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PICOM(1) User Commands PICOM(1)


picom - a compositor for X11


picom [OPTIONS]


picom is a compositor based on Dana Jansens' version of xcompmgr (which itself was written by Keith Packard). It includes some improvements over the original xcompmgr, like window frame opacity and inactive window transparency.


-h, --help

Get the usage text embedded in program code, which may be more up-to-date than this man page.

-r, --shadow-radius=RADIUS

The blur radius for shadows, in pixels. (defaults to 12)

-o, --shadow-opacity=OPACITY

The opacity of shadows. (0.0 - 1.0, defaults to 0.75)

-l, --shadow-offset-x=OFFSET

The left offset for shadows, in pixels. (defaults to -15)

-t, --shadow-offset-y=OFFSET

The top offset for shadows, in pixels. (defaults to -15)

-I, --fade-in-step=OPACITY_STEP

Opacity change between steps while fading in. (0.01 - 1.0, defaults to 0.028)

-O, --fade-out-step=OPACITY_STEP

Opacity change between steps while fading out. (0.01 - 1.0, defaults to 0.03)

-D, --fade-delta=MILLISECONDS

The time between steps in fade step, in milliseconds. (> 0, defaults to 10)

-m, --menu-opacity=OPACITY

Default opacity for dropdown menus and popup menus. (0.0 - 1.0, defaults to 1.0)

-c, --shadow

Enabled client-side shadows on windows. Note desktop windows (windows with _NET_WM_WINDOW_TYPE_DESKTOP) never get shadow, unless explicitly requested using the wintypes option.

-C, --no-dock-shadow

Avoid drawing shadows on dock/panel windows. This option is deprecated, you should use the wintypes option in your config file instead.

-f, --fading

Fade windows in/out when opening/closing and when opacity changes, unless --no-fading-openclose is used.


Equals to -f. Deprecated.

-i, --inactive-opacity=OPACITY

Opacity of inactive windows. (0.1 - 1.0, defaults to 1.0)

-e, --frame-opacity=OPACITY

Opacity of window titlebars and borders. (0.1 - 1.0, disabled by default)

-G, --no-dnd-shadow

Don’t draw shadows on drag-and-drop windows. This option is deprecated, you should use the wintypes option in your config file instead.

-b, --daemon

Daemonize process. Fork to background after initialization. Causes issues with certain (badly-written) drivers.


Set the log level. Possible values are "TRACE", "DEBUG", "INFO", "WARN", "ERROR", in increasing level of importance. Case doesn’t matter. If using the "TRACE" log level, it’s better to log into a file using --log-file, since it can generate a huge stream of logs.


Set the log file. If --log-file is never specified, logs will be written to stderr. Otherwise, logs will to written to the given file, though some of the early logs might still be written to the stderr. When setting this option from the config file, it is recommended to use an absolute path.


Use the new, reimplemented version of the backends. The new backends are HIGHLY UNSTABLE at this point, you have been warned. This option is not available in the config file.


Show all X errors (for debugging).

--config PATH

Look for configuration file at the path. See CONFIGURATION FILES section below for where picom looks for a configuration file by default. Use /dev/null to avoid loading configuration file.

--write-pid-path PATH

Write process ID to a file. it is recommended to use an absolute path.

--shadow-red VALUE

Red color value of shadow (0.0 - 1.0, defaults to 0).

--shadow-green VALUE

Green color value of shadow (0.0 - 1.0, defaults to 0).

--shadow-blue VALUE

Blue color value of shadow (0.0 - 1.0, defaults to 0).


Let inactive opacity set by -i override the _NET_WM_OPACITY values of windows.

--active-opacity OPACITY

Default opacity for active windows. (0.0 - 1.0, defaults to 1.0)

--inactive-dim VALUE

Dim inactive windows. (0.0 - 1.0, defaults to 0.0)


Try to detect WM windows (a non-override-redirect window with no child that has WM_STATE) and mark them as active.


Mark override-redirect windows that doesn’t have a child window with WM_STATE focused.


Do not fade on window open/close.


Do not fade destroyed ARGB windows with WM frame. Workaround of bugs in Openbox, Fluxbox, etc.


Do not paint shadows on shaped windows. Note shaped windows here means windows setting its shape through X Shape extension. Those using ARGB background is beyond our control. Deprecated, use --shadow-exclude 'bounding_shaped' or --shadow-exclude 'bounding_shaped && !rounded_corners' instead.


Try to detect windows with rounded corners and don’t consider them shaped windows. The accuracy is not very high, unfortunately.


Detect _NET_WM_OPACITY on client windows, useful for window managers not passing _NET_WM_OPACITY of client windows to frame windows.

--refresh-rate REFRESH_RATE

Specify refresh rate of the screen. If not specified or 0, picom will try detecting this with X RandR extension.

--vsync, --no-vsync

Enable/disable VSync.


Limit picom to repaint at most once every 1 / refresh_rate second to boost performance. This should not be used with --vsync drm/opengl/opengl-oml as they essentially does --sw-opti's job already, unless you wish to specify a lower refresh rate than the actual value.


Use EWMH _NET_ACTIVE_WINDOW to determine currently focused window, rather than listening to FocusIn/FocusOut event. Might have more accuracy, provided that the WM supports it.


Unredirect all windows if a full-screen opaque window is detected, to maximize performance for full-screen windows. Known to cause flickering when redirecting/unredirecting windows.

--unredir-if-possible-delay MILLISECONDS

Delay before unredirecting the window, in milliseconds. Defaults to 0.

--unredir-if-possible-exclude CONDITION

Conditions of windows that shouldn’t be considered full-screen for unredirecting screen.

--shadow-exclude CONDITION

Specify a list of conditions of windows that should have no shadow.

--fade-exclude CONDITION

Specify a list of conditions of windows that should not be faded.

--focus-exclude CONDITION

Specify a list of conditions of windows that should always be considered focused.


Use fixed inactive dim value, instead of adjusting according to window opacity.


Use WM_TRANSIENT_FOR to group windows, and consider windows in the same group focused at the same time.


Use WM_CLIENT_LEADER to group windows, and consider windows in the same group focused at the same time. WM_TRANSIENT_FOR has higher priority if --detect-transient is enabled, too.

--blur-method, --blur-size, --blur-deviation

Parameters for background blurring, see the BLUR section for more information.


Blur background of semi-transparent / ARGB windows. Bad in performance, with driver-dependent behavior. The name of the switch may change without prior notifications.


Blur background of windows when the window frame is not opaque. Implies --blur-background. Bad in performance, with driver-dependent behavior. The name may change.


Use fixed blur strength rather than adjusting according to window opacity.

--blur-kern MATRIX

Specify the blur convolution kernel, with the following format:


In other words, the matrix is formatted as a list of comma separated numbers. The first two numbers must be integers, which specify the width and height of the matrix. They must be odd numbers. Then, the following width * height - 1 numbers specifies the numbers in the matrix, row by row, excluding the center element.

The elements are finite floating point numbers. The decimal pointer has to be . (a period), scientific notation is not supported.

The element in the center will either be 1.0 or varying based on opacity, depending on whether you have --blur-background-fixed. Yet the automatic adjustment of blur factor may not work well with a custom blur kernel.

A 7x7 Gaussian blur kernel (sigma = 0.84089642) looks like:

--blur-kern '7,7,0.000003,0.000102,0.000849,0.001723,0.000849,0.000102,0.000003,0.000102,0.003494,0.029143,0.059106,0.029143,0.003494,0.000102,0.000849,0.029143,0.243117,0.493069,0.243117,0.029143,0.000849,0.001723,0.059106,0.493069,0.493069,0.059106,0.001723,0.000849,0.029143,0.243117,0.493069,0.243117,0.029143,0.000849,0.000102,0.003494,0.029143,0.059106,0.029143,0.003494,0.000102,0.000003,0.000102,0.000849,0.001723,0.000849,0.000102,0.000003'

May also be one of the predefined kernels: 3x3box (default), 5x5box, 7x7box, 3x3gaussian, 5x5gaussian, 7x7gaussian, 9x9gaussian, 11x11gaussian. All Gaussian kernels are generated with sigma = 0.84089642 . If you find yourself needing to generate custom blur kernels, you might want to try the new blur configuration supported by the experimental backends (See BLUR and --experimental-backends).

--blur-background-exclude CONDITION

Exclude conditions for background blur.

--resize-damage INTEGER

Resize damaged region by a specific number of pixels. A positive value enlarges it while a negative one shrinks it. If the value is positive, those additional pixels will not be actually painted to screen, only used in blur calculation, and such. (Due to technical limitations, with --use-damage, those pixels will still be incorrectly painted to screen.) Primarily used to fix the line corruption issues of blur, in which case you should use the blur radius value here (e.g. with a 3x3 kernel, you should use --resize-damage 1, with a 5x5 one you use --resize-damage 2, and so on). May or may not work with --glx-no-stencil. Shrinking doesn’t function correctly.

--invert-color-include CONDITION

Specify a list of conditions of windows that should be painted with inverted color. Resource-hogging, and is not well tested.

--opacity-rule OPACITY:'CONDITION'

Specify a list of opacity rules, in the format PERCENT:PATTERN, like 50:name *= "Firefox". picom-trans is recommended over this. Note we don’t make any guarantee about possible conflicts with other programs that set _NET_WM_WINDOW_OPACITY on frame or client windows.

--shadow-exclude-reg GEOMETRY

Specify a X geometry that describes the region in which shadow should not be painted in, such as a dock window region. Use --shadow-exclude-reg x10+0-0, for example, if the 10 pixels on the bottom of the screen should not have shadows painted on.


Crop shadow of a window fully on a particular Xinerama screen to the screen.

--backend BACKEND

Specify the backend to use: xrender, glx, or xr_glx_hybrid. xrender is the default one.

•xrender backend performs all rendering operations with X Render extension. It is what xcompmgr uses, and is generally a safe fallback when you encounter rendering artifacts or instability.

•glx (OpenGL) backend performs all rendering operations with OpenGL. It is more friendly to some VSync methods, and has significantly superior performance on color inversion (--invert-color-include) or blur (--blur-background). It requires proper OpenGL 2.0 support from your driver and hardware. You may wish to look at the GLX performance optimization options below. --xrender-sync-fence might be needed on some systems to avoid delay in changes of screen contents.

•xr_glx_hybrid backend renders the updated screen contents with X Render and presents it on the screen with GLX. It attempts to address the rendering issues some users encountered with GLX backend and enables the better VSync of GLX backends. --vsync-use-glfinish might fix some rendering issues with this backend.


GLX backend: Avoid using stencil buffer, useful if you don’t have a stencil buffer. Might cause incorrect opacity when rendering transparent content (but never practically happened) and may not work with --blur-background. My tests show a 15% performance boost. Recommended.


GLX backend: Avoid rebinding pixmap on window damage. Probably could improve performance on rapid window content changes, but is known to break things on some drivers (LLVMpipe, xf86-video-intel, etc.). Recommended if it works.


Disable the use of damage information. This cause the whole screen to be redrawn every time, instead of the part of the screen has actually changed. Potentially degrades the performance, but might fix some artifacts.


Use X Sync fence to sync clients' draw calls, to make sure all draw calls are finished before picom starts drawing. Needed on nvidia-drivers with GLX backend for some users.

--glx-fshader-win SHADER

GLX backend: Use specified GLSL fragment shader for rendering window contents. See compton-default-fshader-win.glsl and compton-fake-transparency-fshader-win.glsl in the source tree for examples.


Force all windows to be painted with blending. Useful if you have a --glx-fshader-win that could turn opaque pixels transparent.


Enable remote control via D-Bus. See the D-BUS API section below for more details.

--benchmark CYCLES

Benchmark mode. Repeatedly paint until reaching the specified cycles.

--benchmark-wid WINDOW_ID

Specify window ID to repaint in benchmark mode. If omitted or is 0, the whole screen is repainted.


Do not use EWMH to detect fullscreen windows. Reverts to checking if a window is fullscreen based only on its size and coordinates.


Dimming bright windows so their brightness doesn’t exceed this set value. Brightness of a window is estimated by averaging all pixels in the window, so this could comes with a performance hit. Setting this to 1.0 disables this behaviour. Requires --use-damage to be disabled. (default: 1.0)


Make transparent windows clip other windows like non-transparent windows do, instead of blending on top of them.


Some options accept a condition string to match certain windows. A condition string is formed by one or more conditions, joined by logical operators.

A condition with "exists" operator looks like this:


With equals operator it looks like:


With greater-than/less-than operators it looks like:


NEGATION (optional) is one or more exclamation marks;

TARGET is either a predefined target name, or the name of a window property to match. Supported predefined targets are id, x, y, x2 (x + widthb), y2, width, height, widthb (width + 2 * border_width), heightb, override_redirect, argb (whether the window has an ARGB visual), focused, wmwin (whether the window looks like a WM window, i.e. has no child window with WM_STATE and is not override-redirected), bounding_shaped, rounded_corners (requires --detect-rounded-corners), client (ID of client window), window_type (window type in string), leader (ID of window leader), name, class_g (= WM_CLASS[1]), class_i (= WM_CLASS[0]), and role.

CLIENT/FRAME is a single @ if the window attribute should be be looked up on client window, nothing if on frame window;

INDEX (optional) is the index number of the property to look up. For example, [2] means look at the third value in the property. Do not specify it for predefined targets.

FORMAT (optional) specifies the format of the property, 8, 16, or 32. On absence we use format X reports. Do not specify it for predefined or string targets.

TYPE is a single character representing the type of the property to match for: c for CARDINAL, a for ATOM, w for WINDOW, d for DRAWABLE, s for STRING (and any other string types, such as UTF8_STRING). Do not specify it for predefined targets.

OP QUALIFIER (optional), applicable only for equals operator, could be ? (ignore-case).

MATCH TYPE (optional), applicable only for equals operator, could be nothing (exact match), * (match anywhere), ^ (match from start), % (wildcard), or ~ (PCRE regular expression).

OPERATOR is one of = (equals), <, >, <=, =>, or nothing (exists). Exists operator checks whether a property exists on a window (but for predefined targets, exists means != 0 then).

PATTERN is either an integer or a string enclosed by single or double quotes. Python-3-style escape sequences and raw string are supported in the string format.

Supported logical operators are && (and) and || (or). && has higher precedence than ||, left-to-right associativity. Use parentheses to change precedence.


# If the window is focused
focused = 1
# If the window is not override-redirected
override_redirect = false
override_redirect != true
override_redirect != 1
# If the window is a menu
window_type *= "menu"
# If the window name contains "Firefox", ignore case
name *?= "Firefox"
_NET_WM_NAME@:s *?= "Firefox"
# If the window name ends with "Firefox"
name %= "*Firefox"
name ~= "Firefox$"
# If the window has a property _COMPTON_SHADOW with value 0, type CARDINAL,
# format 32, value 0, on its frame window
# If the third value of _NET_FRAME_EXTENTS is less than 20, or there's no
# _NET_FRAME_EXTENTS property on client window
# The pattern here will be parsed as "dd4"
name = "\x64\x64\o64"
# The pattern here will be parsed as "\x64\x64\x64"
name = r"\x64\x64\o64"


This is the old condition format we once used. Support of this format might be removed in the future.


TARGET is one of "n" (window name), "i" (window class instance), "g" (window general class), and "r" (window role).

TYPE is one of "e" (exact match), "a" (match anywhere), "s" (match from start), "w" (wildcard), and "p" (PCRE regular expressions, if compiled with the support).

FLAGS could be a series of flags. Currently the only defined flag is "i" (ignore case).

PATTERN is the actual pattern string.


picom could read from a configuration file if libconfig support is compiled in. If --config is not used, picom will seek for a configuration file in $XDG_CONFIG_HOME/picom.conf (~/.config/picom.conf, usually), then $XDG_CONFIG_HOME/picom/picom.conf, then $XDG_CONFIG_DIRS/picom.conf (often /etc/xdg/picom.conf), then $XDG_CONFIG_DIRS/picom/picom.conf.

picom uses general libconfig configuration file format. A sample configuration file is available as picom.sample.conf in the source tree. Most of commandline switches can be used as options in configuration file as well. For example, --vsync option documented above can be set in the configuration file using `vsync = `. Command line options will always overwrite the settings in the configuration file.

Window-type-specific settings are exposed only in configuration file and has the following format:


WINDOW_TYPE = { fade = BOOL; shadow = BOOL; opacity = FLOAT; focus = BOOL; full-shadow = BOOL; redir-ignore = BOOL; }; };

WINDOW_TYPE is one of the 15 window types defined in EWMH standard: "unknown", "desktop", "dock", "toolbar", "menu", "utility", "splash", "dialog", "normal", "dropdown_menu", "popup_menu", "tooltip", "notification", "combo", and "dnd".

Following per window-type options are available:

fade, shadow

Controls window-type-specific shadow and fade settings.


Controls default opacity of the window type.


Controls whether the window of this type is to be always considered focused. (By default, all window types except "normal" and "dialog" has this on.)


Controls whether shadow is drawn under the parts of the window that you normally won’t be able to see. Useful when the window has parts of it transparent, and you want shadows in those areas.


Controls whether this type of windows should cause screen to become redirected again after been unredirected. If you have --unredir-if-possible set, and doesn’t want certain window to cause unnecessary screen redirection, you can set this to true.


You can configure how the window background is blurred using a blur section in your configuration file. Here is an example:


method = "gaussian";
size = 10;
deviation = 5.0; };

Available options of the blur section are:


A string. Controls the blur method. Corresponds to the --blur-method command line option. Available choices are: none to disable blurring; gaussian for gaussian blur; box for box blur; kernel for convolution blur with a custom kernel. Note: gaussian and box blur methods are only supported by the experimental backends. (default: none)


An integer. The size of the blur kernel, required by gaussian and box blur methods. For the kernel method, the size is included in the kernel. Corresponds to the --blur-size command line option (default: 3).


A floating point number. The standard deviation for the gaussian blur method. Corresponds to the --blur-deviation command line option (default: 0.84089642).


A string. The kernel to use for the kernel blur method, specified in the same format as the --blur-kerns option. Corresponds to the --blur-kerns command line option.


•picom reinitializes itself upon receiving SIGUSR1.


It’s possible to control picom via D-Bus messages, by running picom with --dbus and send messages to com.github.chjj.compton.<DISPLAY>. <DISPLAY> is the display used by picom, with all non-alphanumeric characters transformed to underscores. For DISPLAY=:0.0 you should use com.github.chjj.compton._0_0, for example.

The D-Bus methods and signals are not yet stable, thus undocumented right now.


•Disable configuration file parsing:

$ picom --config /dev/null

•Run picom with client-side shadow and fading, disable shadow on dock windows and drag-and-drop windows:

$ picom -cCGf

•Same thing as above, plus making inactive windows 80% transparent, making frame 80% transparent, don’t fade on window open/close, enable software optimization, and fork to background:

$ picom -bcCGf -i 0.8 -e 0.8 --no-fading-openclose --sw-opti

•Draw white shadows:

$ picom -c --shadow-red 1 --shadow-green 1 --shadow-blue 1

•Avoid drawing shadows on wbar window:

$ picom -c --shadow-exclude 'class_g = "wbar"'

•Enable VSync with GLX backend:

$ picom --backend glx --vsync


Please submit bug reports to

Out dated information in this man page is considered a bug.




xcompmgr(1), picom-trans(1)

11/14/2020 picom v8.2