Chapter 7. Customizing desktop appearance and branding

As a system administrator, you can configure the default appearance and branding of the GNOME interface for all users on the system.

7.1. Customizing desktop backgrounds

As a system administrator, you can configure the default desktop background, add extra backgrounds, or add multiple backgrounds available to all users of the system.

If the users are not permitted to change background from the defaults, you must lock the settings using the locks directory. Otherwise, each user can customize the background according to their preferences.

7.1.1. 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.

Procedure

  1. Create a local database for machine-wide settings in /etc/dconf/db/local.d/00-background:

    [org/gnome/desktop/background]
    
    picture-uri='file:///usr/local/share/backgrounds/wallpaper.jpg' 1
    picture-options='scaled' 2
    primary-color='000000' 3
    secondary-color='FFFFFF' 4
    1
    Specify the path to the desktop background image file.
    2
    Specify one of the rendering options for the background image:
    • none
    • wallpaper
    • centered
    • scaled
    • stretched
    • zoom
    • spanned
    3
    Specify the left or top color when drawing gradients or the solid color.
    4
    Specify the right or bottom color when drawing gradients.
  2. Optional: If you want to prevent a user from changing 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
  3. Update the system databases:

    # dconf update
  4. Users must log out and back in again before the system-wide settings take effect.

7.1.2. Adding extra backgrounds

You can make extra backgrounds available to users on your system.

Procedure

  1. Create the /usr/share/gnome-background-properties/extra-backgrounds.xml file.
  2. In the new file, specify the extra background files and their appearance in the following format:

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE wallpapers SYSTEM "gnome-wp-list.dtd">
    <wallpapers>
      <wallpaper deleted="false">
        <name>Background name</name>
        <filename>full-path-to-the-image</filename>
        <options>display-option</options>
        <shade_type>background-shade</shade_type>
        <pcolor>primary-color</pcolor>
        <scolor>secondary-color</scolor>
      </wallpaper>
    </wallpapers>
  3. The new backgrounds are now available to all users in the Background section of the Settings application.

7.1.3. Frequently used background schema keys

The following configuration controls the behavior of desktop backgrounds in the GSettings system.

Table 7.1. Frequently used GSettings and XML background keys

Key nameXML namePossible valuesDescription

picture-options

options

  • none
  • wallpaper
  • centered
  • scaled
  • stretched
  • zoom
  • spanned

Determines how the image set by wallpaper_filename is rendered.

color-shading-type

shade_type

  • horizontal
  • vertical
  • solid

Determines the shade of the background color.

primary-color

pcolor

default: #023c88

Left or Top color when drawing gradients, or the solid color.

secondary-color

scolor

default: #5789ca

Right or Bottom color when drawing gradients, not used for solid color.

Example 7.1. An 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>

Example 7.2. An extra backgrounds file with two <wallpaper> elements

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.

<?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>

7.1.4. Setting the screen shield

Screen shield is the screen that slides down when you lock the system. You can set a default screen shield picture for all users on the system.

Procedure

  1. Create the /etc/dconf/db/gdm.d/01-screensaver file:

    [org/gnome/desktop/screensaver]
    picture-uri='file:///opt/corp/background.jpg'

    Replace /opt/corp/background.jpg with the absolute path to the image file that you want to use as the default screen shield. Supported formats are PNG, JPG, JPEG, and TGA. Note that the screen shield scales your image if necessary to fit the screen.

  2. Update the system databases:

    # dconf update
  3. Users must log out and back in again before the system-wide settings take effect.

Troubleshooting

  • If the screen shield does not update:

    1. Verify that you have updated the system databases:

      # dconf update
    2. Try restarting GDM:

      # systemctl restart gdm.service
      Warning

      Restarting the gdm service terminates all currently running GNOME sessions of all desktop users who are logged in. This might result in users losing unsaved data.

7.2. Customizing the branding of the login screen

You can change the logo that appears on the GNOME login screen (GDM) using a dconf profile.

Prerequisites

  • Prepare an image file in any of the supported formats: ANI, BPM, GIF, GTIFF, ICNS, ICO, JPEG, JPEG 2000, PCX, PNM, PBM, PGM, PPM, RAS, SVG, TGA, TIFF, WBMP, XBM, or XPM.
  • The image must be around 48 pixels in height. If it is significantly larger, it will exceed the logo area.
  • Store the image file in a location that the gdm user can access. For example, select a universally readable system directory such as /opt/ or /usr/local/.

Procedure

  1. Create the /etc/dconf/db/gdm.d/01-override-logo configuration file with the following content:

    [org/gnome/login-screen]
    logo='/path/to/logo.png'

    Replace /path/to/logo.png with the full path to the image file that you want to use as the login screen logo.

  2. Update the system databases:

    # dconf update

Verification

  1. Log out or otherwise switch to the login screen.
  2. Check if it displays the logo that you selected.
  3. If the logo does not update, restart GDM:

    # systemctl restart gdm
    Warning

    Restarting the gdm service terminates all currently running GNOME sessions of all desktop users who are logged in. This might result in users losing unsaved data.