Struct gdk4::ScrollEvent

#[repr(transparent)]
pub struct ScrollEvent { /* private fields */ }

An event related to a scrolling motion.

Implementations

impl ScrollEvent

pub fn as_ptr(&self) -> *mut GdkScrollEvent

Return the inner pointer to the underlying C value.

pub unsafe fn from_glib_ptr_borrow<'a>( ptr: *const *const GdkScrollEvent ) -> &'a Self

Borrows the underlying C value.

impl ScrollEvent

pub fn deltas(&self) -> (f64, f64)

Extracts the scroll deltas of a scroll event.

The deltas will be zero unless the scroll direction is ScrollDirection::Smooth.

For the representation unit of these deltas, see unit().

Returns

delta_x

return location for x scroll delta

delta_y

return location for y scroll delta

pub fn direction(&self) -> ScrollDirection

Extracts the direction of a scroll event.

Returns

the scroll direction of @self

pub fn unit(&self) -> ScrollUnit

Available on crate feature v4_8 only.

Extracts the scroll delta unit of a scroll event.

The unit will always be ScrollUnit::Wheel if the scroll direction is not ScrollDirection::Smooth.

Returns

the scroll unit.

pub fn is_stop(&self) -> bool

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 delta of 0/0.

Returns

true if the event is a scroll stop event

impl ScrollEvent

pub fn upcast(self) -> Event

pub fn upcast_ref(&self) -> &Event

Methods from Deref<Target = Event>

pub fn as_ptr(&self) -> *mut GdkEvent

Return the inner pointer to the underlying C value.

pub const NONE: Option<&'static Event> = None

pub fn axes(&self) -> Option<Vec<f64>>

Extracts all axis values from an event.

To find out which axes are used, use DeviceTool::axes() on the device tool returned by device_tool().

Returns

true on success, otherwise false

axes

the array of values for all axes

pub fn axis(&self, axis_use: AxisUse) -> Option<f64>

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

To find out which axes are used, use DeviceTool::axes() on the device tool returned by device_tool().

axis_use

the axis use to look for

Returns

true if the specified axis was found, otherwise false

value

location to store the value found

pub fn device(&self) -> Option<Device>

Returns the device of an event.

Returns

a Device

pub fn device_tool(&self) -> Option<DeviceTool>

Returns a DeviceTool representing the tool that caused the event.

If the was not generated by a device that supports different tools (such as a tablet), this function will return None.

Note: the DeviceTool will be constant during the application lifetime, if settings must be stored persistently across runs, see DeviceTool::serial().

Returns

The current device tool

pub fn display(&self) -> Option<Display>

Retrieves the display associated to the @self.

Returns

a Display

pub fn event_sequence(&self) -> EventSequence

Returns the event sequence to which the event belongs.

Related touch events are connected in a sequence. Other events typically don’t have event sequence information.

Returns

the event sequence that the event belongs to

pub fn event_type(&self) -> EventType

Retrieves the type of the event.

Returns

a EventType

pub fn history(&self) -> Vec<TimeCoord>

Retrieves the history of the device that @self is for, as a list of time and coordinates.

The history includes positions that are not delivered as separate events to the application because they occurred in the same frame as @self.

Note that only motion and scroll events record history, and motion events do it only if one of the mouse buttons is down, or the device has a tool.

Returns

an array of time and coordinates

pub fn modifier_state(&self) -> ModifierType

Returns the modifier state field of an event.

Returns

the modifier state of @self

pub fn is_pointer_emulated(&self) -> bool

Returns whether this event is an ‘emulated’ pointer event.

Emulated pointer events typically originate from a touch events.

Returns

true if this event is emulated

pub fn position(&self) -> Option<(f64, f64)>

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

This position is in surface coordinates.

Returns

x

location to put event surface x coordinate

y

location to put event surface y coordinate

pub fn seat(&self) -> Option<Seat>

Returns the seat that originated the event.

Returns

a Seat.

pub fn surface(&self) -> Option<Surface>

Extracts the surface associated with an event.

Returns

The Surface associated with the event

pub fn time(&self) -> u32

Returns the timestamp of @self.

Not all events have timestamps. In that case, this function returns GDK_CURRENT_TIME.

Returns

timestamp field from @self

pub fn triggers_context_menu(&self) -> bool

Returns whether a Event should trigger a context menu, according to platform conventions.

The right mouse button typically triggers context menus.

This function should always be used instead of simply checking for event->button == GDK_BUTTON_SECONDARY.

Returns

true if the event should trigger a context menu.

pub fn is<T: EventKind>(&self) -> bool

pub fn type_(&self) -> Type

pub fn downcast_ref<T: EventKind>(&self) -> Option<&T>

pub fn angle(&self, event: impl AsRef<Event>) -> Option<f64>

Returns the relative angle from @event1 to @event2.

The relative angle is the angle between the X axis and the line through both events’ positions. The rotation direction for positive angles is from the positive X axis towards the positive Y axis.

This assumes that both events have X/Y information. If not, this function returns false.

event1

first Event

event2

second Event

Returns

true if the angle could be calculated.

angle

return location for the relative angle between both events

pub fn center(&self, event: impl AsRef<Event>) -> Option<(f64, f64)>

Returns the point halfway between the events’ positions.

This assumes that both events have X/Y information. If not, this function returns false.

event1

first Event

event2

second Event

Returns

true if the center could be calculated.

x

return location for the X coordinate of the center

y

return location for the Y coordinate of the center

pub fn distance(&self, event: impl AsRef<Event>) -> Option<f64>

Returns the distance between the event locations.

This assumes that both events have X/Y information. If not, this function returns false.

event1

first Event

event2

second Event

Returns

true if the distance could be calculated.

distance

return location for the distance

Trait Implementations

impl AsRef<Event> for ScrollEvent

fn as_ref(&self) -> &Event

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for ScrollEvent

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ScrollEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for ScrollEvent

type Target = Event

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Display for ScrollEvent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl EventKind for ScrollEvent

fn event_types() -> &'static [EventType]

impl StaticType for ScrollEvent

fn static_type() -> Type

Returns the type identifier of Self.