xrandr-keystone-helper
This programm helps finding the parameters for xrandr --transform. Helpfull for e.g. keystone-correction for projektors.
Transformed pictures with "xrandr --tranform" may (very likely) still have some issues espacially around the cursor. The result could sufficide for viewing movies or presenting slides.
Dependencies: python 3 numpy matplotlib
execute: $python xrandr-keystone-helper.py
adjust the red tetragon/quadrilateral and test the result until you find the right parameters. The string to use with xrandr --transform gets printed to the terminal.
To get the Testbutton working change eDP1 to the output you want to configure e.g. VGA1.