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Green Island

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Green Island provides a full blown Wayland compositor for QtQuick as well as pluggable hardware abstraction, extensions, tools and a Qt-style API for Wayland clients.

The name comes from Kure Atoll, Hawaii.

It is primarily developed for the Hawaii desktop environment, however it can be used by any desktop environment that wish to implement its compositor by using QML or for shells deeply integrated with the compositor in the same process.


Green Island includes:

  • A QtWaylandCompositor API copy
  • Compositor extensions for xdg-shell, screenshots, screencast, applicaion manager, task manager
  • Support for Plasma 5
  • XWayland support
  • Multiple screen support
  • Qt-style API for udev, logind and libinput
  • Launcher for various hardware configurations
  • QPA plugin
  • Pluggable hardware abstraction with support for:
    • X11
    • Wayland
    • DRM/KMS
    • All Raspberry Pi boards
    • Mali
    • Vivante
  • Compositor to run your UX
  • Minimal desktop compositor and shell
  • Qt-style API for Wayland clients

A QtWaylandCompositor API copy is available here and it's built as one of the Green Island libraries until the upstream code will be stable, feature complete and available on some distributions (Fedora and ArchLinux are the main targets here because they are pretty up to date). Relying on an always changing API that is not available on distros made the development harder in the past, to overcome this issue it has been decided to ship a copy here until the requirements listed above are not met. Once the time will come we'll remove the copy here and just link to the official library.

The server-side API extends QtWaylandCompositor with additional features needed by any real world Wayland compositor.

Green Island offers multiple screen support and it also implements specific protocols such as xdg-shell, gtk-shell and those for Plasma 5.

Additional Wayland protocols for shells built with Green Island are provided, such as greenisland_applications and greenisland_windows for task managers.

Also include a launcher that executes the compositor on different hardware, a screencaster protocol and command line application, plus a minimal Wayland compositor and shell written with QML.


Licensed under either of the following licenses:

  • GNU Lesser General Public License version 3.0
  • GNU General Public License version 2.0 or (at your option) version 3.0 or any later version approved by the KDE Free Qt Foundation.


Compiler requirements:

Qt >= 5.6.0 with at least the following modules is required:

The following modules and their dependencies are required:

Optional dependencies:

  • Weston >= 1.5.0 to nest Green Island into Weston with the fullscreen shell protocol, useful only if your device is not yet supported by Green Island but works with Weston.

If you enable DRM/KMS device integration you also need:

If you enable Broadcom VideoCore device integration you also need:

If you enable Vivante device integration you also need:

If you enable XWayland support you also need:

Build and installation

Building Green Island is a piece of cake.

Assuming you are in the source directory, just create a build directory and run cmake:

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=/opt/hawaii ..

To do a debug build the last command can be:


To do a release build instead it can be:

cmake -DCMAKE_INSTALL_PREFIX=/opt/hawaii -DCMAKE_BUILD_TYPE=Release ..

If not passed, the CMAKE_INSTALL_PREFIX parameter defaults to /usr/local. You have to specify a path that fits your needs, /opt/hawaii is just an example.

The CMAKE_BUILD_TYPE parameter allows the following values:

  • Debug: debug build
  • Release: release build
  • RelWithDebInfo: release build with debugging information

System-wide installation

Those who want to perform a system-wide installation, such as package maintainers, should pass different arguments to cmake:

mkdir build
cd build

Feel free to choose whatever CMAKE_BUILD_TYPE value you desire.

Configuration arguments


    Enabled by default. Pass -DENABLE_EGLDEVICEINTEGRATION_KMS:BOOL=OFF to cmake if you don't want to build the DRM/KMS device integration.

    Please note that this way you won't be able to run Green Island on DRM/KMS devices.


    Enabled by default. Pass -DENABLE_EGLDEVICEINTEGRATION_BRCM:BOOL=OFF to cmake in order to disable the Broadcom VideoCore device integration.

    You will need Broadcom VideoCore proprietary libraries.

    Notable examples of devices powered by a Broadcom GPU are Raspberry Pi and Raspberry Pi 2.


    Disabled by default. Pass -DENABLE_EGLDEVICEINTEGRATION_MALI:BOOL=ON to cmake in order to enable Mali device integration.

    You will need Mali proprietary libraries.


    Disabled by default. Pass -DENABLE_EGLDEVICEINTEGRATION_VIV:BOOL=ON to cmake in order to enable Vivante device integration.

    You will need Freescale proprietary Vivante GPU libraries.


    Enabled by default. Pass -DENABLE_XWAYLAND:BOOL=OFF to cmake if you don't want to build the XWayland plugin.

    If disabled, compatibility with old X11-only applications will not work.


    Disabled by default. Pass -DENABLE_ONLY_EGLDEVICEINTEGRATION:BOOL=ON to cmake in order to build and install device integration plugins.

    This option is meant for packagers. The best way to package Green Island for multiple devices is to ship device integration plugins with separate packages.


It's really easy, it's just a matter of typing:

make install

from the build directory.


Environment variables

Qt Platform Abstraction

Green Island leverages the Qt Platform Abstraction available since Qt 5 to run the compositor without another windowing system such as Wayland or X11. The "greenisland" QPA plugin has support for different hardware through EGL device integration plugins.

There are a number of environment variables that can influence the QPA plugin:

  • GREENISLAND_QPA_DEBUG: When set, some debugging information is printed on the debug output such as the EGL configuration being used while creating a new context.

  • GREENISLAND_QPA_WIDTH and GREENISLAND_QPA_HEIGHT: Screen width and height in pixels (screen resolution). This variable is used only on platforms where detecting it from the framebuffer device /dev/fb0 fails.

  • GREENISLAND_QPA_DEPTH: Overrides the color depth for the screen. On platforms where the framebuffer device /dev/fb0 is not available or the query is not successful, the default value of 32 is used. Setting this variable can override any such default. Please note that this affects only the color depth reported by the screen and it is irrelevant to EGL configurations and the color depth used for OpenGL rendering.

  • GREENISLAND_QPA_PHYSICAL_WIDTH and GREENISLAND_QPA_PHYSICAL_HEIGHT: Physical screen width and height in millimiters. On platforms where the /dev/fb0 framebuffer device is not available, or the query is not successful, the values are calculated based on a default DPI of 100. These variables can be used to override such default values.

  • GREENISLAND_QPA_CONFIG: Path to the QPA plugin configuration, used only by the kms EGL device integration. By default the path is "~/.config/greenisland/platform.json".

  • GREENISLAND_QPA_SWAPINTERVAL: By default a swap interval of 1 will be requested. This enables synchronizing to the display vertical refresh. Passing 0 will disable blocking on swap, resulting in running as fast as it's possible without any synchronization.

  • GREENISLAND_QPA_FORCEVSYNC: When set, FBIO_WAITFORVSYNC is requested on the framebuffer device.

  • GREENISLAND_QPA_FORCE888: When set, the red, green and blue color channels are ignored whenever creating a new context, window or offscreen surface. Instead a configuration of 8 bits per channel is requested. Useful on devices where configurations with less than 24 or 32 bits per channel are chosen by default but are not suitable, for example due to banding effects. This variable moves the control of color channels from the compositor to a setting that allows a more flexible per-device configuration.

  • GREENISLAND_QPA_ENABLE_TERMINAL_KEYBOARD: By default terminal keyboard is disabled on compositor startup by setting tty's keyboard mode to K_OFF preventing keystrokes from going to the terminal.

  • GREENISLAND_QPA_INTEGRATION: EGL device integration to be loaded at compositor startup. By default the QPA plugin autodetects which plugin needs to be loaded, if for some reason autodetection fails a specific plugin can be set with this variable. Set the EGL device integration plugin file name without path and extension (for example "kms" for the DRM/KMS integration, "brcm" for Broadcom etc...).

  • GREENISLAND_QPA_SHOW_CURSOR: By default the mouse cursor is not drawed because a compositor is expected to render the Wayland cursor surface, set this variable to 1 if you want to draw the Green Island cursor.

Logging categories

Qt 5.2 introduced logging categories and Hawaii takes advantage of them to make debugging easier.

Please refer to the Qt documentation to learn how to enable them.

Available categories

  • Server-side:

    • greenisland.compositor: Core compositor classes
    • greenisland.screenbackend.native: Native screen backend
    • greenisland.screenbackend.fake: Fake screen backend
    • greenisland.outputmanagement: The greenisland_outputmanagement protocol
    • greenisland.protocols.gtkshell: gtk_shell
    • greenisland.protocols.gtkshell.trace: gtk_shell trace
    • greenisland.protocols.recorder: greenisland_recorder
    • greenisland.protocols.screenshooter: greenisland_screenshooter
    • greenisland.protocols.taskmanager: greenisland_windows
  • Client-side:

    • greenisland.client.registry: Registry
    • greenisland.client.shmpool: Shared memory pool
    • greenisland.client.cursortheme: Cursor theme
    • greenisland.client.fullscreenshell: Full screen shell
  • Platform:

    • greenisland.qpa.deviceintegration: Device integration
    • greenisland.qpa.input: Input management on device integration plugins
    • greenisland.qpa.logind: Logind integration
    • greenisland.qpa.udev: udev integration
  • EGL Device Integrations:

    • greenisland.qpa.wayland: Wayland EGL device integration
  • Plugins:

    • org_kde_plasma_shell protocol
    • greenisland.plugins.plasma.effects: org_kde_plasma_effects protocol
    • greenisland.xwayland: xwayland
    • greenisland.xwayland.trace: xwayland protocol trace