HTML theme development ====================== .. versionadded:: 0.6 .. note:: This document provides information about creating your own theme. If you simply wish to use a pre-existing HTML themes, refer to :doc:`/usage/theming`. Sphinx supports changing the appearance of its HTML output via *themes*. A theme is a collection of HTML templates, stylesheet(s) and other static files. Additionally, it has a configuration file which specifies from which theme to inherit, which highlighting style to use, and what options exist for customizing the theme's look and feel. Themes are meant to be project-unaware, so they can be used for different projects without change. .. note:: See :ref:`dev-extensions` for more information that may be helpful in developing themes. Creating themes --------------- Themes take the form of either a directory or a zipfile (whose name is the theme name), containing the following: * Either a :file:`theme.toml` file (preferred) or a :file:`theme.conf` file. * HTML templates, if needed. * A ``static/`` directory containing any static files that will be copied to the output static directory on build. These can be images, styles, script files. Theme configuration (``theme.toml``) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The :file:`theme.toml` file is a TOML_ document, containing two tables: ``[theme]`` and ``[options]``. The ``[theme]`` table defines the theme's settings: * **inherit** (string): The name of the base theme from which to inherit settings, options, templates, and static files. All static files from theme 'ancestors' will be used. The theme will use all options defined in inherited themes. Finally, inherited themes will be used to locate missing templates (for example, if ``"basic"`` is used as the base theme, most templates will already be defined). If set to ``"none"``, the theme will not inherit from any other theme. Inheritance is recursive, forming a chain of inherited themes (e.g. ``default`` -> ``classic`` -> ``basic`` -> ``none``). * **stylesheets** (list of strings): A list of CSS filenames which will be included in generated HTML header. Setting the :confval:`html_style` config value will override this setting. Other mechanisms for including multiple stylesheets include ``@import`` in CSS or using a custom HTML template with appropriate ```` tags. * **sidebars** (list of strings): A list of sidebar templates. This can be overridden by the user via the :confval:`html_sidebars` config value. * **pygments_style** (table): A TOML table defining the names of Pygments styles to use for highlighting syntax. The table has two recognised keys: ``default`` and ``dark``. The style defined in the ``dark`` key will be used when the CSS media query ``(prefers-color-scheme: dark)`` evaluates to true. ``[theme.pygments_style.default]`` can be overridden by the user via the :confval:`pygments_style` config value. The ``[options]`` table defines the options for the theme. It is structured such that each key-value pair corresponds to a variable name and the corresponding default value. These options can be overridden by the user in :confval:`html_theme_options` and are accessible from all templates as ``theme_``. .. versionadded:: 7.3 ``theme.toml`` support. .. _TOML: https://toml.io/en/ Exemplar :file:`theme.toml` file: .. code-block:: toml [theme] inherit = "basic" stylesheets = [ "main-CSS-stylesheet.css", ] sidebars = [ "localtoc.html", "relations.html", "sourcelink.html", "searchbox.html", ] # Style names from https://pygments.org/styles/ pygments_style = { default = "style_name", dark = "dark_style" } [options] variable = "default value" Theme configuration (``theme.conf``) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The :file:`theme.conf` file is in INI format [1]_ (readable by the standard Python :mod:`configparser` module) and has the following structure: .. sourcecode:: ini [theme] inherit = base theme stylesheet = main CSS name pygments_style = stylename sidebars = localtoc.html, relations.html, sourcelink.html, searchbox.html [options] variable = default value * The **inherit** setting gives the name of a "base theme", or ``none``. The base theme will be used to locate missing templates (most themes will not have to supply most templates if they use ``basic`` as the base theme), its options will be inherited, and all of its static files will be used as well. If you want to also inherit the stylesheet, include it via CSS' ``@import`` in your own. * The **stylesheet** setting gives a list of CSS filenames separated commas which will be referenced in the HTML header. You can also use CSS' ``@import`` technique to include one from the other, or use a custom HTML template that adds ```` tags as necessary. Setting the :confval:`html_style` config value will override this setting. * The **pygments_style** setting gives the name of a Pygments style to use for highlighting. This can be overridden by the user in the :confval:`pygments_style` config value. * The **pygments_dark_style** setting gives the name of a Pygments style to use for highlighting when the CSS media query ``(prefers-color-scheme: dark)`` evaluates to true. It is injected into the page using :meth:`~sphinx.application.Sphinx.add_css_file()`. * The **sidebars** setting gives the comma separated list of sidebar templates for constructing sidebars. This can be overridden by the user in the :confval:`html_sidebars` config value. * The **options** section contains pairs of variable names and default values. These options can be overridden by the user in :confval:`html_theme_options` and are accessible from all templates as ``theme_``. .. versionadded:: 1.7 sidebar settings .. versionchanged:: 5.1 The stylesheet setting accepts multiple CSS filenames Convert ``theme.conf`` to ``theme.toml`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INI-style theme configuration files (``theme.conf``) can be converted to TOML via a helper programme distributed with Sphinx. This is intended for one-time use, and may be removed without notice in a future version of Sphinx. .. code-block:: console $ python -m sphinx.theming conf_to_toml [THEME DIRECTORY PATH] The required argument is a path to a directory containing a ``theme.conf`` file. The programme will write a ``theme.toml`` file in the same directory, and will not modify the original ``theme.conf`` file. .. versionadded:: 7.3 .. _distribute-your-theme: Distribute your theme as a Python package ----------------------------------------- As a way to distribute your theme, you can use a Python package. This makes it easier for users to set up your theme. To distribute your theme as a Python package, please define an entry point called ``sphinx.html_themes`` in your ``pyproject.toml`` file, and write a ``setup()`` function to register your theme using the :meth:`~sphinx.application.Sphinx.add_html_theme` API: .. code-block:: toml # pyproject.toml [project.entry-points."sphinx.html_themes"] name_of_theme = "your_theme_package" .. code-block:: python # your_theme_package.py from os import path def setup(app): app.add_html_theme('name_of_theme', path.abspath(path.dirname(__file__))) If your theme package contains two or more themes, please call ``add_html_theme()`` twice or more. .. versionadded:: 1.2 'sphinx_themes' entry_points feature. .. deprecated:: 1.6 ``sphinx_themes`` entry_points has been deprecated. .. versionadded:: 1.6 ``sphinx.html_themes`` entry_points feature. Templating ---------- The :doc:`guide to templating ` is helpful if you want to write your own templates. What is important to keep in mind is the order in which Sphinx searches for templates: * First, in the user's ``templates_path`` directories. * Then, in the selected theme. * Then, in its base theme, its base's base theme, etc. When extending a template in the base theme with the same name, use the theme name as an explicit directory: ``{% extends "basic/layout.html" %}``. From a user ``templates_path`` template, you can still use the "exclamation mark" syntax as :ref:`described in the templating document `. .. _theming-static-templates: Static templates ~~~~~~~~~~~~~~~~ Since theme options are meant for the user to configure a theme more easily, without having to write a custom stylesheet, it is necessary to be able to template static files as well as HTML files. Therefore, Sphinx supports so-called "static templates", like this: If the name of a file in the ``static/`` directory of a theme (or in the user's static path, for that matter) ends with ``_t``, it will be processed by the template engine. The ``_t`` will be left from the final file name. For example, the *classic* theme has a file ``static/classic.css_t`` which uses templating to put the color options into the stylesheet. When a documentation project is built with the classic theme, the output directory will contain a ``_static/classic.css`` file where all template tags have been processed. Use custom page metadata in HTML templates ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Any key / value pairs in :doc:`field lists ` that are placed *before* the page's title will be available to the Jinja template when building the page within the :data:`meta` attribute. For example, if a page had the following text before its first title: .. code-block:: rst :mykey: My value My first title -------------- Then it could be accessed within a Jinja template like so: .. code-block:: jinja {%- if meta is mapping %} {{ meta.get("mykey") }} {%- endif %} Note the check that ``meta`` is a dictionary ("mapping" in Jinja terminology) to ensure that using it in this way is valid. Defining custom template functions ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sometimes it is useful to define your own function in Python that you wish to then use in a template. For example, if you'd like to insert a template value with logic that depends on the user's configuration in the project, or if you'd like to include non-trivial checks and provide friendly error messages for incorrect configuration in the template. To define your own template function, you'll need to define two functions inside your module: * A **page context event handler** (or **registration**) function. This is connected to the :class:`.Sphinx` application via an event callback. * A **template function** that you will use in your Jinja template. First, define the registration function, which accepts the arguments for :event:`html-page-context`. Within the registration function, define the template function that you'd like to use within Jinja. The template function should return a string or Python objects (lists, dictionaries) with strings inside that Jinja uses in the templating process .. note:: The template function will have access to all of the variables that are passed to the registration function. At the end of the registration function, add the template function to the Sphinx application's context with ``context['template_func'] = template_func``. Finally, in your extension's ``setup()`` function, add your registration function as a callback for :event:`html-page-context`. .. code-block:: python # The registration function def setup_my_func(app, pagename, templatename, context, doctree): # The template function def my_func(mystring): return "Your string is %s" % mystring # Add it to the page's context context['my_func'] = my_func # Your extension's setup function def setup(app): app.connect("html-page-context", setup_my_func) Now, you will have access to this function in jinja like so: .. code-block:: jinja
{{ my_func("some string") }}
Add your own static files to the build assets ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ By default, Sphinx copies static files on the ``static/`` directory of the template directory. However, if your package needs to place static files outside of the ``static/`` directory for some reasons, you need to copy them to the ``_static/`` directory of HTML outputs manually at the build via an event hook. Here is an example of code to accomplish this: .. code-block:: python from os import path from sphinx.util.fileutil import copy_asset_file def copy_custom_files(app, exc): if app.builder.format == 'html' and not exc: staticdir = path.join(app.builder.outdir, '_static') copy_asset_file('path/to/myextension/_static/myjsfile.js', staticdir) def setup(app): app.connect('build-finished', copy_custom_files) Inject JavaScript based on user configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If your extension makes use of JavaScript, it can be useful to allow users to control its behavior using their Sphinx configuration. However, this can be difficult to do if your JavaScript comes in the form of a static library (which will not be built with Jinja). There are two ways to inject variables into the JavaScript space based on user configuration. First, you may append ``_t`` to the end of any static files included with your extension. This will cause Sphinx to process these files with the templating engine, allowing you to embed variables and control behavior. For example, the following JavaScript structure: .. code-block:: none mymodule/ ├── _static │   └── myjsfile.js_t └── mymodule.py Will result in the following static file placed in your HTML's build output: .. code-block:: none _build/ └── html └── _static    └── myjsfile.js See :ref:`theming-static-templates` for more information. Second, you may use the :meth:`.Sphinx.add_js_file` method without pointing it to a file. Normally, this method is used to insert a new JavaScript file into your site. However, if you do *not* pass a file path, but instead pass a string to the "body" argument, then this text will be inserted as JavaScript into your site's head. This allows you to insert variables into your project's JavaScript from Python. For example, the following code will read in a user-configured value and then insert this value as a JavaScript variable, which your extension's JavaScript code may use: .. code-block:: python # This function reads in a variable and inserts it into JavaScript def add_js_variable(app): # This is a configuration that you've specified for users in `conf.py` js_variable = app.config['my_javascript_variable'] js_text = "var my_variable = '%s';" % js_variable app.add_js_file(None, body=js_text) # We connect this function to the step after the builder is initialized def setup(app): # Tell Sphinx about this configuration variable app.add_config_value('my_javascript_variable', 0, 'html') # Run the function after the builder is initialized app.connect('builder-inited', add_js_variable) As a result, in your theme you can use code that depends on the presence of this variable. Users can control the variable's value by defining it in their :file:`conf.py` file. .. [1] It is not an executable Python file, as opposed to :file:`conf.py`, because that would pose an unnecessary security risk if themes are shared.