Coordinating a brush and a donut

Update a donut chart extent based on a dragged brush extent

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

.axis path {
  display: none;
}

.axis line {
  display: none;
}

.grid-background {
  fill: #e2e3e3;
}

.grid line,
.grid path {
  display: none;
}

path.update {
  shape-rendering: crispEdges;
}

.brush .extent {
  fill:#3300ff;
  fill-opacity: .125;
  shape-rendering: crispEdges;
}

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

var margin = {top: 20, right: 40, bottom: 20, left: 40},
    width = 500 - margin.left - margin.right,
    height = 400 - margin.top - margin.bottom;
    radius = Math.min(width, height) / 2;
//brush stuff:
var x = d3.scale.linear()
    .domain([0,100])
    .range([0, width]);

var brush = d3.svg.brush()
    .x(x)
    .extent([0,40])
    .on("brush", brushend);

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("rect")
    .attr("class", "grid-background")
    .attr("width", width)
    .attr("height", height);

svg.append("g")
    .attr("class", "x grid")
    .attr("transform", "translate(0," + height + ")");

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

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

gBrush.selectAll("rect")
    .attr("height", height);

gBrush.selectAll("rect")
    .style("pointer-events","none")
    .attr("y", -1)
    .attr("height", height);
gBrush.selectAll(".resize.e")
  .append("image")
    .attr("width", 35)
    .attr("height",35)
    .attr("y",height/2.1)
    .attr("x",-17)
    .attr("xlink:href",'arrow_right.png');

// end brush stuff

// donut stuff:

var color = d3.scale.category20();

var pie = d3.layout.pie()
    .sort(null);

var arc = d3.svg.arc()
    .innerRadius(radius - 100)
    .outerRadius(radius - 60);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
    .append("g")
    .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");

function brushend() {
  var path = svg.selectAll("path")
    .data(pie([brush.extent()[1],100 - brush.extent()[1]]))
  
  path.attr("class","update");

path.enter().append("path")
    .attr("fill", function(d, i) { return color(i); })
    .attr("d", arc);

path.exit().remove("path");
};

brushend();

</script>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js