CSS Pre-Processing¶

The “Plone theming suite” includes the following CSS pre-processors tools supported:

LESS¶

LESS extends CSS with dynamic behavior such as variables, mixins, operations and functions. LESS runs on both the client-side (Chrome, Safari, Firefox) and server-side.

The LESS is support into Plone.

Note

You can find more information about LESS at http://lesscss.org/

collective.lesscss¶

The collective.lesscss package integrates the LESS CSS pre-processor with Plone.

This package clone the portal_css tool behavior, extending it to meet both client-side and server-side LESS resources compiling methods.

It adds a portal_less tool to the portal, enables an import/export GS profile lessregistry.xml file, overrides the default Products.ResourceRegistries viewlet by adding the LESS resources part for the <head> tag.

Adding LESS resources¶

This package is intended to be used in conjunction with an user defined Plone Theme package. As a developer, you can include as many LESS resources as you may need to build your theme. You can add LESS resources using a GS profile named lessregistry.xml. The syntax is cloned from cssregistry.xml profile:

<?xml version="1.0"?>
<object name="portal_less" meta_type="LESS Stylesheets Registry">
  <stylesheet title="++bootstrap++less/bootstrap.less" authenticated="False"
    enabled="on" id="++bootstrap++less/bootstrap.less" rendering="link"/>
</object>

Control Panel¶

You can manage the way the LESS resources compile by accessing the LESS resources configlet located at the Site Setup. By default, client-side LESS resources compile mode and minification are enabled.

You can access to the Plone LESS control panel following the steps:

at the top right corner of the page click on the Admin drop down menu
choose Site Setup
at the Add-on Configuration
click on LESS Stylesheets Tool section

Then you need check the Enable client-side compiling stylesheets and Enable CSS compression at the LESS Stylesheets Tool control panel:

Enabled the LESS configuration control panel

Also you can access to portal_less tool from the ZMI:

The portal_less tool of ZMI.

Client side compiling¶

Client-side compiling is intended to use while in (theme) development mode.

collective.lesscss will use the standard method for compiling client-side by using the less.js file (v1.3, at the time of this writing) and exposing the LESS resources after the portal_css ones:

<link rel="stylesheet/less" type="text/css" href="styles.less">
<!-- Here goes the rest of portal_javascript resources -->
<script src="less.js" type="text/javascript"></script>

Server side compiling¶

Server-side compiled LESS resources are recommended in production mode. By unsetting this option, the site will server-side compile them into CSS resources and enable a volatile cache on them.

<plone:static
  directory="resources/less"
  type="bootstrap"
  name="less"
  />

And furthermore, if you aren’t using plone.app.theming for develop your theme you should declare the type you are using for your resources by creating this class somewhere in your theme (e.g. traversal.py file):

from plone.resource.traversal import ResourceTraverser

class BootstrapTraverser(ResourceTraverser):
"""The theme traverser.

Allows traveral to /++bootstrap++<name> using ``plone.resource`` to fetch
things stored either on the filesystem or in the ZODB.
"""
name = 'bootstrap'

and later on, declare the adapter via configure.zcml file:

<adapter
  name="bootstrap"
  for="* zope.publisher.interfaces.IRequest"
  provides="zope.traversing.interfaces.ITraversable"
  factory=".traversal.BootstrapTraverser"
/>

So, you should now be able to access to the resources inside the resources directory by accessing:

http://localhost/Plone/++bootstrap++less/

Theme Example¶

You can check out a Twitter Bootstrap integration using the example.bootstrap package for a full example on how to integrate LESS resources in your theme package.