As the sun rises and the forest mist clears, and the clouds return and the caves darken, these changes of light and shadow are the morning and evening in the mountains. Wildflowers bloom with their subtle fragrance, fine trees flourish with their dense shade, the wind and frost are pure and clean, and the water recedes to reveal the rocks—these are the four seasons in the mountains. Going out in the morning and returning in the evening, the scenery of the four seasons is different, and the joy is endless.至于负者歌于途,行者休于树,前者呼,后者应,伛偻提携,往来而不绝者,滁人游也。临溪而渔,溪深而鱼肥,酿泉为酒,泉香而酒洌,山肴野蔌,杂然而前陈者,太守宴也。宴酣之乐,非丝非竹,射者中,弈者胜,觥筹交错,起坐而喧哗者,众宾欢也。苍颜白发,颓然乎其间者,太守醉也。
/*!
* hoverIntent v1.10.2 // 2020.04.28 // jQuery v1.7.0+
* http://briancherne.github.io/jquery-hoverIntent/
*
* You may use hoverIntent under the terms of the MIT license. Basically that
* means you are free to use hoverIntent as long as this header is left intact.
* Copyright 2007-2019 Brian Cherne
*/
/**
* hoverIntent is similar to jQuery's built-in "hover" method except that
* instead of firing the handlerIn function immediately, hoverIntent checks
* to see if the user's mouse has slowed down (beneath the sensitivity
* threshold) before firing the event. The handlerOut function is only
* called after a matching handlerIn.
*
* // basic usage ... just like .hover()
* .hoverIntent( handlerIn, handlerOut )
* .hoverIntent( handlerInOut )
*
* // basic usage ... with event delegation!
* .hoverIntent( handlerIn, handlerOut, selector )
* .hoverIntent( handlerInOut, selector )
*
* // using a basic configuration object
* .hoverIntent( config )
*
* @param handlerIn function OR configuration object
* @param handlerOut function OR selector for delegation OR undefined
* @param selector selector OR undefined
* @author Brian Cherne <brian(at)cherne(dot)net>
*/
;(function(factory) {
'use strict';
if (typeof define === 'function' && define.amd) {
define(['jquery'], factory);
} else if (typeof module === 'object' && module.exports) {
module.exports = factory(require('jquery'));
} else if (jQuery && !jQuery.fn.hoverIntent) {
factory(jQuery);
}
})(function($) {
'use strict';
// default configuration values
var _cfg = {
interval: 100,
sensitivity: 6,
timeout: 0
};
// counter used to generate an ID for each instance
var INSTANCE_COUNT = 0;
// current X and Y position of mouse, updated during mousemove tracking (shared across instances)
var cX, cY;
// saves the current pointer position coordinates based on the given mousemove event
var track = function(ev) {
cX = ev.pageX;
cY = ev.pageY;
};
// compares current and previous mouse positions
var compare = function(ev,$el,s,cfg) {
// compare mouse positions to see if pointer has slowed enough to trigger `over` function
if ( Math.sqrt( (s.pX-cX)*(s.pX-cX) + (s.pY-cY)*(s.pY-cY) ) < cfg.sensitivity ) {
$el.off(s.event,track);
delete s.timeoutId;
// set hoverIntent state as active for this element (permits `out` handler to trigger)
s.isActive = true;
// overwrite old mouseenter event coordinates with most recent pointer position
ev.pageX = cX; ev.pageY = cY;
// clear coordinate data from state object
delete s.pX; delete s.pY;
return cfg.over.apply($el[0],[ev]);
} else {
// set previous coordinates for next comparison
s.pX = cX; s.pY = cY;
// use self-calling timeout, guarantees intervals are spaced out properly (avoids JavaScript timer bugs)
s.timeoutId = setTimeout( function(){compare(ev, $el, s, cfg);} , cfg.interval );
}
};
// triggers given `out` function at configured `timeout` after a mouseleave and clears state
var delay = function(ev,$el,s,out) {
var data = $el.data('hoverIntent');
if (data) {
delete data[s.id];
}
return out.apply($el[0],[ev]);
};
// checks if `value` is a function
var isFunction = function(value) {
return typeof value === 'function';
};
$.fn.hoverIntent = function(handlerIn,handlerOut,selector) {
// instance ID, used as a key to store and retrieve state information on an element
var instanceId = INSTANCE_COUNT++;
// extend the default configuration and parse parameters
var cfg = $.extend({}, _cfg);
if ( $.isPlainObject(handlerIn) ) {
cfg = $.extend(cfg, handlerIn);
if ( !isFunction(cfg.out) ) {
cfg.out = cfg.over;
}
} else if ( isFunction(handlerOut) ) {
cfg = $.extend(cfg, { over: handlerIn, out: handlerOut, selector: selector } );
} else {
cfg = $.extend(cfg, { over: handlerIn, out: handlerIn, selector: handlerOut } );
}
// A private function for handling mouse 'hovering'
var handleHover = function(e) {
// cloned event to pass to handlers (copy required for event object to be passed in IE)
var ev = $.extend({},e);
// the current target of the mouse event, wrapped in a jQuery object
var $el = $(this);
// read hoverIntent data from element (or initialize if not present)
var hoverIntentData = $el.data('hoverIntent');
if (!hoverIntentData) { $el.data('hoverIntent', (hoverIntentData = {})); }
// read per-instance state from element (or initialize if not present)
var state = hoverIntentData[instanceId];
if (!state) { hoverIntentData[instanceId] = state = { id: instanceId }; }
// state properties:
// id = instance ID, used to clean up data
// timeoutId = timeout ID, reused for tracking mouse position and delaying "out" handler
// isActive = plugin state, true after `over` is called just until `out` is called
// pX, pY = previously-measured pointer coordinates, updated at each polling interval
// event = string representing the namespaced event used for mouse tracking
// clear any existing timeout
if (state.timeoutId) { state.timeoutId = clearTimeout(state.timeoutId); }
// namespaced event used to register and unregister mousemove tracking
var mousemove = state.event = 'mousemove.hoverIntent.hoverIntent'+instanceId;
// handle the event, based on its type
if (e.type === 'mouseenter') {
// do nothing if already active
if (state.isActive) { return; }
// set "previous" X and Y position based on initial entry point
state.pX = ev.pageX; state.pY = ev.pageY;
// update "current" X and Y position based on mousemove
$el.off(mousemove,track).on(mousemove,track);
// start polling interval (self-calling timeout) to compare mouse coordinates over time
state.timeoutId = setTimeout( function(){compare(ev,$el,state,cfg);} , cfg.interval );
} else { // "mouseleave"
// do nothing if not already active
if (!state.isActive) { return; }
// unbind expensive mousemove event
$el.off(mousemove,track);
// if hoverIntent state is true, then call the mouseOut function after the specified delay
state.timeoutId = setTimeout( function(){delay(ev,$el,state,cfg.out);} , cfg.timeout );
}
};
// listen for mouseenter and mouseleave
return this.on({'mouseenter.hoverIntent':handleHover,'mouseleave.hoverIntent':handleHover}, cfg.selector);
};
});