draggabilly.js

/*!
 * Draggabilly PACKAGED v1.2.4
 * Make that shiz draggable
 * http://draggabilly.desandro.com
 * MIT license
 */

/**
 * Bridget makes jQuery widgets
 * v1.1.0
 * MIT license
 */

( function( window ) {



// -------------------------- utils -------------------------- //

var slice = Array.prototype.slice;

function noop() {}

// -------------------------- definition -------------------------- //

function defineBridget( $ ) {

// bail if no jQuery
if ( !$ ) {
  return;
}

// -------------------------- addOptionMethod -------------------------- //

/**
 * adds option method -> $().plugin('option', {...})
 * @param {Function} PluginClass - constructor class
 */
function addOptionMethod( PluginClass ) {
  // don't overwrite original option method
  if ( PluginClass.prototype.option ) {
    return;
  }

  // option setter
  PluginClass.prototype.option = function( opts ) {
    // bail out if not an object
    if ( !$.isPlainObject( opts ) ){
      return;
    }
    this.options = $.extend( true, this.options, opts );
  };
}

// -------------------------- plugin bridge -------------------------- //

// helper function for logging errors
// $.error breaks jQuery chaining
var logError = typeof console === 'undefined' ? noop :
  function( message ) {
    console.error( message );
  };

/**
 * jQuery plugin bridge, access methods like $elem.plugin('method')
 * @param {String} namespace - plugin name
 * @param {Function} PluginClass - constructor class
 */
function bridge( namespace, PluginClass ) {
  // add to jQuery fn namespace
  $.fn[ namespace ] = function( options ) {
    if ( typeof options === 'string' ) {
      // call plugin method when first argument is a string
      // get arguments for method
      var args = slice.call( arguments, 1 );

      for ( var i=0, len = this.length; i < len; i++ ) {
        var elem = this[i];
        var instance = $.data( elem, namespace );
        if ( !instance ) {
          logError( "cannot call methods on " + namespace + " prior to initialization; " +
            "attempted to call '" + options + "'" );
          continue;
        }
        if ( !$.isFunction( instance[options] ) || options.charAt(0) === '_' ) {
          logError( "no such method '" + options + "' for " + namespace + " instance" );
          continue;
        }

        // trigger method with arguments
        var returnValue = instance[ options ].apply( instance, args );

        // break look and return first value if provided
        if ( returnValue !== undefined ) {
          return returnValue;
        }
      }
      // return this if no return value
      return this;
    } else {
      return this.each( function() {
        var instance = $.data( this, namespace );
        if ( instance ) {
          // apply options & init
          instance.option( options );
          instance._init();
        } else {
          // initialize new instance
          instance = new PluginClass( this, options );
          $.data( this, namespace, instance );
        }
      });
    }
  };

}

// -------------------------- bridget -------------------------- //

/**
 * converts a Prototypical class into a proper jQuery plugin
 *   the class must have a ._init method
 * @param {String} namespace - plugin name, used in $().pluginName
 * @param {Function} PluginClass - constructor class
 */
$.bridget = function( namespace, PluginClass ) {
  addOptionMethod( PluginClass );
  bridge( namespace, PluginClass );
};

return $.bridget;

}

// transport
if ( typeof define === 'function' && define.amd ) {
  // AMD
  define( 'jquery-bridget/jquery.bridget',[ 'jquery' ], defineBridget );
} else if ( typeof exports === 'object' ) {
  defineBridget( require('jquery') );
} else {
  // get jquery from browser global
  defineBridget( window.jQuery );
}

})( window );

/*!
 * classie v1.0.1
 * class helper functions
 * from bonzo https://github.com/ded/bonzo
 * MIT license
 * 
 * classie.has( elem, 'my-class' ) -> true/false
 * classie.add( elem, 'my-new-class' )
 * classie.remove( elem, 'my-unwanted-class' )
 * classie.toggle( elem, 'my-class' )
 */

/*jshint browser: true, strict: true, undef: true, unused: true */
/*global define: false, module: false */

( function( window ) {



// class helper functions from bonzo https://github.com/ded/bonzo

function classReg( className ) {
  return new RegExp("(^|\\s+)" + className + "(\\s+|$)");
}

// classList support for class management
// altho to be fair, the api sucks because it won't accept multiple classes at once
var hasClass, addClass, removeClass;

if ( 'classList' in document.documentElement ) {
  hasClass = function( elem, c ) {
    return elem.classList.contains( c );
  };
  addClass = function( elem, c ) {
    elem.classList.add( c );
  };
  removeClass = function( elem, c ) {
    elem.classList.remove( c );
  };
}
else {
  hasClass = function( elem, c ) {
    return classReg( c ).test( elem.className );
  };
  addClass = function( elem, c ) {
    if ( !hasClass( elem, c ) ) {
      elem.className = elem.className + ' ' + c;
    }
  };
  removeClass = function( elem, c ) {
    elem.className = elem.className.replace( classReg( c ), ' ' );
  };
}

function toggleClass( elem, c ) {
  var fn = hasClass( elem, c ) ? removeClass : addClass;
  fn( elem, c );
}

var classie = {
  // full names
  hasClass: hasClass,
  addClass: addClass,
  removeClass: removeClass,
  toggleClass: toggleClass,
  // short names
  has: hasClass,
  add: addClass,
  remove: removeClass,
  toggle: toggleClass
};

// transport
if ( typeof define === 'function' && define.amd ) {
  // AMD
  define( 'classie/classie',classie );
} else if ( typeof exports === 'object' ) {
  // CommonJS
  module.exports = classie;
} else {
  // browser global
  window.classie = classie;
}

})( window );

/*!
 * getStyleProperty v1.0.4
 * original by kangax
 * http://perfectionkills.com/feature-testing-css-properties/
 * MIT license
 */

/*jshint browser: true, strict: true, undef: true */
/*global define: false, exports: false, module: false */

( function( window ) {



var prefixes = 'Webkit Moz ms Ms O'.split(' ');
var docElemStyle = document.documentElement.style;

function getStyleProperty( propName ) {
  if ( !propName ) {
    return;
  }

  // test standard property first
  if ( typeof docElemStyle[ propName ] === 'string' ) {
    return propName;
  }

  // capitalize
  propName = propName.charAt(0).toUpperCase() + propName.slice(1);

  // test vendor specific properties
  var prefixed;
  for ( var i=0, len = prefixes.length; i < len; i++ ) {
    prefixed = prefixes[i] + propName;
    if ( typeof docElemStyle[ prefixed ] === 'string' ) {
      return prefixed;
    }
  }
}

// transport
if ( typeof define === 'function' && define.amd ) {
  // AMD
  define( 'get-style-property/get-style-property',[],function() {
    return getStyleProperty;
  });
} else if ( typeof exports === 'object' ) {
  // CommonJS for Component
  module.exports = getStyleProperty;
} else {
  // browser global
  window.getStyleProperty = getStyleProperty;
}

})( window );

/*!
 * getSize v1.2.2
 * measure size of elements
 * MIT license
 */

/*jshint browser: true, strict: true, undef: true, unused: true */
/*global define: false, exports: false, require: false, module: false, console: false */

( function( window, undefined ) {



// -------------------------- helpers -------------------------- //

// get a number from a string, not a percentage
function getStyleSize( value ) {
  var num = parseFloat( value );
  // not a percent like '100%', and a number
  var isValid = value.indexOf('%') === -1 && !isNaN( num );
  return isValid && num;
}

function noop() {}

var logError = typeof console === 'undefined' ? noop :
  function( message ) {
    console.error( message );
  };

// -------------------------- measurements -------------------------- //

var measurements = [
  'paddingLeft',
  'paddingRight',
  'paddingTop',
  'paddingBottom',
  'marginLeft',
  'marginRight',
  'marginTop',
  'marginBottom',
  'borderLeftWidth',
  'borderRightWidth',
  'borderTopWidth',
  'borderBottomWidth'
];

function getZeroSize() {
  var size = {
    width: 0,
    height: 0,
    innerWidth: 0,
    innerHeight: 0,
    outerWidth: 0,
    outerHeight: 0
  };
  for ( var i=0, len = measurements.length; i < len; i++ ) {
    var measurement = measurements[i];
    size[ measurement ] = 0;
  }
  return size;
}



function defineGetSize( getStyleProperty ) {

// -------------------------- setup -------------------------- //

var isSetup = false;

var getStyle, boxSizingProp, isBoxSizeOuter;

/**
 * setup vars and functions
 * do it on initial getSize(), rather than on script load
 * For Firefox bug https://bugzilla.mozilla.org/show_bug.cgi?id=548397
 */
function setup() {
  // setup once
  if ( isSetup ) {
    return;
  }
  isSetup = true;

  var getComputedStyle = window.getComputedStyle;
  getStyle = ( function() {
    var getStyleFn = getComputedStyle ?
      function( elem ) {
        return getComputedStyle( elem, null );
      } :
      function( elem ) {
        return elem.currentStyle;
      };

      return function getStyle( elem ) {
        var style = getStyleFn( elem );
        if ( !style ) {
          logError( 'Style returned ' + style +
            '. Are you running this code in a hidden iframe on Firefox? ' +
            'See http://bit.ly/getsizebug1' );
        }
        return style;
      };
  })();

  // -------------------------- box sizing -------------------------- //

  boxSizingProp = getStyleProperty('boxSizing');

  /**
   * WebKit measures the outer-width on style.width on border-box elems
   * IE & Firefox measures the inner-width
   */
  if ( boxSizingProp ) {
    var div = document.createElement('div');
    div.style.width = '200px';
    div.style.padding = '1px 2px 3px 4px';
    div.style.borderStyle = 'solid';
    div.style.borderWidth = '1px 2px 3px 4px';
    div.style[ boxSizingProp ] = 'border-box';

    var body = document.body || document.documentElement;
    body.appendChild( div );
    var style = getStyle( div );

    isBoxSizeOuter = getStyleSize( style.width ) === 200;
    body.removeChild( div );
  }

}

// -------------------------- getSize -------------------------- //

function getSize( elem ) {
  setup();

  // use querySeletor if elem is string
  if ( typeof elem === 'string' ) {
    elem = document.querySelector( elem );
  }

  // do not proceed on non-objects
  if ( !elem || typeof elem !== 'object' || !elem.nodeType ) {
    return;
  }

  var style = getStyle( elem );

  // if hidden, everything is 0
  if ( style.display === 'none' ) {
    return getZeroSize();
  }

  var size = {};
  size.width = elem.offsetWidth;
  size.height = elem.offsetHeight;

  var isBorderBox = size.isBorderBox = !!( boxSizingProp &&
    style[ boxSizingProp ] && style[ boxSizingProp ] === 'border-box' );

  // get all measurements
  for ( var i=0, len = measurements.length; i < len; i++ ) {
    var measurement = measurements[i];
    var value = style[ measurement ];
    value = mungeNonPixel( elem, value );
    var num = parseFloat( value );
    // any 'auto', 'medium' value will be 0
    size[ measurement ] = !isNaN( num ) ? num : 0;
  }

  var paddingWidth = size.paddingLeft + size.paddingRight;
  var paddingHeight = size.paddingTop + size.paddingBottom;
  var marginWidth = size.marginLeft + size.marginRight;
  var marginHeight = size.marginTop + size.marginBottom;
  var borderWidth = size.borderLeftWidth + size.borderRightWidth;
  var borderHeight = size.borderTopWidth + size.borderBottomWidth;

  var isBorderBoxSizeOuter = isBorderBox && isBoxSizeOuter;

  // overwrite width and height if we can get it from style
  var styleWidth = getStyleSize( style.width );
  if ( styleWidth !== false ) {
    size.width = styleWidth +
      // add padding and border unless it's already including it
      ( isBorderBoxSizeOuter ? 0 : paddingWidth + borderWidth );
  }

  var styleHeight = getStyleSize( style.height );
  if ( styleHeight !== false ) {
    size.height = styleHeight +
      // add padding and border unless it's already including it
      ( isBorderBoxSizeOuter ? 0 : paddingHeight + borderHeight );
  }

  size.innerWidth = size.width - ( paddingWidth + borderWidth );
  size.innerHeight = size.height - ( paddingHeight + borderHeight );

  size.outerWidth = size.width + marginWidth;
  size.outerHeight = size.height + marginHeight;

  return size;
}

// IE8 returns percent values, not pixels
// taken from jQuery's curCSS
function mungeNonPixel( elem, value ) {
  // IE8 and has percent value
  if ( window.getComputedStyle || value.indexOf('%') === -1 ) {
    return value;
  }
  var style = elem.style;
  // Remember the original values
  var left = style.left;
  var rs = elem.runtimeStyle;
  var rsLeft = rs && rs.left;

  // Put in the new values to get a computed value out
  if ( rsLeft ) {
    rs.left = elem.currentStyle.left;
  }
  style.left = value;
  value = style.pixelLeft;

  // Revert the changed values
  style.left = left;
  if ( rsLeft ) {
    rs.left = rsLeft;
  }

  return value;
}

return getSize;

}

// transport
if ( typeof define === 'function' && define.amd ) {
  // AMD for RequireJS
  define( 'get-size/get-size',[ 'get-style-property/get-style-property' ], defineGetSize );
} else if ( typeof exports === 'object' ) {
  // CommonJS for Component
  module.exports = defineGetSize( require('desandro-get-style-property') );
} else {
  // browser global
  window.getSize = defineGetSize( window.getStyleProperty );
}

})( window );

/*!
 * eventie v1.0.6
 * event binding helper
 *   eventie.bind( elem, 'click', myFn )
 *   eventie.unbind( elem, 'click', myFn )
 * MIT license
 */

/*jshint browser: true, undef: true, unused: true */
/*global define: false, module: false */

( function( window ) {



var docElem = document.documentElement;

var bind = function() {};

function getIEEvent( obj ) {
  var event = window.event;
  // add event.target
  event.target = event.target || event.srcElement || obj;
  return event;
}

if ( docElem.addEventListener ) {
  bind = function( obj, type, fn ) {
    obj.addEventListener( type, fn, false );
  };
} else if ( docElem.attachEvent ) {
  bind = function( obj, type, fn ) {
    obj[ type + fn ] = fn.handleEvent ?
      function() {
        var event = getIEEvent( obj );
        fn.handleEvent.call( fn, event );
      } :
      function() {
        var event = getIEEvent( obj );
        fn.call( obj, event );
      };
    obj.attachEvent( "on" + type, obj[ type + fn ] );
  };
}

var unbind = function() {};

if ( docElem.removeEventListener ) {
  unbind = function( obj, type, fn ) {
    obj.removeEventListener( type, fn, false );
  };
} else if ( docElem.detachEvent ) {
  unbind = function( obj, type, fn ) {
    obj.detachEvent( "on" + type, obj[ type + fn ] );
    try {
      delete obj[ type + fn ];
    } catch ( err ) {
      // can't delete window object properties
      obj[ type + fn ] = undefined;
    }
  };
}

var eventie = {
  bind: bind,
  unbind: unbind
};

// ----- module definition ----- //

if ( typeof define === 'function' && define.amd ) {
  // AMD
  define( 'eventie/eventie',eventie );
} else if ( typeof exports === 'object' ) {
  // CommonJS
  module.exports = eventie;
} else {
  // browser global
  window.eventie = eventie;
}

})( window );

/*!
 * EventEmitter v4.2.11 - git.io/ee
 * Unlicense - http://unlicense.org/
 * Oliver Caldwell - http://oli.me.uk/
 * @preserve
 */

;(function () {
    

    /**
     * Class for managing events.
     * Can be extended to provide event functionality in other classes.
     *
     * @class EventEmitter Manages event registering and emitting.
     */
    function EventEmitter() {}

    // Shortcuts to improve speed and size
    var proto = EventEmitter.prototype;
    var exports = this;
    var originalGlobalValue = exports.EventEmitter;

    /**
     * Finds the index of the listener for the event in its storage array.
     *
     * @param {Function[]} listeners Array of listeners to search through.
     * @param {Function} listener Method to look for.
     * @return {Number} Index of the specified listener, -1 if not found
     * @api private
     */
    function indexOfListener(listeners, listener) {
        var i = listeners.length;
        while (i--) {
            if (listeners[i].listener === listener) {
                return i;
            }
        }

        return -1;
    }

    /**
     * Alias a method while keeping the context correct, to allow for overwriting of target method.
     *
     * @param {String} name The name of the target method.
     * @return {Function} The aliased method
     * @api private
     */
    function alias(name) {
        return function aliasClosure() {
            return this[name].apply(this, arguments);
        };
    }

    /**
     * Returns the listener array for the specified event.
     * Will initialise the event object and listener arrays if required.
     * Will return an object if you use a regex search. The object contains keys for each matched event. So /ba[rz]/ might return an object containing bar and baz. But only if you have either defined them with defineEvent or added some listeners to them.
     * Each property in the object response is an array of listener functions.
     *
     * @param {String|RegExp} evt Name of the event to return the listeners from.
     * @return {Function[]|Object} All listener functions for the event.
     */
    proto.getListeners = function getListeners(evt) {
        var events = this._getEvents();
        var response;
        var key;

        // Return a concatenated array of all matching events if
        // the selector is a regular expression.
        if (evt instanceof RegExp) {
            response = {};
            for (key in events) {
                if (events.hasOwnProperty(key) && evt.test(key)) {
                    response[key] = events[key];
                }
            }
        }
        else {
            response = events[evt] || (events[evt] = []);
        }

        return response;
    };

    /**
     * Takes a list of listener objects and flattens it into a list of listener functions.
     *
     * @param {Object[]} listeners Raw listener objects.
     * @return {Function[]} Just the listener functions.
     */
    proto.flattenListeners = function flattenListeners(listeners) {
        var flatListeners = [];
        var i;

        for (i = 0; i < listeners.length; i += 1) {
            flatListeners.push(listeners[i].listener);
        }

        return flatListeners;
    };

    /**
     * Fetches the requested listeners via getListeners but will always return the results inside an object. This is mainly for internal use but others may find it useful.
     *
     * @param {String|RegExp} evt Name of the event to return the listeners from.
     * @return {Object} All listener functions for an event in an object.
     */
    proto.getListenersAsObject = function getListenersAsObject(evt) {
        var listeners = this.getListeners(evt);
        var response;

        if (listeners instanceof Array) {
            response = {};
            response[evt] = listeners;
        }

        return response || listeners;
    };

    /**
     * Adds a listener function to the specified event.
     * The listener will not be added if it is a duplicate.
     * If the listener returns true then it will be removed after it is called.
     * If you pass a regular expression as the event name then the listener will be added to all events that match it.
     *
     * @param {String|RegExp} evt Name of the event to attach the listener to.
     * @param {Function} listener Method to be called when the event is emitted. If the function returns true then it will be removed after calling.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.addListener = function addListener(evt, listener) {
        var listeners = this.getListenersAsObject(evt);
        var listenerIsWrapped = typeof listener === 'object';
        var key;

        for (key in listeners) {
            if (listeners.hasOwnProperty(key) && indexOfListener(listeners[key], listener) === -1) {
                listeners[key].push(listenerIsWrapped ? listener : {
                    listener: listener,
                    once: false
                });
            }
        }

        return this;
    };

    /**
     * Alias of addListener
     */
    proto.on = alias('addListener');

    /**
     * Semi-alias of addListener. It will add a listener that will be
     * automatically removed after its first execution.
     *
     * @param {String|RegExp} evt Name of the event to attach the listener to.
     * @param {Function} listener Method to be called when the event is emitted. If the function returns true then it will be removed after calling.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.addOnceListener = function addOnceListener(evt, listener) {
        return this.addListener(evt, {
            listener: listener,
            once: true
        });
    };

    /**
     * Alias of addOnceListener.
     */
    proto.once = alias('addOnceListener');

    /**
     * Defines an event name. This is required if you want to use a regex to add a listener to multiple events at once. If you don't do this then how do you expect it to know what event to add to? Should it just add to every possible match for a regex? No. That is scary and bad.
     * You need to tell it what event names should be matched by a regex.
     *
     * @param {String} evt Name of the event to create.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.defineEvent = function defineEvent(evt) {
        this.getListeners(evt);
        return this;
    };

    /**
     * Uses defineEvent to define multiple events.
     *
     * @param {String[]} evts An array of event names to define.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.defineEvents = function defineEvents(evts) {
        for (var i = 0; i < evts.length; i += 1) {
            this.defineEvent(evts[i]);
        }
        return this;
    };

    /**
     * Removes a listener function from the specified event.
     * When passed a regular expression as the event name, it will remove the listener from all events that match it.
     *
     * @param {String|RegExp} evt Name of the event to remove the listener from.
     * @param {Function} listener Method to remove from the event.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.removeListener = function removeListener(evt, listener) {
        var listeners = this.getListenersAsObject(evt);
        var index;
        var key;

        for (key in listeners) {
            if (listeners.hasOwnProperty(key)) {
                index = indexOfListener(listeners[key], listener);

                if (index !== -1) {
                    listeners[key].splice(index, 1);
                }
            }
        }

        return this;
    };

    /**
     * Alias of removeListener
     */
    proto.off = alias('removeListener');

    /**
     * Adds listeners in bulk using the manipulateListeners method.
     * If you pass an object as the second argument you can add to multiple events at once. The object should contain key value pairs of events and listeners or listener arrays. You can also pass it an event name and an array of listeners to be added.
     * You can also pass it a regular expression to add the array of listeners to all events that match it.
     * Yeah, this function does quite a bit. That's probably a bad thing.
     *
     * @param {String|Object|RegExp} evt An event name if you will pass an array of listeners next. An object if you wish to add to multiple events at once.
     * @param {Function[]} [listeners] An optional array of listener functions to add.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.addListeners = function addListeners(evt, listeners) {
        // Pass through to manipulateListeners
        return this.manipulateListeners(false, evt, listeners);
    };

    /**
     * Removes listeners in bulk using the manipulateListeners method.
     * If you pass an object as the second argument you can remove from multiple events at once. The object should contain key value pairs of events and listeners or listener arrays.
     * You can also pass it an event name and an array of listeners to be removed.
     * You can also pass it a regular expression to remove the listeners from all events that match it.
     *
     * @param {String|Object|RegExp} evt An event name if you will pass an array of listeners next. An object if you wish to remove from multiple events at once.
     * @param {Function[]} [listeners] An optional array of listener functions to remove.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.removeListeners = function removeListeners(evt, listeners) {
        // Pass through to manipulateListeners
        return this.manipulateListeners(true, evt, listeners);
    };

    /**
     * Edits listeners in bulk. The addListeners and removeListeners methods both use this to do their job. You should really use those instead, this is a little lower level.
     * The first argument will determine if the listeners are removed (true) or added (false).
     * If you pass an object as the second argument you can add/remove from multiple events at once. The object should contain key value pairs of events and listeners or listener arrays.
     * You can also pass it an event name and an array of listeners to be added/removed.
     * You can also pass it a regular expression to manipulate the listeners of all events that match it.
     *
     * @param {Boolean} remove True if you want to remove listeners, false if you want to add.
     * @param {String|Object|RegExp} evt An event name if you will pass an array of listeners next. An object if you wish to add/remove from multiple events at once.
     * @param {Function[]} [listeners] An optional array of listener functions to add/remove.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.manipulateListeners = function manipulateListeners(remove, evt, listeners) {
        var i;
        var value;
        var single = remove ? this.removeListener : this.addListener;
        var multiple = remove ? this.removeListeners : this.addListeners;

        // If evt is an object then pass each of its properties to this method
        if (typeof evt === 'object' && !(evt instanceof RegExp)) {
            for (i in evt) {
                if (evt.hasOwnProperty(i) && (value = evt[i])) {
                    // Pass the single listener straight through to the singular method
                    if (typeof value === 'function') {
                        single.call(this, i, value);
                    }
                    else {
                        // Otherwise pass back to the multiple function
                        multiple.call(this, i, value);
                    }
                }
            }
        }
        else {
            // So evt must be a string
            // And listeners must be an array of listeners
            // Loop over it and pass each one to the multiple method
            i = listeners.length;
            while (i--) {
                single.call(this, evt, listeners[i]);
            }
        }

        return this;
    };

    /**
     * Removes all listeners from a specified event.
     * If you do not specify an event then all listeners will be removed.
     * That means every event will be emptied.
     * You can also pass a regex to remove all events that match it.
     *
     * @param {String|RegExp} [evt] Optional name of the event to remove all listeners for. Will remove from every event if not passed.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.removeEvent = function removeEvent(evt) {
        var type = typeof evt;
        var events = this._getEvents();
        var key;

        // Remove different things depending on the state of evt
        if (type === 'string') {
            // Remove all listeners for the specified event
            delete events[evt];
        }
        else if (evt instanceof RegExp) {
            // Remove all events matching the regex.
            for (key in events) {
                if (events.hasOwnProperty(key) && evt.test(key)) {
                    delete events[key];
                }
            }
        }
        else {
            // Remove all listeners in all events
            delete this._events;
        }

        return this;
    };

    /**
     * Alias of removeEvent.
     *
     * Added to mirror the node API.
     */
    proto.removeAllListeners = alias('removeEvent');

    /**
     * Emits an event of your choice.
     * When emitted, every listener attached to that event will be executed.
     * If you pass the optional argument array then those arguments will be passed to every listener upon execution.
     * Because it uses `apply`, your array of arguments will be passed as if you wrote them out separately.
     * So they will not arrive within the array on the other side, they will be separate.
     * You can also pass a regular expression to emit to all events that match it.
     *
     * @param {String|RegExp} evt Name of the event to emit and execute listeners for.
     * @param {Array} [args] Optional array of arguments to be passed to each listener.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.emitEvent = function emitEvent(evt, args) {
        var listeners = this.getListenersAsObject(evt);
        var listener;
        var i;
        var key;
        var response;

        for (key in listeners) {
            if (listeners.hasOwnProperty(key)) {
                i = listeners[key].length;

                while (i--) {
                    // If the listener returns true then it shall be removed from the event
                    // The function is executed either with a basic call or an apply if there is an args array
                    listener = listeners[key][i];

                    if (listener.once === true) {
                        this.removeListener(evt, listener.listener);
                    }

                    response = listener.listener.apply(this, args || []);

                    if (response === this._getOnceReturnValue()) {
                        this.removeListener(evt, listener.listener);
                    }
                }
            }
        }

        return this;
    };

    /**
     * Alias of emitEvent
     */
    proto.trigger = alias('emitEvent');

    /**
     * Subtly different from emitEvent in that it will pass its arguments on to the listeners, as opposed to taking a single array of arguments to pass on.
     * As with emitEvent, you can pass a regex in place of the event name to emit to all events that match it.
     *
     * @param {String|RegExp} evt Name of the event to emit and execute listeners for.
     * @param {...*} Optional additional arguments to be passed to each listener.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.emit = function emit(evt) {
        var args = Array.prototype.slice.call(arguments, 1);
        return this.emitEvent(evt, args);
    };

    /**
     * Sets the current value to check against when executing listeners. If a
     * listeners return value matches the one set here then it will be removed
     * after execution. This value defaults to true.
     *
     * @param {*} value The new value to check for when executing listeners.
     * @return {Object} Current instance of EventEmitter for chaining.
     */
    proto.setOnceReturnValue = function setOnceReturnValue(value) {
        this._onceReturnValue = value;
        return this;
    };

    /**
     * Fetches the current value to check against when executing listeners. If
     * the listeners return value matches this one then it should be removed
     * automatically. It will return true by default.
     *
     * @return {*|Boolean} The current value to check for or the default, true.
     * @api private
     */
    proto._getOnceReturnValue = function _getOnceReturnValue() {
        if (this.hasOwnProperty('_onceReturnValue')) {
            return this._onceReturnValue;
        }
        else {
            return true;
        }
    };

    /**
     * Fetches the events object and creates one if required.
     *
     * @return {Object} The events storage object.
     * @api private
     */
    proto._getEvents = function _getEvents() {
        return this._events || (this._events = {});
    };

    /**
     * Reverts the global {@link EventEmitter} to its previous value and returns a reference to this version.
     *
     * @return {Function} Non conflicting EventEmitter class.
     */
    EventEmitter.noConflict = function noConflict() {
        exports.EventEmitter = originalGlobalValue;
        return EventEmitter;
    };

    // Expose the class either via AMD, CommonJS or the global object
    if (typeof define === 'function' && define.amd) {
        define('eventEmitter/EventEmitter',[],function () {
            return EventEmitter;
        });
    }
    else if (typeof module === 'object' && module.exports){
        module.exports = EventEmitter;
    }
    else {
        exports.EventEmitter = EventEmitter;
    }
}.call(this));

/*!
 * Unipointer v1.1.0
 * base class for doing one thing with pointer event
 * MIT license
 */

/*jshint browser: true, undef: true, unused: true, strict: true */
/*global define: false, module: false, require: false */

( function( window, factory ) {
  
  // universal module definition

  if ( typeof define == 'function' && define.amd ) {
    // AMD
    define( 'unipointer/unipointer',[
      'eventEmitter/EventEmitter',
      'eventie/eventie'
    ], function( EventEmitter, eventie ) {
      return factory( window, EventEmitter, eventie );
    });
  } else if ( typeof exports == 'object' ) {
    // CommonJS
    module.exports = factory(
      window,
      require('wolfy87-eventemitter'),
      require('eventie')
    );
  } else {
    // browser global
    window.Unipointer = factory(
      window,
      window.EventEmitter,
      window.eventie
    );
  }

}( window, function factory( window, EventEmitter, eventie ) {



function noop() {}

function Unipointer() {}

// inherit EventEmitter
Unipointer.prototype = new EventEmitter();

Unipointer.prototype.bindStartEvent = function( elem ) {
  this._bindStartEvent( elem, true );
};

Unipointer.prototype.unbindStartEvent = function( elem ) {
  this._bindStartEvent( elem, false );
};

/**
 * works as unbinder, as you can ._bindStart( false ) to unbind
 * @param {Boolean} isBind - will unbind if falsey
 */
Unipointer.prototype._bindStartEvent = function( elem, isBind ) {
  // munge isBind, default to true
  isBind = isBind === undefined ? true : !!isBind;
  var bindMethod = isBind ? 'bind' : 'unbind';

  if ( window.navigator.pointerEnabled ) {
    // W3C Pointer Events, IE11. See https://coderwall.com/p/mfreca
    eventie[ bindMethod ]( elem, 'pointerdown', this );
  } else if ( window.navigator.msPointerEnabled ) {
    // IE10 Pointer Events
    eventie[ bindMethod ]( elem, 'MSPointerDown', this );
  } else {
    // listen for both, for devices like Chrome Pixel
    eventie[ bindMethod ]( elem, 'mousedown', this );
    eventie[ bindMethod ]( elem, 'touchstart', this );
  }
};

// trigger handler methods for events
Unipointer.prototype.handleEvent = function( event ) {
  var method = 'on' + event.type;
  if ( this[ method ] ) {
    this[ method ]( event );
  }
};

// returns the touch that we're keeping track of
Unipointer.prototype.getTouch = function( touches ) {
  for ( var i=0, len = touches.length; i < len; i++ ) {
    var touch = touches[i];
    if ( touch.identifier == this.pointerIdentifier ) {
      return touch;
    }
  }
};

// ----- start event ----- //

Unipointer.prototype.onmousedown = function( event ) {
  // dismiss clicks from right or middle buttons
  var button = event.button;
  if ( button && ( button !== 0 && button !== 1 ) ) {
    return;
  }
  this._pointerDown( event, event );
};

Unipointer.prototype.ontouchstart = function( event ) {
  this._pointerDown( event, event.changedTouches[0] );
};

Unipointer.prototype.onMSPointerDown =
Unipointer.prototype.onpointerdown = function( event ) {
  this._pointerDown( event, event );
};

/**
 * pointer start
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Unipointer.prototype._pointerDown = function( event, pointer ) {
  // dismiss other pointers
  if ( this.isPointerDown ) {
    return;
  }

  this.isPointerDown = true;
  // save pointer identifier to match up touch events
  this.pointerIdentifier = pointer.pointerId !== undefined ?
    // pointerId for pointer events, touch.indentifier for touch events
    pointer.pointerId : pointer.identifier;

  this.pointerDown( event, pointer );
};

Unipointer.prototype.pointerDown = function( event, pointer ) {
  this._bindPostStartEvents( event );
  this.emitEvent( 'pointerDown', [ event, pointer ] );
};

// hash of events to be bound after start event
var postStartEvents = {
  mousedown: [ 'mousemove', 'mouseup' ],
  touchstart: [ 'touchmove', 'touchend', 'touchcancel' ],
  pointerdown: [ 'pointermove', 'pointerup', 'pointercancel' ],
  MSPointerDown: [ 'MSPointerMove', 'MSPointerUp', 'MSPointerCancel' ]
};

Unipointer.prototype._bindPostStartEvents = function( event ) {
  if ( !event ) {
    return;
  }
  // get proper events to match start event
  var events = postStartEvents[ event.type ];
  // IE8 needs to be bound to document
  var node = event.preventDefault ? window : document;
  // bind events to node
  for ( var i=0, len = events.length; i < len; i++ ) {
    var evnt = events[i];
    eventie.bind( node, evnt, this );
  }
  // save these arguments
  this._boundPointerEvents = {
    events: events,
    node: node
  };
};

Unipointer.prototype._unbindPostStartEvents = function() {
  var args = this._boundPointerEvents;
  // IE8 can trigger dragEnd twice, check for _boundEvents
  if ( !args || !args.events ) {
    return;
  }

  for ( var i=0, len = args.events.length; i < len; i++ ) {
    var event = args.events[i];
    eventie.unbind( args.node, event, this );
  }
  delete this._boundPointerEvents;
};

// ----- move event ----- //

Unipointer.prototype.onmousemove = function( event ) {
  this._pointerMove( event, event );
};

Unipointer.prototype.onMSPointerMove =
Unipointer.prototype.onpointermove = function( event ) {
  if ( event.pointerId == this.pointerIdentifier ) {
    this._pointerMove( event, event );
  }
};

Unipointer.prototype.ontouchmove = function( event ) {
  var touch = this.getTouch( event.changedTouches );
  if ( touch ) {
    this._pointerMove( event, touch );
  }
};

/**
 * pointer move
 * @param {Event} event
 * @param {Event or Touch} pointer
 * @private
 */
Unipointer.prototype._pointerMove = function( event, pointer ) {
  this.pointerMove( event, pointer );
};

// public
Unipointer.prototype.pointerMove = function( event, pointer ) {
  this.emitEvent( 'pointerMove', [ event, pointer ] );
};

// ----- end event ----- //


Unipointer.prototype.onmouseup = function( event ) {
  this._pointerUp( event, event );
};

Unipointer.prototype.onMSPointerUp =
Unipointer.prototype.onpointerup = function( event ) {
  if ( event.pointerId == this.pointerIdentifier ) {
    this._pointerUp( event, event );
  }
};

Unipointer.prototype.ontouchend = function( event ) {
  var touch = this.getTouch( event.changedTouches );
  if ( touch ) {
    this._pointerUp( event, touch );
  }
};

/**
 * pointer up
 * @param {Event} event
 * @param {Event or Touch} pointer
 * @private
 */
Unipointer.prototype._pointerUp = function( event, pointer ) {
  this._pointerDone();
  this.pointerUp( event, pointer );
};

// public
Unipointer.prototype.pointerUp = function( event, pointer ) {
  this.emitEvent( 'pointerUp', [ event, pointer ] );
};

// ----- pointer done ----- //

// triggered on pointer up & pointer cancel
Unipointer.prototype._pointerDone = function() {
  // reset properties
  this.isPointerDown = false;
  delete this.pointerIdentifier;
  // remove events
  this._unbindPostStartEvents();
  this.pointerDone();
};

Unipointer.prototype.pointerDone = noop;

// ----- pointer cancel ----- //

Unipointer.prototype.onMSPointerCancel =
Unipointer.prototype.onpointercancel = function( event ) {
  if ( event.pointerId == this.pointerIdentifier ) {
    this._pointerCancel( event, event );
  }
};

Unipointer.prototype.ontouchcancel = function( event ) {
  var touch = this.getTouch( event.changedTouches );
  if ( touch ) {
    this._pointerCancel( event, touch );
  }
};

/**
 * pointer cancel
 * @param {Event} event
 * @param {Event or Touch} pointer
 * @private
 */
Unipointer.prototype._pointerCancel = function( event, pointer ) {
  this._pointerDone();
  this.pointerCancel( event, pointer );
};

// public
Unipointer.prototype.pointerCancel = function( event, pointer ) {
  this.emitEvent( 'pointerCancel', [ event, pointer ] );
};

// -----  ----- //

// utility function for getting x/y cooridinates from event, because IE8
Unipointer.getPointerPoint = function( pointer ) {
  return {
    x: pointer.pageX !== undefined ? pointer.pageX : pointer.clientX,
    y: pointer.pageY !== undefined ? pointer.pageY : pointer.clientY
  };
};

// -----  ----- //

return Unipointer;

}));

/*!
 * Unidragger v1.1.0
 * Draggable base class
 * MIT license
 */

/*jshint browser: true, unused: true, undef: true, strict: true */

( function( window, factory ) {
  /*global define: false, module: false, require: false */
  
  // universal module definition

  if ( typeof define == 'function' && define.amd ) {
    // AMD
    define( 'unidragger/unidragger',[
      'eventie/eventie',
      'unipointer/unipointer'
    ], function( eventie, Unipointer ) {
      return factory( window, eventie, Unipointer );
    });
  } else if ( typeof exports == 'object' ) {
    // CommonJS
    module.exports = factory(
      window,
      require('eventie'),
      require('unipointer')
    );
  } else {
    // browser global
    window.Unidragger = factory(
      window,
      window.eventie,
      window.Unipointer
    );
  }

}( window, function factory( window, eventie, Unipointer ) {



// -----  ----- //

function noop() {}

// handle IE8 prevent default
function preventDefaultEvent( event ) {
  if ( event.preventDefault ) {
    event.preventDefault();
  } else {
    event.returnValue = false;
  }
}

function getParentLink( elem ) {
  while ( elem != document.body ) {
    elem = elem.parentNode;
    if ( elem.nodeName == 'A' ) {
      return elem;
    }
  }
}

// -------------------------- Unidragger -------------------------- //

function Unidragger() {}

// inherit Unipointer & EventEmitter
Unidragger.prototype = new Unipointer();

// ----- bind start ----- //

Unidragger.prototype.bindHandles = function() {
  this._bindHandles( true );
};

Unidragger.prototype.unbindHandles = function() {
  this._bindHandles( false );
};

var navigator = window.navigator;
/**
 * works as unbinder, as you can .bindHandles( false ) to unbind
 * @param {Boolean} isBind - will unbind if falsey
 */
Unidragger.prototype._bindHandles = function( isBind ) {
  // munge isBind, default to true
  isBind = isBind === undefined ? true : !!isBind;
  // extra bind logic
  var binderExtra;
  if ( navigator.pointerEnabled ) {
    binderExtra = function( handle ) {
      // disable scrolling on the element
      handle.style.touchAction = isBind ? 'none' : '';
    };
  } else if ( navigator.msPointerEnabled ) {
    binderExtra = function( handle ) {
      // disable scrolling on the element
      handle.style.msTouchAction = isBind ? 'none' : '';
    };
  } else {
    binderExtra = function() {
      // TODO re-enable img.ondragstart when unbinding
      if ( isBind ) {
        disableImgOndragstart( handle );
      }
    };
  }
  // bind each handle
  var bindMethod = isBind ? 'bind' : 'unbind';
  for ( var i=0, len = this.handles.length; i < len; i++ ) {
    var handle = this.handles[i];
    this._bindStartEvent( handle, isBind );
    binderExtra( handle );
    eventie[ bindMethod ]( handle, 'click', this );
  }
};

// remove default dragging interaction on all images in IE8
// IE8 does its own drag thing on images, which messes stuff up

function noDragStart() {
  return false;
}

// TODO replace this with a IE8 test
var isIE8 = 'attachEvent' in document.documentElement;

// IE8 only
var disableImgOndragstart = !isIE8 ? noop : function( handle ) {

  if ( handle.nodeName == 'IMG' ) {
    handle.ondragstart = noDragStart;
  }

  var images = handle.querySelectorAll('img');
  for ( var i=0, len = images.length; i < len; i++ ) {
    var img = images[i];
    img.ondragstart = noDragStart;
  }
};

// ----- start event ----- //

var allowTouchstartNodes = Unidragger.allowTouchstartNodes = {
  INPUT: true,
  A: true,
  BUTTON: true,
  SELECT: true
};

/**
 * pointer start
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Unidragger.prototype.pointerDown = function( event, pointer ) {
  this._dragPointerDown( event, pointer );
  // kludge to blur focused inputs in dragger
  var focused = document.activeElement;
  if ( focused && focused.blur ) {
    focused.blur();
  }
  // bind move and end events
  this._bindPostStartEvents( event );
  this.emitEvent( 'pointerDown', [ event, pointer ] );
};

// base pointer down logic
Unidragger.prototype._dragPointerDown = function( event, pointer ) {
  // track to see when dragging starts
  this.pointerDownPoint = Unipointer.getPointerPoint( pointer );

  var targetNodeName = event.target.nodeName;
  // HACK iOS, allow clicks on buttons, inputs, and links, or children of links
  var isTouchstartNode = event.type == 'touchstart' &&
    ( allowTouchstartNodes[ targetNodeName ] || getParentLink( event.target ) );
  // do not prevent default on touchstart nodes or <select>
  if ( !isTouchstartNode && targetNodeName != 'SELECT' ) {
    preventDefaultEvent( event );
  }
};

// ----- move event ----- //

/**
 * drag move
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Unidragger.prototype.pointerMove = function( event, pointer ) {
  var moveVector = this._dragPointerMove( event, pointer );
  this.emitEvent( 'pointerMove', [ event, pointer, moveVector ] );
  this._dragMove( event, pointer, moveVector );
};

// base pointer move logic
Unidragger.prototype._dragPointerMove = function( event, pointer ) {
  var movePoint = Unipointer.getPointerPoint( pointer );
  var moveVector = {
    x: movePoint.x - this.pointerDownPoint.x,
    y: movePoint.y - this.pointerDownPoint.y
  };
  // start drag if pointer has moved far enough to start drag
  if ( !this.isDragging && this.hasDragStarted( moveVector ) ) {
    this._dragStart( event, pointer );
  }
  return moveVector;
};

// condition if pointer has moved far enough to start drag
Unidragger.prototype.hasDragStarted = function( moveVector ) {
  return Math.abs( moveVector.x ) > 3 || Math.abs( moveVector.y ) > 3;
};


// ----- end event ----- //

/**
 * pointer up
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Unidragger.prototype.pointerUp = function( event, pointer ) {
  this.emitEvent( 'pointerUp', [ event, pointer ] );
  this._dragPointerUp( event, pointer );
};

Unidragger.prototype._dragPointerUp = function( event, pointer ) {
  if ( this.isDragging ) {
    this._dragEnd( event, pointer );
  } else {
    // pointer didn't move enough for drag to start
    this._staticClick( event, pointer );
  }
};

// -------------------------- drag -------------------------- //

// dragStart
Unidragger.prototype._dragStart = function( event, pointer ) {
  this.isDragging = true;
  this.dragStartPoint = Unidragger.getPointerPoint( pointer );
  // prevent clicks
  this.isPreventingClicks = true;

  this.dragStart( event, pointer );
};

Unidragger.prototype.dragStart = function( event, pointer ) {
  this.emitEvent( 'dragStart', [ event, pointer ] );
};

// dragMove
Unidragger.prototype._dragMove = function( event, pointer, moveVector ) {
  // do not drag if not dragging yet
  if ( !this.isDragging ) {
    return;
  }

  this.dragMove( event, pointer, moveVector );
};

Unidragger.prototype.dragMove = function( event, pointer, moveVector ) {
  this.emitEvent( 'dragMove', [ event, pointer, moveVector ] );
};

// dragEnd
Unidragger.prototype._dragEnd = function( event, pointer ) {
  // set flags
  this.isDragging = false;
  // re-enable clicking async
  var _this = this;
  setTimeout( function() {
    delete _this.isPreventingClicks;
  });

  this.dragEnd( event, pointer );
};

Unidragger.prototype.dragEnd = function( event, pointer ) {
  this.emitEvent( 'dragEnd', [ event, pointer ] );
};

// ----- onclick ----- //

// handle all clicks and prevent clicks when dragging
Unidragger.prototype.onclick = function( event ) {
  if ( this.isPreventingClicks ) {
    preventDefaultEvent( event );
  }
};

// ----- staticClick ----- //

// triggered after pointer down & up with no/tiny movement
Unidragger.prototype._staticClick = function( event, pointer ) {
  // allow click in text input
  if ( event.target.nodeName == 'INPUT' && event.target.type == 'text' ) {
    event.target.focus();
  }
  this.staticClick( event, pointer );
};

Unidragger.prototype.staticClick = function( event, pointer ) {
  this.emitEvent( 'staticClick', [ event, pointer ] );
};

// -----  ----- //

Unidragger.getPointerPoint = function( pointer ) {
  return {
    x: pointer.pageX !== undefined ? pointer.pageX : pointer.clientX,
    y: pointer.pageY !== undefined ? pointer.pageY : pointer.clientY
  };
};

// -----  ----- //

Unidragger.getPointerPoint = Unipointer.getPointerPoint;

return Unidragger;

}));

/*!
 * Draggabilly v1.2.4
 * Make that shiz draggable
 * http://draggabilly.desandro.com
 * MIT license
 */

( function( window, factory ) {
  

  if ( typeof define == 'function' && define.amd ) {
    // AMD
    // Note: fixed by andy-armstrong to include a name for the definition
    // so that this works when optimized using r.js. This is only an issue
    // in Studio, as the LMS uses a namespaced version of RequireJS so
    // this clause isn't reached.
    // See http://requirejs.org/docs/errors.html#mismatch
    define(
      'draggabilly',
      [
        'classie/classie',
        'get-style-property/get-style-property',
        'get-size/get-size',
        'unidragger/unidragger'
      ],
      function( classie, getStyleProperty, getSize, Unidragger ) {
        return factory( window, classie, getStyleProperty, getSize, Unidragger );
      });
  } else if ( typeof exports == 'object' ) {
    // CommonJS
    module.exports = factory(
      window,
      require('desandro-classie'),
      require('desandro-get-style-property'),
      require('get-size'),
      require('unidragger')
    );
  } else {
    // browser global
    window.Draggabilly = factory(
      window,
      window.classie,
      window.getStyleProperty,
      window.getSize,
      window.Unidragger
    );
  }

}( window, function factory( window, classie, getStyleProperty, getSize, Unidragger ) {



// vars
var document = window.document;

function noop() {}

// -------------------------- helpers -------------------------- //

// extend objects
function extend( a, b ) {
  for ( var prop in b ) {
    a[ prop ] = b[ prop ];
  }
  return a;
}

// ----- get style ----- //

var defView = document.defaultView;

var getStyle = defView && defView.getComputedStyle ?
  function( elem ) {
    return defView.getComputedStyle( elem, null );
  } :
  function( elem ) {
    return elem.currentStyle;
  };


// http://stackoverflow.com/a/384380/182183
var isElement = ( typeof HTMLElement == 'object' ) ?
  function isElementDOM2( obj ) {
    return obj instanceof HTMLElement;
  } :
  function isElementQuirky( obj ) {
    return obj && typeof obj == 'object' &&
      obj.nodeType == 1 && typeof obj.nodeName == 'string';
  };

// -------------------------- requestAnimationFrame -------------------------- //

// https://gist.github.com/1866474

var lastTime = 0;
var prefixes = 'webkit moz ms o'.split(' ');
// get unprefixed rAF and cAF, if present
var requestAnimationFrame = window.requestAnimationFrame;
var cancelAnimationFrame = window.cancelAnimationFrame;
// loop through vendor prefixes and get prefixed rAF and cAF
var prefix;
for( var i = 0; i < prefixes.length; i++ ) {
  if ( requestAnimationFrame && cancelAnimationFrame ) {
    break;
  }
  prefix = prefixes[i];
  requestAnimationFrame = requestAnimationFrame || window[ prefix + 'RequestAnimationFrame' ];
  cancelAnimationFrame  = cancelAnimationFrame  || window[ prefix + 'CancelAnimationFrame' ] ||
                            window[ prefix + 'CancelRequestAnimationFrame' ];
}

// fallback to setTimeout and clearTimeout if either request/cancel is not supported
if ( !requestAnimationFrame || !cancelAnimationFrame )  {
  requestAnimationFrame = function( callback ) {
    var currTime = new Date().getTime();
    var timeToCall = Math.max( 0, 16 - ( currTime - lastTime ) );
    var id = window.setTimeout( function() {
      callback( currTime + timeToCall );
    }, timeToCall );
    lastTime = currTime + timeToCall;
    return id;
  };

  cancelAnimationFrame = function( id ) {
    window.clearTimeout( id );
  };
}

// -------------------------- support -------------------------- //

var transformProperty = getStyleProperty('transform');
// TODO fix quick & dirty check for 3D support
var is3d = !!getStyleProperty('perspective');

var jQuery = window.jQuery;

// --------------------------  -------------------------- //

function Draggabilly( element, options ) {
  // querySelector if string
  this.element = typeof element == 'string' ?
    document.querySelector( element ) : element;

  if ( jQuery ) {
    this.$element = jQuery( this.element );
  }

  // options
  this.options = extend( {}, this.constructor.defaults );
  this.option( options );

  this._create();
}

// inherit Unidragger methods
extend( Draggabilly.prototype, Unidragger.prototype );

Draggabilly.defaults = {
};

/**
 * set options
 * @param {Object} opts
 */
Draggabilly.prototype.option = function( opts ) {
  extend( this.options, opts );
};

Draggabilly.prototype._create = function() {

  // properties
  this.position = {};
  this._getPosition();

  this.startPoint = { x: 0, y: 0 };
  this.dragPoint = { x: 0, y: 0 };

  this.startPosition = extend( {}, this.position );

  // set relative positioning
  var style = getStyle( this.element );
  if ( style.position != 'relative' && style.position != 'absolute' ) {
    this.element.style.position = 'relative';
  }

  this.enable();
  this.setHandles();

};

/**
 * set this.handles and bind start events to 'em
 */
Draggabilly.prototype.setHandles = function() {
  this.handles = this.options.handle ?
    this.element.querySelectorAll( this.options.handle ) : [ this.element ];

  this.bindHandles();
};

/**
 * emits events via eventEmitter and jQuery events
 * @param {String} type - name of event
 * @param {Event} event - original event
 * @param {Array} args - extra arguments
 */
Draggabilly.prototype.dispatchEvent = function( type, event, args ) {
  var emitArgs = [ event ].concat( args );
  this.emitEvent( type, emitArgs );
  var jQuery = window.jQuery;
  // trigger jQuery event
  if ( jQuery && this.$element ) {
    if ( event ) {
      // create jQuery event
      var $event = jQuery.Event( event );
      $event.type = type;
      this.$element.trigger( $event, args );
    } else {
      // just trigger with type if no event available
      this.$element.trigger( type, args );
    }
  }
};

// -------------------------- position -------------------------- //

// get left/top position from style
Draggabilly.prototype._getPosition = function() {
  // properties
  var style = getStyle( this.element );

  var x = parseInt( style.left, 10 );
  var y = parseInt( style.top, 10 );

  // clean up 'auto' or other non-integer values
  this.position.x = isNaN( x ) ? 0 : x;
  this.position.y = isNaN( y ) ? 0 : y;

  this._addTransformPosition( style );
};

// add transform: translate( x, y ) to position
Draggabilly.prototype._addTransformPosition = function( style ) {
  if ( !transformProperty ) {
    return;
  }
  var transform = style[ transformProperty ];
  // bail out if value is 'none'
  if ( transform.indexOf('matrix') !== 0 ) {
    return;
  }
  // split matrix(1, 0, 0, 1, x, y)
  var matrixValues = transform.split(',');
  // translate X value is in 12th or 4th position
  var xIndex = transform.indexOf('matrix3d') === 0 ? 12 : 4;
  var translateX = parseInt( matrixValues[ xIndex ], 10 );
  // translate Y value is in 13th or 5th position
  var translateY = parseInt( matrixValues[ xIndex + 1 ], 10 );
  this.position.x += translateX;
  this.position.y += translateY;
};

// -------------------------- events -------------------------- //

/**
 * pointer start
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Draggabilly.prototype.pointerDown = function( event, pointer ) {
  this._dragPointerDown( event, pointer );
  // kludge to blur focused inputs in dragger
  var focused = document.activeElement;
  if ( focused && focused.blur ) {
    focused.blur();
  }
  // bind move and end events
  this._bindPostStartEvents( event );
  classie.add( this.element, 'is-pointer-down' );
  this.dispatchEvent( 'pointerDown', event, [ pointer ] );
};

/**
 * drag move
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Draggabilly.prototype.pointerMove = function( event, pointer ) {
  var moveVector = this._dragPointerMove( event, pointer );
  this.dispatchEvent( 'pointerMove', event, [ pointer, moveVector ] );
  this._dragMove( event, pointer, moveVector );
};

/**
 * drag start
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Draggabilly.prototype.dragStart = function( event, pointer ) {
  if ( !this.isEnabled ) {
    return;
  }
  this._getPosition();
  this.measureContainment();
  // position _when_ drag began
  this.startPosition.x = this.position.x;
  this.startPosition.y = this.position.y;
  // reset left/top style
  this.setLeftTop();

  this.dragPoint.x = 0;
  this.dragPoint.y = 0;

  // reset isDragging flag
  this.isDragging = true;
  classie.add( this.element, 'is-dragging' );
  this.dispatchEvent( 'dragStart', event, [ pointer ] );
  // start animation
  this.animate();
};

Draggabilly.prototype.measureContainment = function() {
  var containment = this.options.containment;
  if ( !containment ) {
    return;
  }

  this.size = getSize( this.element );
  var elemRect = this.element.getBoundingClientRect();

  // use element if element
  var container = isElement( containment ) ? containment :
    // fallback to querySelector if string
    typeof containment == 'string' ? document.querySelector( containment ) :
    // otherwise just `true`, use the parent
    this.element.parentNode;

  this.containerSize = getSize( container );
  var containerRect = container.getBoundingClientRect();

  this.relativeStartPosition = {
    x: elemRect.left - containerRect.left,
    y: elemRect.top  - containerRect.top
  };
};

// ----- move event ----- //

/**
 * drag move
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Draggabilly.prototype.dragMove = function( event, pointer, moveVector ) {
  if ( !this.isEnabled ) {
    return;
  }
  var dragX = moveVector.x;
  var dragY = moveVector.y;

  var grid = this.options.grid;
  var gridX = grid && grid[0];
  var gridY = grid && grid[1];

  dragX = applyGrid( dragX, gridX );
  dragY = applyGrid( dragY, gridY );

  dragX = this.containDrag( 'x', dragX, gridX );
  dragY = this.containDrag( 'y', dragY, gridY );

  // constrain to axis
  dragX = this.options.axis == 'y' ? 0 : dragX;
  dragY = this.options.axis == 'x' ? 0 : dragY;

  this.position.x = this.startPosition.x + dragX;
  this.position.y = this.startPosition.y + dragY;
  // set dragPoint properties
  this.dragPoint.x = dragX;
  this.dragPoint.y = dragY;

  this.dispatchEvent( 'dragMove', event, [ pointer, moveVector ] );
};

function applyGrid( value, grid, method ) {
  method = method || 'round';
  return grid ? Math[ method ]( value / grid ) * grid : value;
}

Draggabilly.prototype.containDrag = function( axis, drag, grid ) {
  if ( !this.options.containment ) {
    return drag;
  }
  var measure = axis == 'x' ? 'width' : 'height';

  var rel = this.relativeStartPosition[ axis ];
  var min = applyGrid( -rel, grid, 'ceil' );
  var max = this.containerSize[ measure ] - rel - this.size[ measure ];
  max = applyGrid( max, grid, 'floor' );
  return  Math.min( max, Math.max( min, drag ) );
};

// ----- end event ----- //

/**
 * pointer up
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Draggabilly.prototype.pointerUp = function( event, pointer ) {
  classie.remove( this.element, 'is-pointer-down' );
  this.dispatchEvent( 'pointerUp', event, [ pointer ] );
  this._dragPointerUp( event, pointer );
};

/**
 * drag end
 * @param {Event} event
 * @param {Event or Touch} pointer
 */
Draggabilly.prototype.dragEnd = function( event, pointer ) {
  if ( !this.isEnabled ) {
    return;
  }
  this.isDragging = false;
  // use top left position when complete
  if ( transformProperty ) {
    this.element.style[ transformProperty ] = '';
    this.setLeftTop();
  }
  classie.remove( this.element, 'is-dragging' );
  this.dispatchEvent( 'dragEnd', event, [ pointer ] );
};

// -------------------------- animation -------------------------- //

Draggabilly.prototype.animate = function() {
  // only render and animate if dragging
  if ( !this.isDragging ) {
    return;
  }

  this.positionDrag();

  var _this = this;
  requestAnimationFrame( function animateFrame() {
    _this.animate();
  });

};

// transform translate function
var translate = is3d ?
  function( x, y ) {
    return 'translate3d( ' + x + 'px, ' + y + 'px, 0)';
  } :
  function( x, y ) {
    return 'translate( ' + x + 'px, ' + y + 'px)';
  };

// left/top positioning
Draggabilly.prototype.setLeftTop = function() {
  this.element.style.left = this.position.x + 'px';
  this.element.style.top  = this.position.y + 'px';
};

Draggabilly.prototype.positionDrag = transformProperty ?
  function() {
    // position with transform
    this.element.style[ transformProperty ] = translate( this.dragPoint.x, this.dragPoint.y );
  } : Draggabilly.prototype.setLeftTop;

// ----- staticClick ----- //

Draggabilly.prototype.staticClick = function( event, pointer ) {
  this.dispatchEvent( 'staticClick', event, [ pointer ] );
};

// ----- methods ----- //

Draggabilly.prototype.enable = function() {
  this.isEnabled = true;
};

Draggabilly.prototype.disable = function() {
  this.isEnabled = false;
  if ( this.isDragging ) {
    this.dragEnd();
  }
};

Draggabilly.prototype.destroy = function() {
  this.disable();
  // reset styles
  if ( transformProperty ) {
    this.element.style[ transformProperty ] = '';
  }
  this.element.style.left = '';
  this.element.style.top = '';
  this.element.style.position = '';
  // unbind handles
  this.unbindHandles();
  // remove jQuery data
  if ( this.$element ) {
    this.$element.removeData('draggabilly');
  }
};

// ----- jQuery bridget ----- //

// required for jQuery bridget
Draggabilly.prototype._init = noop;

if ( jQuery && jQuery.bridget ) {
  jQuery.bridget( 'draggabilly', Draggabilly );
}

// -----  ----- //

return Draggabilly;

}));