach(function(link) {
  link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
  link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
});

var width = 960,
    height = 500;

var force = d3.layout.force()
    .nodes(d3.values(nodes))
    .links(links)
    .size([width, height])
    .linkDistance(60)
    .charge(-300)
    .on("tick", tick)
    .start();

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

// Per-type markers, as they don't inherit styles.
svg.append("defs").selectAll("marker")
    .data(["suit", "licensing", "resolved"])
  .enter().append("marker")
    .attr("id", function(d) { return d; })
    .attr("viewBox", "0 -5 10 10")
    .attr("refX", 15)
    .attr("refY", -1.5)
    .attr("markerWidth", 6)
    .attr("markerHeight", 6)
    .attr("orient", "auto")
  .append("path")
    .attr("d", "M0,-5L10,0L0,5");

var path = svg.append("g").selectAll("path")
    .data(force.links())
  .enter().append("path")
    .attr("class", function(d) { return"link " + d.type; })
    .attr("marker-end", function(d) { return"url(#" + d.type + ")"; });

var circle = svg.append("g").selectAll("circle")
    .data(force.nodes())
  .enter().append("circle")
    .attr("r", 6)
    .call(force.drag);

var text = svg.append("g").selectAll("text")
    .data(force.nodes())
  .enter().append("text")
    .attr("x", 8)
    .attr("y", ".31em")
    .text(function(d) { return d.name; });

// Use elliptical arc path segments to doubly-encode directionality.functiontick() {
  path.attr("d", linkArc);
  circle.attr("transform", transform);
  text.attr("transform", transform);
}

functionlinkArc(d) {

  var dx = d.target.x - d.source.x,
      dy = d.target.y - d.source.y,
      dr = Math.sqrt(dx * dx + dy * dy);
  if(d.relationship == "pro") { 
     return"M" + d.source.x + "," + d.source.y + "A" + dr + "," + dr + " 0 0,1 " + d.target.x + "," + d.target.y;
  }
  else {
    return"M" + d.source.x + "," + d.source.y + "A" + (dr * 0.3) + "," + (dr * 0.3) + " 0 0,1 " + d.target.x + "," + d.target.y;
  }
}

functiontransform(d) {
  return"translate(" + d.x + "," + d.y + ")";
}

.link {
  fill: none;
  stroke: #666;
  stroke-width: 1.5px;
}

#licensing {
  fill: green;
}

.link.licensing {
  stroke: green;
}

.link.resolved {
  stroke-dasharray: 0,21;
}

circle {
  fill: #ccc;
  stroke: #333;
  stroke-width: 1.5px;
}

text {
  font: 10px sans-serif;
  pointer-events: none;
  text-shadow: 01px0#fff, 1px00#fff, 0 -1px0#fff, -1px00#fff;
}

<scriptsrc="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>