Crop
Cropping keeps a selected rectangular region of an image and leaves the rest out of the presented result. It differs from scaling, which changes the size of the image, and rotation, which changes its orientation.
In BetterDisplay, a crop can select part of a display or window stream. Coordinates describe the region's origin, while width and height describe its size. Enlarging that region afterward does not recover image detail that was absent from the captured pixels.
The source remains intact. See Stream Display and Video Filters and Stream Transformations.