|Microsoft DirectX 9.0|
Axis coordinates can be returned as relative values—that is, the amount by which they have changed since the application last retrieved the device state or, in the case of buffered input, since the last item was put in the buffer.
Absolute axis coordinates are a running total of all the relative coordinates returned by the system since the device was acquired. In other words, they show the position of the axis in relation to a fixed point.
By default, mouse axes are reported as relative coordinates and joystick axes as absolute coordinates. You can change the coordinate system for a device by setting a property. For more information, see Device Properties.