Hardware+OS setup for an Application - linux

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.

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.

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

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?

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.

Looking for a super tiny linux distro that's sole purpose is running an AIR application?

I'm looking for a really really small linux distribution or process of making my own that's sole purpose is to get an air application to launch full screen and stay there; Essentially I'm building a home kitchen computer that runs entirely as an AIR app.
I have looked into using windows xp; and windows xp embedded but they pose so many issues I figured I'd try modern linux.
I have also seen TinyCore Linux which looks interestingly small but not sure what issues that poses in regards to running AIR and "hardware" accelerated display. I've also thought about stripping down an Ubuntu installation but I'm sure somebody must have done this already; google is just failing me right now...
I'm also interested in running an "embedded" version of say android and running the air app on some arm-based hardware again; with just the AIR runtimes only - although this is less preferred as it's more complex.
I'm also hooking this up to a touch screen monitor (not yet arrived) so I'll need to hunt down or write some drivers for translating the touch events into something AIR can understand... (this was my main intention for using windows in that all the drivers will just work).
What I'm after
Minified Linux kernel with JUST the drivers for the box I need
X Display with accelerated graphics support (Doesn't have to be X if AIR can run on a frame buffer?)
Running a Full screen AIR application (simple enough)
Ability to write back to the filesystem (enough support for AIR)
SSH Access for remote control
Samba for updating the filesystem (easier to maintain the system)
Touch screen support (3M Ex III I think...)
Audio support
Don't need
Don't need any window manager or any other GUI tools unless required by AIR
Don't need any toolbars or file managers or anything; The AIR app is the "OS"
Don't need any package managers or repos
Don't need multi user or logging in; everything can just run as an unprivileged account
Don't need to
I don't mind hand crafting the filesystem and configs if that makes it easier; I'm mainly looking for a "filesystem" that is as tiny as possible that I can just plop my AIR app into and write some scripts to get it to start when the X server starts
Thanks,
Chris
Try an embedded Linux build system such as Buildroot. It can build an entire system from source, and be very lightweight. The basic system is less than 1 MB in size.
Ended up going with Tiny Core. Very tiny and quick to boot up. You can also write extensions for it and you don't have a persistent drive which allows you to just switch the thing off without worry that it's going to break something -- exactly what you need in a kitchen :-D.
My current plan is to:
Just set up a working version using Ubuntu as this is mostly supported by Adobe
Slowly strip it back and try and get as little things to start as possible on boot
Try building my own distro/package from source and selecting only the packages I need
Compile my own kernel with nearly everything turned off and just leave on the things I need

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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