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Summary of CSS knowledge (7)

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Aug 15, 2016 pm 04:49 PM

Common CSS styles

5. Background style

　1)Background color

　　background-color : transparent | color

　Common values: ①English words, ②Hex, ③RGB or RGBA

　 In addition, there is also a gradient color

　　Gradient color (gradient) is divided into linear gradient(linear) and radial gradient(radial)

　　Linear gradient: background: linear-gradient(direction, color1, color2, ...);

　 When the first parameter is omitted, it defaults to "180deg", which is equivalent to "to bottom".

　　The second and third parameters represent the starting point and end point of the color, and can have multiple color values. (You can add a percentage after the color value to indicate the percentage of the total background color area that this color accounts for)

　Example source code:

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.linear</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">100px</span>;<span style="color: #ff0000;">
    background</span>:<span style="color: #0000ff;">linear-gradient(to right,red 30%,yellow)</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="linear"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

　Effect:

　　　Radial gradient: background: radial-gradient(center, shape, size, color, color, ...);

　 You can specify the center, shape (prototype or ellipse), and size of the gradient.

　By default, the center of the gradient is center (representing the center point), the shape of the gradient is ellipse (representing an ellipse), and the size of the gradient is farthest-corner (representing the farthest corner).

　Example source code:

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.radial</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">100px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">100px</span>;<span style="color: #ff0000;">
    background</span>:<span style="color: #0000ff;">radial-gradient(circle, red, yellow, green)</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="radial"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

Effect:

　2)Background picture

　　background-image : none | url(url)

　Example source code:

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.image</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">142px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">55px</span>;<span style="color: #ff0000;">
    background-image</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif)</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="image"</span><span style="color: #0000ff;">><span style="color: #000000;">后面的是背景</span></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

　Effect:

What’s behind is the background

　3)Background tiling method

　　background-repeat : repeat | no-repeat | repeat-x | repeat-y

　Example 1 (repeat-x) Source code:

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.x</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">300px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background-image</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif)</span>;<span style="color: #ff0000;">
    background-repeat</span>:<span style="color: #0000ff;">repeat-x</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="x"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

Effect:

　Example 2 (repeat-y) Source code:

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.y</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">300px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background-image</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif)</span>;<span style="color: #ff0000;">
    background-repeat</span>:<span style="color: #0000ff;">repeat-y</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="y"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

　Effect:

　　4）背景定位

　　　　background-position : 左对齐方式上对齐方式

　　　　①background-position:left bottom;

　　　　②background-position:50% 50px;

　　例子源代码：

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.position</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">300px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background-image</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif)</span>;<span style="color: #ff0000;">
    background-repeat</span>:<span style="color: #0000ff;">no-repeat</span>;<span style="color: #ff0000;">
    background-position</span>:<span style="color: #0000ff;">left bottom</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="position"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

　　效果：

　　6）背景原点

　　　　设置元素背景图片的原始起始位置。必须保证背景是background-repeat为no-repeat，此属性才会生效。

　　　　background-origin : border-box | padding-box | content-box;

　　7）背景的显示区域

　　　　设定背景图像向外裁剪的区域。

　　　　background-clip : border-box | padding-box | content-box;

　　8）背景尺寸

　　　　设置背景图片的大小，以长度值或百分比显示，还可以通过cover和contain来对图片进行伸缩。

　　　　background-size : length | percentage | cover | contain;

　　　　length : 设置背景图像的高度和宽度。

　　　　percentage : 以父元素的百分比来设置背景图像的宽度和高度。

　　　　cover : 把背景图像扩展至足够大，以使背景图像完全覆盖背景区域；但是背景图像的某些部分也许无法显示在背景定位区域中。

　　　　contain : 把图像图像扩展至最大尺寸，以使其宽度和高度完全适应内容区域。

　　例子源代码：

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.size1</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">142px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">55px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background-image</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif)</span>;<span style="color: #ff0000;">
    background-repeat</span>:<span style="color: #0000ff;">no-repeat</span>;
}<span style="color: #800000;">
.size2</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">142px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">55px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background-image</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif)</span>;<span style="color: #ff0000;">
    background-repeat</span>:<span style="color: #0000ff;">no-repeat</span>;<span style="color: #ff0000;">
    background-size</span>:<span style="color: #0000ff;">100px 30px</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span><span style="color: #000000;">
    原大小：
    </span><span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="size1"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span><span style="color: #000000;">
    改变大小后：
    </span><span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="size2"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span></span>

　　效果：

原大小：

改变大小后：

　　9）背景样式缩写

　　　　background : 背景色背景图片背景平铺方式背景定位

　　例子源代码：

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.bg</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">100px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background</span>:<span style="color: #0000ff;">#ccc url(http://www.cnblogs.com/images/logo_small.gif) no-repeat center center</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bg"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

　　效果：

　　10）多重背景

　　　　一个元素可以设置多重背景图像，每组属性间使用逗号分隔。

　　　　多重背景图之间存在着重叠关系，前面的背景图会覆盖在后面的背景图之上。

　　　　background : background-image background-repeat background-attachment background-position/background-size

　　　　　　　　　　　background-origin background-clip background-color

　　　　background-image：指定对象的背景图像。可以是真实图片路径或使用渐变创建的“背景图像”。

　　　　background-repeat：指定对象的背景图像如何铺排填充。

　　　　background-attachment：指定对象的背景图像是随对象内容滚动还是固定的。

　　　　background-position：指定对象的背景图像位置。

　　　　background-size：指定对象的背景图像的尺寸大小。

　　　　background-origin：指定对象的背景图像显示的原点。

　　　　background-clip：指定对象的背景图像向外裁剪的区域。

　　　　background-color：指定对象的背景颜色。

　　　　*注意：background-color只能设置一次，且由于写在前面的背景会叠在之后的背景之上，所以背景色通常都定义在最后一组上，避免背景色将图像盖住。

　　例子源代码：

<span style="color: #008000;">/*</span><span style="color: #008000;"> CSS代码 </span><span style="color: #008000;">*/</span><span style="color: #800000;">
.bg2</span>{<span style="color: #ff0000;">
    width</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    height</span>:<span style="color: #0000ff;">200px</span>;<span style="color: #ff0000;">
    border</span>:<span style="color: #0000ff;">1px solid #000</span>;<span style="color: #ff0000;">
    background</span>:<span style="color: #0000ff;">url(http://www.cnblogs.com/images/logo_small.gif) no-repeat scroll 10px 20px/115px 52px content-box padding-box,<br>　　　　　　　　url(http://www.cnblogs.com/images/logo_small.gif)  no-repeat scroll 30px 40px/115px 52px content-box padding-box,<br>　　　　　　　　url(http://www.cnblogs.com/images/logo_small.gif)  no-repeat scroll 50px 60px/115px 52px content-box padding-box #ccc</span>;
}

<span style="color: #008000;"><!--</span><span style="color: #008000;"> HTML代码 </span><span style="color: #008000;">--></span>
<span style="color: #0000ff;"><span style="color: #800000;">body</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">div </span><span style="color: #ff0000;">class</span><span style="color: #0000ff;">="bg2"</span><span style="color: #0000ff;">></span><span style="color: #800000;">div</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">body</span><span style="color: #0000ff;">></span></span></span>

　　效果：

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