To manipulate screen size with scale option
If craphic card does not allow big enough resolution, one way to manipulate screen is to scale screen size. At first need to know display port
xrandr | grep connected
Also screen size is good to know
xdpyinfo | grep -B2 resolution
If wanting a ”bigger resolution”, place your display output on the output section like VGA1
(in this computer is LVDS).
xrandr --output LVDS --scale 1.25x1.25
If wanting a ”smaller resolution” set a different value like –scale 0.75×0.75
xrandr --output LVDS --scale 0.75x0.75
To restore original size
xrandr --output LVDS --scale 1x1
Of course you can add the command to the startup applications or script