<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>鼠标移入移出方向判断</title>
<style>
*{
margin: 0;
padding: 0;
}
body {
padding-top: 100px;
text-align: center;
}
.tips {
100%;
height: 30px;
position: absolute;
overflow: hidden;
bottom: 0;
left:0;
}
.content {
position: absolute;
z-index: 2;
background: #000;
opacity: 0.7;
100%;
height:100%;
left: -100%;
top: -100%;
line-height: 30px;
text-align: center;
color: #fff;
font-size: 18px;
}
.content.trans {
transition: all .2s;
backface-visibility: hidden;
}
.box{
200px;
height: 250px;
margin: 20px;
display: inline-block;
position: relative;
background: #5587be;
}
</style>
<script src="jq/js/jquery-1.12.4.min.js"></script>
</head>
<body>
<div class="box">
<div class="tips">
<div class="content">
1
</div>
</div>
</div>
<div class="box">
<div class="tips">
<div class="content">
2
</div>
</div>
</div>
<div class="box">
<div class="tips">
<div class="content">
3
</div>
</div>
</div>
<div class="box">
<div class="tips">
<div class="content">
4
</div>
</div>
</div>
<script>
var DIR_POS = {
left: {
top: '0',
left: '-100%'
},
right: {
top: '0',
left: '100%'
},
bottom: {
top: '100%',
left: '0'
},
top: {
top: '-100%',
left: '0'
}
};
// 判断鼠标方向
var MouseDirection = function (element, opts) {
var $element = $(element);
//enter leave代表鼠标移入移出时的回调
opts = $.extend({}, {
enter: $.noop,
leave: $.noop
}, opts || {});
var dirs = ['top', 'right', 'bottom', 'left'];
var calculate = function (element, e) {
/*以浏览器可视区域的左上角建立坐标系*/
//表示左上角和右下角及中心点坐标
var x1, y1, x4, y4, x0, y0;
//表示左上角和右下角的对角线斜率
var k;
//用getBoundingClientRect比较省事，而且它的兼容性还不错
var rect = element.getBoundingClientRect();
//求各个点坐标 注意y坐标应该转换为负值，因为浏览器可视区域左上角为(0,0)，整个可视区域属于第四象限
x1 = rect.left;
y1 = -rect.top;
x4 = rect.left + rect.width;
y4 = -(rect.top + rect.height);
x0 = rect.left + rect.width / 2;
y0 = -(rect.top + rect.height / 2);
//矩形不够大，不考虑
if (Math.abs(x1 - x4) < 0.0001) return 4;
//计算对角线斜率
k = (y1 - y4) / (x1 - x4);
var range = [k, -k];
//表示鼠标当前位置的点坐标
var x, y;
x = e.clientX;
y = -e.clientY;
//表示鼠标当前位置的点与元素中心点连线的斜率
var kk;
kk = (y - y0) / (x - x0);
//如果斜率在range范围内，则鼠标是从左右方向移入移出的
if (isFinite(kk) && range[0] < kk && kk < range[1]) {
//根据x与x0判断左右
return x > x0 ? 1 : 3;
} else {
//根据y与y0判断上下
return y > y0 ? 0 : 2;
}
};
$element.on('mouseenter', function (e) {
var r = calculate(this, e);
opts.enter($element, dirs[r]);
}).on('mouseleave', function (e) {
var r = calculate(this, e);
opts.leave($element, dirs[r]);
});
};
$('.box').each(function () {
MouseDirection(this, {
enter: function ($element, dir) {
//每次进入前先把.trans类移除掉，以免后面调整位置的时候也产生过渡效果
var $content = $element.find('.content').removeClass('trans');
//调整位置
$content.css(DIR_POS[dir]);
//reflow
$content[0].offsetWidth;
//启用过渡
$content.addClass('trans');
//滑入
$content.css({left: '0', top: '0'});
},
leave: function ($element, dir) {
$element.find('.content').css(DIR_POS[dir]);
}
});
});
</script>
</body>
</html>