This routine sets the scale factor between the motion reported by the mouse and the size of one pixel. The larger the scale is, the slower the mouse cursor appears to move. The scale may be set to any non-zero integer.
Negative scales result in flipped axes.
Currently, there is no support for scale factors between 0 and 1 which would make the mouse appear faster than usual. If this routine is never called, scale s defaults to 1. The exact source of the referenced function as well as of the original documentation is unknown. Occasionally this might be wrong.