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komorebi/docs/usage/wallpapers.md
T
LGUG2Z 2b116ea2a3 feat(kwin): wallpapers for monitors and workspaces
Plasma keeps one wallpaper for each screen, not for each virtual desktop, so a
workspace that wants a picture of its own has nowhere to keep it in the shell.
komorebi sets the wallpaper of a screen when a workspace comes into view: the
workspace's own, else its monitor's. It does so however the workspace came into
view (a komorebic command, a pager, an application raising a window) and for the
workspace in front when it starts. A monitor and a workspace with no wallpaper
are left alone.

The Plasma shell sets it over D-Bus, with the call plasma-apply-wallpaperimage
makes, but for one screen. Backend::set_wallpaper asks for it every time a
workspace comes into view, and the KWin backend asks the shell what the screen
shows first, so a picture the user changed by hand is put back and one that is
already right is not touched. The request runs in the background, so switching
workspaces never waits for the shell, and goes on trying for about half a minute
when the shell is not up yet.

A wallpaper also gives the borders the colors of the palette made from its
picture, unless it says generate_theme is false, and theme_options choose the
variant and the color each border takes. The colors change before the workspace
is shown, so its borders are right at once.

komorebi.json takes the wallpaper of a monitor and the wallpaper of a workspace,
and a file that is read again shows the wallpaper of the workspace each monitor
has in front at once. vm-wallpaper runs against the real shell: set at start and
by workspace, a switch komorebi did not make, the colors of the borders, a
wallpaper changed by hand, the palette cache, and komorebi that starts before
the shell.
2026-10-28 07:20:49 -07:00

3.6 KiB

Wallpapers

A monitor, or a workspace of it, can have a wallpaper: the picture the monitor shows while that workspace is in front. A workspace's own wallpaper is shown instead of its monitor's, and a workspace that has none shows its monitor's. komorebi sets the wallpaper when a workspace comes into view, however it comes: a komorebic command, or a pager, a shortcut, or an application raising a window of another workspace. It sets it when it starts too, for the workspace that is in front. A monitor and a workspace with no wallpaper are left alone.

Plasma keeps one wallpaper for each screen, not for each virtual desktop, so komorebi changes the screen's wallpaper as its workspace changes, as komorebi does on Windows and macOS.

Setting wallpapers

The wallpapers are in komorebi.json (Configuration): a wallpaper in the entry of a monitor and one in the entry of a workspace. The first entry of monitors is the first monitor, and so on; the entries of workspaces are the workspaces of that monitor, in order. A file that is read again, because it changed, shows the new wallpaper of the workspace in front at once.

{
  "monitors": [
    {
      "wallpaper": { "path": "~/Pictures/dunes.png" },
      "workspaces": [
        { "name": "code" },
        { "name": "chat",
          "wallpaper": { "path": "~/Pictures/sea.png",
                         "theme_options": { "theme_variant": "Light", "single_border": "Base09" } } }
      ]
    }
  ]
}

A path may start with ~ or have environment variables in it ($HOME), and may have spaces in it. The picture fills the screen and is cropped where it does not fit. The monitor has the dunes.png of the example, and the second workspace has sea.png.

A request for a wallpaper never holds up komorebi: switching workspaces does not wait for the Plasma shell. The shell is asked what the screen shows before it is told anything, so a wallpaper you changed by hand is put back when its workspace is shown again, and a wallpaper that is already right is not touched.

The colors of the borders

A wallpaper also gives the borders their colors, unless it says "generate_theme": false. The palette of the picture, made by the generator komorebi for Windows uses, is a Base16 theme, so the borders of a workspace with a warm picture are warm and those of a workspace with a cool picture are cool (Themes has what the six kinds of border take by default). They change with the workspace, so the colors are right when the workspace comes into view.

theme_options choose the variant of the palette, "theme_variant": "Dark" (the default) or "Light", and which color of the palette each kind of border takes, single_border, stack_border, monocle_border, floating_border, unfocused_border and unfocused_locked_border, each one of Base00 to Base0F. bar_accent is read and not used: there is no komorebi bar here.

A palette takes seconds to make for a large picture, so each one is kept in $XDG_CACHE_HOME/komorebi (~/.cache/komorebi), in a file named for the picture, a hash of its path, size and time of last change, and the variant. A picture with fewer than eight colors has no palette: its wallpaper is set, and the borders keep the colors they had.

When the Plasma shell is not there

The shell is another process, and komorebi may start before it does. komorebi asks again for about half a minute, with longer waits between the tries, and then says once, in its log, that it is leaving wallpapers alone until the shell answers. A session with no Plasma shell has no wallpapers to set, and nothing else in komorebi is affected.