This effect rounds the corners of your windows and adds an outline around them without much affecting the performance of the KDE Plasma desktop (see #49 and #50).

This effect started as a fork of shapecorners with some additional contributions in Alex47's project, then optimized and reimplemented using shaders with influences from the invert effect.

This effect is maintained on KDE Plasma desktop versions 5.27 to 6.6+ in various Linux distros (See tests).

Tested configurations + Download links (.deb, .rpm)

Contributions:

• Compatibility of the effect with other effects like Wobbly windows
• Compatibility with KWin for Plasma versions 5.27 to 6.7+
• Compatibility with HDR in Plasma 6.0
• Compatibility with split KWin codebase dependency starting version 6.4 - see #383
• Optimize the effect to render once instead of 5 times - see #49
• Smooth animation when a window moves to an active state
• Reimplementation with shaders, including shadows at corners and three outlines
• Ability to disable the effect when windows get maximized or tiled
• Cleanups for the plugin logic, remove unneeded dependencies from CMakeLists.txt file - by alex1701c
• Separate outline color for active and inactive windows - by OrkenWhite
• Support for language translations - by VictorR2007 (See How to add more translations?)
• Squircle corner shape - by zxsleebu (See #503)

How to install using unofficial repositories

Copr package at matinlotfali/KDE-Rounded-Corners

sudo dnf copr enable matinlotfali/KDE-Rounded-Corners
sudo dnf install kwin-effect-roundcorners # or kwin-effect-roundcorners-x11 

AUR package by xiota

sudo pamac build kwin-effect-rounded-corners-git # or kwin-effect-rounded-corners-x11-git

NixOS package by flexagoon

nix-env -iA nixos.kde-rounded-corners

How to build from source code

You need to install development packages for your distribution first:

xbps-install git cmake make extra-cmake-modules gettext-devel kwin-devel kf6-kconfigwidgets-devel kf6-kcmutils-devel

Then clone the source code and compile it:

git clone https://github.com/matinlotfali/KDE-Rounded-Corners
cd KDE-Rounded-Corners
mkdir build
cd build
cmake ..
cmake --build . -j
sudo make install

cmake .. \
  -DCMAKE_INSTALL_PREFIX=~/kde/usr \
  -DKDE_INSTALL_PLUGINDIR=lib/qt6/plugins

sh ../tools/deploy-to-overlay.sh

How to load or unload the effect

To activate the effect, you can now log out and log back in, or run the command below inside the build directory:

sh ../tools/load.sh

To fully uninstall the effect, run the following commands inside the build directory:

sh ../tools/unload.sh
sudo make uninstall

How to auto-install after KWin update

After each KWin package update, the effect becomes incompatible. So it won't load without a rebuild.

As long as the effect is not part of the KWin yet (being discussed here), you can automate the re-installation by running the command below inside the build directory:

sh ../tools/install-autorun-test.sh

The command above adds a .desktop file inside the autorun directory which checks if the effect is still compatible, If it is incompatible, the script will automatically rebuild and reinstall the effect.

How to adjust its settings

You can change the corner radius, outlines, exclusions, and more in:

System Settings → Workspace Behavior → Desktop Effects → Rounded Corners

Extra Tips

How to add more languages to the translation

Translations are stored in po/<lang>/kcmcorners.po. One can copy from other languages and start editing it in a different subdirectory of po.

If the kcm.ui changes, a new language template .pot can be generated by running the script tools/generate-messages.sh.

How to add shadow to windows without decoration (like Steam)

You can add shadows for specific windows using the hack below.

1. In [ System settings ] → [ Window management ] → [ Window rules ] → [ Appearance & Fixes ]:

   Add [steam] and set [ No titlebar ] and frame to [ No ]

2. In [ System settings ] → [ Application Style ] → [ Window decoration ] → [ Breeze theme setting ] → [ Window specific overrides ]:

   Add [steam] and set [ Hide Window title bar ] to [ Yes ].

After that, the Steam window gets its shadows back.

How to add debug messages

When troubleshooting or reporting an issue, it might be useful to enable Debug logs during the build time using:

cmake .. -DCMAKE_BUILD_TYPE=Debug
cmake --build . -j

You may also need to add the default.debug=true rule in ~/.config/QtProject/qtlogging.ini. The example of the file content is:

[Rules]
*.debug=false
qt.qpa.xcb.xcberror.warning=false
default.debug=true

After the installation and loading the effect, debug messages would appear in journalctl:

journalctl -f | grep kwin

or have some colorful logs with

sh ../tools/show-kwin-logs.sh