Rotate drawing tablet 180 degrees on linux while using multiple or single monitor(s)

huion_rotate.sh

bash -c 'name="HUION Huion Tablet Pen (0)";a=($(xinput list-props "$name"| grep -Po "Coordinate\sTransformation\sMatrix(.*?):\s\K.*"|tr -d ","));a[2]=$(echo ${a[0]}+${a[2]}|bc);a[5]=$(echo ${a[4]}+${a[5]}|bc);a[0]=$(echo ${a[0]}*-1|bc);a[4]=$(echo ${a[4]}*-1|bc);xinput set-prop "$name" "Coordinate Transformation Matrix" ${a[*]}'

for script to work you need to install bc
remember to put your own device name instead HUION Huion Tablet Pen Pen (0) (you can get it by running xinput).
This is a one liner so you can put it as a keyboard shortcut from settings