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XGetDeviceMotionEvents(3)                        X FUNCTIONS                       XGetDeviceMotionEvents(3)



NAME
       XGetDeviceMotionEvents, XDeviceTimeCoord - get device motion history

SYNTAX
       XDeviceTimeCoord  *XGetDeviceMotionEvents(Display  *display,  XDevice *device, Time start, Time stop,
              int *nevents_return, int *mode_return, int *axis_count_return);

ARGUMENTS
       display     Specifies the connection to the X server.

       device      Specifies the device whose motion history is to be queried.

       start
       stop        Specify the time interval in which the  events  are  returned  from  the  motion  history
                   buffer.  You can pass a timestamp or CurrentTime.

       nevents_return
                   Returns the number of events from the motion history buffer.

       mode_return Returns the mode of the device (Absolute or Relative).

       axis_count_return
                   Returns the count of axes being reported.

DESCRIPTION
       The  server  may retain the recent history of the device motion and do so to a finer granularity than
       is reported by DeviceMotionNotify events.  The  XGetDeviceMotionEvents  request  makes  this  history
       available.

       The  XGetDeviceMotionEvents request returns all events in the motion history buffer that fall between
       the specified start and stop times, inclusive.  If the start time is later than the stop time  or  if
       the  start  time  is in the future, no events are returned.  If the stop time is in the future, it is
       equivalent to specifying CurrentTime.

       The mode indicates whether the device is reporting absolute positional data (mode=Absolute) or  rela-tive relative
       tive motion data (mode=Relative).  Some devices allow their mode to be changed via the XSetDeviceMode
       request.  These constants are defined in the file XI.h.  The axis_count returns the number of axes or
       valuators being reported by the device.

       XGetDeviceMotionEvents can generate a BadDevice, or BadMatch error.

STRUCTURES
       The XDeviceTimeCoord structure contains:

       typedef struct {
            Time time;
            int *data;
       } XDeviceTimeCoord;

       The  time  member  is  set to the time, in milliseconds.  The data member is a pointer to an array of
       integers.  These integers are set to the values of each valuator or  axis  reported  by  the  device.
       There  is one element in the array per axis of motion reported by the device.  The value of the array
       elements depends on the mode of the device.  If the mode is Absolute, the values are the  raw  values
       generated  by  the  device.  These may be scaled by client programs using the maximum values that the
       device can generate.  The maximum value for each axis of the device is reported in the max_val  field
       of the XAxisInfo returned by the XListInputDevices request.  If the mode is Relative, the data values
       are the relative values generated by the device.

       You should use XFreeDeviceMotionEvents to free the data returned by this request.

       Errors returned by this request: BadDevice, BadMatch.

DIAGNOSTICS
       BadDevice   An invalid device was specified.  The specified device does not exist  or  has  not  been
                   opened  by  this client via XOpenInputDevice.  This error may also occur if the specified
                   device is the X keyboard or X pointer device.

       BadMatch    This error may occur if an XGetDeviceMotionEvents request is  made  specifying  a  device
                   that has no valuators and reports no axes of motion.

SEE ALSO
       Programming with Xlib



X Version 11                                     libXi 1.2.1                       XGetDeviceMotionEvents(3)