Top |
Functions
Description
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.
Functions
GDK_PRIORITY_EVENTS
#define GDK_PRIORITY_EVENTS
This is the priority that events from the X server are given in the GLib Main Loop.
GDK_PRIORITY_REDRAW
#define GDK_PRIORITY_REDRAW (G_PRIORITY_HIGH_IDLE + 20)
This is the priority that the idle handler processing window updates is given in the GLib Main Loop.
GDK_EVENT_PROPAGATE
#define GDK_EVENT_PROPAGATE (FALSE)
Use this macro as the return value for continuing the propagation of an event handler.
Since 3.4
GDK_EVENT_STOP
#define GDK_EVENT_STOP (TRUE)
Use this macro as the return value for stopping the propagation of an event handler.
Since 3.4
GDK_BUTTON_PRIMARY
#define GDK_BUTTON_PRIMARY (1)
The primary button. This is typically the left mouse button, or the right button in a left-handed setup.
Since 3.4
GDK_BUTTON_SECONDARY
#define GDK_BUTTON_SECONDARY (3)
The secondary button. This is typically the right mouse button, or the left button in a left-handed setup.
Since 3.4
gdk_events_pending ()
gboolean
gdk_events_pending (void
);
Checks if any events are ready to be processed for any display.
gdk_event_peek ()
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()
.
Returns
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()
.
gdk_event_get ()
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()
.
Returns
the next GdkEvent to be processed, or NULL
if no events
are pending. The returned GdkEvent should be freed with gdk_event_free()
.
gdk_event_put ()
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()
.
gdk_event_new ()
GdkEvent *
gdk_event_new (GdkEventType type
);
Creates a new event of the given type. All fields are set to 0.
Since 2.2
gdk_event_copy ()
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).
gdk_event_free ()
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()
.
gdk_event_get_axis ()
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.
Parameters
event |
a GdkEvent |
|
axis_use |
the axis use to look for |
|
value |
location to store the value found. |
[out] |
gdk_event_get_button ()
gboolean gdk_event_get_button (const GdkEvent *event
,guint *button
);
Extract the button number from an event.
Since 3.2
gdk_event_get_click_count ()
gboolean gdk_event_get_click_count (const GdkEvent *event
,guint *click_count
);
Extracts the click count from an event.
Since 3.2
gdk_event_get_coords ()
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.
Parameters
event |
a GdkEvent |
|
x_win |
location to put event window x coordinate. |
[out] |
y_win |
location to put event window y coordinate. |
[out] |
gdk_event_get_keycode ()
gboolean gdk_event_get_keycode (const GdkEvent *event
,guint16 *keycode
);
Extracts the hardware keycode from an event.
Since 3.2
gdk_event_get_keyval ()
gboolean gdk_event_get_keyval (const GdkEvent *event
,guint *keyval
);
Extracts the keyval from an event.
Since 3.2
gdk_event_get_root_coords ()
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.
Parameters
event |
a GdkEvent |
|
x_root |
location to put root window x coordinate. |
[out] |
y_root |
location to put root window y coordinate. |
[out] |
gdk_event_get_scroll_direction ()
gboolean gdk_event_get_scroll_direction (const GdkEvent *event
,GdkScrollDirection *direction
);
Extracts the scroll direction from an event.
Since 3.2
gdk_event_get_scroll_deltas ()
gboolean gdk_event_get_scroll_deltas (const GdkEvent *event
,gdouble *delta_x
,gdouble *delta_y
);
Retrieves the scroll deltas from a GdkEvent
Parameters
event |
a GdkEvent |
|
delta_x |
return location for X delta. |
[out] |
delta_y |
return location for Y delta. |
[out] |
Since 3.4
gdk_event_get_state ()
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.
gdk_event_get_time ()
guint32
gdk_event_get_time (const GdkEvent *event
);
returns GDK_CURRENT_TIME. If event
is NULL
, returns GDK_CURRENT_TIME.
gdk_event_get_window ()
GdkWindow *
gdk_event_get_window (const GdkEvent *event
);
Extracts the GdkWindow associated with an event.
Since 3.10
gdk_event_get_event_type ()
GdkEventType
gdk_event_get_event_type (const GdkEvent *event
);
Retrieves the type of the event.
Since 3.10
gdk_event_get_event_sequence ()
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
gdk_event_request_motions ()
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
gdk_events_get_angle ()
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.
Since 3.0
gdk_events_get_center ()
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
.
Since 3.0
gdk_events_get_distance ()
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.
Since 3.0
gdk_event_triggers_context_menu ()
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
gdk_event_handler_set ()
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+.)
Parameters
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
|
GdkEventFunc ()
void (*GdkEventFunc) (GdkEvent *event
,gpointer data
);
Specifies the type of function passed to gdk_event_handler_set()
to
handle all GDK events.
Parameters
event |
the GdkEvent to process. |
|
data |
user data set when the event handler was installed with
|
[closure] |
gdk_get_show_events ()
gboolean
gdk_get_show_events (void
);
Gets whether event debugging output is enabled.
gdk_set_show_events ()
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.
gdk_event_set_screen ()
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
gdk_event_get_screen ()
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
gdk_event_get_device ()
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
gdk_event_set_device ()
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
gdk_event_get_source_device ()
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
gdk_event_set_source_device ()
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
gdk_setting_get ()
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()
.
Types and Values
enum GdkEventType
Specifies the type of the event.
Do not confuse these events with the signals that GTK+ widgets emit. Although many of these events result in corresponding signals being emitted, the events are often transformed or filtered along the way.
In some language bindings, the values GDK_2BUTTON_PRESS
and
GDK_3BUTTON_PRESS
would translate into something syntactically
invalid (eg Gdk.EventType.2ButtonPress
, where a
symbol is not allowed to start with a number). In that case, the
aliases GDK_DOUBLE_BUTTON_PRESS
and GDK_TRIPLE_BUTTON_PRESS
can
be used instead.
Members
a special code to indicate a null event. |
||
the window manager has requested that the toplevel window be hidden or destroyed, usually when the user clicks on a special icon in the title bar. |
||
the window has been destroyed. |
||
all or part of the window has become visible and needs to be redrawn. |
||
the pointer (usually a mouse) has moved. |
||
a mouse button has been pressed. |
||
a mouse button has been double-clicked (clicked twice
within a short period of time). Note that each click also generates a
|
||
alias for |
||
a mouse button has been clicked 3 times in a short period
of time. Note that each click also generates a |
||
alias for |
||
a mouse button has been released. |
||
a key has been pressed. |
||
a key has been released. |
||
the pointer has entered the window. |
||
the pointer has left the window. |
||
the keyboard focus has entered or left the window. |
||
the size, position or stacking order of the window has changed.
Note that GTK+ discards these events for |
||
the window has been mapped. |
||
the window has been unmapped. |
||
a property on the window has been changed or deleted. |
||
the application has lost ownership of a selection. |
||
another application has requested a selection. |
||
a selection has been received. |
||
an input device has moved into contact with a sensing surface (e.g. a touchscreen or graphics tablet). |
||
an input device has moved out of contact with a sensing surface. |
||
the mouse has entered the window while a drag is in progress. |
||
the mouse has left the window while a drag is in progress. |
||
the mouse has moved in the window while a drag is in progress. |
||
the status of the drag operation initiated by the window has changed. |
||
a drop operation onto the window has started. |
||
the drop operation initiated by the window has completed. |
||
a message has been received from another application. |
||
the window visibility status has changed. |
||
the scroll wheel was turned |
||
the state of a window has changed. See GdkWindowState for the possible window states |
||
a setting has been modified. |
||
the owner of a selection has changed. This event type was added in 2.6 |
||
a pointer or keyboard grab was broken. This event type was added in 2.8. |
||
the content of the window has been changed. This event type was added in 2.14. |
||
A new touch event sequence has just started. This event type was added in 3.4. |
||
A touch event sequence has been updated. This event type was added in 3.4. |
||
A touch event sequence has finished. This event type was added in 3.4. |
||
A touch event sequence has been canceled. This event type was added in 3.4. |
||
marks the end of the GdkEventType enumeration. Added in 2.18 |
enum GdkEventMask
A set of bit-flags to indicate which events a window is to receive. Most of these masks map onto one or more of the GdkEventType event types above.
GDK_POINTER_MOTION_HINT_MASK
is deprecated. It is a special mask
to reduce the number of GDK_MOTION_NOTIFY
events received. When using
GDK_POINTER_MOTION_HINT_MASK
, fewer GDK_MOTION_NOTIFY
events will
be sent, some of which are marked as a hint (the is_hint member is
TRUE
). To receive more motion events after a motion hint event,
the application needs to asks for more, by calling
gdk_event_request_motions()
.
Since GTK 3.8, motion events are already compressed by default, independent
of this mechanism. This compression can be disabled with
gdk_window_set_event_compression()
. See the documentation of that function
for details.
If GDK_TOUCH_MASK
is enabled, the window will receive touch events
from touch-enabled devices. Those will come as sequences of GdkEventTouch
with type GDK_TOUCH_UPDATE
, enclosed by two events with
type GDK_TOUCH_BEGIN
and GDK_TOUCH_END
(or GDK_TOUCH_CANCEL
).
gdk_event_get_event_sequence()
returns the event sequence for these
events, so different sequences may be distinguished.
Members
receive expose events |
||
receive all pointer motion events |
||
deprecated. see the explanation above |
||
receive pointer motion events while any button is pressed |
||
receive pointer motion events while 1 button is pressed |
||
receive pointer motion events while 2 button is pressed |
||
receive pointer motion events while 3 button is pressed |
||
receive button press events |
||
receive button release events |
||
receive key press events |
||
receive key release events |
||
receive window enter events |
||
receive window leave events |
||
receive focus change events |
||
receive events about window configuration change |
||
receive property change events |
||
receive visibility change events |
||
receive proximity in events |
||
receive proximity out events |
||
receive events about window configuration changes of child windows |
||
receive scroll events |
||
receive touch events. Since 3.4 |
||
receive smooth scrolling events. Since 3.4 |
||
the combination of all the above event masks. |
GDK_CURRENT_TIME
#define GDK_CURRENT_TIME 0L
Represents the current time, and can be used anywhere a time is expected.