transset

Set window transparency by clicking

$ transset [0.8]

$ transset -i [0x1400003] [0.75]

$ transset -t

$ transset --inc [0.1]

$ transset --dec [0.1]

$ transset -a [0.9]

transset [options] [opacity]

transset sets window transparency in X11 by modifying the NETWMWINDOWOPACITY property on windows. The opacity value ranges from 0 (fully transparent) to 1 (fully opaque), with 0.75 as the default.
The tool requires a compositing window manager (such as picom, xcompmgr, KWin, or Mutter) to actually render the transparency. Without a compositor, the property is set but no visual effect occurs.
By default, transset enters interactive mode where clicking on a window sets its transparency. Window ID or name options allow non-interactive scripted use.

-i, --id id

Select window by X window ID.

Select window by name.

Toggle between current opacity and fully opaque.

Increase opacity by specified amount.

Decrease opacity by specified amount.

Apply to all windows.

Select window under pointer (default).

Print verbose output.

Display version.

Requires a running compositing manager for visible effects. X11 only; does not work on Wayland. Some applications may not respect transparency settings. Window IDs change between sessions.

transset was developed as part of the X.Org project to demonstrate and utilize the COMPOSITE extension. The transset-df variant by Daniel Forchheimer added command-line options for scripted use without interactive clicking.

xwininfo(1), picom(1), xcompmgr(1), xprop(1)