CSS uses Sprites technology to achieve rounded corners_Experience exchange

First of all, let’s briefly talk about what Sprites are. Sprites are a web image application processing method. It allows you to include all the scattered pictures involved in a page into one big picture, so that when the page is accessed, the loaded pictures will not be displayed one by one as before. . For the current popular network speed, the loading time required for a single image not exceeding 200KB is basically the same, so there is no need to worry about this issue.

Step 1: Create our Sprite

Use tools such as PS to synthesize the picture as shown in the picture (distinguished by a red line of one pixel)

Step 2: Write HTML code

First, we will give the container div a .roundedBox class:

Copy code The code is as follows:

Now, we have to add four more divs, which will be used later when creating rounded corners. Then a class .corner must be loaded for each, and a class must be identified to specify the position of their grid.

Copy code The code is as follows:

My content in roundedBox Type 1

Step 3: Write CSS styles

Absolutely positioned elements are usually positioned according to their relatively positioned parent elements. If the parent element cannot be defined, then it will go to the most recently relatively positioned parent element, up to the body tag.

Let's define all the fillets first

All fillets must be absolutely positioned and have a height and width specified. The width and height of my fillet definition are both 17px.

Copy code The code is as follows:

.corner{position:absolute;width:17px;height:17px;}

Now start defining the div container style:

Copy code The code is as follows:

.roundedBox {position:relative;}

Within any element defined with class .roundedBox, absolutely positioned elements will be positioned relative to this element, not the body tag. We also have to set some padding values. If not set, the rounded corners will cover our text, which is definitely not the effect we want. Important: The top and bottom padding values ​​must be equal to the height of the fillet. The left and right padding values ​​must be equivalent to the width of the fillet. As you already know, the width and height of my fillets are equal, so the padding values ​​for the four corners are also equal:

Copy code The code is as follows:

.roundedBox {position:relative; padding:17px; margin:10px 0;}

Let us make a separate definition for no rounded corners

We will set the absolute positioning of each rounded corner and position the background image (according to our sprite):

Copy code The code is as follows:

.roundedBox {position:relative; padding:17px; margin:10px 0;}
.corner {position:absolute; width:17px; height:17px;}
.topLeft {top:0; left:0; background-position:-1px -1px;}
.topRight {top:0; right:0; background-position:-19px -1px;}
.bottomLeft {bottom:0; left:0; background-position:-1px -19px;}
.bottomRight {bottom:0; right:0; background-position:-19px -19px;}

Finally, match a background color to #type1 so that it blends into the rounded corners of the sprite:

Copy code The code is as follows:

#type1 {background-color:#CCDEDE;}
#type1 .corner {background-image:url(../image/corners.gif);}

All code:

Copy code The code is as follows:

ttp://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
http://www.w3.org/1999/xhtml">

    My content in roundedBox Type 1