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enum | GdkEventType |
enum | GdkEventMask |
#define | GDK_CURRENT_TIME |
#define | GDK_PRIORITY_EVENTS |
#define | GDK_PRIORITY_REDRAW |
#define | GDK_EVENT_PROPAGATE |
#define | GDK_EVENT_STOP |
#define | GDK_BUTTON_PRIMARY |
#define | GDK_BUTTON_MIDDLE |
#define | GDK_BUTTON_SECONDARY |
GdkEventSequence |
This section describes functions dealing with events from the window system.
In GTK+ applications the events are handled automatically in
gtk_main_do_event()
and passed on to the appropriate widgets, so these
functions are rarely needed. Though some of the fields in the
Event Structures are useful.
gboolean
gdk_events_pending (void
);
Checks if any events are ready to be processed for any display.
GdkEvent *
gdk_event_peek (void
);
If there is an event waiting in the event queue of some open
display, returns a copy of it. See gdk_display_peek_event()
.
a copy of the first GdkEvent on some event
queue, or NULL
if no events are in any queues. The returned
GdkEvent should be freed with gdk_event_free()
.
[nullable]
GdkEvent *
gdk_event_get (void
);
Checks all open displays for a GdkEvent to process,to be processed
on, fetching events from the windowing system if necessary.
See gdk_display_get_event()
.
the next GdkEvent to be processed, or NULL
if no events are pending. The returned GdkEvent should be freed
with gdk_event_free()
.
[nullable]
void
gdk_event_put (const GdkEvent *event
);
Appends a copy of the given event onto the front of the event
queue for event->any.window’s display, or the default event
queue if event->any.window is NULL
. See gdk_display_put_event()
.
GdkEvent *
gdk_event_new (GdkEventType type
);
Creates a new event of the given type. All fields are set to 0.
Since: 2.2
GdkEvent *
gdk_event_copy (const GdkEvent *event
);
Copies a GdkEvent, copying or incrementing the reference count of the resources associated with it (e.g. GdkWindow’s and strings).
void
gdk_event_free (GdkEvent *event
);
Frees a GdkEvent, freeing or decrementing any resources associated with it.
Note that this function should only be called with events returned from
functions such as gdk_event_peek()
, gdk_event_get()
, gdk_event_copy()
and gdk_event_new()
.
gboolean gdk_event_get_axis (const GdkEvent *event
,GdkAxisUse axis_use
,gdouble *value
);
Extract the axis value for a particular axis use from an event structure.
gboolean gdk_event_get_button (const GdkEvent *event
,guint *button
);
Extract the button number from an event.
Since: 3.2
gboolean gdk_event_get_click_count (const GdkEvent *event
,guint *click_count
);
Extracts the click count from an event.
Since: 3.2
gboolean gdk_event_get_coords (const GdkEvent *event
,gdouble *x_win
,gdouble *y_win
);
Extract the event window relative x/y coordinates from an event.
gboolean gdk_event_get_keycode (const GdkEvent *event
,guint16 *keycode
);
Extracts the hardware keycode from an event.
Also see gdk_event_get_scancode()
.
Since: 3.2
gboolean gdk_event_get_keyval (const GdkEvent *event
,guint *keyval
);
Extracts the keyval from an event.
Since: 3.2
gboolean gdk_event_get_root_coords (const GdkEvent *event
,gdouble *x_root
,gdouble *y_root
);
Extract the root window relative x/y coordinates from an event.
gboolean gdk_event_get_scroll_direction (const GdkEvent *event
,GdkScrollDirection *direction
);
Extracts the scroll direction from an event.
If event
is not of type GDK_SCROLL
, the contents of direction
are undefined.
If you wish to handle both discrete and smooth scrolling, you
should check the return value of this function, or of
gdk_event_get_scroll_deltas()
; for instance:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 |
GdkScrollDirection direction; double vscroll_factor = 0.0; double x_scroll, y_scroll; if (gdk_event_get_scroll_direction (event, &direction)) { // Handle discrete scrolling with a known constant delta; const double delta = 12.0; switch (direction) { case GDK_SCROLL_UP: vscroll_factor = -delta; break; case GDK_SCROLL_DOWN: vscroll_factor = delta; break; default: // no scrolling break; } } else if (gdk_event_get_scroll_deltas (event, &x_scroll, &y_scroll)) { // Handle smooth scrolling directly vscroll_factor = y_scroll; } |
Since: 3.2
gboolean gdk_event_get_scroll_deltas (const GdkEvent *event
,gdouble *delta_x
,gdouble *delta_y
);
Retrieves the scroll deltas from a GdkEvent
See also: gdk_event_get_scroll_direction()
event |
a GdkEvent |
|
delta_x |
return location for X delta. |
[out] |
delta_y |
return location for Y delta. |
[out] |
Since: 3.4
gboolean
gdk_event_is_scroll_stop_event (const GdkEvent *event
);
Check whether a scroll event is a stop scroll event. Scroll sequences with smooth scroll information may provide a stop scroll event once the interaction with the device finishes, e.g. by lifting a finger. This stop scroll event is the signal that a widget may trigger kinetic scrolling based on the current velocity.
Stop scroll events always have a a delta of 0/0.
Since: 3.20
gboolean gdk_event_get_state (const GdkEvent *event
,GdkModifierType *state
);
If the event contains a “state” field, puts that field in state
. Otherwise
stores an empty state (0). Returns TRUE
if there was a state field
in the event. event
may be NULL
, in which case it’s treated
as if the event had no state field.
guint32
gdk_event_get_time (const GdkEvent *event
);
Returns the time stamp from event
, if there is one; otherwise
returns GDK_CURRENT_TIME. If event
is NULL
, returns GDK_CURRENT_TIME.
GdkWindow *
gdk_event_get_window (const GdkEvent *event
);
Extracts the GdkWindow associated with an event.
Since: 3.10
GdkEventType
gdk_event_get_event_type (const GdkEvent *event
);
Retrieves the type of the event.
Since: 3.10
GdkEventSequence *
gdk_event_get_event_sequence (const GdkEvent *event
);
If event
if of type GDK_TOUCH_BEGIN
, GDK_TOUCH_UPDATE
,
GDK_TOUCH_END
or GDK_TOUCH_CANCEL
, returns the GdkEventSequence
to which the event belongs. Otherwise, return NULL
.
Since: 3.4
void
gdk_event_request_motions (const GdkEventMotion *event
);
Request more motion notifies if event
is a motion notify hint event.
This function should be used instead of gdk_window_get_pointer()
to
request further motion notifies, because it also works for extension
events where motion notifies are provided for devices other than the
core pointer. Coordinate extraction, processing and requesting more
motion events from a GDK_MOTION_NOTIFY
event usually works like this:
1 2 3 4 5 6 7 |
{ // motion_event handler x = motion_event->x; y = motion_event->y; // handle (x,y) motion gdk_event_request_motions (motion_event); // handles is_hint events } |
Since: 2.12
gboolean gdk_events_get_angle (GdkEvent *event1
,GdkEvent *event2
,gdouble *angle
);
If both events contain X/Y information, this function will return TRUE
and return in angle
the relative angle from event1
to event2
. The rotation
direction for positive angles is from the positive X axis towards the positive
Y axis.
event1 |
first GdkEvent |
|
event2 |
second GdkEvent |
|
angle |
return location for the relative angle between both events. |
[out] |
Since: 3.0
gboolean gdk_events_get_center (GdkEvent *event1
,GdkEvent *event2
,gdouble *x
,gdouble *y
);
If both events contain X/Y information, the center of both coordinates
will be returned in x
and y
.
event1 |
first GdkEvent |
|
event2 |
second GdkEvent |
|
x |
return location for the X coordinate of the center. |
[out] |
y |
return location for the Y coordinate of the center. |
[out] |
Since: 3.0
gboolean gdk_events_get_distance (GdkEvent *event1
,GdkEvent *event2
,gdouble *distance
);
If both events have X/Y information, the distance between both coordinates
(as in a straight line going from event1
to event2
) will be returned.
event1 |
first GdkEvent |
|
event2 |
second GdkEvent |
|
distance |
return location for the distance. |
[out] |
Since: 3.0
gboolean
gdk_event_triggers_context_menu (const GdkEvent *event
);
This function returns whether a GdkEventButton should trigger a
context menu, according to platform conventions. The right mouse
button always triggers context menus. Additionally, if
gdk_keymap_get_modifier_mask()
returns a non-0 mask for
GDK_MODIFIER_INTENT_CONTEXT_MENU
, then the left mouse button will
also trigger a context menu if this modifier is pressed.
This function should always be used instead of simply checking for
event->button == GDK_BUTTON_SECONDARY
.
Since: 3.4
GdkSeat *
gdk_event_get_seat (const GdkEvent *event
);
Returns the GdkSeat this event was generated for.
Since: 3.20
int
gdk_event_get_scancode (GdkEvent *event
);
Gets the keyboard low-level scancode of a key event.
This is usually hardware_keycode. On Windows this is the high word of WM_KEY{DOWN,UP} lParam which contains the scancode and some extended flags.
Since: 3.22
gboolean
gdk_event_get_pointer_emulated (GdkEvent *event
);
Returns whether this event is an 'emulated' pointer event (typically from a touch event), as opposed to a real one.
Since: 3.22
void gdk_event_handler_set (GdkEventFunc func
,gpointer data
,GDestroyNotify notify
);
Sets the function to call to handle all events from GDK.
Note that GTK+ uses this to install its own event handler, so it is
usually not useful for GTK+ applications. (Although an application
can call this function then call gtk_main_do_event()
to pass
events to GTK+.)
func |
the function to call to handle events from GDK. |
|
data |
user data to pass to the function. |
|
notify |
the function to call when the handler function is removed, i.e. when
|
void (*GdkEventFunc) (GdkEvent *event
,gpointer data
);
Specifies the type of function passed to gdk_event_handler_set()
to
handle all GDK events.
event |
the GdkEvent to process. |
|
data |
user data set when the event handler was installed with
|
[closure] |
gboolean
gdk_get_show_events (void
);
Gets whether event debugging output is enabled.
void
gdk_set_show_events (gboolean show_events
);
Sets whether a trace of received events is output.
Note that GTK+ must be compiled with debugging (that is,
configured using the --enable-debug
option)
to use this option.
void gdk_event_set_screen (GdkEvent *event
,GdkScreen *screen
);
Sets the screen for event
to screen
. The event must
have been allocated by GTK+, for instance, by
gdk_event_copy()
.
Since: 2.2
GdkScreen *
gdk_event_get_screen (const GdkEvent *event
);
Returns the screen for the event. The screen is
typically the screen for event->any.window
, but
for events such as mouse events, it is the screen
where the pointer was when the event occurs -
that is, the screen which has the root window
to which event->motion.x_root
and
event->motion.y_root
are relative.
Since: 2.2
GdkDevice *
gdk_event_get_device (const GdkEvent *event
);
If the event contains a “device” field, this function will return
it, else it will return NULL
.
Since: 3.0
void gdk_event_set_device (GdkEvent *event
,GdkDevice *device
);
Sets the device for event
to device
. The event must
have been allocated by GTK+, for instance, by
gdk_event_copy()
.
Since: 3.0
GdkDevice *
gdk_event_get_source_device (const GdkEvent *event
);
This function returns the hardware (slave) GdkDevice that has
triggered the event, falling back to the virtual (master) device
(as in gdk_event_get_device()
) if the event wasn’t caused by
interaction with a hardware device. This may happen for example
in synthesized crossing events after a GdkWindow updates its
geometry or a grab is acquired/released.
If the event does not contain a device field, this function will
return NULL
.
Since: 3.0
void gdk_event_set_source_device (GdkEvent *event
,GdkDevice *device
);
Sets the slave device for event
to device
.
The event must have been allocated by GTK+,
for instance by gdk_event_copy()
.
Since: 3.0
GdkDeviceTool *
gdk_event_get_device_tool (const GdkEvent *event
);
If the event was generated by a device that supports
different tools (eg. a tablet), this function will
return a GdkDeviceTool representing the tool that
caused the event. Otherwise, NULL
will be returned.
Note: the GdkDeviceTool<!-- -->s will be constant during
the application lifetime, if settings must be stored
persistently across runs, see gdk_device_tool_get_serial()
Since: 3.22
void gdk_event_set_device_tool (GdkEvent *event
,GdkDeviceTool *tool
);
Sets the device tool for this event, should be rarely used.
Since: 3.22
gboolean gdk_setting_get (const gchar *name
,GValue *value
);
Obtains a desktop-wide setting, such as the double-click time,
for the default screen. See gdk_screen_get_setting()
.