使用CSS剪切角落

Question

我正在寻找"切割"div的左上角,就像你已经折叠了一页的一角.

我想用纯CSS做,有什么方法吗？

Answer 1

如果父元素具有纯色背景,则可以使用伪元素来创建效果:

div {
    height: 300px;
    background: red;
    position: relative;
}

div:before {
    content: '';
    position: absolute;
    top: 0; right: 0;
    border-top: 80px solid white;
    border-left: 80px solid red;
    width: 0;
}

http://jsfiddle.net/2bZAW/

PS 即将到来border-corner-shape的正是您正在寻找的.太糟糕了,它可能会从规范中删除,并且永远不会进入野外的任何浏览器:(

Answer 2

如果需要透明切边,可以使用旋转的伪元素作为背景,div并将其定位为切出所需的角:

body {
  background: url(http://i.imgur.com/k8BtMvj.jpg);
  background-size: cover;
}
div {
  position: relative;
  width: 50%;
  margin: 0 auto;
  overflow: hidden;
  padding: 20px;
  text-align: center;
}
div:after {
  content: '';
  position: absolute;
  width: 1100%; height: 1100%;
  top: 20px; right: -500%;
  background: rgba(255,255,255,.8);
  transform-origin: 54% 0;
  transform: rotate(45deg);
  z-index: -1;
}

<div>
  ... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>
</div>

请注意,此解决方案使用转换,您需要添加所需的供应商前缀.有关更多信息,请参阅canIuse.

要剪切右下角,可以将伪元素的top,transform和transform-origin属性更改为:

body {
  background: url(http://i.imgur.com/k8BtMvj.jpg);
  background-size: cover;
}
div {
  position: relative;
  width: 50%;
  margin: 0 auto;
  overflow: hidden;
  padding: 20px;
  text-align: center;
}
div:after {
  content: '';
  position: absolute;
  width: 1100%; height: 1100%;
  bottom: 20px; right: -500%;
  background: rgba(255,255,255,.8);
  transform-origin: 54% 100%;
  transform: rotate(-45deg);
  z-index: -1;
}

<div>
  ... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>... content ...<br/>
</div>

Answer 3

CSS剪辑路径

使用clip-path是一种新的,即将到来的替代方案.它开始得到越来越多的支持,现在已经有了很好的记录.由于它使用SVG来创建形状,因此它可以直接开箱即用.

• 我可以用吗
• 剪辑路径生成器

div {
  width: 200px;
  min-height: 200px;
  -webkit-clip-path: polygon(0 0, 0 100%, 100% 100%, 100% 25%, 75% 0);
  clip-path: polygon(0 0, 0 100%, 100% 100%, 100% 25%, 75% 0);
  background: lightblue;
}

<div>
  <p>Some Text</p>
</div>

CSS转换

我有一个替代web-tiki的转换答案.

body {
  background: lightgreen;
}
div {
  width: 200px;
  height: 200px;
  background: transparent;
  position: relative;
  overflow: hidden;
}
div.bg {
  width: 200%;
  height: 200%;
  background: lightblue;
  position: absolute;
  top: 0;
  left: -75%;
  transform-origin: 50% 50%;
  transform: rotate(45deg);
  z-index: -1;
}

<div>
  <div class="bg"></div>
  <p>Some Text</p>
</div>

Answer 4

我有一个用于以下某些代码的在线生成器：https ://css-generators.com/custom-corners/

您可以使用遮罩和 CSS 变量来更好地控制整个形状。它反应灵敏、透明并允许任何类型的背景：

.box {
  --all:0px;
  width:200px;
  height:150px;
  display:inline-block;
  margin:10px;
  background:red;
  -webkit-mask:
     linear-gradient(  45deg, transparent 0 var(--bottom-left,var(--all)) ,#fff 0) bottom left,
     linear-gradient( -45deg, transparent 0 var(--bottom-right,var(--all)),#fff 0) bottom right,
     linear-gradient( 135deg, transparent 0 var(--top-left,var(--all))    ,#fff 0) top left,
     linear-gradient(-135deg, transparent 0 var(--top-right,var(--all))   ,#fff 0) top right;
   -webkit-mask-size:50.5% 50.5%;
   -webkit-mask-repeat:no-repeat;
}


body {
  background:grey;
}

<div class="box" style="--top-left:20px"></div>
<div class="box" style="--top-right:20px;--bottom-right:50px;background:radial-gradient(red,yellow)"></div>
<div class="box" style="--all:30px;background:url(https://picsum.photos/id/104/200/200)"></div>
<div class="box" style="--all:30px;--bottom-right:0px;background:linear-gradient(red,blue)"></div>
<div class="box" style="--all:50%;width:150px;background:green"></div>
<div class="box" style="--all:12%;width:150px;background:repeating-linear-gradient(45deg,#000 0 10px,#fff 0 20px)"></div>

如果你想考虑边界，下面是：

.box {
  --all:0px;
  --b:pink;
  
  width:200px;
  height:150px;
  display:inline-block;
  margin:10px;
  border:5px solid var(--b);
  background:
     linear-gradient(  45deg, var(--b) 0 calc(var(--bottom-left,var(--all)) + 5px) ,transparent 0) bottom left /50% 50%,
     linear-gradient( -45deg, var(--b) 0 calc(var(--bottom-right,var(--all)) + 5px),transparent 0) bottom right/50% 50%,
     linear-gradient( 135deg, var(--b) 0 calc(var(--top-left,var(--all)) + 5px)    ,transparent 0) top left    /50% 50%,
     linear-gradient(-135deg, var(--b) 0 calc(var(--top-right,var(--all)) + 5px)   ,transparent 0) top right   /50% 50%,
     var(--img,red);
  background-origin:border-box;
  background-repeat:no-repeat;
  -webkit-mask:
     linear-gradient(  45deg, transparent 0 var(--bottom-left,var(--all)) ,#fff 0) bottom left,
     linear-gradient( -45deg, transparent 0 var(--bottom-right,var(--all)),#fff 0) bottom right,
     linear-gradient( 135deg, transparent 0 var(--top-left,var(--all))    ,#fff 0) top left,
     linear-gradient(-135deg, transparent 0 var(--top-right,var(--all))   ,#fff 0) top right;
   -webkit-mask-size:50.5% 50.5%;
   -webkit-mask-repeat:no-repeat;
}


body {
  background:grey;
}

<div class="box" style="--top-left:20px"></div>
<div class="box" style="--top-right:20px;--bottom-right:50px;--img:radial-gradient(red,yellow);--b:white;"></div>
<div class="box" style="--all:30px;--img:url(https://picsum.photos/id/104/200/200) center/cover;--b:orange;"></div>
<div class="box" style="--all:30px;--bottom-right:0px;--img:linear-gradient(red,blue)"></div>
<div class="box" style="--all:50%;width:150px;--img:green;--b:red;"></div>
<div class="box" style="--all:12%;width:150px;--img:repeating-linear-gradient(45deg,#000 0 10px,#fff 0 20px)"></div>

我们还添加一些半径：

.box {
  --all:0px;
  --b:pink;
  
  width:200px;
  height:150px;
  display:inline-block;
  margin:10px;
  filter:url(#round);
}
.box::before {
  content:"";
  position:absolute;
  top:0;
  left:0;
  right:0;
  bottom:0;
  background:var(--img,red);
  -webkit-mask:
     linear-gradient(  45deg, transparent 0 var(--bottom-left,var(--all)) ,#fff 0) bottom left,
     linear-gradient( -45deg, transparent 0 var(--bottom-right,var(--all)),#fff 0) bottom right,
     linear-gradient( 135deg, transparent 0 var(--top-left,var(--all))    ,#fff 0) top left,
     linear-gradient(-135deg, transparent 0 var(--top-right,var(--all))   ,#fff 0) top right;
   -webkit-mask-size:50.5% 50.5%;
   -webkit-mask-repeat:no-repeat;
}

body {
  background:grey;
}

<div class="box" style="--top-left:20px"></div>
<div class="box" style="--top-right:20px;--bottom-right:50px;--img:radial-gradient(red,yellow);--b:white;"></div>
<div class="box" style="--all:30px;--img:url(https://picsum.photos/id/104/200/200) center/cover;--b:orange;"></div>
<div class="box" style="--all:30px;--bottom-right:0px;--img:linear-gradient(red,blue)"></div>
<div class="box" style="--all:50%;width:150px;--img:green;--b:red;"></div>
<div class="box" style="--all:12%;width:150px;--img:repeating-linear-gradient(45deg,#000 0 10px,#fff 0 20px)"></div>

<svg style="visibility: hidden; position: absolute;" width="0" height="0" xmlns="http://www.w3.org/2000/svg" version="1.1">
  <defs>
        <filter id="round">
            <feGaussianBlur in="SourceGraphic" stdDeviation="5" result="blur" />    
            <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 19 -9" result="goo" />
            <feComposite in="SourceGraphic" in2="goo" operator="atop"/>
        </filter>
    </defs>
</svg>

Answer 5

这是使用CSS transform: skew(45deg)产生切角效果的另一种方法.形状本身包含三个元素(1个真元素和2个伪元素),如下所示:

• 主容器div元素具有overflow: hidden并产生左边框.
• 所述:before伪元件,其是20%的父容器的高度,并且具有偏斜变换施加到其上.此元素可以生成顶部的边框,并在右侧切割(倾斜)边框.
• 所述:after伪元件,其是80%的母体(基本上,剩余高度)的高度,并产生下边框,右边框的剩余部分.

产生的输出是响应性的,在顶部产生透明切口并支持透明背景.

div {
  position: relative;
  height: 100px;
  width: 200px;
  border-left: 2px solid beige;
  overflow: hidden;
}
div:after,
div:before {
  position: absolute;
  content: '';
  width: calc(100% - 2px);
  left: 0px;
  z-index: -1;
}
div:before {
  height: 20%;
  top: 0px;
  border: 2px solid beige;
  border-width: 2px 3px 0px 0px;
  transform: skew(45deg);
  transform-origin: right bottom;
}
div:after {
  height: calc(80% - 4px);
  bottom: 0px;
  border: 2px solid beige;
  border-width: 0px 2px 2px 0px;
}
.filled:before, .filled:after {
  background-color: beige;
}

/* Just for demo */

div {
  float: left;
  color: beige;
  padding: 10px;
  transition: all 1s;
  margin: 10px;
}
div:hover {
  height: 200px;
  width: 300px;
}
div.filled{
  color: black;
}
body{
 background-image: radial-gradient(circle, #3F9CBA 0%, #153346 100%);
}

<div class="cut-corner">Some content</div>
<div class="cut-corner filled">Some content</div>

以下是使用linear-gradient背景图像产生切角效果的另一种方法.使用3个梯度图像(下面给出)的组合:

• 一个线性渐变(向左下方倾斜)以产生切角效果.此渐变具有固定的25px x 25px大小.
• 一个线性渐变,在三角形左侧提供纯色,从而产生切割效果.即使它产生纯色,也会使用渐变,因为只有在使用图像或渐变时我们才能控制背景的大小,位置.该梯度在X轴上位于-25px处(基本上意味着它将在切割存在的位置之前结束).
• 另一种类似于上述的梯度再次产生纯色,但在Y轴上向下定位25px(再次省略切割区域).

产生的输出是响应的,产生透明切割并且不需要任何额外的元素(真实的或伪的).缺点是这种方法只有在背景(填充)是纯色并且很难产生边框时才有效(但仍然可以在片段中看到).

.cut-corner {
  height: 100px;
  width: 200px;
  background-image: linear-gradient(to bottom left, transparent 50%, beige 50%), linear-gradient(beige, beige), linear-gradient(beige, beige);
  background-size: 25px 25px, 100% 100%, 100% 100%;
  background-position: 100% 0%, -25px 0%, 100% 25px;
  background-repeat: no-repeat;
}
.filled {
  background-image: linear-gradient(black, black), linear-gradient(black, black), linear-gradient(black, black), linear-gradient(black, black), linear-gradient(to bottom left, transparent calc(50% - 1px), black calc(50% - 1px), black calc(50% + 1px), beige calc(50% + 1px)), linear-gradient(beige, beige), linear-gradient(beige, beige);
  background-size: 2px 100%, 2px 100%, 100% 2px, 100% 2px, 25px 25px, 100% 100%, 100% 100%;
  background-position: 0% 0%, 100% 25px, -25px 0%, 0px 100%, 100% 0%, -25px 0%, 100% 25px;
}

/* Just for demo */

*{
  box-sizing: border-box;
  }
div {
  float: left;
  color: black;
  padding: 10px;
  transition: all 1s;
  margin: 10px;
}
div:hover {
  height: 200px;
  width: 300px;
}
body{
 background-image: radial-gradient(circle, #3F9CBA 0%, #153346 100%);
}

<div class="cut-corner">Some content</div>
<div class="cut-corner filled">Some content</div>

Answer 6

你可以用linear-gradient.让我们说父母div有一个背景图像,你需要一个div坐在它上面的灰色背景和狗耳的左角.你可以这样做:

.parent-div { background: url('/image.jpg'); }
.child-div { 
   background: #333;
   background: linear-gradient(135deg, transparent 30px, #333 0);
}

在CodePen上看到它

进一步阅读:

• CSS-Tricks的CSS渐变
• 具有CSS3渐变的斜角和负边界半径

Answer 7

如果你需要一个对角线边框而不是一个对角线,你可以用每个伪元素堆叠2个div:

DEMO

http://codepen.io/remcokalf/pen/BNxLMJ

.container {
  padding: 100px 200px;
  overflow: hidden;
}

div.diagonal {
  background: #da1d00;
  color: #fff;
  font-family: Arial, Helvetica, sans-serif;
  width: 300px;
  height: 300px;
  padding: 70px;
  position: relative;
  margin: 30px;
  float: left;
}

div.diagonal2 {
  background: #da1d00;
  color: #fff;
  font-family: Arial, Helvetica, sans-serif;
  width: 300px;
  height: 300px;
  padding: 70px;
  position: relative;
  margin: 30px;
  background: #da1d00 url(http://www.remcokalf.nl/background.jpg) left top;
  background-size: cover;
  float: left;
}

div.diagonal3 {
  background: #da1d00;
  color: #da1d00;
  font-family: Arial, Helvetica, sans-serif;
  width: 432px;
  height: 432px;
  padding: 4px;
  position: relative;
  margin: 30px;
  float: left;
}

div.inside {
  background: #fff;
  color: #da1d00;
  font-family: Arial, Helvetica, sans-serif;
  width: 292px;
  height: 292px;
  padding: 70px;
  position: relative;
}

div.diagonal:before,
div.diagonal2:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  border-top: 80px solid #fff;
  border-right: 80px solid transparent;
  width: 0;
}

div.diagonal3:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  border-top: 80px solid #da1d00;
  border-right: 80px solid transparent;
  width: 0;
  z-index: 1;
}

div.inside:before {
  content: '';
  position: absolute;
  top: -4px;
  left: -4px;
  border-top: 74px solid #fff;
  border-right: 74px solid transparent;
  width: 0;
  z-index: 2;
}

h2 {
  font-size: 30px;
  line-height: 1.3em;
  margin-bottom: 1em;
  position: relative;
  z-index: 1000;
}

p {
  font-size: 16px;
  line-height: 1.6em;
  margin-bottom: 1.8em;
}

#grey {
  width: 100%;
  height: 400px;
  background: #ccc;
  position: relative;
  margin-top: 100px;
}

#grey:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  border-top: 80px solid #fff;
  border-right: 80px solid #ccc;
  width: 400px;
}

<div id="grey"></div>
<div class="container">
  <div class="diagonal">
    <h2>Header title</h2>
    <p>Yes a CSS diagonal corner is possible</p>
  </div>
  <div class="diagonal2">
    <h2>Header title</h2>
    <p>Yes a CSS diagonal corner with background image is possible</p>
  </div>
  <div class="diagonal3">
    <div class="inside">
      <h2>Header title</h2>
      <p>Yes a CSS diagonal border is even possible with an extra div</p>
    </div>
  </div>
</div>

Answer 8

此代码允许您在矩形的每一侧切角:

div {
  display:block;
  height: 300px;
  width: 200px;
  background: url('http://lorempixel.com/180/290/') no-repeat;
  background-size:cover;

  -webkit-clip-path: polygon(10px 0%, calc(100% - 10px) 0%, 100% 10px, 100% calc(100% - 10px), calc(100% - 10px) 100%, 10px 100%, 0% calc(100% - 10px), 0% 10px);
  clip-path: polygon(10px 0%, calc(100% - 10px) 0%, 100% 10px, 100% calc(100% - 10px), calc(100% - 10px) 100%, 10px 100%, 0% calc(100% - 10px), 0% 10px);
}

http://jsfiddle.net/2bZAW/5552/

Answer 9

我们遇到了剪切元素背景颜色不同的问题。我们只想要右上角和左下角。

body {
 background-color: rgba(0,0,0,0.3)
 
}

.box {
 position: relative;
 display: block;
 background: blue;
 text-align: center;
 color: white;
 padding: 15px;
 margin: 50px;
}

.box:before,
.box:after {
 content: "";
 position: absolute;
 left: 0; 
 right: 0;
 bottom: 100%;
 border-bottom: 15px solid blue;
 border-left: 15px solid transparent;
 border-right: 15px solid transparent;
}

.box:before{
	border-left: 15px solid blue;
}

.box:after{
	border-right: 15px solid blue;
}

.box:after {
 bottom: auto;
 top: 100%;
 border-bottom: none;
 border-top: 15px solid blue;
}


/* Active box */
.box.active{
	background: white;
	color: black;
}



.active:before,
.active:after {
 border-bottom: 15px solid white;
}

.active:before{
	border-left: 15px solid white;
}

.active:after{
	border-right: 15px solid white;
}

.active:after {
 border-bottom: none;
 border-top: 15px solid white;
}

<div class="box">
 Some text goes here. Some text goes here. Some text goes here. Some text goes here.<br/>Some text goes here.<br/>Some text goes here.<br/>Some text goes here.<br/>Some text goes here.<br/>Some text goes here.<br/>
</div>
<div class="box">
 Some text goes here.
</div>
<div class="box active">
 Some text goes here.
 <span class="border-bottom"></span>
</div>
<div class="box">
 Some text goes here.
</div>