Brush Handles d3v4 [UNLISTED]

Please don't use this version and refer to mbostock's original block: Brush Handles (now in d3v4).

See issue #14.

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

svg {
  font: 10px sans-serif;
}

circle {
  -webkit-transition: fill-opacity 250ms linear;
}

.selecting circle {
  fill-opacity: .2;
}

.selecting circle.selected {
  stroke: #f00;
}

.resize {
  fill: #666;
  fill-opacity: .8;
  stroke: #000;
  stroke-width: 1.5px;
}

.axis path, .axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.brush .extent {
  fill-opacity: .125;
  shape-rendering: crispEdges;
}

</style>
<body>
<script src="//d3js.org/d3.v4.js"></script>
<script>

var data = d3.range(800).map(Math.random);

var margin = {top: 194, right: 50, bottom: 214, left: 50},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var x = d3.scaleLinear()
    .range([0, width]);

var y = d3.randomNormal(height / 2, height / 8);

var brush = d3.brushX()
    .extent([[0, 0], [width, height]])
    .on("start", brushstart)
    .on("brush", brushmove)
    .on("end", brushend)
    .handleSize(height);

var arc = d3.arc()
    .outerRadius(height / 2)
    .innerRadius(0)
    .startAngle(0)
    .endAngle(function(d) { return d.type=="w" ? -Math.PI : Math.PI; });

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .call(d3.axisBottom().scale(x));

var circle = svg.append("g").selectAll("circle")
    .data(data)
  .enter().append("circle")
    .attr("transform", function(d) { return "translate(" + x(d) + "," + y() + ")"; })
    .attr("r", 3.5);

var brushg = svg.append("g")
    .attr("class", "brush")
    .call(brush);

brushg.call(brush.move, [x(0.3), x(0.5)]);
  
brushg.selectAll(".resize")
    .data([{type:"w"}, {type:"e"}])
    .enter()
    .append("path")
    .attr("class","resize");

brushstart();
brushmove();

function brushstart() {
  svg.classed("selecting", true);
  brushg.selectAll('.resize')
  .attr('d', arc)
}

function brushmove() {
  var p = d3.brushSelection(brushg.node()),
      s = p.map(x.invert);

brushg.selectAll('.resize')
     .attr('transform', function(d,i){ return 'translate(' + [p[i], height/2] + ')';});

circle.classed("selected", function(d) { return s[0] <= d && d <= s[1]; });
  
}

function brushend() {
  svg.classed("selecting", d3.event.selection);
  if (!d3.event.selection) brushg.selectAll('.resize')
  .attr('d', null)
}

</script>

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