实现鼠标悬停,div勾画div边框的动画

鼠标悬浮,边框div边框的动画样式,效果图如下:

首先定义div及其样式:

 1 <style>
 2   .show
 3   {
 4        width:300px;
 5        height:200px;
 6        border:1px solid red;
 7        background:yellow;
 8 } 
 9 </style>
10 <div class="show"></div>

界面展示效果如下:

通过指定样式clip来指定,裁剪的区域:

然后需要做的是将这个裁剪过程用动画连贯起来,修改css样式

 1    .show
 2     {
 3         position: absolute;
 4         width: 300px;
 5         height: 200px;
 6         top: 400px;
 7         left: 400px;
 8         bottom: 400px;
 9         right: 400px;
10         border:1px solid red;
11         animation: ClipAfter 4s linear infinite;
12         background: yellow;
13     }
14     @keyframes ClipAfter {
15         0%, 100% {
16             /*为了在动画过程中能保留右边框和下边框,rect的right和bottom分别多取两个像素*/
17             /*为了在动画的终点和起点不要显示上边框和左边框,rect的top和left分别多取了一个像素*/
18             clip: rect(1px,302px,202px,1px);
19         }
20         25% {
21             clip: rect(100px,302px,202px,150px);
22         }
23 
24         50% {
25             clip: rect(200px,302px,202px,300px);
26         }
27         75% {
28             clip: rect(100px,302px,202px,150px);
29         }
30     }

更改之后的效果图如下:

同样可以定义出保留上边框和左边框的动画样式:

 1   @keyframes ClipBefore {
 2         100%,0%{
 3             clip:rect(0px,300px,200px,0px);
 4         }
 5         25%
 6         {
 7             clip:rect(0px,150px,100px,0px);
 8         }
 9         50%{
10             clip:rect(0px,0px,0px,0px);
11         }
12         75%{
13             clip:rect(0px,150px,100px,0px);
14         }
15     }

由于开篇示例中的动画,是左上,和右下方边框的动画是同步进行的,所以使用div的伪类before(实现左上边框动画),after(实现右下边框动画)

css:

  1     .region-wrap {
  2         width: 320px;
  3         height: 220px;
  4         border: 1px solid #f4f4f4;
  5     }
  6 
  7     .region {
  8         position: absolute;
  9     }
 10     .content
 11     {
 12         position:  absolute;
 13         top: 10px;
 14         left: 10px;
 15         width: 300px;
 16         height: 200px;
 17         border:1px solid #aa0507;
 18     }
 19     .content:before,.content:after
 20     {
 21         position: absolute;
 22         top: 0;
 23         right: 0;
 24         bottom: 0;
 25         left: 0;
 26         color: #A0A0A0;
 27         content: '';
 28         box-sizing: border-box;
 29         margin: -10px;
 30         z-index: -1;
 31     }
 32     .content:before
 33     {
 34         /*background: #cc1234;*/
 35         box-shadow: inset 0 0 0 1px;
 36         animation: ClipBefore 4s linear infinite;
 37     }
 38     .content:after
 39     {
 40         box-shadow: inset 0 0 0 2px;
 41         animation: ClipAfter 4s linear infinite;
 42         /*由于图片展示的区域比外边框小,所以这里要重新定位after的展示位置*/
 43         top: 18px;
 44         bottom: 0px;
 45         right: 0px;
 46         left: 18px;
 47     }
 48     .content>img
 49     {
 50         width: 300px;
 51         height: 200px;
 52     }
 53 
 54     @keyframes ClipAfter {
 55         0%, 100% {
 56             clip: rect(0px,302px,202px,0px);
 57         }
 58         25% {
 59             clip: rect(100px,302px,202px,150px);
 60         }
 61 
 62         50% {
 63             clip: rect(200px,302px,202px,300px);
 64         }
 65         75% {
 66             clip: rect(100px,302px,202px,150px);
 67         }
 68     }
 69     @keyframes ClipBefore {
 70         100%,0%{
 71             clip:rect(0px,300px,200px,0px);
 72         }
 73         25%
 74         {
 75             clip:rect(0px,150px,100px,0px);
 76         }
 77         50%{
 78             clip:rect(0px,0px,0px,0px);
 79         }
 80         75%{
 81             clip:rect(0px,150px,100px,0px);
 82         }
 83     }
 84     @keyframes ClipAfter {
 85         0%, 100% {
 86             /*为了在动画过程中能保留右边框和下边框,rect的right和bottom分别多取两个像素*/
 87             /*重新定位后,为了在动画的终点和起点不要显示上边框和左边框,rect的top和left分别多取了二个像素*/
 88             clip: rect(2px,302px,202px,2px);
 89         }
 90         25% {
 91             clip: rect(100px,302px,202px,150px);
 92         }
 93 
 94         50% {
 95             clip: rect(200px,302px,202px,300px);
 96         }
 97         75% {
 98             clip: rect(100px,302px,202px,150px);
 99         }
100     }

html:

1 <div class="region-wrap">
2     <div class="region">
3         <div class="content">
4             <img src="./images/show-window/timg.jpg"/>
5         </div>
6     </div>
7 </div>

效果如下:

最后,利用flex布局,放入以列表的形式展示,并将样式应用到hover伪类中

html

 1 <div class="showwindow-wrap">
 2     <div class="showwindow">
 3         <ul class="li-items">
 4             <li>
 5                 <div class="region-wrap">
 6                     <div class="region">
 7                         <div class="content">
 8                             <img src="./images/show-window/timg1.jpg"/>
 9                         </div>
10                     </div>
11                 </div>
12             </li>
13             <li>
14                 <div class="region-wrap">
15                     <div class="region">
16                         <div class="content">
17                             <img src="./images/show-window/timg1.jpg"/>
18                         </div>
19                     </div>
20                 </div>
21             </li>
22             <li>
23                 <div class="region-wrap">
24                     <div class="region">
25                         <div class="content">
26                             <img src="./images/show-window/timg1.jpg"/>
27                         </div>
28                     </div>
29                 </div>
30             </li>
31             <li>
32                 <div class="region-wrap">
33                     <div class="region">
34                         <div class="content">
35                             <img src="./images/show-window/timg.jpg"/>
36                         </div>
37                     </div>
38                 </div>
39             </li>
40             <li>
41                 <div class="region-wrap">
42                     <div class="region">
43                         <div class="content">
44                             <img src="./images/show-window/timg.jpg"/>
45                         </div>
46                     </div>
47                 </div>
48             </li>
49             <li>
50                 <div class="region-wrap">
51                     <div class="region">
52                         <div class="content">
53                             <img src="./images/show-window/timg.jpg"/>
54                         </div>
55                     </div>
56                 </div>
57             </li>
58         </ul>
59     </div>
60 </div>

css

.showwindow-wrap
    {
        width: 100%;
        display:flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
    }
    .showwindow
    {
        width:1200px;
        flex: 1;
        background: #f4f4f4;
    }
    .li-items
    {
        margin: 0px;
        padding: 0px;
        display:flex;
        flex-direction: row;
        align-items: flex-start;
        flex-wrap: wrap;
        justify-content: center;
    }
    .li-items>li
    {
        float: left;
        width: 323px;
        height: 222px;
        overflow: hidden;
        margin-left: -2px;
        margin-top: -1px;
    }
    .region-wrap {
        width: 320px;
        height: 220px;
        border: 1px solid #f4f4f4;
    }

    .region {
        position: absolute;
    }
    .content
    {
        position:  absolute;
        top: 10px;
        left: 10px;
        width: 300px;
        height: 200px;
        /*border:1px solid #aa0507;*/
    }
    .content:before,.content:after
    {
        position: absolute;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;
        color: #ea0c0c;
        content: '';
        box-sizing: border-box;
        margin: -10px;
        z-index: 10;
    }
    .content:hover
    {
        cursor: pointer;
    }
    .content:hover:before
    {
        top: -1px;
        right: 0;
        bottom: 0;
        left: -1px;
        box-shadow: inset 0 0 0 1px;
        animation: ClipBefore 4s linear infinite;
    }
    .content:hover:after
    {
        box-shadow: inset 0 0 0 1px;
        animation: ClipAfter 4s linear infinite;
        /*由于图片展示的区域比外边框小,所以这里要重新定位after的展示位置*/
        top: 18px;
        bottom: 0px;
        right: 0px;
        left: 18px;
    }
    .content>img
    {
        width: 300px;
        height: 200px;
    }

    @keyframes ClipAfter {
        0%, 100% {
            clip: rect(0px,302px,202px,0px);
        }
        25% {
            clip: rect(100px,302px,202px,150px);
        }

        50% {
            clip: rect(200px,302px,202px,300px);
        }
        75% {
            clip: rect(100px,302px,202px,150px);
        }
    }
    @keyframes ClipBefore {
        100%,0%{
            clip:rect(0px,300px,200px,0px);
        }
        25%
        {
            clip:rect(0px,150px,100px,0px);
        }
        50%{
            clip:rect(0px,0px,0px,0px);
        }
        75%{
            clip:rect(0px,150px,100px,0px);
        }
    }
    @keyframes ClipAfter {
        0%, 100% {
            /*为了在动画过程中能保留右边框和下边框,rect的right和bottom分别多取两个像素*/
            /*重新定位后,为了在动画的终点和起点不要显示上边框和左边框,rect的top和left分别多取了二个像素*/
            clip: rect(2px,302px,202px,2px);
        }
        25% {
            clip: rect(100px,302px,202px,150px);
        }

        50% {
            clip: rect(200px,302px,202px,300px);
        }
        75% {
            clip: rect(100px,302px,202px,150px);
        }
    }
    *{
        font-size:12px;
        list-style: none;
        color: rgba(146, 248, 206, 0.91);
    }

效果如开篇所发.

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原文地址：https://www.cnblogs.com/andayhou/p/9385359.html