Struct Spring 

pub struct Spring { /* private fields */ }

A physical spring policy for spring.

A spring is the counterpart to Transition for values that can be retargeted while they are still moving. A duration-based transition restarts its easing from the value sampled at that instant, which is continuous in position but not in velocity. A spring carries velocity across the retarget, so a value reversed mid-flight decelerates and turns around instead of snapping to a new curve’s initial speed.

Implementations

impl Spring

pub const fn new(response: Duration) -> Self

Builds a spring that reaches its target in about response without overshooting it.

response is not a duration in the sense Transition::new means one. A spring has no end to schedule: this is the period one full oscillation would take without damping, which is the scale the motion is felt at rather than the moment it stops. The remaining fraction of a percent keeps settling past it, until it is within the tolerance Self::with_epsilon sets.

A zero response adopts the target on the spot, as a zero duration does for a transition. Say that with Self::with_travel where it is what you mean; a zero here is the degenerate case, defined so an infinitely stiff spring resolves rather than dividing by its own period.

pub const fn with_damping(self, ratio: f32) -> Self

Sets the damping ratio, which is 1.0 — no overshoot — by default.

Below 1.0 the spring passes its target and comes back; above 1.0 it approaches slowly. Overshoot suits a value with room to pass its target and nothing to collide with. A height, an opacity, or anything bounded by the geometry around it should stay at the default.

This is $\zeta$, not GPUI’s SpringConfig::damping, which is the coefficient $c = 2 \zeta \omega_0$.

Panics

Panics when ratio is negative or non-finite. Use Self::try_with_damping when the value is not a trusted constant.

pub const fn try_with_damping(self, ratio: f32) -> Result<Self, SpringError>

Checked form of Self::with_damping.

pub const fn with_travel(self, travel: bool) -> Self

Sets whether the spring travels to its target or adopts it on the spot.

A value the pointer is already moving — a panel being dragged by its resize handle — must not lag behind the pointer, so the spring stops travelling for as long as the drag lasts. Retained state stays pinned to the target meanwhile, so travel resumes from the value the drag released rather than from wherever the spring was when it began.

This says at the call that the motion is suspended, and it says it without disturbing the response, damping or tolerance the spring is configured with — which a policy swapped out for the length of the drag would have to restate or discard.

pub const fn with_epsilon(self, epsilon: f32) -> Self

Sets the settling tolerance, expressed in the target’s own units.

The default suits targets that move within a normalized 0..1 range. A spring over pixels settles perceptibly sooner with a coarser tolerance, which also ends the animation frames that the remaining sub-pixel motion would otherwise request.

Panics

Panics when epsilon is zero, negative, or non-finite. Use Self::try_with_epsilon when the value is not a trusted constant.

pub const fn try_with_epsilon(self, epsilon: f32) -> Result<Self, SpringError>

Checked form of Self::with_epsilon.

pub const fn epsilon(self) -> f32

Returns the settling tolerance in the target’s own units.

Trait Implementations

impl Clone for Spring

fn clone(&self) -> Spring

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Spring

impl Debug for Spring

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

Formats the value using the given formatter.