What I want to achieve is an elegant way to use my two screens on Lubuntu or Xubuntu. Being elegant means: 1) Working in the same extended-display mode as in
ubuntu-desktop (the common Unity Ubuntu) or Windows, or 2) Some other workaround that limit my LXDE or XFCE desktop on one screen and see something else (e.g. TTY or xterm) on the other screen.
The story comes below...
This is on an old DELL LATITUDE D600 laptop. It has a 1024x768 LCD and a VGA output.
I installed Xubuntu 12.04 LTS on this laptop and later changed to LXDE by installing
lubuntu-desktop and removing most of XFCE packages.
Now it has
unity-greeter) and LXDE.
When I attached a secondary screen to the laptop's VGA output, the two screens were working in mirror mode, whether I was in TTY,
unity-greeter, or LXDE desktop.
This behavior was different from my previous experience on some other laptop. On that other laptop, I have ever had Ubuntu 12.04 LTS, Ubuntu 13.10, and Ubuntu 14.04 LTS installed. TTY is usually displayed only on the external screen, and
unity-greeter should work in extended mode, where the login dialog is only displayed on one of the screens, leaving the other screen nothing but an Ubuntu icon as well as the greeter's wallpaper.
Let alone the different behavior here, I found that neither of XFCE or LXDE has built-in support for extended mode. Thus I was wondering if the behavior I observed above is laptop-dependent or actually distribution-dependent.
Having read lots of articles I found on Google, I got to know ARandR. However ARandR worked inelegantly, and also appeared different from dual-screen solutions in Ubuntu
ubuntu-desktop or Windows. When I use the
Print Screen key for screen-shot I got this:
Looks normal? Not at all. Since my external display was 1024x1280 (a vertically placed 1280x1024 LCD), the two screens didn't really form a rectangle shape when placed together. If I had two windows maximized on the two screens the screen-shot would look like this:
The upper right corner was not seen on any screen. This was why I said ARandR was inelegant and behaved differently from the extended mode in Ubuntu
ubuntu-desktop and that in Windows. If you've never seen the extended mode in
ubuntu-desktop or Windows I could post an image for them later.
The biggest problem was that, though I cannot move my cursor into the non-existing region of the ARandR desktop (e.g. the upper right corner in my screen-shots), the desktop was rendered on the entire rectangle region. This means, if the bottom line of my two screens are not of the same vertical coordinate (i.e. if my screens are not aligned to bottom), I will lose half of my task bar (depending on which screen is placed higher)!
And also, I found everything displayed extremely slowly on the vertical external screen. For example, when I open Firefox, first the frame of the window and the blank page is flashed up to down, then the contents of the new-tab page the same way... But things appeared OK on the laptop screen.
Story ends. Please refer to the first paragraph for my objectives. Achieving one of the two objectives will be good enough.
I've read this article: https://superuser.com/questions/562657/x-on-one-monitor-a-bare-tty-terminal-on-another-linux for using xterm on one display while running the desktop on the other. However,
xsetroot -display :0.1 -solid darkblue failed because it "cannot open display :0.1".
Screen 0: minimum 320 x 200, current 2048 x 1280, maximum 4096 x 4096 VGA-0 connected 1024x1280+0+0 left (normal left inverted right x axis y axis) 376mm x 301mm 1280x1024 60.0*+ 75.0 1152x864 75.0 1024x768 75.1 60.0 800x600 75.0 60.3 640x480 75.0 60.0 720x400 70.1 DVI-0 disconnected (normal left inverted right x axis y axis) LVDS connected 1024x768+1024+512 (normal left inverted right x axis y axis) 0mm x 0mm 1024x768 60.0*+ 800x600 59.9 848x480 59.7 720x480 59.7 640x480 59.4 S-video disconnected (normal left inverted right x axis y axis)
I don't really know how to identify my two screens using the numbers like