NAME
XSendEvent, XDisplayMotionBufferSize, XGetMotionEvents, XTimeCoord - send events
and pointer motion history structure
SYNTAX
Status
XSendEvent(Display * display, Window w, Bool propagate,
long event_mask, XEvent *event_send);
unsigned long
XDisplayMotionBufferSize(Display * display);
XTimeCoord
*XGetMotionEvents(Display * display, Window w, Time
start, Time stop, int *nevents_return);
ARGUMENTS
- display
- Specifies the connection to the X server.
- event_mask
- Specifies the event mask.
- event_send
- Specifies the event that is to be sent.
- nevents_return
- Returns the number of events from the motion history
buffer.
- propagate
- Specifies a Boolean value.
- start
-
- stop
- Specify the time interval in which the events are returned
from the motion history buffer. You can pass a timestamp or
CurrentTime. PointerWindow, or InputFocus.
- w
- Specifies the window the window the event is to be sent
to,.
DESCRIPTION
The
XSendEvent function identifies the destination window, determines
which clients should receive the specified events, and ignores any active
grabs. This function requires you to pass an event mask. For a discussion of
the valid event mask names, see section 10.3. This function uses the w
argument to identify the destination window as follows:
- •
- If w is PointerWindow, the destination window is the
window that contains the pointer.
- •
- If w is InputFocus and if the focus window contains
the pointer, the destination window is the window that contains the
pointer; otherwise, the destination window is the focus window.
To determine which clients should receive the specified events,
XSendEvent uses the propagate argument as follows:
- •
- If event_mask is the empty set, the event is sent to the
client that created the destination window. If that client no longer
exists, no event is sent.
- •
- If propagate is False, the event is sent to every
client selecting on destination any of the event types in the event_mask
argument.
- •
- If propagate is True and no clients have selected on
destination any of the event types in event-mask, the destination is
replaced with the closest ancestor of destination for which some client
has selected a type in event-mask and for which no intervening window has
that type in its do-not-propagate-mask. If no such window exists or if the
window is an ancestor of the focus window and InputFocus was
originally specified as the destination, the event is not sent to any
clients. Otherwise, the event is reported to every client selecting on the
final destination any of the types specified in event_mask.
The event in the
XEvent structure must be one of the core events or one
of the events defined by an extension (or a
BadValue error results) so
that the X server can correctly byte-swap the contents as necessary. The
contents of the event are otherwise unaltered and unchecked by the X server
except to force send_event to
True in the forwarded event and to set
the serial number in the event correctly; therefore these fields and the
display field are ignored by
XSendEvent.
XSendEvent returns zero if the conversion to wire protocol format failed
and returns nonzero otherwise.
XSendEvent can generate
BadValue
and
BadWindow errors.
The server may retain the recent history of the pointer motion and do so to a
finer granularity than is reported by
MotionNotify events. The
XGetMotionEvents function makes this history available.
The
XGetMotionEvents function returns all events in the motion history
buffer that fall between the specified start and stop times, inclusive, and
that have coordinates that lie within the specified window (including its
borders) at its present placement. If the server does not support motion
history, if the start time is later than the stop time, or if the start time
is in the future, no events are returned;
XGetMotionEvents returns
NULL. If the stop time is in the future, it is equivalent to specifying
CurrentTime.
XGetMotionEvents can generate a
BadWindow
error.
STRUCTURES
The
XTimeCoord structure contains:
typedef struct {
Time time;
short x, y;
} XTimeCoord;
The time member is set to the time, in milliseconds. The x and y members are set
to the coordinates of the pointer and are reported relative to the origin of
the specified window.
DIAGNOSTICS
- BadValue
- Some numeric value falls outside the range of values
accepted by the request. Unless a specific range is specified for an
argument, the full range defined by the argument's type is accepted. Any
argument defined as a set of alternatives can generate this error.
- BadWindow
- A value for a Window argument does not name a defined
Window.
SEE ALSO
XAnyEvent(3), XIfEvent(3), XNextEvent(3), XPutBackEvent(3)
Xlib - C Language X Interface