如何创建响应三角形作为右边界？

Question

我正在尝试为一个边框制作一个响应三角形,只有在边框上才可见hover.我尝试了下面的代码,但它不起作用,因为它使用静态border-width.当我有一个单字符串(单行)链接时,它是完美的,但是当字符串更多(超过一行)时,它就失败了.

这里的例子

代码在这里:

<ul>
  <li><a href="#">Lorem ipsum</a></li>
  <li><a href="#">Lorem ipsum</a></li>
  <li><a href="#">Lorem ipsum dolor sit amet</a></li>
</ul>  

SCSS在这里:

ul{
  width:120px;
  li{
    list-style-type: none;
    a{
      position:relative;
      display:block;
      padding:10px;
      color:#00f;
      text-decoration: none;
      &:hover{
        color:#fff;
        background:#00f;
        &:after{
          content:'';
          position: absolute;
          top: 0;
          right: -5px;
          height: 0;
          border-style: solid;
          border-width: 19px 0 19px 11px;
          border-color: #fff #fff #fff #00f;
        }
      }
    }
  }
}

最后一个链接失败.使用图像或图片不是解决问题的方法.

Answer 1

您不能使用border三角形方法在此处创建三角形,因为height您的元素是动态的.相反,您可以使用以下任何替代方案:

内联SVG +剪辑路径: ^推荐

您可以使用内联SVG并clip-path生成具有三角效果的条形图.该clip-path只盘旋而上的应用a标签等正常状态不受影响.该浏览器支持这个比CSS相当于好得多.

ul {
  width: 120px;
}
li {
  list-style-type: none;
}
a {
  position: relative;
  display: block;
  padding: 10px;
  color: #00f;
  text-decoration: none;
}
a:hover {
  -webkit-clip-path: url(#clip-shape);
  -moz-clip-path: url(#clip-shape);
  clip-path: url(#clip-shape);
  background: crimson;
}

<svg width="0" height="0">
  <defs>
    <clipPath id="clip-shape" clipPathUnits="objectBoundingBox">
      <polygon points="0,0 0.8,0 1,0.5 0.8,1 0,1" />
    </clipPath>
  </defs>
</svg>

<ul>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum dolor sit amet</a>
  </li>
</ul>

转换:

您可以transform: rotate(45deg)在伪元素上使用以生成三角形,然后将其放置在a生成形状的末尾.父级具有overflow: hidden剪切不需要显示的三角形部分的设置.

ul {
  width: 120px;
}
li {
  list-style-type: none;
}
a {
  position: relative;
  display: inline-block;
  color: blue;
  text-decoration: none;
  padding: 5px 25px 5px 5px;
  overflow: hidden;
}
a:after {
  content: '';
  position: absolute;
  top: 50%;
  right: 0%;
  height: 100%;
  width: 100%;
  background-color: inherit;
  transform-origin: 100% 0;
  transform: rotate(45deg);
  z-index: -1;
}
a:before {
  position: absolute;
  content: '';
  top: 0px;
  left: 0px;
  height: 100%;
  width: calc(100% - 25px);
  background-color: inherit;
  z-index: -1;
}
a:hover {
  background: crimson;
  background-clip: content-box;
  color: beige;
}

<!-- Library included just to avoid prefixes so that users with older browser can view -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>

<ul>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum dolor sit amet</a>
  </li>
</ul>

或者,您可以使用两个伪元素transform: skew(45deg)(应用于相反的方向)来获取三角形.这里父母也有overflow: hidden设置.

ul {
  width: 120px;
}
li {
  list-style-type: none;
  margin-bottom: 10px;
}
a {
  position: relative;
  display: block;
  padding: 10px;
  color: #00f;
  text-decoration: none;
  overflow: hidden;
}
a:before,
a:after {
  position: absolute;
  content: '';
  height: 50%;
  width: 100%;
  left: -15%;
  z-index: -1;
}
a:before {
  top: 0px;
  transform: skew(45deg);
}
a:after {
  bottom: 0px;
  transform: skew(-45deg);
}
a:hover:after,
a:hover:before {
  background: crimson;
}
a:hover{
  color: beige;
}

<!-- Library included just to avoid prefixes so that users with older browser can view -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>

<ul>
  <li><a href="#">Lorem ipsum</a>

  </li>
  <li><a href="#">Lorem ipsum</a>

  </li>
  <li><a href="#">Lorem ipsum dolor sit amet</a>

  </li>
</ul>

这些可能是最接近具有良好浏览器支持的纯CSS解决方案.但是,当高度进一步增加时,它们仍需要对padding-right(如rotate方法)和left(skew方法)等属性进行一些调整,因此不建议这样做.

CSS剪辑路径:

您可以使用多边形clip-path来创建一个带有三角效果的条形图hover.这里的缺点是浏览器支持CSS剪辑路径.

ul {
  width: 120px;
}
li {
  list-style-type: none;
}
a {
  position: relative;
  display: block;
  padding: 10px;
  color: #00f;
  text-decoration: none;
}
a:hover {
  -webkit-clip-path: polygon(0% 0%, 80% 0%, 100% 50%, 80% 100%, 0% 100%);
  background: crimson;
}

<ul>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum dolor sit amet</a>
  </li>
</ul>

线性渐变:

您也可以使用linear-gradient和下面的代码段中的伪元素组合,但已知渐变会产生锯齿状边缘,并不是真正推荐的.

ul {
  width: 120px;
}
li {
  list-style-type: none;
}
a {
  position: relative;
  display: block;
  padding: 10px;
  color: #00f;
  text-decoration: none;
}
a:after {
  content: '';
  display: none;
  position: absolute;
  right: -25px;
  top: 0px;
  width: 50px;
  height: 100%;
  background: linear-gradient(to top left, rgba(0, 0, 0, 0) 50%, crimson 50%), linear-gradient(to top right, crimson 50%, rgba(0, 0, 0, 0) 50%);
  background-size: 50% 50%;
  background-repeat: no-repeat;
  background-position: 100% 100%, 100% 0%;
  z-index: -1;
}
a:hover {
  background: crimson;
}
a:hover:after {
  display: block;
}

<!-- Library included just to avoid prefixes so that users with older browser can view -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>

<ul>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum</a>
  </li>
  <li><a href="#">Lorem ipsum dolor sit amet</a>
  </li>
</ul>