3 Copyright 2012 Yahoo! Inc. All rights reserved.
4 Licensed under the BSD License.
5 http://yuilibrary.com/license/
7 YUI.add('event-flick', function(Y) {
10 * The gestures module provides gesture events such as "flick", which normalize user interactions
11 * across touch and mouse or pointer based input devices. This layer can be used by application developers
12 * to build input device agnostic components which behave the same in response to either touch or mouse based
15 * <p>Documentation for events added by this module can be found in the event document for the <a href="YUI.html#events">YUI</a> global.</p>
17 * @module event-gestures
21 * Adds support for a "flick" event, which is fired at the end of a touch or mouse based flick gesture, and provides
22 * velocity of the flick, along with distance and time information.
24 * @module event-gestures
25 * @submodule event-flick
28 var EVENT = ((Y.config.win && ("ontouchstart" in Y.config.win)) && !(Y.UA.chrome && Y.UA.chrome < 6)) ? {
42 OWNER_DOCUMENT = "ownerDocument",
43 MIN_VELOCITY = "minVelocity",
44 MIN_DISTANCE = "minDistance",
45 PREVENT_DEFAULT = "preventDefault",
48 _FLICK_START_HANDLE = "_fsh",
49 _FLICK_END_HANDLE = "_feh",
50 _FLICK_MOVE_HANDLE = "_fmh",
52 NODE_TYPE = "nodeType";
55 * Sets up a "flick" event, that is fired whenever the user initiates a flick gesture on the node
56 * where the listener is attached. The subscriber can specify a minimum distance or velocity for
57 * which the event is to be fired. The subscriber can also specify if there is a particular axis which
58 * they are interested in - "x" or "y". If no axis is specified, the axis along which there was most distance
61 * <p>It is recommended that you use Y.bind to set up context and additional arguments for your event handler,
62 * however if you want to pass the context and arguments as additional signature arguments to "on",
63 * you need to provide a null value for the configuration object, e.g: <code>node.on("flick", fn, null, context, arg1, arg2, arg3)</code></p>
67 * @param type {string} "flick"
68 * @param fn {function} The method the event invokes. It receives an event facade with an e.flick object containing the flick related properties: e.flick.time, e.flick.distance, e.flick.velocity and e.flick.axis, e.flick.start.
69 * @param cfg {Object} Optional. An object which specifies any of the following:
71 * <dt>minDistance (in pixels, defaults to 10)</dt>
72 * <dd>The minimum distance between start and end points, which would qualify the gesture as a flick.</dd>
73 * <dt>minVelocity (in pixels/ms, defaults to 0)</dt>
74 * <dd>The minimum velocity which would qualify the gesture as a flick.</dd>
75 * <dt>preventDefault (defaults to false)</dt>
76 * <dd>Can be set to true/false to prevent default behavior as soon as the touchstart/touchend or mousedown/mouseup is received so that things like scrolling or text selection can be
77 * prevented. This property can also be set to a function, which returns true or false, based on the event facade passed to it.</dd>
78 * <dt>axis (no default)</dt>
79 * <dd>Can be set to "x" or "y" if you want to constrain the flick velocity and distance to a single axis. If not
80 * defined, the axis along which the maximum distance was covered is used.</dd>
82 * @return {EventHandle} the detach handle
85 Y.Event.define('flick', {
87 on: function (node, subscriber, ce) {
89 var startHandle = node.on(EVENT[START],
96 subscriber[_FLICK_START_HANDLE] = startHandle;
99 detach: function (node, subscriber, ce) {
101 var startHandle = subscriber[_FLICK_START_HANDLE],
102 endHandle = subscriber[_FLICK_END_HANDLE];
105 startHandle.detach();
106 subscriber[_FLICK_START_HANDLE] = null;
111 subscriber[_FLICK_END_HANDLE] = null;
115 processArgs: function(args) {
116 var params = (args.length > 3) ? Y.merge(args.splice(3, 1)[0]) : {};
118 if (!(MIN_VELOCITY in params)) {
119 params[MIN_VELOCITY] = this.MIN_VELOCITY;
122 if (!(MIN_DISTANCE in params)) {
123 params[MIN_DISTANCE] = this.MIN_DISTANCE;
126 if (!(PREVENT_DEFAULT in params)) {
127 params[PREVENT_DEFAULT] = this.PREVENT_DEFAULT;
133 _onStart: function(e, node, subscriber, ce) {
135 var start = true, // always true for mouse
139 preventDefault = subscriber._extra.preventDefault,
143 start = (e.touches.length === 1);
149 if (preventDefault) {
150 // preventDefault is a boolean or function
151 if (!preventDefault.call || preventDefault(e)) {
152 origE.preventDefault();
157 time : new Date().getTime()
160 subscriber[_FLICK_START] = e;
162 endHandle = subscriber[_FLICK_END_HANDLE];
164 doc = (node.get(NODE_TYPE) === 9) ? node : node.get(OWNER_DOCUMENT);
166 endHandle = doc.on(EVENT[END], Y.bind(this._onEnd, this), null, node, subscriber, ce);
167 subscriber[_FLICK_END_HANDLE] = endHandle;
170 subscriber[_FLICK_MOVE_HANDLE] = doc.once(EVENT[MOVE], Y.bind(this._onMove, this), null, node, subscriber, ce);
174 _onMove: function(e, node, subscriber, ce) {
175 var start = subscriber[_FLICK_START];
177 // Start timing from first move.
178 if (start && start.flick) {
179 start.flick.time = new Date().getTime();
183 _onEnd: function(e, node, subscriber, ce) {
185 var endTime = new Date().getTime(),
186 start = subscriber[_FLICK_START],
197 moveHandle = subscriber[_FLICK_MOVE_HANDLE];
201 delete subscriber[_FLICK_MOVE_HANDLE];
206 if (e.changedTouches) {
207 if (e.changedTouches.length === 1 && e.touches.length === 0) {
208 endEvent = e.changedTouches[0];
216 params = subscriber._extra;
217 preventDefault = params[PREVENT_DEFAULT];
219 if (preventDefault) {
220 // preventDefault is a boolean or function
221 if (!preventDefault.call || preventDefault(e)) {
226 startTime = start.flick.time;
227 endTime = new Date().getTime();
228 time = endTime - startTime;
231 endEvent.pageX - start.pageX,
232 endEvent.pageY - start.pageY
238 axis = (Math.abs(xyDistance[0]) >= Math.abs(xyDistance[1])) ? 'x' : 'y';
241 distance = xyDistance[(axis === 'x') ? 0 : 1];
242 velocity = (time !== 0) ? distance/time : 0;
244 if (isFinite(velocity) && (Math.abs(distance) >= params[MIN_DISTANCE]) && (Math.abs(velocity) >= params[MIN_VELOCITY])) {
259 subscriber[_FLICK_START] = null;
266 PREVENT_DEFAULT : false
270 }, '3.5.0' ,{requires:['node-base','event-touch','event-synthetic']});