Struct Presence 

pub struct Presence { /* private fields */ }

An element’s arrival and departure, either of which can be cancelled by the other while it is still running.

A cancelled phase is played backwards from where it had got to rather than restarted. The two phases are separate specifications with separate durations and separate curves, so “where it had got to” is a position and not a time: the visible progress is looked up in the other specification — MotionSpec::time_at — and the reversal starts from the point that produces it. An entrance cancelled at 30% therefore leaves from 30%, through the exit’s own curve, in the part of the exit’s time that is left once 70% of it is already behind.

This is deliberately not the velocity handover Transition performs on a retarget. A value aimed somewhere new is still going the way it was going; a phase that is cancelled has been told to go back, and carrying the speed across would mean an element on its way in overshooting past being present, which is not a state a lifecycle has.

Implementations

impl Presence

pub fn hidden(enter: MotionSpec, exit: MotionSpec) -> Self

Starts hidden, so the first Presence::show animates in.

pub fn visible(enter: MotionSpec, exit: MotionSpec) -> Self

Starts fully present, for content that exists before the first frame.

pub fn phase(&self) -> Phase

pub fn is_rendered(&self) -> bool

True while the caller must keep the element in the tree, including for the whole exit animation.

pub fn is_animating(&self) -> bool

pub fn progress(&self) -> f32

0 while absent, 1 while fully present.

pub fn show(&mut self)

Enters, or reverses an exit that is still in flight.

pub fn hide(&mut self)

pub fn toggle(&mut self)

pub fn settle(&mut self)

Finishes the current phase instantly.

pub fn advance(&mut self, delta: Duration)

pub fn animate(&mut self, window: &mut Window, cx: &mut App) -> f32

Advances by the time since the previous frame and requests the next one while a phase is running. Reduced motion skips straight to the end.

Trait Implementations

impl Clone for Presence

fn clone(&self) -> Presence

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Presence

impl Debug for Presence

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

Formats the value using the given formatter.

impl PartialEq for Presence

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Presence