Struct gtk4::EventControllerScroll

pub struct EventControllerScroll { /* private fields */ }

EventControllerScroll is an event controller that handles scroll events.

It is capable of handling both discrete and continuous scroll events from mice or touchpads, abstracting them both with the scroll signal. Deltas in the discrete case are multiples of 1.

In the case of continuous scroll events, EventControllerScroll encloses all scroll emissions between two scroll-begin and scroll-end signals.

The behavior of the event controller can be modified by the flags given at creation time, or modified at a later point through set_flags() (e.g. because the scrolling conditions of the widget changed).

The controller can be set up to emit motion for either/both vertical and horizontal scroll events through EventControllerScrollFlags::VERTICAL, EventControllerScrollFlags::HORIZONTAL and EventControllerScrollFlags::BOTH_AXES. If any axis is disabled, the respective scroll delta will be 0. Vertical scroll events will be translated to horizontal motion for the devices incapable of horizontal scrolling.

The event controller can also be forced to emit discrete events on all devices through EventControllerScrollFlags::DISCRETE. This can be used to implement discrete actions triggered through scroll events (e.g. switching across combobox options).

The EventControllerScrollFlags::KINETIC flag toggles the emission of the decelerate signal, emitted at the end of scrolling with two X/Y velocity arguments that are consistent with the motion that was received.

Properties

flags

The flags affecting event controller behavior.

Readable | Writeable

EventController

name

The name for this controller, typically used for debugging purposes.

Readable | Writeable

propagation-limit

The limit for which events this controller will handle.

Readable | Writeable

propagation-phase

The propagation phase at which this controller will handle events.

Readable | Writeable

widget

The widget receiving the GdkEvents that the controller will handle.

Readable

Signals

decelerate

Emitted after scroll is finished if the EventControllerScrollFlags::KINETIC flag is set.

@vel_x and @vel_y express the initial velocity that was imprinted by the scroll events. @vel_x and @vel_y are expressed in pixels/ms.

scroll

Signals that the widget should scroll by the amount specified by @dx and @dy.

For the representation unit of the deltas, see EventControllerScroll::unit().

scroll-begin

Signals that a new scrolling operation has begun.

It will only be emitted on devices capable of it.

scroll-end

Signals that a scrolling operation has finished.

It will only be emitted on devices capable of it.

Implements

EventControllerExt, [trait@glib::ObjectExt]

Implementations

impl EventControllerScroll

pub fn new(flags: EventControllerScrollFlags) -> EventControllerScroll

Creates a new event controller that will handle scroll events.

flags

flags affecting the controller behavior

Returns

a new EventControllerScroll

pub fn builder() -> EventControllerScrollBuilder

Creates a new builder-pattern struct instance to construct EventControllerScroll objects.

This method returns an instance of EventControllerScrollBuilder which can be used to create EventControllerScroll objects.

pub fn flags(&self) -> EventControllerScrollFlags

Gets the flags conditioning the scroll controller behavior.

Returns

the controller flags.

pub fn unit(&self) -> ScrollUnit

Available on crate feature v4_8 only.

Gets the scroll unit of the last scroll signal received.

Always returns gdk::ScrollUnit::Wheel if the EventControllerScrollFlags::DISCRETE flag is set.

Returns

the scroll unit.

pub fn set_flags(&self, flags: EventControllerScrollFlags)

Sets the flags conditioning scroll controller behavior.

flags

flags affecting the controller behavior

pub fn connect_decelerate<F: Fn(&Self, f64, f64) + 'static>( &self, f: F ) -> SignalHandlerId

Emitted after scroll is finished if the EventControllerScrollFlags::KINETIC flag is set.

@vel_x and @vel_y express the initial velocity that was imprinted by the scroll events. @vel_x and @vel_y are expressed in pixels/ms.

vel_x

X velocity

vel_y

Y velocity

pub fn connect_scroll<F: Fn(&Self, f64, f64) -> Propagation + 'static>( &self, f: F ) -> SignalHandlerId

Signals that the widget should scroll by the amount specified by @dx and @dy.

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

dx

X delta

dy

Y delta

Returns

true if the scroll event was handled, false otherwise.

pub fn connect_scroll_begin<F: Fn(&Self) + 'static>( &self, f: F ) -> SignalHandlerId

Signals that a new scrolling operation has begun.

It will only be emitted on devices capable of it.

pub fn connect_scroll_end<F: Fn(&Self) + 'static>( &self, f: F ) -> SignalHandlerId

Signals that a scrolling operation has finished.

It will only be emitted on devices capable of it.

pub fn connect_flags_notify<F: Fn(&Self) + 'static>( &self, f: F ) -> SignalHandlerId

Trait Implementations

impl Clone for EventControllerScroll

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 EventControllerScroll

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

Formats the value using the given formatter.

impl Default for EventControllerScroll

fn default() -> Self

Returns the “default value” for a type.

impl HasParamSpec for EventControllerScroll

type ParamSpec = ParamSpecObject

type SetValue = EventControllerScroll

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, EventControllerScroll>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for EventControllerScroll

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for EventControllerScroll

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl ParentClassIs for EventControllerScroll

type Parent = EventController

impl<OT: ObjectType> PartialEq<OT> for EventControllerScroll

fn eq(&self, other: &OT) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for EventControllerScroll

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for EventControllerScroll

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for EventControllerScroll

impl IsA<EventController> for EventControllerScroll