clip-path - CSS（层叠样式表）编辑

clip-path CSS 属性使用裁剪方式创建元素的可显示区域。区域内的部分显示，区域外的隐藏。

语法

/* Keyword values */
clip-path: none;

/* <clip-source> values */
clip-path: url(resources.svg#c1);

/* <geometry-box> values */
clip-path: margin-box;
clip-path: border-box;
clip-path: padding-box;
clip-path: content-box;
clip-path: fill-box;
clip-path: stroke-box;
clip-path: view-box;

/* <basic-shape> values */
clip-path: inset(100px 50px);
clip-path: circle(50px at 0 100px);
clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
clip-path: path('M0.5,1 C0.5,1,0,0.7,0,0.3 A0.25,0.25,1,1,1,0.5,0.3 A0.25,0.25,1,1,1,1,0.3 C1,0.7,0.5,1,0.5,1 Z');

/* Box and shape values combined */
clip-path: padding-box circle(50px at 0 100px);

/* Global values */
clip-path: inherit;
clip-path: initial;
clip-path: unset;

clip-path属性指定为下面列出的值的一个或多个值的组合.

取值

<clip-source>

用 <url> 表示剪切元素的路径

<basic-shape>

一种形状，其大小和位置由<几何盒>值定义。如果没有指定几何框，则边框将用作参考框

<geometry-box>

如果同 <basic-shape> 一起声明，它将为基本形状提供相应的参考框盒。通过自定义，它将利用确定的盒子边缘包括任何形状边角（比如说，被 border-radius 定义的剪切路径）。几何框盒可以有以下的值中的一个：

margin-box: 使用 margin box 作为引用框。
border-box: 使用 border box 作为引用框。
padding-box: 使用 padding box 作为引用框。
content-box: 使用 content box 作为引用框。
fill-box: 利用对象边界框作为引用框。
stroke-box: 使用笔触边界框（stroke bounding box）作为引用框
view-box: 使用最近的 SVG 视口（viewport）作为引用框。如果viewBox 属性被指定来为元素创建 SVG 视口，引用框将会被定位在坐标系的原点，引用框位于由 viewBox 属性建立的坐标系的原点，引用框的尺寸用来设置 viewBox 属性的宽高值。

none

不创建的剪切路径。

Note: A computed value other than none results in the creation of a new stacking context the same way that CSS opacity does for values other than 1.

正式语法

<clip-source> | [ <basic-shape> || <geometry-box> ] | nonewhere 
<clip-source> = <url>
<basic-shape> = <inset()> | <circle()> | <ellipse()> | <polygon()> | <path()>
<geometry-box> = <shape-box> | fill-box | stroke-box | view-box
where 
<inset()> = inset( <length-percentage>{1,4} [ round <'border-radius'> ]? )
<circle()> = circle( [ <shape-radius> ]? [ at <position> ]? )
<ellipse()> = ellipse( [ <shape-radius>{2} ]? [ at <position> ]? )
<polygon()> = polygon( <fill-rule>? , [ <length-percentage> <length-percentage> ]# )
<path()> = path( [ <fill-rule>, ]? <string> )
<shape-box> = <box> | margin-box
where 
<length-percentage> = <length> | <percentage>
<shape-radius> = <length-percentage> | closest-side | farthest-side
<position> = [ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]
<fill-rule> = nonzero | evenodd
<box> = border-box | padding-box | content-box

例子

HTML 与 SVG 之间的对比

<svg class="defs">
  <defs>
    <clipPath id="myPath" clipPathUnits="objectBoundingBox">
      <path d="M0.5,1 C0.5,1,0,0.7,0,0.3 A0.25,0.25,1,1,1,0.5,0.3 A0.25,0.25,1,1,1,1,0.3 C1,0.7,0.5,1,0.5,1 Z" />
    </clipPath>
  </defs>
</svg>

<div class="grid">
  <div class="col">
    <div class="note">clip-path: none</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="none">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="none">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: url(#myPath)<br><br>
      Assuming the following clipPath definition:
      <pre>
&lt;svg&gt;
  &lt;clipPath id="myPath" clipPathUnits="objectBoundingBox"&gt;
    &lt;path d="M0.5,1
      C 0.5,1,0,0.7,0,0.3
      A 0.25,0.25,1,1,1,0.5,0.3
      A 0.25,0.25,1,1,1,1,0.3
      C 1,0.7,0.5,1,0.5,1 Z" /&gt;
  &lt;/clipPath&gt;
&lt;/svg&gt;</pre>
    </div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="svg">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="svg">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: path('M15,45 A30,30,0,0,1,75,45 A30,30,0,0,1,135,45 Q135,90,75,130 Q15,90,15,45 Z')
    </div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="svg2">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="svg2">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>



    <div class="note">clip-path: circle(25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape1">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape1">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape2">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape2">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: fill-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape3">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape3">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: stroke-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape4">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape4">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: view-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape5">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape5">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: margin-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape6">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape6">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: border-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape7">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape7">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: padding-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape8">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape8">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>

    <div class="note">clip-path: content-box circle(25% at 25% 25%)</div>
    <div class="row">
      <div class="cell"> <span>HTML</span>
        <div class="container">
          <p class="shape9">
            I LOVE<br><em>clipping</em>
          </p>
        </div>
      </div>
      <div class="cell"> <span>SVG</span>
        <div class="container viewbox">
          <svg viewBox="0 0 192 192">
            <g class="shape9">
              <rect x="24" y="24" width="144" height="144" />
              <text x="96" y="91">I LOVE</text>
              <text x="96" y="109" class="em">clipping</text>
            </g>
          </svg>
        </div>
      </div>
    </div>
  </div>
</div>

html,body {
  height: 100%;
  box-sizing: border-box;
  background: #EEE;
}

.grid {
  width: 100%;
  height: 100%;
  display: flex;
  font: 1em monospace;
}

.row {
  display: flex;
  flex: 1 auto;
  flex-direction: row;
  flex-wrap: wrap;
}

.col {
  flex: 1 auto;
}

.cell {
  margin: .5em;
  padding: .5em;
  background-color: #FFF;
  overflow: hidden;
  text-align: center;
  flex: 1;
}

.note {
  background: #fff3d4;
  padding: 1em;
  margin: .5em .5em 0;
  font: .8em sans-serif;
  text-align: left;
  white-space: nowrap;
}

.note + .row .cell {
  margin-top: 0;
}

.container {
  display: inline-block;
  border: 1px dotted grey;
  position:relative;
}

.container:before {
  content: 'margin';
  position: absolute;
  top: 2px;
  left: 2px;
  font: italic .6em sans-serif;
}

.viewbox {
  box-shadow: 1rem 1rem 0 #EFEFEF inset, -1rem -1rem 0 #EFEFEF inset;
}

.container.viewbox:after {
  content: 'viewbox';
  position: absolute;
  left: 1.1rem;
  top: 1.1rem;
  font: italic .6em sans-serif;
}

.cell span {
  display: block;
  margin-bottom: .5em;
}

p {
  font-family: sans-serif;
  background: #000;
  color: pink;
  margin: 2em;
  padding: 3em 1em;
  border: 1em solid pink;
  width: 6em;
}

.none { clip-path: none; }
.svg  { clip-path: url(#myPath); }
.svg2 { clip-path: path('M15,45 A30,30,0,0,1,75,45 A30,30,0,0,1,135,45 Q135,90,75,130 Q15,90,15,45 Z');}
.shape1 { clip-path: circle(25%); }
.shape2 { clip-path: circle(25% at 25% 25%); }
.shape3 { clip-path: fill-box    circle(25% at 25% 25%); }
.shape4 { clip-path: stroke-box  circle(25% at 25% 25%); }
.shape5 { clip-path: view-box    circle(25% at 25% 25%); }
.shape6 { clip-path: margin-box  circle(25% at 25% 25%); }
.shape7 { clip-path: border-box  circle(25% at 25% 25%); }
.shape8 { clip-path: padding-box circle(25% at 25% 25%); }
.shape9 { clip-path: content-box circle(25% at 25% 25%); }

.defs {
  width: 0;
  height: 0;
  margin: 0;
}

pre { margin-bottom: 0; }

svg {
  margin: 1em;
  font-family: sans-serif;
  width: 192px;
  height: 192px;
}

svg rect {
  stroke: pink;
  stroke-width: 16px;
}

svg text {
  fill: pink;
  text-anchor: middle;
}

svg text.em {
  font-style: italic;
}

完整示例

HTML

<img id="clipped" src="https://mdn.mozillademos.org/files/12668/MDN.svg"
    alt="MDN logo">
<svg height="0" width="0">
  <defs>
    <clipPath id="cross">
      <rect y="110" x="137" width="90" height="90"/>
      <rect x="0" y="110" width="90" height="90"/>
      <rect x="137" y="0" width="90" height="90"/>
      <rect x="0" y="0" width="90" height="90"/>
    </clipPath>
  </defs>
</svg>

<select id="clipPath">
  <option value="none">none</option>
  <option value="circle(100px at 110px 100px)">circle</option>
  <option value="url(#cross)" selected>cross</option>
  <option value="inset(20px round 20px)">inset</option>
  <option value="path('M 0 200 L 0,110 A 110,90 0,0,1 240,100 L 200 340 z')">path</option>
</select>

CSS

#clipped {
  margin-bottom: 20px;
  clip-path: url(#cross);
}

JavaScript

var clipPathSelect = document.getElementById("clipPath");
clipPathSelect.addEventListener("change", function (evt) {
  document.getElementById("clipped").style.clipPath = evt.target.value;
});

结果

规范

Specification	Status	Comment
CSS Masking Module Level 1 clip-path	Candidate Recommendation	Extends its application to HTML elements
Scalable Vector Graphics (SVG) 1.1 (Second Edition) clip-path	Recommendation	Initial definition (applies to SVG elements only)

初始值	`none`
适用元素	all elements; In SVG, it applies to container elements excluding the `defs` element and all graphics elements
是否是继承属性	否
Percentages	refer to reference box when specified, otherwise border-box
计算值	as specified, but with `url` values made absolute
Animation type	yes, as specified for `basic-shape`, otherwise no