Struct Motions 

pub struct Motions<K> { /* private fields */ }

Component-owned transitions keyed by stable part or item IDs.

Each key retains an independent MotionState. Batch results follow input order; reordering declarations does not change identity. Existing entries sample without allocating. Each new key allocates its state and may grow the hash table. Key construction/destruction may also allocate depending on K.

Omitted keys are neither sampled nor removed. Their elapsed time still passes: submitting them again samples their old trajectory at the new time. Continue submitting present(false) through an exit, then call Self::remove after its frame is no longer mounted. Dropping the collection cancels all its motion.

use gpui_ce_motion::{Motion, Motions, Target};
use std::time::Duration;

let mut motions = Motions::with_capacity(2);
let panel = Motion::new(Target::default().height(240.0))
    .initial(Target::default().height(80.0));
let title = Motion::new(Target::default()).initial(Target::default().opacity(0.0));

let [panel, title] = motions.sample(
    [("panel", panel), ("title", title)],
    Duration::ZERO,
    false,
);

assert_eq!(panel.target().height_px(), Some(80.0));
assert_eq!(title.target().alpha(), 0.0);
assert_eq!(motions.len(), 2);

Implementations

impl<K> Motions<K>

pub fn new() -> Self

Creates an empty collection without allocating.

pub fn with_capacity(capacity: usize) -> Self

Reserves space for at least capacity keys, without creating trajectories.

pub fn len(&self) -> usize

Number of retained keys, including settled or absent objects.

pub fn is_empty(&self) -> bool

Whether no keys are retained.

pub fn capacity(&self) -> usize

Number of keys that fit before the hash table must grow.

pub fn clear(&mut self)

Cancels all trajectories and drops their keys, keeping table capacity. The collection’s clock continues. Call Self::shrink_to_fit to release unused table storage, or drop the collection to release everything.

impl<K: Eq + Hash> Motions<K>

pub fn sample<const N: usize>( &mut self, declarations: [(K, Motion); N], now: Duration, reduced_motion: bool, ) -> [Frame; N]

Samples a batch at one absolute monotonic timestamp, returning owned frames.

Springs preserve velocity when retargeted. Reduced motion snaps each submitted entry; backward timestamps clamp to the collection’s last sample. An empty batch is valid and leaves entries retained. Expected cost is O(N) hash lookups plus sampling, independent of the number of omitted entries. Do not mix explicit timestamps with native frame calls on this collection.

Panics

Panics if a key occurs twice in this batch. This is a declaration error, not a transaction: entries preceding the duplicate may already be sampled.

pub fn sample_one( &mut self, key: K, motion: Motion, now: Duration, reduced_motion: bool, ) -> Frame

Samples one key, creating its state on first use. Repeated calls for the same key are allowed; each declaration retargets the same trajectory. Uses the same clock and interruption contract as Self::sample.

pub fn contains_key(&self, key: &K) -> bool

Whether this key has retained state, including a completed exit.

pub fn remove(&mut self, key: &K) -> bool

Immediately cancels and removes a key; returns whether it existed. Reusing a removed key starts fresh, including its initial declaration. For animated removal, wait until its sampled frame is no longer mounted. Hash table capacity is preserved.

pub fn retain(&mut self, keep: impl FnMut(&K) -> bool)

Immediately removes keys for which keep returns false, preserving capacity. This does not wait for exits; keep exiting keys until their final sample. Iteration order is unspecified; visits the table in O(capacity) time.

pub fn reserve(&mut self, additional: usize)

Reserves space for at least additional new keys beyond the current length.

pub fn shrink_to_fit(&mut self)

Releases unused table capacity as far as the standard hash table allows. Retained trajectories are unchanged. Do this after cleanup, outside a hot sampling loop; it can allocate and move entries.

impl<K: Eq + Hash> Motions<K>

pub fn frame<const N: usize>( &mut self, declarations: [(K, Motion); N], window: &mut Window, cx: &App, ) -> [Frame; N]

Samples a batch during render using one executor timestamp and the native reduced-motion preference. Requests one frame if any returned frame is active. Omitted entries do not request frames. Notify the owner after input changes. Do not mix this clock with explicit sample timestamps.

Panics

Panics on duplicate keys, as described by Self::sample.

pub fn frame_one( &mut self, key: K, motion: Motion, window: &mut Window, cx: &App, ) -> Frame

Samples one native entry. Use Self::frame to synchronize several entries.

Trait Implementations

impl<K: Debug> Debug for Motions<K>

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

Formats the value using the given formatter.

impl<K> Default for Motions<K>

fn default() -> Self

Returns the “default value” for a type.