drupal_add_css
Definition
drupal_add_css($path = NULL, $options = NULL, $reset = FALSE)
drupal/includes/common.inc, line 2012
Description
Adds a CSS file to the stylesheet queue.
Modules should always prefix the names of their CSS files with the module name, for example: system-menus.css rather than simply menus.css. Themes can override module-supplied CSS files based on their filenames, and this prefixing helps prevent confusing name collisions for theme developers. See drupal_get_css where the overrides are performed.
If the direction of the current language is right-to-left (Hebrew, Arabic, etc.), the function will also look for an RTL CSS file and append it to the list. The name of this file should have an '-rtl.css' suffix. For example a CSS file called 'name.css' will have a 'name-rtl.css' file added to the list, if exists in the same directory. This CSS file should contain overrides for properties which should be reversed or otherwise different in a right-to-left display.
What does this actually mean? CSS preprocessing is the process of aggregating a bunch of separate CSS files into one file that is then compressed by removing all extraneous white space.
The reason for merging the CSS files is outlined quite thoroughly here: http://www.die.net/musings/page_load_time/ "Load fewer external objects. Due to request overhead, one bigger file just loads faster than two smaller ones half its size."
However, you should *not* preprocess every file as this can lead to redundant caches. You should set $preprocess = FALSE when your styles are only used rarely on the site. This could be a special admin page, the homepage, or a handful of pages that does not represent the majority of the pages on your site.
Typical candidates for caching are for example styles for nodes across the site, or used in the theme.
Parameters
$path (optional) The path to the CSS file relative to the base_path(), e.g., /modules/devel/devel.css.
$options (optional) A string defining the type of CSS that is being added in the $path parameter ('module' or 'theme'), or an associative array of additional options, with the following keys:
- 'type' The type of stylesheet that is being added. Types are: module or theme. Defaults to 'module'.
- 'media' The media type for the stylesheet, e.g., all, print, screen. Defaults to 'all'.
- 'preprocess': Allow this CSS file to be aggregated and compressed if the Optimize CSS feature has been turned on under the performance section. Defaults to TRUE.
Return value
An array of CSS files.
Related topics
Name | Description |
|---|---|
| Input validation | Functions to validate user input. |
Code
function drupal_add_css($path = NULL, $options = NULL, $reset = FALSE) {
static $css = array();
global $language;
// Request made to reset the CSS added so far.
if ($reset) {
$css = array();
}
// Create an array of CSS files for each media type first, since each type needs to be served
// to the browser differently.
if (isset($path)) {
// Construct the options, taking the defaults into consideration.
if (isset($options)) {
if (!is_array($options)) {
$options = array('type' => $options);
}
}
else {
$options = array();
}
$options += array(
'type' => 'module',
'media' => 'all',
'preprocess' => TRUE
);
$media = $options['media'];
$type = $options['type'];
// This check is necessary to ensure proper cascading of styles and is faster than an asort().
if (!isset($css[$media])) {
$css[$media] = array('module' => array(), 'theme' => array());
}
$css[$media][$type][$path] = $options['preprocess'];
// If the current language is RTL, add the CSS file with RTL overrides.
if (defined('LANGUAGE_RTL') && $language->direction == LANGUAGE_RTL) {
$rtl_path = str_replace('.css', '-rtl.css', $path);
if (file_exists($rtl_path)) {
$css[$media][$type][$rtl_path] = $options['preprocess'];
}
}
}
return $css;
}