D3 Examples - Metis Class 7, #1

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<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>
​
<body>
  <script>
    /*if we just want to link nodes and position them, 
don't use force link, instead create a link function and use focusX and focusY and force collide*/
    // Feel free to change or delete any of the code you see in this editor!
    var width = 960;
    var height = 500;
    var radius = 5;
    var colors =d3.scaleOrdinal(d3.schemeCategory10);
    var drag = d3.drag()
        .on('start', function() {
        if(!d3.event.active){
          simulations.alphaTarget(0.35).restart();
        }
      })
        .on('drag', function(){
        d3.event.subject.fx = d3.event.x;
        d3.event.subject.fy = d3.event.y;
      })
        .on('end', function(){
        simulations.alphaTarget(0);
        d3.event.subject.fx = null;
        de.event.subject.fy = null;
      });
    var svg = d3.select("body").append("svg")
      .attr("width", width)
      .attr("height", height);
​
    d3.json('miserables.json', function(err, data){
//       console.log(data.links);
      //position node with their group
      var perRow = 2;
      data.nodes.forEach(function(node){
        node.focusX = (node.group % perRow)* 100;
        node.focusY = Math.floor(node.group/ perRow) * 100;
      });
       data.links.forEach(function(link) {
        link.source = data.nodes.find(function(node) {return node.id === link.source});
        link.target = data.nodes.find(function(node) {return node.id === link.target});
      });
      
      // one tick it's one iteration
      var simulations = d3.forceSimulation(data.nodes)
        .force('center', d3.forceCenter(width/2, height/2))
        .force('collide', d3.forceCollide(radius + 1))
//              .force('attraction', d3.forceManyBody().strength(100).distanceMin(150))
//          .force('repulsion', d3.forceManyBody().strength(-100).distanceMax(150))
        .force('x', d3.forceX().x(function(d){
          return d.focusX
        }))
        .force('y', d3.forceY().y(function(d){
                      return d.focusY     }))
//          .force('links', d3.forceLink(data.links)
//                .id(function(d){return d.id})
//                .strength(function(d){})
              
                                                
                                                    
        .on('tick', ticked);
      //create circle for each node, there's x and y got calculated each tick
       var links = svg.selectAll('line')
        .data(data.links, function(d){return d.source.id + ',' + d.target.id})
        .enter().append('line')
        .attr('stroke', '#ccc');
      
      var circles = svg.selectAll('circle')
        .data(data.nodes, function(d){return d.id})
        .enter().append('circle')
        .attr('r', radius)
        .attr('fill', function(d){return colors(d.group)})
        .call(drag)
     
      
      
      function ticked() {
        circles
          .attr('cx', function(d) {return d.x})
            .attr('cy', function(d) {return d.y});
        
        links.attr('x1', function(d) {return d.source.x})
            .attr('x2', function(d){return d.target.x})
            .attr('y1', function(d) {return d.source.y})
            .attr('y2', function(d){return d.target.y})
        
      }
      
    })
  </script>
</body>
​
    