How to refresh the desktop background in various desktop environments? [closed]

Question

In XFCE 4.10 I can refresh my desktop background with xfdesktop --reload.

I would like to know how I can do the same for as many as possible other desktop environments (Unity, KDE, LXDE, Mate, Cinnamon, GNOME2, GNOME3,...).

Answer 1

Here is a code example which detects the desktop the environment and reloads the dynamic wallpaper background explicitly when required by the detected desktop environment.

The code should work with GNOME 3, KDE 4, Unity and XFCE. Tested answers with solutions for other desktop environments are welcomed and will be up-voted.

if [ "$XDG_CURRENT_DESKTOP" = '' ]
then
  DESKTOPENV=$(echo "$XDG_DATA_DIRS" | sed 's/.*\(xfce\|kde\|gnome\).*/\1/')
else
  DESKTOPENV=$XDG_CURRENT_DESKTOP
fi
DESKTOPENV=${DESKTOPENV,,}  # convert to lower case

case $DESKTOPENV in
  'gnome') {
    gsettings set org.gnome.desktop.background picture-uri file:///tmp/wallpaper.png'  # GNOME 3 only
    };;
  'kde') {
    :
    };;
  'unity') {
    :
    };;
  'xfce') {
    xfdesktop --reload
    };;
esac

Answer 2

You can set the content of the root window (i.e. the background) independently of the window manager or desktop environment. The traditional utility xsetroot only supports a solid color or a black-and-white image. Many image viewing programs can load a color image in popular bitmap formats to the root window, for example the xsetbg utility from Xloadimage or the display utility from ImageMagick or GraphicsMagick.

xsetbg /path/to/image.png
display -window root /path/to/image.png
gm display -window root /path/to/image.png

This doesn't affect your desktop environment's notion of the wallpaper, so it may decide to display its own content in place of yours from time to time.