Labels / text on the nodes of a D3 force directed graph

问题

I still not understanding why the code bellow does not display its labels / text... I have defined the css and set the attribute like the title when the move is over the node:

Json:

{
 "nodes":[
   {"name":"t1","group":1},
   {"name":"t2","group":1},
   {"name":"t3","group":1}, 
   {"name":"t4","group":1},
   {"name":"hate","group":2},
   {"name":"good","group":2},
   {"name":"aiport","group":3},
   {"name":"flight","group":3}
 ],
 "links":[
   {"source":0,"target":4,"value":4},
   {"source":0,"target":5,"value":4},
   {"source":1,"target":4,"value":4},
   {"source":2,"target":5,"value":4},
   {"source":3,"target":5,"value":4},
   {"source":4,"target":6,"value":4},
   {"source":5,"target":6,"value":4},
   {"source":5,"target":7,"value":4}
 ]
}

Code:

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.node {
  fill: #555;
  stroke: #999;
  stroke-width: 1.5px;
}

.link {
  stroke: #999;
  stroke-opacity: .6;
}

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
    <script>

    var width = 1024,
        height = 768;

    var color = d3.scale.category20();

    var force = d3.layout.force()
        .charge(-120)
        .linkDistance(30)
        .size([width, height]);

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

    d3.json("data.json", function(error, graph) {
      force
          .nodes(graph.nodes)
          .links(graph.links)
          .start();

      var link = svg.selectAll("line.link")
          .data(graph.links)
        .enter().append("line")
          .attr("class", "link")
          .style("stroke-width", function(d) { return Math.sqrt(d.value); });

     var node = svg.selectAll("circle.node")
          .data(graph.nodes)

        .enter().append("circle")
          .attr("class", "node")
          .attr("r", 5)
          .style("fill", function(d) { return color(d.group); })
          .call(force.drag);

         node.append("title")
          .text(function(d) { return d.name; });

        node.append("text")
          .text(function(d) { return d.name; });


      force.on("tick", function() {
        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("cx", function(d) { return d.x; })
            .attr("cy", function(d) { return d.y; });

      });
    });

    </script>
  </body>
</html>

回答1:

You are adding the text element inside the circle element - try running your code and have a look at the svg with the DOM inspector. I'm not sure text is allowed there. Instead add the text elements separately - like another rendering of the nodes:

var texts = svg.selectAll("text.label")
                .data(graph.nodes)
                .enter().append("text")
                .attr("class", "label")
                .attr("fill", "black")
                .text(function(d) {  return d.name;  });

force.on("tick", function() {
    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("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; });

    texts.attr("transform", function(d) {
        return "translate(" + d.x + "," + d.y + ")";
    });
});

回答2:

Another option would be to add both circle and text elements inside a g container element as shown below:

var container = svg.selectAll("g.node").data(graph.nodes).enter().append("g")
.attr("class", "node")
.attr("transform", function (d) {
    return "translate(" + d.x + "," + d.y + ")";
}).call(force.drag);

container.append("circle")
.attr("r", 5)
.style("fill", color);

container.append("text")
.style("text-anchor", "middle")
.text(function (d) {
    return d.name;
});

Here you can play with a working jsfiddle:

http://jsfiddle.net/vfu78/16/

来源：https://stackoverflow.com/questions/13364566/labels-text-on-the-nodes-of-a-d3-force-directed-graph

标签

javascript

d3.js

label

force-layout