有趣的css - 动态雷达扫描

大家好，我是 Just，这里是「设计师工作日常」，今天分享的是使用 css 实现一个动态的雷达扫描，快学起来吧！

《有趣的css》系列最新实例通过公众号「设计师工作日常」发布。

整体效果

知识点：
① animation 动画属性中 animation-direction 以及 steps() 参数的使用

思路：先绘制出整体大圆，然后使用创建伪元素画出内里的小圆，并加上虚线边框；然后绘制出雷达层，加上动画旋转；再给雷达内增加几个闪烁的圆点；最后外层套一个小动画边框。

核心代码部分，简要说明了写法思路；完整代码在最后，可直接复制到本地运行。

核心代码

html 代码

<div class="leidabox50"></div>
<div class="leida50"><div class="line50"></div><div class="guangdian50"><span class="dian50"></span></div>
</div>

雷达的主体。

css 部分代码

.leidabox50{width:220px;height:220px;border:4px solid rgba(0,0,0,0);border-top-color: #33B589;border-bottom-color: #33B589;border-radius:50%;position: absolute;animation:leidabox-eff-50 10s linear infinite;animation-direction:reverse;
}
@keyframes leidabox-eff-50{to{transform:rotate(360deg);}
}
.leida50{width: 200px;height: 200px;display: flex;justify-content: center;align-items: center;position: relative;background-color: #31FFBA;border-radius: 50%;border: 1px solid #33B589;
}
.leida50:before,.leida50:after{content: '';width: 120px;height: 120px;border-radius: 50%;border: 1px dashed rgba(0,0,0,0.14);box-shadow: 0 0 20px rgba(0,0,0,0.1);position: absolute;z-index: 3;
}
.leida50:after{width: 60px;height: 60px;position: absolute;z-index: 10;
}
.line50{width: 100px;height: 100px;background-color: rgba(127,255,212,0.4);border-radius: 0 0 0 100%;position: absolute;left: 0;top: 100px;z-index: 100;animation: zhuaneff50 5s linear infinite;transform-origin: 100px 0;
}
.line50:after{content: '';width: 8px;height: 8px;background-color: rgba(255,255,255,0.6);position: absolute;top: -4px;right: -4px;border-radius: 50%;
}
@keyframes zhuaneff50{to {transform: rotate(360deg);}
}
.guangdian50{position: absolute;bottom: 66px;
}
.dian50,.dian50:after,.dian50:before{width: 7px;height: 7px;background-color: #33B589;position: absolute;left: -20px;border-radius: 50%;animation: eff50 5s steps(6) infinite;z-index: 999;
}
.dian50:after{content: '';width: 6px;height: 6px;top: 12px;left: 44px;
}
.dian50:before{content: '';width: 3px;height: 3px;top: 40px;left: 34px;
}
@keyframes eff50{0% {opacity: 0;transform: translate(0, 0);}25%{opacity: 1;transform: translate(-10px, -18px);}50%{opacity: 0;transform: translate(-18px, -20px);}75%{opacity: 1;transform: translate(-24px, -18px);}100%{opacity: 0;transform: translate(-34px, -24px);}
}
.guangdian50:after,.guangdian50:before{content: '';width: 6px;height: 6px;background-color: #33B589;position: absolute;top: -100px;left: 30px;border-radius: 50%;z-index: 900;animation: eff501 5s steps(6) both infinite;
}
.guangdian50:before{width: 7px;height: 7px;top: -20px;left: 40px;
}
@keyframes eff501{0% {opacity: 0;}25%{opacity: 1;}50%{opacity: 0;}75%{opacity: 1;}100%{opacity: 0;}
}

1、.leida50 画出最大的雷达圆形主体，然后通过 .leida50:before 和 .leida50:after 伪元素创建里面的两个小圆，并给两个小圆加上一点阴影效果。

2、.line50 绘制一个矩形，并给它的一个角加上圆角 border-radius: 0 0 0 100%; ，并通过 transform-origin 定位其原点，加上动画旋转，雷达就开始旋转扫描了；然后
利用 .line50:after 伪元素给中心加上一个固定点，这样整体的雷达扫描区就完成了。

3、再在雷达主体上绘制几个移动的点，利用 .dian50 、.dian50:after 和 .dian50:before 绘制 3 个大小不一的圆点，并且定位到不同的位置，然后通过加上 animation 动画，设置 steps() 参数，使这 3 个点边闪烁边移动。

4、然后再加上两个固定的圆点，同样加上 animation 动画，设置 steps() 参数，让这 2 个圆点同前面的 3 个圆点同时闪烁。

5、在外层用 .leidabox50 绘制出两个半边框，加上 animation 动画，并设置 animation-direction 参数，使反向旋转。

完整代码如下

html 页面

<!DOCTYPE html>
<html lang="zh"><head><meta charset="utf-8"><link rel="stylesheet" href="style.css"><title>动态雷达扫描</title></head><body><div class="app"><div class="leidabox50"></div><div class="leida50"><div class="line50"></div><div class="guangdian50"><span class="dian50"></span></div></div></div></body>
</html>

css 样式

/** style.css **/
.app{width: 100%;height: 100vh;background-color: #ffffff;position: relative;display: flex;justify-content: center;align-items: center;
}
.leidabox50{width:220px;height:220px;border:4px solid rgba(0,0,0,0);border-top-color: #33B589;border-bottom-color: #33B589;border-radius:50%;position: absolute;animation:leidabox-eff-50 10s linear infinite;animation-direction:reverse;
}
@keyframes leidabox-eff-50{to{transform:rotate(360deg);}
}
.leida50{width: 200px;height: 200px;display: flex;justify-content: center;align-items: center;position: relative;background-color: #31FFBA;border-radius: 50%;border: 1px solid #33B589;
}
.leida50:before,.leida50:after{content: '';width: 120px;height: 120px;border-radius: 50%;border: 1px dashed rgba(0,0,0,0.14);box-shadow: 0 0 20px rgba(0,0,0,0.1);position: absolute;z-index: 3;
}
.leida50:after{width: 60px;height: 60px;position: absolute;z-index: 10;
}
.line50{width: 100px;height: 100px;background-color: rgba(127,255,212,0.4);border-radius: 0 0 0 100%;position: absolute;left: 0;top: 100px;z-index: 100;animation: zhuaneff50 5s linear infinite;transform-origin: 100px 0;
}
.line50:after{content: '';width: 8px;height: 8px;background-color: rgba(255,255,255,0.6);position: absolute;top: -4px;right: -4px;border-radius: 50%;
}
@keyframes zhuaneff50{to {transform: rotate(360deg);}
}
.guangdian50{position: absolute;bottom: 66px;
}
.dian50,.dian50:after,.dian50:before{width: 7px;height: 7px;background-color: #33B589;position: absolute;left: -20px;border-radius: 50%;animation: eff50 5s steps(6) infinite;z-index: 999;
}
.dian50:after{content: '';width: 6px;height: 6px;top: 12px;left: 44px;
}
.dian50:before{content: '';width: 3px;height: 3px;top: 40px;left: 34px;
}
@keyframes eff50{0% {opacity: 0;transform: translate(0, 0);}25%{opacity: 1;transform: translate(-10px, -18px);}50%{opacity: 0;transform: translate(-18px, -20px);}75%{opacity: 1;transform: translate(-24px, -18px);}100%{opacity: 0;transform: translate(-34px, -24px);}
}
.guangdian50:after,.guangdian50:before{content: '';width: 6px;height: 6px;background-color: #33B589;position: absolute;top: -100px;left: 30px;border-radius: 50%;z-index: 900;animation: eff501 5s steps(6) both infinite;
}
.guangdian50:before{width: 7px;height: 7px;top: -20px;left: 40px;
}
@keyframes eff501{0% {opacity: 0;}25%{opacity: 1;}50%{opacity: 0;}75%{opacity: 1;}100%{opacity: 0;}
}