Two axes focus+context via brushing

An alteration to /mbostock/1667367 that adds a similar vertical zoom axes to the figure.

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

svg {
  font: 10px sans-serif;
}

path {
  fill: steelblue;
}

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

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

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

var total_width = 960,
  total_height = 400,
	margin = {top: 10, right: 10, bottom: total_height*.2, left: 120},
    bottompanelmargin = {top: total_height - margin.bottom + 30, right: margin.right, bottom: 20, left: margin.left},
	leftpanelmargin = {top: margin.top, right: margin.left-40, bottom: margin.bottom, left: 40},
    width = total_width - margin.left - margin.right,
    height = total_height - margin.top - margin.bottom,
    bottompanelheight = total_height - bottompanelmargin.top - bottompanelmargin.bottom,
	leftpanelwidth = leftpanelmargin.right - leftpanelmargin.left;

var parseDate = d3.time.format("%b %Y").parse;

var x = d3.time.scale().range([0, width]),
    bottompanelx = d3.time.scale().range([0, width]),
    leftpanelx = d3.scale.linear().range([0, leftpanelwidth]),
    y = d3.scale.linear().range([height, 0]),
    bottompanely = d3.scale.linear().range([bottompanelheight, 0]),
    leftpanely = d3.scale.linear().range([height, 0]);

var xAxis = d3.svg.axis().scale(x).orient("bottom"),
    bottompanelxAxis = d3.svg.axis().scale(bottompanelx).orient("bottom"),
    yAxis = d3.svg.axis().scale(y).orient("left"),
    leftpanelyAxis = d3.svg.axis().scale(leftpanely).orient("left");

var brushx = d3.svg.brush()
    .x(bottompanelx)
    .on("brush", brushedx);

var brushy = d3.svg.brush()
    .y(leftpanely)
    .on("brush", brushedy);

var area = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y0(height)
    .y1(function(d) { return y(d.price); });

var bottompanelarea = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return bottompanelx(d.date); })
    .y0(bottompanelheight)
    .y1(function(d) { return bottompanely(d.price); });

var leftpanelarea = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return leftpanelx(d.date); })
    .y0(height)
    .y1(function(d) { return leftpanely(d.price); });

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

svg.append("defs").append("clipPath")
    .attr("id", "clip")
  .append("rect")
    .attr("width", width)
    .attr("height", height);

var focus = svg.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var leftpanelcontext = svg.append("g")
    .attr("transform", "translate(" + leftpanelmargin.left + "," + leftpanelmargin.top + ")");

var bottompanelcontext = svg.append("g")
    .attr("transform", "translate(" + bottompanelmargin.left + "," + bottompanelmargin.top + ")");

d3.csv("sp500.csv", function(error, data) {

data.forEach(function(d) {
    d.date = parseDate(d.date);
    d.price = +d.price;
  });

x.domain(d3.extent(data.map(function(d) { return d.date; })));
  y.domain([0, d3.max(data.map(function(d) { return d.price; }))]);
  bottompanelx.domain(x.domain());
  bottompanely.domain(y.domain());
  leftpanelx.domain(x.domain());
  leftpanely.domain(y.domain());

focus.append("path")
      .datum(data)
      .attr("clip-path", "url(#clip)")
      .attr("d", area);

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

focus.append("g")
      .attr("class", "y axis")
      .call(yAxis);

leftpanelcontext.append("path")
      .datum(data)
      .attr("d", leftpanelarea);

bottompanelcontext.append("path")
      .datum(data)
      .attr("d", bottompanelarea);
 
  bottompanelcontext.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + bottompanelheight + ")")
      .call(bottompanelxAxis);

leftpanelcontext.append("g")
      .attr("class", "y axis")
      .attr("transform", "translate(" - leftpanelwidth + ", 0 )")
      .call(leftpanelyAxis);

bottompanelcontext.append("g")
      .attr("class", "x brush")
      .call(brushx)
    .selectAll("rect")
      .attr("y", -6) // 6 goes along with 7 below for shifting.
      .attr("height", bottompanelheight + 7);

leftpanelcontext.append("g")
      .attr("class", "y brush")
      .call(brushy)
    .selectAll("rect")
      .attr("width", leftpanelwidth);
});

function brushedx() {
  x.domain(brushx.empty() ? bottompanelx.domain() : brushx.extent());
  focus.select("path").attr("d", area);
  focus.select(".x.axis").call(xAxis);
}

function brushedy() {
  y.domain(brushy.empty() ? leftpanely.domain() : brushy.extent());
  focus.select("path").attr("d", area);
  focus.select(".y.axis").call(yAxis);
}

</script>

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

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