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This chapter will introduce to you how to use image stitching technology in CSS? It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
1. Image stitching
Image stitching is a collection of single images.
Web pages with many images may take a long time to load and generate requests to multiple servers.
Using image stitching will reduce the number of server requests and save bandwidth.
2. Image splicing - simple example
Instead of using three independent images, it is better to use this single image ("img_navsprites. gif"):
With CSS, we can display only the part of the image we need.
In the following example CSS specifies part of the image that displays "img_navsprites.gif":
img.home { width:46px; height:44px; background:url(img_navsprites.gif) 0 0; }
Example analysis:
-Because it cannot be empty, the src attribute only defines a small transparent image. The image displayed will be the background image we specified in CSS
Width: 46px; Height: 44px; - Define that part of the image we use
background:url(img_navsprites.gif) 0 0; - Define the background image and its position (left 0px, top 0px)
This is the easiest way to use image stitching , now we use links and hover effects.
3. Image stitching - Create a navigation list
We want to use stitched images ("img_navsprites.gif") to create a navigation list.
We will use an HTML list because it can be linked and also supports background images:
#navlist{position:relative;} #navlist li{margin:0;padding:0;list-style:none;position:absolute;top:0;} #navlist li, #navlist a{height:44px;display:block;} #home{left:0px;width:46px;} #home{background:url('img_navsprites.gif') 0 0;} #prev{left:63px;width:43px;} #prev{background:url('img_navsprites.gif') -47px 0;} #next{left:129px;width:43px;} #next{background:url('img_navsprites.gif') -91px 0;}
Example analysis:
#navlist{position :relative;} - Position sets relative positioning, making the absolute positioning inside
navlist li{margin:0;padding:0;list-style:none;position:absolute;top :0;} - margin and padding are set to 0, the list style is removed, and all list items are absolutely positioned
#navlist li, #navlist a{height:44px;display:block ;} - The height of all images is 44px
Now onto the positioning and styling of each specific section:
#home{left:0px ;width:46px;} - Position the image to the far left and the width of the image is 46px
#home{background:url(img_navsprites.gif) 0 0;} - Define the background Image and its position (0px left, 0px top)
#prev{left:63px;width:43px;} - positioned 63px on the right (#home width 46px between items some extra space) with a width of 43px.
#prev{background:url('img_navsprites.gif') -47px 0;} - Define the background image 47px to the right (#home width 46px 1px of the divider)
#next{left:129px;width:43px;}- The right position is 129px (#prev 63px #prev width is 43px and the remaining space), the width is 43px.
#next{background:url('img_navsprites.gif') no-repeat -91px 0;} - Define 91px on the right side of the background image (#home 46px 1px dividing line #prev width 43px 1px dividing line)
4. Image stitching - hover effect
Now, we want to add a hover effect to our navigation list Stop effect.
:hover selector is used to display the effect when the mouse is hovering over the element.
Tip: The :hover selector can be applied to all elements.
Our new image ("img_navsprites_hover.gif") contains three navigation images and three images:
Because this is a single image, Instead of 6 separate image files, there will be no lazy loading when the user hovers over the image.
We only add three lines of code to add the hover effect:
#home a:hover{background: url('img_navsprites_hover.gif') 0 -45px;} #prev a:hover{background: url('img_navsprites_hover.gif') -47px -45px;} #next a:hover{background: url('img_navsprites_hover.gif') -91px -45px;}
Example analysis:
Since the list item contains a link, we can use :hover pseudo-class
#home a:hover{background: transparent url(img_navsprites_hover.gif) 0 -45px;} - For all three hover images, we specify the same background Position, just 45px each further down
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