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doc: Update the README
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@ -1,191 +1,93 @@
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GStreamer documentation notes
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GStreamer documentation notes
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IMPORTANT
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=========
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||||||
|
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Please make sure you've read and understood everything in this file
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before you try changing documentation.
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Some of the docbook-related bits in this README might be out of date now that
|
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quite a bit of the documentation has moved into the gst-docs repository.
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OVERVIEW
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OVERVIEW
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========
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========
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|
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GStreamer has two sets of documentation that we maintain:
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Our documentation uses hotdoc, you should usually refer to the
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* API references, using gtk-doc (gstreamer, gstreamer-libs)
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[hotdoc documentation](http://hotdoc.github.io/).
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|
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GStreamer has two sets of documentation but both are controlled and aggregated in
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the `gst-docs` module:
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* API references, using hotdoc (gstreamer, gstreamer-libs) - maintained
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in each GStreamer modules repository
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* FAQ / Application Development Manual / Plugin Writer's Guide / Tutorials -
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* FAQ / Application Development Manual / Plugin Writer's Guide / Tutorials -
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these are maintained in markdown format and live in the gst-docs repository.
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these are maintained in markdown format and live in the gst-docs repository.
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DOCBOOK NOTES
|
To build the full documentation you should make sure to have `hotdoc` installed and
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=============
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build [gst-build](https://cgit.freedesktop.org/gstreamer/gst-build/) configuring it with:
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|
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OK, I've grown so tired of having to coax the docs to build every time I
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```
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get round to it that I've decided to note down some of the things that
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meson -Ddoc=enabled build/
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are important to know.
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```
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|
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OVERVIEW
|
And building the documentation:
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||||||
--------
|
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* Our documentation should all be Docbook/XML. No SGML.
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* The source for the documentation is:
|
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- one or more .xml files, with the main one being gstreamer-(whatever).xml
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- image files
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- in .svg
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- in .png (and maybe others)
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* We want to generate docs in HTML, PS and PDF
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* We want to use xml to to generate these
|
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CONVENTIONS
|
```
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-----------
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ninja -C build/ subprojects/gst-docs/GStreamer-doc`, this will result in two documentation sets:
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We stick to some simple conventions for writing docbook documentation.
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```
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* id names:
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- all id's start with chapter-, part-, section-, or misc-
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- verify this is the case by looking at the generated file names in html/
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- sections should also include the chapter name;
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for example in a chapter called chapter-example, a section would be
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called section-example-hello-world
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HOW IMAGES ARE HANDLED
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This will generate two outputs:
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----------------------
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* the format of images used is:
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- PNG for html
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- EPS for ps
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- PDF for pdf
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|
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* images may need to be converted from their source format to the end format
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- the html in `build/subprojects/gst-docs/GStreamer-doc/html`
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- the [devhelp](https://wiki.gnome.org/Apps/Devhelp) in `build/subprojects/gst-docs/GStreamer-doc/devhelp`
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* a file called image.entities is generated that provides two entities:
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ℑ and ℑ
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ℑ is the file extension (png, ps, pdf)
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* all generated images will be put in images/
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HOW THE BUILD WORKS FOR EACH FORMAT
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-----------------------------------
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* HTML:
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- xmlto html gstreamer-whatever.xml should produce the html docs.
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- We do this in the html subdir of the doc builddir.
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- images are copied to (builddir)/html/images
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- PNGS should be set to all of the png's referenced for html, both
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already there and auto-generated
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* PS :
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- images are converted to .ps files in EPS format. Generated images are
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put in images/
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- xmlto ps gstreamer-whatever.xml generates the ps file
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* PDF :
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There are two ways:
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- ps2pdf is the easiest
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- we specify ps, PS as the image type, but using xmlto the build will fail
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because it uses ps2pdf internally and it fails to generate the images
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By hand-generating .pdf images before xmlto we can make the build succeed.
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(This is why image-pdf has file ext pdf but type EPS; this tricks xmlto in
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doing the right thing)
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xmlto pdf gstreamer-whatever.xml generates pdf (but seems to fail on the
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FAQ, so for now we use ps2pdf)
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HOW THE BUILD SYSTEM IS SET UP
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HOW THE BUILD SYSTEM IS SET UP
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------------------------------
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------------------------------
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* make all should build html, ps, and pdf
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Hotdoc build targets are generated for each documentation 'components' (ie. hotdoc
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* html is built in a subdir, with the png/ps images copied there
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subprojects). This includes libraries documentation and one target per GStreamer plugin.
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* ps and pdf are built in the current dir, in one file
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One can build a specific documentation target by explicitely building the target,
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for example to build the GStreamer core library documentation (adapt the paths if you
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are using `gst-build`):
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|
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ninja docs/libgstreamer-doc
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Then the documentation will be avalaible in `docs/libgstreamer-doc/html/`.
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SPELL CHECKING
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SPELL CHECKING
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--------------
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--------------
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* with aspell
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* aspell -b -c --mode=sgml --lang=en <file>.xml
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unfortunately the curses-ui of aspell (0.50.5) has problems with the xml tags
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FILL ME.
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GTK-DOC NOTES
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HOTDOC NOTES
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=============
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=============
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* files under revision control:
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* files under revision control:
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- Makefile.am
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- sitemap.txt: defines the overall structure of the documentation
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- gstreamer-sections.txt
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- gst_plugins_cache.json: Automatically generated information about plugins
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describes which symbols later appear on one api-doc page
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configure which symbols are shown/invisible/private
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- gstreamer.types
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the types file lists all get_type() functions that register the GObject types
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- gstreamer-docs.sgml
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defines the overall structure of the api documentation
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- tmpl/
|
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- only add the file to CVS if you have at least filled the short description
|
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(filename corresponds to the <FILE> tag in the sections file)
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- document as much as possible in the source (*.c files)
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* what to do when adding a new piece of API:
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* what to do when adding a new piece of API:
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- add both an entity and use the entity in gstreamer-docs.sgml
|
- Just let hotdoc generate the documentation and decide where to put it
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- add a new <SECTION> to gstreamer-sections.txt in the correct alphabetical
|
- Make sure to add a `SECTION` documentation section in the file where
|
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position related to the other sections (so that it is easier to locate)
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the documentation should land (hotdoc will use that to create its
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- add all documented symbols to gstreamer-sections.txt in the proper section
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"smart index" and list symbols from other files that should land
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(default),<SUBSECTION Standard>,<SUBSECTION Private>
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on that page in that section.
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- document at least the Short_Description in tmpl/.sgml
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- document symbols where they are defined, so that when one changes the
|
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definition, the chaces are good that docs are updated.
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- document functions, signals in the .c files
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- document functions, signals in the .c files
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- document structs, typedefs, enums in the .h files
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- document structs, typedefs, enums in the .h files
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* checklist:
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- make sure *-sections.txt has a <TITLE> set for each <FILE>
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- add only *one* <TITLE> to each file, when you have multiple classes in one
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source-file, create one <FILE> section for each class
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- the <TITLE> *must* be named like the type of the GType, when it gets
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registered (otherwise gtkdoc introspection fails)
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- for clarity name the <FILE> like the <TITLE>, but all lowercase
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* what to do when trying to improve the docs
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* what to do when trying to improve the docs
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- compare the output of
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- compare the output of
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grep "_get_type" gstreamer-sections.txt | sort
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grep "_get_type" gstreamer-sections.txt | sort
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with the types in XXX.types to detect entries that
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with the types in XXX.types to detect entries that
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are maybe missing
|
are maybe missing
|
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- gtk docs does not warns about empty member docs!, run
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- hotdoc does not warns about empty member docs!, run
|
||||||
find . -name "*.[c,h]" -exec egrep -Hn "^ +\* +@.*: *$" {} \;
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find . -name "*.[c,h]" -exec egrep -Hn "^ +\* +@.*: *$" {} \;
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in the project root to find them
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in the project root to find them
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- gtk docs does not warns about empty Returns: docs!, run
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- hotdoc does not warns about empty Returns: docs!, run
|
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find . -name "*.[c,h]" -exec egrep -Hn "^ +\* +@Returns: *$" {} \;
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find . -name "*.[c,h]" -exec egrep -Hn "^ +\* +@Returns: *$" {} \;
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in the project root to find them
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in the project root to find them
|
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|
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* what happens during a gtk-doc build ?
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* what happens during a hotdoc build ?
|
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- Scan step:
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- Read the GIR and scan the sources files for the docstrings and
|
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- based on a $(MODULE).types file:
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generate the documentation laying out pages the way they are documented.
|
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- gtkdoc-scangobj creates a gtkdoc-scan binary
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- The meson build definition is set in a way that makes it so all plugins
|
||||||
- using CC, LD, CFLAGS, LDFLAGS env var
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in `plugins_doc` are introspected and documented
|
||||||
- using --type-init-func and --module parameters
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- gtkdoc-scan creates
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- $MODULE.signals.new
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- $MODULE.hierarchy.new
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- $MODULE.interfaces.new
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- $MODULE.prerequisites.new
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- $MODULE.args.new
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- generated source and objects get deleted
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- gtkdoc-scangobj merges changes into the original files
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- gtkdoc-scan
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- extracts decls of functions, macros, enums, structs, unions from headers
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|
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- generates
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|
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- $MODULE-decl.txt
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|
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- $MODULE-decl-list.txt
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- $MODULE-decl-list.txt then should get copied to $MODULE-sections.txt
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- scan-build.stamp gets created
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|
|
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- Template generation step:
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STYLE GUIDE FOR HOTDOC
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- gtkdoc-mktmpl --module=$MODULE
|
|
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- reads in tmpl/*.sgml
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|
||||||
- moves them to tmpl/*.sgml.bak
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|
||||||
- recreates tmpl/*.sgml according to $MODULE-sections.txt
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|
||||||
- moves unused stuff to $MODULE-unused.txt
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|
||||||
- tmpl-build.stamp gets generated
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|
||||||
|
|
||||||
* Possible errors and how to fix them
|
|
||||||
- Warning: multiple "IDs" for constraint linkend: gst-tag-register.
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|
||||||
- check if gst_tag_register is listed more than once in -sections.txt
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|
||||||
|
|
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STYLE GUIDE FOR GTK-DOC
|
|
||||||
=======================
|
=======================
|
||||||
- this is in addition to gtk-doc's style-guide.txt
|
- this is in addition to gtk-doc's style-guide.txt
|
||||||
|
|
||||||
- when documenting signals, use "the #Gst..." for the object receiving the
|
|
||||||
signal; no trailing dot, and no "that received the signal"
|
|
||||||
- function/macro descriptions are descriptive, not imperative
|
- function/macro descriptions are descriptive, not imperative
|
||||||
ie, it uses the third person verb
|
ie, it uses the third person verb
|
||||||
- synopsis and description should have most-used/application functions at the
|
- synopsis and description should have most-used/application functions at the
|
||||||
|
@ -201,165 +103,38 @@ STYLE GUIDE FOR GTK-DOC
|
||||||
"Caller owns returned value" for other types (iterators, ..)
|
"Caller owns returned value" for other types (iterators, ..)
|
||||||
- we do this because, in contrast with GLib/GTK, we are more explicit
|
- we do this because, in contrast with GLib/GTK, we are more explicit
|
||||||
about threadsafety and related issues
|
about threadsafety and related issues
|
||||||
- link to signals from the description like this:
|
|
||||||
* The <link linkend="GstBin-element-added">element-added</link> signal
|
|
||||||
|
|
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WEBSITE DOCUMENTATION
|
WEBSITE DOCUMENTATION
|
||||||
=====================
|
=====================
|
||||||
|
|
||||||
Updating the online documentation is pretty simple.
|
Updating the online documentation is done from with the `gst-docs` repository
|
||||||
Make sure that you
|
|
||||||
a) have a working freedesktop.org account
|
|
||||||
b) $HOME/.ssh/config set up so that it has the right User for the Host
|
|
||||||
(for example, I have:
|
|
||||||
Host freedesktop.org
|
|
||||||
User thomasvs
|
|
||||||
c) verify this works by doing ssh freedesktop.org and being logged in without
|
|
||||||
a password prompt
|
|
||||||
d) have verified your changes build documentation locally.
|
|
||||||
|
|
||||||
Then, after updating any of the docs, run "make upload" from that directory.
|
|
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Or, run "make upload" from this (docs) directory.
|
|
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|
|
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DOCUMENTING ELEMENTS
|
DOCUMENTING ELEMENTS
|
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====================
|
====================
|
||||||
As of september 2005 we have some system to document plugins and elements
|
A hotdoc plugin is provided by GStreamer to document GStreamer plugins.
|
||||||
in the various plugin packages.
|
|
||||||
|
|
||||||
- in a submodule, docs go in docs/plugins
|
|
||||||
- template can be copied from gst-plugins-base
|
|
||||||
- to add plugins documentation:
|
|
||||||
- create docs/plugins
|
|
||||||
- create Makefile.am and friends, add to configure.ac
|
|
||||||
- create docs/version.entities.in, add to configure.ac
|
|
||||||
- in docs/plugins:
|
|
||||||
- create $(module)-plugins.types with #include <gst/gst.h>
|
|
||||||
- run make
|
|
||||||
- edit the -docs.sgml
|
|
||||||
- add to cvs:
|
|
||||||
cvs add *-plugins-docs.sgml *-plugins.args *-plugins.hierarchy *-plugins.interfaces *-plugins.prerequisites *-plugins.signals *-plugins.types inspect-build.stamp inspect.stamp scanobj-build.stamp
|
|
||||||
cvs add inspect
|
|
||||||
cvs add inspect/*.xml
|
|
||||||
- Additional types can be added to the documentation by placing them in
|
|
||||||
the .types file like this:
|
|
||||||
type:GstPlayBaseBin
|
|
||||||
This is useful for documenting plugin-private types that implement
|
|
||||||
signals or properties. The GType is looked up by name after all the
|
|
||||||
element classes have been printed - so this is only useful for types
|
|
||||||
that are created as a consequence of loading plugins and registering
|
|
||||||
the element(s).
|
|
||||||
|
|
||||||
- to add a plugin to be documented:
|
- to add a plugin to be documented:
|
||||||
- make sure inspect/ has generated a inspect/plugin-xxx.xml file for it.
|
- make sure the plugin is added to the `plugins_doc` variable in meson
|
||||||
- if it has not, make sure you have pygst installed and run 'make update'.
|
|
||||||
and add it to CVS.
|
|
||||||
- add an xi:include in -docs.sgml in the Plugins chapter for that plugin
|
|
||||||
|
|
||||||
- to add an element to be documented:
|
- to add an element to be documented:
|
||||||
- add an xi:include in the Elements chapter for the element
|
|
||||||
in the main -docs.sgml
|
|
||||||
- add a section for it in -sections.txt with
|
|
||||||
<SECTION>
|
|
||||||
<FILE>element-(element)</FILE>
|
|
||||||
<TITLE>(element)</TITLE>
|
|
||||||
GstXxx
|
|
||||||
<SUBSECTION Standard>
|
|
||||||
GstXxxClass
|
|
||||||
GST_XXX
|
|
||||||
GST_XXX_CLASS
|
|
||||||
GST_IS_XXX
|
|
||||||
GST_IS_XXX_CLASS
|
|
||||||
GST_TYPE_XXX
|
|
||||||
gst_xxx_get_type
|
|
||||||
</SECTION>
|
|
||||||
- add a gtk-doc section to the source code like:
|
- add a gtk-doc section to the source code like:
|
||||||
/**
|
/**
|
||||||
* SECTION:element-multifdsink
|
* SECTION:element-multifdsink
|
||||||
|
|
||||||
and fill it with documentation about the element, preferably inside
|
and fill it with documentation about the element
|
||||||
a <refsect2> docbook container.
|
|
||||||
- add an example:
|
- add an example:
|
||||||
- either a few pipelines, inside <programlisting>
|
- either a few pipelines, inside a codeblock
|
||||||
- or a piece of code:
|
- or a piece of code inside a codeblock or in `tests/examples/(pluginname)`
|
||||||
- create an example program (element)-example.c in the plugin dir
|
- to build the doc for a plugin, do:
|
||||||
- add the full path (starting with $(top_srcdir)) for this example
|
`ninja docs/(pluginname)-doc`
|
||||||
to the EXAMPLE_CFILES variable in Makefile.am
|
|
||||||
- add an xinclude of a file named "element-(element)-example.xml"
|
|
||||||
to the docbook documentation piece in the element source code
|
|
||||||
- add the header to EXTRA_HFILES in Makefile.am to be able to document
|
|
||||||
signals and args; in that case, the object struct needs to be in
|
|
||||||
-sections.txt outside of the Standard Subsection (which is annoying,
|
|
||||||
but ...)
|
|
||||||
(FIXME: are we sure we can both do the xinclude from the tmpl/ sgml,
|
|
||||||
as well as an override from the source itself ? maybe we should just
|
|
||||||
make sure the xinclude is in the source itself instead ?)
|
|
||||||
- if the plugin has no public header, don't add the c-file, add entries to the
|
|
||||||
-overrides.txt file (see playbin docs in plugins-base).
|
|
||||||
- to rebuild the docs, do:
|
|
||||||
make clean
|
|
||||||
make update
|
|
||||||
make
|
|
||||||
- examples will only show up using gtk-doc 1.4 or later - it relies on
|
|
||||||
merging stuff from .sgml with inline docs. We might want to change
|
|
||||||
this to only get stuff from the source.
|
|
||||||
- you need to commit resulting files to git:
|
|
||||||
- changes to *.signals and *.args
|
|
||||||
- new files for your plugin created in inspect/
|
|
||||||
- if you get this warning:
|
|
||||||
" Documentation in template xxx for ./tmpl/element-yyy:Short_Description
|
|
||||||
being overridden by inline comments"
|
|
||||||
per-default the description from the GST_ELEMENT_DETAILS is put to the
|
|
||||||
Short_Description. This warning mean you have a different one in the section
|
|
||||||
docs as "@short_description:".
|
|
||||||
|
|
||||||
- the plugin-doc-list on the gstreamer homepage is updated along with other
|
|
||||||
web site updates.
|
|
||||||
|
|
||||||
- maintainer tricks:
|
|
||||||
- in gst-plugins-foo/docs/plugins/, run
|
|
||||||
make check-inspected-versions
|
|
||||||
to show plugins whose inspect information is not up-to-date (which is
|
|
||||||
usually either because they have been moved to a different module or
|
|
||||||
because they are not built on the maintainer's machine for some reason).
|
|
||||||
Whether it really makes sense to update the version number is debatable
|
|
||||||
(after all, the inspected information may be outdated and things may have
|
|
||||||
changed, in which case it would be bad to change the version number)
|
|
||||||
- find files that have docs
|
|
||||||
for file in `find . -name "*.c" -exec grep -l " * SECTION:element-" {} \; | sort`; do if [ -e ${file/.c/.h} ]; then echo ${file/.c/.h}; else echo "no header for $file"; fi; done
|
|
||||||
for file in `find . -name "*.cc" -exec grep -l " * SECTION:element-" {} \; | sort`; do if [ -e ${file/.cc/.h} ]; then echo ${file/.cc/.h}; else echo "no header for $file"; fi; done
|
|
||||||
- add those .h files to EXTRA_HFILES in Makefile.am
|
|
||||||
- update gst-plugins-xxx-docs.sgml
|
|
||||||
cd docs/plugins
|
|
||||||
ls -1 xml/plugin-*.xml | sort | sed -e "s/\(.*\)/ \<xi:include href=\"\1\" \/\>/"
|
|
||||||
ls -1 xml/element-*.xml | grep -v -- "-details.xml" | sort | sed -e "s/\(.*\)/ \<xi:include href=\"\1\" \/\>/"
|
|
||||||
- maybe we can generate these lists after "make update" and just xi:include
|
|
||||||
them in gst-plugins-xxx-docs.sgml. They should be committed to the vcs.
|
|
||||||
|
|
||||||
- possible errors:
|
|
||||||
- "multiple constraints for linkend ID":
|
|
||||||
check if each section in -sections.txt actually starts and ends with
|
|
||||||
<SECTION> and </SECTION>
|
|
||||||
- if a plugin does not show up:
|
|
||||||
- check inspect/plugin-xxx.xml and tmpl/elements-
|
|
||||||
|
|
||||||
RANDOM THINGS I'VE LEARNED
|
|
||||||
==========================
|
|
||||||
|
|
||||||
* for clean builddir != srcdir separation, I wanted to use xmlto --searchpath
|
|
||||||
so the source xml could find the built entity file.
|
|
||||||
But xmlto --searchpath is (right now) for TeX input, not xml input.
|
|
||||||
xsltproc has a --path option (that xmlto doesn't use yet), but it
|
|
||||||
resolves single files to $(specified_path)/$(srcdir)/$(file)
|
|
||||||
For now, we need to hack around it by copying xml to the build dir.
|
|
||||||
|
|
||||||
|
|
||||||
DEVHELP INTEGRATION
|
DEVHELP INTEGRATION
|
||||||
-------------------
|
-------------------
|
||||||
Check https://wiki.gnome.org/Apps/Devhelp
|
Check https://wiki.gnome.org/Apps/Devhelp
|
||||||
It's a really nice development app allowing you to look up API stuff
|
It's a really nice development app allowing you to look up API stuff
|
||||||
from various gtk-doc'd libraries. GStreamer is one of these ;)
|
from various hotdoc/gtk-doc'd libraries. GStreamer is one of these ;)
|
||||||
|
|
||||||
gtk-doc generates both html API docs and the matching .devhelp(2) books.
|
hotdoc generates both html API docs and the matching .devhelp(2) books.
|
||||||
|
|
||||||
IMAGES
|
IMAGES
|
||||||
------
|
------
|
||||||
|
|
Loading…
Reference in a new issue