event-gestures/js/Move.js

	Move.js revision 35a16952b0308d5bf01f468c2e748bd2895a4bdf
// TODO: Better way to sniff 'n' switch touch support?

var EVENT = ("ontouchstart" in Y.config.win) ? {
        start: "touchstart",
        move: "touchmove",
        end: "touchend"
    } : {
        start: "mousedown",
        move: "mousemove",
        end: "mouseup"
    },

    START = "start",
    MOVE = "move",
    END = "end",

    _MOVE_START_HANDLE = "_msh",
    _MOVE_HANDLE = "_mh",
    _MOVE_END_HANDLE = "_meh",

    _MOVE_START = "_ms",
    _MOVE = "_m",

    MIN_TIME = "minTime",
    MIN_DISTANCE = "minDistance",
    OWNER_DOCUMENT = "ownerDocument",

    NODE_TYPE = "nodeType",

    PUB_CFG = {
        emitFacade:false
    },

    // TODO: Should this be in SynthEvent as the default?
    _defArgsProcessor = function(args) {
        return args[3] ? args.splice(3,1)[0] : {};
    },

    _getRoot = function(node, subscriber) {
        return subscriber._extra.root || (node.get(NODE_TYPE) === 9) ? node : node.get(OWNER_DOCUMENT);
    },

    define = Y.Event.define;

define('movestart', {

    init: function (node, subscriber, ce) {

        node.setData(_MOVE_START_HANDLE, node.on(EVENT[START],
            this._onStart,
            this,
            node,
            subscriber,
            ce));

    },

    destroy: function (node, subscriber, ce) {
        var startHandle = node.getData(_MOVE_START_HANDLE);

        if (startHandle) {
            startHandle.detach();
            node.clearData(_MOVE_START_HANDLE);
        }
    },

    processArgs : function(args) {
        var params = _defArgsProcessor(args);

        if (!(MIN_TIME in params)) {
            params[MIN_TIME] = this.MIN_TIME;
        }

        if (!(MIN_DISTANCE in params)) {
            params[MIN_DISTANCE] = this.MIN_DISTANCE;
        }

        return params;
    },

    publishConfig: PUB_CFG,

    _onStart : function(e, node, subscriber, ce) {

        e.preventDefault();

        var start = true,
            origE = e; // always true for mouse

        if (e.touches) {
            start = (e.touches.length === 1);
            e = e.touches[0];

            e.target = e.target || origE.target;
            e.currentTarget = e.currentTarget || origE.currentTarget;
        }

        if (start) {
            e.type = "movestart";
            node.setData(_MOVE_START, e);
            ce.fire(e);
        }
    },

    MIN_TIME : 0,
    MIN_DISTANCE : 3
});

define('move', {

    init : function (node, subscriber, ce) {

        var root = _getRoot(node, subscriber),

            moveHandle = root.on(EVENT[MOVE],
                this._onMove,
                this,
                node,
                subscriber,
                ce);

        node.setData(_MOVE_HANDLE, moveHandle);
    },

    processArgs : _defArgsProcessor,

    destroy : function (node, subscriber, ce) {
        var moveHandle = node.getData(_MOVE_HANDLE);

        if (moveHandle) {
            moveHandle.detach();
            node.clearData(_MOVE_HANDLE);
        }
    },

    publishConfig : PUB_CFG,

    _onMove : function(e, node, subscriber, ce) {

        var move = subscriber._extra.standAlone || node.getData(_MOVE_START),
            origE = e;

        if (move) {

            if (e.touches) {
                move = (e.touches.length === 1);
                e = e.touches[0];

                e.target = e.target || origE.target;
                e.currentTarget = e.currentTarget || origE.currentTarget;
            }

            if (move) {
                origE.preventDefault();

                e.type = "move";
                node.setData(_MOVE, e);
                ce.fire(e);
            }
        }
    }
});

define('moveend', {

    init : function (node, subscriber, ce) {

        var root = _getRoot(node, subscriber),

            endHandle = root.on(EVENT[END],
                this._onEnd,
                this,
                node,
                subscriber,
                ce);

        node.setData(_MOVE_END_HANDLE, endHandle);
    },

    processArgs : _defArgsProcessor,

    destroy : function (node, subscriber, ce) {
        var endHandle = node.getData(_MOVE_END_HANDLE);

        if (endHandle) {
            endHandle.detach();
            node.clearData(_MOVE_END_HANDLE);
        }
    },

    publishConfig : PUB_CFG,

    _onEnd : function(e, node, subscriber, ce) {

        var moveEnd = subscriber._extra.standAlone || node.getData(_MOVE) || node.getData(_MOVE_START),
            origE = e;

        if (moveEnd) {

            if (e.changedTouches) {
                if (e.changedTouches.length === 1) {
                    e = e.changedTouches[0];

                    e.target = e.target || origE.target;
                    e.currentTarget = e.currentTarget || origE.currentTarget;

                } else {
                    moveEnd = false;
                }
            }

            if (moveEnd) {
                origE.preventDefault();
                e.type = "moveend";

                node.clearData(_MOVE_START);
                node.clearData(_MOVE);

                ce.fire(e);
            }
        }
    }
});