animation - 创建具有透明背景的 SVG 动画虚线

Question

我已经研究了好几个小时并试图想出一个解决方案。

在这个... https://jsfiddle.net/WebFlair/nc0zyjdq/78/

<div class="bg">

<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
 width="400.000000pt" height="400.000000pt" viewBox="0 0 400.000000 400.000000"
 preserveAspectRatio="xMidYMid meet">
<path class="path" fill="none" stroke="#b0225e" stroke-linejoin="round" stroke-width="5" stroke-miterlimit="10" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>

<path class="dashed" fill="none" stroke="white"  stroke-width="7" stroke-linejoin="round" stroke-miterlimit="16" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>
</svg>
</div>
<style>
.bg {background:#eee;}
.dashed{
  stroke-dasharray: 14;
}
.path {
  stroke-dasharray: 1000;
  stroke-dashoffset: 1000;
  animation: dash 5s linear alternate forwards;
}

@keyframes dash {
  from {
    stroke-dashoffset: 1000;
  }
  to {
    stroke-dashoffset: 0;
  }
}
</style>

您将看到灰色背景和动画的白色和粉红色虚线。

现在我知道这在我的示例中不起作用，但我想做的是使白色部分透明，以便它可以在任何背景上使用，保留动画和粉红色虚线。

谁能想出办法实现这一点？我已经遍历了所有我能想到的东西，并且总是需要白色部分来保持动画效果。

Answer 1

but what I am trying to do is make the white part transparent so thatit can be used on any background, keep the animation and the pinkdashed line.

思路如下:使用三层

1. 第一个底层会有一条白色的路径
2. 中间层将有完全相同的粉红色路径
3. 顶层会有一个 mask 路径，会逐渐揭示粉红色的路径

当“stroke: white”显示其下方的粉红色路径部分时，这将使用 mask 的属性

并且由于遮蔽路径的长度从零变为最大值(stroke-dashoffset从最大值917减小到零)，粉红色的增长路径变得可见

@keyframes dash {
  from {
    stroke-dashoffset: 917;
  }
  to {
    stroke-dashoffset: 0;
  }

说明最大路径长度为 917px

1.第一个底层会有白色路径

.bg {background:#eee;}
#dashed  {
  stroke-dasharray: 14;
  fill:none;
  stroke:white;
  stroke-width:7;
  stroke-linejoin:round; 
 
}

<div class="bg">

<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
 width="400.000000pt" height="400.000000pt" viewBox="0 0 400.000000 400.000000"
 preserveAspectRatio="xMidYMid meet">

   <!-- Bottom layer dashed white line -->
<path id="dashed" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>  
    
    
</svg>
</div>
<script>
  console.log(dashed.getTotalLength());
</script>

2.中间层会有完全一样的粉色路径

 <style>
.bg {background:#eee;}
#dashed  {
  stroke-dasharray: 14;
  fill:none;
  stroke:white;
  stroke-width:7;
  stroke-linejoin:round; 
 
} 

#pink {
stroke-dasharray: 14;
  fill:none;
  stroke:#b0225e;
  stroke-width:7;
  stroke-linejoin:round; 
  mask:url(#msk);
} 

<div class="bg">

<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
 width="400.000000pt" height="400.000000pt" viewBox="0 0 400.000000 400.000000"
 preserveAspectRatio="xMidYMid meet">


   <!-- Bottom layer dashed white line -->
<path id="dashed" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>  
      <!-- Middle layer dashed pink line -->
     <path id="pink" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>

</svg>
</div>

3.顶层会有遮蔽路径，逐渐显露粉色路径

.bg {background:#eee;}
#dashed  {
  stroke-dasharray: 14;
  fill:none;
  stroke:white;
  stroke-width:7;
  stroke-linejoin:round; 
 
} 

#pink {
stroke-dasharray: 14;
  fill:none;
  stroke:#b0225e;
  stroke-width:7;
  stroke-linejoin:round; 
  mask:url(#msk);
} 

#maskLine {
  fill:none;
  stroke:white;
  stroke-width:7;
  stroke-dasharray: 917;
  stroke-dashoffset: 917;
  animation: dash 5s linear alternate forwards;
}

@keyframes dash {
  from {
    stroke-dashoffset: 917;
  }
  to {
    stroke-dashoffset: 0;
  }
}

<div class="bg">

<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
 width="400.000000pt" height="400.000000pt" viewBox="0 0 400.000000 400.000000"
 preserveAspectRatio="xMidYMid meet">
<defs>
  <mask id="msk">  
       <!-- A mask layer that reveals a dashed pink line -->
    <path id="maskLine"  d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>  
  </mask>
</defs>

   <!-- Bottom layer dashed white line -->
<path id="dashed" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>  
      <!-- Middle layer dashed pink line -->
     <path id="pink" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>
    
</svg>
</div>

更新

在重复点击“播放”按钮时填充、清除路径

var dash = true;

function play() {
  var path = document.getElementById('maskLine');
  path.style.strokeDashoffset = (dash) ? '0' : '917.00';
  dash = !dash;
} 

.bg {background:#eee;}
#dashed  {
  stroke-dasharray: 14;
  fill:none;
  stroke:white;
  stroke-width:7;
  stroke-linejoin:round; 
 
} 

#pink {
stroke-dasharray: 14;
  fill:none;
  stroke:#b0225e;
  stroke-width:7;
  stroke-linejoin:round; 
  mask:url(#msk);
} 

#maskLine {
  fill:none;
  stroke:white;
  stroke-width:7;
  stroke-dasharray: 917;
  stroke-dashoffset: 917;
  transition: stroke-dashoffset 5s linear;
}

<button onclick="play();">Play</button>
<div class="bg">

<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
 width="400.000000pt" height="400.000000pt" viewBox="0 0 400.000000 400.000000"
 preserveAspectRatio="xMidYMid meet">
<defs>
  <mask id="msk">  
       <!-- A mask layer that reveals a dashed pink line -->
    <path id="maskLine"  d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591">
     </path>
        
     </path>    
  </mask>
</defs>

   <!-- Bottom layer dashed white line -->
<path id="dashed" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>  
      <!-- Middle layer dashed pink line -->
     <path id="pink" d="M23.742,10.709
    c-2.305,23.611-8.81,46.563-9.021,70.829c-0.252,28.966,22.237,43.666,47.06,55.482c23.642,11.255,42.368,15.766,68.461,16.631
    c19.993,0.663,40.08,2.97,59.853-1.723c23.301-5.531,45.542-17.598,66.978-27.933c19.248-9.281,38.831-21.86,41.946-45.201
    c5.539-41.51-54.993-47.073-81.885-42.17C159.05,47.212,89.37,104.633,77.387,164.629c-5.896,29.522-4.312,60.884,12.703,86.354
    c19.17,28.697,49.512,49.927,78.596,67.591"/>

</svg>
</div>