source: Dev/trunk/src/client/dojox/gesture/swipe.js

define([
        "dojo/_base/kernel",
        "dojo/_base/declare",
        "./Base",
        "../main"
], function(kernel, declare, Base, dojox){
// module:
//              dojox/gesture/swipe

/*=====
        dojox.gesture.swipe = {
                // summary:
                //              This module provides swipe gestures including:
                //
                //              ####dojox.gesture.swipe
                //
                //              A series of 'swipe' will be fired during touchmove, this will mostly
                //              be used to keep sliding the Dom target based on the swiped distance(dx, dy).
                //
                //              ####dojox.gesture.swipe.end
                //      
                //              Fired when a swipe is ended so that an bounce animation may be applied
                //              to the dom target sliding to the final position.
                //
                //              Following information will be included in the fired swipe events:
                //
                //              1. type: 'swipe'|'swipe.end'
                //              2. time: an integer indicating the delta time(in milliseconds)
                //              3. dx: delta distance on X axis, dx less than 0 - moving left, dx larger than 0 - moving right
                //              4. dy: delta distance on Y axis, dy less than 0 - moving up, dY larger than 0 - moving down
                //
                //              Note - dx and dy can also be used together for a hybrid swipe(both vertically and horizontally)
                //
                // example:
                //              A. Used with dojo.connect()
                //              |       dojo.connect(node, dojox.gesture.swipe, function(e){});
                //              |       dojo.connect(node, dojox.gesture.swipe.end, function(e){});
                //
                //              B. Used with dojo.on
                //              |       define(['dojo/on', 'dojox/gesture/swipe'], function(on, swipe){
                //              |               on(node, swipe, function(e){});
                //              |               on(node, swipe.end, function(e){});
                //
                //              C. Used with dojox.gesture.swipe.* directly
                //              |       dojox.gesture.swipe(node, function(e){});
                //              |       dojox.gesture.swipe.end(node, function(e){});
        };
=====*/

kernel.experimental("dojox.gesture.swipe");

// Declare an internal anonymous class which will only be exported
// by module return value e.g. dojox.gesture.swipe.Swipe
var clz = declare(/*===== "dojox.gesture.swipe", =====*/Base, {

        // defaultEvent: [readonly] String
        //              Default event - 'swipe'
        defaultEvent: "swipe",

        // subEvents: [readonly] Array
        //              List of sub events, used by 
        //              being combined with defaultEvent as 'swipe.end'
        subEvents: ["end"],

        press: function(/*Object*/data, /*Event*/e){
                // summary:
                //              Overwritten, set initial swipe info
                if(e.touches && e.touches.length >= 2){
                        //currently only support single-touch swipe
                        delete data.context;
                        return;
                }
                if(!data.context){
                        data.context = {x: 0, y: 0, t: 0};
                }
                data.context.x = e.screenX;
                data.context.y = e.screenY;
                data.context.t = new Date().getTime();
                this.lock(e.currentTarget);
        },
        move: function(/*Object*/data, /*Event*/e){
                // summary:
                //              Overwritten, fire matched 'swipe' during touchmove
                this._recognize(data, e, "swipe");
        },
        release: function(/*Object*/data, /*Event*/e){
                // summary:
                //              Overwritten, fire matched 'swipe.end' when touchend
                this._recognize(data, e, "swipe.end");          
                delete data.context;
                this.unLock();
        },
        cancel: function(data, e){
                // summary:
                //              Overwritten
                delete data.context;
                this.unLock();
        },
        _recognize: function(/*Object*/data, /*Event*/e, /*String*/type){
                // summary:
                //              Recognize and fire appropriate gesture events
                if(!data.context){
                        return;
                }
                var info = this._getSwipeInfo(data, e);
                if(!info){
                        // no swipe happened
                        return;
                }
                info.type = type;
                this.fire(e.target, info);
        },
        _getSwipeInfo: function(/*Object*/data, /*Event*/e){
                // summary:
                //              Calculate swipe information - time, dx and dy
                var dx, dy, info = {}, startData = data.context;
                
                info.time = new Date().getTime() - startData.t;
                
                dx = e.screenX - startData.x;
                dy = e.screenY - startData.y;
                
                if(dx === 0 && dy === 0){
                        // no swipes happened
                        return null;
                }
                info.dx = dx;
                info.dy = dy;
                return info;
        }
});

// the default swipe instance for handy use
dojox.gesture.swipe = new clz();
// Class for creating a new Swipe instance
dojox.gesture.swipe.Swipe = clz;

return dojox.gesture.swipe;

});