Edgewall Software

Version 4 (modified by Armin Ronacher, 17 years ago) ( diff )

wohoo. that could be *the* solution

Theme Plugins

This proposal describes a way trac could get a working theme support. The main idea is that every project which uses trac should have it's own theme. Or at least each major trac installation.

The current way is overriding htdocs_location in the trac config to bypass the shipped css and js files and inject new ones. Using the site.html file (talking of trac 0.11) you can then override the way the template is rendered. Because of the great Genshi API with XPATH support nearly everything is overrideable. But trac upgrades are a pain in the ass and distributing themes does not work.

Generic CSS Classes

One of the first things which should be done is cleaning up the shipped css files. They should use more generic classes and documented classes. Each plugin developer should be able to use them too in his plugins.

Also the trac core would only ship layout css files without color definitions. The default theme would then add the color definitions for the elements (links, browser etc). Currently the only way to change the trac colors is copying the default css files and replace all the color hex values with own ones.

To create a list of generic classes an analysis of the current css files and genshi templates would be required.

Theme Provider

class MyTheme(Component):
    implements(IThemeProvider, ITemplateProvider)

    # IThemeProvider
    def get_theme_htdocs_id(self):
        return 'mytheme'

    def get_theme_site_template(self):
        return 'mytheme/site.html'

    # ITemplateProvider methods
    def get_templates_dirs(self):
        from pkg_resources import resource_filename
        return [resource_filename(__name__, 'templates')]

    def get_htdocs_dirs(self):
        from pkg_resources import resource_filename
        return [('mytheme', resource_filename(__name__, 'htdocs'))]

There will also be a UserTheme component class which uses the site.html from the trac instance folder and the template/htdocs folder in the instance. It's one of the both default themes:

  • trac - the trac default theme
  • custom - a special theme that forwards the htdocs/template lookups to the instance folders and uses the normal site.html as template.

Themes

A theme looks like the theme defined above. So this could be the mytheme/site.html: 

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:py="http://genshi.edgewall.org/"
      xmlns:xi="http://www.w3.org/2001/XInclude" py:strip="">
  <head py:match="head">
    <!-- load the default header stuff including the layout and plugin css files -->
    ${select('*')}
    <!-- include theme css files -->
    <link rel="stylesheet" href="${theme.get_chrome_url('style/style.css')}" />
    <link rel="stylesheet" href="${theme.get_chrome_url('style/print.css')}" media="print" />
  </head>
  <body py:match="body">
    <!-- normal design used by the project webpage -->
    <div id="header">
      <h1>Project Trac</h1>
    </div>
    <div id="navigation">
      <li><a href="/">Index</a></li>
      <li><a href="/downloads">Downloads</a></li>
      <li><a href="/wiki/">Wiki</a></li>
      <li class="active"><a href="/trac/">Development</a></li>
    </div>

    <!-- embbed the trac -->
    <div id="body">
      <div id="x-trac">
        <div class="sidebar">
          <!-- combine all three navigation bars into one --> 
          <ul class="navigation">
            <!-- include main navigation -->
            ${select('ul[@id="mainnav"]/*')}
            <!-- include meta nav -->
            ${select('ul[@id="metanav"]/*')}
            <!-- include ctx nav -->
            ${select('ul[@id="ctxtnav"]/*')}
          </ul>
            <li>Search
              ${select('div[@id="banner"]/form[@id="search"]')}
            </li>
          </ul>
          <!-- search box -->
          ${select('form[@id="search"]')}
        </div>
        <div class="trac-body">
          ${select('div[@id="main"]/*')}
        </div>
      </div>
    </div>

    <!-- project webpage footer -->
    <div id="footer">
      <a href="http://www.example.org/">Project</a> is open source software licensed
      under the <a href="http://www.gnu.org/copyleft/gpl.html">GPL</a>,
      development page powered by <a href="http://trac.edgewall.org/">Trac</a>.
    </div>
  </body>
</html>

As you can see the idea is that the default layout.html does not include *any* style elements. It just wraps the content elements in divs and uls. (navigation bars, content etc). The default css files have all their rules prefixed with #x-trac in order to avoid clashes with included css files from project webpages. The idea is that you just have to add a div with the idea #x-trac where the trac should appear, select everything there and there you go. Additionally you can of course as shown above, move the navigation bars around thanks to the ass-kicking genshi xpath support.

theme.get_chrome_url() creates an url to the chrome folder of the current theme.

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