This isn’t a proper blog post or walk-through, its just a quick brain dump so I can document the future process for myself, lest I do this to myself.

Aim is to resize my screen to that the edges of the image aren’t cut off by my TV’s bezel, below is some real quick and rough documentation of how I did it This will require a lot of trial and error

xrandr -q #To query curent info (--query also works)
xrandr -s <num> #To change/test current options (use to figure out your wanted screensize) or
xrandr --output <connected monitor name> --mode <name of mode> # same as above line, substitue required info with info from the query statement
# Example usage of above two lines
xrandr -s 2 #To select the second option or it can be done like so
xrandr --output HDMI-3 --mode 1280x720

So after a bit of testing I landed on 1200x768 being the correct size for my screen, with nothing being cut off. To add this new size/mode into xrandr we are gonna want to rely on a tool to give us the correct info, for this example we will use gtf

gtf 1200 768 60 # gtf <width> <height> <refresh rate>
  
  # 1200x768 @ 60.00 Hz (GTF) hsync: 47.70 kHz; pclk: 74.79 MHz
  Modeline "1200x768_60.00"  74.79  1200 1256 1384 1568  768 769 772 795  -HSync +Vsync

We are going to want to copy everything after the word Modeline and we will use that info to add a new mode into xrandr

xrandr --newmode "1200x768_60.00"  74.79  1200 1256 1384 1568  768 769 772 795  -HSync +Vsync
xrandr --addmode HDMI-3 "1200x768_60.00"
xrandr --output HDMI-3 --mode 1200x768_60.00

Line by line, here is what the above does:

• line 1 creates a new mode with the info from gtf
• line 2 makes it available for our wanted output, which in this case is HDMI-3, again reference xrandr –query to see the info corresponding to your screen name
• line 3 switches the mode on HDMI-3 to our new mode

Now if we want to scale it to a resolution of 1920x1080 (For example) we can do it by so:

1920/1200 = 1.6
1080/768 = 1.40625

Replace the appropriate values with your own, in both above maths and in the following commands.

Now to scale it we can do:

xrandr --output HDMI-3 --mode 1200x768_60.00 --panning 1920x1080 --scale 1.6x1.40625

If you want to restore/revert to the original resolution you can do:

xrandr --output HDMI-3 --mode 1200x768_60.00 --panning 1200x768 --scale 1x1

This last tidbit of info came from @mmacm with their answer on a unix stack exchange question.

This info took a few hours to find/figure out, so consolidating the info into one page seems useful to my future self and others, even if its a bit rough around the edges.

:)