1XGetDeviceMotionEvents(3) X FUNCTIONS XGetDeviceMotionEvents(3)
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6 XGetDeviceMotionEvents, XDeviceTimeCoord - get device motion history
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9 XDeviceTimeCoord *XGetDeviceMotionEvents(Display *display, XDevice
10 *device, Time start, Time stop, int *nevents_return, int
11 *mode_return, int *axis_count_return);
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14 display Specifies the connection to the X server.
15 device Specifies the device whose motion history is to be queried.
17 start
19 stop Specify the time interval in which the events are returned
20 from the motion history buffer. You can pass a timestamp
21 or CurrentTime.
22 nevents_return
24 Returns the number of events from the motion history buf‐
25 fer.
26 mode_return Returns the mode of the device (Absolute or Relative).
28 axis_count_return
30 Returns the count of axes being reported.
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33 The server may retain the recent history of the device motion and do so
34 to a finer granularity than is reported by DeviceMotionNotify events.
35 The XGetDeviceMotionEvents request makes this history available.
36 The XGetDeviceMotionEvents request returns all events in the motion
38 history buffer that fall between the specified start and stop times,
39 inclusive. If the start time is later than the stop time or if the
40 start time is in the future, no events are returned. If the stop time
41 is in the future, it is equivalent to specifying CurrentTime.
42 The mode indicates whether the device is reporting absolute positional
44 data (mode=Absolute) or relative motion data (mode=Relative). Some
45 devices allow their mode to be changed via the XSetDeviceMode request.
46 These constants are defined in the file XI.h. The axis_count returns
47 the number of axes or valuators being reported by the device.
48 XGetDeviceMotionEvents can generate a BadDevice, or BadMatch error.
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52 The XDeviceTimeCoord structure contains:
53 typedef struct {
55 Time time;
56 int *data;
57 } XDeviceTimeCoord;
58 The time member is set to the time, in milliseconds. The data member
60 is a pointer to an array of integers. These integers are set to the
61 values of each valuator or axis reported by the device. There is one
62 element in the array per axis of motion reported by the device. The
63 value of the array elements depends on the mode of the device. If the
64 mode is Absolute, the values are the raw values generated by the
65 device. These may be scaled by client programs using the maximum val‐
66 ues that the device can generate. The maximum value for each axis of
67 the device is reported in the max_val field of the XAxisInfo returned
68 by the XListInputDevices request. If the mode is Relative, the data
69 values are the relative values generated by the device.
70 You should use XFreeDeviceMotionEvents to free the data returned by
72 this request.
73 Errors returned by this request: BadDevice, BadMatch.
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77 BadDevice An invalid device was specified. The specified device does
78 not exist or has not been opened by this client via XOpen‐
79 InputDevice. This error may also occur if the specified
80 device is the X keyboard or X pointer device.
81 BadMatch This error may occur if an XGetDeviceMotionEvents request
83 is made specifying a device that has no valuators and
84 reports no axes of motion.
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87 Programming with Xlib
88X Version 11 libXi 1.1.1 XGetDeviceMotionEvents(3)