Add a new Sphinx extension that knows about the translations of kernel
documentation and can insert links to the translations at the top of
the document.

It basically works like this:

1. Register a new node type, LanguagesNode.

2. Register a new transform, TranslationsTransform, that inserts a new
   LanguageNode at the top of every document. The LanguageNode contains
   "pending references" to translations of the document. The key here
   is that these are pending (i.e. unresolved) references that may or
   may not actually exist.

3. Register a 'doctree-resolved' event that iterates over all the
   LanguageNode nodes. Any unresolved references are filtered out; the
   list of resolved references is passed to the 'translations.html'
   template and rendered as an HTML node (if HTML output is selected).

Testing: make htmldocs, make latexdocs with Sphinx v4.3.2 and Firefox.

v2:
- changed bar into a drop-down menu
- fixed language labels
- fixed hysteresis reported by Akira Yokosawa

Cc: Federico Vaga <federico.vaga@vaga.pv.it>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231215123701.2712807-1-vegard.nossum@oracle.com

The docs currently have <h3> and <h4> set to the same font size which
makes headings hard to distinguish. <h1> to <h3> already have entries in
sphinx-static/custom.css to shrink their size a bit from the alabaster
theme.

Add <h4> to custom.css and set it to be smaller than <h3>.

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231212213137.98453-1-donald.hunter@gmail.com

We already have the logo, let's use it.

Testing: make htmldocs

Cc: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231029074207.297663-1-vegard.nossum@oracle.com

The "toc-title" class was introduced in commit ef88f10e
("[media] doc-rst: backward compatibility with older Sphinx versions")
as a workaround for Sphinx versions older than 1.4.x. However, these
old versions have been deprecated since commit 31abfdda
("docs: Deprecate use of Sphinx < 2.4.x").

Having now changed all the toc-title users to use the :caption:
attribute, we can also remove the custom style.

Note that the toc-title class is separate from the "kernel-toc"
logic that was introduced in commit c404f5d4 ("docs: Add more
information to the HTML sidebar").

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231027081830.195056-12-vegard.nossum@oracle.com

The rtd theme already styles toctree captions as headings, but the
alabaster theme doesn't. Add this in.

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231027081830.195056-2-vegard.nossum@oracle.com

Add a new sidebar template that creates a more RTD-like "fisheye" view of
the current place in the document hierarchy.  It is far from ideal, but
some readers may find it better for navigating through the documentation as
a whole.

Add some CSS trickery as well to make the table of contents less intrusive
when viewing the pages on a small screen.

Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The alabaster theme likes to provide explicit sizes for fonts, which
overrides the users's own browser settings and is guaranteed to displease
folks.  Set the font size to "inherit" so that the users browser settings
control the font size they get.  We can use the font_size configuration
option for the main body font (changing the size I'd already put there),
but the sidebar size can only be set via custom CSS.

Reported-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Make a few changes to cause functions documented by kerneldoc to stand out
better in the rendered documentation.  Specifically, change kernel-doc to
put the description section into a ".. container::" section, then add a bit
of CSS to indent that section relative to the function prototype (or struct
or enum definition).  Tweak a few other CSS parameters while in the
neighborhood to improve the formatting.

Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This is just the beginning: tighten up the layout a bit to improve the
information density in the browser.  Also reconfigure the page width in
terms of character units (em) rather than pixels, making it more
display-independent.  To that end, add a custom.css file to
tweak Alabaster CSS settings.

Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This is actually an overlay on the top of the RTD theme, which
requires to include first the RTD theme.

It should be noticed that, when the dark theme is used, the
DOCS_CSS files won't be the last CSS themes. So, it won't
override the dark.css style by default. So, it is needed
to force the them override with "!important".

This small script, for instance, produces a nice output with
the RTD dark theme:

	DOCS_THEME=sphinx_rtd_dark_mode
	cat << EOF > dark_override.css
	  html body {
	    font-family: arial,helvetica,sans-serif;
	  }
	  html[data-theme='dark'] body {
	    color: white !important;
	  }
	  html[data-theme='dark'] .sig-name {
	    color: green !important;
	  }
	  html[data-theme='dark'] .wy-menu-vertical a {
	    color: #ffcc00 !important;
	  }
	  html[data-theme="dark"] h1, html[data-theme="dark"] h2, html[data-theme="dark"] h3 {
	    color: #ffcc00 !important;
	  }
	  html[data-theme="dark"] h4, html[data-theme="dark"] h5, html[data-theme="dark"] h6 {
	    color: #ffcc00 !important;
	  }
	  html[data-theme="dark"] h7, html[data-theme="dark"] h8, html[data-theme="dark"] h9 {
	    color: #ffcc00 !important;
	  }
	  html[data-theme="dark"] .wy-nav-content a, html[data-theme="dark"] .wy-nav-content a:visited {
	    color: #ffcc00 !important;
	  }
	EOF

	make DOCS_CSS=dark_override.css DOCS_THEME=sphinx_rtd_dark_mode htmldocs

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/90d316e055ef7f4c9021b9eada8f8d3b2e750a66.1638870323.git.mchehab+huawei@kernel.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Right now any ":Field Name: Field Contents" lines end up with significant
padding due to CSS from the "table" CSS which rightly needs padding to
make tables readable. However, field lists don't need this as they tend
to be stacked together. The future heavy use of fields in the parsed
MAINTAINERS file needs this cleaned up, and existing users look better
too. Note the needless white space (and misalignment of name/contents)
between "Date" and "Author":

https://www.kernel.org/doc/html/latest/accounting/psi.html



This patch fixes this by lowering the padding with a more specific CSS.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

My eyesight is not in good shape, which means that I have difficulty
reading the online Linux documentation.  Specifically, body text is
oddly small compared to list items and the contrast of various text
elements is too low for me to be able to see easily.

Therefore, alter the HTML theme overrides to make the text larger and
increase the contrast for better visibility, and trust the typeface
choices of the reader's browser.

For the PDF output, increase the text size, use a sans-serif typeface
for sans-serif text, and use a serif typeface for "roman" serif text.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

In a code-block with line numbers (option :lineno:) there is a
misalignment of the rendered source code lines on the right side and the
line numbers on the left side.

  https://github.com/rtfd/sphinx_rtd_theme/issues/419



Since this issue is reported to the RTD theme project, it might be fixed
in the future (take this as a interim solution).

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

List items with two ore more blocks are not well rendered. E.g. the gap
between last block (l1-b2) of the first list item and the following list
item (L2) is to small::

    * L1 xxxxxxxxxx
      xxxxxxxxxxxxx

      l1-b2 xxxxxxx
      xxxxxxxxxxxxx
    * L2 xxxxxxxxxx
      xxxxxxxxxxxxx

So that it can be read more liquidly, a distance was added to the last
block (l1-b2)::

    * L1 xxxxxxxxxx
      xxxxxxxxxxxxx

      l1-b2 xxxxxxx
      xxxxxxxxxxxxx

    * L2 xxxxxxxxxx
      xxxxxxxxxxxxx

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

As we're about to use those two markups, add them to the
theme style overrride.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Remove the distracting (left/right) padding of inline literals. (HTML
<code>). Requested and discussed in [1].

[1] http://www.spinics.net/lists/linux-media/msg103991.html



Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Sphinx is really evil when an older version finds an extra
attribute for the :toctree: tag: it simply ignores everything
and produce documents without any chapter inside!

As we're now using tags available only on Sphinx 1.4.x, we
need to use some creative ways to add a title before the
table of contents. Do that by using a css class.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The layout of (table) captions in the RTD theme is a bit ugly and the
bordered, red colored of inline literals is a bit to gaudy. The
requirements has been discussed in the ML [1].

captions:

  - captions should have 100% (not 85%) font size
  - hide the permalink symbol as long as link is not hovered

inline literal:

  - drop the borderbox and red color

[1] http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/101099



Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>

The default table layout of the RTD theme does not fit for vast tables,
like the ones we have in the linux_tv project. This has been discussed
on the ML [1].

The RTD theme is a two column layout, with a navigation column on the
left and a content column on the right:

content column

 RTD theme's default is 800px as max width for the content, but we have
 tables with tons of columns, which need the full width of the
 view-port (BTW: *full width* is what DocBook's HTML is).

table

   - sequences of whitespace should collapse into a single whitespace.
   - make the overflow auto (scrollbar if needed)
   - align caption "left" ("center" is unsuitable on vast tables)

[1] http://article.gmane.org/gmane.linux.kernel/2216509



Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>

Implements the minimal boilerplate for Sphinx HTML theme customization.

Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>