Making a GUI in Linux without booting the OS's GUI - linux

Sorry if I'm using wrong terminology here.
I'd like to make an appliance for users that's running from a Raspberry Pi. When it's booted, I'd like users to see my own GUI that I'll design (hopefully in PyQT but I'm not sure about that yet.)
The thing I don't know how to do: I don't want the users to see the Linux operating system on the screen at all. I don't want them to see the desktop and launch my app. I want my app to be automatically launched on startup. I want it to be the only thing accessible and visible to the users. i.e. it should be full-screen and a user wouldn't be able to exit it or interact with the OS in any way.
How can I do that?

Related

How to add splash screen on custom linux(specially raspberry pi)

I currently have a project so basically what i want is to create an embedded linux in raspberry pi. What i want to achieve is to boot my custom made linux in my raspberry pi. I'm currently using Buildroot for that.
Here are the things what i want to happen:
Create a splash screen(How to implement this? What are the files on linux needed to edit. )
Override login prompt after booting(I want to use my own prompt which is i already created using python. What i want here is after booting my python app will be the first one to display)
Display my python application after booting.
WHAT files/configurations i need to know.
HOW to implement this. Process or a work flow.
Just like osmc or kido but i want to build my own also from scratch. Any help will be appreciated.
There are multiple components involved in splash screen. One is what you can display when u-boot starts and then the kernel takes over. You can get some information here and here. Both require re compilation of u-boot and Linux kernel. May be even some more additional steps depending on system. Also note this transition is not going to be smooth, between the logo displayed by u-boot and then the kernel.
On desktops, this is generally taken care of by software like Plymouth.
From what I understand, you want your python application to auto start after booting. Have a look at writing a systemd service for that as described here.

Hardware+OS setup for an Application

I want to make a system which would get input from USB barcode scanner, validate it on remote server and display an answer (text and images).
I would use JavaFX or in-browser JS web application to grab scanner input somehow.
I'm planning to run this application on Raspberry Pi or plain PC.
Is there a way (or a special linux distribution) to ensure that system always loads the same way and starts JavaFX app or opens particular web page in browser?
e.g. no login page, NO update or other popups are shown.
Any other ideas? Thanks
...
Found an interesting solution here, where JavaFX GUI app is started from command line, without X-Server(linux graphical interface) at all.
I have recently done something similar, and it's not too hard. Obviously working on the Pi, you will want to use something like Linux and having limited hardware will mean that you should be minimising what you are running. Due to this, I would recomend that you run a light weight distro. Something like arch (which is what I used) allows you to build only what you want from the ground up without the need to find and compile everything like you do for LFS or Gentoo.
As for booting, the following two wikis will give you the details of starting the Gui without manual login:
https://wiki.archlinux.org/index.php/Automatic_login_to_virtual_console
https://wiki.archlinux.org/index.php/Start_X_at_Login
After that, it is simply a matter of putting the command to launch your program in .xinitrc.

Start web app on Raspberry Pi

I'm currently putting together a project where my application will have a web based frontend and will be running on a microcontroller. In order to provide a friendly UI I would like my app UI to startup without showing any Unix screens, such as splash screen, login and BIOS. This is supposed to behave as an embedded system.
Since my app is browser dependent, I presume I'm going to need my Linux graphical desktop environment running in the background but the less I have running the better.
What is the best OS Rasberry PI for this purpose and how do I make it behave as an embedded system?
Thanks in advance.
regards,
ForeignerBR
Your solution could likely be the following:
Raspbian is the most supported operating system on the Pi at this time and most Linux Debian applications are on there. For speed Arch is the best (but has no GUI as standard).
You could then get it to login & start up into X11 automatically and then set it to launch up the web browser.
I would recommend chromium as you can start it up into a full screen Kiosk mode via the command line. So at boot it would show the command line and possibly the start of a GUI but once booted up should just display the browser.
Hope This Helps -
Ryan Walmmsley

How to simultaneously run multiple window managers (esp. xmonad) for VNC

I'll start with a little background. A small project of mine has been to try to use my Android tablet as an external monitor for my laptop using a VNC client (vnc4server). There are two main options for doing this that I have seen. The simplest is to use xrandr and widen the screen, creating a section just for the tablet. However, this can cause some graphics issues if I understand correctly, although it has the benefit of permitting windows to cross displays. The other option is to run a separate desktop session for the VNC server.
I have chosen to go the route of a second desktop as the session can live and die without significantly affecting my main session and can in theory be tailored specifically to the tablet. A little tool called x2vnc allows me to connect to the VNC server in a similar manner to the more popular Synergy and use it like a n external monitor. I also have the nice little benefit of being able to easily and cleanly switch from landscape to portrait using xrandr.
This brings me to my current issue. So far, I have only been able to reliably use plain x-windows. Although this is entirely functional, I would prefer something more complete. Although xstartup examples have been posted for a variety of window managers, none of these seem to run properly. I suspect all of these are for headless systems. Gnome/Unity are each unforgivably slow and seem to conflict with my existing session. I also feel that these are a little too cluttered for my ten inch tablet. On the other hand, Xmonad simply crashes as soon as I try to open a second window in addition to not updating the graphics properly.
I would like to know anything that will lead me in the direction of a better stable desktop environment. This includes configuration tips and alternate window managers.
I am currently running Ubuntu 12.04 with gnome-xmonad (recently Unity). My xstartup is plain x-window-manager. I have tried any readily available examples for gnome and xmonad that I have been able to find.

How to start a gtk application after booting up without logging in?

I have got a gtk application. I want it to start automatically when I boot up the system, such that instead of getting usual login screen, my application greets the user.
My application is a sort of cash dispensing application. So user should not even see the login screen of linux. Whenever machine in boot up, after loading services and all that, my application should appear on the screen. One should not have to put any password or login in anyway to start that application.
Now so far I have tried the following but all in vain.
I put the command in my /etc/rc.local file
/home/EXE/cashier
Then rebooted machine in run level 5. But nothing happens. I get the usual login screen. Other programs that do not involve any gui or gtk, they are automatically started in this manner but not the gtk application.
Then I put
xint /home/EXE/cahier
and later
xint /home/EXE/./cashier
But they too didn't work. When I looked into details, I found out that "An Xserver is already running on screen 0, cannot open other server" or something like that.
Then I tried booting into run level 3, this time it worked.
xint /home/EXE/.cachier
But in run level 3, the font and icon sizes are smaller. Moreover some windows do not cover the whole screen.
Now I will really appreciate a way to run my application in run level 5, without showing login screen automatically.
Regards
Edit
Currently, the application is running on fedora core 2
This is more a question about linux distribution startup than it is about Gtk applications. The specifics are going to depend on your distribution, but the essence is:
Disable the gdm facility, which is normally responsible for spawning your X server.
Run xinit (not "xint") to start the server manually. This takes a client as its argument. It may work to run your Gtk application directly (it needs to be smart enough to position and size itself instead of relying on a window manager), but more likely you will want to pick a window manager to run it in. The easiest way to do this is via script that you pass to xinit.

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