110 lines
3.8 KiB
Plaintext
110 lines
3.8 KiB
Plaintext
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XGETDEVICEMOTIONEVENTS(libmansuffix)
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====================================
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NAME
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----
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XGetDeviceMotionEvents, XDeviceTimeCoord - get device motion
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history
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SYNOPSIS
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--------
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#include <X11/extensions/XInput.h>
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XDeviceTimeCoord *XGetDeviceMotionEvents( Display *display,
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XDevice *device,
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Time start,
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Time stop,
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int *nevents_return,
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int *mode_return,
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int *axis_count_return);
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display
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Specifies the connection to the X server.
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device
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Specifies the device whose motion history is to be
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queried.
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start, stop
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Specify the time interval in which the events are
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returned from the motionhistory buffer.You can pass a
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timestamp or CurrentTime.
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nevents_return
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Returns the number of events from the motion history
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buffer.
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mode_return
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Returns the mode of the device (Absolute or Relative).
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axis_count_return
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Returns the count of axes being reported.
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DESCRIPTION
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-----------
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The server may retain the recent history of the device motion
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and do so to a finer granularity than is reported by
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DeviceMotionNotify events. The XGetDeviceMotionEvents request
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makes this history available.
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The XGetDeviceMotionEvents request returns all events in the
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motion history buffer that fall between the specified start and
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stop times, inclusive. If the start time is later than the stop
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time or if the start time is in the future, no events are
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returned. If the stop time is in the future, it is equivalent
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to specifying CurrentTime.
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The mode indicates whether the device is reporting absolute
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positional data (mode = Absolute ) or relative motion data
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(mode = Relative ). Some devices allow their mode to be changed
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via the XSetDeviceMode request. These constants are defined in
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the file XI.h. The axis_count returns the number of axes or
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valuators being reported by the device.
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XGetDeviceMotionEvents can generate a BadDevice, or BadMatch
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error.
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Structures
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The XDeviceTimeCoord structure contains:
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typedef struct {
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Time time;
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int *data;
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} XDeviceTimeCoord;
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The time member is set to the time, in milliseconds. The data
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member is a pointer to an array of integers. These integers are
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set to the values of each valuator or axis reported by the
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device. There is one element in the array per axis of motion
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reported by the device. The value of the array elements depends
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on the mode of the device. If the mode is Absolute, the values
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are the raw values generated by the device. These may be scaled
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by client programs using the maximum values that the device can
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generate. The maximum value for each axis of the device is
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reported in the max_val field of the XAxisInfo returned by the
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XListInputDevices request. If the mode is Relative, the data
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values are the relative values generated by the device.
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You should use XFreeDeviceMotionEvents to free the data
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returned by this request.
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Errors returned by this request: BadDevice, BadMatch.
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DIAGNOSTICS
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-----------
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BadDevice
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An invalid device was specified. The specified device
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does not exist or has not been opened by this client via
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XOpenInputDevice. This error may also occur if the
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specified device is the X keyboard or X pointer device.
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BadMatch
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This error may occur if an XGetDeviceMotionEvents
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request is made specifying a device that has no
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valuators and reports no axes of motion.
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