带有过滤器的新伪元素上的转换

Question

我正在为图像制作发光效果。 为了使发光不止一种颜色，我实际上是在制作图像的伪元素副本，并应用了模糊和饱和度过滤器。这个伪元素是通过向图像的 div 添加一个类来创建的。

现在这一切都很好，但我想通过缓出来过渡发光效果，但是无论我将过渡属性放在哪里，我似乎都无法让它工作。

我制作了一个代码笔来说明： https://codepen.io/anon/pen/eYGJGPG

function addGlow() {
  document.getElementById('example').classList.toggle('mask')
}

.img {
  height: fit-content;
  width: fit-content;
  display: block;
  /* Doesn't transition */
  transition: all 0.3s ease-out;
  -webkit-transition: all 0.3s ease-out;
  -moz-transition: all 0.3s ease-out;
  -o-transition: all 0.3s ease-out;
}

.go {
  height: 400px;
  width: 400px;
  background: url("https://upload.wikimedia.org/wikipedia/commons/3/32/RGB_color_wheel_72.svg");
  background-size: initial;
}

.mask::after {
  content: "";
  width: inherit;
  height: inherit;
  position: absolute;
  background: inherit;
  background-position: center center;
  filter: blur(10px) saturate(3);
  z-index: -1;
}

<div id="example" class="img go"></div>
<button onclick="addGlow()">Press</button>

Answer 1

当您删除类 .mask 时，伪元素 ::after 将从 DOM 中删除。您需要始终在 DOM 中保留 ::after 以查看其上发生的转换：

function addGlow() {
  document.getElementById('example').classList.toggle('mask')
}

.img {
  height: fit-content;
  width: fit-content;
  display: block;
}

.go {
  height: 400px;
  width: 400px;
  background: url("https://upload.wikimedia.org/wikipedia/commons/3/32/RGB_color_wheel_72.svg");
  background-size: initial;
}

.img::after {
  content: "";
  width: inherit;
  height: inherit;
  position: absolute;
  background: inherit;
  background-position: center center;
  z-index: -1;
  
  /* initial state */
  filter: blur(0px) saturate(0);
  transition: all 1.3s ease-out;
  -webkit-transition: all 1.3s ease-out;
  -moz-transition: all 1.3s ease-out;
  -o-transition: all 1.3s ease-out;
}

.mask::after {
  /* glow */
  filter: blur(30px) saturate(3);
}

<div id="example" class="img go"></div>
<button onclick="addGlow()">Press</button>

Answer 2

可能考虑使用animation 而不是transition。请参阅下面的工作 sn-p。

function addGlow(){
  document.getElementById('example').classList.toggle('mask')
}

.img {
  height: fit-content;
  width: fit-content;
  display: block;
  /* Doesn't transition */

}

.go {
  height: 400px;
  width: 400px;
  background: url("https://upload.wikimedia.org/wikipedia/commons/3/32/RGB_color_wheel_72.svg");
  background-size: initial;

}


.mask::after {
  content: "";
  width: inherit;
  height: inherit;
  position: absolute;
  background: inherit;
  background-position: center center;
  z-index: -1;
  animation: example-animation .5s ease-out;
  animation-direction: normal;
  animation-iteration-count: 1;
  filter: blur(10px) saturate(3);
}

@keyframes example-animation {
  0% {
      filter: blur(0) saturate(3);

  }
  100% {
     filter: blur(10px) saturate(3);

  }
}

<div id="example" class="img go"></div>
<button onclick="addGlow()">Press</button>