xrandr: clone and scale

xrandr: clone and scale

私は定期的にノートパソコンを授業に使用し、プロジェクターに全画面を表示しています。プロジェクターの性能が上がるにつれて、プロジェクターの解像度が LCD 画面の解像度よりも高かったり、異なっていたりすることがよくあります (以前は 1024x768 のみを使用していました)。

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?

答え1

I figured out that the --scale-from option does what I need:

xrandr --output VGA1 --mode 1280x720 --output LVDS1 --primary --scale-from 1280x720 

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