source: trunk/www.guidonia.net/wp/wp-includes/js/hoverIntent.dev.js@ 44

/**
* hoverIntent is similar to jQuery's built-in "hover" function except that
* instead of firing the onMouseOver event immediately, hoverIntent checks
* to see if the user's mouse has slowed down (beneath the sensitivity
* threshold) before firing the onMouseOver event.
* 
* hoverIntent r5 // 2007.03.27 // jQuery 1.1.2+
* <http://cherne.net/brian/resources/jquery.hoverIntent.html>
* 
* hoverIntent is currently available for use in all personal or commercial 
* projects under both MIT and GPL licenses. This means that you can choose 
* the license that best suits your project, and use it accordingly.
* 
* // basic usage (just like .hover) receives onMouseOver and onMouseOut functions
* $("ul li").hoverIntent( showNav , hideNav );
* 
* // advanced usage receives configuration object only
* $("ul li").hoverIntent({
*       sensitivity: 7, // number = sensitivity threshold (must be 1 or higher)
*       interval: 100,   // number = milliseconds of polling interval
*       over: showNav,  // function = onMouseOver callback (required)
*       timeout: 0,   // number = milliseconds delay before onMouseOut function call
*       out: hideNav    // function = onMouseOut callback (required)
* });
* 
* @param  f  onMouseOver function || An object with configuration options
* @param  g  onMouseOut function  || Nothing (use configuration options object)
* @author    Brian Cherne <brian@cherne.net>
*/
(function($) {
        $.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]);
                };
                
                // workaround for Mozilla bug: not firing mouseout/mouseleave on absolute positioned elements over textareas and input type="text"
                var handleHover = function(e) {
                        var t = this;
                        
                        // next two 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 ) {
                                if ( $.browser.mozilla ) {
                                        if ( e.type == "mouseout" ) {
                                                t.mtout = setTimeout( function(){doHover(e,t);}, 30 );
                                        } else {
                                                if (t.mtout) { t.mtout = clearTimeout(t.mtout); }
                                        }
                                }
                                return;
                        } else {
                                if (t.mtout) { t.mtout = clearTimeout(t.mtout); }
                                doHover(e,t);
                        }
                };

                // A private function for handling mouse 'hovering'
                var doHover = function(e,ob) {

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

                        // 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);