GI.Gdk.Unions.Event

A Event contains a union of all of the event types, and allows access to the data fields in a number of ways.

The event type is always the first field in all of the event types, and can always be accessed with the following code, no matter what type of event it is:

C code

 GdkEvent *event;
 GdkEventType type;

 type = event->type;

To access other fields of the event, the pointer to the event can be cast to the appropriate event type, or the union member name can be used. For example if the event type is EventTypeButtonPress then the x coordinate of the button press can be accessed with:

C code

 GdkEvent *event;
 gdouble x;

 x = ((GdkEventButton*)event)->x;

or:

C code

 GdkEvent *event;
 gdouble x;

 x = event->button.x;

Exported types

newtype Event

Constructors

Event (ManagedPtr Event)

Instances

BoxedObject Event

Methods

boxedType :: Event -> IO GType

(~) AttrOpTag tag AttrSet => Constructible Event tag

Methods

new :: MonadIO m => (ManagedPtr Event -> Event) -> [AttrOp Event tag] -> m Event

newZeroEvent :: MonadIO m => m Event

Construct a Event struct initialized to zero.

noEvent :: Maybe Event

Methods

copy

eventCopy

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Event

Returns: a copy of event. The returned Event should be freed with eventFree.

Copies a Event, copying or incrementing the reference count of the resources associated with it (e.g. Window’s and strings).

free

eventFree

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event.

-> m ()

Frees a Event, freeing or decrementing any resources associated with it. Note that this function should only be called with events returned from functions such as eventPeek, eventGet, eventCopy and eventNew.

get

eventGet

Arguments

:: (HasCallStack, MonadIO m)

=> m (Maybe Event)

Returns: the next Event to be processed, or Nothing if no events are pending. The returned Event should be freed with eventFree.

Checks all open displays for a Event to process,to be processed on, fetching events from the windowing system if necessary. See displayGetEvent.

getAxis

eventGetAxis

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> AxisUse

axisUse: the axis use to look for

-> m (Bool, Double)

Returns: True if the specified axis was found, otherwise False

Extract the axis value for a particular axis use from an event structure.

getButton

eventGetButton

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Word32)

Returns: True if the event delivered a button number

Extract the button number from an event.

Since: 3.2

getClickCount

eventGetClickCount

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Word32)

Returns: True if the event delivered a click count

Extracts the click count from an event.

Since: 3.2

getCoords

eventGetCoords

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Double, Double)

Returns: True if the event delivered event window coordinates

Extract the event window relative x/y coordinates from an event.

getDevice

eventGetDevice

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event.

-> m (Maybe Device)

Returns: a Device, or Nothing.

If the event contains a “device” field, this function will return it, else it will return Nothing.

Since: 3.0

getDeviceTool

eventGetDeviceTool

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m DeviceTool

Returns: The current device tool, or Nothing

If the event was generated by a device that supports different tools (eg. a tablet), this function will return a DeviceTool representing the tool that caused the event. Otherwise, Nothing will be returned.

Note: the DeviceTool<!-- -->s will be constant during the application lifetime, if settings must be stored persistently across runs, see deviceToolGetSerial

Since: 3.22

getEventSequence

eventGetEventSequence

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m EventSequence

Returns: the event sequence that the event belongs to

If event if of type EventTypeTouchBegin, EventTypeTouchUpdate, EventTypeTouchEnd or EventTypeTouchCancel, returns the EventSequence to which the event belongs. Otherwise, return Nothing.

Since: 3.4

getEventType

eventGetEventType

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m EventType

Returns: a EventType

Retrieves the type of the event.

Since: 3.10

getKeycode

eventGetKeycode

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Word16)

Returns: True if the event delivered a hardware keycode

Extracts the hardware keycode from an event.

Also see eventGetScancode.

Since: 3.2

getKeyval

eventGetKeyval

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Word32)

Returns: True if the event delivered a key symbol

Extracts the keyval from an event.

Since: 3.2

getPointerEmulated

eventGetPointerEmulated

Arguments

:: (HasCallStack, MonadIO m)

=> Event

-> m Bool

Returns: True if this event is emulated

event: a Event Returns whether this event is an 'emulated' pointer event (typically from a touch event), as opposed to a real one.

Since: 3.22

getRootCoords

eventGetRootCoords

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Double, Double)

Returns: True if the event delivered root window coordinates

Extract the root window relative x/y coordinates from an event.

getScancode

eventGetScancode

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Int32

Returns: The associated keyboard scancode or 0

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

getScreen

eventGetScreen

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Screen

Returns: the screen for the 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

getScrollDeltas

eventGetScrollDeltas

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, Double, Double)

Returns: True if the event contains smooth scroll information

Retrieves the scroll deltas from a Event

Since: 3.4

getScrollDirection

eventGetScrollDirection

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Bool, ScrollDirection)

Returns: True if the event delivered a scroll direction

Extracts the scroll direction from an event.

Since: 3.2

getSeat

eventGetSeat

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Seat

Returns: The Seat of this event

Returns the Seat this event was generated for.

Since: 3.20

getSourceDevice

eventGetSourceDevice

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m (Maybe Device)

Returns: a Device, or Nothing.

This function returns the hardware (slave) Device that has triggered the event, falling back to the virtual (master) device (as in eventGetDevice) if the event wasn’t caused by interaction with a hardware device. This may happen for example in synthesized crossing events after a Window updates its geometry or a grab is acquired/released.

If the event does not contain a device field, this function will return Nothing.

Since: 3.0

getState

eventGetState

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event or Nothing

-> m (Bool, [ModifierType])

Returns: True if there was a state field in the event

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 Nothing, in which case it’s treated as if the event had no state field.

getTime

eventGetTime

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Word32

Returns: time stamp field from event

Returns the time stamp from event, if there is one; otherwise returns CURRENT_TIME. If event is Nothing, returns CURRENT_TIME.

getWindow

eventGetWindow

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Window

Returns: The Window associated with the event

Extracts the Window associated with an event.

Since: 3.10

handlerSet

eventHandlerSet

Arguments

:: (HasCallStack, MonadIO m)

=> EventFunc

func: the function to call to handle events from GDK.

-> m ()

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+.)

isScrollStopEvent

eventIsScrollStopEvent

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event

-> m Bool

Returns: True if the event is a scroll stop 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

new

eventNew

Arguments

:: (HasCallStack, MonadIO m)

=> EventType

type: a EventType

-> m Event

Returns: a newly-allocated Event. The returned Event should be freed with eventFree.

Creates a new event of the given type. All fields are set to 0.

Since: 2.2

peek

eventPeek

Arguments

:: (HasCallStack, MonadIO m)

=> m (Maybe Event)

Returns: a copy of the first Event on some event queue, or Nothing if no events are in any queues. The returned Event should be freed with eventFree.

If there is an event waiting in the event queue of some open display, returns a copy of it. See displayPeekEvent.

put

eventPut

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event.

-> m ()

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 Nothing. See displayPutEvent.

requestMotions

eventRequestMotions

Arguments

:: (HasCallStack, MonadIO m)

=> EventMotion

event: a valid Event

-> m ()

Request more motion notifies if event is a motion notify hint event.

This function should be used instead of windowGetPointer 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 EventTypeMotionNotify event usually works like this:

C code

{
  // 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

setDevice

eventSetDevice

Arguments

:: (HasCallStack, MonadIO m, IsDevice a)

=> Event

event: a Event

-> a

device: a Device

-> m ()

Sets the device for event to device. The event must have been allocated by GTK+, for instance, by eventCopy.

Since: 3.0

setDeviceTool

eventSetDeviceTool

Arguments

:: (HasCallStack, MonadIO m, IsDeviceTool a)

=> Event

event: a Event

-> Maybe a

tool: tool to set on the event, or Nothing

-> m ()

Sets the device tool for this event, should be rarely used.

Since: 3.22

setScreen

eventSetScreen

Arguments

:: (HasCallStack, MonadIO m, IsScreen a)

=> Event

event: a Event

-> a

screen: a Screen

-> m ()

Sets the screen for event to screen. The event must have been allocated by GTK+, for instance, by eventCopy.

Since: 2.2

setSourceDevice

eventSetSourceDevice

Arguments

:: (HasCallStack, MonadIO m, IsDevice a)

=> Event

event: a Event

-> a

device: a Device

-> m ()

Sets the slave device for event to device.

The event must have been allocated by GTK+, for instance by eventCopy.

Since: 3.0

triggersContextMenu

eventTriggersContextMenu

Arguments

:: (HasCallStack, MonadIO m)

=> Event

event: a Event, currently only button events are meaningful values

-> m Bool

Returns: True if the event should trigger a context menu.

This function returns whether a EventButton should trigger a context menu, according to platform conventions. The right mouse button always triggers context menus. Additionally, if keymapGetModifierMask returns a non-0 mask for ModifierIntentContextMenu, 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 == BUTTON_SECONDARY.

Since: 3.4

Properties

any

getEventAny :: MonadIO m => Event -> m EventAny

button

getEventButton :: MonadIO m => Event -> m EventButton

configure

getEventConfigure :: MonadIO m => Event -> m EventConfigure

crossing

getEventCrossing :: MonadIO m => Event -> m EventCrossing

dnd

getEventDnd :: MonadIO m => Event -> m EventDND

expose

getEventExpose :: MonadIO m => Event -> m EventExpose

focusChange

getEventFocusChange :: MonadIO m => Event -> m EventFocus

grabBroken

getEventGrabBroken :: MonadIO m => Event -> m EventGrabBroken

key

getEventKey :: MonadIO m => Event -> m EventKey

motion

getEventMotion :: MonadIO m => Event -> m EventMotion

ownerChange

getEventOwnerChange :: MonadIO m => Event -> m EventOwnerChange

padAxis

getEventPadAxis :: MonadIO m => Event -> m EventPadAxis

padButton

getEventPadButton :: MonadIO m => Event -> m EventPadButton

padGroupMode

getEventPadGroupMode :: MonadIO m => Event -> m EventPadGroupMode

property

getEventProperty :: MonadIO m => Event -> m EventProperty

proximity

getEventProximity :: MonadIO m => Event -> m EventProximity

scroll

getEventScroll :: MonadIO m => Event -> m EventScroll

selection

getEventSelection :: MonadIO m => Event -> m EventSelection

setting

getEventSetting :: MonadIO m => Event -> m EventSetting

touch

getEventTouch :: MonadIO m => Event -> m EventTouch

touchpadPinch

getEventTouchpadPinch :: MonadIO m => Event -> m EventTouchpadPinch

touchpadSwipe

getEventTouchpadSwipe :: MonadIO m => Event -> m EventTouchpadSwipe

type

getEventType :: MonadIO m => Event -> m EventType

setEventType :: MonadIO m => Event -> EventType -> m ()

visibility

getEventVisibility :: MonadIO m => Event -> m EventVisibility

windowState

getEventWindowState :: MonadIO m => Event -> m EventWindowState