Reference Manual - 0.9.25
IDirectFBDisplayLayer   SetCursorAcceleration

Set cursor acceleration.

SetCursorAcceleration (
  IDirectFBDisplayLayer   * thiz,
  int   numerator,
  int   denominator,
  int   threshold
);

Sets the acceleration of cursor movements. The amount beyond the 'threshold' will be multiplied with the acceleration factor. The acceleration factor is 'numerator/denominator'.