The Tor Browser: accessible/src/jsat/Gestures.jsm@141e0f1194b1 (annotated)

accessible/src/jsat/Gestures.jsm@141e0f1194b1 (annotated)

accessible/src/jsat/Gestures.jsm

Wed, 31 Dec 2014 07:16:47 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:16:47 +0100
branch: TOR_BUG_9701
changeset 3: 141e0f1194b1
permissions: -rw-r--r--

Revert simplistic fix pending revisit of Mozilla integration attempt.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 /* global Components, GestureSettings, XPCOMUtils, Utils, Promise, Logger */
 /* exported GestureSettings, GestureTracker */
 /******************************************************************************
   All gestures have the following pathways when being resolved(v)/rejected(x):
                Tap -> DoubleTap        (v)
                    -> Dwell            (x)
                    -> Swipe            (x)
         AndroidTap -> TripleTap        (v)
                    -> TapHold          (x)
                    -> Swipe            (x)
          DoubleTap -> TripleTap        (v)
                    -> TapHold          (x)
                    -> Explore          (x)
          TripleTap -> DoubleTapHold    (x)
                    -> Explore          (x)
              Dwell -> DwellEnd         (v)
              Swipe -> Explore          (x)
            TapHold -> TapHoldEnd       (v)
      DoubleTapHold -> DoubleTapHoldEnd (v)
           DwellEnd -> Explore          (x)
         TapHoldEnd -> Explore          (x)
   DoubleTapHoldEnd -> Explore          (x)
         ExploreEnd -> Explore          (x)
            Explore -> ExploreEnd       (v)
 ******************************************************************************/
 'use strict';
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 this.EXPORTED_SYMBOLS = ['GestureSettings', 'GestureTracker']; // jshint ignore:line
 Cu.import('resource://gre/modules/XPCOMUtils.jsm');
 XPCOMUtils.defineLazyModuleGetter(this, 'Utils', // jshint ignore:line
   'resource://gre/modules/accessibility/Utils.jsm');
 XPCOMUtils.defineLazyModuleGetter(this, 'Logger', // jshint ignore:line
   'resource://gre/modules/accessibility/Utils.jsm');
 XPCOMUtils.defineLazyModuleGetter(this, 'setTimeout', // jshint ignore:line
   'resource://gre/modules/Timer.jsm');
 XPCOMUtils.defineLazyModuleGetter(this, 'clearTimeout', // jshint ignore:line
   'resource://gre/modules/Timer.jsm');
 XPCOMUtils.defineLazyModuleGetter(this, 'Promise', // jshint ignore:line
   'resource://gre/modules/Promise.jsm');
 // Maximum amount of time allowed for a gesture to be considered a multitouch.
 const MAX_MULTITOUCH = 250;
 // Minimal swipe distance in inches
 const SWIPE_MIN_DISTANCE = 0.4;
 // Maximum distance the pointer could move during a tap in inches
 const TAP_MAX_RADIUS = 0.2;
 // Directness coefficient. It is based on the maximum 15 degree angle between
 // consequent pointer move lines.
 const DIRECTNESS_COEFF = 1.44;
 // An android flag.
 const IS_ANDROID = Utils.MozBuildApp === 'mobile/android' &&
   Utils.AndroidSdkVersion >= 14;
 // A single pointer down/up sequence periodically precedes the tripple swipe
 // gesture on Android. This delay acounts for that.
 const ANDROID_TRIPLE_SWIPE_DELAY = 50;
 // The virtual touch ID generated by a mouse event.
 const MOUSE_ID = 'mouse';
 /**
  * A point object containing distance travelled data.
  * @param {Object} aPoint A point object that looks like: {
  *   x: x coordinate in pixels,
  *   y: y coordinate in pixels
  * }
  */
 function Point(aPoint) {
   this.startX = this.x = aPoint.x;
   this.startY = this.y = aPoint.y;
   this.distanceTraveled = 0;
   this.totalDistanceTraveled = 0;
 }
 Point.prototype = {
   /**
    * Update the current point coordiates.
    * @param  {Object} aPoint A new point coordinates.
    */
   update: function Point_update(aPoint) {
     let lastX = this.x;
     let lastY = this.y;
     this.x = aPoint.x;
     this.y = aPoint.y;
     this.distanceTraveled = this.getDistanceToCoord(lastX, lastY);
     this.totalDistanceTraveled += this.distanceTraveled;
   },
   reset: function Point_reset() {
     this.distanceTraveled = 0;
     this.totalDistanceTraveled = 0;
   },
   /**
    * Get distance between the current point coordinates and the given ones.
    * @param  {Number} aX A pixel value for the x coordinate.
    * @param  {Number} aY A pixel value for the y coordinate.
    * @return {Number} A distance between point's current and the given
    * coordinates.
    */
   getDistanceToCoord: function Point_getDistanceToCoord(aX, aY) {
     return Math.hypot(this.x - aX, this.y - aY);
   },
   /**
    * Get the direct distance travelled by the point so far.
    */
   get directDistanceTraveled() {
     return this.getDistanceToCoord(this.startX, this.startY);
   }
 };
 /**
  * An externally accessible collection of settings used in gesture resolition.
  * @type {Object}
  */
 this.GestureSettings = { // jshint ignore:line
   /**
    * Maximum duration of swipe
    * @type {Number}
    */
   swipeMaxDuration: 400,
   /**
    * Maximum consecutive pointer event timeout.
    * @type {Number}
    */
   maxConsecutiveGestureDelay: 400,
   /**
    * Delay before tap turns into dwell
    * @type {Number}
    */
   dwellThreshold: 500,
   /**
    * Minimum distance that needs to be travelled for the pointer move to be
    * fired.
    * @type {Number}
    */
   travelThreshold: 0.025
 };
 /**
  * An interface that handles the pointer events and calculates the appropriate
  * gestures.
  * @type {Object}
  */
 this.GestureTracker = { // jshint ignore:line
   /**
    * Reset GestureTracker to its initial state.
    * @return {[type]} [description]
    */
   reset: function GestureTracker_reset() {
     if (this.current) {
       this.current.clearTimer();
     }
     delete this.current;
   },
   /**
    * Create a new gesture object and attach resolution handler to it as well as
    * handle the incoming pointer event.
    * @param  {Object} aDetail A new pointer event detail.
    * @param  {Number} aTimeStamp A new pointer event timeStamp.
    * @param  {Function} aGesture A gesture constructor (default: Tap).
    */
   _init: function GestureTracker__init(aDetail, aTimeStamp, aGesture = Tap) {
     // Only create a new gesture on |pointerdown| event.
     if (aDetail.type !== 'pointerdown') {
       return;
     }
     let points = aDetail.points;
     let GestureConstructor = aGesture;
     if (IS_ANDROID && GestureConstructor === Tap && points.length === 1 &&
       points[0].identifier !== MOUSE_ID) {
       // Handle Android events when EBT is enabled. Two finger gestures are
       // translated to one.
       GestureConstructor = AndroidTap;
     }
     this._create(GestureConstructor);
     this._update(aDetail, aTimeStamp);
   },
   /**
    * Handle the incoming pointer event with the existing gesture object(if
    * present) or with the newly created one.
    * @param  {Object} aDetail A new pointer event detail.
    * @param  {Number} aTimeStamp A new pointer event timeStamp.
    */
   handle: function GestureTracker_handle(aDetail, aTimeStamp) {
     Logger.debug(() => {
       return ['Pointer event', aDetail.type, 'at:', aTimeStamp,
         JSON.stringify(aDetail.points)];
     });
     this[this.current ? '_update' : '_init'](aDetail, aTimeStamp);
   },
   /**
    * Create a new gesture object and attach resolution handler to it.
    * @param  {Function} aGesture A gesture constructor.
    * @param  {Number} aTimeStamp An original pointer event timeStamp.
    * @param  {Array} aPoints All changed points associated with the new pointer
    * event.
    * @param {?String} aLastEvent Last pointer event type.
    */
   _create: function GestureTracker__create(aGesture, aTimeStamp, aPoints, aLastEvent) {
     this.current = new aGesture(aTimeStamp, aPoints, aLastEvent); /* A constructor name should start with an uppercase letter. */ // jshint ignore:line
     this.current.then(this._onFulfill.bind(this));
   },
   /**
    * Handle the incoming pointer event with the existing gesture object.
    * @param  {Object} aDetail A new pointer event detail.
    * @param  {Number} aTimeStamp A new pointer event timeStamp.
    */
   _update: function GestureTracker_update(aDetail, aTimeStamp) {
     this.current[aDetail.type](aDetail.points, aTimeStamp);
   },
   /**
    * A resolution handler function for the current gesture promise.
    * @param  {Object} aResult A resolution payload with the relevant gesture id
    * and an optional new gesture contructor.
    */
   _onFulfill: function GestureTracker__onFulfill(aResult) {
     let {id, gestureType} = aResult;
     let current = this.current;
     // Do nothing if there's no existing gesture or there's already a newer
     // gesture.
     if (!current || current.id !== id) {
       return;
     }
     // Only create a gesture if we got a constructor.
     if (gestureType) {
       this._create(gestureType, current.startTime, current.points,
         current.lastEvent);
     } else {
       delete this.current;
     }
   }
 };
 /**
  * Compile a mozAccessFuGesture detail structure.
  * @param  {String} aType A gesture type.
  * @param  {Object} aPoints Gesture's points.
  * @param  {String} xKey A default key for the x coordinate. Default is
  * 'startX'.
  * @param  {String} yKey A default key for the y coordinate. Default is
  * 'startY'.
  * @return {Object} a mozAccessFuGesture detail structure.
  */
 function compileDetail(aType, aPoints, keyMap = {x: 'startX', y: 'startY'}) {
   let touches = [];
   let maxDeltaX = 0;
   let maxDeltaY = 0;
   for (let identifier in aPoints) {
     let point = aPoints[identifier];
     let touch = {};
     for (let key in keyMap) {
       touch[key] = point[keyMap[key]];
     }
     touches.push(touch);
     let deltaX = point.x - point.startX;
     let deltaY = point.y - point.startY;
     // Determine the maximum x and y travel intervals.
     if (Math.abs(maxDeltaX) < Math.abs(deltaX)) {
       maxDeltaX = deltaX;
     }
     if (Math.abs(maxDeltaY) < Math.abs(deltaY)) {
       maxDeltaY = deltaY;
     }
     // Since the gesture is resolving, reset the points' distance information
     // since they are passed to the next potential gesture.
     point.reset();
   }
   return {
     type: aType,
     touches: touches,
     deltaX: maxDeltaX,
     deltaY: maxDeltaY
   };
 }
 /**
  * A general gesture object.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * Default is an empty object.
  * @param {?String} aLastEvent Last pointer event type.
  */
 function Gesture(aTimeStamp, aPoints = {}, aLastEvent = undefined) {
   this.startTime = Date.now();
   Logger.debug('Creating', this.id, 'gesture.');
   this.points = aPoints;
   this.lastEvent = aLastEvent;
   this._deferred = Promise.defer();
   // Call this._handleResolve or this._handleReject when the promise is
   // fulfilled with either resolve or reject.
   this.promise = this._deferred.promise.then(this._handleResolve.bind(this),
     this._handleReject.bind(this));
   this.startTimer(aTimeStamp);
 }
 Gesture.prototype = {
   /**
    * Get the gesture timeout delay.
    * @return {Number}
    */
   _getDelay: function Gesture__getDelay() {
     // If nothing happens withing the
     // GestureSettings.maxConsecutiveGestureDelay, we should not wait for any
     // more pointer events and consider them the part of the same gesture -
     // reject this gesture promise.
     return GestureSettings.maxConsecutiveGestureDelay;
   },
   /**
    * Clear the existing timer.
    */
   clearTimer: function Gesture_clearTimer() {
     clearTimeout(this._timer);
     delete this._timer;
   },
   /**
    * Start the timer for gesture timeout.
    * @param {Number} aTimeStamp An original pointer event's timeStamp that
    * started the gesture resolution sequence.
    */
   startTimer: function Gesture_startTimer(aTimeStamp) {
     this.clearTimer();
     let delay = this._getDelay(aTimeStamp);
     let handler = () => {
       delete this._timer;
       if (!this._inProgress) {
         this._deferred.reject();
       } else if (this._rejectToOnWait) {
         this._deferred.reject(this._rejectToOnWait);
       }
     };
     if (delay <= 0) {
       handler();
     } else {
       this._timer = setTimeout(handler, delay);
     }
   },
   /**
    * Add a gesture promise resolution callback.
    * @param  {Function} aCallback
    */
   then: function Gesture_then(aCallback) {
     this.promise.then(aCallback);
   },
   /**
    * Update gesture's points. Test the points set with the optional gesture test
    * function.
    * @param  {Array} aPoints An array with the changed points from the new
    * pointer event.
    * @param {String} aType Pointer event type.
    * @param  {Boolean} aCanCreate A flag that enables including the new points.
    * Default is false.
    * @param  {Boolean} aNeedComplete A flag that indicates that the gesture is
    * completing. Default is false.
    * @return {Boolean} Indicates whether the gesture can be complete (it is
    * set to true iff the aNeedComplete is true and there was a change to at
    * least one point that belongs to the gesture).
    */
   _update: function Gesture__update(aPoints, aType, aCanCreate = false, aNeedComplete = false) {
     let complete;
     let lastEvent;
     for (let point of aPoints) {
       let identifier = point.identifier;
       let gesturePoint = this.points[identifier];
       if (gesturePoint) {
         gesturePoint.update(point);
         if (aNeedComplete) {
           // Since the gesture is completing and at least one of the gesture
           // points is updated, set the return value to true.
           complete = true;
         }
         lastEvent = lastEvent || aType;
       } else if (aCanCreate) {
         // Only create a new point if aCanCreate is true.
         this.points[identifier] =
           new Point(point);
         lastEvent = lastEvent || aType;
       }
     }
     this.lastEvent = lastEvent || this.lastEvent;
     // If test function is defined test the points.
     if (this.test) {
       this.test(complete);
     }
     return complete;
   },
   /**
    * Emit a mozAccessFuGesture (when the gesture is resolved).
    * @param  {Object} aDetail a compiled mozAccessFuGesture detail structure.
    */
   _emit: function Gesture__emit(aDetail) {
     let evt = new Utils.win.CustomEvent('mozAccessFuGesture', {
       bubbles: true,
       cancelable: true,
       detail: aDetail
     });
     Utils.win.dispatchEvent(evt);
   },
   /**
    * Handle the pointer down event.
    * @param  {Array} aPoints A new pointer down points.
    * @param  {Number} aTimeStamp A new pointer down timeStamp.
    */
   pointerdown: function Gesture_pointerdown(aPoints, aTimeStamp) {
     this._inProgress = true;
     this._update(aPoints, 'pointerdown',
       aTimeStamp - this.startTime < MAX_MULTITOUCH);
   },
   /**
    * Handle the pointer move event.
    * @param  {Array} aPoints A new pointer move points.
    */
   pointermove: function Gesture_pointermove(aPoints) {
     this._update(aPoints, 'pointermove');
   },
   /**
    * Handle the pointer up event.
    * @param  {Array} aPoints A new pointer up points.
    */
   pointerup: function Gesture_pointerup(aPoints) {
     let complete = this._update(aPoints, 'pointerup', false, true);
     if (complete) {
       this._deferred.resolve();
     }
   },
   /**
    * A subsequent gesture constructor to resolve the current one to. E.g.
    * tap->doubletap, dwell->dwellend, etc.
    * @type {Function}
    */
   resolveTo: null,
   /**
    * A unique id for the gesture. Composed of the type + timeStamp.
    */
   get id() {
     delete this._id;
     this._id = this.type + this.startTime;
     return this._id;
   },
   /**
    * A gesture promise resolve callback. Compile and emit the gesture.
    * @return {Object} Returns a structure to the gesture handler that looks like
    * this: {
    *   id: current gesture id,
    *   gestureType: an optional subsequent gesture constructor.
    * }
    */
   _handleResolve: function Gesture__handleResolve() {
     if (this.isComplete) {
       return;
     }
     Logger.debug('Resolving', this.id, 'gesture.');
     this.isComplete = true;
     let detail = this.compile();
     if (detail) {
       this._emit(detail);
     }
     return {
       id: this.id,
       gestureType: this.resolveTo
     };
   },
   /**
    * A gesture promise reject callback.
    * @return {Object} Returns a structure to the gesture handler that looks like
    * this: {
    *   id: current gesture id,
    *   gestureType: an optional subsequent gesture constructor.
    * }
    */
   _handleReject: function Gesture__handleReject(aRejectTo) {
     if (this.isComplete) {
       return;
     }
     Logger.debug('Rejecting', this.id, 'gesture.');
     this.isComplete = true;
     return {
       id: this.id,
       gestureType: aRejectTo
     };
   },
   /**
    * A default compilation function used to build the mozAccessFuGesture event
    * detail. The detail always includes the type and the touches associated
    * with the gesture.
    * @return {Object} Gesture event detail.
    */
   compile: function Gesture_compile() {
     return compileDetail(this.type, this.points);
   }
 };
 /**
  * A mixin for an explore related object.
  */
 function ExploreGesture() {
   this.compile = () => {
     // Unlike most of other gestures explore based gestures compile using the
     // current point position and not the start one.
     return compileDetail(this.type, this.points, {x: 'x', y: 'y'});
   };
 }
 /**
  * Check the in progress gesture for completion.
  */
 function checkProgressGesture(aGesture) {
   aGesture._inProgress = true;
   if (aGesture.lastEvent === 'pointerup') {
     if (aGesture.test) {
       aGesture.test(true);
     }
     aGesture._deferred.resolve();
   }
 }
 /**
  * A common travel gesture. When the travel gesture is created, all subsequent
  * pointer events' points are tested for their total distance traveled. If that
  * distance exceeds the _threshold distance, the gesture will be rejected to a
  * _travelTo gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  * @param {Function} aTravelTo A contructor for the gesture to reject to when
  * travelling (default: Explore).
  * @param {Number} aThreshold Travel threshold (default:
  * GestureSettings.travelThreshold).
  */
 function TravelGesture(aTimeStamp, aPoints, aLastEvent, aTravelTo = Explore, aThreshold = GestureSettings.travelThreshold) {
   Gesture.call(this, aTimeStamp, aPoints, aLastEvent);
   this._travelTo = aTravelTo;
   this._threshold = aThreshold;
 }
 TravelGesture.prototype = Object.create(Gesture.prototype);
 /**
  * Test the gesture points for travel. The gesture will be rejected to
  * this._travelTo gesture iff at least one point crosses this._threshold.
  */
 TravelGesture.prototype.test = function TravelGesture_test() {
   for (let identifier in this.points) {
     let point = this.points[identifier];
     if (point.totalDistanceTraveled / Utils.dpi > this._threshold) {
       this._deferred.reject(this._travelTo);
       return;
     }
   }
 };
 /**
  * DwellEnd gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function DwellEnd(aTimeStamp, aPoints, aLastEvent) {
   this._inProgress = true;
   // If the pointer travels, reject to Explore.
   TravelGesture.call(this, aTimeStamp, aPoints, aLastEvent);
   checkProgressGesture(this);
 }
 DwellEnd.prototype = Object.create(TravelGesture.prototype);
 DwellEnd.prototype.type = 'dwellend';
 /**
  * TapHoldEnd gesture. This gesture can be represented as the following diagram:
  * pointerdown-pointerup-pointerdown-*wait*-pointerup.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function TapHoldEnd(aTimeStamp, aPoints, aLastEvent) {
   this._inProgress = true;
   // If the pointer travels, reject to Explore.
   TravelGesture.call(this, aTimeStamp, aPoints, aLastEvent);
   checkProgressGesture(this);
 }
 TapHoldEnd.prototype = Object.create(TravelGesture.prototype);
 TapHoldEnd.prototype.type = 'tapholdend';
 /**
  * DoubleTapHoldEnd gesture. This gesture can be represented as the following
  * diagram:
  * pointerdown-pointerup-pointerdown-pointerup-pointerdown-*wait*-pointerup.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function DoubleTapHoldEnd(aTimeStamp, aPoints, aLastEvent) {
   this._inProgress = true;
   // If the pointer travels, reject to Explore.
   TravelGesture.call(this, aTimeStamp, aPoints, aLastEvent);
   checkProgressGesture(this);
 }
 DoubleTapHoldEnd.prototype = Object.create(TravelGesture.prototype);
 DoubleTapHoldEnd.prototype.type = 'doubletapholdend';
 /**
  * A common tap gesture object.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  * @param {Function} aRejectTo A constructor for the next gesture to reject to
  * in case no pointermove or pointerup happens within the
  * GestureSettings.dwellThreshold.
  * @param {Function} aTravelTo An optional constuctor for the next gesture to
  * reject to in case the the TravelGesture test fails.
  */
 function TapGesture(aTimeStamp, aPoints, aLastEvent, aRejectTo, aTravelTo) {
   this._rejectToOnWait = aRejectTo;
   // If the pointer travels, reject to aTravelTo.
   TravelGesture.call(this, aTimeStamp, aPoints, aLastEvent, aTravelTo,
     TAP_MAX_RADIUS);
 }
 TapGesture.prototype = Object.create(TravelGesture.prototype);
 TapGesture.prototype._getDelay = function TapGesture__getDelay() {
   // If, for TapGesture, no pointermove or pointerup happens within the
   // GestureSettings.dwellThreshold, reject.
   // Note: the original pointer event's timeStamp is irrelevant here.
   return GestureSettings.dwellThreshold;
 };
 /**
  * Tap gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function Tap(aTimeStamp, aPoints, aLastEvent) {
   // If the pointer travels, reject to Swipe.
   TapGesture.call(this, aTimeStamp, aPoints, aLastEvent, Dwell, Swipe);
 }
 Tap.prototype = Object.create(TapGesture.prototype);
 Tap.prototype.type = 'tap';
 Tap.prototype.resolveTo = DoubleTap;
 /**
  * Tap (multi) gesture on Android.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function AndroidTap(aTimeStamp, aPoints, aLastEvent) {
   // If the pointer travels, reject to Swipe. On dwell threshold reject to
   // TapHold.
   TapGesture.call(this, aTimeStamp, aPoints, aLastEvent, TapHold, Swipe);
 }
 AndroidTap.prototype = Object.create(TapGesture.prototype);
 // Android double taps are translated to single taps.
 AndroidTap.prototype.type = 'doubletap';
 AndroidTap.prototype.resolveTo = TripleTap;
 /**
  * Clear the pointerup handler timer in case of the 3 pointer swipe.
  */
 AndroidTap.prototype.clearThreeFingerSwipeTimer = function AndroidTap_clearThreeFingerSwipeTimer() {
   clearTimeout(this._threeFingerSwipeTimer);
   delete this._threeFingerSwipeTimer;
 };
 AndroidTap.prototype.pointerdown = function AndroidTap_pointerdown(aPoints, aTimeStamp) {
   this.clearThreeFingerSwipeTimer();
   TapGesture.prototype.pointerdown.call(this, aPoints, aTimeStamp);
 };
 AndroidTap.prototype.pointermove = function AndroidTap_pointermove(aPoints) {
   this.clearThreeFingerSwipeTimer();
   this._moved = true;
   TapGesture.prototype.pointermove.call(this, aPoints);
 };
 AndroidTap.prototype.pointerup = function AndroidTap_pointerup(aPoints) {
   if (this._moved) {
     // If there was a pointer move - handle the real gesture.
     TapGesture.prototype.pointerup.call(this, aPoints);
   } else {
     // Primptively delay the multi pointer gesture resolution, because Android
     // sometimes fires a pointerdown/poitnerup sequence before the real events.
     this._threeFingerSwipeTimer = setTimeout(() => {
       delete this._threeFingerSwipeTimer;
       TapGesture.prototype.pointerup.call(this, aPoints);
     }, ANDROID_TRIPLE_SWIPE_DELAY);
   }
 };
 /**
  * Reject an android tap gesture.
  * @param  {?Function} aRejectTo An optional next gesture constructor.
  * @return {Object} structure that looks like {
  *   id: gesture_id, // Current AndroidTap gesture id.
  *   gestureType: next_gesture // Optional
  * }
  */
 AndroidTap.prototype._handleReject = function AndroidTap__handleReject(aRejectTo) {
   let keys = Object.keys(this.points);
   if (aRejectTo === Swipe && keys.length === 1) {
     let key = keys[0];
     let point = this.points[key];
     // Two finger swipe is translated into single swipe.
     this.points[key + '-copy'] = point;
   }
   return TapGesture.prototype._handleReject.call(this, aRejectTo);
 };
 /**
  * Double Tap gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function DoubleTap(aTimeStamp, aPoints, aLastEvent) {
   TapGesture.call(this, aTimeStamp, aPoints, aLastEvent, TapHold);
 }
 DoubleTap.prototype = Object.create(TapGesture.prototype);
 DoubleTap.prototype.type = 'doubletap';
 DoubleTap.prototype.resolveTo = TripleTap;
 /**
  * Triple Tap gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function TripleTap(aTimeStamp, aPoints, aLastEvent) {
   TapGesture.call(this, aTimeStamp, aPoints, aLastEvent, DoubleTapHold);
 }
 TripleTap.prototype = Object.create(TapGesture.prototype);
 TripleTap.prototype.type = 'tripletap';
 /**
  * Common base object for gestures that are created as resolved.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function ResolvedGesture(aTimeStamp, aPoints, aLastEvent) {
   Gesture.call(this, aTimeStamp, aPoints, aLastEvent);
   // Resolve the guesture right away.
   this._deferred.resolve();
 }
 ResolvedGesture.prototype = Object.create(Gesture.prototype);
 /**
  * Dwell gesture
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function Dwell(aTimeStamp, aPoints, aLastEvent) {
   ResolvedGesture.call(this, aTimeStamp, aPoints, aLastEvent);
 }
 Dwell.prototype = Object.create(ResolvedGesture.prototype);
 Dwell.prototype.type = 'dwell';
 Dwell.prototype.resolveTo = DwellEnd;
 /**
  * TapHold gesture
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function TapHold(aTimeStamp, aPoints, aLastEvent) {
   ResolvedGesture.call(this, aTimeStamp, aPoints, aLastEvent);
 }
 TapHold.prototype = Object.create(ResolvedGesture.prototype);
 TapHold.prototype.type = 'taphold';
 TapHold.prototype.resolveTo = TapHoldEnd;
 /**
  * DoubleTapHold gesture
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function DoubleTapHold(aTimeStamp, aPoints, aLastEvent) {
   ResolvedGesture.call(this, aTimeStamp, aPoints, aLastEvent);
 }
 DoubleTapHold.prototype = Object.create(ResolvedGesture.prototype);
 DoubleTapHold.prototype.type = 'doubletaphold';
 DoubleTapHold.prototype.resolveTo = DoubleTapHoldEnd;
 /**
  * Explore gesture
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function Explore(aTimeStamp, aPoints, aLastEvent) {
   ExploreGesture.call(this);
   ResolvedGesture.call(this, aTimeStamp, aPoints, aLastEvent);
 }
 Explore.prototype = Object.create(ResolvedGesture.prototype);
 Explore.prototype.type = 'explore';
 Explore.prototype.resolveTo = ExploreEnd;
 /**
  * ExploreEnd gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function ExploreEnd(aTimeStamp, aPoints, aLastEvent) {
   this._inProgress = true;
   ExploreGesture.call(this);
   // If the pointer travels, reject to Explore.
   TravelGesture.call(this, aTimeStamp, aPoints, aLastEvent);
   checkProgressGesture(this);
 }
 ExploreEnd.prototype = Object.create(TravelGesture.prototype);
 ExploreEnd.prototype.type = 'exploreend';
 /**
  * Swipe gesture.
  * @param {Number} aTimeStamp An original pointer event's timeStamp that started
  * the gesture resolution sequence.
  * @param {Object} aPoints An existing set of points (from previous events).
  * @param {?String} aLastEvent Last pointer event type.
  */
 function Swipe(aTimeStamp, aPoints, aLastEvent) {
   this._inProgress = true;
   this._rejectToOnWait = Explore;
   Gesture.call(this, aTimeStamp, aPoints, aLastEvent);
   checkProgressGesture(this);
 }
 Swipe.prototype = Object.create(Gesture.prototype);
 Swipe.prototype.type = 'swipe';
 Swipe.prototype._getDelay = function Swipe__getDelay(aTimeStamp) {
   // Swipe should be completed within the GestureSettings.swipeMaxDuration from
   // the initial pointer down event.
   return GestureSettings.swipeMaxDuration - this.startTime + aTimeStamp;
 };
 /**
  * Determine wither the gesture was Swipe or Explore.
  * @param  {Booler} aComplete A flag that indicates whether the gesture is and
  * will be complete after the test.
  */
 Swipe.prototype.test = function Swipe_test(aComplete) {
   if (!aComplete) {
     // No need to test if the gesture is not completing or can't be complete.
     return;
   }
   let reject = true;
   // If at least one point travelled for more than SWIPE_MIN_DISTANCE and it was
   // direct enough, consider it a Swipe.
   for (let identifier in this.points) {
     let point = this.points[identifier];
     let directDistance = point.directDistanceTraveled;
     if (directDistance / Utils.dpi >= SWIPE_MIN_DISTANCE ||
       directDistance * DIRECTNESS_COEFF >= point.totalDistanceTraveled) {
       reject = false;
     }
   }
   if (reject) {
     this._deferred.reject(Explore);
   }
 };
 /**
  * Compile a swipe related mozAccessFuGesture event detail.
  * @return {Object} A mozAccessFuGesture detail object.
  */
 Swipe.prototype.compile = function Swipe_compile() {
   let type = this.type;
   let detail = compileDetail(type, this.points,
     {x1: 'startX', y1: 'startY', x2: 'x', y2: 'y'});
   let deltaX = detail.deltaX;
   let deltaY = detail.deltaY;
   if (Math.abs(deltaX) > Math.abs(deltaY)) {
     // Horizontal swipe.
     detail.type = type + (deltaX > 0 ? 'right' : 'left');
   } else {
     // Vertival swipe.
     detail.type = type + (deltaY > 0 ? 'down' : 'up');
   }
   return detail;
 };

The Tor Browser / annotate

accessible/src/jsat/Gestures.jsm@141e0f1194b1 (annotated)

accessible/src/jsat/Gestures.jsm