README for desktop-base
=======================

1. What’s provided
   1.1. Themes packs
   1.2. Debian logos
   1.3. Desktop files
   1.4. Default configurations overrides
   1.5. Plymouth boot splashes
2. How to switch themes
   2.1. Global theme alternative
   2.2. Individual alternatives
3. Theme pack structure
4. Contributing
   4.1. Artists
   4.2. Desktop environment maintainers
   4.3. Notes and references


1. What’s provided

1.1. Theme packs

Four theme packs are currently provided:
- Soft Waves (default for Stretch)
- Lines (default for Jessie)
- Joy (default for Wheezy)
- Spacefun (default for Squeeze)

    These themes contain customization for GRUB, Plymouth, login managers like
SDDM and LightDM, wallpapers and lock screen for desktop environments like
GNOME, KDE’s Plasma 5, Xfce, Mate…
See below for how to switch between themes and a detailed description of the
theme packs structure.

1.2. Debian logos

Several sizes of the Debian logo are shipped as:
    /usr/share/icons/hicolor/${size}x${size}/emblems/emblem-debian.${ext}
    /usr/share/icons/hicolor/${size}x${size}/emblems/emblem-debian.icon

    The sizes currently provided are 36, 64, 128 as PNG, and scalable for the
SVG version. Each has a side .icon descriptor file.

A Debian security logo is also shipped in:
    /usr/share/pixmaps/debian-security.png

1.3. Desktop files

/usr/share/desktop-base/debian-homepage.desktop
/usr/share/desktop-base/debian-reference.desktop
/usr/share/desktop-base/debian-security.desktop

1.4. Default configurations overrides

    desktop-base ships different files to override default theme configurations
of various parts of the system and prefer the active Debian theme.
See below « How to switch themes » for directions on how to configure these
overridden defaults.

- GRUB background and menu colors:
    /usr/share/desktop-base/grub_background.sh

    This alternative is used by /etc/grub.d/05_debian_theme provided by
grub-common to correctly update the GRUB background with the Debian theme when
running « update-grub ».

- GNOME desktop wallpaper and lock screen:
    /usr/share/glib-2.0/schemas/10_desktop-base.gschema.override

- Plasma 5 desktop wallpaper:
    /usr/share/plasma/shells/org.kde.plasma.desktop/contents/updates/desktop-base.js

    Plasma ensures this JavaScript script is run for every user once and only
once for each Plasma version. It is run at user login time. See:
https://userbase.kde.org/KDE_System_Administration/PlasmaDesktopScripting

1.5. Plymouth boot splashes

    desktop-base ships several Plymouth themes. To activate the default theme,
install the plymouth and plymouth-themes packages and run:
    plymouth-set-default-theme softwaves

and update the initrd by running:
    update-initramfs -u

    Then remember to add “splash” to your kernel command line.
To do that permamently, edit /etc/default/grub and add splash to the
GRUB_CMDLINE_LINUX_DEFAULT variable. For example:
    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"


2. How to switch themes

2.1. Global theme alternative

    The package provides a global alternative to switch themes all relevant
elements to a given theme.
This alternative is called « desktop-theme » and currently supports GRUB
background, login manager background (SDDM, LightDM), Desktops wallpapers
(GNOME, Plasma 5, Xfce, Mate…).

You can change the theme pack selection with:
    update-alternatives --config desktop-theme

Following a theme switch you’ll also need to run the GRUB menu update command:
    update-grub

Plymouth theme switching is currently not supported inside theme packs so
you’ll have to do it by hand for now with plymouth-set-default-theme command.

2.2. Individual alternatives

    In addition do the global theme alternative, desktop-base provides a series
of finer grained alternatives to override specific elements of the theme packs.

Each alternative can be switched with:
    update-alternative --config ${alternative-name}
Selecting 0 will revert to the initial default of an alternative.

Additional alternatives can be added with:
    update-alternatives --install ${target-file} \
        ${alternative-name} \
        ${alternative-file} ${priority}
You may check the desktop-base postinst script for examples.

The list of alternatives provided by desktop-base is explained below:

- desktop-grub, alternative for:
    /usr/share/images/desktop-base/desktop-grub.png
- desktop-grub.sh (sub-alternative of desktop-grub), alternative for:
    /usr/share/desktop-base/grub_background.sh

    The desktop-grub PNG file is used by the update-grub script to define the
background for the GRUB boot menu.
It defaults to the active theme selected via the desktop-theme alternative,
and on top of that:
- To the 16x9 / 1920x1080 version of the background for systems where EFI is
  in use (grub-efi installed).
- To the 4x3 / 640x480 version otherwise.
    It’s possible to override this default behaviour by selecting the other
ratio alternative pointing to /usr/share/desktop-base/active-theme/grub/*
while still keeping the GRUB background automatically switching via the global
desktop-theme alternative.

    The desktop-grub.sh script is sourced by update-grub to read the path to
the background image and the menu colors to be used for grub.

- desktop-login-background, alternative for:
    /usr/share/desktop-base/active-theme/login/background.svg

    This alternatives switches the login background for LightDM (default) and
SDDM when the SDDM theme debian-theme is used (default when there’s no SDDM
conf file). It defaults to the login background of the active theme selected
via the desktop-theme alternative.

- desktop-background, alternative for:
    /usr/share/images/desktop-base/desktop-background

    This is a single SVG file used by desktop environments that don’t require
a more complex wallpaper setup (Xfce, MATE…).
It defaults to the 1920x1080 version of the active theme wallpaper selected
via the desktop-theme alternative.

- desktop-background.xml, alternative for:
    /usr/share/images/desktop-base/desktop-background.xml
- desktop-lockscreen.xml, alternative for:
    /usr/share/images/desktop-base/desktop-lockscreen.xml

    These two XML files are used by GNOME to set the wallpaper and lock screen
for all users who didn’t otherwise chose a wallpaper or lock screen themselves.
It defaults to the wallpaper and lock screen for the active theme selected via
the desktop-theme alternative.

- desktop-plasma5-wallpaper, alternative for:
    /usr/share/wallpapers/DebianTheme

    This alternative folder is used by Plasma 5 in Debian to select the
wallpaper for all users who didn’t otherwise select a wallpaper themselves. It
defaults to the wallpaper of the active theme selected via the desktop-theme
alternative.


3. Theme pack structure

    A certain theme pack structure is expected in order to provide drop-in
replacements for the default Debian theme that can be switched globally with
the desktop-theme alternative. This paragraph describes the structure to mimic
if you want to provide additional theme packs for Debian.

A theme pack should contain the following elements:

-> A section in the global package Makefile.
       You should be able to copy the section for an existing theme, just take
   care to replace all theme name occurrences with that of your new theme.
       At some point it would be desirable to have the Makefile parts inside
   each theme’s folders so the themes can be self contained, and the main
   Makefile will only have to detect the themes present in the sources.
 
./grub/Makefile
./grub/grub-4x3.svg
./grub/grub-16x9.svg
-> SVG and Makefile used to produce the GRUB background images. The Makefile
   can be copy-pasted from and existing theme pack and should generate the
   PNGs corresponding to each SVG in the GRUB folder.
   For best compatibility grub-4x3.svg should generate a 640x480 PNG for used
   by system with classical BIOS. grub-16x9.svg should generate 1920x1080 PNG
   for used by more recent EFI firmwares.
./grub/grub_background.sh
-> Shell file containing variables to configure GRUB. This file is sourced
   when running « update-grub ».

./plymouth/debian.png
./plymouth/logo.png
…
-> Assets used in the Plymouth splash screen
./plymouth/${theme}.plymouth
-> Descriptor file for the Plymouth theme, a bit like .desktop files for
   applications. Copy and adapt to your needs.
./plymouth/${theme}.script
-> Script handling everything plymouthy when splash is activated, from just
   after grub to display manager. It’s a massive amount of work to get
   everything right, including encrypted partitions password input, system
   messages, fsck feedback… so it’s highly recommended to start with an
   existing script and adapt the background setup and animation to the needs
   of your theme.

./login/background.svg
-> To provide the login background alternative for LightDM, SDDM…

./gnome-wp-list.xml
-> To make the wallpaper and lock screen selectable in GNOME preferences.
   This file describes a list of XML files, one for each image packs provided.
   GNOME uses these image packs to select the most appropriate version of a
   wallpaper depending on the user’s screen resolution.

./wallpaper/gnome-background.xml
./wallpaper/contents/images/2560x1440.svg
./wallpaper/contents/images/1280x720.svg
./wallpaper/contents/images/1920x1200.svg
./wallpaper/contents/images/1920x1080.svg
./wallpaper/contents/images/1280x800.svg
./wallpaper/contents/images/2560x1600.svg
…
./wallpaper/metadata.desktop
-> Wallpaper image pack, similar to the lock screen pack described above.

./lockscreen/gnome-background.xml
./lockscreen/contents/images
./lockscreen/contents/images/2560x1440.svg
./lockscreen/contents/images/1280x720.svg
./lockscreen/contents/images/1920x1080.svg
…
./lockscreen/metadata.desktop
-> Lock screen background image pack.
   The gnome-background.xml describes the available resolutions for the image,
   for use by GNOME.
   The metadata.desktop contains the description and license of the image pack
   for use by Plasma 5.
   The various files in the images folder are the provided resolutions and
   ratio of the image. They can be either PNG or SVG, and should be name
   according to their width and height as the example above so that Plasma 5
   can select the correct version.
   There is no strict rule on which resolution and ratio should be provided
   and a single version could suffice as long as it’s appearance is not broken
   when cropped at different resolutions.

./sources
-> Additional sources for theme elements that are not shipped as SVG in the
   binary package, or for visuals not strictly related to the desktop theme
   (CD covers, t-shirts…).


4. Contributing

4.1. Artists

We need professional looking Debian artwork in the Desktop. If you want to
help improve themes in Debian or provide additional theme proposals, you
should monitor the Wiki page for artwork contests we run for each new Debian
release:
https://wiki.debian.org/DebianArt/Themes

The debian-desktop mailing list (see below) is also a low-traffic source of
information about what’s going on with desktop themes in Debian.

If you’ve suggestions for a better artwork, create or edit the images and open
a 'wishlist' bug against desktop-base in our Bug Tracking System
(https://bugs.debian.org/). Please attach the source file, preferably in SVG or
XCF format, and only propose work for which you’re the author.

For us to be able to distribute your work in Debian, it will need to be under
a free and open source licenses which permits reuse and modifications as
required by the Debian Free Software Guidelines.

See a more complete list of requirements here:
https://wiki.debian.org/DebianDesktop/Artwork/Requirements

4.2. Desktop environment maintainers

desktop-base is used by GNOME, KDE’s Plasma 5, Xfce, Mate…

If you’re responsible for a desktop environment in Debian and want to use
desktop-base artwork, improve the support for your DE, or add additional
theming options use the layout described above and send your patch through the
Bug Tracking System, or ping us on debian-desktop@lists.debian.org.

We’re glad to help with theme packaging and improving the consistency of
Debian themes over the desktop environments available in the archive.

4.3. Notes and references

If you’re interested in working on Debian theming, you may be interested in
the following references.

- Information about the Debian Logo:
https://www.debian.org/logos/
https://wiki.debian.org/DebianLogo

- Archive and subscriptions to the debian-desktop mailing list:
https://lists.debian.org/debian-desktop/

