具有透明背景的 CSS pie spinner/loader

Question

我只需要使用 css 和 javascript 来制作 pie spinner/loader。

到目前为止，当背景是纯色时，我设法让它工作，因为它不需要查看隐藏半圆的 div（不介意颜色和顶部/左侧）：

.wrapper {
  position: relative;
  background: transparent;
  width: 50px;
  height: 50px;
  background: gray;
}

.wrapper,
.wrapper * {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.wrapper .pie,
.wrapper * .pie {
  width: 50%;
  height: 100%;
  transform-origin: 100% 50%;
  position: absolute;
  background: red;
}

.wrapper .spinner,
.wrapper * .spinner {
  border-radius: 100% 0 0 100%/50% 0 0 50%;
  z-index: 200;
  border-right: none;
  animation: rota 5s linear infinite
}

.wrapper .filler,
.wrapper * .filler {
  border-radius: 0 100% 100% 0/0 50% 50% 0;
  left: 50%;
  opacity: 0;
  z-index: 100;
  border-left: none;
  background: red;
  animation: opa 5s steps(1, end) infinite reverse
}

.wrapper .mask,
.wrapper * .mask {
  width: 50%;
  height: 100%;
  position: absolute;
  background: inherit;
  opacity: 1;
  z-index: 300;
  animation: opa 5s steps(1, end) infinite
}

.wrapper:hover .spinner,
.wrapper:hover .filler,
.wrapper:hover .mask {
  animation-play-state: running;
}

@-moz-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-webkit-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-o-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-moz-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@-webkit-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@-o-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

<div class="wrapper">
  <div class="pie spinner"></div>
  <div class="pie filler"></div>
  <div class="mask"></div>
</div>

问题是，我需要使背景透明，这样我才能看到它，但是蒙版 div 变得无用：

body {
  background-image: url(http://www.publicdomainpictures.net/pictures/20000/velka/tulip-flower-garden.jpg)
}

.wrapper {
  position: relative;
  background: transparent;
  width: 50px;
  height: 50px;
  background: transparent;
}

.wrapper,
.wrapper * {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.wrapper .pie,
.wrapper * .pie {
  width: 50%;
  height: 100%;
  transform-origin: 100% 50%;
  position: absolute;
  background: red;
}

.wrapper .spinner,
.wrapper * .spinner {
  border-radius: 100% 0 0 100%/50% 0 0 50%;
  z-index: 200;
  border-right: none;
  animation: rota 5s linear infinite
}

.wrapper .filler,
.wrapper * .filler {
  border-radius: 0 100% 100% 0/0 50% 50% 0;
  left: 50%;
  opacity: 0;
  z-index: 100;
  border-left: none;
  background: red;
  animation: opa 5s steps(1, end) infinite reverse
}

.wrapper .mask,
.wrapper * .mask {
  width: 50%;
  height: 100%;
  position: absolute;
  background: inherit;
  opacity: 1;
  z-index: 300;
  animation: opa 5s steps(1, end) infinite
}

.wrapper:hover .spinner,
.wrapper:hover .filler,
.wrapper:hover .mask {
  animation-play-state: running;
}

@-moz-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-webkit-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-o-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-moz-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@-webkit-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@-o-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

<div class="wrapper">
  <div class="pie spinner"></div>
  <div class="pie filler"></div>
  <div class="mask"></div>
</div>

有没有可能实现我想要的？怎么样？

Answer 1

.wrapper {
  position: relative;
  background: transparent !important; 
  width: 50px;
  height: 50px;
  background: gray;
}

.wrapper,
.wrapper * {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.wrapper .pie,
.wrapper * .pie {
  width: 50%;
  height: 100%;
  transform-origin: 100% 50%;
  position: absolute;
  background: red;
}

.wrapper .spinner,
.wrapper * .spinner {
  border-radius: 100% 0 0 100%/50% 0 0 50%;
  z-index: 200;
  border-right: none;
  animation: rota 5s linear infinite
}

.wrapper .filler,
.wrapper * .filler {
  border-radius: 0 100% 100% 0/0 50% 50% 0;
  left: 50%;
  opacity: 0;
  z-index: 100;
  border-left: none;
  background: red;
  animation: opa 5s steps(1, end) infinite reverse
}

.wrapper .mask,
.wrapper * .mask {
  width: 50%;
  height: 100%;
  position: absolute;
  background: inherit;
  opacity: 1;
  z-index: 300;
  animation: opa 5s steps(1, end) infinite
}

.wrapper:hover .spinner,
.wrapper:hover .filler,
.wrapper:hover .mask {
  animation-play-state: running;
}

@-moz-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-webkit-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-o-keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@keyframes rota {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@-moz-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@-webkit-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@-o-keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

@keyframes opa {
  0% {
    opacity: 1;
  }
  50%,
  100% {
    opacity: 0;
  }
}

<div class="wrapper">
  <div class="pie spinner"></div>
  <div class="pie filler"></div>
  <div class="mask"></div>
</div>

添加背景透明重要

.wrapper { background: transparent !important; }

Answer 2

您可以使用 javascript 为您的加载器设置计时器...这是一个简单的示例

$(document).ready(function() {

setTimeout(function(){
    $('body').addClass('pie spinner');
}, 3000); });