source: documentation/trunk/tutorial_sample_files/libraries/althor/js/superfish-1.4.8/js/hoverIntent.js@ 28599

(function($){
    /* hoverIntent by Brian Cherne */
    $.fn.hoverIntent = function(f,g) {
        // default configuration options
        var cfg = {
            sensitivity: 7,
            interval: 100,
            timeout: 0
        };
        // override configuration options with user supplied object
        cfg = $.extend(cfg, g ? { over: f, out: g } : f );

        // instantiate variables
        // cX, cY = current X and Y position of mouse, updated by mousemove event
        // pX, pY = previous X and Y position of mouse, set by mouseover and polling interval
        var cX, cY, pX, pY;

        // A private function for getting mouse position
        var track = function(ev) {
            cX = ev.pageX;
            cY = ev.pageY;
        };

        // A private function for comparing current and previous mouse position
        var compare = function(ev,ob) {
            ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t);
            // compare mouse positions to see if they've crossed the threshold
            if ( ( Math.abs(pX-cX) + Math.abs(pY-cY) ) < cfg.sensitivity ) {
                $(ob).unbind("mousemove",track);
                // set hoverIntent state to true (so mouseOut can be called)
                ob.hoverIntent_s = 1;
                return cfg.over.apply(ob,[ev]);
            } else {
                // set previous coordinates for next time
                pX = cX; pY = cY;
                // use self-calling timeout, guarantees intervals are spaced out properly (avoids JavaScript timer bugs)
                ob.hoverIntent_t = setTimeout( function(){compare(ev, ob);} , cfg.interval );
            }
        };

        // A private function for delaying the mouseOut function
        var delay = function(ev,ob) {
            ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t);
            ob.hoverIntent_s = 0;
            return cfg.out.apply(ob,[ev]);
        };

        // A private function for handling mouse 'hovering'
        var handleHover = function(e) {
            // next three lines copied from jQuery.hover, ignore children onMouseOver/onMouseOut
            var p = (e.type == "mouseover" ? e.fromElement : e.toElement) || e.relatedTarget;
            while ( p && p != this ) { try { p = p.parentNode; } catch(e) { p = this; } }
            if ( p == this ) { return false; }

            // copy objects to be passed into t (required for event object to be passed in IE)
            var ev = jQuery.extend({},e);
            var ob = this;

            // cancel hoverIntent timer if it exists
            if (ob.hoverIntent_t) { ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t); }

            // else e.type == "onmouseover"
            if (e.type == "mouseover") {
                // set "previous" X and Y position based on initial entry point
                pX = ev.pageX; pY = ev.pageY;
                // update "current" X and Y position based on mousemove
                $(ob).bind("mousemove",track);
                // start polling interval (self-calling timeout) to compare mouse coordinates over time
                if (ob.hoverIntent_s != 1) { ob.hoverIntent_t = setTimeout( function(){compare(ev,ob);} , cfg.interval );}

            // else e.type == "onmouseout"
            } else {
                // unbind expensive mousemove event
                $(ob).unbind("mousemove",track);
                // if hoverIntent state is true, then call the mouseOut function after the specified delay
                if (ob.hoverIntent_s == 1) { ob.hoverIntent_t = setTimeout( function(){delay(ev,ob);} , cfg.timeout );}
            }
        };

        // bind the function to the two event listeners
        return this.mouseover(handleHover).mouseout(handleHover);
    };
    
})(jQuery);