The damage region has shadow drawn below it with use-damage = true

[sin-ack]

Platform

Gentoo 17.1 amd64

GPU, drivers, and screen setup

AMD Ryzen 5700U (Lucienne) / mesa 22.1.7 / xf86-video-amdgpu 22.0.0

glxinfo -B

name of display: :0
display: :0  screen: 0
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: AMD (0x1002)
    Device: AMD RENOIR (LLVM 14.0.6, DRM 3.48, 6.0.9-gentoo) (0x164c)
    Version: 22.1.7
    Accelerated: yes
    Video memory: 1024MB
    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: 453 MB, largest block: 453 MB
    VBO free aux. memory - total: 7332 MB, largest block: 7332 MB
    Texture free memory - total: 453 MB, largest block: 453 MB
    Texture free aux. memory - total: 7332 MB, largest block: 7332 MB
    Renderbuffer free memory - total: 453 MB, largest block: 453 MB
    Renderbuffer free aux. memory - total: 7332 MB, largest block: 7332 MB
Memory info (GL_NVX_gpu_memory_info):
    Dedicated video memory: 1024 MB
    Total available memory: 8433 MB
    Currently available dedicated video memory: 453 MB
OpenGL vendor string: AMD
OpenGL renderer string: AMD RENOIR (LLVM 14.0.6, DRM 3.48, 6.0.9-gentoo)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 22.1.7
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 22.1.7
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 22.1.7
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20

Environment

i3-gaps 4.20.1

picom version

v9.1

Diagnostics

Version: v9.1

Extensions:

• Shape: Yes
• XRandR: Yes
• Present: Present

Misc:

• Use Overlay: No
  (Another compositor is already running)
• Config file used: /home/agni/.config/picom.conf

Drivers (inaccurate):

AMDGPU, Radeon

Backend: glx

• Driver vendors:
• GLX: Mesa Project and SGI
• GL: AMD
• GL renderer: AMD RENOIR (LLVM 14.0.6, DRM 3.48, 6.0.9-gentoo)
• Accelerated: 1

Configuration:

Configuration file

#################################
#             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
shadow-radius = 7;

# 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
shadow-offset-x = -7;

# The top offset for shadows, in pixels. (defaults to -15)
# shadow-offset-y = -15
shadow-offset-y = -7;

# 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'",
  "_GTK_FRAME_EXTENTS@:c"
];

# Specify a list of conditions of windows that should have no shadow painted over, such as a dock window.
# clip-shadow-above = []

# 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 = ""

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


#################################
#           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 = 0.075;

# Opacity change between steps while fading out. (0.01 - 1.0, defaults to 0.03)
# fade-out-step = 0.03
fade-out-step = 0.075;

# 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 = 1.0;

# Let inactive opacity set by -i override the '_NET_WM_WINDOW_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 = 0.1

# Specify a list of conditions of windows that should never 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 = []


#################################
#           Corners             #
#################################

# Sets the radius of rounded window corners. When > 0, the compositor will
# round the corners of windows. Does not interact well with
# `transparent-clipping`.
corner-radius = 0

# Exclude conditions for rounded corners.
rounded-corners-exclude = [
  "window_type = 'dock'",
  "window_type = 'desktop'"
];


#################################
#     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 = true

# 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 = "7x7box";


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

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

# Enable remote control via D-Bus. See the man page for more details.
# dbus = true

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

# 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

# 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. This usually means windows from the same application
# will be considered focused or unfocused at the same time.
# 'WM_TRANSIENT_FOR' has higher priority if detect-transient is enabled, too.
#
# detect-client-leader = false

# 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 = true

# 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 = true

# 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.
# 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. Read the man page for a detailed explanation of the interface.
#
# window-shader-fg = "default"

# Use rules to set per-window shaders. Syntax is SHADER_PATH:PATTERN, similar
# to opacity-rule. SHADER_PATH can be "default". This overrides window-shader-fg.
#
# window-shader-fg-rule = [
#   "my_shader.frag:window_type != 'dock'"
# ]

# 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

# Specify a list of conditions of windows that should never have transparent
# clipping applied. Useful for screenshot tools, where you need to be able to
# see through transparent parts of the window.
#
# transparent-clipping-exclude = []

# 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 = "debug"
log-level = "warn";

# 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 = "/home/agni/.local/var/log/picom.log"

# 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.
#
#   clip-shadow-above:::
#     Controls whether shadows that would have been drawn above the window should
#     be clipped. Useful for dock windows that should have no shadow painted on top.
#
#   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 = 0.75; focus = true; full-shadow = false; };
  dock = { shadow = false; clip-shadow-above = true; opacity=0.8 }
  dnd = { shadow = false; }
  popup_menu = { opacity = 1.0; }
  dropdown_menu = { opacity = 1.0; }
};

Steps of reproduction

1. Enable shadow options and use-damage = true
2. Try to do something in i3 that generates damage.

I can reliably reproduce this by running xfce4-terminal and pressing the "window below" (default Super+K) button in i3 with the terminal being the only window in the workspace (which doesn't do anything but unfocuses and refocuses the window, which makes xfce4-terminal re-render only the current line, exhibiting the issue).

Expected behavior

No shadow artifacts, as shown with use-damage = false.

Current Behavior

Subtle shadow artifacts which aren't terrible but still annoying. Note the subtle dark lines above and below the line with the cursor.

OpenGL trace

picom-log.zip

[sin-ack]

I suppose the problem has to do with the xfce4-terminal itself being translucent and therefore displaying a shadow layer that's usually hidden by the opaque parts of regular windows.

[absolutelynothelix]

i can't see the difference between related to expected and current behavior pictures. are you talking about these things that are present on both pictures? (kind of white halo on black background)

[sin-ack]

I'm talking about the subtle black lines right above and below a line. If you closely look at the second image where the cursor is on "1", right above and below it are black lines. These lines happen anytime a damaged region is redrawn.

[absolutelynothelix]

does it happen with picom built from the latest commit in the next branch? i suspect that it's the same issue as #1088 that was fixed in #1095.