With this option you can rotate the image as if using a trackball device. This means that when you left-click on a point and move the mouse, the geometric point tries to follow the mouse pointer. This can be imagined as a ball over the graphical window which is moved with the mouse.

The left mouse button can be pressed several times to engage and disengage the movement. To cancel this function, use escape (see Escape).

Rotate trackball

Trackball rotation