CCilot XA and CCpilot XS
Product revision: 0.12
Software guide
2018-03-19
www.crosscontrol.com
25
7.5.
Frame buffer graphics
The graphics framework uses the Linux frame buffer for graphics operations. It’s fast and efficient,
and has vast standard support in the Linux user space world. For instance, Qt has a plugin that
enables the Qt libraries to be built with direct frame buffer drawing possibilities. For Qt
applications the impact for that means that it simply needs to be started with a specific flag, -qws,
and built with the correct development libraries.
Other application software that uses the frame buffer directly can also be used. However, there is
no default windowing system on the frame buffer, so careful consideration there needs to be taken
when using this kind of applications.
Multiple instances of Qt applications work fine, and can be seen as a windowing system as well,
since that’s a characteristic of the Qt QWS system. However, only one Qt application should act as
the GUI server, i.e. use the –qws flag when starting. Make sure that the graphical applications
adhere to that requirement for proper usage of Qt applications on the frame buffer.
7.6.
Default start-up application
As mentioned in 3.4 Default start-up application, CCpilot versions have a GUI application that is
started by default. CrossCore XS versions still has the actual GUI application installed and
executable, but it’s not started since the system can detect that the display is missing. The default
application looks like:
A user can and should replace or simply edit the default startup application script, i.e. the init script
found at
/opt/etc/init.d/StartupGui
. This init script is automatically run when entering run level 3
(during boot) or run level 6 (during shutdown/reboot).
Note: This script is part of the rc script solution mention in section 7.1.4. Make sure the correct
script behavior is met; otherwise it can break the XA device startup procedure.
An example of the default startup script is given here for illustration purposes:
