Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)

Goal of this article:

1. Master the use of background-origin background origin

Question:

1. To achieve the following effects, use pure DIV CSS, The background origin background-orgin must be used

##Additional instructions:

1. Each photo frame is 500px wide and 500px high, with a border width of 20px and text padding inside. is 20, the size of the border is 20px

2. The photos inside must be implemented according to the background image

Now let’s do the specific operation

1. Prepare the material: root directory Create an images folder and store all relevant material pictures here. The materials are

2. Create it index.html, write the architecture, how to analyze the architecture

Idea analysis:

1. The target is divided into upper and lower parts. Each part is actually displayed with a photo frame (div containing border) photo, so as long as the first implementation is completed, the second part can be copied

2. However, if you look carefully, the display of the above photo and the photo below is still a little different. The background image of the first div is Within the border, and the background image of the div below is within the border

3. Each part is actually a DIV, including the border, and the background image is a photo, which contains a string, the upper and lower parts of the string Contains spacing

According to the analysis, we get the following code

     
  
 
 
谢霆锋年轻的样子，一个字帅
 
 
 
张柏芝年轻的样子，一个字美
 
 
  

3. Write the style, create a css folder, create a new index.css inside, how to write the style inside, as follows Is the analysis idea

Idea analysis:

1. .container *

Idea analysis

1.In order to set all elements in the container Public styles, we can write these public codes into .container * style

So add the following code to index.css:

.container *{ padding:0; margin:0; }

2, .photo photo

1 . According to the requirements, the border is 20px and the dotted line is displayed. The converted code is border-width: 20px; border-style: dashed; the text inside has spacing, so padding: 20px, the font is bold, font-weight: bold, and the color is White color:#fff;

The overall width is 500, so width=500-(2 borders 20 20 2 padding20 20)=420, and the height is also 420, so width: 420, height: 420

So add the following code to index.css:

.photo { width:420px; height: 420px; border-width:20px; border-style: dashed; padding:20px; font-weight:bold; color:#fff; }

3. First photo settings

Because the border of this photo is red, so border-color: red;Then the background is a photo of a handsome guy, and from the effect you can see that the color between the dotted lines is gray, which is #ccc, so background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; The most important thing is that its background image starts from padding, so

background-origin: padding-box; you must pay attention here,In order to make background-origin takes effect,background must set the attribute no-repeat

So add the following code to index.css:

.xtf{ background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; border-color: red; background-origin: padding-box; }

4. Settings for the second photo

Because the border of this photo is orange, border-color: orange; and then the background is a photo of a beautiful woman, and you can see from the effect The color between the dotted lines is gray, which is #ccc, so background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; The most important thing is that its background image starts from the border, so

background-origin: border-box;In order for background-origin to take effect, background must set the attribute no-repeat

So add the following code to index.css:

.zbz{ background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; background-origin: border-box; border-color: orange; }

So far, the entire content of index.css is as follows:

.container *{ padding:0; margin:0; } .photo { width:420px; height: 420px; border-width:20px; border-style: dashed; padding:20px; font-weight:bold; color:#fff; } .xtf{ background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; border-color: red; background-origin: padding-box; } .zbz{ background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; background-origin: border-box; border-color: orange; }

Then introduce index.css into index.html

      
  
 
 
谢霆锋年轻的样子，一个字帅
 
 
 
张柏芝年轻的样子，一个字美
 
 
  

The running effect is as follows:

So far, we have achieved all the requirements

In fact, the value of background-origin can be Set it to border-box, padding-box, or content-box. In this way, the background origin is based on the content. We can try

Let’s modify the photo settings of handsome guy Xie

.xtf{ background:#ccc url(../images/Background-orgin in CSS3 implements photo display effect with photo frame - case analysis (code example)) no-repeat; border-color: red; background-origin: content-box;/**修改成content-box**/ }

运行结果为：

我们就发现背景图片按照内容为原点显示了

总结：

1、学习了背景原点background-origin的用法，它有3个类型，

一个是border-box:背景图片以边框为起始点

一个是padding-box：背景图片以padding为起始点

一个是content-box：背景图片以内容为起始点

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