picom
standalone X11 compositor for shadows, transparency, blur, and fades
TLDR
SYNOPSIS
picom [options]
DESCRIPTION
picom is a lightweight standalone X11 compositor — it paints the final image you see by combining window contents drawn into offscreen pixmaps, which lets it add effects that the window manager itself does not render: shadows, fades, blur behind transparency, rounded corners (v10+), and animations. It is typically started alongside a tiling/stacking WM that is not itself a compositor (i3, bspwm, Openbox, awesome, Xmonad).Most real configuration lives in `picom.conf`. Command-line flags override config values and are handy for testing.
PARAMETERS
-b, --daemon
Run as a daemon (fork into background).--config FILE
Path to the configuration file (default `~/.config/picom/picom.conf`).--backend TYPE
Rendering backend: `glx`, `xrender`, or `xrglxhybrid` (legacy). Modern picom also supports the Vulkan backend on some builds.--experimental-backends
Use the rewritten backend implementations. Required on older releases for features like `dual_kawase` blur. Not needed on picom ≥ 10, where the new backends are the default.--shadow / --no-shadow
Enable or disable drop shadows.--fading / --no-fading-openclose
Enable fades on window open/close or disable them specifically on open/close.--fade-in-step N / --fade-out-step N
Opacity step per frame when fading (0.001–1.0).-i OPACITY, --inactive-opacity OPACITY
Default opacity for inactive windows (0.0–1.0).-e OPACITY, --frame-opacity OPACITY
Opacity for window frames.--active-opacity OPACITY
Opacity for the focused window.--blur-method METHOD
Blur algorithm: `none`, `gaussian`, `box`, `kernel`, `dual_kawase`.--blur-background
Blur the background behind transparent windows.--vsync
Enable vsync using the appropriate method for the selected backend.--use-damage / --no-use-damage
Render only damaged regions (faster, default on).--unredir-if-possible
Unredirect fullscreen windows (e.g. full-screen video/games) for better performance.--corner-radius N
Round window corners with radius N pixels (picom ≥ 10).--shadow-radius N / --shadow-offset-x N / --shadow-offset-y N / --shadow-opacity O
Shape, offset, and opacity of drop shadows.--log-level LEVEL
`trace`, `debug`, `info`, `warn`, `error`, `fatal`.--log-file FILE
Write logs to FILE instead of stderr.-v, --version
Show version.-h, --help
Show help.
CAVEATS
Only works under X11 (Wayland compositors render themselves). Requires a GPU driver with working GLX for the `glx` backend; VirtualBox/VMware guests often need `xrender`. Conflicts with other compositors (including KWin and Mutter) — stop them first. Effects are resource-intensive on old hardware; disable blur and shadows if the CPU/GPU can't keep up.
HISTORY
picom is a maintained fork of compton, itself a fork of xcompmgr-dana/xcompmgr. Maintained by yshui after compton became inactive, picom is now the community-standard compositor for tiling WMs.
