This theme_support version has been updated by Damien Le Berrigaud for Rails 2.0
http://www.webdrivenblog.com/

It was then forked for Rails 2.2 (and later 2.3) support by James Stewart - http://jystewart.net/process/

Some notes on the integration of Rails 2.3 support can be found at:
http://jystewart.net/process/tag/theme_support/

= Theme Support for Rails Applications

This plugin provides support for themes to the rails application environment. 
It supports theme specific images, stylesheets, javascripts, and views. The 
views can be in ERb (rhtml) or liquid formats. Optionally, you can configure 
the theme system to ignore any templates except liquid ones.

== Tests

A test application with a range of cucumber-based tests is available separately at:

http://github.com/jystewart/theme_support_test_app


== Changes from the original version

 * Rake tasks are now namespaced, eg: "rake themes:cache:create" instead of "rake theme_create_cache"
 * Layouts now live within themes/[theme_name]/views/layouts to match up with Rails conventions

== Known Issues

Liquid template handling is not tested in 2.2 or 2.3
The various asset methods (theme_stylesheet_link_tag etc.) don't work in 2.2

== Usage

This plugin automatically makes any patches needed for theme support. You can
use the theme_generator to create the file structure needed, or create it 
yourself.

It expects the following theme folder structure.

  $app_root
    themes/
      [theme_name]
        
        images/
        stylesheets/
        javascripts/
        views/           <- you can override application views
          layouts/         <- layout .rhtml or .liquid templates
        about.markdown
        preview.png

When run in production mode, it will automatically cache the theme files so that
the web-server will deliver them in subsequent requests. 

It bears noting that, like Typo, this will mean your apache/fcgi process will need
write permissions. This could be a possible security vulnerability.

With that in mind, it is best to pre-cache all of the theme files by using the 
included rake tasks:

  $ rake theme_create_cache

The theme file cache generates the following file structure:

  $app_root
    public/
      themes/
        [theme_name]/
          images/
          stylesheets/
          javascripts/

There are other rake tasks available:

 - theme_create_cache
 - theme_remove_cache
 - theme_update_cache

You specify which theme to use in your controller by using the 'theme' helper.
It's used just like the 'layout' helper. In fact, you can use them both 
simultaneously. The following will render actions using the 'default' layout 
in the 'blue_bird' theme (theme/blue_bird/layouts/default.rhtml):

  class ApplicationController < ActionController::Base
    layout 'default'

    theme 'blue_bird'

    ...
  end

You can also defer the theme lookup to a controller method:

  class ApplicationController < ActionController::Base
    layout 'default'

    theme :get_theme

    def get_theme

      # If you let the user choose their own theme, you might
      # add a User#theme field...

      current_user.theme
    end

    ...
  end


Note: By setting the theme in the ApplicationController you can set 
the theme for the whole application.

In your application views, there are theme specific helper tags 
available to you. For ERb templates they are:

 - theme_image_tag
 - theme_image_path
 - theme_javascript_include_tag
 - theme_javascript_path
 - theme_stylesheet_link_tag
 - theme_stylesheet_path

For liquid templates there is a single helper, themeitem,  that will determine 
the path base on the theme file extension. Here's how you'd use it:

  <link rel="StyleSheet" href="{% themeitem %} default.css {% endthemeitem %}" />
  ...
  <img src="{% themeitem %} logo.png {% endthemeitem %}" />

The output from those two calls are:

  <link rel="StyleSheet" href="/themes/[current_theme]/stylesheets/default.css" />
  ...
  <img src="/themes/[current_theme]/images/logo.png" />

New in version 1.4 is ActionMailer support. Note, this is still experimental. However,
if you would like your themes to be able to override your ActionMailer views, you can
send the theme in your deliver_* method call. For example, assuming we have an ActionMailer
class named Mailer, and have implemented theme_support as shown above, here's how you would
allowing themes in emails:


  def send_email
    Mailer.deliver_my_email( 'a variable', :theme=>get_theme )
  end

 
== Contributors

The theme_support pluging includs patches from the following:

* agkr
* D.J. Vogel

Thanks guys!

== Changelog

  1.4.0 - Better support for Rails 1.1+. Updated the liquid themeitem tag.
          Liquid layouts are no longer generated by default.Added a couple 
          of patches. One allows theme sub-directories. For example, you 
          can have:
        
            [theme_dir]
              stylesheets/
                admin/
                  main.css
        
          Added experimental support for themeing ActionMailer classes.
          They work as normal, if you want to all theme's to override the
          .rhtml|.liquid views, send the theme in the deliver_* method. For
          example:
        
            Mailer.deliver_signup( user, :theme=>get_theme() )
        
          In that example, `get_theme` is a method on the controller and at 
          the top we've used:
        
            layout 'default'
            theme :get_theme
        
  1.3.0 - The theme_system component is no longer needed. All of the
          theme support is driven by a single plugin named, oddly enough, 
          'theme_support'. Also improved theme route support. Instead of
          overriding RouteSet#reload, RouteSet#draw is overridden, making
          the theme support entirely transparent -- hopefully ;-) 

  1.2.2 - More Bug-fixes.

  1.2.1 - Bug-fixes and documentation clean up.

  1.2.0 - Updated actionview_ex with the new render_file additions from 
          Typo. Renamed the rake tasks so that they all start with 
          'theme' (theme_create_cache, theme_remove_cache, 
          theme_update_cache). You can update the system files by running:
        
            $ ./script/generate theme _system_

          Full support for Liquid templates, as well as an option to only
          allow Liquid templates in a theme.

  1.1.1 - Added rake tasks for pre-caching the themes, and removing the
          cached themes. 

  1.1.0 - [Breaking] Abstraction of the Typo theme system. The themes are
          now the same as is used in Typo. The theme engine itself is a
          combination of plugins and a component. No more symlinks, thank
          goodness.

  1.0.2 - The current_theme is now retrieved from the controller. Where
          symlinks are created on *nix systems, shortcuts are created 
          on Windows if Win32Utils is installed.

  1.0.1 - Added 'themes' directory, theme definition file, and symlinks 
          to the appropriate directories on supported platforms.

  1.0.0 - Initial release


---
Copyright (c) 2005 Matt McCray, based on code from Typo by Tobias Luetke 
released under the MIT license