使用 CSS 对 SVG 进行动画处理：首先是描边，然后是填充

Question

我对使用 CSS 制作 SVG 动画完全陌生（根据我一直在阅读的内容，可能还需要 JS 来获取总路径长度）并且需要实现以下效果：http : //gph.is/2iZZ3Hw

<?xml version="1.0" encoding="utf-8"?>
<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
 viewBox="0 0 47.4 47.7" style="enable-background:new 0 0 47.4 47.7;" xml:space="preserve">
<style type="text/css">
    .st0{fill-rule:evenodd;clip-rule:evenodd;fill:none;stroke:#FEC558;stroke-width:0.5;stroke-miterlimit:22.9256;}
    .st1{fill:#FFC656;}
</style>
<path class="st0" d="M23.7,45.8c12.1,0,22-9.9,22-22c0-12.1-9.9-22-22-22c-12.1,0-22,9.9-22,22C1.7,35.9,11.6,45.8,23.7,45.8z"/>
    <g>
        <polygon class="st1" points="14.1,17.9 14.1,20.2 14.1,22.2 14.1,23.4 14.1,24.7 14.1,27.6 32.7,35.2 32.7,32.5 32.7,30.7 
    32.7,29.7 32.7,28.5 32.7,25.2   "/>
        <polygon class="st1" points="19.2,18.7 24.3,20.6 27.5,21.9 27.5,21.2 27.5,19.4 27.5,17.5 27.5,16.3 27.5,15.2 27.5,12.5 
    15.5,17.2 19.2,18.7     "/>
    </g>
</svg>

Answer 1

SVG动画

<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
width="30%" height="30%" viewBox="0 0 47.4 47.7" style="enable-background:new 0 0 47.4 47.7;" xml:space="preserve">
<style type="text/css">
    .st0{fill-rule:evenodd;clip-rule:evenodd;fill:none;stroke:#FEC558;stroke-width:0.5;stroke-miterlimit:22.9256;}
    .st1{fill:#FFC656;}
</style>
<defs>
<linearGradient id="grad" x1="0%" y1="0%" x2="0%" y2="100%" >
         
            <stop offset="0%" stop-color="#33363D"/>
            <stop offset="100%" stop-color="#5B5D5A"/>
</lineargradient>
</defs> 
<rect width="100%" height="100%" fill="url(#grad)"/>

<path id="circle" class="st0" stroke-dashoffset="138" stroke-dasharray="138" d="M23.7,45.8c12.1,0,22-9.9,22-22c0-12.1-9.9-22-22-22c-12.1,0-22,9.9-22,22C1.7,35.9,11.6,45.8,23.7,45.8z">
<animate id="an_circle" attributeName="stroke-dashoffset" values="138;0" dur="2s" fill="freeze" />
</path>
    <g stroke-width="0.5">
       <path id="trap" class="st1" stroke-dashoffset="60" stroke-dasharray="60" style="fill:none; stroke:#FEC558;" d="M14.1,17.9 14.1,20.2 14.1,22.2 14.1,23.4 14.1,24.7 14.1,27.6 32.7,35.2 32.7,32.5 32.7,30.7  32.7,29.7 32.7,28.5 32.7,25.2z">
        <animate id="an_trap" attributeName="stroke-dashoffset" values="60;0" dur="1s" fill="freeze" />
        <animate id="fill_trap" attributeName="fill" values="#33363D;#FEC558"  begin="an_circle.end" dur="1s" fill="freeze" />
     </path>
        <path id="triangle" class="st1" stroke-dashoffset="35" stroke-dasharray="35" style="fill:none; stroke:#FEC558;"  d="M19.2,18.7 24.3,20.6 27.5,21.9 27.5,21.2 27.5,19.4 27.5,17.5 27.5,16.3 27.5,15.2 27.5,12.5 15.5,17.2 19.2,18.7">
        
        <animate id="an_triangle" attributeName="stroke-dashoffset" begin="an_trap.end" values="35;0" dur="1s" fill="freeze" />
          <animate id="fill_triangle" attributeName="fill" values="#33363D;#FEC558"  begin="fill_trap.end-0.5s" dur="1s" fill="freeze" />
      </path>
    </g>
</svg>

• 使用JS确定对象的长度

    <script>
             function TotalLength(){
              var path = document.querySelector('#circle');
            var len = Math.round(path.getTotalLength() );
            alert("path length - " + len);
            };
      </script>

路径长度：

对于圆 - 138px

对于梯形 - 60px

对于三角形 - 35px

• 绘制对象动画的命令

<animate id="an_circle" attributeName="stroke-dashoffset"
   values="138;0" dur="2s" fill="freeze" />

  <animate id="an_trap" attributeName="stroke-dashoffset"
     values="60;0" dur="1s" fill="freeze" />

<animate id="an_triangle" attributeName="stroke-dashoffset" 
   begin="an_trap.end" values="35;0" dur="1s" fill="freeze" />

• 绘制梯形动画时开始绘制三角形动画

begin="an_trap.end"

• 当动画完成绘制一个圆时，动画填充颜色梯形将开始

<animate id="fill_trap" attributeName="fill" values="#33363D;#FEC558"  
    begin="an_circle.end" dur="1s" fill="freeze" />

• 当梯形的填充动画结束时，三角形的颜色填充动画将开始

    <animate id="fill_triangle" attributeName="fill" values="#33363D;#FEC558"  
       begin="fill_trap.end-0.5s" dur="1s" fill="freeze" />