背景图像如何使用CSS滤镜效果

Question

我有一个JPEG文件，我正在将其用作搜索页面的背景图像，并且我正在使用CSS进行设置，因为我正在Backbone.js上下文中工作：

background-image: url("whatever.jpg");

我想仅对背景应用CSS 3模糊滤镜，但是我不确定如何仅对该元素进行样式设置。如果我尝试：

-webkit-filter: blur(5px);
-moz-filter: blur(5px);
-o-filter: blur(5px);
-ms-filter: blur(5px);
filter: blur(5px);

将上述代码放在我的CSS中的background-image下面，它会对整个页面进行样式设置，而不仅仅是背景。有没有办法仅选择图像并将滤镜应用于该图像？或者，有没有办法仅关闭页面上的其他元素的模糊效果？

Answer 1

pen

废除了额外元素的需求，使内容适应文档流而不像其他解决方案那样固定/绝对。

使用以下方式实现

.content {
  /* this is needed or the background will be offset by a few pixels at the top */
  overflow: auto;
  position: relative;
}

.content::before {
  content: "";
  position: fixed;
  left: 0;
  right: 0;
  z-index: -1;

  display: block;
  background-image: url('https://i.imgur.com/lL6tQfy.png');
  background-size:cover;
  width: 100%;
  height: 100%;

  -webkit-filter: blur(5px);
  -moz-filter: blur(5px);
  -o-filter: blur(5px);
  -ms-filter: blur(5px);
  filter: blur(5px);
}

<div class="content">
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
</div>

编辑 如果您想要去除边缘的白色边框，请使用110%的宽度和高度以及-5%的左边和顶部。这样会稍微放大您的背景图像，但边缘不会有实色渗入。感谢Chad Fawcett的建议。

.content {
  /* this is needed or the background will be offset by a few pixels at the top */
  overflow: auto;
  position: relative;
}

.content::before {
  content: "";
  position: fixed;
  top: -5%;
  left: -5%;
  right: -5%;
  z-index: -1;

  display: block;
  background-image: url('https://i.imgur.com/lL6tQfy.png');
  background-size:cover;
  width: 110%;
  height: 110%;

  -webkit-filter: blur(5px);
  -moz-filter: blur(5px);
  -o-filter: blur(5px);
  -ms-filter: blur(5px);
  filter: blur(5px);
}

<div class="content">
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
</div>

Answer 2

查看这个笔记本。

您将需要使用两个不同的容器，一个用于背景图像，另一个用于内容。

在示例中，我创建了两个容器，.background-image和.content。

它们都使用了position: fixed和left: 0; right: 0;进行定位。它们显示的差异来自于为元素设置的不同z-index值。

.background-image {
  position: fixed;
  left: 0;
  right: 0;
  z-index: 1;
  display: block;
  background-image: url('https://i.imgur.com/lL6tQfy.png');
  width: 1200px;
  height: 800px;
  -webkit-filter: blur(5px);
  -moz-filter: blur(5px);
  -o-filter: blur(5px);
  -ms-filter: blur(5px);
  filter: blur(5px);
}

.content {
  position: fixed;
  left: 0;
  right: 0;
  z-index: 9999;
  margin-left: 20px;
  margin-right: 20px;
}

<div class="background-image"></div>
<div class="content">
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis aliquam erat in ante malesuada, facilisis semper nulla semper. Phasellus sapien neque, faucibus in malesuada quis, lacinia et libero. Sed sed turpis tellus. Etiam ac aliquam tortor, eleifend
    rhoncus metus. Ut turpis massa, sollicitudin sit amet molestie a, posuere sit amet nisl. Mauris tincidunt cursus posuere. Nam commodo libero quis lacus sodales, nec feugiat ante posuere. Donec pulvinar auctor commodo. Donec egestas diam ut mi adipiscing,
    quis lacinia mauris condimentum. Quisque quis odio venenatis, venenatis nisi a, vehicula ipsum. Etiam at nisl eu felis vulputate porta.</p>
  <p>Fusce ut placerat eros. Aliquam consequat in augue sed convallis. Donec orci urna, tincidunt vel dui at, elementum semper dolor. Donec tincidunt risus sed magna dictum, quis luctus metus volutpat. Donec accumsan et nunc vulputate accumsan. Vestibulum
    tempor, erat in mattis fringilla, elit urna ornare nunc, vel pretium elit sem quis orci. Vivamus condimentum dictum tempor. Nam at est ante. Sed lobortis et lorem in sagittis. In suscipit in est et vehicula.</p>
</div>