The JDD_GETPOS and JDD_GETPOSEX messages request device coordinate and button information. The driver fills in JOYINFO or JOYINFOEX structure, described in the Win32 SDK, and passes a pointer to it in the lParam1 parameter.
The coordinate values should be within the range the driver established when responding to the JDD_GETDEVCAPS message. When calculating the coordinate values, use the base- and delta-calibration values passed to the driver with the JDD_SETCALIBRATION message.