In games like agar.io/slither.io/diep.io, the player is only shown a small section of the canvas. When they move, the player stays on the centre of the screen and instead the section of the canvas shown moves.
My question is: how did the developers of these games achieve this?
I thought it might have something to do with zooming in/out on the screen but then figured that can't be the case because you can manually zoom in/out.