Displayplacer workaround: switch to unscaled modes by looking up mode number

resolutionSwitch.sh

# This is a workaround for https://github.com/jakehilborn/displayplacer/issues/35 and https://github.com/jakehilborn/displayplacer/issues/31
# Displayplacer ignores "scaling:off" and always enabling scaling unless you switch via mode number instead.
# It even turns scaling on for non-sense situations like when you're setting the resolution to your 
# display's physical resolution resulting in a subtle but serious performance hit.


function resolutionSwitch() {
  # check the output of `displayplacer list` and pass in everything after the "mode xx: " of the desired settings shown
  # if you want "scaling:off", just don't include scaling and pass in '$' at the end to match against the end
  # examples:
  #   $ resolutionSwitch "res:2304x1296 hz:60 color_depth:8$"
  #   $ resolutionSwitch "res:3008x1692 hz:60 color_depth:8 scaling:on"
  
  SID="2648EE53-5F1E-37A6-99FA-30FB0B2E49A9";     # replace with your monitor ID.  (or make it an argument)
  ## Alternatively, get the screen id based on the monitor's description
  ## SID=$(displayplacer list | grep -B2 "27 inch external screen" | grep Persistent | awk '{print $4}')

  # extract the displayplacer mode number for the desired settings
  DESIRED="$1"
  MODE_NUM=$(displayplacer list | sed -E "s/[[:blank:]]+(<-- current mode)?$//g" | sed -n -e "/$SID/,/Persistent screen/ p"  | grep -E "^  mode" | grep "$DESIRED" | cut -d ":" -f 1 | sed -E 's/^[[:blank:]]+mode[[:blank:]]//g')  # UGGLLLYYYYYY

  # check that a single mode was found
  if [ $(echo $MODE_NUM | wc -w) -ne 1 ]; then 
    echo "Did not find a unique mode number: '$MODE_NUM'...giving up"; 
    return;
  fi
  
  echo "Switching monitor '$SID' to mode '$MODE_NUM' which represents the settings '$DESIRED'";
  displayplacer "id:$SID mode:$MODE_NUM"
}