Xorg RandR
From EpixStudios
This simple method is used for displaying a presentation on an external projector. The laptop used has a native resolution of 1280x1024, however it is safe to assume most projectors will display 1024x768.
Query the possible devices that can be used on the current system
xrandr -q
Clone both displays to be the same (1024x768)
xrandr --output LVDS --mode 1024x768 --output VGA --mode 1024x768 --same-as LVDS
Afterwards, stop the external display and change laptop back to it's native resolution
xrandr --output LVDS --mode 1280x800 --output VGA --off
