Struct gtk4::EventControllerScroll [−][src]
pub struct EventControllerScroll(_);Expand description
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
signal::EventControllerScroll::scroll signal. Deltas in
the discrete case are multiples of 1.
In the case of continuous scroll events, EventControllerScroll
encloses all signal::EventControllerScroll::scroll emissions
between two signal::EventControllerScroll::scroll-begin and
signal::EventControllerScroll::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 signal::EventControllerScroll::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
signal::EventControllerScroll::decelerate signal, emitted at the end
of scrolling with two X/Y velocity arguments that are consistent with the
motion that was received.
Implements
Implementations
Creates a new event controller that will handle scroll events.
flags
flags affecting the controller behavior
Returns
a new EventControllerScroll
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.
Sets the flags conditioning scroll controller behavior.
flags
flags affecting the controller behavior
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) -> Inhibit + 'static>(
&self,
f: F
) -> SignalHandlerId
pub fn connect_scroll<F: Fn(&Self, f64, f64) -> Inhibit + 'static>(
&self,
f: F
) -> SignalHandlerId
Signals that a new scrolling operation has begun.
It will only be emitted on devices capable of it.
Signals that a scrolling operation has finished.
It will only be emitted on devices capable of it.
Trait Implementations
type Parent = EventController
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=
operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
Returns the type identifier of Self.
Auto Trait Implementations
impl RefUnwindSafe for EventControllerScroll
impl !Send for EventControllerScroll
impl !Sync for EventControllerScroll
impl Unpin for EventControllerScroll
impl UnwindSafe for EventControllerScroll
Blanket Implementations
Mutably borrows from an owned value. Read more
Upcasts an object to a superclass or interface T. Read more
Upcasts an object to a reference of its superclass or interface T. Read more
Tries to downcast to a subclass or interface implementor T. Read more
Tries to downcast to a reference of its subclass or interface implementor T. Read more
Tries to cast to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Tries to cast to reference to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Casts to T unconditionally. Read more
Casts to &T unconditionally. Read more
Returns true if the object is an instance of (can be cast to) T.
pub fn set_property<'a, N, V>(
&self,
property_name: N,
value: V
) -> Result<(), BoolError> where
N: Into<&'a str>,
V: ToValue,
pub fn set_property_from_value<'a, N>(
&self,
property_name: N,
value: &Value
) -> Result<(), BoolError> where
N: Into<&'a str>,
pub fn set_properties_from_value(
&self,
property_values: &[(&str, Value)]
) -> Result<(), BoolError>
pub fn has_property<'a, N>(&self, property_name: N, type_: Option<Type>) -> bool where
N: Into<&'a str>,
pub fn find_property<'a, N>(&self, property_name: N) -> Option<ParamSpec> where
N: Into<&'a str>,
Safety Read more
Safety Read more
Safety Read more
Safety Read more
pub fn connect<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: 'static + Fn(&[Value]) -> Option<Value> + Send + Sync,
Same as connect but takes a SignalId instead of a signal name.
pub fn connect_local<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: 'static + Fn(&[Value]) -> Option<Value>,
Same as connect_local but takes a SignalId instead of a signal name.
pub unsafe fn connect_unsafe<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: Fn(&[Value]) -> Option<Value>,
Same as connect_unsafe but takes a SignalId instead of a signal name.
Emit signal by signal id.
Same as emit but takes Value for the arguments.
Emit signal by its name.
Same as emit_by_name but takes Value for the arguments.
Emit signal with details by signal id.
Same as emit_with_details but takes Value for the arguments.
pub fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec) + Send + Sync,
pub fn connect_notify_local<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec),
pub unsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: Fn(&T, &ParamSpec),
pub fn bind_property<'a, O, N, M>(
&'a self,
source_property: N,
target: &'a O,
target_property: M
) -> BindingBuilder<'a> where
O: ObjectType,
N: Into<&'a str>,
M: Into<&'a str>,
Returns a SendValue clone of self.