Plugin based library to create window decorations.


KDecoration2 is a library to create window decorations. These window decorations can be used by for example an X11 based window manager which re-parents a Client window to a window decoration frame.

The library consists of two parts:

  • Decoration API for implementing a Decoration theme
  • Private API to implement the backend part (e.g. from Window Manager side)

Providing a Decoration

To provide a custom decoration one needs to create a plugin and provide an own implementation of KDecoration2::Decoration. For a framework to load and find the plugin it needs to be compiled with the proper json metadata. An example for such metadata (deco.json):

"KPlugin": {
"Id": "org.kde.myAweseomeDecoration",
"ServiceTypes": [
"X-KDE-ConfigModule": "kcm_name", /* comes with a configuration module */
"org.kde.kdecoration2": {
"blur": false, /* blur behind not needed */

To simplify one can use the KPluginFactory macro from the KCoreAddons framework:

#define K_PLUGIN_FACTORY_WITH_JSON(name, jsonFile, pluginRegistrations)

The plugin needs to get installed to ${KDE_INSTALL_PLUGINDIR}/org.kde.kdecoration2.

Configuring the Decoration

It is possible to provide a configuration module to tweak some aspects of the decoration. This is done by creating a plugin that provides such a configuration module.

The kcmoduleName specifies the name of the configuration module. It needs to be installed under ${KDE_INSTALL_PLUGINDIR}/org.kde.kdecoration2.kcm so that it can be looked up.