Thank you for considering contributing to GdkPixbuf!
These guidelines are meant for new contributors, regardless of their level of proficiency; following them allows the core developers of GdkPixbuf to more effectively evaluate your contribution, and provide prompt feedback to you. Additionally, by following these guidelines you clearly communicate that you respect the time and effort that the people developing GdkPixbuf put into managing the project.
GdkPixbuf is a free software utility library, and it would not exist without contributions from the free and open source software community. There are many things that we value:
- bug reporting and fixing
- documentation and examples
- tests
- testing and support for other platforms
- new features
Please, do not use the issue tracker for support questions. If you have questions on how to use GdkPixbuf effectively, you can use:
- the
#gtk+
IRC channel on irc.gnome.org - the gtk mailing list, for general questions on GdkPixbuf
- the gtk-devel mailing list, for questions on developing GdkPixbuf itself
The issue tracker is meant to be used for actionable issues only.
GdkPixbuf is a library with a long history, and it has been incrementally modified over years, so it may retain some older coding practices alongside newer ones.
As it deals with loading image data into user processes, it's also important to note that GdkPixbuf must always deal with potential security issues.
You should not open a new issue for security related questions.
When in doubt, send an email to the security mailing list.
If you’re reporting a bug make sure to list:
- which version of GdkPixbuf (and its dependencies) are you using?
- which operating system are you using?
- the necessary steps to reproduce the issue
- the expected outcome
- a description of the behavior
- a small, self-contained example exhibiting the behavior
If the issue includes a crash, you should also include:
- the eventual warnings printed on the terminal
- a backtrace, obtained with tools such as GDB or LLDB
If the issue includes a memory leak, you should also include:
- a log of definite leaks from a tool such as valgrind’s memcheck
For small issues, such as:
- spelling/grammar fixes in the documentation,
- typo correction,
- comment clean ups,
- changes to metadata files (CI,
.gitignore
), - build system changes, or
- source tree clean ups and reorganizations;
or for self-contained bug fixes where you have implemented and tested a solution already, you should directly open a merge request instead of filing a new issue.
If you wish to contribute to GdkPixbuf you will need to install the appropriate development tools for your operating system, including:
- Python 3.x
- Meson
- Ninja
- Gettext
- a C99 compatible compiler
You can start by cloning the Git repository:
$ git clone https://gitlab.gnome.org/GNOME/gdk-pixbuf.git
$ cd gdk-pixbuf
Then you should build GdkPixbuf locally:
$ meson _build .
$ cd _build
$ ninja
Once you built GdkPixbuf, you should create a new branch in order to work on your bug fix, or your feature, undisturbed:
$ git checkout -b my-amazing-feature
[ work work work ... ]
You should run the test suite locally, to verify you are not introducing a regression; if you are fixing a bug, you should also add a test case to verify that the fix works and to avoid future regressions; if you are introducing a new feature, you should write a comprehensive test suite:
$ cd _build
$ meson test
When introducing a new feature or new API, you should document it using the
gtk-doc format. You
can build the GdkPixbuf API reference locally by enabling the docs
configuration option and building the gdk-pixbuf-doc
target:
$ cd _build
$ meson configure -Ddocs=true
$ ninja
$ ninja gdk-pixbuf-doc
The expected format for git commit messages is as follows:
Short explanation of the commit
Longer explanation explaining exactly what’s changed, whether any
external or private interfaces changed, what bugs were fixed (with bug
tracker reference if applicable) and so forth. Be concise but not too
brief.
Closes #1234
-
Always add a brief description of the commit to the first line of the commit and terminate by two newlines (it will work without the second newline, but that is not nice for the interfaces).
-
First line (the brief description) must only be one sentence and should start with a capital letter unless it starts with a lowercase symbol or identifier. Don’t use a trailing period either. Don’t exceed 72 characters.
-
The main description (the body) is normal prose and should use normal punctuation and capital letters where appropriate. Consider the commit message as an email sent to the developers (or yourself, six months down the line) detailing why you changed something. There’s no need to specify the how: the changes can be inlined.
-
When committing code on behalf of others use the
--author
option, e.g.git commit -a --author "Joe Coder <[email protected]>"
and--signoff
. -
If your commit is addressing an issue, use the GitLab syntax to automatically close the issue when merging the commit with the upstream repository:
Closes #1234
Fixes #1234
Closes: https://gitlab.gnome.org/GNOME/glib/issues/1234
- If you have a merge request with multiple commits and none of them
completely fixes an issue, you should add a reference to the issue in
the commit message, e.g.
Bug: #1234
, and use the automatic issue closing syntax in the description of the merge request.
Once you're done with your work, you should commit it, push it to a remote repository, and open a Merge Request against the GdkPixbuf upstream repository. Follow the GitLab workflow page on the GNOME wiki for further instructions.
Once you opened a Merge Request, the GdkPixbuf maintainers will review your contribution.
├── build-aux
├── docs
├── gdk-pixbuf
│ └── pixops
├── m4
├── po
├── tests
│ └── test-images
│ ├── fail
│ ├── randomly-modified
│ └── reftests
│ └── tga
└── thumbnailer
build-aux
: Ancillary files, necessary to build GdkPixbufdocs
: The GdkPixbuf API referencegdk-pixbuf
: The core GdkPixbuf sourcepixops
: Platform-specific code for pixel operationspo
: Localization filestests
: Test suitetest-images
: Reference images for the test suitethumbnailer
: Helper binary for generating thumbnails with GdkPixbuf
GdkPixbuf is divided into logical sections:
- Core: the GdkPixbuf object and its properties
- Construction: creating a new GdkPixbuf instance from a buffer
- I/O: Loading and Saving image data in different formats
- Image transformations: Scaling and compositing image data inside GdkPixbuf instances
- The GdkPixbuf loader API, for incremental asynchronous loading of image data in a GdkPixbuf
- The loadable module interface for writing out of tree image loaders
- The animated image API, for image formats that support animations