在选择器之前使用css

Question

我正在尝试将一个图像重叠在另一个图像上并从中制作圆形图像。

    <span onclick="someFunction()" id="swatch_123456" class="slider-color-swatches" style="background-image: url(anyImage.png);"></span>

.slider-color-swatches{
    position: relative;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    display: inline-block;
    vertical-align: top;
    overflow: hidden;
    margin-bottom: 10px;
    margin-right: 10px;
}
.slider-color-swatches::before{
    content: '';
    position: absolute;
    background-image: url('anyOtherIamge.pnenter image description hereg');
    left: 20%;
    width: 100%;
    height: 200%;
    top: 0;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    transform: rotate(45deg);
}

Here are the images as to what I want to do and where Iam able to get so far

Answer 1

试试这个.. 可能会工作..

{
    width: 28px;
    height: 28px;
    overflow: hidden;
    display: block;
    border-radius: 50%;
    -moz-border-radius: 50%;
    -webkit-border-radius: 50%;
    margin-bottom: 10px;
    -webkit-transition: all 0.3s ease-out;
    -moz-transition: all 0.3s ease-out;
    -o-transition: all 0.3s ease-out;
    transition: all 0.3s ease-out;
    margin: 0 auto;
}

Answer 2

尝试将display: block;添加到您的::before元素中。 这样做会使你的宽度和高度生效。

此外，添加margin: auto;会使其保持居中。

示例：

.slider-color-swatches::before {
    content: '';
    position: absolute;
    display: block;
    margin: auto;
    background-image: url('anyOtherIamge.pnenter image description hereg');
    left: 20%;
    width: 100%;
    height: 200%;
    top: 0;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    transform: rotate(45deg); }

如果您想尝试其他方法，请查看clipping and masking！