CSS3怎么给背景图片添加动态变色效果 css3背景图片自适应

在之前的文章《利用CSS3创建炫酷的三角背景图像》中，我们给大家介绍了一种创建炫酷三角背景图像的方法，感兴趣的朋友可以去了解一下~

而下面本文再给大家介绍一种创建炫酷背景图像方法，带大家了解一下如何利用CSS3创建变色背景图像动画，让你的网页更吸引人！

我们先来看看效果图

下面我们来研究一下是怎么实现这个效果的：

首先我们不创建标签，直接在body标签上设置背景图片

body {
   background-image: url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center;
}

怎么将图片变色呢？这就需要在背景图片上添加一个颜色层作为覆盖层，这个可以利用linear-gradient()函数实现：

background-image: 
           linear-gradient(4deg, rgba(0,255,254,0.3) 50%, rgba(0,255,254,0.3) 100%),
   url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");

此时这个还是静态效果，怎么实现不断变色的动态效果？我们可以利用@keyframes和animation属性来实现–添加动画效果：

• 利用animation属性设置动画名称、播放时间、播放次数等：

body {
  background-image: url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center;
  animation-name: background-overlay-animation;
  animation-duration: 5s;
	animation-iteration-count: infinite;
	animation-direction: alternate;
	animation-timing-function: linear;
}

• 利用@keyframes定义每一帧动画：

@keyframes background-overlay-animation {
  0%   {
      background-image: 
        linear-gradient(4deg, rgba(255,78,36,0.3) 50%, rgba(255,78,36,0.3) 100%), 
		url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  25%  {
      background-image: 
         linear-gradient(4deg, rgba(213,49,127,0.3) 50%, rgba(213,49,127,0.3) 100%), 
		 url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  50%  {
    background-image: 
       linear-gradient(4deg, rgba(36,182,255,0.3) 50%, rgba(36,182,255,1) 100%),
     url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  100% {
    background-image: 
        linear-gradient(4deg, rgba(0,255,254,0.3) 50%, rgba(0,255,254,0.3) 100%),
        url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
}

下面给出完整代码：

@keyframes background-overlay-animation {
  0%   {
      background-image: 
        linear-gradient(4deg, rgba(255,78,36,0.3) 50%, rgba(255,78,36,0.3) 100%), 
		url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  25%  {
      background-image: 
         linear-gradient(4deg, rgba(213,49,127,0.3) 50%, rgba(213,49,127,0.3) 100%), 
		 url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  50%  {
    background-image: 
       linear-gradient(4deg, rgba(36,182,255,0.3) 50%, rgba(36,182,255,1) 100%),
     url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  100% {
    background-image: 
        linear-gradient(4deg, rgba(0,255,254,0.3) 50%, rgba(0,255,254,0.3) 100%),
        url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
}

@-webkit-keyframes background-overlay-animation {   /* 兼容谷歌浏览器*/
  0%   {
      background-image: 
        linear-gradient(4deg, rgba(255,78,36,0.3) 50%, rgba(255,78,36,0.3) 100%)
        url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  25%  {
      background-image: 
         linear-gradient(4deg, rgba(213,49,127,0.3) 50%, rgba(213,49,127,0.3) 100%),
        url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  50%  {
    background-image: 
       linear-gradient(4deg, rgba(36,182,255,0.3) 50%, rgba(36,182,255,1) 100%),
     url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
  100% {
    background-image: 
        linear-gradient(4deg, rgba(0,255,254,0.3) 50%, rgba(0,255,254,0.3) 100%),
        url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  }
}

body {
   background-image: url("https://img.php.cn/upload/article/000/000/024/612360451cede816.jpg");
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center;
  animation-name: background-overlay-animation;
  animation-duration: 5s;
	animation-iteration-count: infinite;
	animation-direction: alternate;
	animation-timing-function: linear;
}