Struct gtk4::GestureZoom

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

GestureZoom is a Gesture for 2-finger pinch/zoom gestures.

Whenever the distance between both tracked sequences changes, the scale-changed signal is emitted to report the scale factor.

Signals

scale-changed

Emitted whenever the distance between both tracked sequences changes.

Gesture

begin

Emitted when the gesture is recognized.

This means the number of touch sequences matches n-points.

Note: These conditions may also happen when an extra touch (eg. a third touch on a 2-touches gesture) is lifted, in that situation @sequence won’t pertain to the current set of active touches, so don’t rely on this being true.

cancel

Emitted whenever a sequence is cancelled.

This usually happens on active touches when EventControllerExt::reset() is called on @gesture (manually, due to grabs…), or the individual @sequence was claimed by parent widgets’ controllers (see GestureExt::set_sequence_state()).

@gesture must forget everything about @sequence as in response to this signal.

end

Emitted when @gesture either stopped recognizing the event sequences as something to be handled, or the number of touch sequences became higher or lower than n-points.

Note: @sequence might not pertain to the group of sequences that were previously triggering recognition on @gesture (ie. a just pressed touch sequence that exceeds n-points). This situation may be detected by checking through GestureExt::handles_sequence().

sequence-state-changed

Emitted whenever a sequence state changes.

See GestureExt::set_sequence_state() to know more about the expectable sequence lifetimes.

update

Emitted whenever an event is handled while the gesture is recognized.

@sequence is guaranteed to pertain to the set of active touches.

Implements

GestureExt, EventControllerExt, glib::ObjectExt

Implementations

impl GestureZoom

pub fn new() -> GestureZoom

Returns a newly created Gesture that recognizes pinch/zoom gestures.

Returns

a newly created GestureZoom

pub fn builder() -> GestureZoomBuilder

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

This method returns an instance of GestureZoomBuilder which can be used to create GestureZoom objects.

pub fn scale_delta(&self) -> f64

Gets the scale delta.

If @self is active, this function returns the zooming difference since the gesture was recognized (hence the starting point is considered 1:1). If @self is not active, 1 is returned.

Returns

the scale delta

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

Emitted whenever the distance between both tracked sequences changes.

scale

Scale delta, taking the initial state as 1:1

Trait Implementations

impl Clone for GestureZoom

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 GestureZoom

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

Formats the value using the given formatter.

impl Default for GestureZoom

fn default() -> Self

Returns the “default value” for a type.

impl Display for GestureZoom

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

Formats the value using the given formatter.

impl HasParamSpec for GestureZoom

type ParamSpec = ParamSpecObject

type SetValue = GestureZoom

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

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

fn param_spec_builder() -> Self::BuilderFn

impl Hash for GestureZoom

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 GestureZoom

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParentClassIs for GestureZoom

type Parent = Gesture

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

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 GestureZoom

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 GestureZoom

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for GestureZoom

impl IsA<EventController> for GestureZoom

impl IsA<Gesture> for GestureZoom