Toggle between widescreen and standard screen aspect ratio

Instructions on how to create bash aliases to quickly toggle between widescreen and standardscreen aspect ratio. The motivation for this toggle is for when you are sharing a widescreen monitor to someone with a standard screen monitor. To avoid disconnecting cables and keeping your current display setup, this will allow you to quickly change the aspect ratio so that the standard screen user can properly read text on your screen.

The following steps were tested with a Dell U3415W monitor and macOS Monterey.

Prereq

• If you are on an M1 mac, install Rosetta: https://support.apple.com/en-us/HT211861
• Configure monitor to adjust aspect ratio automatically
  • Menu > Display > Auto Resize
• Install displayplacer

  brew tap jakehilborn/jakehilborn && brew install displayplacer
  

Steps

• Open System Preferences > Displays > Display Settings...
• Select the widescreen monitor and the option Default for Display
• Run displayplacer list and store the result as the alias display-wide

  alias display-wide='displayplacer "id:E4903C2D-EA27-4BA0-BF75-DCC5DB90E9B6 res:3440x1440 hz:60 color_depth:8 scaling:off origin:(0,0) degree:0" "id:37D8832A-2D66-02CA-B9F7-8F30A301B230 res:1728x1117 hz:120 color_depth:8 scaling:on origin:(-1728,323) degree:0" "id:0A0593DB-8A8E-4429-9961-8A960ED1EDC9 res:1920x1080 hz:60 color_depth:8 scaling:off origin:(3440,360) degree:0"'
  

• Select the widescreen monitor and the option Scaled > 2560 x 1440
• Run displayplacer list and store the result as the alias display-standard

  alias display-standard='displayplacer "id:E4903C2D-EA27-4BA0-BF75-DCC5DB90E9B6 res:1920x1080 hz:60 color_depth:8 scaling:off origin:(0,0) degree:0" "id:37D8832A-2D66-02CA-B9F7-8F30A301B230 res:1728x1117 hz:120 color_depth:8 scaling:on origin:(-1728,-37) degree:0" "id:0A0593DB-8A8E-4429-9961-8A960ED1EDC9 res:1920x1080 hz:60 color_depth:8 scaling:off origin:(1920,0) degree:0"'