UK General Election 2017 Transfer of Seats Sankey Chart (D3 v4)

.block

license: mit
height: 1000

.gitignore

node_modules/

README.md

This alluvial flow, or Sankey, graph is an attempt to show the transfer of numbers of seats from those UK political parties who won them in 2015 to those who won them in the UK general election on 8th June 2017.

Unless you are already on Blocks looking at this, you can see this code in action on the Blocks page for this visualisation.

Local usage

If downloading as a local repo, viewing the HTML file directly can be problematic unless you enable CORS (cross-origin resource sharing). This is because the data is pulled in from raw.csvand if you view the HTML file directly without CORS enabled the browser is prevented from getting the data file even though it's in the same folder.

To get around this, I've specified http-server as a devDependency.

You can use either npm start or http-server to start up a simple local server and then go its address (e.g., localhost:8080) in your browser directly to see the file.

Local development

If developing this visualisation for yourself, you should know that the Node packages are included as dependencies in package.json.

You can use npm install as usual to get these.

Amend index.html and main.js to make changes.

Because the visualisation was developed with the browser and specifically Blocks, in mind, each time you update main.js you will need to run

browserify main.js > bundle.js

This updates the bundle.js file that pulls together the main code and any package dependencies for the browser.

bundle.js

(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
/*

	This file needs to be compiled with Browserify to `bundle.js` in order that the visualisation can be displayed in the browser.

*/
var d3 = require("d3")
d3.sankey = require("d3-sankey").sankey
d3.sankeyLinkHorizontal = require("d3-sankey").sankeyLinkHorizontal

var margin = {top: 10, right: 10, bottom: 10, left: 10}
var width = 960 - margin.left - margin.right
var height = 1000 - margin.top - margin.bottom

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})`)

var format = (d) => `${d} seats`
var color = d3.scaleOrdinal(d3.schemeCategory10)

sankey = d3.sankey()
    .nodeWidth(15)
    .nodePadding(10)
    .size([width, height])

d3.csv("raw.csv", function (error, data) {
    if (error) throw error

    var blocs = data.reduce((p, c) => {
        p[`${c["2015"]} (2015)`] = p[`${c["2015"]} (2015)`] + 1 || 1
        p[`${c["2017"]} (2017)`] = p[`${c["2017"]} (2017)`] + 1 || 1
        return p
    }, {})

    var pairs = data.reduce((p, c) => {
        p[`${c["2015"]} (2015)|${c["2017"]} (2017)`] = p[`${c["2015"]} (2015)|${c["2017"]} (2017)`] + 1 || 1
        return p
    }, {})

    var diffs = Object.keys(pairs)
        .map(p => ({
            source: p.replace(/\|.*/, ""),
            target: p.replace(/.*\|/, ""),
            value: pairs[p]
        }))

    var nodes = Object.keys(blocs)
        .map(k => ({
            "name": k,
            "value": blocs[k]
        }))
        .sort((a, b) => b.value - a.value)

    graph = {
        "nodes" : nodes,
        "links" : diffs.map(d => ({
                source: nodes.map(x => x.name).indexOf(d.source),
                target: nodes.map(x => x.name).indexOf(d.target),
                value: d.value
            }))
    }

    function dragmove(d) {
        d3.select(this)
            .attr("transform", `translate(${d.x0}, ${d.y0 = Math.max(
                    0, Math.min(height - (d.y1 - d.y0), d.y0 + d3.event.dy))})`)
        sankey.update(graph)
        link.attr("d", path)
    }

    sankey(graph)
    var path = d3.sankeyLinkHorizontal()

    var link = svg.append("g").selectAll(".link")
            .data(graph.links)
        .enter().append("path")
            .attr("class", "link")
            .attr("fill", "none")
            .attr("stroke", "#000")
            .attr("stroke-opacity", 0.2)
            .attr("d", path)
            .attr("stroke-width", d => Math.max(1, d.width))

    link.append("title")
        .text(d => `${d.source.name}, → ${d.target.name}\n${format(d.value)}`)

    var node = svg.append("g").selectAll(".node")
            .data(graph.nodes)
        .enter().append("g")
            .attr("font-family", "sans-serif")
            .attr("font-size", 10)
            .attr("class", "node")
            .attr("transform", d => `translate(${d.x0}, ${d.y0})`)
            .call(d3.drag()
                .subject(d => d)
                .on("drag", dragmove)
            )

    node.append("rect")
        .attr("height", d => d.y1 - d.y0)
        .attr("width", d => d.x1 - d.x0)
        .attr("fill", function(d) {
            return color(d.name.replace(/ .*/, ""))
        })
        .attr("stroke", "#000")
    .append("title")
        .text(d => `${d.name}\n${format(d.value)}`)

    node.append("text")
        .attr("x", -6)
        .attr("y", d => (d.y1 - d.y0) / 2)
        .attr("dy", "0.35em")
        .attr("text-anchor", "end")
        .text(d => d.name)
    .filter(d => d.x0 < width / 2)
        .attr("x", d => 6 + sankey.nodeWidth())
        .attr("text-anchor", "start")

})

},{"d3":7,"d3-sankey":5}],2:[function(require,module,exports){
// https://d3js.org/d3-array/ Version 1.2.0. Copyright 2017 Mike Bostock.
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
	typeof define === 'function' && define.amd ? define(['exports'], factory) :
	(factory((global.d3 = global.d3 || {})));
}(this, (function (exports) { 'use strict';

var ascending = function(a, b) {
  return a < b ? -1 : a > b ? 1 : a >= b ? 0 : NaN;
};

var bisector = function(compare) {
  if (compare.length === 1) compare = ascendingComparator(compare);
  return {
    left: function(a, x, lo, hi) {
      if (lo == null) lo = 0;
      if (hi == null) hi = a.length;
      while (lo < hi) {
        var mid = lo + hi >>> 1;
        if (compare(a[mid], x) < 0) lo = mid + 1;
        else hi = mid;
      }
      return lo;
    },
    right: function(a, x, lo, hi) {
      if (lo == null) lo = 0;
      if (hi == null) hi = a.length;
      while (lo < hi) {
        var mid = lo + hi >>> 1;
        if (compare(a[mid], x) > 0) hi = mid;
        else lo = mid + 1;
      }
      return lo;
    }
  };
};

function ascendingComparator(f) {
  return function(d, x) {
    return ascending(f(d), x);
  };
}

var ascendingBisect = bisector(ascending);
var bisectRight = ascendingBisect.right;
var bisectLeft = ascendingBisect.left;

var pairs = function(array, f) {
  if (f == null) f = pair;
  var i = 0, n = array.length - 1, p = array[0], pairs = new Array(n < 0 ? 0 : n);
  while (i < n) pairs[i] = f(p, p = array[++i]);
  return pairs;
};

function pair(a, b) {
  return [a, b];
}

var cross = function(values0, values1, reduce) {
  var n0 = values0.length,
      n1 = values1.length,
      values = new Array(n0 * n1),
      i0,
      i1,
      i,
      value0;

  if (reduce == null) reduce = pair;

  for (i0 = i = 0; i0 < n0; ++i0) {
    for (value0 = values0[i0], i1 = 0; i1 < n1; ++i1, ++i) {
      values[i] = reduce(value0, values1[i1]);
    }
  }

  return values;
};

var descending = function(a, b) {
  return b < a ? -1 : b > a ? 1 : b >= a ? 0 : NaN;
};

var number = function(x) {
  return x === null ? NaN : +x;
};

var variance = function(values, valueof) {
  var n = values.length,
      m = 0,
      i = -1,
      mean = 0,
      value,
      delta,
      sum = 0;

  if (valueof == null) {
    while (++i < n) {
      if (!isNaN(value = number(values[i]))) {
        delta = value - mean;
        mean += delta / ++m;
        sum += delta * (value - mean);
      }
    }
  }

  else {
    while (++i < n) {
      if (!isNaN(value = number(valueof(values[i], i, values)))) {
        delta = value - mean;
        mean += delta / ++m;
        sum += delta * (value - mean);
      }
    }
  }

  if (m > 1) return sum / (m - 1);
};

var deviation = function(array, f) {
  var v = variance(array, f);
  return v ? Math.sqrt(v) : v;
};

var extent = function(values, valueof) {
  var n = values.length,
      i = -1,
      value,
      min,
      max;

  if (valueof == null) {
    while (++i < n) { // Find the first comparable value.
      if ((value = values[i]) != null && value >= value) {
        min = max = value;
        while (++i < n) { // Compare the remaining values.
          if ((value = values[i]) != null) {
            if (min > value) min = value;
            if (max < value) max = value;
          }
        }
      }
    }
  }

  else {
    while (++i < n) { // Find the first comparable value.
      if ((value = valueof(values[i], i, values)) != null && value >= value) {
        min = max = value;
        while (++i < n) { // Compare the remaining values.
          if ((value = valueof(values[i], i, values)) != null) {
            if (min > value) min = value;
            if (max < value) max = value;
          }
        }
      }
    }
  }

  return [min, max];
};

var array = Array.prototype;

var slice = array.slice;
var map = array.map;

var constant = function(x) {
  return function() {
    return x;
  };
};

var identity = function(x) {
  return x;
};

var range = function(start, stop, step) {
  start = +start, stop = +stop, step = (n = arguments.length) < 2 ? (stop = start, start = 0, 1) : n < 3 ? 1 : +step;

  var i = -1,
      n = Math.max(0, Math.ceil((stop - start) / step)) | 0,
      range = new Array(n);

  while (++i < n) {
    range[i] = start + i * step;
  }

  return range;
};

var e10 = Math.sqrt(50);
var e5 = Math.sqrt(10);
var e2 = Math.sqrt(2);

var ticks = function(start, stop, count) {
  var reverse = stop < start,
      i = -1,
      n,
      ticks,
      step;

  if (reverse) n = start, start = stop, stop = n;

  if ((step = tickIncrement(start, stop, count)) === 0 || !isFinite(step)) return [];

  if (step > 0) {
    start = Math.ceil(start / step);
    stop = Math.floor(stop / step);
    ticks = new Array(n = Math.ceil(stop - start + 1));
    while (++i < n) ticks[i] = (start + i) * step;
  } else {
    start = Math.floor(start * step);
    stop = Math.ceil(stop * step);
    ticks = new Array(n = Math.ceil(start - stop + 1));
    while (++i < n) ticks[i] = (start - i) / step;
  }

  if (reverse) ticks.reverse();

  return ticks;
};

function tickIncrement(start, stop, count) {
  var step = (stop - start) / Math.max(0, count),
      power = Math.floor(Math.log(step) / Math.LN10),
      error = step / Math.pow(10, power);
  return power >= 0
      ? (error >= e10 ? 10 : error >= e5 ? 5 : error >= e2 ? 2 : 1) * Math.pow(10, power)
      : -Math.pow(10, -power) / (error >= e10 ? 10 : error >= e5 ? 5 : error >= e2 ? 2 : 1);
}

function tickStep(start, stop, count) {
  var step0 = Math.abs(stop - start) / Math.max(0, count),
      step1 = Math.pow(10, Math.floor(Math.log(step0) / Math.LN10)),
      error = step0 / step1;
  if (error >= e10) step1 *= 10;
  else if (error >= e5) step1 *= 5;
  else if (error >= e2) step1 *= 2;
  return stop < start ? -step1 : step1;
}

var sturges = function(values) {
  return Math.ceil(Math.log(values.length) / Math.LN2) + 1;
};

var histogram = function() {
  var value = identity,
      domain = extent,
      threshold = sturges;

  function histogram(data) {
    var i,
        n = data.length,
        x,
        values = new Array(n);

    for (i = 0; i < n; ++i) {
      values[i] = value(data[i], i, data);
    }

    var xz = domain(values),
        x0 = xz[0],
        x1 = xz[1],
        tz = threshold(values, x0, x1);

    // Convert number of thresholds into uniform thresholds.
    if (!Array.isArray(tz)) {
      tz = tickStep(x0, x1, tz);
      tz = range(Math.ceil(x0 / tz) * tz, Math.floor(x1 / tz) * tz, tz); // exclusive
    }

    // Remove any thresholds outside the domain.
    var m = tz.length;
    while (tz[0] <= x0) tz.shift(), --m;
    while (tz[m - 1] > x1) tz.pop(), --m;

    var bins = new Array(m + 1),
        bin;

    // Initialize bins.
    for (i = 0; i <= m; ++i) {
      bin = bins[i] = [];
      bin.x0 = i > 0 ? tz[i - 1] : x0;
      bin.x1 = i < m ? tz[i] : x1;
    }

    // Assign data to bins by value, ignoring any outside the domain.
    for (i = 0; i < n; ++i) {
      x = values[i];
      if (x0 <= x && x <= x1) {
        bins[bisectRight(tz, x, 0, m)].push(data[i]);
      }
    }

    return bins;
  }

  histogram.value = function(_) {
    return arguments.length ? (value = typeof _ === "function" ? _ : constant(_), histogram) : value;
  };

  histogram.domain = function(_) {
    return arguments.length ? (domain = typeof _ === "function" ? _ : constant([_[0], _[1]]), histogram) : domain;
  };

  histogram.thresholds = function(_) {
    return arguments.length ? (threshold = typeof _ === "function" ? _ : Array.isArray(_) ? constant(slice.call(_)) : constant(_), histogram) : threshold;
  };

  return histogram;
};

var quantile = function(values, p, valueof) {
  if (valueof == null) valueof = number;
  if (!(n = values.length)) return;
  if ((p = +p) <= 0 || n < 2) return +valueof(values[0], 0, values);
  if (p >= 1) return +valueof(values[n - 1], n - 1, values);
  var n,
      i = (n - 1) * p,
      i0 = Math.floor(i),
      value0 = +valueof(values[i0], i0, values),
      value1 = +valueof(values[i0 + 1], i0 + 1, values);
  return value0 + (value1 - value0) * (i - i0);
};

var freedmanDiaconis = function(values, min, max) {
  values = map.call(values, number).sort(ascending);
  return Math.ceil((max - min) / (2 * (quantile(values, 0.75) - quantile(values, 0.25)) * Math.pow(values.length, -1 / 3)));
};

var scott = function(values, min, max) {
  return Math.ceil((max - min) / (3.5 * deviation(values) * Math.pow(values.length, -1 / 3)));
};

var max = function(values, valueof) {
  var n = values.length,
      i = -1,
      value,
      max;

  if (valueof == null) {
    while (++i < n) { // Find the first comparable value.
      if ((value = values[i]) != null && value >= value) {
        max = value;
        while (++i < n) { // Compare the remaining values.
          if ((value = values[i]) != null && value > max) {
            max = value;
          }
        }
      }
    }
  }

  else {
    while (++i < n) { // Find the first comparable value.
      if ((value = valueof(values[i], i, values)) != null && value >= value) {
        max = value;
        while (++i < n) { // Compare the remaining values.
          if ((value = valueof(values[i], i, values)) != null && value > max) {
            max = value;
          }
        }
      }
    }
  }

  return max;
};

var mean = function(values, valueof) {
  var n = values.length,
      m = n,
      i = -1,
      value,
      sum = 0;

  if (valueof == null) {
    while (++i < n) {
      if (!isNaN(value = number(values[i]))) sum += value;
      else --m;
    }
  }

  else {
    while (++i < n) {
      if (!isNaN(value = number(valueof(values[i], i, values)))) sum += value;
      else --m;
    }
  }

  if (m) return sum / m;
};

var median = function(values, valueof) {
  var n = values.length,
      i = -1,
      value,
      numbers = [];

  if (valueof == null) {
    while (++i < n) {
      if (!isNaN(value = number(values[i]))) {
        numbers.push(value);
      }
    }
  }

  else {
    while (++i < n) {
      if (!isNaN(value = number(valueof(values[i], i, values)))) {
        numbers.push(value);
      }
    }
  }

  return quantile(numbers.sort(ascending), 0.5);
};

var merge = function(arrays) {
  var n = arrays.length,
      m,
      i = -1,
      j = 0,
      merged,
      array;

  while (++i < n) j += arrays[i].length;
  merged = new Array(j);

  while (--n >= 0) {
    array = arrays[n];
    m = array.length;
    while (--m >= 0) {
      merged[--j] = array[m];
    }
  }

  return merged;
};

var min = function(values, valueof) {
  var n = values.length,
      i = -1,
      value,
      min;

  if (valueof == null) {
    while (++i < n) { // Find the first comparable value.
      if ((value = values[i]) != null && value >= value) {
        min = value;
        while (++i < n) { // Compare the remaining values.
          if ((value = values[i]) != null && min > value) {
            min = value;
          }
        }
      }
    }
  }

  else {
    while (++i < n) { // Find the first comparable value.
      if ((value = valueof(values[i], i, values)) != null && value >= value) {
        min = value;
        while (++i < n) { // Compare the remaining values.
          if ((value = valueof(values[i], i, values)) != null && min > value) {
            min = value;
          }
        }
      }
    }
  }

  return min;
};

var permute = function(array, indexes) {
  var i = indexes.length, permutes = new Array(i);
  while (i--) permutes[i] = array[indexes[i]];
  return permutes;
};

var scan = function(values, compare) {
  if (!(n = values.length)) return;
  var n,
      i = 0,
      j = 0,
      xi,
      xj = values[j];

  if (compare == null) compare = ascending;

  while (++i < n) {
    if (compare(xi = values[i], xj) < 0 || compare(xj, xj) !== 0) {
      xj = xi, j = i;
    }
  }

  if (compare(xj, xj) === 0) return j;
};

var shuffle = function(array, i0, i1) {
  var m = (i1 == null ? array.length : i1) - (i0 = i0 == null ? 0 : +i0),
      t,
      i;

  while (m) {
    i = Math.random() * m-- | 0;
    t = array[m + i0];
    array[m + i0] = array[i + i0];
    array[i + i0] = t;
  }

  return array;
};

var sum = function(values, valueof) {
  var n = values.length,
      i = -1,
      value,
      sum = 0;

  if (valueof == null) {
    while (++i < n) {
      if (value = +values[i]) sum += value; // Note: zero and null are equivalent.
    }
  }

  else {
    while (++i < n) {
      if (value = +valueof(values[i], i, values)) sum += value;
    }
  }

  return sum;
};

var transpose = function(matrix) {
  if (!(n = matrix.length)) return [];
  for (var i = -1, m = min(matrix, length), transpose = new Array(m); ++i < m;) {
    for (var j = -1, n, row = transpose[i] = new Array(n); ++j < n;) {
      row[j] = matrix[j][i];
    }
  }
  return transpose;
};

function length(d) {
  return d.length;
}

var zip = function() {
  return transpose(arguments);
};

exports.bisect = bisectRight;
exports.bisectRight = bisectRight;
exports.bisectLeft = bisectLeft;
exports.ascending = ascending;
exports.bisector = bisector;
exports.cross = cross;
exports.descending = descending;
exports.deviation = deviation;
exports.extent = extent;
exports.histogram = histogram;
exports.thresholdFreedmanDiaconis = freedmanDiaconis;
exports.thresholdScott = scott;
exports.thresholdSturges = sturges;
exports.max = max;
exports.mean = mean;
exports.median = median;
exports.merge = merge;
exports.min = min;
exports.pairs = pairs;
exports.permute = permute;
exports.quantile = quantile;
exports.range = range;
exports.scan = scan;
exports.shuffle = shuffle;
exports.sum = sum;
exports.ticks = ticks;
exports.tickIncrement = tickIncrement;
exports.tickStep = tickStep;
exports.transpose = transpose;
exports.variance = variance;
exports.zip = zip;

Object.defineProperty(exports, '__esModule', { value: true });

})));

},{}],3:[function(require,module,exports){
// https://d3js.org/d3-collection/ Version 1.0.3. Copyright 2017 Mike Bostock.
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
	typeof define === 'function' && define.amd ? define(['exports'], factory) :
	(factory((global.d3 = global.d3 || {})));
}(this, (function (exports) { 'use strict';

var prefix = "$";

function Map() {}

Map.prototype = map.prototype = {
  constructor: Map,
  has: function(key) {
    return (prefix + key) in this;
  },
  get: function(key) {
    return this[prefix + key];
  },
  set: function(key, value) {
    this[prefix + key] = value;
    return this;
  },
  remove: function(key) {
    var property = prefix + key;
    return property in this && delete this[property];
  },
  clear: function() {
    for (var property in this) if (property[0] === prefix) delete this[property];
  },
  keys: function() {
    var keys = [];
    for (var property in this) if (property[0] === prefix) keys.push(property.slice(1));
    return keys;
  },
  values: function() {
    var values = [];
    for (var property in this) if (property[0] === prefix) values.push(this[property]);
    return values;
  },
  entries: function() {
    var entries = [];
    for (var property in this) if (property[0] === prefix) entries.push({key: property.slice(1), value: this[property]});
    return entries;
  },
  size: function() {
    var size = 0;
    for (var property in this) if (property[0] === prefix) ++size;
    return size;
  },
  empty: function() {
    for (var property in this) if (property[0] === prefix) return false;
    return true;
  },
  each: function(f) {
    for (var property in this) if (property[0] === prefix) f(this[property], property.slice(1), this);
  }
};

function map(object, f) {
  var map = new Map;

  // Copy constructor.
  if (object instanceof Map) object.each(function(value, key) { map.set(key, value); });

  // Index array by numeric index or specified key function.
  else if (Array.isArray(object)) {
    var i = -1,
        n = object.length,
        o;

    if (f == null) while (++i < n) map.set(i, object[i]);
    else while (++i < n) map.set(f(o = object[i], i, object), o);
  }

  // Convert object to map.
  else if (object) for (var key in object) map.set(key, object[key]);

  return map;
}

var nest = function() {
  var keys = [],
      sortKeys = [],
      sortValues,
      rollup,
      nest;

  function apply(array, depth, createResult, setResult) {
    if (depth >= keys.length) return rollup != null
        ? rollup(array) : (sortValues != null
        ? array.sort(sortValues)
        : array);

    var i = -1,
        n = array.length,
        key = keys[depth++],
        keyValue,
        value,
        valuesByKey = map(),
        values,
        result = createResult();

    while (++i < n) {
      if (values = valuesByKey.get(keyValue = key(value = array[i]) + "")) {
        values.push(value);
      } else {
        valuesByKey.set(keyValue, [value]);
      }
    }

    valuesByKey.each(function(values, key) {
      setResult(result, key, apply(values, depth, createResult, setResult));
    });

    return result;
  }

  function entries(map$$1, depth) {
    if (++depth > keys.length) return map$$1;
    var array, sortKey = sortKeys[depth - 1];
    if (rollup != null && depth >= keys.length) array = map$$1.entries();
    else array = [], map$$1.each(function(v, k) { array.push({key: k, values: entries(v, depth)}); });
    return sortKey != null ? array.sort(function(a, b) { return sortKey(a.key, b.key); }) : array;
  }

  return nest = {
    object: function(array) { return apply(array, 0, createObject, setObject); },
    map: function(array) { return apply(array, 0, createMap, setMap); },
    entries: function(array) { return entries(apply(array, 0, createMap, setMap), 0); },
    key: function(d) { keys.push(d); return nest; },
    sortKeys: function(order) { sortKeys[keys.length - 1] = order; return nest; },
    sortValues: function(order) { sortValues = order; return nest; },
    rollup: function(f) { rollup = f; return nest; }
  };
};

function createObject() {
  return {};
}

function setObject(object, key, value) {
  object[key] = value;
}

function createMap() {
  return map();
}

function setMap(map$$1, key, value) {
  map$$1.set(key, value);
}

function Set() {}

var proto = map.prototype;

Set.prototype = set.prototype = {
  constructor: Set,
  has: proto.has,
  add: function(value) {
    value += "";
    this[prefix + value] = value;
    return this;
  },
  remove: proto.remove,
  clear: proto.clear,
  values: proto.keys,
  size: proto.size,
  empty: proto.empty,
  each: proto.each
};

function set(object, f) {
  var set = new Set;

  // Copy constructor.
  if (object instanceof Set) object.each(function(value) { set.add(value); });

  // Otherwise, assume it’s an array.
  else if (object) {
    var i = -1, n = object.length;
    if (f == null) while (++i < n) set.add(object[i]);
    else while (++i < n) set.add(f(object[i], i, object));
  }

  return set;
}

var keys = function(map) {
  var keys = [];
  for (var key in map) keys.push(key);
  return keys;
};

var values = function(map) {
  var values = [];
  for (var key in map) values.push(map[key]);
  return values;
};

var entries = function(map) {
  var entries = [];
  for (var key in map) entries.push({key: key, value: map[key]});
  return entries;
};

exports.nest = nest;
exports.set = set;
exports.map = map;
exports.keys = keys;
exports.values = values;
exports.entries = entries;

Object.defineProperty(exports, '__esModule', { value: true });

})));

},{}],4:[function(require,module,exports){
// https://d3js.org/d3-path/ Version 1.0.5. Copyright 2017 Mike Bostock.
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
	typeof define === 'function' && define.amd ? define(['exports'], factory) :
	(factory((global.d3 = global.d3 || {})));
}(this, (function (exports) { 'use strict';

var pi = Math.PI;
var tau = 2 * pi;
var epsilon = 1e-6;
var tauEpsilon = tau - epsilon;

function Path() {
  this._x0 = this._y0 = // start of current subpath
  this._x1 = this._y1 = null; // end of current subpath
  this._ = "";
}

function path() {
  return new Path;
}

Path.prototype = path.prototype = {
  constructor: Path,
  moveTo: function(x, y) {
    this._ += "M" + (this._x0 = this._x1 = +x) + "," + (this._y0 = this._y1 = +y);
  },
  closePath: function() {
    if (this._x1 !== null) {
      this._x1 = this._x0, this._y1 = this._y0;
      this._ += "Z";
    }
  },
  lineTo: function(x, y) {
    this._ += "L" + (this._x1 = +x) + "," + (this._y1 = +y);
  },
  quadraticCurveTo: function(x1, y1, x, y) {
    this._ += "Q" + (+x1) + "," + (+y1) + "," + (this._x1 = +x) + "," + (this._y1 = +y);
  },
  bezierCurveTo: function(x1, y1, x2, y2, x, y) {
    this._ += "C" + (+x1) + "," + (+y1) + "," + (+x2) + "," + (+y2) + "," + (this._x1 = +x) + "," + (this._y1 = +y);
  },
  arcTo: function(x1, y1, x2, y2, r) {
    x1 = +x1, y1 = +y1, x2 = +x2, y2 = +y2, r = +r;
    var x0 = this._x1,
        y0 = this._y1,
        x21 = x2 - x1,
        y21 = y2 - y1,
        x01 = x0 - x1,
        y01 = y0 - y1,
        l01_2 = x01 * x01 + y01 * y01;

    // Is the radius negative? Error.
    if (r < 0) throw new Error("negative radius: " + r);

    // Is this path empty? Move to (x1,y1).
    if (this._x1 === null) {
      this._ += "M" + (this._x1 = x1) + "," + (this._y1 = y1);
    }

    // Or, is (x1,y1) coincident with (x0,y0)? Do nothing.
    else if (!(l01_2 > epsilon)) {}

    // Or, are (x0,y0), (x1,y1) and (x2,y2) collinear?
    // Equivalently, is (x1,y1) coincident with (x2,y2)?
    // Or, is the radius zero? Line to (x1,y1).
    else if (!(Math.abs(y01 * x21 - y21 * x01) > epsilon) || !r) {
      this._ += "L" + (this._x1 = x1) + "," + (this._y1 = y1);
    }

    // Otherwise, draw an arc!
    else {
      var x20 = x2 - x0,
          y20 = y2 - y0,
          l21_2 = x21 * x21 + y21 * y21,
          l20_2 = x20 * x20 + y20 * y20,
          l21 = Math.sqrt(l21_2),
          l01 = Math.sqrt(l01_2),
          l = r * Math.tan((pi - Math.acos((l21_2 + l01_2 - l20_2) / (2 * l21 * l01))) / 2),
          t01 = l / l01,
          t21 = l / l21;

      // If the start tangent is not coincident with (x0,y0), line to.
      if (Math.abs(t01 - 1) > epsilon) {
        this._ += "L" + (x1 + t01 * x01) + "," + (y1 + t01 * y01);
      }

      this._ += "A" + r + "," + r + ",0,0," + (+(y01 * x20 > x01 * y20)) + "," + (this._x1 = x1 + t21 * x21) + "," + (this._y1 = y1 + t21 * y21);
    }
  },
  arc: function(x, y, r, a0, a1, ccw) {
    x = +x, y = +y, r = +r;
    var dx = r * Math.cos(a0),
        dy = r * Math.sin(a0),
        x0 = x + dx,
        y0 = y + dy,
        cw = 1 ^ ccw,
        da = ccw ? a0 - a1 : a1 - a0;

    // Is the radius negative? Error.
    if (r < 0) throw new Error("negative radius: " + r);

    // Is this path empty? Move to (x0,y0).
    if (this._x1 === null) {
      this._ += "M" + x0 + "," + y0;
    }

    // Or, is (x0,y0) not coincident with the previous point? Line to (x0,y0).
    else if (Math.abs(this._x1 - x0) > epsilon || Math.abs(this._y1 - y0) > epsilon) {
      this._ += "L" + x0 + "," + y0;
    }

    // Is this arc empty? We’re done.
    if (!r) return;

    // Does the angle go the wrong way? Flip the direction.
    if (da < 0) da = da % tau + tau;

    // Is this a complete circle? Draw two arcs to complete the circle.
    if (da > tauEpsilon) {
      this._ += "A" + r + "," + r + ",0,1," + cw + "," + (x - dx) + "," + (y - dy) + "A" + r + "," + r + ",0,1," + cw + "," + (this._x1 = x0) + "," + (this._y1 = y0);
    }

    // Is this arc non-empty? Draw an arc!
    else if (da > epsilon) {
      this._ += "A" + r + "," + r + ",0," + (+(da >= pi)) + "," + cw + "," + (this._x1 = x + r * Math.cos(a1)) + "," + (this._y1 = y + r * Math.sin(a1));
    }
  },
  rect: function(x, y, w, h) {
    this._ += "M" + (this._x0 = this._x1 = +x) + "," + (this._y0 = this._y1 = +y) + "h" + (+w) + "v" + (+h) + "h" + (-w) + "Z";
  },
  toString: function() {
    return this._;
  }
};

exports.path = path;

Object.defineProperty(exports, '__esModule', { value: true });

})));

},{}],5:[function(require,module,exports){
// https://github.com/d3/d3-sankey Version 0.6.0. Copyright 2017 Mike Bostock.
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('d3-array'), require('d3-collection'), require('d3-shape')) :
	typeof define === 'function' && define.amd ? define(['exports', 'd3-array', 'd3-collection', 'd3-shape'], factory) :
	(factory((global.d3 = global.d3 || {}),global.d3,global.d3,global.d3));
}(this, (function (exports,d3Array,d3Collection,d3Shape) { 'use strict';

function constant(x) {
  return function() {
    return x;
  };
}

function ascendingSourceBreadth(a, b) {
  return ascendingBreadth(a.source, b.source) || a.index - b.index;
}

function ascendingTargetBreadth(a, b) {
  return ascendingBreadth(a.target, b.target) || a.index - b.index;
}

function ascendingBreadth(a, b) {
  return a.y0 - b.y0;
}

function value(d) {
  return d.value;
}

function nodeCenter(node) {
  return (node.y0 + node.y1) / 2;
}

function weightedSource(link) {
  return nodeCenter(link.source) * link.value;
}

function weightedTarget(link) {
  return nodeCenter(link.target) * link.value;
}

function defaultNodes(graph) {
  return graph.nodes;
}

function defaultLinks(graph) {
  return graph.links;
}

var sankey = function() {
  var x0 = 0, y0 = 0, x1 = 1, y1 = 1, // extent
      dx = 24, // nodeWidth
      py = 8, // nodePadding
      nodes = defaultNodes,
      links = defaultLinks,
      iterations = 32;

  function sankey() {
    var graph = {nodes: nodes.apply(null, arguments), links: links.apply(null, arguments)};
    computeNodeLinks(graph);
    computeNodeValues(graph);
    computeNodeDepths(graph);
    computeNodeBreadths(graph, iterations);
    computeLinkBreadths(graph);
    return graph;
  }

  sankey.update = function(graph) {
    computeLinkBreadths(graph);
    return graph;
  };

  sankey.nodeWidth = function(_) {
    return arguments.length ? (dx = +_, sankey) : dx;
  };

  sankey.nodePadding = function(_) {
    return arguments.length ? (py = +_, sankey) : py;
  };

  sankey.nodes = function(_) {
    return arguments.length ? (nodes = typeof _ === "function" ? _ : constant(_), sankey) : nodes;
  };

  sankey.links = function(_) {
    return arguments.length ? (links = typeof _ === "function" ? _ : constant(_), sankey) : links;
  };

  sankey.size = function(_) {
    return arguments.length ? (x0 = y0 = 0, x1 = +_[0], y1 = +_[1], sankey) : [x1 - x0, y1 - y0];
  };

  sankey.extent = function(_) {
    return arguments.length ? (x0 = +_[0][0], x1 = +_[1][0], y0 = +_[0][1], y1 = +_[1][1], sankey) : [[x0, y0], [x1, y1]];
  };

  sankey.iterations = function(_) {
    return arguments.length ? (iterations = +_, sankey) : iterations;
  };

  // Populate the sourceLinks and targetLinks for each node.
  // Also, if the source and target are not objects, assume they are indices.
  function computeNodeLinks(graph) {
    graph.nodes.forEach(function(node, i) {
      node.index = i;
      node.sourceLinks = [];
      node.targetLinks = [];
    });
    graph.links.forEach(function(link, i) {
      var source = link.source, target = link.target;
      if (typeof source === "number") source = link.source = graph.nodes[link.source];
      if (typeof target === "number") target = link.target = graph.nodes[link.target];
      link.index = i;
      source.sourceLinks.push(link);
      target.targetLinks.push(link);
    });
  }

  // Compute the value (size) of each node by summing the associated links.
  function computeNodeValues(graph) {
    graph.nodes.forEach(function(node) {
      node.value = Math.max(
        d3Array.sum(node.sourceLinks, value),
        d3Array.sum(node.targetLinks, value)
      );
    });
  }

  // Iteratively assign the depth (x-position) for each node.
  // Nodes are assigned the maximum depth of incoming neighbors plus one;
  // nodes with no incoming links are assigned depth zero, while
  // nodes with no outgoing links are assigned the maximum depth.
  function computeNodeDepths(graph) {
    var remainingNodes = graph.nodes,
        nextNodes,
        depth = 0;

    while (remainingNodes.length) {
      nextNodes = [];
      remainingNodes.forEach(function(node) {
        node.depth = depth;
        node.sourceLinks.forEach(function(link) {
          if (nextNodes.indexOf(link.target) < 0) {
            nextNodes.push(link.target);
          }
        });
      });
      remainingNodes = nextNodes;
      ++depth;
    }

    //
    moveSinksRight(graph, depth);
    scaleNodeDepths(graph, depth);
  }

  // function moveSourcesRight(graph) {
  //   graph.nodes.forEach(function(node) {
  //     if (!node.targetLinks.length) {
  //       node.depth = min(node.sourceLinks, function(d) { return d.target.depth; }) - 1;
  //     }
  //   });
  // }

  function moveSinksRight(graph, depth) {
    graph.nodes.forEach(function(node) {
      if (!node.sourceLinks.length) {
        node.depth = depth - 1;
      }
    });
  }

  function scaleNodeDepths(graph, depth) {
    var kx = (x1 - x0 - dx) / (depth - 1);
    graph.nodes.forEach(function(node) {
      node.x1 = (node.x0 = x0 + node.depth * kx) + dx;
    });
  }

  function computeNodeBreadths(graph) {
    var nodesByDepth = d3Collection.nest()
        .key(function(d) { return d.depth; })
        .sortKeys(d3Array.ascending)
        .entries(graph.nodes)
        .map(function(d) { return d.values; });

    //
    initializeNodeBreadth();
    resolveCollisions();
    for (var alpha = 1, n = iterations; n > 0; --n) {
      relaxRightToLeft(alpha *= 0.99);
      resolveCollisions();
      relaxLeftToRight(alpha);
      resolveCollisions();
    }

    function initializeNodeBreadth() {
      var ky = d3Array.min(nodesByDepth, function(nodes) {
        return (y1 - y0 - (nodes.length - 1) * py) / d3Array.sum(nodes, value);
      });

      nodesByDepth.forEach(function(nodes) {
        nodes.forEach(function(node, i) {
          node.y1 = (node.y0 = i) + node.value * ky;
        });
      });

      graph.links.forEach(function(link) {
        link.width = link.value * ky;
      });
    }

    function relaxLeftToRight(alpha) {
      nodesByDepth.forEach(function(nodes) {
        nodes.forEach(function(node) {
          if (node.targetLinks.length) {
            var dy = (d3Array.sum(node.targetLinks, weightedSource) / d3Array.sum(node.targetLinks, value) - nodeCenter(node)) * alpha;
            node.y0 += dy, node.y1 += dy;
          }
        });
      });
    }

    function relaxRightToLeft(alpha) {
      nodesByDepth.slice().reverse().forEach(function(nodes) {
        nodes.forEach(function(node) {
          if (node.sourceLinks.length) {
            var dy = (d3Array.sum(node.sourceLinks, weightedTarget) / d3Array.sum(node.sourceLinks, value) - nodeCenter(node)) * alpha;
            node.y0 += dy, node.y1 += dy;
          }
        });
      });
    }

    function resolveCollisions() {
      nodesByDepth.forEach(function(nodes) {
        var node,
            dy,
            y = y0,
            n = nodes.length,
            i;

        // Push any overlapping nodes down.
        nodes.sort(ascendingBreadth);
        for (i = 0; i < n; ++i) {
          node = nodes[i];
          dy = y - node.y0;
          if (dy > 0) node.y0 += dy, node.y1 += dy;
          y = node.y1 + py;
        }

        // If the bottommost node goes outside the bounds, push it back up.
        dy = y - py - y1;
        if (dy > 0) {
          y = (node.y0 -= dy), node.y1 -= dy;

          // Push any overlapping nodes back up.
          for (i = n - 2; i >= 0; --i) {
            node = nodes[i];
            dy = node.y1 + py - y;
            if (dy > 0) node.y0 -= dy, node.y1 -= dy;
            y = node.y0;
          }
        }
      });
    }
  }

  function computeLinkBreadths(graph) {
    graph.nodes.forEach(function(node) {
      node.sourceLinks.sort(ascendingTargetBreadth);
      node.targetLinks.sort(ascendingSourceBreadth);
    });
    graph.nodes.forEach(function(node) {
      var y0 = node.y0, y1 = y0;
      node.sourceLinks.forEach(function(link) {
        link.y0 = y0 + link.width / 2, y0 += link.width;
      });
      node.targetLinks.forEach(function(link) {
        link.y1 = y1 + link.width / 2, y1 += link.width;
      });
    });
  }

  return sankey;
};

function horizontalSource(d) {
  return [d.source.x1, d.y0];
}

function horizontalTarget(d) {
  return [d.target.x0, d.y1];
}

var sankeyLinkHorizontal = function() {
  return d3Shape.linkHorizontal()
      .source(horizontalSource)
      .target(horizontalTarget);
};

exports.sankey = sankey;
exports.sankeyLinkHorizontal = sankeyLinkHorizontal;

Object.defineProperty(exports, '__esModule', { value: true });

})));

},{"d3-array":2,"d3-collection":3,"d3-shape":6}],6:[function(require,module,exports){
// https://d3js.org/d3-shape/ Version 1.2.0. Copyright 2017 Mike Bostock.
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('d3-path')) :
	typeof define === 'function' && define.amd ? define(['exports', 'd3-path'], factory) :
	(factory((global.d3 = global.d3 || {}),global.d3));
}(this, (function (exports,d3Path) { 'use strict';

var constant = function(x) {
  return function constant() {
    return x;
  };
};

var abs = Math.abs;
var atan2 = Math.atan2;
var cos = Math.cos;
var max = Math.max;
var min = Math.min;
var sin = Math.sin;
var sqrt = Math.sqrt;

var epsilon = 1e-12;
var pi = Math.PI;
var halfPi = pi / 2;
var tau = 2 * pi;

function acos(x) {
  return x > 1 ? 0 : x < -1 ? pi : Math.acos(x);
}

function asin(x) {
  return x >= 1 ? halfPi : x <= -1 ? -halfPi : Math.asin(x);
}

function arcInnerRadius(d) {
  return d.innerRadius;
}

function arcOuterRadius(d) {
  return d.outerRadius;
}

function arcStartAngle(d) {
  return d.startAngle;
}

function arcEndAngle(d) {
  return d.endAngle;
}

function arcPadAngle(d) {
  return d && d.padAngle; // Note: optional!
}

function intersect(x0, y0, x1, y1, x2, y2, x3, y3) {
  var x10 = x1 - x0, y10 = y1 - y0,
      x32 = x3 - x2, y32 = y3 - y2,
      t = (x32 * (y0 - y2) - y32 * (x0 - x2)) / (y32 * x10 - x32 * y10);
  return [x0 + t * x10, y0 + t * y10];
}

// Compute perpendicular offset line of length rc.
// http://mathworld.wolfram.com/Circle-LineIntersection.html
function cornerTangents(x0, y0, x1, y1, r1, rc, cw) {
  var x01 = x0 - x1,
      y01 = y0 - y1,
      lo = (cw ? rc : -rc) / sqrt(x01 * x01 + y01 * y01),
      ox = lo * y01,
      oy = -lo * x01,
      x11 = x0 + ox,
      y11 = y0 + oy,
      x10 = x1 + ox,
      y10 = y1 + oy,
      x00 = (x11 + x10) / 2,
      y00 = (y11 + y10) / 2,
      dx = x10 - x11,
      dy = y10 - y11,
      d2 = dx * dx + dy * dy,
      r = r1 - rc,
      D = x11 * y10 - x10 * y11,
      d = (dy < 0 ? -1 : 1) * sqrt(max(0, r * r * d2 - D * D)),
      cx0 = (D * dy - dx * d) / d2,
      cy0 = (-D * dx - dy * d) / d2,
      cx1 = (D * dy + dx * d) / d2,
      cy1 = (-D * dx + dy * d) / d2,
      dx0 = cx0 - x00,
      dy0 = cy0 - y00,
      dx1 = cx1 - x00,
      dy1 = cy1 - y00;

  // Pick the closer of the two intersection points.
  // TODO Is there a faster way to determine which intersection to use?
  if (dx0 * dx0 + dy0 * dy0 > dx1 * dx1 + dy1 * dy1) cx0 = cx1, cy0 = cy1;

  return {
    cx: cx0,
    cy: cy0,
    x01: -ox,
    y01: -oy,
    x11: cx0 * (r1 / r - 1),
    y11: cy0 * (r1 / r - 1)
  };
}

var arc = function() {
  var innerRadius = arcInnerRadius,
      outerRadius = arcOuterRadius,
      cornerRadius = constant(0),
      padRadius = null,
      startAngle = arcStartAngle,
      endAngle = arcEndAngle,
      padAngle = arcPadAngle,
      context = null;

  function arc() {
    var buffer,
        r,
        r0 = +innerRadius.apply(this, arguments),
        r1 = +outerRadius.apply(this, arguments),
        a0 = startAngle.apply(this, arguments) - halfPi,
        a1 = endAngle.apply(this, arguments) - halfPi,
        da = abs(a1 - a0),
        cw = a1 > a0;

    if (!context) context = buffer = d3Path.path();

    // Ensure that the outer radius is always larger than the inner radius.
    if (r1 < r0) r = r1, r1 = r0, r0 = r;

    // Is it a point?
    if (!(r1 > epsilon)) context.moveTo(0, 0);

    // Or is it a circle or annulus?
    else if (da > tau - epsilon) {
      context.moveTo(r1 * cos(a0), r1 * sin(a0));
      context.arc(0, 0, r1, a0, a1, !cw);
      if (r0 > epsilon) {
        context.moveTo(r0 * cos(a1), r0 * sin(a1));
        context.arc(0, 0, r0, a1, a0, cw);
      }
    }

    // Or is it a circular or annular sector?
    else {
      var a01 = a0,
          a11 = a1,
          a00 = a0,
          a10 = a1,
          da0 = da,
          da1 = da,
          ap = padAngle.apply(this, arguments) / 2,
          rp = (ap > epsilon) && (padRadius ? +padRadius.apply(this, arguments) : sqrt(r0 * r0 + r1 * r1)),
          rc = min(abs(r1 - r0) / 2, +cornerRadius.apply(this, arguments)),
          rc0 = rc,
          rc1 = rc,
          t0,
          t1;

      // Apply padding? Note that since r1 ≥ r0, da1 ≥ da0.
      if (rp > epsilon) {
        var p0 = asin(rp / r0 * sin(ap)),
            p1 = asin(rp / r1 * sin(ap));
        if ((da0 -= p0 * 2) > epsilon) p0 *= (cw ? 1 : -1), a00 += p0, a10 -= p0;
        else da0 = 0, a00 = a10 = (a0 + a1) / 2;
        if ((da1 -= p1 * 2) > epsilon) p1 *= (cw ? 1 : -1), a01 += p1, a11 -= p1;
        else da1 = 0, a01 = a11 = (a0 + a1) / 2;
      }

      var x01 = r1 * cos(a01),
          y01 = r1 * sin(a01),
          x10 = r0 * cos(a10),
          y10 = r0 * sin(a10);

      // Apply rounded corners?
      if (rc > epsilon) {
        var x11 = r1 * cos(a11),
            y11 = r1 * sin(a11),
            x00 = r0 * cos(a00),
            y00 = r0 * sin(a00);

        // Restrict the corner radius according to the sector angle.
        if (da < pi) {
          var oc = da0 > epsilon ? intersect(x01, y01, x00, y00, x11, y11, x10, y10) : [x10, y10],
              ax = x01 - oc[0],
              ay = y01 - oc[1],
              bx = x11 - oc[0],
              by = y11 - oc[1],
              kc = 1 / sin(acos((ax * bx + ay * by) / (sqrt(ax * ax + ay * ay) * sqrt(bx * bx + by * by))) / 2),
              lc = sqrt(oc[0] * oc[0] + oc[1] * oc[1]);
          rc0 = min(rc, (r0 - lc) / (kc - 1));
          rc1 = min(rc, (r1 - lc) / (kc + 1));
        }
      }

      // Is the sector collapsed to a line?
      if (!(da1 > epsilon)) context.moveTo(x01, y01);

      // Does the sector’s outer ring have rounded corners?
      else if (rc1 > epsilon) {
        t0 = cornerTangents(x00, y00, x01, y01, r1, rc1, cw);
        t1 = cornerTangents(x11, y11, x10, y10, r1, rc1, cw);

        context.moveTo(t0.cx + t0.x01, t0.cy + t0.y01);

        // Have the corners merged?
        if (rc1 < rc) context.arc(t0.cx, t0.cy, rc1, atan2(t0.y01, t0.x01), atan2(t1.y01, t1.x01), !cw);

        // Otherwise, draw the two corners and the ring.
        else {
          context.arc(t0.cx, t0.cy, rc1, atan2(t0.y01, t0.x01), atan2(t0.y11, t0.x11), !cw);
          context.arc(0, 0, r1, atan2(t0.cy + t0.y11, t0.cx + t0.x11), atan2(t1.cy + t1.y11, t1.cx + t1.x11), !cw);
          context.arc(t1.cx, t1.cy, rc1, atan2(t1.y11, t1.x11), atan2(t1.y01, t1.x01), !cw);
        }
      }

      // Or is the outer ring just a circular arc?
      else context.moveTo(x01, y01), context.arc(0, 0, r1, a01, a11, !cw);

      // Is there no inner ring, and it’s a circular sector?
      // Or perhaps it’s an annular sector collapsed due to padding?
      if (!(r0 > epsilon) || !(da0 > epsilon)) context.lineTo(x10, y10);

      // Does the sector’s inner ring (or point) have rounded corners?
      else if (rc0 > epsilon) {
        t0 = cornerTangents(x10, y10, x11, y11, r0, -rc0, cw);
        t1 = cornerTangents(x01, y01, x00, y00, r0, -rc0, cw);

        context.lineTo(t0.cx + t0.x01, t0.cy + t0.y01);

        // Have the corners merged?
        if (rc0 < rc) context.arc(t0.cx, t0.cy, rc0, atan2(t0.y01, t0.x01), atan2(t1.y01, t1.x01), !cw);

        // Otherwise, draw the two corners and the ring.
        else {
          context.arc(t0.cx, t0.cy, rc0, atan2(t0.y01, t0.x01), atan2(t0.y11, t0.x11), !cw);
          context.arc(0, 0, r0, atan2(t0.cy + t0.y11, t0.cx + t0.x11), atan2(t1.cy + t1.y11, t1.cx + t1.x11), cw);
          context.arc(t1.cx, t1.cy, rc0, atan2(t1.y11, t1.x11), atan2(t1.y01, t1.x01), !cw);
        }
      }

      // Or is the inner ring just a circular arc?
      else context.arc(0, 0, r0, a10, a00, cw);
    }

    context.closePath();

    if (buffer) return context = null, buffer + "" || null;
  }

  arc.centroid = function() {
    var r = (+innerRadius.apply(this, arguments) + +outerRadius.apply(this, arguments)) / 2,
        a = (+startAngle.apply(this, arguments) + +endAngle.apply(this, arguments)) / 2 - pi / 2;
    return [cos(a) * r, sin(a) * r];
  };

  arc.innerRadius = function(_) {
    return arguments.length ? (innerRadius = typeof _ === "function" ? _ : constant(+_), arc) : innerRadius;
  };

  arc.outerRadius = function(_) {
    return arguments.length ? (outerRadius = typeof _ === "function" ? _ : constant(+_), arc) : outerRadius;
  };

  arc.cornerRadius = function(_) {
    return arguments.length ? (cornerRadius = typeof _ === "function" ? _ : constant(+_), arc) : cornerRadius;
  };

  arc.padRadius = function(_) {
    return arguments.length ? (padRadius = _ == null ? null : typeof _ === "function" ? _ : constant(+_), arc) : padRadius;
  };

  arc.startAngle = function(_) {
    return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant(+_), arc) : startAngle;
  };

  arc.endAngle = function(_) {
    return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant(+_), arc) : endAngle;
  };

  arc.padAngle = function(_) {
    return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant(+_), arc) : padAngle;
  };

  arc.context = function(_) {
    return arguments.length ? ((context = _ == null ? null : _), arc) : context;
  };

  return arc;
};

function Linear(context) {
  this._context = context;
}

Linear.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._point = 0;
  },
  lineEnd: function() {
    if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
      case 1: this._point = 2; // proceed
      default: this._context.lineTo(x, y); break;
    }
  }
};

var curveLinear = function(context) {
  return new Linear(context);
};

function x(p) {
  return p[0];
}

function y(p) {
  return p[1];
}

var line = function() {
  var x$$1 = x,
      y$$1 = y,
      defined = constant(true),
      context = null,
      curve = curveLinear,
      output = null;

  function line(data) {
    var i,
        n = data.length,
        d,
        defined0 = false,
        buffer;

    if (context == null) output = curve(buffer = d3Path.path());

    for (i = 0; i <= n; ++i) {
      if (!(i < n && defined(d = data[i], i, data)) === defined0) {
        if (defined0 = !defined0) output.lineStart();
        else output.lineEnd();
      }
      if (defined0) output.point(+x$$1(d, i, data), +y$$1(d, i, data));
    }

    if (buffer) return output = null, buffer + "" || null;
  }

  line.x = function(_) {
    return arguments.length ? (x$$1 = typeof _ === "function" ? _ : constant(+_), line) : x$$1;
  };

  line.y = function(_) {
    return arguments.length ? (y$$1 = typeof _ === "function" ? _ : constant(+_), line) : y$$1;
  };

  line.defined = function(_) {
    return arguments.length ? (defined = typeof _ === "function" ? _ : constant(!!_), line) : defined;
  };

  line.curve = function(_) {
    return arguments.length ? (curve = _, context != null && (output = curve(context)), line) : curve;
  };

  line.context = function(_) {
    return arguments.length ? (_ == null ? context = output = null : output = curve(context = _), line) : context;
  };

  return line;
};

var area = function() {
  var x0 = x,
      x1 = null,
      y0 = constant(0),
      y1 = y,
      defined = constant(true),
      context = null,
      curve = curveLinear,
      output = null;

  function area(data) {
    var i,
        j,
        k,
        n = data.length,
        d,
        defined0 = false,
        buffer,
        x0z = new Array(n),
        y0z = new Array(n);

    if (context == null) output = curve(buffer = d3Path.path());

    for (i = 0; i <= n; ++i) {
      if (!(i < n && defined(d = data[i], i, data)) === defined0) {
        if (defined0 = !defined0) {
          j = i;
          output.areaStart();
          output.lineStart();
        } else {
          output.lineEnd();
          output.lineStart();
          for (k = i - 1; k >= j; --k) {
            output.point(x0z[k], y0z[k]);
          }
          output.lineEnd();
          output.areaEnd();
        }
      }
      if (defined0) {
        x0z[i] = +x0(d, i, data), y0z[i] = +y0(d, i, data);
        output.point(x1 ? +x1(d, i, data) : x0z[i], y1 ? +y1(d, i, data) : y0z[i]);
      }
    }

    if (buffer) return output = null, buffer + "" || null;
  }

  function arealine() {
    return line().defined(defined).curve(curve).context(context);
  }

  area.x = function(_) {
    return arguments.length ? (x0 = typeof _ === "function" ? _ : constant(+_), x1 = null, area) : x0;
  };

  area.x0 = function(_) {
    return arguments.length ? (x0 = typeof _ === "function" ? _ : constant(+_), area) : x0;
  };

  area.x1 = function(_) {
    return arguments.length ? (x1 = _ == null ? null : typeof _ === "function" ? _ : constant(+_), area) : x1;
  };

  area.y = function(_) {
    return arguments.length ? (y0 = typeof _ === "function" ? _ : constant(+_), y1 = null, area) : y0;
  };

  area.y0 = function(_) {
    return arguments.length ? (y0 = typeof _ === "function" ? _ : constant(+_), area) : y0;
  };

  area.y1 = function(_) {
    return arguments.length ? (y1 = _ == null ? null : typeof _ === "function" ? _ : constant(+_), area) : y1;
  };

  area.lineX0 =
  area.lineY0 = function() {
    return arealine().x(x0).y(y0);
  };

  area.lineY1 = function() {
    return arealine().x(x0).y(y1);
  };

  area.lineX1 = function() {
    return arealine().x(x1).y(y0);
  };

  area.defined = function(_) {
    return arguments.length ? (defined = typeof _ === "function" ? _ : constant(!!_), area) : defined;
  };

  area.curve = function(_) {
    return arguments.length ? (curve = _, context != null && (output = curve(context)), area) : curve;
  };

  area.context = function(_) {
    return arguments.length ? (_ == null ? context = output = null : output = curve(context = _), area) : context;
  };

  return area;
};

var descending = function(a, b) {
  return b < a ? -1 : b > a ? 1 : b >= a ? 0 : NaN;
};

var identity = function(d) {
  return d;
};

var pie = function() {
  var value = identity,
      sortValues = descending,
      sort = null,
      startAngle = constant(0),
      endAngle = constant(tau),
      padAngle = constant(0);

  function pie(data) {
    var i,
        n = data.length,
        j,
        k,
        sum = 0,
        index = new Array(n),
        arcs = new Array(n),
        a0 = +startAngle.apply(this, arguments),
        da = Math.min(tau, Math.max(-tau, endAngle.apply(this, arguments) - a0)),
        a1,
        p = Math.min(Math.abs(da) / n, padAngle.apply(this, arguments)),
        pa = p * (da < 0 ? -1 : 1),
        v;

    for (i = 0; i < n; ++i) {
      if ((v = arcs[index[i] = i] = +value(data[i], i, data)) > 0) {
        sum += v;
      }
    }

    // Optionally sort the arcs by previously-computed values or by data.
    if (sortValues != null) index.sort(function(i, j) { return sortValues(arcs[i], arcs[j]); });
    else if (sort != null) index.sort(function(i, j) { return sort(data[i], data[j]); });

    // Compute the arcs! They are stored in the original data's order.
    for (i = 0, k = sum ? (da - n * pa) / sum : 0; i < n; ++i, a0 = a1) {
      j = index[i], v = arcs[j], a1 = a0 + (v > 0 ? v * k : 0) + pa, arcs[j] = {
        data: data[j],
        index: i,
        value: v,
        startAngle: a0,
        endAngle: a1,
        padAngle: p
      };
    }

    return arcs;
  }

  pie.value = function(_) {
    return arguments.length ? (value = typeof _ === "function" ? _ : constant(+_), pie) : value;
  };

  pie.sortValues = function(_) {
    return arguments.length ? (sortValues = _, sort = null, pie) : sortValues;
  };

  pie.sort = function(_) {
    return arguments.length ? (sort = _, sortValues = null, pie) : sort;
  };

  pie.startAngle = function(_) {
    return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant(+_), pie) : startAngle;
  };

  pie.endAngle = function(_) {
    return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant(+_), pie) : endAngle;
  };

  pie.padAngle = function(_) {
    return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant(+_), pie) : padAngle;
  };

  return pie;
};

var curveRadialLinear = curveRadial(curveLinear);

function Radial(curve) {
  this._curve = curve;
}

Radial.prototype = {
  areaStart: function() {
    this._curve.areaStart();
  },
  areaEnd: function() {
    this._curve.areaEnd();
  },
  lineStart: function() {
    this._curve.lineStart();
  },
  lineEnd: function() {
    this._curve.lineEnd();
  },
  point: function(a, r) {
    this._curve.point(r * Math.sin(a), r * -Math.cos(a));
  }
};

function curveRadial(curve) {

  function radial(context) {
    return new Radial(curve(context));
  }

  radial._curve = curve;

  return radial;
}

function lineRadial(l) {
  var c = l.curve;

  l.angle = l.x, delete l.x;
  l.radius = l.y, delete l.y;

  l.curve = function(_) {
    return arguments.length ? c(curveRadial(_)) : c()._curve;
  };

  return l;
}

var lineRadial$1 = function() {
  return lineRadial(line().curve(curveRadialLinear));
};

var areaRadial = function() {
  var a = area().curve(curveRadialLinear),
      c = a.curve,
      x0 = a.lineX0,
      x1 = a.lineX1,
      y0 = a.lineY0,
      y1 = a.lineY1;

  a.angle = a.x, delete a.x;
  a.startAngle = a.x0, delete a.x0;
  a.endAngle = a.x1, delete a.x1;
  a.radius = a.y, delete a.y;
  a.innerRadius = a.y0, delete a.y0;
  a.outerRadius = a.y1, delete a.y1;
  a.lineStartAngle = function() { return lineRadial(x0()); }, delete a.lineX0;
  a.lineEndAngle = function() { return lineRadial(x1()); }, delete a.lineX1;
  a.lineInnerRadius = function() { return lineRadial(y0()); }, delete a.lineY0;
  a.lineOuterRadius = function() { return lineRadial(y1()); }, delete a.lineY1;

  a.curve = function(_) {
    return arguments.length ? c(curveRadial(_)) : c()._curve;
  };

  return a;
};

var pointRadial = function(x, y) {
  return [(y = +y) * Math.cos(x -= Math.PI / 2), y * Math.sin(x)];
};

var slice = Array.prototype.slice;

function linkSource(d) {
  return d.source;
}

function linkTarget(d) {
  return d.target;
}

function link(curve) {
  var source = linkSource,
      target = linkTarget,
      x$$1 = x,
      y$$1 = y,
      context = null;

  function link() {
    var buffer, argv = slice.call(arguments), s = source.apply(this, argv), t = target.apply(this, argv);
    if (!context) context = buffer = d3Path.path();
    curve(context, +x$$1.apply(this, (argv[0] = s, argv)), +y$$1.apply(this, argv), +x$$1.apply(this, (argv[0] = t, argv)), +y$$1.apply(this, argv));
    if (buffer) return context = null, buffer + "" || null;
  }

  link.source = function(_) {
    return arguments.length ? (source = _, link) : source;
  };

  link.target = function(_) {
    return arguments.length ? (target = _, link) : target;
  };

  link.x = function(_) {
    return arguments.length ? (x$$1 = typeof _ === "function" ? _ : constant(+_), link) : x$$1;
  };

  link.y = function(_) {
    return arguments.length ? (y$$1 = typeof _ === "function" ? _ : constant(+_), link) : y$$1;
  };

  link.context = function(_) {
    return arguments.length ? ((context = _ == null ? null : _), link) : context;
  };

  return link;
}

function curveHorizontal(context, x0, y0, x1, y1) {
  context.moveTo(x0, y0);
  context.bezierCurveTo(x0 = (x0 + x1) / 2, y0, x0, y1, x1, y1);
}

function curveVertical(context, x0, y0, x1, y1) {
  context.moveTo(x0, y0);
  context.bezierCurveTo(x0, y0 = (y0 + y1) / 2, x1, y0, x1, y1);
}

function curveRadial$1(context, x0, y0, x1, y1) {
  var p0 = pointRadial(x0, y0),
      p1 = pointRadial(x0, y0 = (y0 + y1) / 2),
      p2 = pointRadial(x1, y0),
      p3 = pointRadial(x1, y1);
  context.moveTo(p0[0], p0[1]);
  context.bezierCurveTo(p1[0], p1[1], p2[0], p2[1], p3[0], p3[1]);
}

function linkHorizontal() {
  return link(curveHorizontal);
}

function linkVertical() {
  return link(curveVertical);
}

function linkRadial() {
  var l = link(curveRadial$1);
  l.angle = l.x, delete l.x;
  l.radius = l.y, delete l.y;
  return l;
}

var circle = {
  draw: function(context, size) {
    var r = Math.sqrt(size / pi);
    context.moveTo(r, 0);
    context.arc(0, 0, r, 0, tau);
  }
};

var cross = {
  draw: function(context, size) {
    var r = Math.sqrt(size / 5) / 2;
    context.moveTo(-3 * r, -r);
    context.lineTo(-r, -r);
    context.lineTo(-r, -3 * r);
    context.lineTo(r, -3 * r);
    context.lineTo(r, -r);
    context.lineTo(3 * r, -r);
    context.lineTo(3 * r, r);
    context.lineTo(r, r);
    context.lineTo(r, 3 * r);
    context.lineTo(-r, 3 * r);
    context.lineTo(-r, r);
    context.lineTo(-3 * r, r);
    context.closePath();
  }
};

var tan30 = Math.sqrt(1 / 3);
var tan30_2 = tan30 * 2;

var diamond = {
  draw: function(context, size) {
    var y = Math.sqrt(size / tan30_2),
        x = y * tan30;
    context.moveTo(0, -y);
    context.lineTo(x, 0);
    context.lineTo(0, y);
    context.lineTo(-x, 0);
    context.closePath();
  }
};

var ka = 0.89081309152928522810;
var kr = Math.sin(pi / 10) / Math.sin(7 * pi / 10);
var kx = Math.sin(tau / 10) * kr;
var ky = -Math.cos(tau / 10) * kr;

var star = {
  draw: function(context, size) {
    var r = Math.sqrt(size * ka),
        x = kx * r,
        y = ky * r;
    context.moveTo(0, -r);
    context.lineTo(x, y);
    for (var i = 1; i < 5; ++i) {
      var a = tau * i / 5,
          c = Math.cos(a),
          s = Math.sin(a);
      context.lineTo(s * r, -c * r);
      context.lineTo(c * x - s * y, s * x + c * y);
    }
    context.closePath();
  }
};

var square = {
  draw: function(context, size) {
    var w = Math.sqrt(size),
        x = -w / 2;
    context.rect(x, x, w, w);
  }
};

var sqrt3 = Math.sqrt(3);

var triangle = {
  draw: function(context, size) {
    var y = -Math.sqrt(size / (sqrt3 * 3));
    context.moveTo(0, y * 2);
    context.lineTo(-sqrt3 * y, -y);
    context.lineTo(sqrt3 * y, -y);
    context.closePath();
  }
};

var c = -0.5;
var s = Math.sqrt(3) / 2;
var k = 1 / Math.sqrt(12);
var a = (k / 2 + 1) * 3;

var wye = {
  draw: function(context, size) {
    var r = Math.sqrt(size / a),
        x0 = r / 2,
        y0 = r * k,
        x1 = x0,
        y1 = r * k + r,
        x2 = -x1,
        y2 = y1;
    context.moveTo(x0, y0);
    context.lineTo(x1, y1);
    context.lineTo(x2, y2);
    context.lineTo(c * x0 - s * y0, s * x0 + c * y0);
    context.lineTo(c * x1 - s * y1, s * x1 + c * y1);
    context.lineTo(c * x2 - s * y2, s * x2 + c * y2);
    context.lineTo(c * x0 + s * y0, c * y0 - s * x0);
    context.lineTo(c * x1 + s * y1, c * y1 - s * x1);
    context.lineTo(c * x2 + s * y2, c * y2 - s * x2);
    context.closePath();
  }
};

var symbols = [
  circle,
  cross,
  diamond,
  square,
  star,
  triangle,
  wye
];

var symbol = function() {
  var type = constant(circle),
      size = constant(64),
      context = null;

  function symbol() {
    var buffer;
    if (!context) context = buffer = d3Path.path();
    type.apply(this, arguments).draw(context, +size.apply(this, arguments));
    if (buffer) return context = null, buffer + "" || null;
  }

  symbol.type = function(_) {
    return arguments.length ? (type = typeof _ === "function" ? _ : constant(_), symbol) : type;
  };

  symbol.size = function(_) {
    return arguments.length ? (size = typeof _ === "function" ? _ : constant(+_), symbol) : size;
  };

  symbol.context = function(_) {
    return arguments.length ? (context = _ == null ? null : _, symbol) : context;
  };

  return symbol;
};

var noop = function() {};

function point(that, x, y) {
  that._context.bezierCurveTo(
    (2 * that._x0 + that._x1) / 3,
    (2 * that._y0 + that._y1) / 3,
    (that._x0 + 2 * that._x1) / 3,
    (that._y0 + 2 * that._y1) / 3,
    (that._x0 + 4 * that._x1 + x) / 6,
    (that._y0 + 4 * that._y1 + y) / 6
  );
}

function Basis(context) {
  this._context = context;
}

Basis.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 =
    this._y0 = this._y1 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 3: point(this, this._x1, this._y1); // proceed
      case 2: this._context.lineTo(this._x1, this._y1); break;
    }
    if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
      case 1: this._point = 2; break;
      case 2: this._point = 3; this._context.lineTo((5 * this._x0 + this._x1) / 6, (5 * this._y0 + this._y1) / 6); // proceed
      default: point(this, x, y); break;
    }
    this._x0 = this._x1, this._x1 = x;
    this._y0 = this._y1, this._y1 = y;
  }
};

var basis = function(context) {
  return new Basis(context);
};

function BasisClosed(context) {
  this._context = context;
}

BasisClosed.prototype = {
  areaStart: noop,
  areaEnd: noop,
  lineStart: function() {
    this._x0 = this._x1 = this._x2 = this._x3 = this._x4 =
    this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 1: {
        this._context.moveTo(this._x2, this._y2);
        this._context.closePath();
        break;
      }
      case 2: {
        this._context.moveTo((this._x2 + 2 * this._x3) / 3, (this._y2 + 2 * this._y3) / 3);
        this._context.lineTo((this._x3 + 2 * this._x2) / 3, (this._y3 + 2 * this._y2) / 3);
        this._context.closePath();
        break;
      }
      case 3: {
        this.point(this._x2, this._y2);
        this.point(this._x3, this._y3);
        this.point(this._x4, this._y4);
        break;
      }
    }
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; this._x2 = x, this._y2 = y; break;
      case 1: this._point = 2; this._x3 = x, this._y3 = y; break;
      case 2: this._point = 3; this._x4 = x, this._y4 = y; this._context.moveTo((this._x0 + 4 * this._x1 + x) / 6, (this._y0 + 4 * this._y1 + y) / 6); break;
      default: point(this, x, y); break;
    }
    this._x0 = this._x1, this._x1 = x;
    this._y0 = this._y1, this._y1 = y;
  }
};

var basisClosed = function(context) {
  return new BasisClosed(context);
};

function BasisOpen(context) {
  this._context = context;
}

BasisOpen.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 =
    this._y0 = this._y1 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; break;
      case 1: this._point = 2; break;
      case 2: this._point = 3; var x0 = (this._x0 + 4 * this._x1 + x) / 6, y0 = (this._y0 + 4 * this._y1 + y) / 6; this._line ? this._context.lineTo(x0, y0) : this._context.moveTo(x0, y0); break;
      case 3: this._point = 4; // proceed
      default: point(this, x, y); break;
    }
    this._x0 = this._x1, this._x1 = x;
    this._y0 = this._y1, this._y1 = y;
  }
};

var basisOpen = function(context) {
  return new BasisOpen(context);
};

function Bundle(context, beta) {
  this._basis = new Basis(context);
  this._beta = beta;
}

Bundle.prototype = {
  lineStart: function() {
    this._x = [];
    this._y = [];
    this._basis.lineStart();
  },
  lineEnd: function() {
    var x = this._x,
        y = this._y,
        j = x.length - 1;

    if (j > 0) {
      var x0 = x[0],
          y0 = y[0],
          dx = x[j] - x0,
          dy = y[j] - y0,
          i = -1,
          t;

      while (++i <= j) {
        t = i / j;
        this._basis.point(
          this._beta * x[i] + (1 - this._beta) * (x0 + t * dx),
          this._beta * y[i] + (1 - this._beta) * (y0 + t * dy)
        );
      }
    }

    this._x = this._y = null;
    this._basis.lineEnd();
  },
  point: function(x, y) {
    this._x.push(+x);
    this._y.push(+y);
  }
};

var bundle = ((function custom(beta) {

  function bundle(context) {
    return beta === 1 ? new Basis(context) : new Bundle(context, beta);
  }

  bundle.beta = function(beta) {
    return custom(+beta);
  };

  return bundle;
}))(0.85);

function point$1(that, x, y) {
  that._context.bezierCurveTo(
    that._x1 + that._k * (that._x2 - that._x0),
    that._y1 + that._k * (that._y2 - that._y0),
    that._x2 + that._k * (that._x1 - x),
    that._y2 + that._k * (that._y1 - y),
    that._x2,
    that._y2
  );
}

function Cardinal(context, tension) {
  this._context = context;
  this._k = (1 - tension) / 6;
}

Cardinal.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 = this._x2 =
    this._y0 = this._y1 = this._y2 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 2: this._context.lineTo(this._x2, this._y2); break;
      case 3: point$1(this, this._x1, this._y1); break;
    }
    if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
      case 1: this._point = 2; this._x1 = x, this._y1 = y; break;
      case 2: this._point = 3; // proceed
      default: point$1(this, x, y); break;
    }
    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
  }
};

var cardinal = ((function custom(tension) {

  function cardinal(context) {
    return new Cardinal(context, tension);
  }

  cardinal.tension = function(tension) {
    return custom(+tension);
  };

  return cardinal;
}))(0);

function CardinalClosed(context, tension) {
  this._context = context;
  this._k = (1 - tension) / 6;
}

CardinalClosed.prototype = {
  areaStart: noop,
  areaEnd: noop,
  lineStart: function() {
    this._x0 = this._x1 = this._x2 = this._x3 = this._x4 = this._x5 =
    this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = this._y5 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 1: {
        this._context.moveTo(this._x3, this._y3);
        this._context.closePath();
        break;
      }
      case 2: {
        this._context.lineTo(this._x3, this._y3);
        this._context.closePath();
        break;
      }
      case 3: {
        this.point(this._x3, this._y3);
        this.point(this._x4, this._y4);
        this.point(this._x5, this._y5);
        break;
      }
    }
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; this._x3 = x, this._y3 = y; break;
      case 1: this._point = 2; this._context.moveTo(this._x4 = x, this._y4 = y); break;
      case 2: this._point = 3; this._x5 = x, this._y5 = y; break;
      default: point$1(this, x, y); break;
    }
    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
  }
};

var cardinalClosed = ((function custom(tension) {

  function cardinal(context) {
    return new CardinalClosed(context, tension);
  }

  cardinal.tension = function(tension) {
    return custom(+tension);
  };

  return cardinal;
}))(0);

function CardinalOpen(context, tension) {
  this._context = context;
  this._k = (1 - tension) / 6;
}

CardinalOpen.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 = this._x2 =
    this._y0 = this._y1 = this._y2 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;
    switch (this._point) {
      case 0: this._point = 1; break;
      case 1: this._point = 2; break;
      case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
      case 3: this._point = 4; // proceed
      default: point$1(this, x, y); break;
    }
    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
  }
};

var cardinalOpen = ((function custom(tension) {

  function cardinal(context) {
    return new CardinalOpen(context, tension);
  }

  cardinal.tension = function(tension) {
    return custom(+tension);
  };

  return cardinal;
}))(0);

function point$2(that, x, y) {
  var x1 = that._x1,
      y1 = that._y1,
      x2 = that._x2,
      y2 = that._y2;

  if (that._l01_a > epsilon) {
    var a = 2 * that._l01_2a + 3 * that._l01_a * that._l12_a + that._l12_2a,
        n = 3 * that._l01_a * (that._l01_a + that._l12_a);
    x1 = (x1 * a - that._x0 * that._l12_2a + that._x2 * that._l01_2a) / n;
    y1 = (y1 * a - that._y0 * that._l12_2a + that._y2 * that._l01_2a) / n;
  }

  if (that._l23_a > epsilon) {
    var b = 2 * that._l23_2a + 3 * that._l23_a * that._l12_a + that._l12_2a,
        m = 3 * that._l23_a * (that._l23_a + that._l12_a);
    x2 = (x2 * b + that._x1 * that._l23_2a - x * that._l12_2a) / m;
    y2 = (y2 * b + that._y1 * that._l23_2a - y * that._l12_2a) / m;
  }

  that._context.bezierCurveTo(x1, y1, x2, y2, that._x2, that._y2);
}

function CatmullRom(context, alpha) {
  this._context = context;
  this._alpha = alpha;
}

CatmullRom.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 = this._x2 =
    this._y0 = this._y1 = this._y2 = NaN;
    this._l01_a = this._l12_a = this._l23_a =
    this._l01_2a = this._l12_2a = this._l23_2a =
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 2: this._context.lineTo(this._x2, this._y2); break;
      case 3: this.point(this._x2, this._y2); break;
    }
    if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;

    if (this._point) {
      var x23 = this._x2 - x,
          y23 = this._y2 - y;
      this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
    }

    switch (this._point) {
      case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
      case 1: this._point = 2; break;
      case 2: this._point = 3; // proceed
      default: point$2(this, x, y); break;
    }

    this._l01_a = this._l12_a, this._l12_a = this._l23_a;
    this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
  }
};

var catmullRom = ((function custom(alpha) {

  function catmullRom(context) {
    return alpha ? new CatmullRom(context, alpha) : new Cardinal(context, 0);
  }

  catmullRom.alpha = function(alpha) {
    return custom(+alpha);
  };

  return catmullRom;
}))(0.5);

function CatmullRomClosed(context, alpha) {
  this._context = context;
  this._alpha = alpha;
}

CatmullRomClosed.prototype = {
  areaStart: noop,
  areaEnd: noop,
  lineStart: function() {
    this._x0 = this._x1 = this._x2 = this._x3 = this._x4 = this._x5 =
    this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = this._y5 = NaN;
    this._l01_a = this._l12_a = this._l23_a =
    this._l01_2a = this._l12_2a = this._l23_2a =
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 1: {
        this._context.moveTo(this._x3, this._y3);
        this._context.closePath();
        break;
      }
      case 2: {
        this._context.lineTo(this._x3, this._y3);
        this._context.closePath();
        break;
      }
      case 3: {
        this.point(this._x3, this._y3);
        this.point(this._x4, this._y4);
        this.point(this._x5, this._y5);
        break;
      }
    }
  },
  point: function(x, y) {
    x = +x, y = +y;

    if (this._point) {
      var x23 = this._x2 - x,
          y23 = this._y2 - y;
      this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
    }

    switch (this._point) {
      case 0: this._point = 1; this._x3 = x, this._y3 = y; break;
      case 1: this._point = 2; this._context.moveTo(this._x4 = x, this._y4 = y); break;
      case 2: this._point = 3; this._x5 = x, this._y5 = y; break;
      default: point$2(this, x, y); break;
    }

    this._l01_a = this._l12_a, this._l12_a = this._l23_a;
    this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
  }
};

var catmullRomClosed = ((function custom(alpha) {

  function catmullRom(context) {
    return alpha ? new CatmullRomClosed(context, alpha) : new CardinalClosed(context, 0);
  }

  catmullRom.alpha = function(alpha) {
    return custom(+alpha);
  };

  return catmullRom;
}))(0.5);

function CatmullRomOpen(context, alpha) {
  this._context = context;
  this._alpha = alpha;
}

CatmullRomOpen.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 = this._x2 =
    this._y0 = this._y1 = this._y2 = NaN;
    this._l01_a = this._l12_a = this._l23_a =
    this._l01_2a = this._l12_2a = this._l23_2a =
    this._point = 0;
  },
  lineEnd: function() {
    if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    x = +x, y = +y;

    if (this._point) {
      var x23 = this._x2 - x,
          y23 = this._y2 - y;
      this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
    }

    switch (this._point) {
      case 0: this._point = 1; break;
      case 1: this._point = 2; break;
      case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
      case 3: this._point = 4; // proceed
      default: point$2(this, x, y); break;
    }

    this._l01_a = this._l12_a, this._l12_a = this._l23_a;
    this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
  }
};

var catmullRomOpen = ((function custom(alpha) {

  function catmullRom(context) {
    return alpha ? new CatmullRomOpen(context, alpha) : new CardinalOpen(context, 0);
  }

  catmullRom.alpha = function(alpha) {
    return custom(+alpha);
  };

  return catmullRom;
}))(0.5);

function LinearClosed(context) {
  this._context = context;
}

LinearClosed.prototype = {
  areaStart: noop,
  areaEnd: noop,
  lineStart: function() {
    this._point = 0;
  },
  lineEnd: function() {
    if (this._point) this._context.closePath();
  },
  point: function(x, y) {
    x = +x, y = +y;
    if (this._point) this._context.lineTo(x, y);
    else this._point = 1, this._context.moveTo(x, y);
  }
};

var linearClosed = function(context) {
  return new LinearClosed(context);
};

function sign(x) {
  return x < 0 ? -1 : 1;
}

// Calculate the slopes of the tangents (Hermite-type interpolation) based on
// the following paper: Steffen, M. 1990. A Simple Method for Monotonic
// Interpolation in One Dimension. Astronomy and Astrophysics, Vol. 239, NO.
// NOV(II), P. 443, 1990.
function slope3(that, x2, y2) {
  var h0 = that._x1 - that._x0,
      h1 = x2 - that._x1,
      s0 = (that._y1 - that._y0) / (h0 || h1 < 0 && -0),
      s1 = (y2 - that._y1) / (h1 || h0 < 0 && -0),
      p = (s0 * h1 + s1 * h0) / (h0 + h1);
  return (sign(s0) + sign(s1)) * Math.min(Math.abs(s0), Math.abs(s1), 0.5 * Math.abs(p)) || 0;
}

// Calculate a one-sided slope.
function slope2(that, t) {
  var h = that._x1 - that._x0;
  return h ? (3 * (that._y1 - that._y0) / h - t) / 2 : t;
}

// According to https://en.wikipedia.org/wiki/Cubic_Hermite_spline#Representations
// "you can express cubic Hermite interpolation in terms of cubic Bézier curves
// with respect to the four values p0, p0 + m0 / 3, p1 - m1 / 3, p1".
function point$3(that, t0, t1) {
  var x0 = that._x0,
      y0 = that._y0,
      x1 = that._x1,
      y1 = that._y1,
      dx = (x1 - x0) / 3;
  that._context.bezierCurveTo(x0 + dx, y0 + dx * t0, x1 - dx, y1 - dx * t1, x1, y1);
}

function MonotoneX(context) {
  this._context = context;
}

MonotoneX.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x0 = this._x1 =
    this._y0 = this._y1 =
    this._t0 = NaN;
    this._point = 0;
  },
  lineEnd: function() {
    switch (this._point) {
      case 2: this._context.lineTo(this._x1, this._y1); break;
      case 3: point$3(this, this._t0, slope2(this, this._t0)); break;
    }
    if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
    this._line = 1 - this._line;
  },
  point: function(x, y) {
    var t1 = NaN;

    x = +x, y = +y;
    if (x === this._x1 && y === this._y1) return; // Ignore coincident points.
    switch (this._point) {
      case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
      case 1: this._point = 2; break;
      case 2: this._point = 3; point$3(this, slope2(this, t1 = slope3(this, x, y)), t1); break;
      default: point$3(this, this._t0, t1 = slope3(this, x, y)); break;
    }

    this._x0 = this._x1, this._x1 = x;
    this._y0 = this._y1, this._y1 = y;
    this._t0 = t1;
  }
};

function MonotoneY(context) {
  this._context = new ReflectContext(context);
}

(MonotoneY.prototype = Object.create(MonotoneX.prototype)).point = function(x, y) {
  MonotoneX.prototype.point.call(this, y, x);
};

function ReflectContext(context) {
  this._context = context;
}

ReflectContext.prototype = {
  moveTo: function(x, y) { this._context.moveTo(y, x); },
  closePath: function() { this._context.closePath(); },
  lineTo: function(x, y) { this._context.lineTo(y, x); },
  bezierCurveTo: function(x1, y1, x2, y2, x, y) { this._context.bezierCurveTo(y1, x1, y2, x2, y, x); }
};

function monotoneX(context) {
  return new MonotoneX(context);
}

function monotoneY(context) {
  return new MonotoneY(context);
}

function Natural(context) {
  this._context = context;
}

Natural.prototype = {
  areaStart: function() {
    this._line = 0;
  },
  areaEnd: function() {
    this._line = NaN;
  },
  lineStart: function() {
    this._x = [];
    this._y = [];
  },
  lineEnd: function() {
    var x = this._x,
        y = this._y,
        n = x.length;

    if (n) {
      this._line ? this._context.lineTo(x[0], y[0]) : this._context.moveTo(x[0], y[0]);
      if (n === 2) {
        this._context.lineTo(x[1], y[1]);
      } else {
        var px = controlPoints(x),