In ubuntu core which is very thin ubuntu you can run UI application using linuxfb which is via raw framebuffer. It will be very slow. If your screen/UI is not updated frequently and just one screen is shown most of the time. You can do away with this.
./<yourFirstApplication> -platform linuxfb
./<yourSecondApplication> -platform linuxfb
Above works for my Qt application. But If you want good UI support you will need X11. You don’t need to reinvent the wheel by writing your own acceleration on top of linuxfb.
apt-get install xorg
With startx you can’t run applications on same display so :0 :1 is needed for each application
You use same terminal but different display application will run but display will be screwed whatever is changing the display that will be shown
Only part of the screen which is changed is updated weird
So run applications on different terminal and different display and then manage which terminal to show at any time.
startx ./yourFirstApplication — :0 vt7 &
startx ./yourSecondApplication — :1 vt8 &
startx ./yourThirdApplication — :2 vt9 &
Now whenever needed switch with ctl + alt + F1 for FirstApplication F2 for SecondApplication F3 for thirdApplication make sure to press two times for switch
Not working as expected : Still whatever is changing it is going there .. so expectation is eyeris-main and menu both will not be changing at the same time somehow we need to refresh the whole screen..
This is of-course not what you want. You can’t ask user to press the keys to switch between application. You want to automatically control this from your application. What to show at what time.
For me the applications were written in Qt so Qt already uses X11 to create and arrange window. I just need to make it run in single display with single instance of startx.
The solution is simple. Start one main application with startx and then run all application from that application. You can also use a lightweight program called xdotool to control which window to bring in front.
xdotool windowraise `xdotool search –class <application-name>`
Or you can go other way around by using some light weight desktop/window manager
apt-get install xdm
from xdm you can run without startx. This is all taken care of. You will also get a simple login screen with xdm.
apt-get install lightdm lightdm-gtk-greeter
There are other options also like
apt-get install nodm
apt-get install ubuntu-session
apt-get install xfce4 xfwm4 xfce4-panel xfce4-settings xfce4-session xfce4-terminal xfdesktop4 xfce4-taskmanager tango-icon-theme