SVG路径覆盖和动画输出另一个路径

Question

我有一个灰色虚线的SVG。我想做的是将其覆盖在绿色SVG虚线的顶部，并将灰色动画化以显示绿色。有点像一个从右向左移动的仪表。

我看到了这个如何制作虚线的例子：

http://jsfiddle.net/ehan4/2/

能够做到，但我的底线已经破灭了。

我最终做了这个：

<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 0 666.9 123.8" enable-background="new 0 0 666.9 123.8" xml:space="preserve">
<path  opacity="0.4" stroke-width="3" fill="none" stroke="#66CD00" stroke-linecap="round" stroke-miterlimit="5" stroke-dasharray="1,6" d="
M656.2,118.5c0,0-320.4-251-645.9-0.7" />
<path id="top"  opacity="0.4" fill="none" stroke="#AEAEAE" stroke-linecap="round" stroke-miterlimit="5" stroke-dasharray="1,6" d="
M656.2,118.5c0,0-320.4-251-645.9-0.7"/>
</svg>
var path = document.querySelector('#top');
var length = path.getTotalLength();
// Clear any previous transition
path.style.transition = path.style.WebkitTransition =
'none';
// Set up the starting positions
path.style.strokeDasharray = 1  + ' ' + 6;
path.style.strokeDashoffset = length;
// Trigger a layout so styles are calculated & the browser
// picks up the starting position before animating
path.getBoundingClientRect();
// Define our transition
path.style.transition = path.style.WebkitTransition =
'stroke-dashoffset 20s linear';
// Go!
path.style.strokeDashoffset = '0';

https://jsfiddle.net/ps5yLyab/

如何覆盖两条虚线并设置灰色动画？

Answer 1

您可以使用剪辑路径来完成此操作。

首先，我们向SVG添加一个clipPath。

<defs>
<clipPath id="myclip">
<rect id="cliprect" x="100%" y="0%" width="100%" height="100%"/>
</clipPath>
</defs>

此剪辑路径的大小与SVG的大小相同(宽度和高度100%)，并从其x位置开始，位于SVG的在最右边(100%)。因此，一开始它并没有透露任何信息。

然后每10mS，我们将其x坐标降低1%(即100%->99%->98%等)。直到它达到零。

var cliprect = document.getElementById("cliprect");
var offsetX = 100;
var speed = 10;
function clipAdjust()
{
cliprect.setAttribute("x", offsetX+"%");
offsetX -= 1;
if (offsetX >= 0) {
window.setTimeout(clipAdjust, speed);
}
}
window.setTimeout(clipAdjust, speed);

下面的工作演示：

var path = document.querySelector('#top');
		var length = path.getTotalLength();
		// Clear any previous transition
		path.style.transition = path.style.WebkitTransition =
		  'none';
		// Set up the starting positions
		path.style.strokeDasharray = 1  + ' ' + 6;
		path.style.strokeDashoffset = length;
		// Trigger a layout so styles are calculated & the browser
		// picks up the starting position before animating
		path.getBoundingClientRect();
		// Define our transition
		path.style.transition = path.style.WebkitTransition =
		  'stroke-dashoffset 20s linear';
		// Go!
		path.style.strokeDashoffset = '0';
var cliprect = document.getElementById("cliprect");
var offsetX = 100;
var speed = 10;
function clipAdjust()
{
cliprect.setAttribute("x", offsetX+"%");
offsetX -= 1;
if (offsetX >= 0) {
window.setTimeout(clipAdjust, speed);
}
}
window.setTimeout(clipAdjust, speed);

<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 0 666.9 123.8" enable-background="new 0 0 666.9 123.8" xml:space="preserve">
<defs>
<clipPath id="myclip">
<rect id="cliprect" x="100%" y="0%" width="100%" height="100%"/>
</clipPath>
</defs>
<path opacity="0.4" fill="none" stroke="#AEAEAE" stroke-linecap="round"
stroke-miterlimit="5" stroke-dasharray="1,6" stroke-width="2"
d="M656.2,118.5c0,0-320.4-251-645.9-0.7"/>
<g clip-path="url(#myclip)">
<path stroke-width="3" fill="none" stroke="white"
stroke-linecap="round" stroke-miterlimit="5"
d="M656.2,118.5c0,0-320.4-251-645.9-0.7" />
<path id="top"  opacity="0.4" stroke-width="3" fill="none" stroke="#66CD00"
stroke-linecap="round" stroke-miterlimit="5" stroke-dasharray="6,6"
d="M656.2,118.5c0,0-320.4-251-645.9-0.7" />
</g>

</svg>