iOS 上的动画笔触虚线偏移量

Question

所以，我通过增加stroke-dashoffset值来动画这个SVG徽标

svg {
position: absolute; top: 50%; left: 50%;
transform: translateX(-50%) translateY(-50%);
width: 150px;
}
.cls-1,
.cls-2 {
fill:none;
stroke:#a9a9a9;
stroke-linecap:round;
stroke-linejoin:round;
stroke-width:10px;
}
.cls-1 {
stroke-dasharray: 496;
stroke-dashoffset: -496;
animation: firstLine 2s ease-out 0s infinite normal;
}
.cls-2 {
stroke-dasharray: 458;
stroke-dashoffset: -458;
animation: secondLine 2s ease-out 0s infinite normal;
}
@keyframes firstLine {
0% { stroke-dashoffset: -496; }
40% { stroke-dashoffset: 0; }
60% { stroke-dashoffset: 0; }
85% { stroke-dashoffset: 496; }
100% { stroke-dashoffset: 496; }
}
@keyframes secondLine {
0% { stroke-dashoffset: -458; }
45% { stroke-dashoffset: 0; }
60% { stroke-dashoffset: 0; }
90% { stroke-dashoffset: 458; }
100% { stroke-dashoffset: 458; }
}

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200.17 135"><path class="cls-1" d="M132.67,28.44a39.06,39.06,0,0,1,0,78.12H113.22V59.11A54.11,54.11,0,0,0,5,59.11v57.35a13.54,13.54,0,0,0,27.08,0v-9.9h27"/><path class="cls-2" d="M113.63,5h19a62.5,62.5,0,0,1,0,125H102.44a16.29,16.29,0,0,1-16.3-16.29V59.11a27,27,0,0,0-54.06,0V79.89h27"/></svg>

在桌面浏览器上打开时，一切都很好。安卓也是如此。但是在iOS上，动画是如此错误。是否有一些我不知道的iOS特定错误stroke-dashoffset？

Answer 1

长期以来，我一直在寻找一种解决方案，如何将负笔划线偏移量值替换为正值，以规避野生动物园施加的限制。

给出了对一行进行动画处理的解释。对于第二行，计算类似。

• 直线的总长度是496 px;因此， stroke-dashoffset = "496"的值完全隐藏了这条线。
• 使用双值绘制stroke-dashoffset ="992"线
• 三重值stroke-dashoffset =" 1488 "，线条被擦除 再

CSS解决方案

svg {
position: absolute; top: 50%; left: 50%;
transform: translateX(-50%) translateY(-50%);
width: 150px;
}
.cls-1,
.cls-2 {
fill:none;
stroke:#a9a9a9;
stroke-linecap:round;
stroke-linejoin:round;
stroke-width:10px;
}
.cls-1 {
stroke-dasharray: 496;
stroke-dashoffset: 0;
animation: firstLine 2s ease-out 0s infinite normal;
}
.cls-2 {
stroke-dasharray: 458;
stroke-dashoffset: 0;
animation: secondLine 2s ease-out 0s infinite normal;
}
@keyframes firstLine {
0% { stroke-dashoffset: 496; }
40% { stroke-dashoffset: 992; }
60% { stroke-dashoffset: 992; }
85% { stroke-dashoffset: 1488; }
100% { stroke-dashoffset: 1488; }
}
@keyframes secondLine {
0% { stroke-dashoffset: 458; }
45% { stroke-dashoffset: 916; }
60% { stroke-dashoffset: 916; }
90% { stroke-dashoffset: 1374; }
100% { stroke-dashoffset: 1374; }
}

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200.17 135">
<path class="cls-1 " d="M132.67,28.44a39.06,39.06,0,0,1,0,78.12H113.22V59.11A54.11,54.11,0,0,0,5,59.11v57.35a13.54,13.54,0,0,0,27.08,0v-9.9h27" >
</path>
<path class="cls-2" d="M113.63,5h19a62.5,62.5,0,0,1,0,125H102.44a16.29,16.29,0,0,1-16.3-16.29V59.11a27,27,0,0,0-54.06,0V79.89h27" > 
</path>

</svg>

徽标周围有阴影的选项

添加阴影

<defs>
<filter id="shadow" x="-20%" y="-20%" width="200%" height="200%">
<feDropShadow dx="4" dy="8" stdDeviation="4"/>
</filter>
</defs> 

body {
background: rgb(144,210,152);
background: linear-gradient(286deg, rgba(144,210,152,1) 29%, rgba(236,234,154,1) 69%);
}
svg {
position: absolute; top: 50%; left: 50%;
transform: translateX(-50%) translateY(-50%);
width: 150px;
}
.cls-1,
.cls-2 {
fill:none;
stroke:#a9a9a9;
stroke-linecap:round;
stroke-linejoin:round;
stroke-width:10px;
filter:url(#shadow);
}
.cls-1 {
stroke-dasharray: 496;
stroke-dashoffset: 0;
animation: firstLine 4s ease-out 0s infinite normal;
}
.cls-2 {
stroke-dasharray: 458;
stroke-dashoffset: 0;
animation: secondLine 4s ease-out 0s infinite normal;
}
@keyframes firstLine {
0% { stroke-dashoffset: 496; }
40% { stroke-dashoffset: 992; }
60% { stroke-dashoffset: 992; }
85% { stroke-dashoffset: 1488; }
100% { stroke-dashoffset: 1488; }
}
@keyframes secondLine {
0% { stroke-dashoffset: 458; }
45% { stroke-dashoffset: 916; }
60% { stroke-dashoffset: 916; }
90% { stroke-dashoffset: 1374; }
100% { stroke-dashoffset: 1374; }
}

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 220.17 150">
<defs>
<filter id="shadow" x="-20%" y="-20%" width="200%" height="200%">
<feDropShadow dx="4" dy="8" stdDeviation="4"/>
</filter>
</defs> 
	
<path class="cls-1 " d="M132.67,28.44a39.06,39.06,0,0,1,0,78.12H113.22V59.11A54.11,54.11,0,0,0,5,59.11v57.35a13.54,13.54,0,0,0,27.08,0v-9.9h27" >
</path>
<path class="cls-2" d="M113.63,5h19a62.5,62.5,0,0,1,0,125H102.44a16.29,16.29,0,0,1-16.3-16.29V59.11a27,27,0,0,0-54.06,0V79.89h27" > 
</path> 
</svg>

SVG 解决方案

svg {
position: absolute; top: 50%; left: 50%;
transform: translateX(-50%) translateY(-50%);
width: 150px;
}
.cls-1,
.cls-2 {
fill:none;
stroke:#a9a9a9;
stroke-linecap:round;
stroke-linejoin:round;
stroke-width:10px;
}

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200.17 135">
<path class="cls-1 " d="M132.67,28.44a39.06,39.06,0,0,1,0,78.12H113.22V59.11A54.11,54.11,0,0,0,5,59.11v57.35a13.54,13.54,0,0,0,27.08,0v-9.9h27" stroke-dasharray="496,496" stroke-dashoffset="496">
<animate id="an_offset"
attributeName="stroke-dashoffset"
	begin="0s"
	dur="3s"
	values="496;992;992;1488"
	fill="freeze"
	repeatCount="indefinite"  />
</path>
<path class="cls-2" d="M113.63,5h19a62.5,62.5,0,0,1,0,125H102.44a16.29,16.29,0,0,1-16.3-16.29V59.11a27,27,0,0,0-54.06,0V79.89h27" stroke-dasharray="458,458" stroke-dashoffset="458"> 
<animate id="an_offset2"
	 attributeName="stroke-dashoffset"
	 begin="0s"
	 dur="3s"
	 values="458;916;916;1374"
	 fill="freeze"
	 repeatCount="indefinite" />
</path>

</svg>

其他示例
从每条线的中点绘制

若要实现动画，请更改stroke-dasharray属性的参数

总行长为496px，其中一半为248px

• 因为按顺序排列的参数值意味着：
  0 - line、248 - space0 - line、248 - space。
  因此，写stroke-dasharray = "0,248 0,248"会完全隐藏行
• 有了stroke-dasharray = "0,0 496,0"，这条线将完全可见。

svg {
position: absolute; top: 50%; left: 50%;
transform: translateX(-50%) translateY(-50%);
width: 150px;
}
.cls-1,
.cls-2 {
fill:none;
stroke:#a9a9a9;
stroke-linejoin:round;
stroke-width:10px;
}

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200.17 135">
<path class="cls-1 " d="M132.67,28.44a39.06,39.06,0,0,1,0,78.12H113.22V59.11A54.11,54.11,0,0,0,5,59.11v57.35a13.54,13.54,0,0,0,27.08,0v-9.9h27" stroke-dasharray="496,496" stroke-dashoffset="496">
<animate id="an_array"
attributeName="stroke-dasharray"
	begin="0s"
	dur="4s"
	values="0,248 0,248;0,0 496,0;0,0 496,0;0,248 0,248"
	fill="freeze"
	repeatCount="indefinite"  />
</path>
<path class="cls-2" d="M113.63,5h19a62.5,62.5,0,0,1,0,125H102.44a16.29,16.29,0,0,1-16.3-16.29V59.11a27,27,0,0,0-54.06,0V79.89h27" stroke-dasharray="458,458" stroke-dashoffset="458"> 
<animate id="an_array2"
	  attributeName="stroke-dasharray"
	  begin="0s"
	  dur="4s"
	  values="0,229 0,229;0,0 458,0;0,0 458,0;0,229 0,229"
	  fill="freeze"
	  repeatCount="indefinite" />
</path> 

Answer 2

正如@RobertLongson所提到的，这是一个 Safari 错误，其中 is 不支持负值stroke-dashiffset