D3 Force Simulation

forked from john-guerra's block: D3 Force Simulation

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

<body>
  <h1>Force Directed layout</h1>
  <svg 
    width=400 
    height=400
    id="network"></svg>
  
    <script src="https://d3js.org/d3.v4.min.js"></script>
  <script>
    // Copy drag from: https://bl.ocks.org/mbostock/4062045
    
    let svg = d3.select("#network"),
        width = +svg.attr("width"),
        height = + svg.attr("height"),
        N = 100;
    
    let nodes = d3.range(N).map(() => {
      return {
//         x: Math.random()*width,
//         y: Math.random()*height
      };		      
    });
    
    let links = d3.range(N*3).map(() => {
      return {
        source:Math.floor(Math.random()*N),
        target:Math.floor(Math.random()*N)
      }
    });
    console.log(width, height);
    
    let simulation = d3.forceSimulation(nodes)
    	.force("center", d3.forceCenter(width/2, height/2))
    	.force("charge", d3.forceManyBody().strength(-5))
    	.force("link", d3.forceLink(links)
            	.distance(50))
      .force("collide",d3.forceCollide(20))
    
    	.on("tick", ticked);
    	
    
    console.log("nodes", nodes);
    console.log("links", links);    
    
    
    let sellinks = svg.selectAll(".link")
    	.data(links)
    	.enter()
    	.append("line")
    	.attr("class", "link")
      .style("stroke", "#aaa")
      .style("opacity", 0.9)
    
    let selnodes = svg.selectAll(".node")
    	.data(nodes)
    	.enter()
    	.append("circle")
    	.attr("class", "node")
      .style("fill", "steelblue")
      .attr("r", 16)
      .call(d3.drag()
          .on("start", dragstarted)
          .on("drag", dragged)
          .on("end", dragended));

function ticked() {
			sellinks.attr("x1", (l) => l.source.x)
        .attr("y1", (l) => l.source.y)
        .attr("x2", (l) => l.target.x)
        .attr("y2", (l) => l.target.y);

selnodes.attr("cx", (d) => d.x)
	      .attr("cy", (d) => d.y);
     
//      console.log("ticked!");

}
    
    function dragstarted(d) {
  if (!d3.event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}

function dragged(d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}

function dragended(d) {
  if (!d3.event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}

</script>
</body>

https://d3js.org/d3.v4.min.js