StackGenVis/frontend/node_modules/d3-zoomable/dist/d3-zoomable.js

// Version 1.1.1 d3-zoomable - https://github.com/vasturiano/d3-zoomable
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = global || self, global.zoomable = factory());
}(this, function () { 'use strict';

  function _typeof(obj) {
    if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") {
      _typeof = function (obj) {
        return typeof obj;
      };
    } else {
      _typeof = function (obj) {
        return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
      };
    }

    return _typeof(obj);
  }

  function _defineProperty(obj, key, value) {
    if (key in obj) {
      Object.defineProperty(obj, key, {
        value: value,
        enumerable: true,
        configurable: true,
        writable: true
      });
    } else {
      obj[key] = value;
    }

    return obj;
  }

  function _objectSpread(target) {
    for (var i = 1; i < arguments.length; i++) {
      var source = arguments[i] != null ? arguments[i] : {};
      var ownKeys = Object.keys(source);

      if (typeof Object.getOwnPropertySymbols === 'function') {
        ownKeys = ownKeys.concat(Object.getOwnPropertySymbols(source).filter(function (sym) {
          return Object.getOwnPropertyDescriptor(source, sym).enumerable;
        }));
      }

      ownKeys.forEach(function (key) {
        _defineProperty(target, key, source[key]);
      });
    }

    return target;
  }

  var xhtml = "http://www.w3.org/1999/xhtml";

  var namespaces = {
    svg: "http://www.w3.org/2000/svg",
    xhtml: xhtml,
    xlink: "http://www.w3.org/1999/xlink",
    xml: "http://www.w3.org/XML/1998/namespace",
    xmlns: "http://www.w3.org/2000/xmlns/"
  };

  function namespace(name) {
    var prefix = name += "", i = prefix.indexOf(":");
    if (i >= 0 && (prefix = name.slice(0, i)) !== "xmlns") name = name.slice(i + 1);
    return namespaces.hasOwnProperty(prefix) ? {space: namespaces[prefix], local: name} : name;
  }

  function creatorInherit(name) {
    return function() {
      var document = this.ownerDocument,
          uri = this.namespaceURI;
      return uri === xhtml && document.documentElement.namespaceURI === xhtml
          ? document.createElement(name)
          : document.createElementNS(uri, name);
    };
  }

  function creatorFixed(fullname) {
    return function() {
      return this.ownerDocument.createElementNS(fullname.space, fullname.local);
    };
  }

  function creator(name) {
    var fullname = namespace(name);
    return (fullname.local
        ? creatorFixed
        : creatorInherit)(fullname);
  }

  function none() {}

  function selector(selector) {
    return selector == null ? none : function() {
      return this.querySelector(selector);
    };
  }

  function selection_select(select) {
    if (typeof select !== "function") select = selector(select);

    for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, subgroup = subgroups[j] = new Array(n), node, subnode, i = 0; i < n; ++i) {
        if ((node = group[i]) && (subnode = select.call(node, node.__data__, i, group))) {
          if ("__data__" in node) subnode.__data__ = node.__data__;
          subgroup[i] = subnode;
        }
      }
    }

    return new Selection(subgroups, this._parents);
  }

  function empty() {
    return [];
  }

  function selectorAll(selector) {
    return selector == null ? empty : function() {
      return this.querySelectorAll(selector);
    };
  }

  function selection_selectAll(select) {
    if (typeof select !== "function") select = selectorAll(select);

    for (var groups = this._groups, m = groups.length, subgroups = [], parents = [], j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
        if (node = group[i]) {
          subgroups.push(select.call(node, node.__data__, i, group));
          parents.push(node);
        }
      }
    }

    return new Selection(subgroups, parents);
  }

  function matcher(selector) {
    return function() {
      return this.matches(selector);
    };
  }

  function selection_filter(match) {
    if (typeof match !== "function") match = matcher(match);

    for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, subgroup = subgroups[j] = [], node, i = 0; i < n; ++i) {
        if ((node = group[i]) && match.call(node, node.__data__, i, group)) {
          subgroup.push(node);
        }
      }
    }

    return new Selection(subgroups, this._parents);
  }

  function sparse(update) {
    return new Array(update.length);
  }

  function selection_enter() {
    return new Selection(this._enter || this._groups.map(sparse), this._parents);
  }

  function EnterNode(parent, datum) {
    this.ownerDocument = parent.ownerDocument;
    this.namespaceURI = parent.namespaceURI;
    this._next = null;
    this._parent = parent;
    this.__data__ = datum;
  }

  EnterNode.prototype = {
    constructor: EnterNode,
    appendChild: function(child) { return this._parent.insertBefore(child, this._next); },
    insertBefore: function(child, next) { return this._parent.insertBefore(child, next); },
    querySelector: function(selector) { return this._parent.querySelector(selector); },
    querySelectorAll: function(selector) { return this._parent.querySelectorAll(selector); }
  };

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

  var keyPrefix = "$"; // Protect against keys like “__proto__”.

  function bindIndex(parent, group, enter, update, exit, data) {
    var i = 0,
        node,
        groupLength = group.length,
        dataLength = data.length;

    // Put any non-null nodes that fit into update.
    // Put any null nodes into enter.
    // Put any remaining data into enter.
    for (; i < dataLength; ++i) {
      if (node = group[i]) {
        node.__data__ = data[i];
        update[i] = node;
      } else {
        enter[i] = new EnterNode(parent, data[i]);
      }
    }

    // Put any non-null nodes that don’t fit into exit.
    for (; i < groupLength; ++i) {
      if (node = group[i]) {
        exit[i] = node;
      }
    }
  }

  function bindKey(parent, group, enter, update, exit, data, key) {
    var i,
        node,
        nodeByKeyValue = {},
        groupLength = group.length,
        dataLength = data.length,
        keyValues = new Array(groupLength),
        keyValue;

    // Compute the key for each node.
    // If multiple nodes have the same key, the duplicates are added to exit.
    for (i = 0; i < groupLength; ++i) {
      if (node = group[i]) {
        keyValues[i] = keyValue = keyPrefix + key.call(node, node.__data__, i, group);
        if (keyValue in nodeByKeyValue) {
          exit[i] = node;
        } else {
          nodeByKeyValue[keyValue] = node;
        }
      }
    }

    // Compute the key for each datum.
    // If there a node associated with this key, join and add it to update.
    // If there is not (or the key is a duplicate), add it to enter.
    for (i = 0; i < dataLength; ++i) {
      keyValue = keyPrefix + key.call(parent, data[i], i, data);
      if (node = nodeByKeyValue[keyValue]) {
        update[i] = node;
        node.__data__ = data[i];
        nodeByKeyValue[keyValue] = null;
      } else {
        enter[i] = new EnterNode(parent, data[i]);
      }
    }

    // Add any remaining nodes that were not bound to data to exit.
    for (i = 0; i < groupLength; ++i) {
      if ((node = group[i]) && (nodeByKeyValue[keyValues[i]] === node)) {
        exit[i] = node;
      }
    }
  }

  function selection_data(value, key) {
    if (!value) {
      data = new Array(this.size()), j = -1;
      this.each(function(d) { data[++j] = d; });
      return data;
    }

    var bind = key ? bindKey : bindIndex,
        parents = this._parents,
        groups = this._groups;

    if (typeof value !== "function") value = constant(value);

    for (var m = groups.length, update = new Array(m), enter = new Array(m), exit = new Array(m), j = 0; j < m; ++j) {
      var parent = parents[j],
          group = groups[j],
          groupLength = group.length,
          data = value.call(parent, parent && parent.__data__, j, parents),
          dataLength = data.length,
          enterGroup = enter[j] = new Array(dataLength),
          updateGroup = update[j] = new Array(dataLength),
          exitGroup = exit[j] = new Array(groupLength);

      bind(parent, group, enterGroup, updateGroup, exitGroup, data, key);

      // Now connect the enter nodes to their following update node, such that
      // appendChild can insert the materialized enter node before this node,
      // rather than at the end of the parent node.
      for (var i0 = 0, i1 = 0, previous, next; i0 < dataLength; ++i0) {
        if (previous = enterGroup[i0]) {
          if (i0 >= i1) i1 = i0 + 1;
          while (!(next = updateGroup[i1]) && ++i1 < dataLength);
          previous._next = next || null;
        }
      }
    }

    update = new Selection(update, parents);
    update._enter = enter;
    update._exit = exit;
    return update;
  }

  function selection_exit() {
    return new Selection(this._exit || this._groups.map(sparse), this._parents);
  }

  function selection_join(onenter, onupdate, onexit) {
    var enter = this.enter(), update = this, exit = this.exit();
    enter = typeof onenter === "function" ? onenter(enter) : enter.append(onenter + "");
    if (onupdate != null) update = onupdate(update);
    if (onexit == null) exit.remove(); else onexit(exit);
    return enter && update ? enter.merge(update).order() : update;
  }

  function selection_merge(selection) {

    for (var groups0 = this._groups, groups1 = selection._groups, m0 = groups0.length, m1 = groups1.length, m = Math.min(m0, m1), merges = new Array(m0), j = 0; j < m; ++j) {
      for (var group0 = groups0[j], group1 = groups1[j], n = group0.length, merge = merges[j] = new Array(n), node, i = 0; i < n; ++i) {
        if (node = group0[i] || group1[i]) {
          merge[i] = node;
        }
      }
    }

    for (; j < m0; ++j) {
      merges[j] = groups0[j];
    }

    return new Selection(merges, this._parents);
  }

  function selection_order() {

    for (var groups = this._groups, j = -1, m = groups.length; ++j < m;) {
      for (var group = groups[j], i = group.length - 1, next = group[i], node; --i >= 0;) {
        if (node = group[i]) {
          if (next && node.compareDocumentPosition(next) ^ 4) next.parentNode.insertBefore(node, next);
          next = node;
        }
      }
    }

    return this;
  }

  function selection_sort(compare) {
    if (!compare) compare = ascending;

    function compareNode(a, b) {
      return a && b ? compare(a.__data__, b.__data__) : !a - !b;
    }

    for (var groups = this._groups, m = groups.length, sortgroups = new Array(m), j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, sortgroup = sortgroups[j] = new Array(n), node, i = 0; i < n; ++i) {
        if (node = group[i]) {
          sortgroup[i] = node;
        }
      }
      sortgroup.sort(compareNode);
    }

    return new Selection(sortgroups, this._parents).order();
  }

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

  function selection_call() {
    var callback = arguments[0];
    arguments[0] = this;
    callback.apply(null, arguments);
    return this;
  }

  function selection_nodes() {
    var nodes = new Array(this.size()), i = -1;
    this.each(function() { nodes[++i] = this; });
    return nodes;
  }

  function selection_node() {

    for (var groups = this._groups, j = 0, m = groups.length; j < m; ++j) {
      for (var group = groups[j], i = 0, n = group.length; i < n; ++i) {
        var node = group[i];
        if (node) return node;
      }
    }

    return null;
  }

  function selection_size() {
    var size = 0;
    this.each(function() { ++size; });
    return size;
  }

  function selection_empty() {
    return !this.node();
  }

  function selection_each(callback) {

    for (var groups = this._groups, j = 0, m = groups.length; j < m; ++j) {
      for (var group = groups[j], i = 0, n = group.length, node; i < n; ++i) {
        if (node = group[i]) callback.call(node, node.__data__, i, group);
      }
    }

    return this;
  }

  function attrRemove(name) {
    return function() {
      this.removeAttribute(name);
    };
  }

  function attrRemoveNS(fullname) {
    return function() {
      this.removeAttributeNS(fullname.space, fullname.local);
    };
  }

  function attrConstant(name, value) {
    return function() {
      this.setAttribute(name, value);
    };
  }

  function attrConstantNS(fullname, value) {
    return function() {
      this.setAttributeNS(fullname.space, fullname.local, value);
    };
  }

  function attrFunction(name, value) {
    return function() {
      var v = value.apply(this, arguments);
      if (v == null) this.removeAttribute(name);
      else this.setAttribute(name, v);
    };
  }

  function attrFunctionNS(fullname, value) {
    return function() {
      var v = value.apply(this, arguments);
      if (v == null) this.removeAttributeNS(fullname.space, fullname.local);
      else this.setAttributeNS(fullname.space, fullname.local, v);
    };
  }

  function selection_attr(name, value) {
    var fullname = namespace(name);

    if (arguments.length < 2) {
      var node = this.node();
      return fullname.local
          ? node.getAttributeNS(fullname.space, fullname.local)
          : node.getAttribute(fullname);
    }

    return this.each((value == null
        ? (fullname.local ? attrRemoveNS : attrRemove) : (typeof value === "function"
        ? (fullname.local ? attrFunctionNS : attrFunction)
        : (fullname.local ? attrConstantNS : attrConstant)))(fullname, value));
  }

  function defaultView(node) {
    return (node.ownerDocument && node.ownerDocument.defaultView) // node is a Node
        || (node.document && node) // node is a Window
        || node.defaultView; // node is a Document
  }

  function styleRemove(name) {
    return function() {
      this.style.removeProperty(name);
    };
  }

  function styleConstant(name, value, priority) {
    return function() {
      this.style.setProperty(name, value, priority);
    };
  }

  function styleFunction(name, value, priority) {
    return function() {
      var v = value.apply(this, arguments);
      if (v == null) this.style.removeProperty(name);
      else this.style.setProperty(name, v, priority);
    };
  }

  function selection_style(name, value, priority) {
    return arguments.length > 1
        ? this.each((value == null
              ? styleRemove : typeof value === "function"
              ? styleFunction
              : styleConstant)(name, value, priority == null ? "" : priority))
        : styleValue(this.node(), name);
  }

  function styleValue(node, name) {
    return node.style.getPropertyValue(name)
        || defaultView(node).getComputedStyle(node, null).getPropertyValue(name);
  }

  function propertyRemove(name) {
    return function() {
      delete this[name];
    };
  }

  function propertyConstant(name, value) {
    return function() {
      this[name] = value;
    };
  }

  function propertyFunction(name, value) {
    return function() {
      var v = value.apply(this, arguments);
      if (v == null) delete this[name];
      else this[name] = v;
    };
  }

  function selection_property(name, value) {
    return arguments.length > 1
        ? this.each((value == null
            ? propertyRemove : typeof value === "function"
            ? propertyFunction
            : propertyConstant)(name, value))
        : this.node()[name];
  }

  function classArray(string) {
    return string.trim().split(/^|\s+/);
  }

  function classList(node) {
    return node.classList || new ClassList(node);
  }

  function ClassList(node) {
    this._node = node;
    this._names = classArray(node.getAttribute("class") || "");
  }

  ClassList.prototype = {
    add: function(name) {
      var i = this._names.indexOf(name);
      if (i < 0) {
        this._names.push(name);
        this._node.setAttribute("class", this._names.join(" "));
      }
    },
    remove: function(name) {
      var i = this._names.indexOf(name);
      if (i >= 0) {
        this._names.splice(i, 1);
        this._node.setAttribute("class", this._names.join(" "));
      }
    },
    contains: function(name) {
      return this._names.indexOf(name) >= 0;
    }
  };

  function classedAdd(node, names) {
    var list = classList(node), i = -1, n = names.length;
    while (++i < n) list.add(names[i]);
  }

  function classedRemove(node, names) {
    var list = classList(node), i = -1, n = names.length;
    while (++i < n) list.remove(names[i]);
  }

  function classedTrue(names) {
    return function() {
      classedAdd(this, names);
    };
  }

  function classedFalse(names) {
    return function() {
      classedRemove(this, names);
    };
  }

  function classedFunction(names, value) {
    return function() {
      (value.apply(this, arguments) ? classedAdd : classedRemove)(this, names);
    };
  }

  function selection_classed(name, value) {
    var names = classArray(name + "");

    if (arguments.length < 2) {
      var list = classList(this.node()), i = -1, n = names.length;
      while (++i < n) if (!list.contains(names[i])) return false;
      return true;
    }

    return this.each((typeof value === "function"
        ? classedFunction : value
        ? classedTrue
        : classedFalse)(names, value));
  }

  function textRemove() {
    this.textContent = "";
  }

  function textConstant(value) {
    return function() {
      this.textContent = value;
    };
  }

  function textFunction(value) {
    return function() {
      var v = value.apply(this, arguments);
      this.textContent = v == null ? "" : v;
    };
  }

  function selection_text(value) {
    return arguments.length
        ? this.each(value == null
            ? textRemove : (typeof value === "function"
            ? textFunction
            : textConstant)(value))
        : this.node().textContent;
  }

  function htmlRemove() {
    this.innerHTML = "";
  }

  function htmlConstant(value) {
    return function() {
      this.innerHTML = value;
    };
  }

  function htmlFunction(value) {
    return function() {
      var v = value.apply(this, arguments);
      this.innerHTML = v == null ? "" : v;
    };
  }

  function selection_html(value) {
    return arguments.length
        ? this.each(value == null
            ? htmlRemove : (typeof value === "function"
            ? htmlFunction
            : htmlConstant)(value))
        : this.node().innerHTML;
  }

  function raise() {
    if (this.nextSibling) this.parentNode.appendChild(this);
  }

  function selection_raise() {
    return this.each(raise);
  }

  function lower() {
    if (this.previousSibling) this.parentNode.insertBefore(this, this.parentNode.firstChild);
  }

  function selection_lower() {
    return this.each(lower);
  }

  function selection_append(name) {
    var create = typeof name === "function" ? name : creator(name);
    return this.select(function() {
      return this.appendChild(create.apply(this, arguments));
    });
  }

  function constantNull() {
    return null;
  }

  function selection_insert(name, before) {
    var create = typeof name === "function" ? name : creator(name),
        select = before == null ? constantNull : typeof before === "function" ? before : selector(before);
    return this.select(function() {
      return this.insertBefore(create.apply(this, arguments), select.apply(this, arguments) || null);
    });
  }

  function remove() {
    var parent = this.parentNode;
    if (parent) parent.removeChild(this);
  }

  function selection_remove() {
    return this.each(remove);
  }

  function selection_cloneShallow() {
    return this.parentNode.insertBefore(this.cloneNode(false), this.nextSibling);
  }

  function selection_cloneDeep() {
    return this.parentNode.insertBefore(this.cloneNode(true), this.nextSibling);
  }

  function selection_clone(deep) {
    return this.select(deep ? selection_cloneDeep : selection_cloneShallow);
  }

  function selection_datum(value) {
    return arguments.length
        ? this.property("__data__", value)
        : this.node().__data__;
  }

  var filterEvents = {};

  var event = null;

  if (typeof document !== "undefined") {
    var element = document.documentElement;
    if (!("onmouseenter" in element)) {
      filterEvents = {mouseenter: "mouseover", mouseleave: "mouseout"};
    }
  }

  function filterContextListener(listener, index, group) {
    listener = contextListener(listener, index, group);
    return function(event) {
      var related = event.relatedTarget;
      if (!related || (related !== this && !(related.compareDocumentPosition(this) & 8))) {
        listener.call(this, event);
      }
    };
  }

  function contextListener(listener, index, group) {
    return function(event1) {
      var event0 = event; // Events can be reentrant (e.g., focus).
      event = event1;
      try {
        listener.call(this, this.__data__, index, group);
      } finally {
        event = event0;
      }
    };
  }

  function parseTypenames(typenames) {
    return typenames.trim().split(/^|\s+/).map(function(t) {
      var name = "", i = t.indexOf(".");
      if (i >= 0) name = t.slice(i + 1), t = t.slice(0, i);
      return {type: t, name: name};
    });
  }

  function onRemove(typename) {
    return function() {
      var on = this.__on;
      if (!on) return;
      for (var j = 0, i = -1, m = on.length, o; j < m; ++j) {
        if (o = on[j], (!typename.type || o.type === typename.type) && o.name === typename.name) {
          this.removeEventListener(o.type, o.listener, o.capture);
        } else {
          on[++i] = o;
        }
      }
      if (++i) on.length = i;
      else delete this.__on;
    };
  }

  function onAdd(typename, value, capture) {
    var wrap = filterEvents.hasOwnProperty(typename.type) ? filterContextListener : contextListener;
    return function(d, i, group) {
      var on = this.__on, o, listener = wrap(value, i, group);
      if (on) for (var j = 0, m = on.length; j < m; ++j) {
        if ((o = on[j]).type === typename.type && o.name === typename.name) {
          this.removeEventListener(o.type, o.listener, o.capture);
          this.addEventListener(o.type, o.listener = listener, o.capture = capture);
          o.value = value;
          return;
        }
      }
      this.addEventListener(typename.type, listener, capture);
      o = {type: typename.type, name: typename.name, value: value, listener: listener, capture: capture};
      if (!on) this.__on = [o];
      else on.push(o);
    };
  }

  function selection_on(typename, value, capture) {
    var typenames = parseTypenames(typename + ""), i, n = typenames.length, t;

    if (arguments.length < 2) {
      var on = this.node().__on;
      if (on) for (var j = 0, m = on.length, o; j < m; ++j) {
        for (i = 0, o = on[j]; i < n; ++i) {
          if ((t = typenames[i]).type === o.type && t.name === o.name) {
            return o.value;
          }
        }
      }
      return;
    }

    on = value ? onAdd : onRemove;
    if (capture == null) capture = false;
    for (i = 0; i < n; ++i) this.each(on(typenames[i], value, capture));
    return this;
  }

  function customEvent(event1, listener, that, args) {
    var event0 = event;
    event1.sourceEvent = event;
    event = event1;
    try {
      return listener.apply(that, args);
    } finally {
      event = event0;
    }
  }

  function dispatchEvent(node, type, params) {
    var window = defaultView(node),
        event = window.CustomEvent;

    if (typeof event === "function") {
      event = new event(type, params);
    } else {
      event = window.document.createEvent("Event");
      if (params) event.initEvent(type, params.bubbles, params.cancelable), event.detail = params.detail;
      else event.initEvent(type, false, false);
    }

    node.dispatchEvent(event);
  }

  function dispatchConstant(type, params) {
    return function() {
      return dispatchEvent(this, type, params);
    };
  }

  function dispatchFunction(type, params) {
    return function() {
      return dispatchEvent(this, type, params.apply(this, arguments));
    };
  }

  function selection_dispatch(type, params) {
    return this.each((typeof params === "function"
        ? dispatchFunction
        : dispatchConstant)(type, params));
  }

  var root = [null];

  function Selection(groups, parents) {
    this._groups = groups;
    this._parents = parents;
  }

  function selection() {
    return new Selection([[document.documentElement]], root);
  }

  Selection.prototype = selection.prototype = {
    constructor: Selection,
    select: selection_select,
    selectAll: selection_selectAll,
    filter: selection_filter,
    data: selection_data,
    enter: selection_enter,
    exit: selection_exit,
    join: selection_join,
    merge: selection_merge,
    order: selection_order,
    sort: selection_sort,
    call: selection_call,
    nodes: selection_nodes,
    node: selection_node,
    size: selection_size,
    empty: selection_empty,
    each: selection_each,
    attr: selection_attr,
    style: selection_style,
    property: selection_property,
    classed: selection_classed,
    text: selection_text,
    html: selection_html,
    raise: selection_raise,
    lower: selection_lower,
    append: selection_append,
    insert: selection_insert,
    remove: selection_remove,
    clone: selection_clone,
    datum: selection_datum,
    on: selection_on,
    dispatch: selection_dispatch
  };

  function d3Select(selector) {
    return typeof selector === "string"
        ? new Selection([[document.querySelector(selector)]], [document.documentElement])
        : new Selection([[selector]], root);
  }

  function sourceEvent() {
    var current = event, source;
    while (source = current.sourceEvent) current = source;
    return current;
  }

  function point(node, event) {
    var svg = node.ownerSVGElement || node;

    if (svg.createSVGPoint) {
      var point = svg.createSVGPoint();
      point.x = event.clientX, point.y = event.clientY;
      point = point.matrixTransform(node.getScreenCTM().inverse());
      return [point.x, point.y];
    }

    var rect = node.getBoundingClientRect();
    return [event.clientX - rect.left - node.clientLeft, event.clientY - rect.top - node.clientTop];
  }

  function mouse(node) {
    var event = sourceEvent();
    if (event.changedTouches) event = event.changedTouches[0];
    return point(node, event);
  }

  function touch(node, touches, identifier) {
    if (arguments.length < 3) identifier = touches, touches = sourceEvent().changedTouches;

    for (var i = 0, n = touches ? touches.length : 0, touch; i < n; ++i) {
      if ((touch = touches[i]).identifier === identifier) {
        return point(node, touch);
      }
    }

    return null;
  }

  var noop = {value: function() {}};

  function dispatch() {
    for (var i = 0, n = arguments.length, _ = {}, t; i < n; ++i) {
      if (!(t = arguments[i] + "") || (t in _)) throw new Error("illegal type: " + t);
      _[t] = [];
    }
    return new Dispatch(_);
  }

  function Dispatch(_) {
    this._ = _;
  }

  function parseTypenames$1(typenames, types) {
    return typenames.trim().split(/^|\s+/).map(function(t) {
      var name = "", i = t.indexOf(".");
      if (i >= 0) name = t.slice(i + 1), t = t.slice(0, i);
      if (t && !types.hasOwnProperty(t)) throw new Error("unknown type: " + t);
      return {type: t, name: name};
    });
  }

  Dispatch.prototype = dispatch.prototype = {
    constructor: Dispatch,
    on: function(typename, callback) {
      var _ = this._,
          T = parseTypenames$1(typename + "", _),
          t,
          i = -1,
          n = T.length;

      // If no callback was specified, return the callback of the given type and name.
      if (arguments.length < 2) {
        while (++i < n) if ((t = (typename = T[i]).type) && (t = get(_[t], typename.name))) return t;
        return;
      }

      // If a type was specified, set the callback for the given type and name.
      // Otherwise, if a null callback was specified, remove callbacks of the given name.
      if (callback != null && typeof callback !== "function") throw new Error("invalid callback: " + callback);
      while (++i < n) {
        if (t = (typename = T[i]).type) _[t] = set(_[t], typename.name, callback);
        else if (callback == null) for (t in _) _[t] = set(_[t], typename.name, null);
      }

      return this;
    },
    copy: function() {
      var copy = {}, _ = this._;
      for (var t in _) copy[t] = _[t].slice();
      return new Dispatch(copy);
    },
    call: function(type, that) {
      if ((n = arguments.length - 2) > 0) for (var args = new Array(n), i = 0, n, t; i < n; ++i) args[i] = arguments[i + 2];
      if (!this._.hasOwnProperty(type)) throw new Error("unknown type: " + type);
      for (t = this._[type], i = 0, n = t.length; i < n; ++i) t[i].value.apply(that, args);
    },
    apply: function(type, that, args) {
      if (!this._.hasOwnProperty(type)) throw new Error("unknown type: " + type);
      for (var t = this._[type], i = 0, n = t.length; i < n; ++i) t[i].value.apply(that, args);
    }
  };

  function get(type, name) {
    for (var i = 0, n = type.length, c; i < n; ++i) {
      if ((c = type[i]).name === name) {
        return c.value;
      }
    }
  }

  function set(type, name, callback) {
    for (var i = 0, n = type.length; i < n; ++i) {
      if (type[i].name === name) {
        type[i] = noop, type = type.slice(0, i).concat(type.slice(i + 1));
        break;
      }
    }
    if (callback != null) type.push({name: name, value: callback});
    return type;
  }

  var frame = 0, // is an animation frame pending?
      timeout = 0, // is a timeout pending?
      interval = 0, // are any timers active?
      pokeDelay = 1000, // how frequently we check for clock skew
      taskHead,
      taskTail,
      clockLast = 0,
      clockNow = 0,
      clockSkew = 0,
      clock = typeof performance === "object" && performance.now ? performance : Date,
      setFrame = typeof window === "object" && window.requestAnimationFrame ? window.requestAnimationFrame.bind(window) : function(f) { setTimeout(f, 17); };

  function now() {
    return clockNow || (setFrame(clearNow), clockNow = clock.now() + clockSkew);
  }

  function clearNow() {
    clockNow = 0;
  }

  function Timer() {
    this._call =
    this._time =
    this._next = null;
  }

  Timer.prototype = timer.prototype = {
    constructor: Timer,
    restart: function(callback, delay, time) {
      if (typeof callback !== "function") throw new TypeError("callback is not a function");
      time = (time == null ? now() : +time) + (delay == null ? 0 : +delay);
      if (!this._next && taskTail !== this) {
        if (taskTail) taskTail._next = this;
        else taskHead = this;
        taskTail = this;
      }
      this._call = callback;
      this._time = time;
      sleep();
    },
    stop: function() {
      if (this._call) {
        this._call = null;
        this._time = Infinity;
        sleep();
      }
    }
  };

  function timer(callback, delay, time) {
    var t = new Timer;
    t.restart(callback, delay, time);
    return t;
  }

  function timerFlush() {
    now(); // Get the current time, if not already set.
    ++frame; // Pretend we’ve set an alarm, if we haven’t already.
    var t = taskHead, e;
    while (t) {
      if ((e = clockNow - t._time) >= 0) t._call.call(null, e);
      t = t._next;
    }
    --frame;
  }

  function wake() {
    clockNow = (clockLast = clock.now()) + clockSkew;
    frame = timeout = 0;
    try {
      timerFlush();
    } finally {
      frame = 0;
      nap();
      clockNow = 0;
    }
  }

  function poke() {
    var now = clock.now(), delay = now - clockLast;
    if (delay > pokeDelay) clockSkew -= delay, clockLast = now;
  }

  function nap() {
    var t0, t1 = taskHead, t2, time = Infinity;
    while (t1) {
      if (t1._call) {
        if (time > t1._time) time = t1._time;
        t0 = t1, t1 = t1._next;
      } else {
        t2 = t1._next, t1._next = null;
        t1 = t0 ? t0._next = t2 : taskHead = t2;
      }
    }
    taskTail = t0;
    sleep(time);
  }

  function sleep(time) {
    if (frame) return; // Soonest alarm already set, or will be.
    if (timeout) timeout = clearTimeout(timeout);
    var delay = time - clockNow; // Strictly less than if we recomputed clockNow.
    if (delay > 24) {
      if (time < Infinity) timeout = setTimeout(wake, time - clock.now() - clockSkew);
      if (interval) interval = clearInterval(interval);
    } else {
      if (!interval) clockLast = clock.now(), interval = setInterval(poke, pokeDelay);
      frame = 1, setFrame(wake);
    }
  }

  function timeout$1(callback, delay, time) {
    var t = new Timer;
    delay = delay == null ? 0 : +delay;
    t.restart(function(elapsed) {
      t.stop();
      callback(elapsed + delay);
    }, delay, time);
    return t;
  }

  var emptyOn = dispatch("start", "end", "cancel", "interrupt");
  var emptyTween = [];

  var CREATED = 0;
  var SCHEDULED = 1;
  var STARTING = 2;
  var STARTED = 3;
  var RUNNING = 4;
  var ENDING = 5;
  var ENDED = 6;

  function schedule(node, name, id, index, group, timing) {
    var schedules = node.__transition;
    if (!schedules) node.__transition = {};
    else if (id in schedules) return;
    create(node, id, {
      name: name,
      index: index, // For context during callback.
      group: group, // For context during callback.
      on: emptyOn,
      tween: emptyTween,
      time: timing.time,
      delay: timing.delay,
      duration: timing.duration,
      ease: timing.ease,
      timer: null,
      state: CREATED
    });
  }

  function init(node, id) {
    var schedule = get$1(node, id);
    if (schedule.state > CREATED) throw new Error("too late; already scheduled");
    return schedule;
  }

  function set$1(node, id) {
    var schedule = get$1(node, id);
    if (schedule.state > STARTED) throw new Error("too late; already running");
    return schedule;
  }

  function get$1(node, id) {
    var schedule = node.__transition;
    if (!schedule || !(schedule = schedule[id])) throw new Error("transition not found");
    return schedule;
  }

  function create(node, id, self) {
    var schedules = node.__transition,
        tween;

    // Initialize the self timer when the transition is created.
    // Note the actual delay is not known until the first callback!
    schedules[id] = self;
    self.timer = timer(schedule, 0, self.time);

    function schedule(elapsed) {
      self.state = SCHEDULED;
      self.timer.restart(start, self.delay, self.time);

      // If the elapsed delay is less than our first sleep, start immediately.
      if (self.delay <= elapsed) start(elapsed - self.delay);
    }

    function start(elapsed) {
      var i, j, n, o;

      // If the state is not SCHEDULED, then we previously errored on start.
      if (self.state !== SCHEDULED) return stop();

      for (i in schedules) {
        o = schedules[i];
        if (o.name !== self.name) continue;

        // While this element already has a starting transition during this frame,
        // defer starting an interrupting transition until that transition has a
        // chance to tick (and possibly end); see d3/d3-transition#54!
        if (o.state === STARTED) return timeout$1(start);

        // Interrupt the active transition, if any.
        if (o.state === RUNNING) {
          o.state = ENDED;
          o.timer.stop();
          o.on.call("interrupt", node, node.__data__, o.index, o.group);
          delete schedules[i];
        }

        // Cancel any pre-empted transitions.
        else if (+i < id) {
          o.state = ENDED;
          o.timer.stop();
          o.on.call("cancel", node, node.__data__, o.index, o.group);
          delete schedules[i];
        }
      }

      // Defer the first tick to end of the current frame; see d3/d3#1576.
      // Note the transition may be canceled after start and before the first tick!
      // Note this must be scheduled before the start event; see d3/d3-transition#16!
      // Assuming this is successful, subsequent callbacks go straight to tick.
      timeout$1(function() {
        if (self.state === STARTED) {
          self.state = RUNNING;
          self.timer.restart(tick, self.delay, self.time);
          tick(elapsed);
        }
      });

      // Dispatch the start event.
      // Note this must be done before the tween are initialized.
      self.state = STARTING;
      self.on.call("start", node, node.__data__, self.index, self.group);
      if (self.state !== STARTING) return; // interrupted
      self.state = STARTED;

      // Initialize the tween, deleting null tween.
      tween = new Array(n = self.tween.length);
      for (i = 0, j = -1; i < n; ++i) {
        if (o = self.tween[i].value.call(node, node.__data__, self.index, self.group)) {
          tween[++j] = o;
        }
      }
      tween.length = j + 1;
    }

    function tick(elapsed) {
      var t = elapsed < self.duration ? self.ease.call(null, elapsed / self.duration) : (self.timer.restart(stop), self.state = ENDING, 1),
          i = -1,
          n = tween.length;

      while (++i < n) {
        tween[i].call(node, t);
      }

      // Dispatch the end event.
      if (self.state === ENDING) {
        self.on.call("end", node, node.__data__, self.index, self.group);
        stop();
      }
    }

    function stop() {
      self.state = ENDED;
      self.timer.stop();
      delete schedules[id];
      for (var i in schedules) return; // eslint-disable-line no-unused-vars
      delete node.__transition;
    }
  }

  function interrupt(node, name) {
    var schedules = node.__transition,
        schedule,
        active,
        empty = true,
        i;

    if (!schedules) return;

    name = name == null ? null : name + "";

    for (i in schedules) {
      if ((schedule = schedules[i]).name !== name) { empty = false; continue; }
      active = schedule.state > STARTING && schedule.state < ENDING;
      schedule.state = ENDED;
      schedule.timer.stop();
      schedule.on.call(active ? "interrupt" : "cancel", node, node.__data__, schedule.index, schedule.group);
      delete schedules[i];
    }

    if (empty) delete node.__transition;
  }

  function selection_interrupt(name) {
    return this.each(function() {
      interrupt(this, name);
    });
  }

  function define(constructor, factory, prototype) {
    constructor.prototype = factory.prototype = prototype;
    prototype.constructor = constructor;
  }

  function extend(parent, definition) {
    var prototype = Object.create(parent.prototype);
    for (var key in definition) prototype[key] = definition[key];
    return prototype;
  }

  function Color() {}

  var darker = 0.7;
  var brighter = 1 / darker;

  var reI = "\\s*([+-]?\\d+)\\s*",
      reN = "\\s*([+-]?\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)\\s*",
      reP = "\\s*([+-]?\\d*\\.?\\d+(?:[eE][+-]?\\d+)?)%\\s*",
      reHex3 = /^#([0-9a-f]{3})$/,
      reHex6 = /^#([0-9a-f]{6})$/,
      reRgbInteger = new RegExp("^rgb\\(" + [reI, reI, reI] + "\\)$"),
      reRgbPercent = new RegExp("^rgb\\(" + [reP, reP, reP] + "\\)$"),
      reRgbaInteger = new RegExp("^rgba\\(" + [reI, reI, reI, reN] + "\\)$"),
      reRgbaPercent = new RegExp("^rgba\\(" + [reP, reP, reP, reN] + "\\)$"),
      reHslPercent = new RegExp("^hsl\\(" + [reN, reP, reP] + "\\)$"),
      reHslaPercent = new RegExp("^hsla\\(" + [reN, reP, reP, reN] + "\\)$");

  var named = {
    aliceblue: 0xf0f8ff,
    antiquewhite: 0xfaebd7,
    aqua: 0x00ffff,
    aquamarine: 0x7fffd4,
    azure: 0xf0ffff,
    beige: 0xf5f5dc,
    bisque: 0xffe4c4,
    black: 0x000000,
    blanchedalmond: 0xffebcd,
    blue: 0x0000ff,
    blueviolet: 0x8a2be2,
    brown: 0xa52a2a,
    burlywood: 0xdeb887,
    cadetblue: 0x5f9ea0,
    chartreuse: 0x7fff00,
    chocolate: 0xd2691e,
    coral: 0xff7f50,
    cornflowerblue: 0x6495ed,
    cornsilk: 0xfff8dc,
    crimson: 0xdc143c,
    cyan: 0x00ffff,
    darkblue: 0x00008b,
    darkcyan: 0x008b8b,
    darkgoldenrod: 0xb8860b,
    darkgray: 0xa9a9a9,
    darkgreen: 0x006400,
    darkgrey: 0xa9a9a9,
    darkkhaki: 0xbdb76b,
    darkmagenta: 0x8b008b,
    darkolivegreen: 0x556b2f,
    darkorange: 0xff8c00,
    darkorchid: 0x9932cc,
    darkred: 0x8b0000,
    darksalmon: 0xe9967a,
    darkseagreen: 0x8fbc8f,
    darkslateblue: 0x483d8b,
    darkslategray: 0x2f4f4f,
    darkslategrey: 0x2f4f4f,
    darkturquoise: 0x00ced1,
    darkviolet: 0x9400d3,
    deeppink: 0xff1493,
    deepskyblue: 0x00bfff,
    dimgray: 0x696969,
    dimgrey: 0x696969,
    dodgerblue: 0x1e90ff,
    firebrick: 0xb22222,
    floralwhite: 0xfffaf0,
    forestgreen: 0x228b22,
    fuchsia: 0xff00ff,
    gainsboro: 0xdcdcdc,
    ghostwhite: 0xf8f8ff,
    gold: 0xffd700,
    goldenrod: 0xdaa520,
    gray: 0x808080,
    green: 0x008000,
    greenyellow: 0xadff2f,
    grey: 0x808080,
    honeydew: 0xf0fff0,
    hotpink: 0xff69b4,
    indianred: 0xcd5c5c,
    indigo: 0x4b0082,
    ivory: 0xfffff0,
    khaki: 0xf0e68c,
    lavender: 0xe6e6fa,
    lavenderblush: 0xfff0f5,
    lawngreen: 0x7cfc00,
    lemonchiffon: 0xfffacd,
    lightblue: 0xadd8e6,
    lightcoral: 0xf08080,
    lightcyan: 0xe0ffff,
    lightgoldenrodyellow: 0xfafad2,
    lightgray: 0xd3d3d3,
    lightgreen: 0x90ee90,
    lightgrey: 0xd3d3d3,
    lightpink: 0xffb6c1,
    lightsalmon: 0xffa07a,
    lightseagreen: 0x20b2aa,
    lightskyblue: 0x87cefa,
    lightslategray: 0x778899,
    lightslategrey: 0x778899,
    lightsteelblue: 0xb0c4de,
    lightyellow: 0xffffe0,
    lime: 0x00ff00,
    limegreen: 0x32cd32,
    linen: 0xfaf0e6,
    magenta: 0xff00ff,
    maroon: 0x800000,
    mediumaquamarine: 0x66cdaa,
    mediumblue: 0x0000cd,
    mediumorchid: 0xba55d3,
    mediumpurple: 0x9370db,
    mediumseagreen: 0x3cb371,
    mediumslateblue: 0x7b68ee,
    mediumspringgreen: 0x00fa9a,
    mediumturquoise: 0x48d1cc,
    mediumvioletred: 0xc71585,
    midnightblue: 0x191970,
    mintcream: 0xf5fffa,
    mistyrose: 0xffe4e1,
    moccasin: 0xffe4b5,
    navajowhite: 0xffdead,
    navy: 0x000080,
    oldlace: 0xfdf5e6,
    olive: 0x808000,
    olivedrab: 0x6b8e23,
    orange: 0xffa500,
    orangered: 0xff4500,
    orchid: 0xda70d6,
    palegoldenrod: 0xeee8aa,
    palegreen: 0x98fb98,
    paleturquoise: 0xafeeee,
    palevioletred: 0xdb7093,
    papayawhip: 0xffefd5,
    peachpuff: 0xffdab9,
    peru: 0xcd853f,
    pink: 0xffc0cb,
    plum: 0xdda0dd,
    powderblue: 0xb0e0e6,
    purple: 0x800080,
    rebeccapurple: 0x663399,
    red: 0xff0000,
    rosybrown: 0xbc8f8f,
    royalblue: 0x4169e1,
    saddlebrown: 0x8b4513,
    salmon: 0xfa8072,
    sandybrown: 0xf4a460,
    seagreen: 0x2e8b57,
    seashell: 0xfff5ee,
    sienna: 0xa0522d,
    silver: 0xc0c0c0,
    skyblue: 0x87ceeb,
    slateblue: 0x6a5acd,
    slategray: 0x708090,
    slategrey: 0x708090,
    snow: 0xfffafa,
    springgreen: 0x00ff7f,
    steelblue: 0x4682b4,
    tan: 0xd2b48c,
    teal: 0x008080,
    thistle: 0xd8bfd8,
    tomato: 0xff6347,
    turquoise: 0x40e0d0,
    violet: 0xee82ee,
    wheat: 0xf5deb3,
    white: 0xffffff,
    whitesmoke: 0xf5f5f5,
    yellow: 0xffff00,
    yellowgreen: 0x9acd32
  };

  define(Color, color, {
    displayable: function() {
      return this.rgb().displayable();
    },
    hex: function() {
      return this.rgb().hex();
    },
    toString: function() {
      return this.rgb() + "";
    }
  });

  function color(format) {
    var m;
    format = (format + "").trim().toLowerCase();
    return (m = reHex3.exec(format)) ? (m = parseInt(m[1], 16), new Rgb((m >> 8 & 0xf) | (m >> 4 & 0x0f0), (m >> 4 & 0xf) | (m & 0xf0), ((m & 0xf) << 4) | (m & 0xf), 1)) // #f00
        : (m = reHex6.exec(format)) ? rgbn(parseInt(m[1], 16)) // #ff0000
        : (m = reRgbInteger.exec(format)) ? new Rgb(m[1], m[2], m[3], 1) // rgb(255, 0, 0)
        : (m = reRgbPercent.exec(format)) ? new Rgb(m[1] * 255 / 100, m[2] * 255 / 100, m[3] * 255 / 100, 1) // rgb(100%, 0%, 0%)
        : (m = reRgbaInteger.exec(format)) ? rgba(m[1], m[2], m[3], m[4]) // rgba(255, 0, 0, 1)
        : (m = reRgbaPercent.exec(format)) ? rgba(m[1] * 255 / 100, m[2] * 255 / 100, m[3] * 255 / 100, m[4]) // rgb(100%, 0%, 0%, 1)
        : (m = reHslPercent.exec(format)) ? hsla(m[1], m[2] / 100, m[3] / 100, 1) // hsl(120, 50%, 50%)
        : (m = reHslaPercent.exec(format)) ? hsla(m[1], m[2] / 100, m[3] / 100, m[4]) // hsla(120, 50%, 50%, 1)
        : named.hasOwnProperty(format) ? rgbn(named[format])
        : format === "transparent" ? new Rgb(NaN, NaN, NaN, 0)
        : null;
  }

  function rgbn(n) {
    return new Rgb(n >> 16 & 0xff, n >> 8 & 0xff, n & 0xff, 1);
  }

  function rgba(r, g, b, a) {
    if (a <= 0) r = g = b = NaN;
    return new Rgb(r, g, b, a);
  }

  function rgbConvert(o) {
    if (!(o instanceof Color)) o = color(o);
    if (!o) return new Rgb;
    o = o.rgb();
    return new Rgb(o.r, o.g, o.b, o.opacity);
  }

  function rgb(r, g, b, opacity) {
    return arguments.length === 1 ? rgbConvert(r) : new Rgb(r, g, b, opacity == null ? 1 : opacity);
  }

  function Rgb(r, g, b, opacity) {
    this.r = +r;
    this.g = +g;
    this.b = +b;
    this.opacity = +opacity;
  }

  define(Rgb, rgb, extend(Color, {
    brighter: function(k) {
      k = k == null ? brighter : Math.pow(brighter, k);
      return new Rgb(this.r * k, this.g * k, this.b * k, this.opacity);
    },
    darker: function(k) {
      k = k == null ? darker : Math.pow(darker, k);
      return new Rgb(this.r * k, this.g * k, this.b * k, this.opacity);
    },
    rgb: function() {
      return this;
    },
    displayable: function() {
      return (0 <= this.r && this.r <= 255)
          && (0 <= this.g && this.g <= 255)
          && (0 <= this.b && this.b <= 255)
          && (0 <= this.opacity && this.opacity <= 1);
    },
    hex: function() {
      return "#" + hex(this.r) + hex(this.g) + hex(this.b);
    },
    toString: function() {
      var a = this.opacity; a = isNaN(a) ? 1 : Math.max(0, Math.min(1, a));
      return (a === 1 ? "rgb(" : "rgba(")
          + Math.max(0, Math.min(255, Math.round(this.r) || 0)) + ", "
          + Math.max(0, Math.min(255, Math.round(this.g) || 0)) + ", "
          + Math.max(0, Math.min(255, Math.round(this.b) || 0))
          + (a === 1 ? ")" : ", " + a + ")");
    }
  }));

  function hex(value) {
    value = Math.max(0, Math.min(255, Math.round(value) || 0));
    return (value < 16 ? "0" : "") + value.toString(16);
  }

  function hsla(h, s, l, a) {
    if (a <= 0) h = s = l = NaN;
    else if (l <= 0 || l >= 1) h = s = NaN;
    else if (s <= 0) h = NaN;
    return new Hsl(h, s, l, a);
  }

  function hslConvert(o) {
    if (o instanceof Hsl) return new Hsl(o.h, o.s, o.l, o.opacity);
    if (!(o instanceof Color)) o = color(o);
    if (!o) return new Hsl;
    if (o instanceof Hsl) return o;
    o = o.rgb();
    var r = o.r / 255,
        g = o.g / 255,
        b = o.b / 255,
        min = Math.min(r, g, b),
        max = Math.max(r, g, b),
        h = NaN,
        s = max - min,
        l = (max + min) / 2;
    if (s) {
      if (r === max) h = (g - b) / s + (g < b) * 6;
      else if (g === max) h = (b - r) / s + 2;
      else h = (r - g) / s + 4;
      s /= l < 0.5 ? max + min : 2 - max - min;
      h *= 60;
    } else {
      s = l > 0 && l < 1 ? 0 : h;
    }
    return new Hsl(h, s, l, o.opacity);
  }

  function hsl(h, s, l, opacity) {
    return arguments.length === 1 ? hslConvert(h) : new Hsl(h, s, l, opacity == null ? 1 : opacity);
  }

  function Hsl(h, s, l, opacity) {
    this.h = +h;
    this.s = +s;
    this.l = +l;
    this.opacity = +opacity;
  }

  define(Hsl, hsl, extend(Color, {
    brighter: function(k) {
      k = k == null ? brighter : Math.pow(brighter, k);
      return new Hsl(this.h, this.s, this.l * k, this.opacity);
    },
    darker: function(k) {
      k = k == null ? darker : Math.pow(darker, k);
      return new Hsl(this.h, this.s, this.l * k, this.opacity);
    },
    rgb: function() {
      var h = this.h % 360 + (this.h < 0) * 360,
          s = isNaN(h) || isNaN(this.s) ? 0 : this.s,
          l = this.l,
          m2 = l + (l < 0.5 ? l : 1 - l) * s,
          m1 = 2 * l - m2;
      return new Rgb(
        hsl2rgb(h >= 240 ? h - 240 : h + 120, m1, m2),
        hsl2rgb(h, m1, m2),
        hsl2rgb(h < 120 ? h + 240 : h - 120, m1, m2),
        this.opacity
      );
    },
    displayable: function() {
      return (0 <= this.s && this.s <= 1 || isNaN(this.s))
          && (0 <= this.l && this.l <= 1)
          && (0 <= this.opacity && this.opacity <= 1);
    }
  }));

  /* From FvD 13.37, CSS Color Module Level 3 */
  function hsl2rgb(h, m1, m2) {
    return (h < 60 ? m1 + (m2 - m1) * h / 60
        : h < 180 ? m2
        : h < 240 ? m1 + (m2 - m1) * (240 - h) / 60
        : m1) * 255;
  }

  var deg2rad = Math.PI / 180;
  var rad2deg = 180 / Math.PI;

  // https://beta.observablehq.com/@mbostock/lab-and-rgb
  var K = 18,
      Xn = 0.96422,
      Yn = 1,
      Zn = 0.82521,
      t0 = 4 / 29,
      t1 = 6 / 29,
      t2 = 3 * t1 * t1,
      t3 = t1 * t1 * t1;

  function labConvert(o) {
    if (o instanceof Lab) return new Lab(o.l, o.a, o.b, o.opacity);
    if (o instanceof Hcl) {
      if (isNaN(o.h)) return new Lab(o.l, 0, 0, o.opacity);
      var h = o.h * deg2rad;
      return new Lab(o.l, Math.cos(h) * o.c, Math.sin(h) * o.c, o.opacity);
    }
    if (!(o instanceof Rgb)) o = rgbConvert(o);
    var r = rgb2lrgb(o.r),
        g = rgb2lrgb(o.g),
        b = rgb2lrgb(o.b),
        y = xyz2lab((0.2225045 * r + 0.7168786 * g + 0.0606169 * b) / Yn), x, z;
    if (r === g && g === b) x = z = y; else {
      x = xyz2lab((0.4360747 * r + 0.3850649 * g + 0.1430804 * b) / Xn);
      z = xyz2lab((0.0139322 * r + 0.0971045 * g + 0.7141733 * b) / Zn);
    }
    return new Lab(116 * y - 16, 500 * (x - y), 200 * (y - z), o.opacity);
  }

  function lab(l, a, b, opacity) {
    return arguments.length === 1 ? labConvert(l) : new Lab(l, a, b, opacity == null ? 1 : opacity);
  }

  function Lab(l, a, b, opacity) {
    this.l = +l;
    this.a = +a;
    this.b = +b;
    this.opacity = +opacity;
  }

  define(Lab, lab, extend(Color, {
    brighter: function(k) {
      return new Lab(this.l + K * (k == null ? 1 : k), this.a, this.b, this.opacity);
    },
    darker: function(k) {
      return new Lab(this.l - K * (k == null ? 1 : k), this.a, this.b, this.opacity);
    },
    rgb: function() {
      var y = (this.l + 16) / 116,
          x = isNaN(this.a) ? y : y + this.a / 500,
          z = isNaN(this.b) ? y : y - this.b / 200;
      x = Xn * lab2xyz(x);
      y = Yn * lab2xyz(y);
      z = Zn * lab2xyz(z);
      return new Rgb(
        lrgb2rgb( 3.1338561 * x - 1.6168667 * y - 0.4906146 * z),
        lrgb2rgb(-0.9787684 * x + 1.9161415 * y + 0.0334540 * z),
        lrgb2rgb( 0.0719453 * x - 0.2289914 * y + 1.4052427 * z),
        this.opacity
      );
    }
  }));

  function xyz2lab(t) {
    return t > t3 ? Math.pow(t, 1 / 3) : t / t2 + t0;
  }

  function lab2xyz(t) {
    return t > t1 ? t * t * t : t2 * (t - t0);
  }

  function lrgb2rgb(x) {
    return 255 * (x <= 0.0031308 ? 12.92 * x : 1.055 * Math.pow(x, 1 / 2.4) - 0.055);
  }

  function rgb2lrgb(x) {
    return (x /= 255) <= 0.04045 ? x / 12.92 : Math.pow((x + 0.055) / 1.055, 2.4);
  }

  function hclConvert(o) {
    if (o instanceof Hcl) return new Hcl(o.h, o.c, o.l, o.opacity);
    if (!(o instanceof Lab)) o = labConvert(o);
    if (o.a === 0 && o.b === 0) return new Hcl(NaN, 0, o.l, o.opacity);
    var h = Math.atan2(o.b, o.a) * rad2deg;
    return new Hcl(h < 0 ? h + 360 : h, Math.sqrt(o.a * o.a + o.b * o.b), o.l, o.opacity);
  }

  function hcl(h, c, l, opacity) {
    return arguments.length === 1 ? hclConvert(h) : new Hcl(h, c, l, opacity == null ? 1 : opacity);
  }

  function Hcl(h, c, l, opacity) {
    this.h = +h;
    this.c = +c;
    this.l = +l;
    this.opacity = +opacity;
  }

  define(Hcl, hcl, extend(Color, {
    brighter: function(k) {
      return new Hcl(this.h, this.c, this.l + K * (k == null ? 1 : k), this.opacity);
    },
    darker: function(k) {
      return new Hcl(this.h, this.c, this.l - K * (k == null ? 1 : k), this.opacity);
    },
    rgb: function() {
      return labConvert(this).rgb();
    }
  }));

  var A = -0.14861,
      B = +1.78277,
      C = -0.29227,
      D = -0.90649,
      E = +1.97294,
      ED = E * D,
      EB = E * B,
      BC_DA = B * C - D * A;

  function cubehelixConvert(o) {
    if (o instanceof Cubehelix) return new Cubehelix(o.h, o.s, o.l, o.opacity);
    if (!(o instanceof Rgb)) o = rgbConvert(o);
    var r = o.r / 255,
        g = o.g / 255,
        b = o.b / 255,
        l = (BC_DA * b + ED * r - EB * g) / (BC_DA + ED - EB),
        bl = b - l,
        k = (E * (g - l) - C * bl) / D,
        s = Math.sqrt(k * k + bl * bl) / (E * l * (1 - l)), // NaN if l=0 or l=1
        h = s ? Math.atan2(k, bl) * rad2deg - 120 : NaN;
    return new Cubehelix(h < 0 ? h + 360 : h, s, l, o.opacity);
  }

  function cubehelix(h, s, l, opacity) {
    return arguments.length === 1 ? cubehelixConvert(h) : new Cubehelix(h, s, l, opacity == null ? 1 : opacity);
  }

  function Cubehelix(h, s, l, opacity) {
    this.h = +h;
    this.s = +s;
    this.l = +l;
    this.opacity = +opacity;
  }

  define(Cubehelix, cubehelix, extend(Color, {
    brighter: function(k) {
      k = k == null ? brighter : Math.pow(brighter, k);
      return new Cubehelix(this.h, this.s, this.l * k, this.opacity);
    },
    darker: function(k) {
      k = k == null ? darker : Math.pow(darker, k);
      return new Cubehelix(this.h, this.s, this.l * k, this.opacity);
    },
    rgb: function() {
      var h = isNaN(this.h) ? 0 : (this.h + 120) * deg2rad,
          l = +this.l,
          a = isNaN(this.s) ? 0 : this.s * l * (1 - l),
          cosh = Math.cos(h),
          sinh = Math.sin(h);
      return new Rgb(
        255 * (l + a * (A * cosh + B * sinh)),
        255 * (l + a * (C * cosh + D * sinh)),
        255 * (l + a * (E * cosh)),
        this.opacity
      );
    }
  }));

  function constant$1(x) {
    return function() {
      return x;
    };
  }

  function linear(a, d) {
    return function(t) {
      return a + t * d;
    };
  }

  function exponential(a, b, y) {
    return a = Math.pow(a, y), b = Math.pow(b, y) - a, y = 1 / y, function(t) {
      return Math.pow(a + t * b, y);
    };
  }

  function gamma(y) {
    return (y = +y) === 1 ? nogamma : function(a, b) {
      return b - a ? exponential(a, b, y) : constant$1(isNaN(a) ? b : a);
    };
  }

  function nogamma(a, b) {
    var d = b - a;
    return d ? linear(a, d) : constant$1(isNaN(a) ? b : a);
  }

  var interpolateRgb = (function rgbGamma(y) {
    var color = gamma(y);

    function rgb$1(start, end) {
      var r = color((start = rgb(start)).r, (end = rgb(end)).r),
          g = color(start.g, end.g),
          b = color(start.b, end.b),
          opacity = nogamma(start.opacity, end.opacity);
      return function(t) {
        start.r = r(t);
        start.g = g(t);
        start.b = b(t);
        start.opacity = opacity(t);
        return start + "";
      };
    }

    rgb$1.gamma = rgbGamma;

    return rgb$1;
  })(1);

  function d3InterpolateNumber(a, b) {
    return a = +a, b -= a, function(t) {
      return a + b * t;
    };
  }

  var reA = /[-+]?(?:\d+\.?\d*|\.?\d+)(?:[eE][-+]?\d+)?/g,
      reB = new RegExp(reA.source, "g");

  function zero(b) {
    return function() {
      return b;
    };
  }

  function one(b) {
    return function(t) {
      return b(t) + "";
    };
  }

  function interpolateString(a, b) {
    var bi = reA.lastIndex = reB.lastIndex = 0, // scan index for next number in b
        am, // current match in a
        bm, // current match in b
        bs, // string preceding current number in b, if any
        i = -1, // index in s
        s = [], // string constants and placeholders
        q = []; // number interpolators

    // Coerce inputs to strings.
    a = a + "", b = b + "";

    // Interpolate pairs of numbers in a & b.
    while ((am = reA.exec(a))
        && (bm = reB.exec(b))) {
      if ((bs = bm.index) > bi) { // a string precedes the next number in b
        bs = b.slice(bi, bs);
        if (s[i]) s[i] += bs; // coalesce with previous string
        else s[++i] = bs;
      }
      if ((am = am[0]) === (bm = bm[0])) { // numbers in a & b match
        if (s[i]) s[i] += bm; // coalesce with previous string
        else s[++i] = bm;
      } else { // interpolate non-matching numbers
        s[++i] = null;
        q.push({i: i, x: d3InterpolateNumber(am, bm)});
      }
      bi = reB.lastIndex;
    }

    // Add remains of b.
    if (bi < b.length) {
      bs = b.slice(bi);
      if (s[i]) s[i] += bs; // coalesce with previous string
      else s[++i] = bs;
    }

    // Special optimization for only a single match.
    // Otherwise, interpolate each of the numbers and rejoin the string.
    return s.length < 2 ? (q[0]
        ? one(q[0].x)
        : zero(b))
        : (b = q.length, function(t) {
            for (var i = 0, o; i < b; ++i) s[(o = q[i]).i] = o.x(t);
            return s.join("");
          });
  }

  var degrees = 180 / Math.PI;

  var identity = {
    translateX: 0,
    translateY: 0,
    rotate: 0,
    skewX: 0,
    scaleX: 1,
    scaleY: 1
  };

  function decompose(a, b, c, d, e, f) {
    var scaleX, scaleY, skewX;
    if (scaleX = Math.sqrt(a * a + b * b)) a /= scaleX, b /= scaleX;
    if (skewX = a * c + b * d) c -= a * skewX, d -= b * skewX;
    if (scaleY = Math.sqrt(c * c + d * d)) c /= scaleY, d /= scaleY, skewX /= scaleY;
    if (a * d < b * c) a = -a, b = -b, skewX = -skewX, scaleX = -scaleX;
    return {
      translateX: e,
      translateY: f,
      rotate: Math.atan2(b, a) * degrees,
      skewX: Math.atan(skewX) * degrees,
      scaleX: scaleX,
      scaleY: scaleY
    };
  }

  var cssNode,
      cssRoot,
      cssView,
      svgNode;

  function parseCss(value) {
    if (value === "none") return identity;
    if (!cssNode) cssNode = document.createElement("DIV"), cssRoot = document.documentElement, cssView = document.defaultView;
    cssNode.style.transform = value;
    value = cssView.getComputedStyle(cssRoot.appendChild(cssNode), null).getPropertyValue("transform");
    cssRoot.removeChild(cssNode);
    value = value.slice(7, -1).split(",");
    return decompose(+value[0], +value[1], +value[2], +value[3], +value[4], +value[5]);
  }

  function parseSvg(value) {
    if (value == null) return identity;
    if (!svgNode) svgNode = document.createElementNS("http://www.w3.org/2000/svg", "g");
    svgNode.setAttribute("transform", value);
    if (!(value = svgNode.transform.baseVal.consolidate())) return identity;
    value = value.matrix;
    return decompose(value.a, value.b, value.c, value.d, value.e, value.f);
  }

  function interpolateTransform(parse, pxComma, pxParen, degParen) {

    function pop(s) {
      return s.length ? s.pop() + " " : "";
    }

    function translate(xa, ya, xb, yb, s, q) {
      if (xa !== xb || ya !== yb) {
        var i = s.push("translate(", null, pxComma, null, pxParen);
        q.push({i: i - 4, x: d3InterpolateNumber(xa, xb)}, {i: i - 2, x: d3InterpolateNumber(ya, yb)});
      } else if (xb || yb) {
        s.push("translate(" + xb + pxComma + yb + pxParen);
      }
    }

    function rotate(a, b, s, q) {
      if (a !== b) {
        if (a - b > 180) b += 360; else if (b - a > 180) a += 360; // shortest path
        q.push({i: s.push(pop(s) + "rotate(", null, degParen) - 2, x: d3InterpolateNumber(a, b)});
      } else if (b) {
        s.push(pop(s) + "rotate(" + b + degParen);
      }
    }

    function skewX(a, b, s, q) {
      if (a !== b) {
        q.push({i: s.push(pop(s) + "skewX(", null, degParen) - 2, x: d3InterpolateNumber(a, b)});
      } else if (b) {
        s.push(pop(s) + "skewX(" + b + degParen);
      }
    }

    function scale(xa, ya, xb, yb, s, q) {
      if (xa !== xb || ya !== yb) {
        var i = s.push(pop(s) + "scale(", null, ",", null, ")");
        q.push({i: i - 4, x: d3InterpolateNumber(xa, xb)}, {i: i - 2, x: d3InterpolateNumber(ya, yb)});
      } else if (xb !== 1 || yb !== 1) {
        s.push(pop(s) + "scale(" + xb + "," + yb + ")");
      }
    }

    return function(a, b) {
      var s = [], // string constants and placeholders
          q = []; // number interpolators
      a = parse(a), b = parse(b);
      translate(a.translateX, a.translateY, b.translateX, b.translateY, s, q);
      rotate(a.rotate, b.rotate, s, q);
      skewX(a.skewX, b.skewX, s, q);
      scale(a.scaleX, a.scaleY, b.scaleX, b.scaleY, s, q);
      a = b = null; // gc
      return function(t) {
        var i = -1, n = q.length, o;
        while (++i < n) s[(o = q[i]).i] = o.x(t);
        return s.join("");
      };
    };
  }

  var interpolateTransformCss = interpolateTransform(parseCss, "px, ", "px)", "deg)");
  var interpolateTransformSvg = interpolateTransform(parseSvg, ", ", ")", ")");

  var rho = Math.SQRT2,
      rho2 = 2,
      rho4 = 4,
      epsilon2 = 1e-12;

  function cosh(x) {
    return ((x = Math.exp(x)) + 1 / x) / 2;
  }

  function sinh(x) {
    return ((x = Math.exp(x)) - 1 / x) / 2;
  }

  function tanh(x) {
    return ((x = Math.exp(2 * x)) - 1) / (x + 1);
  }

  // p0 = [ux0, uy0, w0]
  // p1 = [ux1, uy1, w1]
  function interpolateZoom(p0, p1) {
    var ux0 = p0[0], uy0 = p0[1], w0 = p0[2],
        ux1 = p1[0], uy1 = p1[1], w1 = p1[2],
        dx = ux1 - ux0,
        dy = uy1 - uy0,
        d2 = dx * dx + dy * dy,
        i,
        S;

    // Special case for u0 ≅ u1.
    if (d2 < epsilon2) {
      S = Math.log(w1 / w0) / rho;
      i = function(t) {
        return [
          ux0 + t * dx,
          uy0 + t * dy,
          w0 * Math.exp(rho * t * S)
        ];
      };
    }

    // General case.
    else {
      var d1 = Math.sqrt(d2),
          b0 = (w1 * w1 - w0 * w0 + rho4 * d2) / (2 * w0 * rho2 * d1),
          b1 = (w1 * w1 - w0 * w0 - rho4 * d2) / (2 * w1 * rho2 * d1),
          r0 = Math.log(Math.sqrt(b0 * b0 + 1) - b0),
          r1 = Math.log(Math.sqrt(b1 * b1 + 1) - b1);
      S = (r1 - r0) / rho;
      i = function(t) {
        var s = t * S,
            coshr0 = cosh(r0),
            u = w0 / (rho2 * d1) * (coshr0 * tanh(rho * s + r0) - sinh(r0));
        return [
          ux0 + u * dx,
          uy0 + u * dy,
          w0 * coshr0 / cosh(rho * s + r0)
        ];
      };
    }

    i.duration = S * 1000;

    return i;
  }

  function tweenRemove(id, name) {
    var tween0, tween1;
    return function() {
      var schedule = set$1(this, id),
          tween = schedule.tween;

      // If this node shared tween with the previous node,
      // just assign the updated shared tween and we’re done!
      // Otherwise, copy-on-write.
      if (tween !== tween0) {
        tween1 = tween0 = tween;
        for (var i = 0, n = tween1.length; i < n; ++i) {
          if (tween1[i].name === name) {
            tween1 = tween1.slice();
            tween1.splice(i, 1);
            break;
          }
        }
      }

      schedule.tween = tween1;
    };
  }

  function tweenFunction(id, name, value) {
    var tween0, tween1;
    if (typeof value !== "function") throw new Error;
    return function() {
      var schedule = set$1(this, id),
          tween = schedule.tween;

      // If this node shared tween with the previous node,
      // just assign the updated shared tween and we’re done!
      // Otherwise, copy-on-write.
      if (tween !== tween0) {
        tween1 = (tween0 = tween).slice();
        for (var t = {name: name, value: value}, i = 0, n = tween1.length; i < n; ++i) {
          if (tween1[i].name === name) {
            tween1[i] = t;
            break;
          }
        }
        if (i === n) tween1.push(t);
      }

      schedule.tween = tween1;
    };
  }

  function transition_tween(name, value) {
    var id = this._id;

    name += "";

    if (arguments.length < 2) {
      var tween = get$1(this.node(), id).tween;
      for (var i = 0, n = tween.length, t; i < n; ++i) {
        if ((t = tween[i]).name === name) {
          return t.value;
        }
      }
      return null;
    }

    return this.each((value == null ? tweenRemove : tweenFunction)(id, name, value));
  }

  function tweenValue(transition, name, value) {
    var id = transition._id;

    transition.each(function() {
      var schedule = set$1(this, id);
      (schedule.value || (schedule.value = {}))[name] = value.apply(this, arguments);
    });

    return function(node) {
      return get$1(node, id).value[name];
    };
  }

  function interpolate(a, b) {
    var c;
    return (typeof b === "number" ? d3InterpolateNumber
        : b instanceof color ? interpolateRgb
        : (c = color(b)) ? (b = c, interpolateRgb)
        : interpolateString)(a, b);
  }

  function attrRemove$1(name) {
    return function() {
      this.removeAttribute(name);
    };
  }

  function attrRemoveNS$1(fullname) {
    return function() {
      this.removeAttributeNS(fullname.space, fullname.local);
    };
  }

  function attrConstant$1(name, interpolate, value1) {
    var string00,
        string1 = value1 + "",
        interpolate0;
    return function() {
      var string0 = this.getAttribute(name);
      return string0 === string1 ? null
          : string0 === string00 ? interpolate0
          : interpolate0 = interpolate(string00 = string0, value1);
    };
  }

  function attrConstantNS$1(fullname, interpolate, value1) {
    var string00,
        string1 = value1 + "",
        interpolate0;
    return function() {
      var string0 = this.getAttributeNS(fullname.space, fullname.local);
      return string0 === string1 ? null
          : string0 === string00 ? interpolate0
          : interpolate0 = interpolate(string00 = string0, value1);
    };
  }

  function attrFunction$1(name, interpolate, value) {
    var string00,
        string10,
        interpolate0;
    return function() {
      var string0, value1 = value(this), string1;
      if (value1 == null) return void this.removeAttribute(name);
      string0 = this.getAttribute(name);
      string1 = value1 + "";
      return string0 === string1 ? null
          : string0 === string00 && string1 === string10 ? interpolate0
          : (string10 = string1, interpolate0 = interpolate(string00 = string0, value1));
    };
  }

  function attrFunctionNS$1(fullname, interpolate, value) {
    var string00,
        string10,
        interpolate0;
    return function() {
      var string0, value1 = value(this), string1;
      if (value1 == null) return void this.removeAttributeNS(fullname.space, fullname.local);
      string0 = this.getAttributeNS(fullname.space, fullname.local);
      string1 = value1 + "";
      return string0 === string1 ? null
          : string0 === string00 && string1 === string10 ? interpolate0
          : (string10 = string1, interpolate0 = interpolate(string00 = string0, value1));
    };
  }

  function transition_attr(name, value) {
    var fullname = namespace(name), i = fullname === "transform" ? interpolateTransformSvg : interpolate;
    return this.attrTween(name, typeof value === "function"
        ? (fullname.local ? attrFunctionNS$1 : attrFunction$1)(fullname, i, tweenValue(this, "attr." + name, value))
        : value == null ? (fullname.local ? attrRemoveNS$1 : attrRemove$1)(fullname)
        : (fullname.local ? attrConstantNS$1 : attrConstant$1)(fullname, i, value));
  }

  function attrInterpolate(name, i) {
    return function(t) {
      this.setAttribute(name, i(t));
    };
  }

  function attrInterpolateNS(fullname, i) {
    return function(t) {
      this.setAttributeNS(fullname.space, fullname.local, i(t));
    };
  }

  function attrTweenNS(fullname, value) {
    var t0, i0;
    function tween() {
      var i = value.apply(this, arguments);
      if (i !== i0) t0 = (i0 = i) && attrInterpolateNS(fullname, i);
      return t0;
    }
    tween._value = value;
    return tween;
  }

  function attrTween(name, value) {
    var t0, i0;
    function tween() {
      var i = value.apply(this, arguments);
      if (i !== i0) t0 = (i0 = i) && attrInterpolate(name, i);
      return t0;
    }
    tween._value = value;
    return tween;
  }

  function transition_attrTween(name, value) {
    var key = "attr." + name;
    if (arguments.length < 2) return (key = this.tween(key)) && key._value;
    if (value == null) return this.tween(key, null);
    if (typeof value !== "function") throw new Error;
    var fullname = namespace(name);
    return this.tween(key, (fullname.local ? attrTweenNS : attrTween)(fullname, value));
  }

  function delayFunction(id, value) {
    return function() {
      init(this, id).delay = +value.apply(this, arguments);
    };
  }

  function delayConstant(id, value) {
    return value = +value, function() {
      init(this, id).delay = value;
    };
  }

  function transition_delay(value) {
    var id = this._id;

    return arguments.length
        ? this.each((typeof value === "function"
            ? delayFunction
            : delayConstant)(id, value))
        : get$1(this.node(), id).delay;
  }

  function durationFunction(id, value) {
    return function() {
      set$1(this, id).duration = +value.apply(this, arguments);
    };
  }

  function durationConstant(id, value) {
    return value = +value, function() {
      set$1(this, id).duration = value;
    };
  }

  function transition_duration(value) {
    var id = this._id;

    return arguments.length
        ? this.each((typeof value === "function"
            ? durationFunction
            : durationConstant)(id, value))
        : get$1(this.node(), id).duration;
  }

  function easeConstant(id, value) {
    if (typeof value !== "function") throw new Error;
    return function() {
      set$1(this, id).ease = value;
    };
  }

  function transition_ease(value) {
    var id = this._id;

    return arguments.length
        ? this.each(easeConstant(id, value))
        : get$1(this.node(), id).ease;
  }

  function transition_filter(match) {
    if (typeof match !== "function") match = matcher(match);

    for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, subgroup = subgroups[j] = [], node, i = 0; i < n; ++i) {
        if ((node = group[i]) && match.call(node, node.__data__, i, group)) {
          subgroup.push(node);
        }
      }
    }

    return new Transition(subgroups, this._parents, this._name, this._id);
  }

  function transition_merge(transition) {
    if (transition._id !== this._id) throw new Error;

    for (var groups0 = this._groups, groups1 = transition._groups, m0 = groups0.length, m1 = groups1.length, m = Math.min(m0, m1), merges = new Array(m0), j = 0; j < m; ++j) {
      for (var group0 = groups0[j], group1 = groups1[j], n = group0.length, merge = merges[j] = new Array(n), node, i = 0; i < n; ++i) {
        if (node = group0[i] || group1[i]) {
          merge[i] = node;
        }
      }
    }

    for (; j < m0; ++j) {
      merges[j] = groups0[j];
    }

    return new Transition(merges, this._parents, this._name, this._id);
  }

  function start(name) {
    return (name + "").trim().split(/^|\s+/).every(function(t) {
      var i = t.indexOf(".");
      if (i >= 0) t = t.slice(0, i);
      return !t || t === "start";
    });
  }

  function onFunction(id, name, listener) {
    var on0, on1, sit = start(name) ? init : set$1;
    return function() {
      var schedule = sit(this, id),
          on = schedule.on;

      // If this node shared a dispatch with the previous node,
      // just assign the updated shared dispatch and we’re done!
      // Otherwise, copy-on-write.
      if (on !== on0) (on1 = (on0 = on).copy()).on(name, listener);

      schedule.on = on1;
    };
  }

  function transition_on(name, listener) {
    var id = this._id;

    return arguments.length < 2
        ? get$1(this.node(), id).on.on(name)
        : this.each(onFunction(id, name, listener));
  }

  function removeFunction(id) {
    return function() {
      var parent = this.parentNode;
      for (var i in this.__transition) if (+i !== id) return;
      if (parent) parent.removeChild(this);
    };
  }

  function transition_remove() {
    return this.on("end.remove", removeFunction(this._id));
  }

  function transition_select(select) {
    var name = this._name,
        id = this._id;

    if (typeof select !== "function") select = selector(select);

    for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, subgroup = subgroups[j] = new Array(n), node, subnode, i = 0; i < n; ++i) {
        if ((node = group[i]) && (subnode = select.call(node, node.__data__, i, group))) {
          if ("__data__" in node) subnode.__data__ = node.__data__;
          subgroup[i] = subnode;
          schedule(subgroup[i], name, id, i, subgroup, get$1(node, id));
        }
      }
    }

    return new Transition(subgroups, this._parents, name, id);
  }

  function transition_selectAll(select) {
    var name = this._name,
        id = this._id;

    if (typeof select !== "function") select = selectorAll(select);

    for (var groups = this._groups, m = groups.length, subgroups = [], parents = [], j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
        if (node = group[i]) {
          for (var children = select.call(node, node.__data__, i, group), child, inherit = get$1(node, id), k = 0, l = children.length; k < l; ++k) {
            if (child = children[k]) {
              schedule(child, name, id, k, children, inherit);
            }
          }
          subgroups.push(children);
          parents.push(node);
        }
      }
    }

    return new Transition(subgroups, parents, name, id);
  }

  var Selection$1 = selection.prototype.constructor;

  function transition_selection() {
    return new Selection$1(this._groups, this._parents);
  }

  function styleNull(name, interpolate) {
    var string00,
        string10,
        interpolate0;
    return function() {
      var string0 = styleValue(this, name),
          string1 = (this.style.removeProperty(name), styleValue(this, name));
      return string0 === string1 ? null
          : string0 === string00 && string1 === string10 ? interpolate0
          : interpolate0 = interpolate(string00 = string0, string10 = string1);
    };
  }

  function styleRemove$1(name) {
    return function() {
      this.style.removeProperty(name);
    };
  }

  function styleConstant$1(name, interpolate, value1) {
    var string00,
        string1 = value1 + "",
        interpolate0;
    return function() {
      var string0 = styleValue(this, name);
      return string0 === string1 ? null
          : string0 === string00 ? interpolate0
          : interpolate0 = interpolate(string00 = string0, value1);
    };
  }

  function styleFunction$1(name, interpolate, value) {
    var string00,
        string10,
        interpolate0;
    return function() {
      var string0 = styleValue(this, name),
          value1 = value(this),
          string1 = value1 + "";
      if (value1 == null) string1 = value1 = (this.style.removeProperty(name), styleValue(this, name));
      return string0 === string1 ? null
          : string0 === string00 && string1 === string10 ? interpolate0
          : (string10 = string1, interpolate0 = interpolate(string00 = string0, value1));
    };
  }

  function styleMaybeRemove(id, name) {
    var on0, on1, listener0, key = "style." + name, event = "end." + key, remove;
    return function() {
      var schedule = set$1(this, id),
          on = schedule.on,
          listener = schedule.value[key] == null ? remove || (remove = styleRemove$1(name)) : undefined;

      // If this node shared a dispatch with the previous node,
      // just assign the updated shared dispatch and we’re done!
      // Otherwise, copy-on-write.
      if (on !== on0 || listener0 !== listener) (on1 = (on0 = on).copy()).on(event, listener0 = listener);

      schedule.on = on1;
    };
  }

  function transition_style(name, value, priority) {
    var i = (name += "") === "transform" ? interpolateTransformCss : interpolate;
    return value == null ? this
        .styleTween(name, styleNull(name, i))
        .on("end.style." + name, styleRemove$1(name))
      : typeof value === "function" ? this
        .styleTween(name, styleFunction$1(name, i, tweenValue(this, "style." + name, value)))
        .each(styleMaybeRemove(this._id, name))
      : this
        .styleTween(name, styleConstant$1(name, i, value), priority)
        .on("end.style." + name, null);
  }

  function styleInterpolate(name, i, priority) {
    return function(t) {
      this.style.setProperty(name, i(t), priority);
    };
  }

  function styleTween(name, value, priority) {
    var t, i0;
    function tween() {
      var i = value.apply(this, arguments);
      if (i !== i0) t = (i0 = i) && styleInterpolate(name, i, priority);
      return t;
    }
    tween._value = value;
    return tween;
  }

  function transition_styleTween(name, value, priority) {
    var key = "style." + (name += "");
    if (arguments.length < 2) return (key = this.tween(key)) && key._value;
    if (value == null) return this.tween(key, null);
    if (typeof value !== "function") throw new Error;
    return this.tween(key, styleTween(name, value, priority == null ? "" : priority));
  }

  function textConstant$1(value) {
    return function() {
      this.textContent = value;
    };
  }

  function textFunction$1(value) {
    return function() {
      var value1 = value(this);
      this.textContent = value1 == null ? "" : value1;
    };
  }

  function transition_text(value) {
    return this.tween("text", typeof value === "function"
        ? textFunction$1(tweenValue(this, "text", value))
        : textConstant$1(value == null ? "" : value + ""));
  }

  function transition_transition() {
    var name = this._name,
        id0 = this._id,
        id1 = newId();

    for (var groups = this._groups, m = groups.length, j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
        if (node = group[i]) {
          var inherit = get$1(node, id0);
          schedule(node, name, id1, i, group, {
            time: inherit.time + inherit.delay + inherit.duration,
            delay: 0,
            duration: inherit.duration,
            ease: inherit.ease
          });
        }
      }
    }

    return new Transition(groups, this._parents, name, id1);
  }

  function transition_end() {
    var on0, on1, that = this, id = that._id, size = that.size();
    return new Promise(function(resolve, reject) {
      var cancel = {value: reject},
          end = {value: function() { if (--size === 0) resolve(); }};

      that.each(function() {
        var schedule = set$1(this, id),
            on = schedule.on;

        // If this node shared a dispatch with the previous node,
        // just assign the updated shared dispatch and we’re done!
        // Otherwise, copy-on-write.
        if (on !== on0) {
          on1 = (on0 = on).copy();
          on1._.cancel.push(cancel);
          on1._.interrupt.push(cancel);
          on1._.end.push(end);
        }

        schedule.on = on1;
      });
    });
  }

  var id = 0;

  function Transition(groups, parents, name, id) {
    this._groups = groups;
    this._parents = parents;
    this._name = name;
    this._id = id;
  }

  function transition(name) {
    return selection().transition(name);
  }

  function newId() {
    return ++id;
  }

  var selection_prototype = selection.prototype;

  Transition.prototype = transition.prototype = {
    constructor: Transition,
    select: transition_select,
    selectAll: transition_selectAll,
    filter: transition_filter,
    merge: transition_merge,
    selection: transition_selection,
    transition: transition_transition,
    call: selection_prototype.call,
    nodes: selection_prototype.nodes,
    node: selection_prototype.node,
    size: selection_prototype.size,
    empty: selection_prototype.empty,
    each: selection_prototype.each,
    on: transition_on,
    attr: transition_attr,
    attrTween: transition_attrTween,
    style: transition_style,
    styleTween: transition_styleTween,
    text: transition_text,
    remove: transition_remove,
    tween: transition_tween,
    delay: transition_delay,
    duration: transition_duration,
    ease: transition_ease,
    end: transition_end
  };

  function cubicInOut(t) {
    return ((t *= 2) <= 1 ? t * t * t : (t -= 2) * t * t + 2) / 2;
  }

  var pi = Math.PI;

  var tau = 2 * Math.PI;

  var defaultTiming = {
    time: null, // Set on use.
    delay: 0,
    duration: 250,
    ease: cubicInOut
  };

  function inherit(node, id) {
    var timing;
    while (!(timing = node.__transition) || !(timing = timing[id])) {
      if (!(node = node.parentNode)) {
        return defaultTiming.time = now(), defaultTiming;
      }
    }
    return timing;
  }

  function selection_transition(name) {
    var id,
        timing;

    if (name instanceof Transition) {
      id = name._id, name = name._name;
    } else {
      id = newId(), (timing = defaultTiming).time = now(), name = name == null ? null : name + "";
    }

    for (var groups = this._groups, m = groups.length, j = 0; j < m; ++j) {
      for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
        if (node = group[i]) {
          schedule(node, name, id, i, group, timing || inherit(node, id));
        }
      }
    }

    return new Transition(groups, this._parents, name, id);
  }

  selection.prototype.interrupt = selection_interrupt;
  selection.prototype.transition = selection_transition;

  function noevent() {
    event.preventDefault();
    event.stopImmediatePropagation();
  }

  function dragDisable(view) {
    var root = view.document.documentElement,
        selection = d3Select(view).on("dragstart.drag", noevent, true);
    if ("onselectstart" in root) {
      selection.on("selectstart.drag", noevent, true);
    } else {
      root.__noselect = root.style.MozUserSelect;
      root.style.MozUserSelect = "none";
    }
  }

  function yesdrag(view, noclick) {
    var root = view.document.documentElement,
        selection = d3Select(view).on("dragstart.drag", null);
    if (noclick) {
      selection.on("click.drag", noevent, true);
      setTimeout(function() { selection.on("click.drag", null); }, 0);
    }
    if ("onselectstart" in root) {
      selection.on("selectstart.drag", null);
    } else {
      root.style.MozUserSelect = root.__noselect;
      delete root.__noselect;
    }
  }

  function constant$2(x) {
    return function() {
      return x;
    };
  }

  function ZoomEvent(target, type, transform) {
    this.target = target;
    this.type = type;
    this.transform = transform;
  }

  function Transform(k, x, y) {
    this.k = k;
    this.x = x;
    this.y = y;
  }

  Transform.prototype = {
    constructor: Transform,
    scale: function(k) {
      return k === 1 ? this : new Transform(this.k * k, this.x, this.y);
    },
    translate: function(x, y) {
      return x === 0 & y === 0 ? this : new Transform(this.k, this.x + this.k * x, this.y + this.k * y);
    },
    apply: function(point) {
      return [point[0] * this.k + this.x, point[1] * this.k + this.y];
    },
    applyX: function(x) {
      return x * this.k + this.x;
    },
    applyY: function(y) {
      return y * this.k + this.y;
    },
    invert: function(location) {
      return [(location[0] - this.x) / this.k, (location[1] - this.y) / this.k];
    },
    invertX: function(x) {
      return (x - this.x) / this.k;
    },
    invertY: function(y) {
      return (y - this.y) / this.k;
    },
    rescaleX: function(x) {
      return x.copy().domain(x.range().map(this.invertX, this).map(x.invert, x));
    },
    rescaleY: function(y) {
      return y.copy().domain(y.range().map(this.invertY, this).map(y.invert, y));
    },
    toString: function() {
      return "translate(" + this.x + "," + this.y + ") scale(" + this.k + ")";
    }
  };

  var identity$1 = new Transform(1, 0, 0);

  function nopropagation() {
    event.stopImmediatePropagation();
  }

  function noevent$1() {
    event.preventDefault();
    event.stopImmediatePropagation();
  }

  // Ignore right-click, since that should open the context menu.
  function defaultFilter() {
    return !event.button;
  }

  function defaultExtent() {
    var e = this, w, h;
    if (e instanceof SVGElement) {
      e = e.ownerSVGElement || e;
      w = e.width.baseVal.value;
      h = e.height.baseVal.value;
    } else {
      w = e.clientWidth;
      h = e.clientHeight;
    }
    return [[0, 0], [w, h]];
  }

  function defaultTransform() {
    return this.__zoom || identity$1;
  }

  function defaultWheelDelta() {
    return -event.deltaY * (event.deltaMode ? 120 : 1) / 500;
  }

  function defaultTouchable() {
    return "ontouchstart" in this;
  }

  function defaultConstrain(transform, extent, translateExtent) {
    var dx0 = transform.invertX(extent[0][0]) - translateExtent[0][0],
        dx1 = transform.invertX(extent[1][0]) - translateExtent[1][0],
        dy0 = transform.invertY(extent[0][1]) - translateExtent[0][1],
        dy1 = transform.invertY(extent[1][1]) - translateExtent[1][1];
    return transform.translate(
      dx1 > dx0 ? (dx0 + dx1) / 2 : Math.min(0, dx0) || Math.max(0, dx1),
      dy1 > dy0 ? (dy0 + dy1) / 2 : Math.min(0, dy0) || Math.max(0, dy1)
    );
  }

  function d3Zoom() {
    var filter = defaultFilter,
        extent = defaultExtent,
        constrain = defaultConstrain,
        wheelDelta = defaultWheelDelta,
        touchable = defaultTouchable,
        scaleExtent = [0, Infinity],
        translateExtent = [[-Infinity, -Infinity], [Infinity, Infinity]],
        duration = 250,
        interpolate = interpolateZoom,
        gestures = [],
        listeners = dispatch("start", "zoom", "end"),
        touchstarting,
        touchending,
        touchDelay = 500,
        wheelDelay = 150,
        clickDistance2 = 0;

    function zoom(selection) {
      selection
          .property("__zoom", defaultTransform)
          .on("wheel.zoom", wheeled)
          .on("mousedown.zoom", mousedowned)
          .on("dblclick.zoom", dblclicked)
        .filter(touchable)
          .on("touchstart.zoom", touchstarted)
          .on("touchmove.zoom", touchmoved)
          .on("touchend.zoom touchcancel.zoom", touchended)
          .style("touch-action", "none")
          .style("-webkit-tap-highlight-color", "rgba(0,0,0,0)");
    }

    zoom.transform = function(collection, transform) {
      var selection = collection.selection ? collection.selection() : collection;
      selection.property("__zoom", defaultTransform);
      if (collection !== selection) {
        schedule(collection, transform);
      } else {
        selection.interrupt().each(function() {
          gesture(this, arguments)
              .start()
              .zoom(null, typeof transform === "function" ? transform.apply(this, arguments) : transform)
              .end();
        });
      }
    };

    zoom.scaleBy = function(selection, k) {
      zoom.scaleTo(selection, function() {
        var k0 = this.__zoom.k,
            k1 = typeof k === "function" ? k.apply(this, arguments) : k;
        return k0 * k1;
      });
    };

    zoom.scaleTo = function(selection, k) {
      zoom.transform(selection, function() {
        var e = extent.apply(this, arguments),
            t0 = this.__zoom,
            p0 = centroid(e),
            p1 = t0.invert(p0),
            k1 = typeof k === "function" ? k.apply(this, arguments) : k;
        return constrain(translate(scale(t0, k1), p0, p1), e, translateExtent);
      });
    };

    zoom.translateBy = function(selection, x, y) {
      zoom.transform(selection, function() {
        return constrain(this.__zoom.translate(
          typeof x === "function" ? x.apply(this, arguments) : x,
          typeof y === "function" ? y.apply(this, arguments) : y
        ), extent.apply(this, arguments), translateExtent);
      });
    };

    zoom.translateTo = function(selection, x, y) {
      zoom.transform(selection, function() {
        var e = extent.apply(this, arguments),
            t = this.__zoom,
            p = centroid(e);
        return constrain(identity$1.translate(p[0], p[1]).scale(t.k).translate(
          typeof x === "function" ? -x.apply(this, arguments) : -x,
          typeof y === "function" ? -y.apply(this, arguments) : -y
        ), e, translateExtent);
      });
    };

    function scale(transform, k) {
      k = Math.max(scaleExtent[0], Math.min(scaleExtent[1], k));
      return k === transform.k ? transform : new Transform(k, transform.x, transform.y);
    }

    function translate(transform, p0, p1) {
      var x = p0[0] - p1[0] * transform.k, y = p0[1] - p1[1] * transform.k;
      return x === transform.x && y === transform.y ? transform : new Transform(transform.k, x, y);
    }

    function centroid(extent) {
      return [(+extent[0][0] + +extent[1][0]) / 2, (+extent[0][1] + +extent[1][1]) / 2];
    }

    function schedule(transition, transform, center) {
      transition
          .on("start.zoom", function() { gesture(this, arguments).start(); })
          .on("interrupt.zoom end.zoom", function() { gesture(this, arguments).end(); })
          .tween("zoom", function() {
            var that = this,
                args = arguments,
                g = gesture(that, args),
                e = extent.apply(that, args),
                p = center || centroid(e),
                w = Math.max(e[1][0] - e[0][0], e[1][1] - e[0][1]),
                a = that.__zoom,
                b = typeof transform === "function" ? transform.apply(that, args) : transform,
                i = interpolate(a.invert(p).concat(w / a.k), b.invert(p).concat(w / b.k));
            return function(t) {
              if (t === 1) t = b; // Avoid rounding error on end.
              else { var l = i(t), k = w / l[2]; t = new Transform(k, p[0] - l[0] * k, p[1] - l[1] * k); }
              g.zoom(null, t);
            };
          });
    }

    function gesture(that, args) {
      for (var i = 0, n = gestures.length, g; i < n; ++i) {
        if ((g = gestures[i]).that === that) {
          return g;
        }
      }
      return new Gesture(that, args);
    }

    function Gesture(that, args) {
      this.that = that;
      this.args = args;
      this.index = -1;
      this.active = 0;
      this.extent = extent.apply(that, args);
    }

    Gesture.prototype = {
      start: function() {
        if (++this.active === 1) {
          this.index = gestures.push(this) - 1;
          this.emit("start");
        }
        return this;
      },
      zoom: function(key, transform) {
        if (this.mouse && key !== "mouse") this.mouse[1] = transform.invert(this.mouse[0]);
        if (this.touch0 && key !== "touch") this.touch0[1] = transform.invert(this.touch0[0]);
        if (this.touch1 && key !== "touch") this.touch1[1] = transform.invert(this.touch1[0]);
        this.that.__zoom = transform;
        this.emit("zoom");
        return this;
      },
      end: function() {
        if (--this.active === 0) {
          gestures.splice(this.index, 1);
          this.index = -1;
          this.emit("end");
        }
        return this;
      },
      emit: function(type) {
        customEvent(new ZoomEvent(zoom, type, this.that.__zoom), listeners.apply, listeners, [type, this.that, this.args]);
      }
    };

    function wheeled() {
      if (!filter.apply(this, arguments)) return;
      var g = gesture(this, arguments),
          t = this.__zoom,
          k = Math.max(scaleExtent[0], Math.min(scaleExtent[1], t.k * Math.pow(2, wheelDelta.apply(this, arguments)))),
          p = mouse(this);

      // If the mouse is in the same location as before, reuse it.
      // If there were recent wheel events, reset the wheel idle timeout.
      if (g.wheel) {
        if (g.mouse[0][0] !== p[0] || g.mouse[0][1] !== p[1]) {
          g.mouse[1] = t.invert(g.mouse[0] = p);
        }
        clearTimeout(g.wheel);
      }

      // If this wheel event won’t trigger a transform change, ignore it.
      else if (t.k === k) return;

      // Otherwise, capture the mouse point and location at the start.
      else {
        g.mouse = [p, t.invert(p)];
        interrupt(this);
        g.start();
      }

      noevent$1();
      g.wheel = setTimeout(wheelidled, wheelDelay);
      g.zoom("mouse", constrain(translate(scale(t, k), g.mouse[0], g.mouse[1]), g.extent, translateExtent));

      function wheelidled() {
        g.wheel = null;
        g.end();
      }
    }

    function mousedowned() {
      if (touchending || !filter.apply(this, arguments)) return;
      var g = gesture(this, arguments),
          v = d3Select(event.view).on("mousemove.zoom", mousemoved, true).on("mouseup.zoom", mouseupped, true),
          p = mouse(this),
          x0 = event.clientX,
          y0 = event.clientY;

      dragDisable(event.view);
      nopropagation();
      g.mouse = [p, this.__zoom.invert(p)];
      interrupt(this);
      g.start();

      function mousemoved() {
        noevent$1();
        if (!g.moved) {
          var dx = event.clientX - x0, dy = event.clientY - y0;
          g.moved = dx * dx + dy * dy > clickDistance2;
        }
        g.zoom("mouse", constrain(translate(g.that.__zoom, g.mouse[0] = mouse(g.that), g.mouse[1]), g.extent, translateExtent));
      }

      function mouseupped() {
        v.on("mousemove.zoom mouseup.zoom", null);
        yesdrag(event.view, g.moved);
        noevent$1();
        g.end();
      }
    }

    function dblclicked() {
      if (!filter.apply(this, arguments)) return;
      var t0 = this.__zoom,
          p0 = mouse(this),
          p1 = t0.invert(p0),
          k1 = t0.k * (event.shiftKey ? 0.5 : 2),
          t1 = constrain(translate(scale(t0, k1), p0, p1), extent.apply(this, arguments), translateExtent);

      noevent$1();
      if (duration > 0) d3Select(this).transition().duration(duration).call(schedule, t1, p0);
      else d3Select(this).call(zoom.transform, t1);
    }

    function touchstarted() {
      if (!filter.apply(this, arguments)) return;
      var g = gesture(this, arguments),
          touches = event.changedTouches,
          started,
          n = touches.length, i, t, p;

      nopropagation();
      for (i = 0; i < n; ++i) {
        t = touches[i], p = touch(this, touches, t.identifier);
        p = [p, this.__zoom.invert(p), t.identifier];
        if (!g.touch0) g.touch0 = p, started = true;
        else if (!g.touch1) g.touch1 = p;
      }

      // If this is a dbltap, reroute to the (optional) dblclick.zoom handler.
      if (touchstarting) {
        touchstarting = clearTimeout(touchstarting);
        if (!g.touch1) {
          g.end();
          p = d3Select(this).on("dblclick.zoom");
          if (p) p.apply(this, arguments);
          return;
        }
      }

      if (started) {
        touchstarting = setTimeout(function() { touchstarting = null; }, touchDelay);
        interrupt(this);
        g.start();
      }
    }

    function touchmoved() {
      var g = gesture(this, arguments),
          touches = event.changedTouches,
          n = touches.length, i, t, p, l;

      noevent$1();
      if (touchstarting) touchstarting = clearTimeout(touchstarting);
      for (i = 0; i < n; ++i) {
        t = touches[i], p = touch(this, touches, t.identifier);
        if (g.touch0 && g.touch0[2] === t.identifier) g.touch0[0] = p;
        else if (g.touch1 && g.touch1[2] === t.identifier) g.touch1[0] = p;
      }
      t = g.that.__zoom;
      if (g.touch1) {
        var p0 = g.touch0[0], l0 = g.touch0[1],
            p1 = g.touch1[0], l1 = g.touch1[1],
            dp = (dp = p1[0] - p0[0]) * dp + (dp = p1[1] - p0[1]) * dp,
            dl = (dl = l1[0] - l0[0]) * dl + (dl = l1[1] - l0[1]) * dl;
        t = scale(t, Math.sqrt(dp / dl));
        p = [(p0[0] + p1[0]) / 2, (p0[1] + p1[1]) / 2];
        l = [(l0[0] + l1[0]) / 2, (l0[1] + l1[1]) / 2];
      }
      else if (g.touch0) p = g.touch0[0], l = g.touch0[1];
      else return;
      g.zoom("touch", constrain(translate(t, p, l), g.extent, translateExtent));
    }

    function touchended() {
      var g = gesture(this, arguments),
          touches = event.changedTouches,
          n = touches.length, i, t;

      nopropagation();
      if (touchending) clearTimeout(touchending);
      touchending = setTimeout(function() { touchending = null; }, touchDelay);
      for (i = 0; i < n; ++i) {
        t = touches[i];
        if (g.touch0 && g.touch0[2] === t.identifier) delete g.touch0;
        else if (g.touch1 && g.touch1[2] === t.identifier) delete g.touch1;
      }
      if (g.touch1 && !g.touch0) g.touch0 = g.touch1, delete g.touch1;
      if (g.touch0) g.touch0[1] = this.__zoom.invert(g.touch0[0]);
      else g.end();
    }

    zoom.wheelDelta = function(_) {
      return arguments.length ? (wheelDelta = typeof _ === "function" ? _ : constant$2(+_), zoom) : wheelDelta;
    };

    zoom.filter = function(_) {
      return arguments.length ? (filter = typeof _ === "function" ? _ : constant$2(!!_), zoom) : filter;
    };

    zoom.touchable = function(_) {
      return arguments.length ? (touchable = typeof _ === "function" ? _ : constant$2(!!_), zoom) : touchable;
    };

    zoom.extent = function(_) {
      return arguments.length ? (extent = typeof _ === "function" ? _ : constant$2([[+_[0][0], +_[0][1]], [+_[1][0], +_[1][1]]]), zoom) : extent;
    };

    zoom.scaleExtent = function(_) {
      return arguments.length ? (scaleExtent[0] = +_[0], scaleExtent[1] = +_[1], zoom) : [scaleExtent[0], scaleExtent[1]];
    };

    zoom.translateExtent = function(_) {
      return arguments.length ? (translateExtent[0][0] = +_[0][0], translateExtent[1][0] = +_[1][0], translateExtent[0][1] = +_[0][1], translateExtent[1][1] = +_[1][1], zoom) : [[translateExtent[0][0], translateExtent[0][1]], [translateExtent[1][0], translateExtent[1][1]]];
    };

    zoom.constrain = function(_) {
      return arguments.length ? (constrain = _, zoom) : constrain;
    };

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

    zoom.interpolate = function(_) {
      return arguments.length ? (interpolate = _, zoom) : interpolate;
    };

    zoom.on = function() {
      var value = listeners.on.apply(listeners, arguments);
      return value === listeners ? zoom : value;
    };

    zoom.clickDistance = function(_) {
      return arguments.length ? (clickDistance2 = (_ = +_) * _, zoom) : Math.sqrt(clickDistance2);
    };

    return zoom;
  }

  /**
   * Returns a function, that, as long as it continues to be invoked, will not
   * be triggered. The function will be called after it stops being called for
   * N milliseconds. If `immediate` is passed, trigger the function on the
   * leading edge, instead of the trailing. The function also has a property 'clear' 
   * that is a function which will clear the timer to prevent previously scheduled executions. 
   *
   * @source underscore.js
   * @see http://unscriptable.com/2009/03/20/debouncing-javascript-methods/
   * @param {Function} function to wrap
   * @param {Number} timeout in ms (`100`)
   * @param {Boolean} whether to execute at the beginning (`false`)
   * @api public
   */
  function debounce(func, wait, immediate){
    var timeout, args, context, timestamp, result;
    if (null == wait) wait = 100;

    function later() {
      var last = Date.now() - timestamp;

      if (last < wait && last >= 0) {
        timeout = setTimeout(later, wait - last);
      } else {
        timeout = null;
        if (!immediate) {
          result = func.apply(context, args);
          context = args = null;
        }
      }
    }
    var debounced = function(){
      context = this;
      args = arguments;
      timestamp = Date.now();
      var callNow = immediate && !timeout;
      if (!timeout) timeout = setTimeout(later, wait);
      if (callNow) {
        result = func.apply(context, args);
        context = args = null;
      }

      return result;
    };

    debounced.clear = function() {
      if (timeout) {
        clearTimeout(timeout);
        timeout = null;
      }
    };
    
    debounced.flush = function() {
      if (timeout) {
        result = func.apply(context, args);
        context = args = null;
        
        clearTimeout(timeout);
        timeout = null;
      }
    };

    return debounced;
  }
  // Adds compatibility for ES modules
  debounce.debounce = debounce;

  var debounce_1 = debounce;

  function _classCallCheck(instance, Constructor) {
    if (!(instance instanceof Constructor)) {
      throw new TypeError("Cannot call a class as a function");
    }
  }

  function _slicedToArray(arr, i) {
    return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _nonIterableRest();
  }

  function _arrayWithHoles(arr) {
    if (Array.isArray(arr)) return arr;
  }

  function _iterableToArrayLimit(arr, i) {
    var _arr = [];
    var _n = true;
    var _d = false;
    var _e = undefined;

    try {
      for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) {
        _arr.push(_s.value);

        if (i && _arr.length === i) break;
      }
    } catch (err) {
      _d = true;
      _e = err;
    } finally {
      try {
        if (!_n && _i["return"] != null) _i["return"]();
      } finally {
        if (_d) throw _e;
      }
    }

    return _arr;
  }

  function _nonIterableRest() {
    throw new TypeError("Invalid attempt to destructure non-iterable instance");
  }

  var Prop = function Prop(name, _ref) {
    var _ref$default = _ref["default"],
        defaultVal = _ref$default === void 0 ? null : _ref$default,
        _ref$triggerUpdate = _ref.triggerUpdate,
        triggerUpdate = _ref$triggerUpdate === void 0 ? true : _ref$triggerUpdate,
        _ref$onChange = _ref.onChange,
        onChange = _ref$onChange === void 0 ? function (newVal, state) {} : _ref$onChange;

    _classCallCheck(this, Prop);

    this.name = name;
    this.defaultVal = defaultVal;
    this.triggerUpdate = triggerUpdate;
    this.onChange = onChange;
  };

  function index (_ref2) {
    var _ref2$stateInit = _ref2.stateInit,
        stateInit = _ref2$stateInit === void 0 ? function () {
      return {};
    } : _ref2$stateInit,
        _ref2$props = _ref2.props,
        rawProps = _ref2$props === void 0 ? {} : _ref2$props,
        _ref2$methods = _ref2.methods,
        methods = _ref2$methods === void 0 ? {} : _ref2$methods,
        _ref2$aliases = _ref2.aliases,
        aliases = _ref2$aliases === void 0 ? {} : _ref2$aliases,
        _ref2$init = _ref2.init,
        initFn = _ref2$init === void 0 ? function () {} : _ref2$init,
        _ref2$update = _ref2.update,
        updateFn = _ref2$update === void 0 ? function () {} : _ref2$update;
    // Parse props into Prop instances
    var props = Object.keys(rawProps).map(function (propName) {
      return new Prop(propName, rawProps[propName]);
    });
    return function () {
      var options = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
      // Holds component state
      var state = Object.assign({}, stateInit instanceof Function ? stateInit(options) : stateInit, // Support plain objects for backwards compatibility
      {
        initialised: false
      }); // Component constructor

      function comp(nodeElement) {
        initStatic(nodeElement, options);
        digest();
        return comp;
      }

      var initStatic = function initStatic(nodeElement, options) {
        initFn.call(comp, nodeElement, state, options);
        state.initialised = true;
      };

      var digest = debounce_1(function () {
        if (!state.initialised) {
          return;
        }

        updateFn.call(comp, state);
      }, 1); // Getter/setter methods

      props.forEach(function (prop) {
        comp[prop.name] = getSetProp(prop.name, prop.triggerUpdate, prop.onChange);

        function getSetProp(prop) {
          var redigest = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
          var onChange = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : function (newVal, state) {};
          return function (_) {
            var curVal = state[prop];

            if (!arguments.length) {
              return curVal;
            } // Getter mode


            state[prop] = _;
            onChange.call(comp, _, state, curVal);

            if (redigest) {
              digest();
            }

            return comp;
          };
        }
      }); // Other methods

      Object.keys(methods).forEach(function (methodName) {
        comp[methodName] = function () {
          var _methods$methodName;

          for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
            args[_key] = arguments[_key];
          }

          return (_methods$methodName = methods[methodName]).call.apply(_methods$methodName, [comp, state].concat(args));
        };
      }); // Link aliases

      Object.entries(aliases).forEach(function (_ref3) {
        var _ref4 = _slicedToArray(_ref3, 2),
            alias = _ref4[0],
            target = _ref4[1];

        return comp[alias] = comp[target];
      }); // Reset all component props to their default value

      comp.resetProps = function () {
        props.forEach(function (prop) {
          comp[prop.name](prop.defaultVal);
        });
        return comp;
      }; //


      comp.resetProps(); // Apply all prop defaults

      state._rerender = digest; // Expose digest method

      return comp;
    };
  }

  var zoomable = index({
    props: {
      htmlEl: {
        onChange: function onChange(el, state) {
          state.htmlEls = (!el ? [] : el instanceof Array ? el : [el]).map(function (el) {
            return _typeof(el) === 'object' && !!el.node && typeof el.node === 'function' ? el // already a D3 selection
            : d3Select(el);
          });
        },
        triggerUpdate: false
      },
      svgEl: {
        onChange: function onChange(el, state) {
          state.svgEls = (!el ? [] : el instanceof Array ? el : [el]).map(function (el) {
            return _typeof(el) === 'object' && !!el.node && typeof el.node === 'function' ? el // already a D3 selection
            : d3Select(el);
          });
        },
        triggerUpdate: false
      },
      canvasEl: {
        onChange: function onChange(el, state) {
          state.canvasCtxs = (!el ? [] : el instanceof Array ? el : [el]).map(function (el) {
            return _typeof(el) === 'object' && !!el.node && typeof el.node === 'function' ? el.node().getContext('2d') // D3 selection
            : el.getContext('2d');
          });
        },
        triggerUpdate: false
      },
      enableX: {
        "default": true,
        triggerUpdate: false
      },
      enableY: {
        "default": true,
        triggerUpdate: false
      },
      scaleExtent: {
        "default": [1, Infinity],
        onChange: function onChange(extent, state) {
          extent && state.zoom.scaleExtent(extent);
        },
        triggerUpdate: false
      },
      translateExtent: {
        onChange: function onChange(extent, state) {
          extent && state.zoom.translateExtent(extent);
        },
        triggerUpdate: false
      },
      onChange: {
        triggerUpdate: false
      }
    },
    methods: {
      current: function current(state) {
        return _objectSpread({}, state.zoomTransform);
      },
      zoomBy: function zoomBy(state, k) {
        var duration = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 0;

        if (state.initialised) {
          state.transitionDuration = duration;
          state.el.call(state.zoom.scaleBy, k);
        }

        return this;
      },
      zoomReset: function zoomReset(state) {
        var duration = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 0;

        if (state.initialised) {
          state.transitionDuration = duration;
          state.el.call(state.zoom.transform, identity$1);
        }

        return this;
      },
      zoomTo: function zoomTo(state, _ref) {
        var _ref$x = _ref.x,
            x = _ref$x === void 0 ? 0 : _ref$x,
            _ref$y = _ref.y,
            y = _ref$y === void 0 ? 0 : _ref$y,
            _ref$k = _ref.k,
            k = _ref$k === void 0 ? 1 : _ref$k;
        var duration = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 0;

        if (state.initialised) {
          state.transitionDuration = duration;
          state.el.call(state.zoom.transform, identity$1.scale(k).translate(x, y));
        }

        return this;
      }
    },
    stateInit: function stateInit() {
      return {
        zoom: d3Zoom().filter(function () {
          return !event.button && !event.dblclick;
        }),
        zoomTransform: {
          x: 0,
          y: 0,
          k: 1
        }
      };
    },
    init: function init(el, state) {
      var isD3Selection = !!el && _typeof(el) === 'object' && !!el.node && typeof el.node === 'function';
      state.el = d3Select(isD3Selection ? el.node() : el);
      state.el.call(state.zoom.on('zoom', function () {
        var tr = _objectSpread({}, event.transform);

        !state.enableX && (tr.x = 0);
        !state.enableY && (tr.y = 0);
        var prevTr = state.zoomTransform;
        state.zoomTransform = tr;
        var duration = state.transitionDuration || 0;
        state.transitionDuration = 0; // reset it

        var scX = state.enableX ? tr.k : 1;
        var scY = state.enableY ? tr.k : 1;
        state.htmlEls.forEach(function (el) {
          (duration ? el.transition().duration(duration) : el).style('transform', "translate(".concat(tr.x, "px, ").concat(tr.y, "px) scale(").concat(scX, ", ").concat(scY, ")"));
        });
        state.svgEls.forEach(function (el) {
          (duration ? el.transition().duration(duration) : el).attr('transform', "translate(".concat(tr.x, ", ").concat(tr.y, ") scale(").concat(scX, ", ").concat(scY, ")"));
        });
        state.canvasCtxs.forEach(function (ctx, idx) {
          var applyTr = function applyTr(_ref2) {
            var x = _ref2.x,
                y = _ref2.y,
                scX = _ref2.scX,
                scY = _ref2.scY;
            ctx.setTransform(scX, 0, 0, scY, x, y);
          };

          duration ? transition().duration(duration).tween("animate-ctx-".concat(idx), function () {
            var xIpol = d3InterpolateNumber(prevTr.x, tr.x);
            var yIpol = d3InterpolateNumber(prevTr.y, tr.y);
            var scXIpol = state.enableX ? d3InterpolateNumber(prevTr.k, tr.k) : function () {
              return 1;
            };
            var scYIpol = state.enableY ? d3InterpolateNumber(prevTr.k, tr.k) : function () {
              return 1;
            };
            return function (t) {
              return applyTr({
                x: xIpol(t),
                y: yIpol(t),
                scX: scXIpol(t),
                scY: scYIpol(t)
              });
            };
          }) : applyTr(_objectSpread({
            scX: scX,
            scY: scY
          }, tr));
        });
        state.onChange && state.onChange(tr, prevTr, duration);
      }));
      state.el.on('dblclick.zoom', null); // Disable double-click zoom
    }
  });

  return zoomable;

}));
//# sourceMappingURL=d3-zoomable.js.map