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X11R7.4 - man page for xgetdevicemotionevents (x11r4 section 3)

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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 granu-
       larity 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=Abso-
       lute)  or  relative  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)
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