Viewport

[deezy]

/viewport [x y h w]

The first number determines where you want the viewing area to start from the left side of the screen measured in pixels.
The second number is where it'll start from the top of the screen.
The third number is the height of the viewing area.
And last is the width of the viewing area.

If your native resolution on your monitor is 1920x1080 and wanted the viewing area to take up the full screen you would use:
/viewport 0 0 1920 1080

You might want to try:
/viewport 240 0 1440 1080