javascript - Breaking text from json into several lines for displaying labels in a D3 force layout

Question

I am new to d3.js and coding in general. This is my question:

I am trying to find a way to break long displayed names of force layout objects in lines.

I would like to be able to determine where to break these lines, and I am guessing this is something that might be possible to be done from the json file.

I am aware that there have been similar questions asked already, but I just can't find where to put the code or why my previous attempts haven't been successful. This is the code that I have:

var width = 960,
    height = 800,
    root;

var force = d3.layout.force()
    .linkDistance(120)
    .charge(-600)
    .gravity(.06)
    .size([width, height])
    .on("tick", tick);

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

var link = svg.selectAll(".link"),
    node = svg.selectAll(".node");

d3.json("graph.json", function(error, json) {
  root = json;
  update();
});

function update() {
  var nodes = flatten(root),
      links = d3.layout.tree().links(nodes);


  // Restart the force layout.
  force
      .nodes(nodes)
      .links(links)
      .start();

  // Update links.
  link = link.data(links, function(d) { return d.target.id; });

  link.exit().remove();

  link.enter().insert("line", ".node")
      .attr("class", "link");

  // Update nodes.
  node = node.data(nodes, function(d) { return d.id; });

  node.exit().remove();

  var nodeEnter = node.enter().append("g")  
      .attr("class", "node")
      .on("click", click)
      .call(force.drag);

  nodeEnter.append("circle")
      .attr("r", function(d) { return Math.sqrt(d.size) / 3 || 10; });

  nodeEnter.append("text")
      .attr("dy", "0.3em")
      .text(function(d) { return d.name; });

  node.select("circle")
      .style("fill", color);
}

// Divide text

text.append("text")       
    .each(function (d) {
    var arr = d.name.split(" ");
    if (arr != undefined) {
        for (i = 0; i < arr.length; i++) {
            d3.select(this).append("tspan")
                .text(arr[i])
                .attr("dy", i ? "1.2em" : 0)
                .attr("x", 0)
                .attr("text-anchor", "middle")
                .attr("class", "tspan" + i);
        }
    }
});

// Divide text

function tick() {
  link.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 + ")"; });
}

function color(d) {
  return d._children ? "#9ecae1" // collapsed package
      : d.children ? "#ffffff" // expanded package
      : "#ffcc50"; // leaf node
}


// Toggle children on click.
function click(d) {
  if (d3.event.defaultPrevented) return; // ignore drag
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else if (d._children) {
    d.children = d._children;
    d._children = null;
  } else {
    // This was a leaf node, so redirect.
    window.open(d.url, 'popUpWindow','height=600,width=800,left=10,top=10,resizable=yes,scrollbars=no,toolbar=no,menubar=no,location=no,directories=no,status=yes');
  }
  update();
}

// Returns a list of all nodes under the root.
function flatten(root) {
  var nodes = [], i = 0;

  function recurse(node) {
    if (node.children) node.children.forEach(recurse);
    if (!node.id) node.id = ++i;
    nodes.push(node);
  }

  recurse(root);
  return nodes;
}

And this is the json info:

{
 "name": "flare",
 "children": [
  {
   "name": "analytics",
   "children": [
    {
     "name": "cluster",
     "children": [
      {"name": "Agglomerative Cluster", "size": 3938},
      {"name": "Community Structure", "size": 3812},
      {"name": "Hierarchical Cluster", "size": 6714},
      {"name": "Merge Edge", "size": 743}
     ]
    },
    {
     "name": "graph",
     "children": [
      {"name": "Betweenness Centrality", "size": 3534},
      {"name": "Link Distance", "size": 5731},
      {"name": "Max Flow Min Cut", "size": 7840},
      {"name": "Shortest Paths", "size": 5914},
      {"name": "Spanning Tree", "size": 3416}
     ]
    },
    {
     "name": "optimization",
     "children": [
      {"name": "Aspect Ratio Banker", "size": 7074}
     ]
    }
   ]
  }
 ]

I would like to be able to decide, for example, to break Aspect / Ratio Banker or Aspect Ratio / Banker.

Answer 1

I believe this example on jsfiddle solves your problem.

The code is actually your example, just a little bit modified.

There is a new function wordwrap2() that takes care of proper splitting of the names:

function wordwrap2( str, width, brk, cut ) {
    brk = brk || '
';
    width = width || 75;
    cut = cut || false;
    if (!str) { return str; }
    var regex = '.{1,' +width+ '}(\s|$)' + (cut ? '|.{' +width+ '}|.+$' : '|\S+?(\s|$)');
    return str.match( RegExp(regex, 'g') ).join( brk );
}

Then, there is a new important part of the code that, instead of just creating one text label per node, creates this:

  var maxLength = 20;
  var separation = 18;
  var textX = 0;
  nodeEnter.append("text")
      .attr("dy", "0.3em")
      .each(function (d) {
          var lines = wordwrap2(d.name, maxLength).split('
');
          console.log(d.name);
          console.log(lines);
          for (var i = 0; i < lines.length; i++) {
              d3.select(this)
                .append("tspan")
                .attr("dy", separation)
                .attr("x", textX)
                .text(lines[i]);
           }
    });

(variable maxLength - length used for criterium for splitting names)

(variable separation - visual vertical distance between split lines of a name)

For example this would be the output for maxLength=20:

This would be the output for maxLength=15: (notice that Aspect Ratio Banker became Aspect Ratio/Banker)

This would be the output for maxLength=10: (now, check out Aspect/Ratio/Banker !)

And this would be the output for maxLength=10 and separation=30 (a little more space between individual lines):