--shadow-exclude-reg produces deprecation warning, but the suggested replacement can't do the same thing

[yump]

This issue is related to #4 and possibly #79.

I want to prevent shadows from being drawn on top of my taskbar. It doesn't look good:

When run like this:

> ./src/picom --config /dev/null --experimental-backends --backend glx --vsync -c --xinerama-shadow-crop --shadow-exclude-reg "x16+0+0"

picom produces the deprecation warning, "--shadow-exclude-reg is deprecated. You are likely better off using --shadow-exclude anyway".

There's also the -C option, which picom --help documents as "Avoid drawing shadows on dock/panel windows.", but that produces an error and says to use wintype instead.

I couldn't figure out how to format an argument to --shadow-exclude that would parse, so I switched to a config file:

picom.conf

#################################
#             Shadows           #
#################################


# 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.
#
# shadow = false
shadow = true;

# The blur radius for shadows, in pixels. (defaults to 12)
# shadow-radius = 12

# The opacity of shadows. (0.0 - 1.0, defaults to 0.75)
# shadow-opacity = .75

# The left offset for shadows, in pixels. (defaults to -15)
# shadow-offset-x = -15

# The top offset for shadows, in pixels. (defaults to -15)
# shadow-offset-y = -15

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

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

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

# Hex string color value of shadow (#000000 - #FFFFFF, defaults to #000000). This option will override options set shadow-(red/green/blue)
# shadow-color = "#000000"

# Specify a list of conditions of windows that should have no shadow.
#
# examples:
#   shadow-exclude = "n:e:Notification";
#
# shadow-exclude = []
shadow-exclude = [
  "name = 'Notification'",
  "class_g = 'Conky'",
  "class_g ?= 'Notify-osd'",
  "class_g = 'Cairo-clock'",
  "class_g = 'awesome'",
  "_GTK_FRAME_EXTENTS@:c"
];

# 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.
#
# shadow-exclude-reg = ""
#shadow-exclude-reg = "x16+0+0"

# Crop shadow of a window fully on a particular Xinerama screen to the screen.
# xinerama-shadow-crop = false
xinerama-shadow-crop = true


#################################
#           Fading              #
#################################


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

# Opacity change between steps while fading in. (0.01 - 1.0, defaults to 0.028)
# fade-in-step = 0.028
#fade-in-step = 0.03;

# Opacity change between steps while fading out. (0.01 - 1.0, defaults to 0.03)
# fade-out-step = 0.03
#fade-out-step = 0.03;

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

# Specify a list of conditions of windows that should not be faded.
# fade-exclude = []

# Do not fade on window open/close.
# no-fading-openclose = false

# Do not fade destroyed ARGB windows with WM frame. Workaround of bugs in Openbox, Fluxbox, etc.
# no-fading-destroyed-argb = false


#################################
#   Transparency / Opacity      #
#################################


# Opacity of inactive windows. (0.1 - 1.0, defaults to 1.0)
# inactive-opacity = 1
#inactive-opacity = 0.8;

# Opacity of window titlebars and borders. (0.1 - 1.0, disabled by default)
# frame-opacity = 1.0
#frame-opacity = 0.7;

# Let inactive opacity set by -i override the '_NET_WM_OPACITY' values of windows.
# inactive-opacity-override = true
inactive-opacity-override = false;

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

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

# Specify a list of conditions of windows that should always be considered focused.
# focus-exclude = []
focus-exclude = [ "class_g = 'Cairo-clock'" ];

# Use fixed inactive dim value, instead of adjusting according to window opacity.
# inactive-dim-fixed = 1.0

# 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.
# example:
#    opacity-rule = [ "80:class_g = 'URxvt'" ];
#
# opacity-rule = []


#################################
#     Background-Blurring       #
#################################


# Parameters for background blurring, see the *BLUR* section for more information.
# blur-method =
# blur-size = 12
#
# blur-deviation = false
#
# blur-strength = 5

# 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 = false

# 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-frame = false


# Use fixed blur strength rather than adjusting according to window opacity.
# blur-background-fixed = false


# Specify the blur convolution kernel, with the following format:
# example:
#   blur-kern = "5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1";
#
# blur-kern = ""
blur-kern = "3x3box";


# Exclude conditions for background blur.
# blur-background-exclude = []
blur-background-exclude = [
  "window_type = 'dock'",
  "window_type = 'desktop'",
  "_GTK_FRAME_EXTENTS@:c"
];

#################################
#       General Settings        #
#################################

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

# Specify the backend to use: `xrender`, `glx`, or `xr_glx_hybrid`.
# `xrender` is the default one.
#
# backend = "glx"
backend = "glx";

# Enable/disable VSync.
# vsync = false
vsync = true;

# Enable remote control via D-Bus. See the *D-BUS API* section below for more details.
# dbus = false

# Try to detect WM windows (a non-override-redirect window with no
# child that has 'WM_STATE') and mark them as active.
#
# mark-wmwin-focused = false
mark-wmwin-focused = true;

# Mark override-redirect windows that doesn't have a child window with 'WM_STATE' focused.
# mark-ovredir-focused = false
#mark-ovredir-focused = true;

# Try to detect windows with rounded corners and don't consider them
# shaped windows. The accuracy is not very high, unfortunately.
#
# detect-rounded-corners = false
#detect-rounded-corners = true;

# Detect '_NET_WM_OPACITY' on client windows, useful for window managers
# not passing '_NET_WM_OPACITY' of client windows to frame windows.
#
# detect-client-opacity = false
detect-client-opacity = true;

# Specify refresh rate of the screen. If not specified or 0, picom will
# try detecting this with X RandR extension.
#
# refresh-rate = 60
refresh-rate = 0;

# 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.
#
# use-ewmh-active-win = false

# 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 = false
unredir-if-possible = false

# Delay before unredirecting the window, in milliseconds. Defaults to 0.
# unredir-if-possible-delay = 0

# Conditions of windows that shouldn't be considered full-screen for unredirecting screen.
# unredir-if-possible-exclude = []

# Use 'WM_TRANSIENT_FOR' to group windows, and consider windows
# in the same group focused at the same time.
#
# detect-transient = false
detect-transient = true;

# 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.
#
# detect-client-leader = false
detect-client-leader = true;

# 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.
#
# resize-damage = 1

# Specify a list of conditions of windows that should be painted with inverted color.
# Resource-hogging, and is not well tested.
#
# invert-color-include = []

# 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-no-stencil = false

# 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.
#
# glx-no-rebind-pixmap = false

# Disable the use of damage information.
# This cause the whole screen to be redrawn everytime, instead of the part of the screen
# has actually changed. Potentially degrades the performance, but might fix some artifacts.
# The opposing option is use-damage
#
# no-use-damage = false
use-damage = true

# 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.
#
# xrender-sync-fence = false

# 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.
#
# glx-fshader-win = ""

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

# Do not use EWMH to detect fullscreen windows.
# Reverts to checking if a window is fullscreen based only on its size and coordinates.
#
# no-ewmh-fullscreen = false

# 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)
#
# max-brightness = 1.0

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

# 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.
#
# log-level = "warn"
log-level = "info";

# 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.
#
# log-file = "/path/to/your/log/file"

# Show all X errors (for debugging)
# show-all-xerrors = false

# Write process ID to a file.
# write-pid-path = "/path/to/your/log/file"

# Window type settings
#
# '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.
#
#   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.)
#
#   full-shadow:::
#     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.
#
#   redir-ignore:::
#     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`.
#
wintypes:
{
  tooltip = { fade = true; shadow = true; opacity = 0.9; focus = true; full-shadow = false; };
  dock = { shadow = false; }
  dnd = { shadow = false; }
  popup_menu = { opacity = 0.9; }
  dropdown_menu = { opacity = 0.9; }
};

As you can see, I'm trying to use both wintypes and shadow-exclude to say "no shadows for the taskbar".

But they both seem to do the same thing, which is to stop the taskbar from casting a shadow. What I want, is to keep it from receiving any shadows.

In the config file, shadow-exclude-reg does work, and does not produce a deprecation warning. But there are a couple problems:

1. The deprecation warning for the command line argument makes me worry that it might be removed in the future.

2. shadow-exclude-reg can only mask off one rectangular region, and if my monitors weren't the same resolution and side-by-side, that wouldn't be enough.

(Incidentally, the comment in the sample config file says x10+0+0 will mask 10 rows at the bottom of the screen, but it actually masks the top. The man page, which uses x10+0-0, is correct.)

Platform

Fedora Workstation 32, amd64

GPU, drivers, and screen setup

AMD RX 580, amdgpu, Xorg 1.20.8, two monitors configured side-by-side with xrandr.

> glxinfo -B

name of display: :0
display: :0  screen: 0
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: X.Org (0x1002)
    Device: Radeon RX 580 Series (POLARIS10, DRM 3.37.0, 5.7.16-200.fc32.x86_64, LLVM 10.0.1) (0x67df)
    Version: 20.1.7
    Accelerated: yes
    Video memory: 4096MB
    Unified memory: no
    Preferred profile: core (0x1)
    Max core profile version: 4.6
    Max compat profile version: 4.6
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2
Memory info (GL_ATI_meminfo):
    VBO free memory - total: 3509 MB, largest block: 3509 MB
    VBO free aux. memory - total: 3945 MB, largest block: 3945 MB
    Texture free memory - total: 3509 MB, largest block: 3509 MB
    Texture free aux. memory - total: 3945 MB, largest block: 3945 MB
    Renderbuffer free memory - total: 3509 MB, largest block: 3509 MB
    Renderbuffer free aux. memory - total: 3945 MB, largest block: 3945 MB
Memory info (GL_NVX_gpu_memory_info):
    Dedicated video memory: 4096 MB
    Total available memory: 8192 MB
    Currently available dedicated video memory: 3509 MB
OpenGL vendor string: X.Org
OpenGL renderer string: Radeon RX 580 Series (POLARIS10, DRM 3.37.0, 5.7.16-200.fc32.x86_64, LLVM 10.0.1)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 20.1.7
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile

OpenGL version string: 4.6 (Compatibility Profile) Mesa 20.1.7
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile

OpenGL ES profile version string: OpenGL ES 3.2 Mesa 20.1.7
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20

Environment

Awesome WM

picom version

**Version:** vgit-9bb21

### Extensions:

* Shape: Yes
* XRandR: Yes
* Present: Present

### Misc:

* Use Overlay: Yes* Config file used: None

### Drivers (inaccurate):

AMDGPU, Radeon

(note: I had to run meson --reconfigure and rebuild before picom --version would give the correct output, because the commit id was cached from several pulls ago.)

[ivanmilov]

I use this rule in the config file to not drop the shadow on my bottom bar:
shadow-exclude-reg = "x25+0-0"

shadow-exclude-reg can only mask off one rectangular region, and if my monitors weren't the same resolution and side-by-side, that wouldn't be enough.

This could be fixed by converting 'shadow-exclude-reg' to the array.
As a temp solution, I hardcoded another subtraction in render.c:

			// Mask out the region we don't want shadow on
			if (pixman_region32_not_empty(&ps->shadow_exclude_reg))
				pixman_region32_subtract(&reg_tmp, &reg_tmp,
				                         &ps->shadow_exclude_reg);

			{ //  my hardcode :)
				region_t reg;
				pixman_region32_init(&reg);
				pixman_region32_clear(&reg);
				pixman_region32_union_rect(&reg, &reg, (int)1920, (int)0,
				                           (uint)40, (uint)1080);
				pixman_region32_subtract(&reg_tmp, &reg_tmp, &reg);
				pixman_region32_fini(&reg);
			}

@yump you can modify it for your setup.
Adding multiple regions to exclude could be a good feature. @yshui

[tryone144]

Exempting taskbars from receiving shadows can now be achieved by the clip-shadow-above wintype option for dock (see example config).