ngraph.louvain/demo/basic/bundle.js

Given a graph instance detects communities using the Louvain Method

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

var getColor = require('../lib/getColor.js');
var graph = require('../lib/getGraph.js');

console.time('cluster');
var clusters = modularity(graph);
console.timeEnd('cluster');

// We use svg renderer, but this could be any renderer
renderGraph(graph);

function renderGraph(graph) {
  var render = require('ngraph.svg');
  var svg = render.svg;

  var renderer = render(graph, {
    physics: {
      springLength : 55,
      springCoeff : 0.00055,
      dragCoeff : 0.09,
      gravity : -1
    }
  });

  renderer.node(createNode).placeNode(renderNode);

  renderer.run();

  function renderNode(ui, pos, node) {
    var currentClass = clusters.getClass(node.id);
    if (ui.label !== currentClass) {
      ui.label = currentClass;
      ui.labelEl.text(currentClass);
      ui.circleEl.attr('fill', getColor(currentClass));
    }
    ui.attr('transform', 'translate(' + (pos.x ) + ',' + (pos.y) + ')');
  }

  function createNode() {
    var ui = svg('g');
        // Create SVG text element with user id as content
    var label = svg('text').attr('y', '-8px');
    var circle = svg('circle', {
      r: 7,
      stroke: '#fff',
      fill: '#ff00ef',
      'stroke-width': '1.5px'
    });
    ui.append(label);
    ui.append(circle);

    // yeah, ugly. Storing label dom element, so that we can update labels later
    ui.labelEl = label;
    ui.circleEl = circle;
    return ui;
  }
}

},{"../../":4,"../lib/getColor.js":2,"../lib/getGraph.js":3,"ngraph.svg":29}],2:[function(require,module,exports){
var colors = [
  '#1f77b4', '#aec7e8',
  '#ff7f0e', '#ffbb78',
  '#2ca02c', '#98df8a',
  '#d62728', '#ff9896',
  '#9467bd', '#c5b0d5',
  '#8c564b', '#c49c94',
  '#e377c2', '#f7b6d2',
  '#7f7f7f', '#c7c7c7',
  '#bcbd22'
];

var lastUsed = 0;
var idToIndex = Object.create(null);

function getColor(id) {
  var idx = idToIndex[id];
  if (idx === undefined) {
    idx = idToIndex[id] = lastUsed;
    lastUsed += 1;
  }
  return colors[idx];
}

module.exports = getColor;

},{}],3:[function(require,module,exports){
var graph = require('miserables')


// by default miserables comes with weights. For the pupose of this demo we will
// remove all weights from the graph:
graph.forEachLink(function(link) {
  link.data = 1;
});

module.exports = graph;

},{"miserables":10}],4:[function(require,module,exports){
var createCommunityGraph = require('./lib/createCommunityGraph.js');
var createCommunity = require('./lib/createCommunity.js');

module.exports = modularity;

function modularity(ngraph, options) {
  var graph = createCommunityGraph(ngraph);
  var community = createCommunity(graph, options);
  var originalModularity = community.modularity();

  var modularityImproved = community.optimizeModularity();
  var newModularity = community.modularity();

  return {
    canCoarse: canCoarse,
    originalModularity: originalModularity,
    newModularity: newModularity,
    getClass: getClass
  };

  function canCoarse() {
    // If there was movement last turn - we can coarse graph further.
    return modularityImproved;
  }

  function getClass(nodeId) {
    var node = graph.getNodeIdFromNgraph(nodeId);
    return community.getClass(node);
  }
}



},{"./lib/createCommunity.js":5,"./lib/createCommunityGraph.js":6}],5:[function(require,module,exports){
var nrandom = require('ngraph.random');
var randomIterator = nrandom.randomIterator;

module.exports = createCommunity;

function createCommunity(graph, options) {
  var graphWeight = graph.weight;
  var nodeCount = graph.nodeCount;
  var seededRandom = nrandom.random(42);

  var totalLinksWeight = new Float32Array(nodeCount);
  var internalLinksWeight = new Float32Array(nodeCount);
  var nodeToCommunity = new Uint32Array(nodeCount);

  for (var i = 0; i < nodeCount; ++i) {
    // each node belongs to it's own community at the start
    nodeToCommunity[i] = i;
    totalLinksWeight[i] = graph.getWeightedDegree(i);
    internalLinksWeight[i] = graph.getSelfLoopsCount(i);
  }

  return {
    /**
     * compute modularity of the current community
     */
    modularity: modularity,

    /**
     * Attempts to optimize communities of the graph. Returns true if any nodes
     * were moved; False otherwise.
     */
    optimizeModularity: optimizeModularity,

    /**
     * Given a node id returns its "class" (a cluster id);
     */
    getClass: getClass
  }

  function getClass(id) {
    return nodeToCommunity[id];
  }

  function optimizeModularity() {
    var epsilon = 0.000001;
    if (options && (options.seed !== undefined)) {
      seededRandom = nrandom.random(options.seed);
    }

    var iterator = getRandomNodeIdIterator();
    var newModularity = modularity();
    var currentModularity, movesCount;
    var modularityImproved = false;

    do {
      movesCount = 0;
      currentModularity = newModularity;
      for (var i = 0; i < iterator.length; ++i) {
        var node = iterator[i];
        var nodeCommunity = nodeToCommunity[node];

        var neigboughingCommunities = getNeighbouringCommunities(node);

        var sharedLinksWeight = neigboughingCommunities.get(nodeCommunity);
        removeFromCommunity(node, nodeCommunity, sharedLinksWeight);

        var weightedDegree = graph.getWeightedDegree(node);
        var bestCommunity = nodeCommunity;
        var bestGain = 0;

        neigboughingCommunities.forEach(function(sharedWeight, communityId) {
          var gain = getModularityGain(sharedWeight, communityId, weightedDegree);
          if (gain <= bestGain) return;

          bestCommunity = communityId;
          bestGain = gain;
        });

        var bestSharedWeight = neigboughingCommunities.get(bestCommunity);
        insertIntoCommunity(node, bestCommunity, bestSharedWeight);

        if (bestCommunity !== nodeCommunity) movesCount += 1;
      }

      newModularity = modularity();
      if (movesCount > 0) modularityImproved = true;
    } while (movesCount > 0 && newModularity - currentModularity > epsilon);

    return modularityImproved;
  }

  function getNeighbouringCommunities(nodeId) {
    // map from community id to total links weight between this node and that community
    var map = new Map();
    map.set(nodeToCommunity[nodeId], 0);

    graph.forEachNeigbour(nodeId, function(otherNodeId, edgeWeight) {
      var otherCommunity = nodeToCommunity[otherNodeId];
      var currentValue = map.get(otherCommunity) || 0;
      map.set(otherCommunity, currentValue + edgeWeight);
    });

    return map;
  }

  function getModularityGain(sharedWeight, communityId, degree) {
    var totalLinksWeightInThisCommunity = totalLinksWeight[communityId];

    return sharedWeight - totalLinksWeightInThisCommunity * degree/graphWeight;
  }

  function removeFromCommunity(nodeId, communityId, sharedLinksWeight) {
    totalLinksWeight[communityId] -= graph.getWeightedDegree(nodeId);
    internalLinksWeight[communityId] -= 2 * sharedLinksWeight + graph.getSelfLoopsCount(nodeId);
    nodeToCommunity[nodeId] = -1;
  }

  function insertIntoCommunity(nodeId, communityId, sharedLinksWeight) {
    totalLinksWeight[communityId] += graph.getWeightedDegree(nodeId);
    internalLinksWeight[communityId] += 2 * sharedLinksWeight + graph.getSelfLoopsCount(nodeId);
    nodeToCommunity[nodeId] = communityId;
  }

  function modularity() {
    var result = 0;

    for (var communityId = 0; communityId < nodeCount; ++communityId) {
      if (totalLinksWeight[communityId] > 0) {
        var dw = totalLinksWeight[communityId] / graphWeight;
        result += internalLinksWeight[communityId] / graphWeight - dw * dw;
      }
    }

    return result;
  }

  function getRandomNodeIdIterator() {
      var iterator = [];

      for (var i = 0; i < nodeCount; ++i) {
        iterator[i] = i;
      }

      randomIterator(iterator, seededRandom).shuffle();

      return iterator;
  }
}

},{"ngraph.random":28}],6:[function(require,module,exports){
module.exports = createCommunityGraph;

function createCommunityGraph(ngraph) {
  var nodeCount = ngraph.getNodesCount();
  var weight = 0;
  var nodes = [];
  var indexLookup = new Map();

  ngraph.forEachNode(function(node) {
    initNode(node.id);
  });

  ngraph.forEachLink(function(link) {
    var fromIdx = getNodeIdFromNgraph(link.fromId);
    var toIdx = getNodeIdFromNgraph(link.toId);

    var weight = getWeight(link.data);
    var fromNode = nodes[fromIdx];
    var toNode = nodes[toIdx];

    if (fromIdx === toIdx) {
      fromNode.selfLoopsCount += weight;
      fromNode.weightedDegree += weight;
    } else {
      // We do not list self-loops here.
      addNeighbour(fromNode, toIdx, weight);
      addNeighbour(toNode, fromIdx, weight);
      fromNode.weightedDegree += weight;
      toNode.weightedDegree += weight;
    }
  });

  weight = computeTotalWeight();

  return {
    nodeCount: nodeCount,
    weight: weight,

    forEachNeigbour: forEachNeigbour,

    getWeightedDegree: getWeightedDegree,
    getSelfLoopsCount: getSelfLoopsCount,

    getNodeIdFromNgraph: getNodeIdFromNgraph
  };

  function getNodeIdFromNgraph(id) {
    var idx = indexLookup.get(id);
    if (idx === undefined) throw new Error('Unknown node id: ' + id);

    return idx;
  }

  function addNeighbour(node, id, weight) {
      var info = {
        id: id,
        weight: weight
      };
      if (!node.neighbours) node.neighbours = [info];
      else node.neighbours.push(info);
      // PS: We do not init neighbours array unless it's truly needed
  }

  function forEachNeigbour(nodeId, cb) {
    var node = getNode(nodeId);
    if (!node.neighbours) return;

    for (var i = 0; i < node.neighbours.length; ++i) {
      var info = node.neighbours[i];
      cb(info.id, info.weight);
    }
  }

  function computeTotalWeight() {
    var weight = 0;
    for (var i = 0; i < nodeCount; ++i) {
      weight += getWeightedDegree(i);
    }
    return weight;
  }

  function getSelfLoopsCount(nodeId) {
    return getNode(nodeId).selfLoopsCount;
  }

  function getWeightedDegree(nodeId) {
    return getNode(nodeId).weightedDegree;
  }

  function getNode(nodeId) {
    var node = nodes[nodeId];
    if (!node) throw new Error('cannot find node with id: ' + nodeId);

    return node;
  }

  function initNode(id) {
    var node = {
      selfLoopsCount: 0,
      weightedDegree: 0,
      neighbours: null
    };

    var idx = nodes.length;
    indexLookup.set(id, idx);
    nodes.push(node);

    return idx;
  }
}

function getWeight(data) {
  if (!data) return 1;

  if (typeof data === 'number') return data;
  if (typeof data.weight === 'number') return data.weight;

  return 1;
}

},{}],7:[function(require,module,exports){
addEventListener.removeEventListener = removeEventListener
addEventListener.addEventListener = addEventListener

module.exports = addEventListener

var Events = null

function addEventListener(el, eventName, listener, useCapture) {
  Events = Events || (
    document.addEventListener ?
    {add: stdAttach, rm: stdDetach} :
    {add: oldIEAttach, rm: oldIEDetach}
  )
  
  return Events.add(el, eventName, listener, useCapture)
}

function removeEventListener(el, eventName, listener, useCapture) {
  Events = Events || (
    document.addEventListener ?
    {add: stdAttach, rm: stdDetach} :
    {add: oldIEAttach, rm: oldIEDetach}
  )
  
  return Events.rm(el, eventName, listener, useCapture)
}

function stdAttach(el, eventName, listener, useCapture) {
  el.addEventListener(eventName, listener, useCapture)
}

function stdDetach(el, eventName, listener, useCapture) {
  el.removeEventListener(eventName, listener, useCapture)
}

function oldIEAttach(el, eventName, listener, useCapture) {
  if(useCapture) {
    throw new Error('cannot useCapture in oldIE')
  }

  el.attachEvent('on' + eventName, listener)
}

function oldIEDetach(el, eventName, listener, useCapture) {
  el.detachEvent('on' + eventName, listener)
}

},{}],8:[function(require,module,exports){
/*! Hammer.JS - v2.0.7 - 2016-04-22
 * http://hammerjs.github.io/
 *
 * Copyright (c) 2016 Jorik Tangelder;
 * Licensed under the MIT license */
(function(window, document, exportName, undefined) {
  'use strict';

var VENDOR_PREFIXES = ['', 'webkit', 'Moz', 'MS', 'ms', 'o'];
var TEST_ELEMENT = document.createElement('div');

var TYPE_FUNCTION = 'function';

var round = Math.round;
var abs = Math.abs;
var now = Date.now;

/**
 * set a timeout with a given scope
 * @param {Function} fn
 * @param {Number} timeout
 * @param {Object} context
 * @returns {number}
 */
function setTimeoutContext(fn, timeout, context) {
    return setTimeout(bindFn(fn, context), timeout);
}

/**
 * if the argument is an array, we want to execute the fn on each entry
 * if it aint an array we don't want to do a thing.
 * this is used by all the methods that accept a single and array argument.
 * @param {*|Array} arg
 * @param {String} fn
 * @param {Object} [context]
 * @returns {Boolean}
 */
function invokeArrayArg(arg, fn, context) {
    if (Array.isArray(arg)) {
        each(arg, context[fn], context);
        return true;
    }
    return false;
}

/**
 * walk objects and arrays
 * @param {Object} obj
 * @param {Function} iterator
 * @param {Object} context
 */
function each(obj, iterator, context) {
    var i;

    if (!obj) {
        return;
    }

    if (obj.forEach) {
        obj.forEach(iterator, context);
    } else if (obj.length !== undefined) {
        i = 0;
        while (i < obj.length) {
            iterator.call(context, obj[i], i, obj);
            i++;
        }
    } else {
        for (i in obj) {
            obj.hasOwnProperty(i) && iterator.call(context, obj[i], i, obj);
        }
    }
}

/**
 * wrap a method with a deprecation warning and stack trace
 * @param {Function} method
 * @param {String} name
 * @param {String} message
 * @returns {Function} A new function wrapping the supplied method.
 */
function deprecate(method, name, message) {
    var deprecationMessage = 'DEPRECATED METHOD: ' + name + '\n' + message + ' AT \n';
    return function() {
        var e = new Error('get-stack-trace');
        var stack = e && e.stack ? e.stack.replace(/^[^\(]+?[\n$]/gm, '')
            .replace(/^\s+at\s+/gm, '')
            .replace(/^Object.<anonymous>\s*\(/gm, '{anonymous}()@') : 'Unknown Stack Trace';

        var log = window.console && (window.console.warn || window.console.log);
        if (log) {
            log.call(window.console, deprecationMessage, stack);
        }
        return method.apply(this, arguments);
    };
}

/**
 * extend object.
 * means that properties in dest will be overwritten by the ones in src.
 * @param {Object} target
 * @param {...Object} objects_to_assign
 * @returns {Object} target
 */
var assign;
if (typeof Object.assign !== 'function') {
    assign = function assign(target) {
        if (target === undefined || target === null) {
            throw new TypeError('Cannot convert undefined or null to object');
        }

        var output = Object(target);
        for (var index = 1; index < arguments.length; index++) {
            var source = arguments[index];
            if (source !== undefined && source !== null) {
                for (var nextKey in source) {
                    if (source.hasOwnProperty(nextKey)) {
                        output[nextKey] = source[nextKey];
                    }
                }
            }
        }
        return output;
    };
} else {
    assign = Object.assign;
}

/**
 * extend object.
 * means that properties in dest will be overwritten by the ones in src.
 * @param {Object} dest
 * @param {Object} src
 * @param {Boolean} [merge=false]
 * @returns {Object} dest
 */
var extend = deprecate(function extend(dest, src, merge) {
    var keys = Object.keys(src);
    var i = 0;
    while (i < keys.length) {
        if (!merge || (merge && dest[keys[i]] === undefined)) {
            dest[keys[i]] = src[keys[i]];
        }
        i++;
    }
    return dest;
}, 'extend', 'Use `assign`.');

/**
 * merge the values from src in the dest.
 * means that properties that exist in dest will not be overwritten by src
 * @param {Object} dest
 * @param {Object} src
 * @returns {Object} dest
 */
var merge = deprecate(function merge(dest, src) {
    return extend(dest, src, true);
}, 'merge', 'Use `assign`.');

/**
 * simple class inheritance
 * @param {Function} child
 * @param {Function} base
 * @param {Object} [properties]
 */
function inherit(child, base, properties) {
    var baseP = base.prototype,
        childP;

    childP = child.prototype = Object.create(baseP);
    childP.constructor = child;
    childP._super = baseP;

    if (properties) {
        assign(childP, properties);
    }
}

/**
 * simple function bind
 * @param {Function} fn
 * @param {Object} context
 * @returns {Function}
 */
function bindFn(fn, context) {
    return function boundFn() {
        return fn.apply(context, arguments);
    };
}

/**
 * let a boolean value also be a function that must return a boolean
 * this first item in args will be used as the context
 * @param {Boolean|Function} val
 * @param {Array} [args]
 * @returns {Boolean}
 */
function boolOrFn(val, args) {
    if (typeof val == TYPE_FUNCTION) {
        return val.apply(args ? args[0] || undefined : undefined, args);
    }
    return val;
}

/**
 * use the val2 when val1 is undefined
 * @param {*} val1
 * @param {*} val2
 * @returns {*}
 */
function ifUndefined(val1, val2) {
    return (val1 === undefined) ? val2 : val1;
}

/**
 * addEventListener with multiple events at once
 * @param {EventTarget} target
 * @param {String} types
 * @param {Function} handler
 */
function addEventListeners(target, types, handler) {
    each(splitStr(types), function(type) {
        target.addEventListener(type, handler, false);
    });
}

/**
 * removeEventListener with multiple events at once
 * @param {EventTarget} target
 * @param {String} types
 * @param {Function} handler
 */
function removeEventListeners(target, types, handler) {
    each(splitStr(types), function(type) {
        target.removeEventListener(type, handler, false);
    });
}

/**
 * find if a node is in the given parent
 * @method hasParent
 * @param {HTMLElement} node
 * @param {HTMLElement} parent
 * @return {Boolean} found
 */
function hasParent(node, parent) {
    while (node) {
        if (node == parent) {
            return true;
        }
        node = node.parentNode;
    }
    return false;
}

/**
 * small indexOf wrapper
 * @param {String} str
 * @param {String} find
 * @returns {Boolean} found
 */
function inStr(str, find) {
    return str.indexOf(find) > -1;
}

/**
 * split string on whitespace
 * @param {String} str
 * @returns {Array} words
 */
function splitStr(str) {
    return str.trim().split(/\s+/g);
}

/**
 * find if a array contains the object using indexOf or a simple polyFill
 * @param {Array} src
 * @param {String} find
 * @param {String} [findByKey]
 * @return {Boolean|Number} false when not found, or the index
 */
function inArray(src, find, findByKey) {
    if (src.indexOf && !findByKey) {
        return src.indexOf(find);
    } else {
        var i = 0;
        while (i < src.length) {
            if ((findByKey && src[i][findByKey] == find) || (!findByKey && src[i] === find)) {
                return i;
            }
            i++;
        }
        return -1;
    }
}

/**
 * convert array-like objects to real arrays
 * @param {Object} obj
 * @returns {Array}
 */
function toArray(obj) {
    return Array.prototype.slice.call(obj, 0);
}

/**
 * unique array with objects based on a key (like 'id') or just by the array's value
 * @param {Array} src [{id:1},{id:2},{id:1}]
 * @param {String} [key]
 * @param {Boolean} [sort=False]
 * @returns {Array} [{id:1},{id:2}]
 */
function uniqueArray(src, key, sort) {
    var results = [];
    var values = [];
    var i = 0;

    while (i < src.length) {
        var val = key ? src[i][key] : src[i];
        if (inArray(values, val) < 0) {
            results.push(src[i]);
        }
        values[i] = val;
        i++;
    }

    if (sort) {
        if (!key) {
            results = results.sort();
        } else {
            results = results.sort(function sortUniqueArray(a, b) {
                return a[key] > b[key];
            });
        }
    }

    return results;
}

/**
 * get the prefixed property
 * @param {Object} obj
 * @param {String} property
 * @returns {String|Undefined} prefixed
 */
function prefixed(obj, property) {
    var prefix, prop;
    var camelProp = property[0].toUpperCase() + property.slice(1);

    var i = 0;
    while (i < VENDOR_PREFIXES.length) {
        prefix = VENDOR_PREFIXES[i];
        prop = (prefix) ? prefix + camelProp : property;

        if (prop in obj) {
            return prop;
        }
        i++;
    }
    return undefined;
}

/**
 * get a unique id
 * @returns {number} uniqueId
 */
var _uniqueId = 1;
function uniqueId() {
    return _uniqueId++;
}

/**
 * get the window object of an element
 * @param {HTMLElement} element
 * @returns {DocumentView|Window}
 */
function getWindowForElement(element) {
    var doc = element.ownerDocument || element;
    return (doc.defaultView || doc.parentWindow || window);
}

var MOBILE_REGEX = /mobile|tablet|ip(ad|hone|od)|android/i;

var SUPPORT_TOUCH = ('ontouchstart' in window);
var SUPPORT_POINTER_EVENTS = prefixed(window, 'PointerEvent') !== undefined;
var SUPPORT_ONLY_TOUCH = SUPPORT_TOUCH && MOBILE_REGEX.test(navigator.userAgent);

var INPUT_TYPE_TOUCH = 'touch';
var INPUT_TYPE_PEN = 'pen';
var INPUT_TYPE_MOUSE = 'mouse';
var INPUT_TYPE_KINECT = 'kinect';

var COMPUTE_INTERVAL = 25;

var INPUT_START = 1;
var INPUT_MOVE = 2;
var INPUT_END = 4;
var INPUT_CANCEL = 8;

var DIRECTION_NONE = 1;
var DIRECTION_LEFT = 2;
var DIRECTION_RIGHT = 4;
var DIRECTION_UP = 8;
var DIRECTION_DOWN = 16;

var DIRECTION_HORIZONTAL = DIRECTION_LEFT | DIRECTION_RIGHT;
var DIRECTION_VERTICAL = DIRECTION_UP | DIRECTION_DOWN;
var DIRECTION_ALL = DIRECTION_HORIZONTAL | DIRECTION_VERTICAL;

var PROPS_XY = ['x', 'y'];
var PROPS_CLIENT_XY = ['clientX', 'clientY'];

/**
 * create new input type manager
 * @param {Manager} manager
 * @param {Function} callback
 * @returns {Input}
 * @constructor
 */
function Input(manager, callback) {
    var self = this;
    this.manager = manager;
    this.callback = callback;
    this.element = manager.element;
    this.target = manager.options.inputTarget;

    // smaller wrapper around the handler, for the scope and the enabled state of the manager,
    // so when disabled the input events are completely bypassed.
    this.domHandler = function(ev) {
        if (boolOrFn(manager.options.enable, [manager])) {
            self.handler(ev);
        }
    };

    this.init();

}

Input.prototype = {
    /**
     * should handle the inputEvent data and trigger the callback
     * @virtual
     */
    handler: function() { },

    /**
     * bind the events
     */
    init: function() {
        this.evEl && addEventListeners(this.element, this.evEl, this.domHandler);
        this.evTarget && addEventListeners(this.target, this.evTarget, this.domHandler);
        this.evWin && addEventListeners(getWindowForElement(this.element), this.evWin, this.domHandler);
    },

    /**
     * unbind the events
     */
    destroy: function() {
        this.evEl && removeEventListeners(this.element, this.evEl, this.domHandler);
        this.evTarget && removeEventListeners(this.target, this.evTarget, this.domHandler);
        this.evWin && removeEventListeners(getWindowForElement(this.element), this.evWin, this.domHandler);
    }
};

/**
 * create new input type manager
 * called by the Manager constructor
 * @param {Hammer} manager
 * @returns {Input}
 */
function createInputInstance(manager) {
    var Type;
    var inputClass = manager.options.inputClass;

    if (inputClass) {
        Type = inputClass;
    } else if (SUPPORT_POINTER_EVENTS) {
        Type = PointerEventInput;
    } else if (SUPPORT_ONLY_TOUCH) {
        Type = TouchInput;
    } else if (!SUPPORT_TOUCH) {
        Type = MouseInput;
    } else {
        Type = TouchMouseInput;
    }
    return new (Type)(manager, inputHandler);
}

/**
 * handle input events
 * @param {Manager} manager
 * @param {String} eventType
 * @param {Object} input
 */
function inputHandler(manager, eventType, input) {
    var pointersLen = input.pointers.length;
    var changedPointersLen = input.changedPointers.length;
    var isFirst = (eventType & INPUT_START && (pointersLen - changedPointersLen === 0));
    var isFinal = (eventType & (INPUT_END | INPUT_CANCEL) && (pointersLen - changedPointersLen === 0));

    input.isFirst = !!isFirst;
    input.isFinal = !!isFinal;

    if (isFirst) {
        manager.session = {};
    }

    // source event is the normalized value of the domEvents
    // like 'touchstart, mouseup, pointerdown'
    input.eventType = eventType;

    // compute scale, rotation etc
    computeInputData(manager, input);

    // emit secret event
    manager.emit('hammer.input', input);

    manager.recognize(input);
    manager.session.prevInput = input;
}

/**
 * extend the data with some usable properties like scale, rotate, velocity etc
 * @param {Object} manager
 * @param {Object} input
 */
function computeInputData(manager, input) {
    var session = manager.session;
    var pointers = input.pointers;
    var pointersLength = pointers.length;

    // store the first input to calculate the distance and direction
    if (!session.firstInput) {
        session.firstInput = simpleCloneInputData(input);
    }

    // to compute scale and rotation we need to store the multiple touches
    if (pointersLength > 1 && !session.firstMultiple) {
        session.firstMultiple = simpleCloneInputData(input);
    } else if (pointersLength === 1) {
        session.firstMultiple = false;
    }

    var firstInput = session.firstInput;
    var firstMultiple = session.firstMultiple;
    var offsetCenter = firstMultiple ? firstMultiple.center : firstInput.center;

    var center = input.center = getCenter(pointers);
    input.timeStamp = now();
    input.deltaTime = input.timeStamp - firstInput.timeStamp;

    input.angle = getAngle(offsetCenter, center);
    input.distance = getDistance(offsetCenter, center);

    computeDeltaXY(session, input);
    input.offsetDirection = getDirection(input.deltaX, input.deltaY);

    var overallVelocity = getVelocity(input.deltaTime, input.deltaX, input.deltaY);
    input.overallVelocityX = overallVelocity.x;
    input.overallVelocityY = overallVelocity.y;
    input.overallVelocity = (abs(overallVelocity.x) > abs(overallVelocity.y)) ? overallVelocity.x : overallVelocity.y;

    input.scale = firstMultiple ? getScale(firstMultiple.pointers, pointers) : 1;
    input.rotation = firstMultiple ? getRotation(firstMultiple.pointers, pointers) : 0;

    input.maxPointers = !session.prevInput ? input.pointers.length : ((input.pointers.length >
        session.prevInput.maxPointers) ? input.pointers.length : session.prevInput.maxPointers);

    computeIntervalInputData(session, input);

    // find the correct target
    var target = manager.element;
    if (hasParent(input.srcEvent.target, target)) {
        target = input.srcEvent.target;
    }
    input.target = target;
}

function computeDeltaXY(session, input) {
    var center = input.center;
    var offset = session.offsetDelta || {};
    var prevDelta = session.prevDelta || {};
    var prevInput = session.prevInput || {};

    if (input.eventType === INPUT_START || prevInput.eventType === INPUT_END) {
        prevDelta = session.prevDelta = {
            x: prevInput.deltaX || 0,
            y: prevInput.deltaY || 0
        };

        offset = session.offsetDelta = {
            x: center.x,
            y: center.y
        };
    }

    input.deltaX = prevDelta.x + (center.x - offset.x);
    input.deltaY = prevDelta.y + (center.y - offset.y);
}

/**
 * velocity is calculated every x ms
 * @param {Object} session
 * @param {Object} input
 */
function computeIntervalInputData(session, input) {
    var last = session.lastInterval || input,
        deltaTime = input.timeStamp - last.timeStamp,
        velocity, velocityX, velocityY, direction;

    if (input.eventType != INPUT_CANCEL && (deltaTime > COMPUTE_INTERVAL || last.velocity === undefined)) {
        var deltaX = input.deltaX - last.deltaX;
        var deltaY = input.deltaY - last.deltaY;

        var v = getVelocity(deltaTime, deltaX, deltaY);
        velocityX = v.x;
        velocityY = v.y;
        velocity = (abs(v.x) > abs(v.y)) ? v.x : v.y;
        direction = getDirection(deltaX, deltaY);

        session.lastInterval = input;
    } else {
        // use latest velocity info if it doesn't overtake a minimum period
        velocity = last.velocity;
        velocityX = last.velocityX;
        velocityY = last.velocityY;
        direction = last.direction;
    }

    input.velocity = velocity;
    input.velocityX = velocityX;
    input.velocityY = velocityY;
    input.direction = direction;
}

/**
 * create a simple clone from the input used for storage of firstInput and firstMultiple
 * @param {Object} input
 * @returns {Object} clonedInputData
 */
function simpleCloneInputData(input) {
    // make a simple copy of the pointers because we will get a reference if we don't
    // we only need clientXY for the calculations
    var pointers = [];
    var i = 0;
    while (i < input.pointers.length) {
        pointers[i] = {
            clientX: round(input.pointers[i].clientX),
            clientY: round(input.pointers[i].clientY)
        };
        i++;
    }

    return {
        timeStamp: now(),
        pointers: pointers,
        center: getCenter(pointers),
        deltaX: input.deltaX,
        deltaY: input.deltaY
    };
}

/**
 * get the center of all the pointers
 * @param {Array} pointers
 * @return {Object} center contains `x` and `y` properties
 */
function getCenter(pointers) {
    var pointersLength = pointers.length;

    // no need to loop when only one touch
    if (pointersLength === 1) {
        return {
            x: round(pointers[0].clientX),
            y: round(pointers[0].clientY)
        };
    }

    var x = 0, y = 0, i = 0;
    while (i < pointersLength) {
        x += pointers[i].clientX;
        y += pointers[i].clientY;
        i++;
    }

    return {
        x: round(x / pointersLength),
        y: round(y / pointersLength)
    };
}

/**
 * calculate the velocity between two points. unit is in px per ms.
 * @param {Number} deltaTime
 * @param {Number} x
 * @param {Number} y
 * @return {Object} velocity `x` and `y`
 */
function getVelocity(deltaTime, x, y) {
    return {
        x: x / deltaTime || 0,
        y: y / deltaTime || 0
    };
}

/**
 * get the direction between two points
 * @param {Number} x
 * @param {Number} y
 * @return {Number} direction
 */
function getDirection(x, y) {
    if (x === y) {
        return DIRECTION_NONE;
    }

    if (abs(x) >= abs(y)) {
        return x < 0 ? DIRECTION_LEFT : DIRECTION_RIGHT;
    }
    return y < 0 ? DIRECTION_UP : DIRECTION_DOWN;
}

/**
 * calculate the absolute distance between two points
 * @param {Object} p1 {x, y}
 * @param {Object} p2 {x, y}
 * @param {Array} [props] containing x and y keys
 * @return {Number} distance
 */
function getDistance(p1, p2, props) {
    if (!props) {
        props = PROPS_XY;
    }
    var x = p2[props[0]] - p1[props[0]],
        y = p2[props[1]] - p1[props[1]];

    return Math.sqrt((x * x) + (y * y));
}

/**
 * calculate the angle between two coordinates
 * @param {Object} p1
 * @param {Object} p2
 * @param {Array} [props] containing x and y keys
 * @return {Number} angle
 */
function getAngle(p1, p2, props) {
    if (!props) {
        props = PROPS_XY;
    }
    var x = p2[props[0]] - p1[props[0]],
        y = p2[props[1]] - p1[props[1]];
    return Math.atan2(y, x) * 180 / Math.PI;
}

/**
 * calculate the rotation degrees between two pointersets
 * @param {Array} start array of pointers
 * @param {Array} end array of pointers
 * @return {Number} rotation
 */
function getRotation(start, end) {
    return getAngle(end[1], end[0], PROPS_CLIENT_XY) + getAngle(start[1], start[0], PROPS_CLIENT_XY);
}

/**
 * calculate the scale factor between two pointersets
 * no scale is 1, and goes down to 0 when pinched together, and bigger when pinched out
 * @param {Array} start array of pointers
 * @param {Array} end array of pointers
 * @return {Number} scale
 */
function getScale(start, end) {
    return getDistance(end[0], end[1], PROPS_CLIENT_XY) / getDistance(start[0], start[1], PROPS_CLIENT_XY);
}

var MOUSE_INPUT_MAP = {
    mousedown: INPUT_START,
    mousemove: INPUT_MOVE,
    mouseup: INPUT_END
};

var MOUSE_ELEMENT_EVENTS = 'mousedown';
var MOUSE_WINDOW_EVENTS = 'mousemove mouseup';

/**
 * Mouse events input
 * @constructor
 * @extends Input
 */
function MouseInput() {
    this.evEl = MOUSE_ELEMENT_EVENTS;
    this.evWin = MOUSE_WINDOW_EVENTS;

    this.pressed = false; // mousedown state

    Input.apply(this, arguments);
}

inherit(MouseInput, Input, {
    /**
     * handle mouse events
     * @param {Object} ev
     */
    handler: function MEhandler(ev) {
        var eventType = MOUSE_INPUT_MAP[ev.type];

        // on start we want to have the left mouse button down
        if (eventType & INPUT_START && ev.button === 0) {
            this.pressed = true;
        }

        if (eventType & INPUT_MOVE && ev.which !== 1) {
            eventType = INPUT_END;
        }

        // mouse must be down
        if (!this.pressed) {
            return;
        }

        if (eventType & INPUT_END) {
            this.pressed = false;
        }

        this.callback(this.manager, eventType, {
            pointers: [ev],
            changedPointers: [ev],
            pointerType: INPUT_TYPE_MOUSE,
            srcEvent: ev
        });
    }
});

var POINTER_INPUT_MAP = {
    pointerdown: INPUT_START,
    pointermove: INPUT_MOVE,
    pointerup: INPUT_END,
    pointercancel: INPUT_CANCEL,
    pointerout: INPUT_CANCEL
};

// in IE10 the pointer types is defined as an enum
var IE10_POINTER_TYPE_ENUM = {
    2: INPUT_TYPE_TOUCH,
    3: INPUT_TYPE_PEN,
    4: INPUT_TYPE_MOUSE,
    5: INPUT_TYPE_KINECT // see https://twitter.com/jacobrossi/status/480596438489890816
};

var POINTER_ELEMENT_EVENTS = 'pointerdown';
var POINTER_WINDOW_EVENTS = 'pointermove pointerup pointercancel';

// IE10 has prefixed support, and case-sensitive
if (window.MSPointerEvent && !window.PointerEvent) {
    POINTER_ELEMENT_EVENTS = 'MSPointerDown';
    POINTER_WINDOW_EVENTS = 'MSPointerMove MSPointerUp MSPointerCancel';
}

/**
 * Pointer events input
 * @constructor
 * @extends Input
 */
function PointerEventInput() {
    this.evEl = POINTER_ELEMENT_EVENTS;
    this.evWin = POINTER_WINDOW_EVENTS;

    Input.apply(this, arguments);

    this.store = (this.manager.session.pointerEvents = []);
}

inherit(PointerEventInput, Input, {
    /**
     * handle mouse events
     * @param {Object} ev
     */
    handler: function PEhandler(ev) {
        var store = this.store;
        var removePointer = false;

        var eventTypeNormalized = ev.type.toLowerCase().replace('ms', '');
        var eventType = POINTER_INPUT_MAP[eventTypeNormalized];
        var pointerType = IE10_POINTER_TYPE_ENUM[ev.pointerType] || ev.pointerType;

        var isTouch = (pointerType == INPUT_TYPE_TOUCH);

        // get index of the event in the store
        var storeIndex = inArray(store, ev.pointerId, 'pointerId');

        // start and mouse must be down
        if (eventType & INPUT_START && (ev.button === 0 || isTouch)) {
            if (storeIndex < 0) {
                store.push(ev);
                storeIndex = store.length - 1;
            }
        } else if (eventType & (INPUT_END | INPUT_CANCEL)) {
            removePointer = true;
        }

        // it not found, so the pointer hasn't been down (so it's probably a hover)
        if (storeIndex < 0) {
            return;
        }

        // update the event in the store
        store[storeIndex] = ev;

        this.callback(this.manager, eventType, {
            pointers: store,
            changedPointers: [ev],
            pointerType: pointerType,
            srcEvent: ev
        });

        if (removePointer) {
            // remove from the store
            store.splice(storeIndex, 1);
        }
    }
});

var SINGLE_TOUCH_INPUT_MAP = {
    touchstart: INPUT_START,
    touchmove: INPUT_MOVE,
    touchend: INPUT_END,
    touchcancel: INPUT_CANCEL
};

var SINGLE_TOUCH_TARGET_EVENTS = 'touchstart';
var SINGLE_TOUCH_WINDOW_EVENTS = 'touchstart touchmove touchend touchcancel';

/**
 * Touch events input
 * @constructor
 * @extends Input
 */
function SingleTouchInput() {
    this.evTarget = SINGLE_TOUCH_TARGET_EVENTS;
    this.evWin = SINGLE_TOUCH_WINDOW_EVENTS;
    this.started = false;

    Input.apply(this, arguments);
}

inherit(SingleTouchInput, Input, {
    handler: function TEhandler(ev) {
        var type = SINGLE_TOUCH_INPUT_MAP[ev.type];

        // should we handle the touch events?
        if (type === INPUT_START) {
            this.started = true;
        }

        if (!this.started) {
            return;
        }

        var touches = normalizeSingleTouches.call(this, ev, type);

        // when done, reset the started state
        if (type & (INPUT_END | INPUT_CANCEL) && touches[0].length - touches[1].length === 0) {
            this.started = false;
        }

        this.callback(this.manager, type, {
            pointers: touches[0],
            changedPointers: touches[1],
            pointerType: INPUT_TYPE_TOUCH,
            srcEvent: ev
        });
    }
});

/**
 * @this {TouchInput}
 * @param {Object} ev
 * @param {Number} type flag
 * @returns {undefined|Array} [all, changed]
 */
function normalizeSingleTouches(ev, type) {
    var all = toArray(ev.touches);
    var changed = toArray(ev.changedTouches);

    if (type & (INPUT_END | INPUT_CANCEL)) {
        all = uniqueArray(all.concat(changed), 'identifier', true);
    }

    return [all, changed];
}

var TOUCH_INPUT_MAP = {
    touchstart: INPUT_START,
    touchmove: INPUT_MOVE,
    touchend: INPUT_END,
    touchcancel: INPUT_CANCEL
};

var TOUCH_TARGET_EVENTS = 'touchstart touchmove touchend touchcancel';

/**
 * Multi-user touch events input
 * @constructor
 * @extends Input
 */
function TouchInput() {
    this.evTarget = TOUCH_TARGET_EVENTS;
    this.targetIds = {};

    Input.apply(this, arguments);
}

inherit(TouchInput, Input, {
    handler: function MTEhandler(ev) {
        var type = TOUCH_INPUT_MAP[ev.type];
        var touches = getTouches.call(this, ev, type);
        if (!touches) {
            return;
        }

        this.callback(this.manager, type, {
            pointers: touches[0],
            changedPointers: touches[1],
            pointerType: INPUT_TYPE_TOUCH,
            srcEvent: ev
        });
    }
});

/**
 * @this {TouchInput}
 * @param {Object} ev
 * @param {Number} type flag
 * @returns {undefined|Array} [all, changed]
 */
function getTouches(ev, type) {
    var allTouches = toArray(ev.touches);
    var targetIds = this.targetIds;

    // when there is only one touch, the process can be simplified
    if (type & (INPUT_START | INPUT_MOVE) && allTouches.length === 1) {
        targetIds[allTouches[0].identifier] = true;
        return [allTouches, allTouches];
    }

    var i,
        targetTouches,
        changedTouches = toArray(ev.changedTouches),
        changedTargetTouches = [],
        target = this.target;

    // get target touches from touches
    targetTouches = allTouches.filter(function(touch) {
        return hasParent(touch.target, target);
    });

    // collect touches
    if (type === INPUT_START) {
        i = 0;
        while (i < targetTouches.length) {
            targetIds[targetTouches[i].identifier] = true;
            i++;
        }
    }

    // filter changed touches to only contain touches that exist in the collected target ids
    i = 0;
    while (i < changedTouches.length) {
        if (targetIds[changedTouches[i].identifier]) {
            changedTargetTouches.push(changedTouches[i]);
        }

        // cleanup removed touches
        if (type & (INPUT_END | INPUT_CANCEL)) {
            delete targetIds[changedTouches[i].identifier];
        }
        i++;
    }

    if (!changedTargetTouches.length) {
        return;
    }

    return [
        // merge targetTouches with changedTargetTouches so it contains ALL touches, including 'end' and 'cancel'
        uniqueArray(targetTouches.concat(changedTargetTouches), 'identifier', true),
        changedTargetTouches
    ];
}

/**
 * Combined touch and mouse input
 *
 * Touch has a higher priority then mouse, and while touching no mouse events are allowed.
 * This because touch devices also emit mouse events while doing a touch.
 *
 * @constructor
 * @extends Input
 */

var DEDUP_TIMEOUT = 2500;
var DEDUP_DISTANCE = 25;

function TouchMouseInput() {
    Input.apply(this, arguments);

    var handler = bindFn(this.handler, this);
    this.touch = new TouchInput(this.manager, handler);
    this.mouse = new MouseInput(this.manager, handler);

    this.primaryTouch = null;
    this.lastTouches = [];
}

inherit(TouchMouseInput, Input, {
    /**
     * handle mouse and touch events
     * @param {Hammer} manager
     * @param {String} inputEvent
     * @param {Object} inputData
     */
    handler: function TMEhandler(manager, inputEvent, inputData) {
        var isTouch = (inputData.pointerType == INPUT_TYPE_TOUCH),
            isMouse = (inputData.pointerType == INPUT_TYPE_MOUSE);

        if (isMouse && inputData.sourceCapabilities && inputData.sourceCapabilities.firesTouchEvents) {
            return;
        }

        // when we're in a touch event, record touches to  de-dupe synthetic mouse event
        if (isTouch) {
            recordTouches.call(this, inputEvent, inputData);
        } else if (isMouse && isSyntheticEvent.call(this, inputData)) {
            return;
        }

        this.callback(manager, inputEvent, inputData);
    },

    /**
     * remove the event listeners
     */
    destroy: function destroy() {
        this.touch.destroy();
        this.mouse.destroy();
    }
});

function recordTouches(eventType, eventData) {
    if (eventType & INPUT_START) {
        this.primaryTouch = eventData.changedPointers[0].identifier;
        setLastTouch.call(this, eventData);
    } else if (eventType & (INPUT_END | INPUT_CANCEL)) {
        setLastTouch.call(this, eventData);
    }
}

function setLastTouch(eventData) {
    var touch = eventData.changedPointers[0];

    if (touch.identifier === this.primaryTouch) {
        var lastTouch = {x: touch.clientX, y: touch.clientY};
        this.lastTouches.push(lastTouch);
        var lts = this.lastTouches;
        var removeLastTouch = function() {
            var i = lts.indexOf(lastTouch);
            if (i > -1) {
                lts.splice(i, 1);
            }
        };
        setTimeout(removeLastTouch, DEDUP_TIMEOUT);
    }
}

function isSyntheticEvent(eventData) {
    var x = eventData.srcEvent.clientX, y = eventData.srcEvent.clientY;
    for (var i = 0; i < this.lastTouches.length; i++) {
        var t = this.lastTouches[i];
        var dx = Math.abs(x - t.x), dy = Math.abs(y - t.y);
        if (dx <= DEDUP_DISTANCE && dy <= DEDUP_DISTANCE) {
            return true;
        }
    }
    return false;
}

var PREFIXED_TOUCH_ACTION = prefixed(TEST_ELEMENT.style, 'touchAction');
var NATIVE_TOUCH_ACTION = PREFIXED_TOUCH_ACTION !== undefined;

// magical touchAction value
var TOUCH_ACTION_COMPUTE = 'compute';
var TOUCH_ACTION_AUTO = 'auto';
var TOUCH_ACTION_MANIPULATION = 'manipulation'; // not implemented
var TOUCH_ACTION_NONE = 'none';
var TOUCH_ACTION_PAN_X = 'pan-x';
var TOUCH_ACTION_PAN_Y = 'pan-y';
var TOUCH_ACTION_MAP = getTouchActionProps();

/**
 * Touch Action
 * sets the touchAction property or uses the js alternative
 * @param {Manager} manager
 * @param {String} value
 * @constructor
 */
function TouchAction(manager, value) {
    this.manager = manager;
    this.set(value);
}

TouchAction.prototype = {
    /**
     * set the touchAction value on the element or enable the polyfill
     * @param {String} value
     */
    set: function(value) {
        // find out the touch-action by the event handlers
        if (value == TOUCH_ACTION_COMPUTE) {
            value = this.compute();
        }

        if (NATIVE_TOUCH_ACTION && this.manager.element.style && TOUCH_ACTION_MAP[value]) {
            this.manager.element.style[PREFIXED_TOUCH_ACTION] = value;
        }
        this.actions = value.toLowerCase().trim();
    },

    /**
     * just re-set the touchAction value
     */
    update: function() {
        this.set(this.manager.options.touchAction);
    },

    /**
     * compute the value for the touchAction property based on the recognizer's settings
     * @returns {String} value
     */
    compute: function() {
        var actions = [];
        each(this.manager.recognizers, function(recognizer) {
            if (boolOrFn(recognizer.options.enable, [recognizer])) {
                actions = actions.concat(recognizer.getTouchAction());
            }
        });
        return cleanTouchActions(actions.join(' '));
    },

    /**
     * this method is called on each input cycle and provides the preventing of the browser behavior
     * @param {Object} input
     */
    preventDefaults: function(input) {
        var srcEvent = input.srcEvent;
        var direction = input.offsetDirection;

        // if the touch action did prevented once this session
        if (this.manager.session.prevented) {
            srcEvent.preventDefault();
            return;
        }

        var actions = this.actions;
        var hasNone = inStr(actions, TOUCH_ACTION_NONE) && !TOUCH_ACTION_MAP[TOUCH_ACTION_NONE];
        var hasPanY = inStr(actions, TOUCH_ACTION_PAN_Y) && !TOUCH_ACTION_MAP[TOUCH_ACTION_PAN_Y];
        var hasPanX = inStr(actions, TOUCH_ACTION_PAN_X) && !TOUCH_ACTION_MAP[TOUCH_ACTION_PAN_X];

        if (hasNone) {
            //do not prevent defaults if this is a tap gesture

            var isTapPointer = input.pointers.length === 1;
            var isTapMovement = input.distance < 2;
            var isTapTouchTime = input.deltaTime < 250;

            if (isTapPointer && isTapMovement && isTapTouchTime) {
                return;
            }
        }

        if (hasPanX && hasPanY) {
            // `pan-x pan-y` means browser handles all scrolling/panning, do not prevent
            return;
        }

        if (hasNone ||
            (hasPanY && direction & DIRECTION_HORIZONTAL) ||
            (hasPanX && direction & DIRECTION_VERTICAL)) {
            return this.preventSrc(srcEvent);
        }
    },

    /**
     * call preventDefault to prevent the browser's default behavior (scrolling in most cases)
     * @param {Object} srcEvent
     */
    preventSrc: function(srcEvent) {
        this.manager.session.prevented = true;
        srcEvent.preventDefault();
    }
};

/**
 * when the touchActions are collected they are not a valid value, so we need to clean things up. *
 * @param {String} actions
 * @returns {*}
 */
function cleanTouchActions(actions) {
    // none
    if (inStr(actions, TOUCH_ACTION_NONE)) {
        return TOUCH_ACTION_NONE;
    }

    var hasPanX = inStr(actions, TOUCH_ACTION_PAN_X);
    var hasPanY = inStr(actions, TOUCH_ACTION_PAN_Y);

    // if both pan-x and pan-y are set (different recognizers
    // for different directions, e.g. horizontal pan but vertical swipe?)
    // we need none (as otherwise with pan-x pan-y combined none of these
    // recognizers will work, since the browser would handle all panning
    if (hasPanX && hasPanY) {
        return TOUCH_ACTION_NONE;
    }

    // pan-x OR pan-y
    if (hasPanX || hasPanY) {
        return hasPanX ? TOUCH_ACTION_PAN_X : TOUCH_ACTION_PAN_Y;
    }

    // manipulation
    if (inStr(actions, TOUCH_ACTION_MANIPULATION)) {
        return TOUCH_ACTION_MANIPULATION;
    }

    return TOUCH_ACTION_AUTO;
}

function getTouchActionProps() {
    if (!NATIVE_TOUCH_ACTION) {
        return false;
    }
    var touchMap = {};
    var cssSupports = window.CSS && window.CSS.supports;
    ['auto', 'manipulation', 'pan-y', 'pan-x', 'pan-x pan-y', 'none'].forEach(function(val) {

        // If css.supports is not supported but there is native touch-action assume it supports
        // all values. This is the case for IE 10 and 11.
        touchMap[val] = cssSupports ? window.CSS.supports('touch-action', val) : true;
    });
    return touchMap;
}

/**
 * Recognizer flow explained; *
 * All recognizers have the initial state of POSSIBLE when a input session starts.
 * The definition of a input session is from the first input until the last input, with all it's movement in it. *
 * Example session for mouse-input: mousedown -> mousemove -> mouseup
 *
 * On each recognizing cycle (see Manager.recognize) the .recognize() method is executed
 * which determines with state it should be.
 *
 * If the recognizer has the state FAILED, CANCELLED or RECOGNIZED (equals ENDED), it is reset to
 * POSSIBLE to give it another change on the next cycle.
 *
 *               Possible
 *                  |
 *            +-----+---------------+
 *            |                     |
 *      +-----+-----+               |
 *      |           |