3.6.7. 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/qt5/examples.

3.6.7.1. Demos

Demos using the Null Window System / KMS / DRM / EGLFS are provided with Qt. By default EGLFS will use the eglfs_kms backend.

$ /usr/share/qt5/examples/opengl/hellogles3/hellogles3 -platform eglfs
$ /usr/share/qt5/examples/opengl/2dpainting/2dpainting -platform eglfs
$ /usr/share/qt5/examples/opengl/paintedwindow/paintedwindow -platform eglfs

The default eglfs_kms configuration file for Qt5 is located at /etc/qt5/eglfs_kms_cfg.json.

For more information about Qt’s EGLFS and using Qt5 in embedded applications see:

https://doc.qt.io/qt-5/embedded-linux.html

3.6.7.2. QT QPA

The QT5 within PSDK is prebuilt with Wayland enabled and therefore wayland-egl is the default QPA. Hence all QT applications should be 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 linuxfb inteface is deprecated and requires switching the display into legacy fb mode.

For example:

$ /usr/share/qt5/examples/opengl/2dpainting/2dpainting -platform eglfs

3.6.7.3. Running QT Applications with the Weston IVI shell

To run the QT application with ivi-shell, set the QT_WAYLAND_SHELL_INTEGRATION environment variable to ivi-shell.

$ export QT_WAYLAND_SHELL_INTEGRATION=ivi-shell