How can I mirror one of the screens in a 3-monitor setup?

Is it possible to have 2 extended monitors and get the third being a mirror of one of the two extended?

I'm pretty sure it's not possible through the interface but it may be possible through commands or configuration file.

If it's seems weird for you, here is my setup :

• 2 monitors, pretty classic working with dual monitor
• 1 big TV that I use as a projector to show things off to people (on meetings for example)

Solution 1:

You need to look at xrandr command

May be something like:

xrandr --output SCREEN1 --output SCREEN2 --output SCREEN3 --same-as SCREEN2

where SCREEN3 mirrors SCREEN2.

Replace SCREEN1, SCREEN2, SCREEN3 with the appropriate name that you get with the xrandr command (without any option).

For example, LDVS1, HDMI1, VGA1, etc ...

Solution 2:

If you have an NVIDIA graphics card, you can do this rather easily in NVIDIA X Server Settings.

Under X Server Display Configuration, select a monitor and for its position, select "Same as" and then the name of your monitor, for example "ViewSonic VX2552 Series".

Fortunately for me, my monitor and TV are the same resolution!