Chapter 8. Customizing desktop appearance
This section explains how system administrators can customize appearance of the desktop environment for different users of the system.
8.1. Customizing desktop backgrounds
As a system administrator, you can configure the default desktop background, add extra backgrounds, or add multiple backgrounds using the dconf utility.
If the users of the system are not permitted to change background from the defaults, system administrator needs to lock the settings using the locks
directory. Otherwise, each user can customize the background according to their preferences.
8.1.1. Customizing the default desktop background
You can configure the default desktop background and its appearance by setting the relevant GSettings keys in the org.gnome.desktop.background
schema.
For more information about GSettings, see Section 6.1, “Introduction to configuring GNOME”.
Use the following procedure to set the default background:
Procedure
Create a local database for machine-wide settings in
/etc/dconf/db/local.d/00-background
:# Specify the dconf path [org/gnome/desktop/background] # Specify the path to the desktop background image file picture-uri='file:///usr/local/share/backgrounds/wallpaper.jpg' # Specify one of the rendering options for the background image: # 'none', 'wallpaper', 'centered', 'scaled', 'stretched', 'zoom', 'spanned' picture-options='scaled' # Specify the left or top color when drawing gradients or the solid color primary-color='000000' # Specify the right or bottom color when drawing gradients secondary-color='FFFFFF'
Optionally, if you want a user to not be able to change the default background, override the user’s setting in the
/etc/dconf/db/local.d/locks/background
file:# List the keys used to configure the desktop background /org/gnome/desktop/background/picture-uri /org/gnome/desktop/background/picture-options /org/gnome/desktop/background/primary-color /org/gnome/desktop/background/secondary-color
Update the system databases:
# dconf update
- Users must log out and back in again before the system-wide settings take effect.
8.1.2. Adding extra backgrounds
You can make extra backgrounds available to users on your system.
Procedure
Use the
org.gnome.desktop.background
schemas to create a file in thexml
format specifying your extra background’s appearance.Table 8.1. Frequently used org.gnome.desktop.background schemas GSettings Keys
Key Name Possible Values Description picture-options
"none", "wallpaper", "centered", "scaled", "stretched", "zoom", "spanned"
Determines how the image set by wallpaper_filename is rendered.
color-shading-type
"horizontal", "vertical", and "solid"
Determines shade the background color.
primary-color
default: #023c88
Left or Top color when drawing gradients, or the solid color.
secondary-color
default: #5789ca
Right or Bottom color when drawing gradients, not used for solid color.
The full range of options can be found in the dconf-editor GUI or the gsettings command-line utility. For more information, see Section 6.3, “Displaying GSettings values for desktop applications”.
-
Store the *.xml file under the
/usr/share/gnome-background-properties/
directory.
When a user clicks their name in the top right corner, chooses Settings
, and in the Personal
section of the table selects Background
, they will see the new background available.
Example implementation of org.gnome.desktop.background GSettings keys
An example extra backgrounds file with one <wallpaper>
element
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE wallpapers SYSTEM "gnome-wp-list.dtd"> <wallpapers> <wallpaper deleted="false"> <name>Company Background</name> <name xml:lang="de">Firmenhintergrund</name> <filename>/usr/local/share/backgrounds/company-wallpaper.jpg</filename> <options>zoom</options> <shade_type>solid</shade_type> <pcolor>#ffffff</pcolor> <scolor>#000000</scolor> </wallpaper> </wallpapers>
In one configuration file, you can specify multiple <wallpaper>
elements to add more backgrounds as shown in the following example with two <wallpaper>
elements, adding two different backgrounds.
An example extra backgrounds file with two <wallpaper>
elements
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE wallpapers SYSTEM "gnome-wp-list.dtd"> <wallpapers> <wallpaper deleted="false"> <name>Company Background</name> <name xml:lang="de">Firmenhintergrund</name> <filename>/usr/local/share/backgrounds/company-wallpaper.jpg</filename> <options>zoom</options> <shade_type>solid</shade_type> <pcolor>#ffffff</pcolor> <scolor>#000000</scolor> </wallpaper> <wallpaper deleted="false"> <name>Company Background 2</name> <name xml:lang="de">Firmenhintergrund 2</name> <filename>/usr/local/share/backgrounds/company-wallpaper-2.jpg</filename> <options>zoom</options> <shade_type>solid</shade_type> <pcolor>#ff0000</pcolor> <scolor>#00ffff</scolor> </wallpaper> </wallpapers>
8.1.3. Setting the screen shield
Screen shield is the screen that quickly slides down when the system is locked. It is controlled by the org.gnome.desktop.screensaver.picture-uri
GSettings key. GDM uses its own dconf profile, so you can set the default background by changing the settings in that profile.
For more information on GSettings and dconf, see Section 6.1, “Introduction to configuring GNOME”.
Procedure
Create a gdm database for machine-wide settings in
/etc/dconf/db/gdm.d/01-screensaver
:[org/gnome/desktop/screensaver] picture-uri='file:///opt/corp/background.jpg'
Replace
/opt/corp/background.jpg
with the path to the image file you want to use as the screen shield. Supported formats are PNG, JPG, JPEG, and TGA. Note that the image will be scaled if necessary to fit the screen.Update the system databases:
# dconf update
- Users must log out and back in again before the system-wide settings take effect.
Troubleshooting
If the screen shield does not update, you can:
-
Make sure that you have updated the system databases by running the
dconf update
command as theroot
user. - Try restarting GDM.
8.2. Using GNOME Shell extensions to customize desktop environment
GNOME Shell extensions allow for the customization of the default GNOME Shell interface and its parts, such as window management and application launching.
Before deploying third-party GNOME Shell extensions on Red Hat Enterprise Linux, make sure to read the following document to learn about the Red Hat support policy for third-party software: How does Red Hat Global Support Services handle third-party software, drivers, and/or uncertified hardware/hypervisors?
8.2.1. Overview of GNOME Shell extensions
This section provides an overview of GNOME Shell extensions available on RHEL 8, including the name of the package providing a particular extension, and the description of what each extension does.
Table 8.2. Overview of available GNOME Shell extensions
Package name | Extension name | Description |
---|---|---|
gnome-shell-extension-apps-menu | apps-menu | Applications menu for GNOME Shell |
gnome-shell-extension-top-icons | Top Icons | Show legacy icons on top |
gnome-shell-extension-user-theme | user-theme | Support for custom themes in GNOME Shell |
gnome-shell-extension-drive-menu | drive-menu | Drive status menu for GNOME Shell |
gnome-shell-extension-window-list | window-list | Display a window list at the bottom of the screen in GNOME Shell |
gnome-shell-extension-dash-to-dock | Dash to Dock | Dock for the Gnome Shell by micxgx.gmail.com |
gnome-shell-extension-desktop-icons | Desktop Icons | Desktop icons support for the GNOME Classic experience |
gnome-shell-extension-no-hot-corner | nohotcorner | Disable the hot corner in GNOME Shell |
gnome-shell-extension-systemMonitor | systemMonitor | System Monitor for GNOME Shell |
gnome-shell-extension-updates-dialog | Updates Dialog | Show a modal dialog when there are software updates |
gnome-shell-extension-window-grouper | window-grouper | Keep windows that belong to the same process on the same workspace |
gnome-shell-extension-panel-favorites | panel-favorites | Favorite launchers in GNOME Shell’s top bar |
gnome-shell-extension-windowsNavigator | windowNavigator | Support for keyboard selection of windows and workspaces in GNOME shell |
gnome-shell-extension-auto-move-windows | Autom Move Windows | Assign specific workspaces to applications in GNOME Shell |
gnome-shell-extension-launch-new-instance | launch-new-instance | Always launch a new application instance for GNOME Shell |
gnome-shell-extension-workspace-indicator | workspace-indicator | Workspace indicator for GNOME Shell |
gnome-shell-extension-disable-screenshield | Disable Screen Shield | Disable GNOME Shell screen shield if lock is disabled |
gnome-shell-extension-native-window-placement | native-window-placement | Native window placement for GNOME Shell |
gnome-shell-extension-screenshot-window-sizer | screenshot-window-sizer | Screenshot window sizer for GNOME Shell |
gnome-shell-extension-horizontal-workspaces | horizontal-workspaces | Desktop icons support for the GNOME Classic experience |
gnome-shell-extension-places-menu | places-menu | Places status menu for GNOME Shell |
gnome-classic-session | – | GNOME Classic mode session |
8.2.2. Enabling machine-wide extensions
Prerequisites
To make extensions available to all users on the system, install them in the /usr/share/gnome-shell/extensions
directory.
Procedure
Create a local database file for machine-wide settings in
/etc/dconf/db/local.d/00-extensions
:[org/gnome/shell] # List all extensions that you want to have enabled for all users enabled-extensions=['myextension1@myname.example.com', 'myextension2@myname.example.com']
The
enabled-extensions
key specifies the enabled extensions using the extensions' UUID (myextension1@myname.example.com
andmyextension2@myname.example.com
).Update the system databases:
# dconf update
Users must log out and back in again before the system-wide settings take effect.
NoteThere is currently no way to enable additional extensions for users who have already logged in. This does not apply for existing users who have installed and enabled their own GNOME extensions.
8.2.3. Locking down enabled extensions
You can prevent the user from enabling or disabling extensions by locking down the org.gnome.shell.enabled-extensions
key.
Procedure
Create a local database file for machine-wide settings in
/etc/dconf/db/local.d/00-extensions
:[org/gnome/shell] # List all extensions that you want to have enabled for all users enabled-extensions=['myextension1@myname.example.com', 'myextension2@myname.example.com']
The
enabled-extensions
key specifies the enabled extensions using the extensions' UUID (myextension1@myname.example.com
andmyextension2@myname.example.com
).Override the user’s setting and prevent the user from changing it in
/etc/dconf/db/local.d/locks/extensions
:# Lock the list of mandatory extensions /org/gnome/shell/enabled-extensions
Update the system databases:
# dconf update
- Users must log out and back in again before the system-wide settings take effect.
After locking down the org.gnome.shell.enabled-extensions
, any extensions installed in ~/.local/share/gnome-shell/extensions
or /usr/share/gnome-shell/extensions
that are not listed in the org.gnome.shell.enabled-extensions
key will not be loaded by GNOME Shell, thus preventing the user from using them.
8.2.4. Setting up mandatory extensions
In GNOME Shell, you can provide a set of extensions that the user has to use.
Prerequisites
The extensions must be installed under the /usr/share/gnome-shell/extensions
directory.
Procedure
Create a local database file for machine-wide settings in
/etc/dconf/db/local.d/00-extensions-mandatory
:[org/gnome/shell] # List all mandatory extensions enabled-extensions=['myextension1@myname.example.com', 'myextension2@myname.example.com']
The
enabled-extensions
key specifies the enabled extensions using the extensions' UUID (myextension1@myname.example.com
andmyextension2@myname.example.com
).Override the user’s setting and prevent the user from changing it in
/etc/dconf/db/local.d/locks/extensions-mandatory
:# Lock the list of mandatory extensions /org/gnome/shell/enabled-extensions
Update the system databases:
# dconf update
- Users must log out and back in again before the system-wide settings take effect.