CSS3 经典教程系列:CSS3 径向渐变(radial-gradient)

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CSS3 经典教程系列:CSS3 径向渐变(radial-gradient)

秋天风景 2013-02-24 22:33:00 浏览569
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  《CSS3 经典教程系列》上篇文章介绍了 linear-gradient(线性渐变),这篇文章向大家介绍 radial-gradient(径向渐变)以及重复渐变(线性重复、径向重复)。在以前,渐变效果和阴影、圆角效果一样都是做成图片,现在 CSS3 可以直接编写  CSS 代码来实现。

 

  CSS3 径向渐变和线性渐变是很相似的,我们首先来看其语法

-moz-radial-gradient([<bg-position> || <angle>,]? [<shape> || <size>,]? <color-stop>, <color-stop>[, <color-stop>]*);
 -webkit-radial-gradient([<bg-position> || <angle>,]? [<shape> || <size>,]? <color-stop>, <color-stop>[, <color-stop>]*);

  除了您已经在线性渐变中看到的起始位置,方向,和颜色,径向梯度允许你指定渐变的形状(圆形或椭圆形)和大小(最近端,最近角,最远端,最远角,包含或覆盖 (closest-side, closest-corner, farthest-side, farthest-corner, contain or cover))。 颜色起止(Color stops):就像用线性渐变,你应该沿着渐变线定义渐变的起止颜色。下面为了更好的理解其具体的用法,我们主要通过不同的示例来对比CSS3径向渐变的具体用法

  示例一:

background: -moz-radial-gradient(#ace, #f96, #1E90FF);
background: -webkit-radial-gradient(#ace, #f96, #1E90FF);

  效果:

  

  示例二:

background: -moz-radial-gradient(#ace 5%, #f96 25%, #1E90FF 50%);
background: -webkit-radial-gradient(#ace 5%, #f96 25%, #1E90FF 50%);

  效果如下:

  

  从以上俩个示例的代码中发现,他们起止色想同,但就是示例二定位了些数据,为什么会造成这么大的区别呢?其实在径向渐变中虽然具有相同的起止色,但是在没有设置位置时,其默认颜色为均匀间隔,这一点和我们前面的线性渐变是一样的,但是设置了渐变位置就会按照渐变位置去渐变,这就是我们示例一和示例的区别之处:虽然圆具有相同的起止颜色,但在示例一为默认的颜色间隔均匀的渐变,而示例二每种颜色都有特定的位置。

  示例三:

background: -moz-radial-gradient(bottom left, circle, #ace, #f96, #1E90FF);
background: -webkit-radial-gradient(bottom left, circle, #ace, #f96, #1E90FF);

  效果如下:

  

  示例四:

background: -moz-radial-gradient(bottom left, ellipse, #ace, #f96, #1E90FF);
background: -webkit-radial-gradient(bottom left, ellipse, #ace, #f96, #1E90FF);

  效果如下:

  

  示例三和示例四我们从效果中就可以看出,其形状不一样,示例三程圆形而示例四程椭圆形状,也是就是说他们存在形状上的差异。然而我们在回到两个示例的代码中,显然在示例三中设置其形状为 circle,而在示例四中 ellipse,换而言之在径向渐变中,我们是可以设置其形状的。

  示例五:

background: -moz-radial-gradient(ellipse closest-side, #ace, #f96 10%, #1E90FF 50%, #f96);
background: -webkit-radial-gradient(ellipse closest-side, #ace, #f96 10%, #1E90FF 50%, #f96);

  效果如下:

  

  示例六:

background: -moz-radial-gradient(ellipse farthest-corner, #ace, #f96 10%, #1E90FF 50%, #f96);
background: -webkit-radial-gradient(ellipse farthest-corner, #ace, #f96 10%, #1E90FF 50%, #f96);

  效果如下:

  

  从示例五和示例六中的代码中我们可以清楚知道,在示例五中我人应用了closest-side而在示例六中我们应用了farthest-corner。这样我们可以知道在径向渐变中我们还可以为其设置大小(Size):size的不同选项(closest-side, closest-corner, farthest-side, farthest-corner, contain or cover)指向被用来定义圆或椭圆大小的点。 示例:椭圆的近边VS远角 下面的两个椭圆有不同的大小。示例五是由从起始点(center)到近边的距离设定的,而示例六是由从起始点到远角的的距离决定的。

  示例七:

background: -moz-radial-gradient(circle closest-side, #ace, #f96 10%, #1E90FF 50%, #f96);
background: -webkit-radial-gradient(circle closest-side, #ace, #f96 10%, #1E90FF 50%, #f96);

  效果如下:

  

  示例八:

background: -moz-radial-gradient(circle farthest-side, #ace, #f96 10%, #1E90FF 50%, #f96);
background: -webkit-radial-gradient(circle farthest-side, #ace, #f96 10%, #1E90FF 50%, #f96);

  效果如下:

  

  示例七和示例八主要演示了圆的近边VS远边 ,示例七的圆的渐变大小由起始点(center)到近边的距离决定,而示例八的圆则有起始点到远边的距离决定。

  示例九:

background: -moz-radial-gradient(#ace, #f96, #1E90FF);
background: -webkit-radial-gradient(#ace, #f96, #1E90FF);

  效果如下:

  

  示例十:

background: -moz-radial-gradient(contain, #ace, #f96, #1E90FF);
background: -webkit-radial-gradient(contain, #ace, #f96, #1E90FF);

  效果如下:

  

  示例九和示例十演示了包含圆 。在这里你可以看到示例九的默认圈,同一渐变版本,但是被包含的示例十的圆。

  最后我们在来看两个实例一个是应用了中心定位和full sized,如下所示:

/* Firefox 3.6+ */ 
 background: -moz-radial-gradient(circle, #ace, #f96); 
 /* Safari 4-5, Chrome 1-9 */ 
 /* Can't specify a percentage size? Laaaaaame. */ 
 background: -webkit-gradient(radial, center center, 0, center center, 460, from(#ace), to(#f96)); 
 /* Safari 5.1+, Chrome 10+ */ 
 background: -webkit-radial-gradient(circle, #ace, #f96);   

  效果如下:

  

  下面这个实例应用的是Positioned, Sized,请看代码和效果:

/* Firefox 3.6+ */ 
/* -moz-radial-gradient( [ || ,]? [ || ,]? , [, ]* ) */
background: -moz-radial-gradient(80% 20%, closest-corner, #ace, #f96); 
/* Safari 4-5, Chrome 1-9 */
background: -webkit-gradient(radial, 80% 20%, 0, 80% 40%, 100, from(#ace), to(#f96)); 
/* Safari 5.1+, Chrome 10+ */
background: -webkit-radial-gradient(80% 20%, closest-corner, #ace, #f96);

  效果如下:

  

  到此关于 CSS3 的两种渐变方式我们都介绍完了。再浪费大家一点时间,我们看看CSS3 重复渐变(Repeating Gradient)的应用

  如果您想重复一个渐变,您可以使用-moz-repeating-linear-gradient(重复线性渐变)和-moz-repeating-radial-gradient(重复径向渐变)。 在下面的例子,每个实例都指定了两个起止颜色,并无限重复。

background: -moz-repeating-radial-gradient(#ace, #ace 5px, #f96 5px, #f96 10px);
background: -webkit-repeating-radial-gradient(#ace, #ace 5px, #f96 5px, #f96 10px);
background: -moz-repeating-linear-gradient(top left -45deg, #ace, #ace 5px, #f96 5px, #f96 10px);
background: -webkit-repeating-linear-gradient(top left -45deg, #ace, #ace 5px, #f96 5px, #f96 10px);

  效果:

           

  有关于CSS3渐变的东西就完了,大家看完了肯定会想,他主要用在哪些方面呢?这个说起来就多了,最简单的就是制作背景,我们还可以应用其制作一些漂亮的按钮,还可以用他来制作patterns,我在这里列出几种制作patterns的示例代码吧:

  HTML代码:

<ul>
   <li class="gradient gradient1"></li>
   <li class="gradient gradient2"></li>
   <li class="gradient gradient3"></li>
   <li class="gradient gradient4"></li>
   <li class="gradient gradient5"></li>
   <li class="gradient gradient6"></li>
</ul>

  CSS 代码:

ul {
  overflow: hidden;
  margin-top: 20px;
}
li{
  width: 150px;
  height: 80px;
  margin-bottom: 10px;
  float: left;
  margin-right: 5px;
  background: #ace;
  /*Controls the size*/
  -webkit-background-size: 20px 20px;
  -moz-background-size: 20px 20px;
  background-size: 20px 20px; 
}
    
li.gradient1 {
  background-image: -webkit-gradient(
    linear,
    0 100%, 100% 0,
    color-stop(.25, rgba(255, 255, 255, .2)), 
    color-stop(.25, transparent),
    color-stop(.5, transparent), 
    color-stop(.5, rgba(255, 255, 255, .2)),
    color-stop(.75, rgba(255, 255, 255, .2)), 
    color-stop(.75, transparent),
    to(transparent)
    );
  background-image: -moz-linear-gradient(
    45deg, 
    rgba(255, 255, 255, .2) 25%, 
    transparent 25%,
    transparent 50%, 
    rgba(255, 255, 255, .2) 50%, 
    rgba(255, 255, 255, .2) 75%,
    transparent 75%, 
    transparent
    );
  background-image: -o-linear-gradient(
    45deg, 
    rgba(255, 255, 255, .2) 25%, 
    transparent 25%,
    transparent 50%, 
    rgba(255, 255, 255, .2) 50%, 
    rgba(255, 255, 255, .2) 75%,
    transparent 75%, 
    transparent
  );
  background-image: linear-gradient(
    45deg, 
    rgba(255, 255, 255, .2) 25%, 
    transparent 25%,
    transparent 50%, 
    gba(255, 255, 255, .2) 50%, 
    rgba(255, 255, 255, .2) 75%,
    transparent 75%, 
    transparent
    );
}

li.gradient2 {
   background-image: -webkit-gradient(linear, 0 0, 100% 100%,
      color-stop(.25, rgba(255, 255, 255, .2)), color-stop(.25, transparent),
      color-stop(.5, transparent), color-stop(.5, rgba(255, 255, 255, .2)),
      color-stop(.75, rgba(255, 255, 255, .2)), color-stop(.75, transparent),
      to(transparent));
   background-image: -moz-linear-gradient(-45deg, rgba(255, 255, 255, .2) 25%, transparent 25%,
      transparent 50%, rgba(255, 255, 255, .2) 50%, rgba(255, 255, 255, .2) 75%,
      transparent 75%, transparent);
   background-image: -o-linear-gradient(-45deg, rgba(255, 255, 255, .2) 25%, transparent 25%,
      transparent 50%, rgba(255, 255, 255, .2) 50%, rgba(255, 255, 255, .2) 75%,
      transparent 75%, transparent);
   background-image: linear-gradient(-45deg, rgba(255, 255, 255, .2) 25%, transparent 25%,
      transparent 50%, rgba(255, 255, 255, .2) 50%, rgba(255, 255, 255, .2) 75%,
      transparent 75%, transparent);
}
    
li.gradient3 {
  background-image: -webkit-gradient(linear, 0 0, 0 100%, color-stop(.5, rgba(255, 255, 255, .2)), color-stop(.5, transparent), to(transparent));
  background-image: -moz-linear-gradient(rgba(255, 255, 255, .2) 50%, transparent 50%, transparent);
  background-image: -o-linear-gradient(rgba(255, 255, 255, .2) 50%, transparent 50%, transparent);
  background-image: linear-gradient(rgba(255, 255, 255, .2) 50%, transparent 50%, transparent);
}
    
li.gradient4 {
  background-image: -webkit-gradient(linear, 0 0, 100% 0, color-stop(.5, rgba(255, 255, 255, .2)), color-stop(.5, transparent), to(transparent));
  background-image: -moz-linear-gradient(0deg, rgba(255, 255, 255, .2) 50%, transparent 50%, transparent);
  background-image: -o-linear-gradient(0deg, rgba(255, 255, 255, .2) 50%, transparent 50%, transparent);
  background-image: linear-gradient(0deg, rgba(255, 255, 255, .2) 50%, transparent 50%, transparent);
}
    
li.gradient5 {
  background-image: -webkit-gradient(linear, 0 0, 100% 100%, color-stop(.25, #555), color-stop(.25, transparent), to(transparent)),
      -webkit-gradient(linear, 0 100%, 100% 0, color-stop(.25, #555), color-stop(.25, transparent), to(transparent)),
      -webkit-gradient(linear, 0 0, 100% 100%, color-stop(.75, transparent), color-stop(.75, #555)),
      -webkit-gradient(linear, 0 100%, 100% 0, color-stop(.75, transparent), color-stop(.75, #555));
  background-image: -moz-linear-gradient(45deg, #555 25%, transparent 25%, transparent),
     -moz-linear-gradient(-45deg, #555 25%, transparent 25%, transparent),
     -moz-linear-gradient(45deg, transparent 75%, #555 75%),
     -moz-linear-gradient(-45deg, transparent 75%, #555 75%);
  background-image: -o-linear-gradient(45deg, #555 25%, transparent 25%, transparent),
     -o-linear-gradient(-45deg, #555 25%, transparent 25%, transparent),
     -o-linear-gradient(45deg, transparent 75%, #555 75%),
     -o-linear-gradient(-45deg, transparent 75%, #555 75%);
  background-image: linear-gradient(45deg, #555 25%, transparent 25%, transparent),
    linear-gradient(-45deg, #555 25%, transparent 25%, transparent),
    linear-gradient(45deg, transparent 75%, #555 75%),
    linear-gradient(-45deg, transparent 75%, #555 75%);
}
    
li.gradient6 {
  background-image: -webkit-gradient(linear, 0 0, 0 100%, color-stop(.5, transparent), color-stop(.5, rgba(200, 0, 0, .5)), to(rgba(200, 0, 0, .5))),
     -webkit-gradient(linear, 0 0, 100% 0, color-stop(.5, transparent), color-stop(.5, rgba(200, 0, 0, .5)), to(rgba(200, 0, 0, .5)));
  background-image: -moz-linear-gradient(transparent 50%, rgba(200, 0, 0, .5) 50%, rgba(200, 0, 0, .5)),
     -moz-linear-gradient(0deg, transparent 50%, rgba(200, 0, 0, .5) 50%, rgba(200, 0, 0, .5));
  background-image: -o-linear-gradient(transparent 50%, rgba(200, 0, 0, .5) 50%, rgba(200, 0, 0, .5)),
     -o-linear-gradient(0deg, transparent 50%, rgba(200, 0, 0, .5) 50%, rgba(200, 0, 0, .5));
  background-image: linear-gradient(transparent 50%, rgba(200, 0, 0, .5) 50%, rgba(200, 0, 0, .5)),
     linear-gradient(0deg, transparent 50%, rgba(200, 0, 0, .5) 50%, rgba(200, 0, 0, .5));
}

  效果:

  

  不错的效果吧,当然感兴趣的朋友可以到这里学习制作更多的不同效果。

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本文链接:CSS3入门教程:CSS3径向渐变(整理自:W3CPLUS

编译来源:梦想天空 ◆ 关注Web前端开发技术 ◆ 分享网页设计资源

作者:山边小溪
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