使用clipPathUnits="objectBoundingBox“使剪辑路径消失

Question

问题：

我已经创建了一个需要响应的SVG剪辑路径，但是当我尝试在剪辑路径标记中使用clipPathUnits="objectBoundingBox"时，它会使目标对象消失。

我做了带和不带的例子片段。第一个显示为预期的，但第二个是完全隐藏的。

我用各种简单的形状和路径测试了它，它们工作得很好，但我无法让clipPathUnits="objectBoundingBox"处理任何更复杂的事情，也不确定我缺少什么。

片段：

​

body {
  background: #333;
}

#hero {
  background: url(https://source.unsplash.com/random);
  height: 120vh;
  background-color: #ff0000;
  width: 100vw;
  background-size: cover;
  clip-path: url(#wav);
}

#hero2 {
  background: url(https://source.unsplash.com/random);
  height: 120vh;
  background-color: #ff0000;
  width: 100vw;
  background-size: cover;
  clip-path: url(#wav2);
}

<div id="hero"></div>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
      <clipPath id="wav" >
        <path d="M815.8,19.7c-18.9,0-18.7,15.3-37.9,15.3-17.6,0-19.6-13-38-13-15,0-14.9,11.1-38,11.1C672.5,33.1,676,4.6,640,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18s-32.8,15.9-49.9,15.9c-13.1,0-19.7-4-26.3-9.7h0c-6.5-5.6-13.2-13-26.3-13C375.8,19.7,376,35,356.9,35c-17.6,0-19.7-13-38-13-15.1,0-14.9,11.1-38,11.1C251.5,33.1,255,4.6,219,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18S43.3,42.4,26.3,42.4c-13.1,0-19.7-4-26.3-9.7V562.6c6.5,5.6,13.2,12.9,26.2,12.9,18.9,0,18.7-15.2,37.9-15.2,17.6,0,19.6,12.9,38,12.9,15,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.8-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6h0c6.5,5.7,13.2,13,26.3,13,18.9,0,18.7-15.2,37.8-15.2,17.6,0,19.7,12.9,38,12.9,15.1,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.9-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6V32.7C835.5,27.1,828.8,19.7,815.8,19.7Z" />
      </clipPath>       
  </svg>


<div id="hero2"></div>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
      <clipPath id="wav2" clipPathUnits="objectBoundingBox">
        <path d="M815.8,19.7c-18.9,0-18.7,15.3-37.9,15.3-17.6,0-19.6-13-38-13-15,0-14.9,11.1-38,11.1C672.5,33.1,676,4.6,640,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18s-32.8,15.9-49.9,15.9c-13.1,0-19.7-4-26.3-9.7h0c-6.5-5.6-13.2-13-26.3-13C375.8,19.7,376,35,356.9,35c-17.6,0-19.7-13-38-13-15.1,0-14.9,11.1-38,11.1C251.5,33.1,255,4.6,219,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18S43.3,42.4,26.3,42.4c-13.1,0-19.7-4-26.3-9.7V562.6c6.5,5.6,13.2,12.9,26.2,12.9,18.9,0,18.7-15.2,37.9-15.2,17.6,0,19.6,12.9,38,12.9,15,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.8-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6h0c6.5,5.7,13.2,13,26.3,13,18.9,0,18.7-15.2,37.8-15.2,17.6,0,19.7,12.9,38,12.9,15.1,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.9-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6V32.7C835.5,27.1,828.8,19.7,815.8,19.7Z" />
      </clipPath>       
  </svg>

​

资源：

https://www.w3.org/TR/SVG11/masking.html#ClipPathElementClipPathUnitsAttribute

https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/clipPathUnits

https://www.sarasoueidan.com/blog/css-svg-clipping/

Answer 1

当使用clipPathUnits="objectBoundingBox"时，裁剪路径的对象包围框的宽度和高度被认为是长度为1单位值。

为了实现这一点，要么需要重写路径的d属性，要么可以缩放路径。在本例中，我使用transform="scale(0.00118,0.0017)"

 <clipPath id="wav" clipPathUnits="objectBoundingBox">
            <path transform="scale(0.00118,0.0017)" id="thePath" d="M815.8,19.7c-18.9,0-18.7,15.3-37.9,15.3-17.....

才能知道该用什么价值

1. 我得到了路径的边框：

让bb=thePath.getBBox();

1. I使用bb.width和bb.height来获得比例尺：

设sx = 1/bb.width；sy =1/bb.High

1. I缩放路径：

scale(${sx},${sy})) thePath.setAttribute("transform“)

​

body {
  background: #333;
}

#hero {
  background: url(https://source.unsplash.com/random);
  height: 120vh;
  background-color: #ff0000;
  width: 100vw;
  background-size: cover;
  clip-path: url(#wav);
}

#hero2 {
  background: url(https://source.unsplash.com/random);
  height: 120vh;
  background-color: #ff0000;
  width: 100vw;
  background-size: cover;
  clip-path: url(#wav2);
}

<div id="hero"></div>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
      <clipPath id="wav" clipPathUnits="objectBoundingBox">
        <path transform="scale(0.00118,0.0017)"  id="thePath" d="M815.8,19.7c-18.9,0-18.7,15.3-37.9,15.3-17.6,0-19.6-13-38-13-15,0-14.9,11.1-38,11.1C672.5,33.1,676,4.6,640,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18s-32.8,15.9-49.9,15.9c-13.1,0-19.7-4-26.3-9.7h0c-6.5-5.6-13.2-13-26.3-13C375.8,19.7,376,35,356.9,35c-17.6,0-19.7-13-38-13-15.1,0-14.9,11.1-38,11.1C251.5,33.1,255,4.6,219,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18S43.3,42.4,26.3,42.4c-13.1,0-19.7-4-26.3-9.7V562.6c6.5,5.6,13.2,12.9,26.2,12.9,18.9,0,18.7-15.2,37.9-15.2,17.6,0,19.6,12.9,38,12.9,15,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.8-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6h0c6.5,5.7,13.2,13,26.3,13,18.9,0,18.7-15.2,37.8-15.2,17.6,0,19.7,12.9,38,12.9,15.1,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.9-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6V32.7C835.5,27.1,828.8,19.7,815.8,19.7Z" />
      </clipPath>       
  </svg>


<div id="hero2"></div>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
      <clipPath id="wav2" clipPathUnits="objectBoundingBox">
        <path d="M815.8,19.7c-18.9,0-18.7,15.3-37.9,15.3-17.6,0-19.6-13-38-13-15,0-14.9,11.1-38,11.1C672.5,33.1,676,4.6,640,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18s-32.8,15.9-49.9,15.9c-13.1,0-19.7-4-26.3-9.7h0c-6.5-5.6-13.2-13-26.3-13C375.8,19.7,376,35,356.9,35c-17.6,0-19.7-13-38-13-15.1,0-14.9,11.1-38,11.1C251.5,33.1,255,4.6,219,4.6s-40.1,39.9-79.8,39.9c-33,0-38.7-18-63-18S43.3,42.4,26.3,42.4c-13.1,0-19.7-4-26.3-9.7V562.6c6.5,5.6,13.2,12.9,26.2,12.9,18.9,0,18.7-15.2,37.9-15.2,17.6,0,19.6,12.9,38,12.9,15,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.8-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6h0c6.5,5.7,13.2,13,26.3,13,18.9,0,18.7-15.2,37.8-15.2,17.6,0,19.7,12.9,38,12.9,15.1,0,14.9-11,38-11,29.4,0,25.9,28.5,61.9,28.5s40.1-39.9,79.8-39.9c33,0,38.7,18,63,18s32.9-15.9,49.9-15.9c13.1,0,19.7,4,26.3,9.6V32.7C835.5,27.1,828.8,19.7,815.8,19.7Z" />
      </clipPath>       
  </svg>

​

这是Sara Soueidan的文章：

当您使用objectBoundingBox值时，为<clipPath>内容指定的坐标必须在0，1的范围内。

这是来自MDN的

objectBoundingBox这个值表示元素内的所有坐标都相对于应用裁剪路径的元素的边界框。这意味着坐标系的原点是物体包围框的左上角，物体包围框的宽度和高度被认为是长度为1单位值。