javascript - 滚动线动画 - HTML,CSS,JS

Question

我正在尝试输出字母 H使用 SVG 线条动画并且我被困在一个部分，我不确定在哪里编辑/修改元素所以它输出字母 H .我想通过 SVG Drawing On Scroll 输出这个图像:

看起来有点太复杂了，我最初的尝试是修改 <path元素，但我得到了不同的意外输出。我用了 SVG Drawing On Scroll来自codepen的模板，我想修改为输出上面的图像滚动 .我想知道我是否可以获得一些帮助。有什么建议？
模板代码:

// Get a reference to the <path>
var path = document.querySelector('#star-path');

// Get length of path... ~577px in this case
var pathLength = path.getTotalLength();

// Make very long dashes (the length of the path itself)
path.style.strokeDasharray = pathLength + ' ' + pathLength;

// Offset the dashes so the it appears hidden entirely
path.style.strokeDashoffset = pathLength;

// Jake Archibald says so
// https://jakearchibald.com/2013/animated-line-drawing-svg/
path.getBoundingClientRect();

// When the page scrolls...
window.addEventListener("scroll", function(e) {
 
  // What % down is it? 
  // https://stackoverflow.com/questions/2387136/cross-browser-method-to-determine-vertical-scroll-percentage-in-javascript/2387222#2387222
  // Had to try three or four differnet methods here. Kind of a cross-browser nightmare.
  var scrollPercentage = (document.documentElement.scrollTop + document.body.scrollTop) / (document.documentElement.scrollHeight - document.documentElement.clientHeight);
    
  // Length to offset the dashes
  var drawLength = pathLength * scrollPercentage;
  
  // Draw in reverse
  path.style.strokeDashoffset = pathLength - drawLength;
    
  // When complete, remove the dash array, otherwise shape isn't quite sharp
 // Accounts for fuzzy math
  if (scrollPercentage >= 0.99) {
    path.style.strokeDasharray = "none";
    
  } else {
    path.style.strokeDasharray = pathLength + ' ' + pathLength;
  }
  
});

body {
  /* feel free to change height */
  height: 5000px;
  background: linear-gradient(
    to bottom,
    orange,
    darkblue
  );
}

h1 {
  font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif; 
  font-weight: 300;
  color: white;
  text-transform: uppercase;
  text-align: center;
  font-size: 22px;
  letter-spacing: 5px;
  font-weight: 100;
  padding: 25px 15px;
  text-shadow: 1px 1px 1px #333;
}

#star-svg {
  position: fixed;
  top: 50%;
  left: 50%;
  width: 150px;
  height: 150px;
  margin: -75px 0 0 -75px;
}



Resources

<h1>Scroll-to-draw</h1>

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100.6 107.6" id="star-svg">
  <path fill="none" stroke="white" stroke-width="2" id="star-path" d="M43.7,65.8L19.9,83.3c-2.9,1.9-5.1,3.2-7.9,3.2c-5.7,0-10.5-5.1-10.5-10.8
    c0-4.8,3.8-8.2,7.3-9.8l27.9-12L8.8,41.4c-3.8-1.6-7.3-5.1-7.3-9.8c0-5.7,5.1-10.5,10.8-10.5c2.9,0,4.8,1,7.6,3.2l23.8,17.4
    l-3.2-28.2c-1-6.7,3.5-12,9.8-12c6.3,0,10.8,5.1,9.8,11.7L57,41.8l23.8-17.4c2.9-2.2,5.1-3.2,7.9-3.2c5.7,0,10.5,4.8,10.5,10.5
    c0,5.1-3.5,8.2-7.3,9.8L63.9,53.8l27.9,12c3.8,1.6,7.3,5.1,7.3,10.1c0,5.7-5.1,10.5-10.8,10.5c-2.5,0-4.8-1.3-7.6-3.2L57,65.8
    l3.2,28.2c1,6.7-3.5,12-9.8,12c-6.3,0-10.8-5.1-9.8-11.7L43.7,65.8z"/>
</svg>

Answer 1

您需要在像 Inkscape 这样的 SVG 编辑器中跟踪您的图片.
安装 Inkscape，导入您的图片，然后使用线条或节点工具以尽可能少的点跟踪轮廓。
然后保存 SVG 并在里面查找路径。
这是我简化后得到的路径:M 0,0 V 66 H 13 V 37 H 40 V 66 H 53 V 0 H 40 V 26 H 13 V 0 Z这是带有更新路径的示例代码:

// Get a reference to the <path>
var path = document.querySelector('#star-path');

// Get length of path... ~577px in this case
var pathLength = path.getTotalLength();

// Make very long dashes (the length of the path itself)
path.style.strokeDasharray = pathLength + ' ' + pathLength;

// Offset the dashes so the it appears hidden entirely
path.style.strokeDashoffset = pathLength;

// Jake Archibald says so
// https://jakearchibald.com/2013/animated-line-drawing-svg/
path.getBoundingClientRect();

// When the page scrolls...
window.addEventListener("scroll", function(e) {
 
  // What % down is it? 
  // https://stackoverflow.com/questions/2387136/cross-browser-method-to-determine-vertical-scroll-percentage-in-javascript/2387222#2387222
  // Had to try three or four differnet methods here. Kind of a cross-browser nightmare.
  var scrollPercentage = (document.documentElement.scrollTop + document.body.scrollTop) / (document.documentElement.scrollHeight - document.documentElement.clientHeight);
    
  // Length to offset the dashes
  var drawLength = pathLength * scrollPercentage;
  
  // Draw in reverse
  path.style.strokeDashoffset = pathLength - drawLength;
    
  // When complete, remove the dash array, otherwise shape isn't quite sharp
 // Accounts for fuzzy math
  if (scrollPercentage >= 0.99) {
    path.style.strokeDasharray = "none";
    
  } else {
    path.style.strokeDasharray = pathLength + ' ' + pathLength;
  }
  
});

body {
  /* feel free to change height */
  height: 5000px;
  background: linear-gradient(
    to bottom,
    orange,
    darkblue
  );
}

h1 {
  font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif; 
  font-weight: 300;
  color: white;
  text-transform: uppercase;
  text-align: center;
  font-size: 22px;
  letter-spacing: 5px;
  font-weight: 100;
  padding: 25px 15px;
  text-shadow: 1px 1px 1px #333;
}

#star-svg {
  position: fixed;
  top: 50%;
  left: 50%;
  width: 150px;
  height: 150px;
  margin: -75px 0 0 -75px;
}



Resources

<h1>Scroll-to-draw</h1>

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 250" id="star-svg">
  <path fill="none" stroke="white" stroke-width="2" id="star-path" d="M 0,0 V 66 H 13 V 37 H 40 V 66 H 53 V 0 H 40 V 26 H 13 V 0 Z"/>
</svg>