JOYCALIBRATE

typedef struct joycalibrate_tag {
    UINT  wXbase;       // x-axis base calibration value.
    UINT  wXdelta;      // x-axis delta calibration value.
    UINT  wYbase;       // y-axis base calibration value.
    UINT  wYdelta;      // y-axis delta calibration value.
    UINT  wZbase;       // z-axis base calibration value.
    UINT  wZdelta;      // z-axis delta calibration value.
} JOYCALIBRATE;
 

Calibration values for the three axes of an absolute position device. Use the base and delta values returned in this structure to convert values retrieved from the device to values within the logical range specified by the driver.

The logical value returned for any axis is expressed by the following formula:

LogicalValue = Delta * DeviceValue + Base

The following formula is used to calculate delta values:

Delta = (LogicalMax - LogicalMin) / (DeviceMax - DeviceMin)

LogicalMax and LogicalMin represent the maximum and minimum logical coordinate values that the driver supports for the axis, as defined by the JOYCAPS structure. DeviceMax and DeviceMin represent the actual values returned by the device.

The following formula is used to calculate the base values:

Base = DeviceMin * Delta - LogicalMin

DeviceMin represents the minimum value returned by the device, Delta represents the multiplier of the device value, and LogicalMin represents the minimum value returned by the driver as defined by the JOYCAPS structure.

See Also

JDD_SETCALIBRATION, JOYCAPS