What is the most basic window manager for ubuntu that can be used to display a single application

I've tried starting a full screen application without a window manager, using xinit, which works but instead of starting at the top left of the screen the application starts somewhere in the middle of my screen.

I've tried the same using a custom entry in /usr/share/xsessions and starting that from lightdm instead of the default ubuntu window manager, but that gives me the same result.

I've then added my application to the startup applications of the ubuntu window manager and that works properly... but I don't want to start the entire desktop

So I'm thinking perhaps a simple window manager will allow me to define that my application should start as soon as it is loaded and that as a result it will be displayed full screen and starting at the upper left corner of the screen.

So basically a Window Manager that will allow me to disable everything except my application. (And the background should be completely black by default so that the screen is black until my application has finished loading

Solution 1:

The ratpoison window manager is what you want.

1. Install ratpoison

   sudo apt-get install ratpoison
   

2. Create a user and have that user automatically log in.

3. Create a desktop file in /usr/share/xsessions/kiosk.desktop

   [Desktop Entry]
   Encoding=UTF-8
   Name=Browser Mode
   Comment=Kiosk desk Session
   Exec=/usr/share/xsessions/run_kiosk.sh
   Type=Application`
   

4. Create /usr/share/xsessions/run_kiosk.sh. Modify the following to get you started

   #!/bin/bash
   /usr/bin/ratpoison &
   
   TERMINAL=`who | awk '{print $2}'`
   
   if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
           eval 'dbus-launch --sh-syntax --exit-with-session'
   fi
   
   rm -Rf ~/.config/google-chrome
   dbus-launch /usr/bin/google-chrome --no-default-browser-check
   rm -Rf ~/.config/google-chrome
   
   kill `ps | grep dbus-launch | grep -v grep | awk '{print $1}'`
   

5. This resets Chrome on every launch. Use the default preferences in /opt/google/chrome/master_preferences to set up Chrome how you want it.

6. Set the default desktop as kiosk:

   sudo /usr/lib/lightdm/lightdm-set-defaults -s kiosk
   

Solution 2:

Have a look at the awesome window manager; it is a tiling windowmanager. It is extremely lightweight.

You can configure it to default to the full screen layout, a black background -- have a look at the wiki to get a feel for the configuration system, a minimal config in your case could contain something like the following:

Require dependencies:

require("awful")
require("awful.layout")
require("awful.util")
require("awful.tag")
require("screen")
require("freedesktop.utils")
require("freedesktop.desktop")

Limit the layouts to fullscreen with:

layouts =
{
    awful.layout.suit.max.fullscreen
}

Now define a tag for your application:

-- {{{ Tags
-- Define a tag table which will hold all screen tags.
tags = {
     names = {"your_app" },
     layout = {layouts[1]}
}
for s = 1, screen.count() do
   -- Each screen has its own tag table.
   tags[s] = awful.tag(tags.names, s, tags.layout)
end
-- }}}

To start your application add the following to the end of your configuration:

awful.util.spawn("/usr/bin/your_app --with --options")