具有切角和半透明背景的元素

Question

我需要创建一个带有切角和边框的流体形状。该形状需要能够位于未知背景上。这本身不是问题，但我还需要这个 element/s 的背景是半透明的。

这是我目前所拥有的...

* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

body {
    background: pink;
}

.sidebar-widget {
    border: 1px solid #44AAAB;
    border-right: none;
    border-bottom: none;
    position: relative;
    padding: 15px 0 0 15px;
    margin-bottom: 20px;
}

.sidebar-widget .inner {
    position: relative;
    padding: 15px 0 0 15px;
    left: -15px;
    top: -15px;
    background: #f2f2f2;
}

.sidebar-widget .inner:before {
    content: "";
    width: 100%;
    height: 15px;
    background: #f2f2f2;
    border: 1px solid #44AAAB;
    border-right: none;
    border-top: none;
    position: absolute;
    left: -1px;
    bottom: -16px;
}

.sidebar-widget .inner .content:after {
    content: "";
    width: 15px;
    height: 100%;
    background: #f2f2f2;
    border: 1px solid #44AAAB;
    border-left: none;
    border-bottom: none;
    position: absolute;
    right: -16px;
    top: -1px;
}

.corner {
    width: 22px;
    height: 22px;
    border-right: 1px solid #44AAAB;
    background: #f2f2f2;
    position: absolute;
    right: 4px;
    bottom: 4px;
    transform: rotate(45deg);
    z-index: 1;
}

.sidebar-widget.trans-bg .inner,
.sidebar-widget.trans-bg .inner:before,
.sidebar-widget.trans-bg .inner .content:after,
.trans-bg .corner {
    background: rgba(0,0,0,0.5);
}

<div class="sidebar-widget">
    <div class="corner"></div>
    <div class="inner">
        <div class="content">
            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam tellus felis, faucibus id velit eget, auctor tristique ex. Pellentesque id dolor risus. Donec tincidunt, nisl id laoreet tristique, ligula magna placerat mi, id congue magna diam ut sem. Aenean ornare eros nec sapien porta, laoreet venenatis est lobortis.
        </div>
    </div>
</div>

<div class="sidebar-widget trans-bg">
    <div class="corner"></div>
    <div class="inner">
        <div class="content">
            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam tellus felis, faucibus id velit eget, auctor tristique ex. Pellentesque id dolor risus. Donec tincidunt, nisl id laoreet tristique, ligula magna placerat mi, id congue magna diam ut sem. Aenean ornare eros nec sapien porta, laoreet venenatis est lobortis.
        </div>
    </div>
</div>

此方法在元素具有纯色背景时有效，但如您所见，在使用半透明背景时，用于创建切角的方形元素清晰可见。谁能想出办法解决这个问题？

JSFiddle version

Answer 1

您可以在 .corner 中使用另一个元素，请参见下面的示例：

<style>
    .corner, .corner_inner { /* added .corner_inner to your styles */
        width: 22px; 
        height: 22px; 
        border-right: 1px solid #44AAAB; 
        background: #f2f2f2; 
        position: absolute; 
        right: 4px; 
        bottom: 4px; 
        transform: rotate(45deg); 
        z-index: 1;
    }

    .trans-bg .corner {background: transparent} /* overwrite the background above */

    .trans-bg .corner_inner { /* set background and position for inner element */
        width: 11px; 
        height: 11px; 
        right: -1px; 
        bottom: 0; 
        background: rgba(0,0,0,0.5);
    }
</style>

<div class="sidebar-widget trans-bg">
    <div class="corner">
        <div class="corner_inner"></div>
    </div>
    ...
</div>

http://jsfiddle.net/6Lyph6zj/3/

我已经编辑了你的样式，一些属性被覆盖并且可以被删除。我的意思是您可以更好地理解我所做的更改。

Answer 2

任何对这里感兴趣的人都是我最终的做法。

用 overflow: hidden;

将 .corner 包裹在另一个元素中

* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

body {
    background: pink;
}

.sidebar-widget {
    border: 1px solid #44AAAB;
    border-right: none;
    border-bottom: none;
    position: relative;
    padding: 15px 0 0 15px;
    margin-bottom: 20px;
}

.sidebar-widget .inner {
    position: relative;
    padding: 15px 0 0 15px;
    left: -15px;
    top: -15px;
    background: #f2f2f2;
}

.sidebar-widget .inner:before {
    content: "";
    width: 100%;
    height: 15px;
    background: #f2f2f2;
    border: 1px solid #44AAAB;
    border-right: none;
    border-top: none;
    position: absolute;
    left: -1px;
    bottom: -16px;
}

.sidebar-widget .inner .content:after {
    content: "";
    width: 15px;
    height: 100%;
    background: #f2f2f2;
    border: 1px solid #44AAAB;
    border-left: none;
    border-bottom: none;
    position: absolute;
    right: -16px;
    top: -1px;
}

.corner-mask {
    width: 15px;
    height: 15px;
    position: absolute;
    right: 0;
    bottom: 0;
    overflow: hidden;
}

.corner {
    width: 22px;
    height: 22px;
    border-right: 1px solid #44AAAB;
    background: #f2f2f2;
    position: absolute;
    right: 4px;
    bottom: 4px;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    transform: rotate(45deg);
    z-index: 1;
}

.sidebar-widget.trans-bg .inner,
.sidebar-widget.trans-bg .inner:before,
.sidebar-widget.trans-bg .inner .content:after,
.trans-bg .corner {
    background: rgba(0,0,0,0.5);
}

<div class="sidebar-widget">
    <div class="corner-mask">
        <div class="corner"></div>
    </div>
    <div class="inner">
        <div class="content">
            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam tellus felis, faucibus id velit eget, auctor tristique ex. Pellentesque id dolor risus. Donec tincidunt, nisl id laoreet tristique, ligula magna placerat mi, id congue magna diam ut sem. Aenean ornare eros nec sapien porta, laoreet venenatis est lobortis.
        </div>
    </div>
</div>

<div class="sidebar-widget trans-bg">
    <div class="corner-mask">
        <div class="corner"></div>
    </div>
    <div class="inner">
        <div class="content">
            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam tellus felis, faucibus id velit eget, auctor tristique ex. Pellentesque id dolor risus. Donec tincidunt, nisl id laoreet tristique, ligula magna placerat mi, id congue magna diam ut sem. Aenean ornare eros nec sapien porta, laoreet venenatis est lobortis.
        </div>
    </div>
</div>

JSFiddle version