compton 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.
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.
*--detect-rounded-corners*::
Try to detect windows with rounded corners and don't consider them shaped windows. The accuracy is not very high, unfortunately.
*--detect-client-opacity*::
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, compton will try detecting this with X RandR extension.
* 'opengl-swc': Try to VSync with 'SGI_swap_control' OpenGL extension. Only work on some drivers. Works only with GLX backend. Known to be most effective on many drivers. Does not actually control paint timing, only buffer swap is affected, so it doesn't have the effect of *--sw-opti* unlike other methods. Experimental.
Attempt to send painting request before VBlank and do XFlush() during VBlank. Reported to work pretty terribly. This switch may be lifted out at any moment.
Limit compton 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.
*--respect-prop-shadow*::
Respect '_COMPTON_SHADOW'. This a prototype-level feature, which you must not rely on.
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. *--paint-on-overlay* may make the flickering less obvious.
Use fixed inactive dim value, instead of adjusting according to window opacity.
*--detect-transient*::
Use 'WM_TRANSIENT_FOR' to group windows, and consider windows in the same group focused at the same time.
*--detect-client-leader*::
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-background*::
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-frame*::
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.
*--blur-background-fixed*::
Use fixed blur strength rather than adjusting according to window opacity.
Specify the blur convolution kernel, with the following format:
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----
WIDTH,HEIGHT,ELE1,ELE2,ELE3,ELE4,ELE5...
----
+
The element in the center must not be included, it will be forever 1.0 or changing 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 Guassian blur kernel (sigma = 0.84089642) looks like:
May also be one of the predefined kernels: `3x3box` (default), `5x5box`, `7x7box`, `3x3gaussian`, `5x5gaussian`, `7x7gaussian`, `9x9gaussian`, `11x11gaussian`. All Guassian kernels are generated with sigma = 0.84089642 . You may use the accompanied `compton-convgen.py` to generate blur kernels.
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 *--dbe* or *--glx-swap-method*, 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.
Specify a list of opacity rules, in the format `PERCENT:PATTERN`, like `50:name *= "Firefox"`. compton-trans is recommended over this. Note we do not distinguish 100% and unset, and 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.
Specify the backend to use: `xrender` or `glx`. GLX (OpenGL) backend generally has much superior performance as far as you have a graphic card/chip and driver.
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: Copy unmodified regions from front buffer instead of redrawing them all. My tests with nvidia-drivers show a 10% decrease in performance when the whole screen is modified, but a 20% increase when only 1/4 is. My tests on nouveau show terrible slowdown. Useful with `--glx-swap-method`, as well.
GLX backend: Use 'MESA_copy_sub_buffer' to do partial screen update. My tests on nouveau shows a 200% performance boost when only 1/4 of the screen is updated. May break VSync and is not available on some drivers. Overrides *--glx-copy-from-front*.
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). Recommended if it works.
GLX backend: GLX buffer swap method we assume. Could be `undefined` (0), `copy` (1), `exchange` (2), 3-6, or `buffer-age` (-1). `undefined` is the slowest and the safest, and the default value. `copy` is fastest, but may fail on some drivers, 2-6 are gradually slower but safer (6 is still faster than 0). Usually, double buffer means 2, triple buffer means 3. `buffer-age` means auto-detect using 'GLX_EXT_buffer_age', supported by some drivers. Useless with *--glx-use-copysubbuffermesa*. Partially breaks `--resize-damage`. Defaults to `undefined`.
Attempt to synchronize client applications' draw calls with `XSync()`, used on GLX backend to ensure up-to-date window content is painted.
*--xrender-sync-fence*::
Additionally use X Sync fence to sync clients' draw calls. Needed on nvidia-drivers with GLX backend for some users. May be disabled at compile time with `NO_XSYNC=1`.
'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), `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), `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.
Examples:
# If the window is focused
focused
focused = 1
# If the window is not override-redirected
!override_redirect
override_redirect = false
override_redirect != true
override_redirect != 1
# If the window is a menu
window_type *= "menu"
_NET_WM_WINDOW_TYPE@:a *= "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$"
# If the window has a property _COMPTON_SHADOW with value 0, type CARDINAL,
# format 32, value 0, on its frame window
_COMPTON_SHADOW:32c = 0
# If the third value of _NET_FRAME_EXTENTS is less than 20, or there's no
'TYPE' is one of "e" (exact match), "a" (match anywhere), "s" (match from start), "w" (wildcard), and "p" (PCRE regular expressions, if compiled with the support).
'FLAGS' could be a series of flags. Currently the only defined flag is "i" (ignore case).
compton could read from a configuration file if libconfig support is compiled in. If *--config* is not used, compton will seek for a configuration file in `$XDG_CONFIG_HOME/compton.conf` (`~/.config/compton.conf`, usually), then `~/.compton.conf`, then `compton.conf` under `$XDG_DATA_DIRS` (often `/etc/xdg/compton.conf`).
compton uses general libconfig configuration file format. A sample configuration file is available as `compton.sample.conf` in the source tree. Most commandline switches each could be replaced with an option in configuration file, thus documented above. Window-type-specific settings are exposed only in configuration file and has the following format:
'WINDOW_TYPE' is one of the 15 window types defined in EWMH standard: "unknown", "desktop", "dock", "toolbar", "menu", "utility", "splash", "dialog", "normal", "dropdown_menu", "popup_menu", "tooltip", "notify", "combo", and "dnd". "fade" and "shadow" controls window-type-specific shadow and fade settings. "opacity" controls default opacity of the window type. "focus" controls whether the window of this type is to be always considered focused. (By default, all window types except "normal" and "dialog" has this on.)
It's possible to control compton via D-Bus messages, by running compton with *--dbus* and send messages to `com.github.chjj.compton.<DISPLAY>`. `<DISPLAY>` is the display used by compton, with all non-alphanumeric characters transformed to underscores. For `DISPLAY=:0.0` you should use `com.github.chjj.compton._0_0`, for example.
The D-Bus methods and signals are not yet stable, thus undocumented right now.
* Run compton with client-side shadow and fading, disable shadow on dock windows and drag-and-drop windows:
+
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$ compton -cCGf
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* 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:
Please report any you find to <https://github.com/chjj/compton> .
AUTHORS
-------
xcompmgr, originally written by Keith Packard, with contributions from Matthew Allum, Eric Anholt, Dan Doel, Thomas Luebking, Matthew Hawn, Ely Levy, Phil Blundell, and Carl Worth. Compton by Christopher Jeffrey, based on Dana Jansens' original work, with contributions from Richard Grenville.
