3.9.9. Qt graphics framework

Qt is a powerful C++ toolkit for writing cross-platform graphics applications, enabling a single code base to run predictably and perform well on Windows and embedded platforms,

Please refer https://www.qt.io/ for additional details on Qt.

The PSDK target file system includes the pre-built Qt libraries under /usr/lib and a rich set of Qt demo applications under /usr/share/examples.

3.9.9.1. Demos

Qt provides demos for the Wayland, Linux framebuffer (LINUXFB), and EGL Full Screen (EGLFS) backends. By default EGLFS will use the eglfs_kms backend.

$ /usr/share/examples/opengl/hellogles3/bin/hellogles3 -platform eglfs
$ /usr/share/examples/opengl/2dpainting/bin/2dpainting -platform eglfs
$ /usr/share/examples/opengl/openglwindow/bin/openglwindow -platform eglfs

For more information about the EGLFS platform abstraction and using Qt6 in embedded applications see:

https://doc.qt.io/qt-6/embedded-linux.html

3.9.9.2. Qt platform abstraction

The Qt6 within PSDK is prebuilt with Wayland enabled and therefore wayland-egl is the default Qt Platform Abstraction (QPA). Therefore all Qt applications should run on top of Weston. To run Qt application without Weston, the user can use -platform option to specify the desired QPA as linuxfb or eglfs.

Note

The fbdev interface used by default in the linuxfb platform is deprecated. The platform can use Dumb-Buffer allocations and required components of the new KMS interface while still using the same software rendering techniques. See QT_QPA_FB_DRM in the upstream documentation at: https://doc.qt.io/qt-6/embedded-linux.html#linuxfb

For example:

$ /usr/share/examples/opengl/2dpainting/bin/2dpainting -platform eglfs

3.9.9.3. Running Qt applications with the Weston In-Vehicle Infotainment shell

To run the Qt application with In-Vehicle Infotainment (IVI) shell, set the following environment variable, QT_WAYLAND_SHELL_INTEGRATION=ivi-shell.

$ export QT_WAYLAND_SHELL_INTEGRATION=ivi-shell