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When giving presentations, I use the html/css/js-based showoff. It has a presenter mode which shows the notes and the progress in a good way for me. It seems like the idea is that somehow a second browser gets the changes I do in this mode, but that does not work.

Therefore I thought of putting just the part of the presenter mode which displays the current slide (this is a 1024x768 area) on another device, namely the beamer display.

As X has such a vast tooling box, I figured this could be possible. The presentation has been given with mirrored displays, which went good enough. What remains is the curiosity if it would have been possible:

Can I display part of a window on the second device?

I use xmonad as window manager normally. If this is supported by another window manager, I could switch just for presentations.


I am more interested in the way this could be achieved by X11 means (or related tools) than just having the presenation run fine. That's just the incident that created my interest in such a solution.


I am still looking for a pure X11-solution, but the problem at hand is of course solved.

share|improve this question
See answer involving xrandr here: unix.stackexchange.com/questions/97005/… – Jason C Oct 25 '13 at 2:49
If this were an answer, I would mark it as the right one. Thanks :) – kronn Oct 29 '13 at 21:45
up vote 1 down vote accepted

I don't know a thing about showoff, but I did use dzslides in a similar way. Things to check are:

  • Does you window manager support multiple displays? (E.g. after xrandr --output VGA1 --right-of LVDS1, does it handle the "other one"?) XMonad should,, i3 provides good multihead support, too.
  • Your presenter console should control the other window in normal presentation mode. What happens when you open both modes in separate windows? I.e. when showoff says

    Your ShowOff presentation is now starting up.
    To view it plainly, visit [ #{url} ]
    To run it from presenter view, go to: [ #{url}/presenter ]

    try opening both URLs in two windows.

  • If, as I hope it does, the presenter view window controls the plain view one, just move the plain view window to the other monitor (this depends on how your WM handles multiple monitors). If it doesn't, you could consider filing an issue...

This should be easier than X11 hackery.

share|improve this answer
I have no problems with multiple displays, thanks to xmonad. Opening both modes in separate windows does not lead to them updating at the same time. At least not in my testing. – kronn Dec 14 '12 at 11:02
Also, I am more interested in the X11 hackery as the presentation itself is over. – kronn Dec 14 '12 at 11:04
In current showoff, the presenter-url opens a second window which reflects the state you see in the presenter-mode. This does not satisfy my curiosity, but solve my problem. :) – kronn Jul 19 '13 at 16:52

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