CSS3组件化之圆波扩散

本篇文章主要介绍用CSS3实现的水波扩散涟漪，圆波扩散，光圈扩散，雷达波向外散发动画。

预期效果应该是这样：，其实应该比这个更优美，因为设计师提供的gif出现透明度丢失问题，所以建议用css3实现。

一、明确参数

1、半径

30，42，54
2、透明度

100%，50%，20%
3、颜色

#fb7070

二、实现方案

1、border-width + animation

<div parent="box">
    <a id="J_dot"></a>
</div>

div[parent="box"] {
  position: relative;
  margin:50px auto;
  width:54px;
  height: 54px;
}
#J_dot{
  float: left;
  width: 54px;
  height: 54px;
  box-sizing: border-box;
  border-style:double;
  border-color: #fb7070;
  border-radius: 100%;
  animation: circleAnimation 1s infinite alternate;
}

@keyframes circleAnimation {
  from {
     border-width:;
  }
  to {
     border-width:27px;
  }
}

@-webkit-keyframes circleAnimation {
  from {
    border-width:;
  }
  to {
    border-width:27px;
  }
}

太假了，整个动画一直固定在大圆圈内，内圆圈似乎在来回放大缩小，离期望值太远！

2、box-shadow + background-color +animation

<div parent="box">
  <div class="outer-circle">
    <div class="inner-circle"></div>
  </div>
</div>

div[parent="box"] {
  position:relative;
  margin:50px auto;
  width:54px;
  height:54px;
}
.outer-circle {
  animation: circleAnimationOut 1.5s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.inner-circle {
  animation: circleAnimationIn 1.5s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.outer-circle, .inner-circle {
  position: absolute;
  z-index:;
  width: 30px;
  height: 30px;
  background: transparent;
  border-radius: 100%;
  animation-iteration-count: infinite;
}

@keyframes circleAnimationOut {
  0% {
    box-shadow: 0 0 0 0px rgba(251, 112, 112, 0.5);
  }
  100% {
    box-shadow: 0 0 0 24px rgba(251, 112, 112, 0.2);
  }
}
@keyframes circleAnimationIn {
  0% {
    box-shadow: 0 0 0 0px rgba(251, 112, 112, 0.5);
    background-color: rgba(251, 112, 112, 1);
  }
  100% {
    box-shadow: 0 0 0 12px rgba(251, 112, 112, 0.5);
    background-color: rgba(251, 112, 112, 1);
  }
}

中间实心圆貌似没怎么动啊，效果还凑合。

3、box-shadow + transform +animation

<div parent="box">
  <div class="dot"></div>
  <div class="inner-circle"></div>
  <div class="outer-circle"></div>
</div>

@keyframes circleAnimationIn {
  0% {
    transform: scale(0.3);
    -webkit-transform: scale(0.3);
    opacity: 0.0;
  }
  25% {
    transform: scale(0.3);
    -webkit-transform: scale(0.3);
    opacity: 0.1;
  }
  50% {
    transform: scale(0.5);
    -webkit-transform: scale(0.5);
    opacity: 0.3;
  }
  75% {
    transform: scale(0.8);
    -webkit-transform: scale(0.8);
    opacity: 0.5;
  }
  100% {
    transform: scale(1);
    -webkit-transform: scale(1);
    opacity: 0.0;
  }
}
@keyframes circleAnimationOut {
  0% {
    transform: scale(0.3);
    -webkit-transform: scale(0.3);
    opacity: 0.0;
  }
  25% {
    transform: scale(0.3);
    -webkit-transform: scale(0.3);
    opacity: 0.1;
  }
  50% {
    transform: scale(0.3);
    -webkit-transform: scale(0.3);
    opacity: 0.3;
  }
  75% {
    transform: scale(0.5);
    -webkit-transform: scale(0.5);
    opacity: 0.5;
  }
  100% {
    transform: scale(0.8);
    -webkit-transform: scale(0.8);
    opacity: 0.0;
  }
}
div[parent="box"] {
  position: relative;
  margin: 50px auto;
  width: 54px;
  height: 54px;
}

/* 保持大小不变的小圆点 */
.dot {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 20px;
  height: 20px;
  margin-left: -9px;
  margin-top: -9px;
  -webkit-border-radius: 50%;
  -moz-border-radius: 50%;
  border-radius: 50%;
  background-color: #fb7070; /* 实心圆 ，如果没有这个就是一个小圆圈 */
  z-index:;
}

/* 产生动画（向外扩散变大）的圆圈 第一个圆 */
.inner-circle {
  position: absolute;
  z-index:;
  width: 54px;
  height: 54px;
  -webkit-border-radius: 50%;
  -moz-border-radius: 50%;
  border-radius: 50%;
  border: 1px solid #fb7070;
  -webkit-animation: circleAnimationIn 2s ease-out;
  -moz-animation: circleAnimationIn 2s ease-out;
  animation: circleAnimationIn 2s ease-out;
  -webkit-animation-iteration-count: infinite;
  -moz-animation-iteration-count: infinite;
  animation-iteration-count: infinite;
  box-shadow: 1px 1px 30px #fb7070;
}

/* 产生动画（向外扩散变大）的圆圈 第二个圆 */
.outer-circle {
  position: absolute;
  z-index:;
  width: 54px;
  height: 54px;
  -webkit-border-radius: 50%;
  -moz-border-radius: 50%;
  border-radius: 50%;
  border: 1px solid #fb7070;
  -webkit-animation: circleAnimationOut 2s ease-out;
  -moz-animation: circleAnimationOut 2s ease-out;
  animation: circleAnimationOut 2s ease-out;
  -webkit-animation-iteration-count: infinite;
  -moz-animation-iteration-count: infinite;
  animation-iteration-count: infinite;
  box-shadow: 1px 1px 30px #fb7070;
}