I regularly use my notebook for teaching, with the full screen shown on the projector. With projectors getting better, I often find the projectors resolution to be higher or different than the ones offered by my LCD screen (in the past I just used 1024x768).What I now would like to do is use the best resolution of the external display, while having the same content down-scaled on the notebook screen (without panning). Alternatively, if the resolution of the projector is smaller in one dimension, black bars would be ok on the LC display. I don't worry about aliasing artefacts on the LCD as long as the external projector uses the highest quality possible.For example, I recently had:LVDS1 connected 1280x800+0+0    1280x800       60.2*+   50.0     ...VGA1 connected 1280x720+0+0    1280x720       60.0*+   ...I tried:xrandr --output VGA1 --mode 1280x720 --output LVDS1 --mode 1280x800 but then the bottom of a full screen presentation was clipped on the projector. In this case, I would like a black bar or vertical rescaling on the laptop screen. How can I achieve that?I played with the scale option (can't reproduce this here without projector) but was unsuccessful.How can I achieve this behaviour?
xrandr: clone and scale
xrandr;display;resolution
I figured out that the --scale-from option does what I need:xrandr --output VGA1 --mode 1280x720 --output LVDS1 --primary --scale-from 1280x720 