Throne (Window Manager Ruler)

Automatically applies window manager properties when applications open.

Requirements

uv add python-xlib tomli        # tomli only needed on Python < 3.11
sudo apt install wmctrl xdotool x11-utils  # x11-utils provides xprop

Usage

# Install config
mkdir -p ~/.config/throne
cp rules.example.toml ~/.config/throne/rules.toml

# Run
python throne.py

To run on login, add to your session autostart (e.g. ~/.xprofile or a systemd user service).

Identifying a window's class

Run this, then click the target window:

xprop WM_CLASS

Output looks like: WM_CLASS(STRING) = "instance", "ClassName" — use either value in match.class.

To inspect a running window interactively:

xwininfo        # click a window, shows window ID
xprop -id 0x… WM_CLASS _NET_WM_NAME _NET_WM_PID

Rules

Config lives at ~/.config/throne/rules.toml. Rules are evaluated in order; all matching rules apply.

[[rules]]
match.class = "zoom"           # match on WM_CLASS (instance or class name, case-insensitive, globs ok)
match.title = "*meeting*"      # match on window title (glob, case-insensitive)
match.executable = "obs"       # match on process executable name
actions = ["always_on_top"]

All match fields are optional and ANDed together. Globs (*, ?) are supported in all fields.

Actions

Stacking

| Action | Effect | |---|---| | always_on_top | Keep window above all others | | always_on_bottom | Keep window below all others |

Visibility

| Action | Effect | |---|---| | sticky | Show on all workspaces | | skip_taskbar | Hide from taskbar/dock | | skip_pager | Hide from workspace pager | | fullscreen | Make fullscreen |

Size & position

| Action | Effect | |---|---| | maximize | Maximize horizontally and vertically | | maximize_vertical | Maximize vertically only | | maximize_horizontal | Maximize horizontally only | | shade | Roll up to title bar | | minimize | Minimize/iconify on open | | geometry=WxH+X+Y | Set size and position, e.g. geometry=800x600+100+50 | | workspace=N | Move to workspace N (1-indexed) |

Focus

| Action | Effect | |---|---| | focus | Focus window on open |

Appearance

| Action | Effect | |---|---| | opacity=0.0–1.0 | Set window opacity, e.g. opacity=0.85 |

Config reload

throne watches the config file and reloads it automatically when it changes — no restart needed.

Debugging

throne logs matched rules and errors to stdout/stderr. To watch what classes windows have as they open:

xdotool search --onlyvisible --name "" getwindowclassname %@

Or watch live with:

while true; do xdotool getactivewindow getwindowclassname 2>/dev/null; sleep 1; done