带过滤器的新伪元素转换

Question

我正在研究图像的发光效果。为了使发光不止一种颜色，我实际上是在应用模糊和饱和度滤镜的情况下制作图像的伪元素副本。这个伪元素是通过在图像的 div.

中添加 class 创建的

现在一切都很好，但是我想用缓出来过渡发光效果，但是无论我把过渡属性放在哪里，我似乎都无法让它工作.

我做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

可能会考虑使用 animation 而不是 transition。请参阅下面的工作片段。

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>

Answer 2

当您删除 class .mask 时，伪元素 ::after 将从 DOM 中删除。您需要始终将 ::after 保持在 DOM 中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>

带过滤器的新伪元素转换

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