automatically css sprite.
I have written posts “css sprite best practices” to introduce the idea that the css_sprite gem follows.
otaviofcs wrote a brazilian version to introduce the css_sprite gem, check it here and he also build a demo
css sprite generates css_sprite image and css files automatically for you follow the conventions as follows.
| images under css_sprite directory | class name in css_sprite css |
|---|---|
| twitter_icon.png | .twitter_icon |
| facebook_icon.png | .facebook_icon |
| hotmail-logo.png | .hotmail-logo |
| gmail-logo.png | .gmail-logo |
| icons/twitter_icon.png | .icons .twitter_icon |
| widget/icons/twitter_icon.png | .widget .icons .twitter_icon |
| twitter_icon_hover.png | .twitter_icon:hover |
| twitter-icon-hover.png | .twitter-icon:hover |
| logos_hover/gmail_logo.png | .logos:hover .gmail_logo |
| logos-hover/gmail-logo.png | .logos:hover .gmail-logo |
| gmail_logo_active.png | .gmail_logo.active |
| gmail-logo-active.png | .gmail-logo.active |
| logos_active/gmail_logo.png | .logos.active .gmail_logo |
| logos-active/gmail-logo.png | .logos.active .gmail-logo |
css_sprite directory is the directory whose name is "css_sprite" or
"css_sprite" suffixed under app/assets/images directory.
css_sprite image is the image file automatically generated under
app/assets/images directory.
css_sprite css is the css file automatically generated under
app/assets/stylesheets directory.
css_sprite depends on the mini_magick gem
css_sprite also depends on the optipng tool as default image optimization, but you can use any other image optimization tool, check the Configuration section.
If you use the default optipng tool, please make sure it is successfully installed on your system.
install css_sprite as a gem:
gem install css_sprite
1. create a directory whose name is css_sprite or ends with css_sprite (e.g. widget_css_sprite) under app/assets/images directory
2. if you css_sprite in rails2 projects, you should add css_sprite task in Rakefile
require 'css_sprite'
If you use rails3, you can skip this step too
3. define config/css_sprite.yml, it is not necessary by default.
4. start css_sprite server
rake css_sprite:start
5. put any images which you need to do the css sprite under the css_sprite directory, then you will see the automatically generated css sprite image and css files.
6. include the stylesheet in your view page
<%= stylesheet_link_tag 'css_sprite' %>
You can stop the css_sprite server by rake css_sprite:stop
You can restart the css_sprite server by rake css_sprite:start
Or you can just do the css sprite manually by rake css_sprite:build
There is no need to do any configurations by default for Rails 3.1 or higher projects. If you want some customizations as follows, you need to define config/css_sprite.yml file.
engine: css
image_path: public/images
stylesheet_path: public/stylesheets
css_images_path: images
source_images_path: app/sprites
css_sprite saves the css sprite image as a png file by default. You can change it to gif or any other format like
format: GIF
css_sprite generate background: url('css_sprite.png') no-repeat by default, if you prefer background: asset-url('css_sprite.png') no-repeat, you can change it as follows
use_asset_url: true
css_sprite generates css.scss file by default. You can change it to pure css or sass as you like.
engine: css
engine: css.sass
css_sprite allows to do optimization to generated css_sprite.png, you can use default optipng with optimization level 2.
optimization: true
Or you can change it to any image optimization command.
optimization: optipng -o 7
For css or scss
suffix:
button: |
text-indent: -9999px;
display: block;
cursor: pointer;
font-size: 0;
line-height: 15px;
border: 0;
outline: 0;
icon: |
text-indent: -9999px;
cursor: pointer;
For sass
engine: sass
suffix:
button: |
text-indent: -9999px
display: block
cursor: pointer
font-size: 0
line-height: 15px
border: 0
outline: 0
icon: |
text-indent: -9999px
cursor: pointer
engine defines css.scss (default), pure css or sass file to generate.
suffix defines the customization styles for specified images.
The customization above means if your image filename is button suffixed (e.g. post_button.png), the corresponding class .post_button has the additional style with (outline: 0; border: 0; and so on), if your image filename is icon suffixed (e.g. twitter_icon.png), the correspondiing class .twitter_icon has the additional style with (text-indent: -9999px; cursor: pointer)
css_sprite follows the conventions that images are under
app/assets/images directory and css files are under
app/assets/stylesheets, but you can change them.
image_path: public/images
stylesheet_path: public/stylesheets
source_images_path: app/sprites
By default, source_images_path and image_path are app/assets/images and
stylesheet_path is app/assets/stylesheets.
I built an example
images are under app/assets/images/css_sprite/
generated css sprite image is at app/assets/images/css_sprite.png
genereated css file is at app/assets/stylesheets/css_sprite.css
$ cd example
$ rake css_sprite:build
$ open index.html
Copyright (c) 2009 - 2013 [Richard Huang] [email protected], released under the MIT license