While doxygen can handle markdown pages, support for it is very limited:
markdown pages can only be included as a whole page, they get an automatic
title (custom titles are possible but aren't standard markdown) and it's not
possible to use \subpage without messing with the markdown again. Any markdown
page will thus end up as separate item in the doxygen output, not really
suitable for generating a good page hiearchy.
Let's switch the tutorial to use doxygen directly instead of markdown, short
of using code/endcode instead of markdown's ``` there isn't that much
difference anyway but it allows us to structure things nicer in the online
docs.
This requires a helper script: doxygen doesn't differ between static methods
and static inline methods. EXTRACT_STATIC defines whether it parses *any*
static method but we're currently using all C files as input files as well. We
cannot convince doxygen to just parse static inline functions in header files
so for SPA we hack around this: meson passes the spa headers to a shell script
with simply copies those changed to `/* static */ inline void (foo)` and doxygen
then runs on those header files.
The result: we get all spa functions added to your doxygen output at the cost
of a few sed calls.
Theme from doxygen-awesome-css with custom modifications based on the
pipewire.org website to use the same type of blue, grey, etc.
doxygen-awesome-css is MIT licensed, see
https://github.com/jothepro/doxygen-awesome-css
Note that the order of the includes matters - that's how doxygen will sort
them. There is no specific structure other than the include order - one reason
why the headers are being changed. Without polluting the markdown files with
doxygen commands we cannot use \subpage, so all files convert to a regular
\page and are listed as flat hierarchy in the sidebar (and in Related Pages).
Changing the headers at least provides some visual grouping with comon
prefixes.
Keep all files as strings in an array so we can add them to the custom command
input list - this way meson will correctly rebuild documentation on changes.
